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Sample records for model spark ignition

  1. Towards a general turbulent combustion model for spark ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Naji, H.; Said, R.; Borghi, R.P.

    1989-01-01

    The prediction of combustion within spark ignition engines needs to take into account the interaction of turbulent fluctuations. Previous attempts at this used a model in which the chemical processes were supposed infinitely fast and the combustion was controlled by turbulent mixing only. This paper describes their progress in extending such models in two directions.

  2. Combustion characteristics of spark-ignition and pilot flame ignition systems in a model Wankel stratified charge engine

    Energy Technology Data Exchange (ETDEWEB)

    Muroki, T. [Kanagawa Inst. of Technology, Dept. of Mechanical Engineering, Kanagawa (Japan); Moriyoshi, Y. [Chiba Univ., Dept. of Electronics and Mechanical Engineering, Chiba (Japan)

    2000-11-01

    In a stratified charge engine, a glow plug pilot flame ignition system has been compared with a spark-ignition system for a model stratified charge Wankel combustion chamber. A motored two-stroke diesel engine was operated as a rapid compression and expansion machine with the cylinder head replaced by a model Wankel combustion chamber designed to simulate the temporal changes of air flow and pressure fields inside the chamber of an actual engine. It was found that the pilot flame ignition system had better ignitability and improved combustion characteristics, especially in the lean mixture range, relative to the spark-ignition system. (Author)

  3. Sensitivity and Effect of Ignition Timing on the Performance of a Spark Ignition Engine: An Experimental and Modeling Study

    Directory of Open Access Journals (Sweden)

    A. H. Kakaee

    2011-01-01

    Full Text Available The performance of a spark ignition engine is investigated under different values of ignition advance. A two-zone burnt/unburned model with the fuel burning rate described by a Wiebe function is used for modeling in-cylinder combustion, and then experiments are carried out to validate the calculated data. By varying the ignition timing, the results of some characteristics such as power, torque, thermal efficiency, pressure, and heat release are obtained and compared. The results show that optimal power and torque are achieved at 31°CA before top dead center, and performance is decreased if this ignition timing is changed. It is also shown that the maximum thermal efficiency is accomplished when peak pressure occurs between 5 and 15°CA after top dead center.

  4. A model for random cyclic pressure variations in spark-ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Chandrashekar, T.K. [Sri Siddhartha Inst. of Technology, Karnataka (India); Antony, A.J. [Sahyadri Inst. of Technology, Mangalore, Karnataka (India)

    2009-07-01

    Cycle-by-cycle (CBC) variation of mean effective pressure in spark ignition engines is always greater than in compression ignition engines and needs to be reduced for better drivability, reduced emissions and increased power output. This study examined the parameters affecting CBC fluctuation and how to reduce the fluctuations. The paper presented two newly developed models designed to simulate the engine combustion process and CBC fluctuation. The mathematical model was outlined in detail with particular reference to model development; the statistical model for CBC fluctuation; and experimental setup. The model was found to be physically realistic and correctly predicted the cyclic variation of pressure to provide fundamental insight into the processes. The combustion model also took the effects of heat transfer and friction into consideration. 7 refs., 1 tab., 14 figs., 1 appendix.

  5. Spark Ignition of Monodisperse Fuel Sprays. Ph.D. Thesis

    Science.gov (United States)

    Danis, Allen M.; Cernansky, Nicholas P.; Namer, Izak

    1987-01-01

    A study of spark ignition energy requirements was conducted with a monodisperse spray system allowing independent control of droplet size, equivalent ratio, and fuel type. Minimum ignition energies were measured for n-heptane and methanol sprays characterized at the spark gap in terms of droplet diameter, equivalence ratio (number density) and extent of prevaporization. In addition to sprays, minimum ignition energies were measured for completely prevaporized mixtures of the same fuels over a range of equivalence ratios to provide data at the lower limit of droplet size. Results showed that spray ignition was enhanced with decreasing droplet size and increasing equivalence ratio over the ranges of the parameters studied. By comparing spray and prevaporized ignition results, the existence of an optimum droplet size for ignition was indicated for both fuels. Fuel volatility was seen to be a critical factor in spray ignition. The spray ignition results were analyzed using two different empirical ignition models for quiescent mixtures. Both models accurately predicted the experimental ignition energies for the majority of the spray conditions. Spray ignition was observed to be probabilistic in nature, and ignition was quantified in terms of an ignition frequency for a given spark energy. A model was developed to predict ignition frequencies based on the variation in spark energy and equivalence ratio in the spark gap. The resulting ignition frequency simulations were nearly identical to the experimentally observed values.

  6. Modeling of Transient Heat Flux in Spark Ignition Engine During Combustion and Comparisons with Experiment

    Directory of Open Access Journals (Sweden)

    T. F. Yusaf

    2005-01-01

    Full Text Available A quasi-one dimensional engine cycle simulation program was developed to predict the transient heat flux during combustion in a spark ignition engine. A two-zone heat release model was utilized to model the combustion process inside the combustion chamber. The fuel, air and burned gas properties throughout the engine cycle were calculated using variable specific heats. The transient heat flux inside the combustion chamber due to the change in the in-cylinder gas temperature and pressure during combustion was determined using the Woschni heat transfer model. The program was written in MATLAB together with the Graphical User Interface (GUI. Numerical results were compared with the experimental measurements and good agreement was obtained. Four thermocouples were used and positioned equi-spaced at 5mm intervals along a ray from the spark plug location on the engine head. These thermocouples were able to capture the heat flux release by the burned gas to the wall during the combustion process including the cycle-to-cycle variations. Pressure sensor was installed at the engine head to capture the pressure change throughout the cycle.

  7. The Effect of Spark Timing on the Spark Ignition

    Directory of Open Access Journals (Sweden)

    Rafeq A. Khalefa

    2013-04-01

    Full Text Available  In this work the effect of spark timing on the spark ignition engines is investigated by computer simulation and experimental test for speeds of (1500,2000,2500,3000 and 3500rpm at spark timing of (20o,30o,40o,50o and 60o before TDC for each speed. This is done in order to find a suitable  mathematical expression for spark ignition advancing with respect to the speed of the engine to predict the correct ignition advance  as in real engines .The results showed that the method of using a mathematical expression is more realistic and reasonable  comparing  with the results obtained by other workers. 

  8. Effect of Equivalence Ratio on Composition and performance of Biogas and Gasoline Exhaust from Spark Ignition Engine by Mathematical Modeling

    Directory of Open Access Journals (Sweden)

    Juntarakod Paramust

    2016-01-01

    Full Text Available This paper presents the numerical computationnal of pressure, temperature and exhaust characteristics of spark ignition engine with biogas as fuel. The solution of non-linear combustion equation systems have been computed, that based on a quasi-one-dimensional engine model, high order iteration method with the equilibrium constants method. Computer program was used to calculate the mole fractions of 10 combustion products when biogas and gasoline fuel are burnt along with variable equivalence ratios. In cylinder chamber model is based on the classical two-zone approach, wherein parameters like heat transfer from the cylinder, blow by energy loss and heat release rate are also considered and calculated. Biogas is defined as fuel produced from using anaerobic digestion of biodegradable or waste materials and the constituents are C5H7O2N, CH4, CO2 N2 H2O of biogas and C7H17 of gosoline. Which general fuel model is specified by way of its CaHbOcNd values. The curve-fitted coefficients of energy were then employed to simulate air and fuels data along with frozen composition and practical chemical equilibrium routines from Gill data. The calculated data were used to plot the various pressure and temperature with the crank angle of each step of four stroke engine cycle and combustion products versus equivalence ratio. All results were compared with gasoline as reference fuel in the spark ignition engine according to the same numerical method.

  9. Laser spark distribution and ignition system

    Science.gov (United States)

    Woodruff, Steven; McIntyre, Dustin L.

    2008-09-02

    A laser spark distribution and ignition system that reduces the high power optical requirements for use in a laser ignition and distribution system allowing for the use of optical fibers for delivering the low peak energy pumping pulses to a laser amplifier or laser oscillator. An optical distributor distributes and delivers optical pumping energy from an optical pumping source to multiple combustion chambers incorporating laser oscillators or laser amplifiers for inducing a laser spark within a combustion chamber. The optical distributor preferably includes a single rotating mirror or lens which deflects the optical pumping energy from the axis of rotation and into a plurality of distinct optical fibers each connected to a respective laser media or amplifier coupled to an associated combustion chamber. The laser spark generators preferably produce a high peak power laser spark, from a single low power pulse. The laser spark distribution and ignition system has application in natural gas fueled reciprocating engines, turbine combustors, explosives and laser induced breakdown spectroscopy diagnostic sensors.

  10. Modelling and simulation of four-cycle spark ignition engines; Modelado y simulacion de motores de encendido por chispa de cuatro tiempos

    Energy Technology Data Exchange (ETDEWEB)

    Morea-Roy, Jesus F.; Munoz, Mariano; Moreno, Francisco; Gonzalez, Alfredo [Zaragoza Univ. (Spain). Centro Politecnico Superior. Lab. de Analisis de Motores

    1996-07-01

    A multi zone thermodynamic modeling is presented that has been used to predict the behaviour in a spark ignition engine. Modeling includes blow by, gas exchange processes, heat transfer and a deep analysis of the gas composition as well as thermodynamical and transport properties. The combustion process is characterized by experimental adjustment of empirical laws. (author)

  11. Cycle Engine Modelling Of Spark Ignition Engine Processes during Wide-Open Throttle (WOT) Engine Operation Running By Gasoline Fuel

    Science.gov (United States)

    Rahim, M. F. Abdul; Rahman, M. M.; Bakar, R. A.

    2012-09-01

    One-dimensional engine model is developed to simulate spark ignition engine processes in a 4-stroke, 4 cylinders gasoline engine. Physically, the baseline engine is inline cylinder engine with 3-valves per cylinder. Currently, the engine's mixture is formed by external mixture formation using piston-type carburettor. The model of the engine is based on one-dimensional equation of the gas exchange process, isentropic compression and expansion, progressive engine combustion process, and accounting for the heat transfer and frictional losses as well as the effect of valves overlapping. The model is tested for 2000, 3000 and 4000 rpm of engine speed and validated using experimental engine data. Results showed that the engine is able to simulate engine's combustion process and produce reasonable prediction. However, by comparing with experimental data, major discrepancy is noticeable especially on the 2000 and 4000 rpm prediction. At low and high engine speed, simulated cylinder pressures tend to under predict the measured data. Whereas the cylinder temperatures always tend to over predict the measured data at all engine speed. The most accurate prediction is obtained at medium engine speed of 3000 rpm. Appropriate wall heat transfer setup is vital for more precise calculation of cylinder pressure and temperature. More heat loss to the wall can lower cylinder temperature. On the hand, more heat converted to the useful work mean an increase in cylinder pressure. Thus, instead of wall heat transfer setup, the Wiebe combustion parameters are needed to be carefully evaluated for better results.

  12. Evaluation and Control of Cyclic Variation in Spark Ignited Engines by a Thermodynic Model

    Institute of Scientific and Technical Information of China (English)

    纪常伟; 张红光

    2004-01-01

    An evaluation method of engine cyclic variation is proposed based on fuzzy mathematics concept. The degree of engine cyclic variation is divided into 4 levels: stable, slight variation, moderate variation and serious variation based on the statistic standard deviation of residual gas temperatures within the specified simulation cycles and the function of cyclic variation is also inducted for the cyclic variation control. Because the degree of engine cyclic variation can be estimated qualitatively, the effective control means can be applied to appease the undesired cyclic variation. Simulation result shows that for a very serious cyclic variation through the proper adjustment of the spark angle and the cyclic variation will disappear.

  13. Modelling and multi-objective optimization of a variable valve-timing spark-ignition engine using polynomial neural networks and evolutionary algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Atashkari, K. [Department of Mechanical Engineering, Faculty of Engineering, The University of Guilan, P.O. Box 3756, Rasht (Iran, Islamic Republic of); Nariman-Zadeh, N. [Department of Mechanical Engineering, Faculty of Engineering, The University of Guilan, P.O. Box 3756, Rasht (Iran, Islamic Republic of)]. E-mail: nnzadeh@guilan.ac.ir; Goelcue, M. [Department of Mechanical Education, Technical Education faculty, Pamukkale University, 20017 Kinikli, Denizli (Turkey); Khalkhali, A. [Department of Mechanical Engineering, Faculty of Engineering, The University of Guilan, P.O. Box 3756, Rasht (Iran, Islamic Republic of); Jamali, A. [Department of Mechanical Engineering, Faculty of Engineering, The University of Guilan, P.O. Box 3756, Rasht (Iran, Islamic Republic of)

    2007-03-15

    The main reason for the efficiency decrease at part load conditions for four-stroke spark-ignition (SI) engines is the flow restriction at the cross-sectional area of the intake system. Traditionally, valve-timing has been designed to optimize operation at high engine-speed and wide open throttle conditions. Several investigations have demonstrated that improvements at part load conditions in engine performance can be accomplished if the valve-timing is variable. Controlling valve-timing can be used to improve the torque and power curve as well as to reduce fuel consumption and emissions. In this paper, a group method of data handling (GMDH) type neural network and evolutionary algorithms (EAs) are firstly used for modelling the effects of intake valve-timing (V {sub t}) and engine speed (N) of a spark-ignition engine on both developed engine torque (T) and fuel consumption (Fc) using some experimentally obtained training and test data. Using such obtained polynomial neural network models, a multi-objective EA (non-dominated sorting genetic algorithm, NSGA-II) with a new diversity preserving mechanism are secondly used for Pareto based optimization of the variable valve-timing engine considering two conflicting objectives such as torque (T) and fuel consumption (Fc). The comparison results demonstrate the superiority of the GMDH type models over feedforward neural network models in terms of the statistical measures in the training data, testing data and the number of hidden neurons. Further, it is shown that some interesting and important relationships, as useful optimal design principles, involved in the performance of the variable valve-timing four-stroke spark-ignition engine can be discovered by the Pareto based multi-objective optimization of the polynomial models. Such important optimal principles would not have been obtained without the use of both the GMDH type neural network modelling and the multi-objective Pareto optimization approach.

  14. Combustion characteristics of spark ignition and pilot flame ignition systems in a stratified charge Wankel type rotary engine; Sojo kyuki bankerugata rotary kikan ni okeru spark plug tenka to pilot kaen tenka ni yoru nensho tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Song, Y.; Moriyoshi, Y.; Wada, Y. [Chiba University, Chiba (Japan); Muroki, T. [Kanagawa Institute of Technology, Kanagawa (Japan)

    1998-05-25

    A pilot flame ignition system, which has superior characteristics in the high ignition energy and the large flame contact area to a conventional spark ignition system, is experimentally examined by the indicated pressure analysis and the high speed direct photography. A model combustion chamber, which simulates a Wankel-type direct injection stratified charge rotary engine, was employed to test the ignition performance of both the pilot flame ignition and spark ignition systems. As a result, it was found that the pilot flame system successfully ignites the very lean charge stratified mixture which the spark system fails to ignite and that the combustion characteristic difference using different ignition systems becomes small as the overall equivalence ratio is increased. 6 refs., 15 figs., 2 tabs.

  15. Spark ignition of aviation fuel in isotropic turbulence

    Science.gov (United States)

    Krisman, Alex; Lu, Tianfeng; Borghesi, Giulio; Chen, Jacqueline

    2016-11-01

    Turbulent spark ignition occurs in combustion engines where the spark must establish a viable flame kernel that leads to stable combustion. A competition exists between kernel growth, due to flame propagation, and kernel attenuation, due to flame stretch and turbulence. This competition can be measured by the Karlovitz number, Ka, and kernel viability decreases rapidly for Ka >> 1 . In this study, the evolution of an initially spherical flame kernel in a turbulent field is investigated at two cases: Ka- (Ka = 25) and Ka+ (Ka = 125) using direct numerical simulation (DNS). A detailed chemical mechanism for jet fuel (Jet-A) is used, which is relevant for many practical conditions, and the mechanism includes a pyrolysis sub-model which is important for the ignition of large hydrocarbon fuels. An auxiliary non-reacting DNS generates the initial field of isotropic turbulence with a turbulent Reynolds number of 500 (Ka-) and 1,500 (Ka+). The kernel is then imposed at the center of the domain and the reacting DNS is performed. The Ka- case survives and the Ka+ case is extinguished. An analysis of the turbulence chemistry interactions is performed and the process of extinction is described. Department of Energy - Office of Basic Energy Science under Award No. DE-SC0001198.

  16. Utilization of Alcohol Fuel in Spark Ignition and Diesel Engines.

    Science.gov (United States)

    Berndt, Don; Stengel, Ron

    These five units comprise a course intended to prepare and train students to conduct alcohol fuel utilization seminars in spark ignition and diesel engines. Introductory materials include objectives and a list of instructor requirements. The first four units cover these topics: ethanol as an alternative fuel (technical and economic advantages,…

  17. The concept of isochoric central spark ignition and its fuel gain in inertial fusion

    CERN Document Server

    Kuzmin, A D

    2004-01-01

    One of the best methods in inertial confinement fusion (ICF) is the concept of central spark ignition, consisting of two distinct regions named as hot and cold regions and formed by hydro-dynamical implosion of fuel micro-sphere central spark ignition method in inertial fusion and fuel pellet design condition in fusion power plant has been investigated and fuel gain for isochoric model in this method is calculated. We have shown the effects of different physical parameters of inertial fusion on fuel gain and optimized limit for fuel density and fuel pellet radius has been calculated.

  18. Testing of the J-2X Augmented Spark Igniter (ASI) and Its Electronics

    Science.gov (United States)

    Osborne, Robin

    2015-01-01

    Reliable operation of the spark ignition system electronics in the J-2X Augmented Spark Igniter (ASI) is imperative in assuring ASI ignition and subsequent Main Combustion Chamber (MCC) ignition events are reliable in the J-2X Engine. Similar to the man-rated J-2 and RS-25 engines, the J-2X ignition system electronics are equipped with spark monitor outputs intended to indicate that the spark igniters are properly energized and sparking. To better understand anomalous spark monitor data collected on the J-2X development engines at NASA Stennis Space Center (SSC), a comprehensive subsystem study of the engine's low- and high-tension spark ignition system electronics was conducted at NASA Marshall Space Flight Center (MSFC). Spark monitor output data were compared to more detailed spark diagnostics to determine if the spark monitor was an accurate indication of actual sparking events. In addition, ignition system electronics data were closely scrutinized for any indication of an electrical discharge in some location other than the firing tip of the spark igniter - a problem not uncommon in the development of high voltage ignition systems.

  19. The Use of Spark Ignition Engine in Domestic Cogeneration

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    Feiza Memet

    2009-10-01

    Full Text Available Cogeneration plants are strongly sustained by EU energy policies, one of the best beneficiary of this technology being residential buildings. This paper focus on spark ignition engine as a cogeneration application in order to supply energy for domestic consumers. Are considered two aspects of this solution: the energetic aspect and the environmental one. The energetic aspect deals with the energetic ratios, while the environmental aspect refers to the nitrogen oxide and carbon monoxide emissions.

  20. Numerical simulation of spark ignition engine using OpenFOAM®

    Directory of Open Access Journals (Sweden)

    B.T. Kannan

    2016-09-01

    Full Text Available The present work is the numerical investigation of Spark Ignition (SI engines using an open source Computational Fluid Dynamics (CFD tool. Investigations on the usage of OpenFOAM® CFD tool has been carried out for the simulation of SI engines using engineFoam solver. Four-valve pent roof type engine is chosen for the present simulations. The standard k–ɛ turbulence model is used along with the Reynolds Averaged Navier Stokes (RANS equations for simulating the flow field. Energy equation and transport equation for regress variable is solved along with the momentum equations. Xi model is used for the transport and Gulder's correlation is used for laminar flame speed. Unstrained model is used for calculating the laminar flame speed velocity. Two simulations are carried out one with cold flow and the other with combustion. For combustion analysis, Iso-octane fuel is used. Average cylinder pressure is tracked for different Crank Angles (CA from −180 to 60. The temperature contours are plotted on a vertical plane inside the cylinder to indicate the rise in temperature due to combustion. The results indicate that the open source CFD code can be an ideal choice for engine designers.

  1. Spark Ignition Characteristics of a L02/LCH4 Engine at Altitude Conditions

    Science.gov (United States)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine s augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

  2. Spark Ignition Characteristics of a LO2/LCH4 Engine at Altitude Conditions

    Science.gov (United States)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine's augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter.s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

  3. Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Azer Yalin; Bryan Willson

    2008-06-30

    Past research has shown that laser ignition provides a potential means to reduce emissions and improve engine efficiency of gas-fired engines to meet longer-term DOE ARES (Advanced Reciprocating Engine Systems) targets. Despite the potential advantages of laser ignition, the technology is not seeing practical or commercial use. A major impediment in this regard has been the 'open-path' beam delivery used in much of the past research. This mode of delivery is not considered industrially practical owing to safety factors, as well as susceptibility to vibrations, thermal effects etc. The overall goal of our project has been to develop technologies and approaches for practical laser ignition systems. To this end, we are pursuing fiber optically coupled laser ignition system and multiplexing methods for multiple cylinder engine operation. This report summarizes our progress in this regard. A partial summary of our progress includes: development of a figure of merit to guide fiber selection, identification of hollow-core fibers as a potential means of fiber delivery, demonstration of bench-top sparking through hollow-core fibers, single-cylinder engine operation with fiber delivered laser ignition, demonstration of bench-top multiplexing, dual-cylinder engine operation via multiplexed fiber delivered laser ignition, and sparking with fiber lasers. To the best of our knowledge, each of these accomplishments was a first.

  4. Diesel engines vs. spark ignition gasoline engines -- Which is ``greener``?

    Energy Technology Data Exchange (ETDEWEB)

    Fairbanks, J.W. [Dept. of Energy, Washington, DC (United States)

    1997-12-31

    Criteria emissions, i.e., NO{sub x}, PM, CO, CO{sub 2}, and H{sub 2}, from recently manufactured automobiles, compared on the basis of what actually comes out of the engines, the diesel engine is greener than spark ignition gasoline engines and this advantage for the diesel engine increases with time. SI gasoline engines tend to get out of tune more than diesel engines and 3-way catalytic converters and oxygen sensors degrade with use. Highway measurements of NO{sub 2}, H{sub 2}, and CO revealed that for each model year, 10% of the vehicles produce 50% of the emissions and older model years emit more than recent model year vehicles. Since 1974, cars with SI gasoline engines have uncontrolled emission until the 3-way catalytic converter reaches operating temperature, which occurs after roughly 7 miles of driving. Honda reports a system to be introduced in 1998 that will alleviate this cold start problem by storing the emissions then sending them through the catalytic converter after it reaches operating temperature. Acceleration enrichment, wherein considerable excess fuel is introduced to keep temperatures down of SI gasoline engine in-cylinder components and catalytic converters so these parts meet warranty, results in 2,500 times more CO and 40 times more H{sub 2} being emitted. One cannot kill oneself, accidentally or otherwise, with CO from a diesel engine vehicle in a confined space. There are 2,850 deaths per year attributable to CO from SI gasoline engine cars. Diesel fuel has advantages compared with gasoline. Refinery emissions are lower as catalytic cracking isn`t necessary. The low volatility of diesel fuel results in a much lower probability of fires. Emissions could be improved by further reducing sulfur and aromatics and/or fuel additives. Reformulated fuel has become the term covering reducing the fuels contribution to emissions. Further PM reduction should be anticipated with reformulated diesel and gasoline fuels.

  5. Intake Manifold Boosting of Turbocharged Spark-Ignited Engines

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    Lino Guzzella

    2013-03-01

    Full Text Available Downsizing and turbocharging is a widely used approach to reduce the fuel consumption of spark ignited engines while retaining the maximum power output. However, a substantial loss in drivability must be expected due to the occurrence of the so-called turbo lag. The turbo lag results from the additional inertia that the turbocharger adds to the system. Supplying air by an additional valve, the boost valve, to the intake manifold can be used to overcome the turbo lag. This turbo lag compensationmethod is referred to as intakemanifold boosting. The aims of this study are to show the effectiveness of intake manifold boosting on a turbocharged spark-ignited engine and to show that intake manifold boosting can be used as an enabler of strong downsizing. Guidelines for the dimensioning of the boost valve are given and a control strategy is presented. The trade-off between additional fuel consumption and the consumption of pressurized air during the turbo lag compensation is discussed. For a load step at 2000 rpm the rise time can be reduced from 2.8 s to 124ms, requiring 11.8 g of pressurized air. The transient performance is verified experimentally by means of load steps at various engine speeds to various engine loads.

  6. Experimental Study on Methane Explosion Ignited by Sparks of Cable Bolt Breakage

    Institute of Scientific and Technical Information of China (English)

    MA Wen-ding; XU Jia-lin; ZHANG Shao-hua

    2004-01-01

    An experimental device was designed for studying methane explosion ignited by sparks of cable bolt breakage. With the methane concentration being in explosion range, a series of experiments were conducted to study the law of spark generation during cable bolt breakage and the probability of methane explosion caused by the spark. The results show that the probability of generating sparks during cable bolt breakage is 50%. The spark generated by the breakage of steel cable bolt strand can't ignite a methane explosion. A detection was carried out using infrared-ray imaging apparatus (IRIA) to measure temperature of the spark generated by cable bolt breakage. It is indicated that the maximum temperature of the spark generated by cable bolt breakage is far less than the required ignition temperature for a methane explosion.

  7. Influence of hydrox on spark ignition engine performance

    Energy Technology Data Exchange (ETDEWEB)

    Naude, A.F. [University of Pretoria, Pretoria (South Africa). Dept. of Mechanical and Aeronautical Engineering

    2003-07-01

    A series of experiments were conducted on a Mazda 1600 cc fuel injected engine connected to a Superflow SF901 dynamometer system to examine the influence of small quantities of Hydrox (hydrogen and oxygen), as generated through electrolysis of water, on the performance of a spark ignition engine. The engine was also equipped with a Unichip engine management system in order to enable changes in the spark timing and the amount of fuel injected. Electrolysis was used to generate Hydrox. The process could either be powered from a separate power source or from the engine's alternator. Hydrox was introduced into the engine's intake manifold, and measurements were taken of the engine's performance, emissions and fuel consumption. The authors simulated a typical load condition as experienced for a light passenger car operating at 100 kilometres per hour on the open road. A significant reduction in hydrocarbons at lean air-fuel ratio operation of the engine was observed with the introduction of Hydrox, and there was also a slight improvement in fuel consumption when the electrolysis process was driven by the engine. 2 refs., 1 tab., 5 figs.

  8. Studies on effect of spark advance angle and spark gap on cycle-by-cycle fluctuations in four stroke spark ignition engine

    Energy Technology Data Exchange (ETDEWEB)

    Bhaskar, H.B.; Chandrasheaker, T.K. [Sri Siddhartha Inst. of Technology, Maralur, Tumkur (India). Dept. of Mechanical Engineering; Antony, A.J. [Sahyedri Inst. of Technology, Mangalore (India)

    2009-07-01

    In response to environmental concerns and the depletion of fossil fuels, the automotive industry is striving to increase fuel efficiency and reduce emissions such as soot and nitrous oxides (NOx). This paper focused on the nature of cyclic variability and its manifestation in the characteristics of spark-ignition (SI) engine combustion. Cycle-by-cycle fluctuation is a major phenomenon that limits the range of operating conditions. The parameters affecting cycle-by-cycle fluctuation include mixture distribution, mixture homogeneity, spark intensity, spark timing, spark plug location, spark plug gap, number of spark plugs, swirl, combustion chamber geometry, compression ratio, equivalence ratio, load and speed. The degree to which these parameters influence cycle-by-cycle fluctuations was investigated. The cycle-by-cycle fluctuations in the engine reduces the power output, but increases the engine roughness and emissions. Experiments were carried out on a four stroke single cylinder computerized spark ignition engine. The results revealed the best operating spark gap and advanced spark angle to minimize the cycle-by-cycle fluctuations. The overall engine performance was improved with better drivability. 6 refs., 3 tabs., 10 figs.

  9. Application of Alcohols to Dual - Fuel Feeding the Spark-Ignition and Self-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Stelmasiak Zdzisław

    2014-10-01

    Full Text Available This paper concerns analysis of possible use of alcohols for the feeding of self - ignition and spark-ignition engines operating in a dual- fuel mode, i.e. simultaneously combusting alcohol and diesel oil or alcohol and petrol. Issues associated with the requirements for application of bio-fuels were presented with taking into account National Index Targets, bio-ethanol production methods and dynamics of its production worldwide and in Poland. Te considerations are illustrated by results of the tests on spark- ignition and self- ignition engines fed with two fuels: petrol and methanol or diesel oil and methanol, respectively. Te tests were carried out on a 1100 MPI Fiat four- cylinder engine with multi-point injection and a prototype collector fitted with additional injectors in each cylinder. Te other tested engine was a SW 680 six- cylinder direct- injection diesel engine. Influence of a methanol addition on basic operational parameters of the engines and exhaust gas toxicity were analyzed. Te tests showed a favourable influence of methanol on combustion process of traditional fuels and on some operational parameters of engines. An addition of methanol resulted in a distinct rise of total efficiency of both types of engines at maintained output parameters (maximum power and torque. In the same time a radical drop in content of hydrocarbons and nitrogen oxides in exhaust gas was observed at high shares of methanol in feeding dose of ZI (petrol engine, and 2-3 fold lower smokiness in case of ZS (diesel engine. Among unfavourable phenomena, a rather insignificant rise of CO and NOx content for ZI engine, and THC and NOx - for ZS engine, should be numbered. It requires to carry out further research on optimum control parameters of the engines. Conclusions drawn from this work may be used for implementation of bio-fuels to feeding the combustion engines.

  10. Aspects of the bioethanol use at the turbocharged spark ignition engine

    Directory of Open Access Journals (Sweden)

    Obeid Zuhair

    2015-01-01

    Full Text Available In the actual content of pollution regulations for the automotives, the use of alternative fuels becomes a priority of the thermal engine scientific research domain. From this point of view bioethanol can represents a viable alternative fuel for spark ignition engines offering the perspective of pollutant emissions reduction and combustion improvement. The paper presents results of the experimental investigations of a turbo-supercharged spark ignition engine (developed from a natural admission spark ignition engine fuelled with gasoline fuelled with bioethanol-gasoline blends. The engine is equipped with a turbocharger for low pressure supercharging, up till 1.4 bar. An correlation between air supercharging pressure-compression ratio-dosage-spark ignition timing-brake power is establish to avoid knocking phenomena at the engine operate regime of full load and 3000 min-1. The influences of the bioethanol on pollutant emissions level are presented.

  11. Investigation of Spark Ignition and Autoignition in Methane and Air Using Computational Fluid Dynamics and Chemical Reaction Kinetics. A numerical Study of Ignition Processes in Internal Combustion Engines

    Energy Technology Data Exchange (ETDEWEB)

    Nordrik, R.

    1993-12-01

    The processes in the combustion chamber of internal combustion engines have received increased attention in recent years because their efficiencies are important both economically and environmentally. This doctoral thesis studies the ignition phenomena by means of numerical simulation methods. The fundamental physical relations include flow field conservation equations, thermodynamics, chemical reaction kinetics, transport properties and spark modelling. Special attention is given to the inclusion of chemical kinetics in the flow field equations. Using his No Transport of Radicals Concept method, the author reduces the computational efforts by neglecting the transport of selected intermediate species. The method is validated by comparison with flame propagation data. A computational method is described and used to simulate spark ignition in laminar premixed methane-air mixtures and the autoignition process of a methane bubble surrounded by hot air. The spark ignition simulation agrees well with experimental results from the literature. The autoignition simulation identifies the importance of diffusive and chemical processes acting together. The ignition delay times exceed the experimental values found in the literature for premixed ignition delay, presumably because of the mixing process and lack of information on low temperature reactions in the skeletal kinetic mechanism. Transient turbulent methane jet autoignition is simulated by means of the KIVA-II code. Turbulent combustion is modelled by the Eddy Dissipation Concept. 90 refs., 81 figs., 3 tabs.

  12. Experimental Investigation of Augmented Spark Ignition of a LO2/LCH4 Reaction Control Engine at Altitude Conditions

    Science.gov (United States)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of nontoxic propellants in future exploration vehicles would enable safer, more cost-effective mission scenarios. One promising green alternative to existing hypergols is liquid methane (LCH4) with liquid oxygen (LO2). A 100 lbf LO2/LCH4 engine was developed under the NASA Propulsion and Cryogenic Advanced Development project and tested at the NASA Glenn Research Center Altitude Combustion Stand in a low pressure environment. High ignition energy is a perceived drawback of this propellant combination; so this ignition margin test program examined ignition performance versus delivered spark energy. Sensitivity of ignition to spark timing and repetition rate was also explored. Three different exciter units were used with the engine s augmented (torch) igniter. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks. This suggests that rising pressure and flow rate increase spark impedance and may at some point compromise an exciter s ability to complete each spark. The reduced spark energies of such quenched deliveries resulted in more erratic ignitions, decreasing ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1 to 6 mJ, though multiple, similarly timed sparks of 55 to 75 mJ were required for reliable ignition. Delayed spark application and reduced spark repetition rate both correlated with late and occasional failed ignitions. An optimum time interval for spark application and ignition therefore coincides with propellant introduction to the igniter.

  13. Utilization of waste glycerin to fuelling of spark ignition engines

    Science.gov (United States)

    Stelmasiak, Z.; Pietras, D.

    2016-09-01

    The paper discusses a possibilities of usage a simple alcohols to fuelling of spark ignition engines. Methanol and blends of methanol with glycerin, being a waste product from production of bio-components to fuels based on rapeseed oil, have been used in course of the investigations. The main objective of the research was to determine possibilities of utilization of glycerin to blending of engine fuels. The investigations have been performed using the Fiat 1100 MPI engine. Parameters obtained with the engine powered by pure methanol and by methanol- glycerin mixtures with 10÷30%vol content of glycerin were compared to parameters of the engine fuelled conventionally with the E95 gasoline. The investigations have shown increase of overall efficiency of the engine run on pure methanol with 2.5÷5.0%, and run on the mixture having 10% addition of glycerin with 2.0÷7.8%. Simultaneously, fuelling of the engine with the investigated alcohols results in reduced concentration of toxic components in exhaust gases like: CO, THC and NOx, as well as the greenhouse gas CO2.

  14. Homogeneous charge compression ignition (HCCI) - A comparison with spark ignition (SI) operation

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Magnus

    1997-08-01

    Homogeneous Charge Compression Ignition (HCCI) is the third alternative for combustion in engines. Here a homogeneous premixed charge is used as in a spark ignited engine but the charge is compressed to auto-ignition as in a diesel. The characteristics of HCCI was compared to spark ignition (SI) using a 1.6 liter single cylinder engine. Three different fuels were used; isooctane, ethanol and natural gas. HCCI could be used with all three fuels in a single cylinder engine with a fixed compression ratio. Some remarkable results were noted in the experiments. The indicated efficiency of HCCI was much better than for SI operation. The gross indicated efficiency showed values at 50% for the richer cases. This means that the fuel consumption at part load would be reduced to the half compared to SI operation. Very little NO{sub x} was generated with HCCI, only a few ppm. With isooctane, it ranged from 4 to below 1 ppm and with ethanol even lower values. However, HCCI generated more HC and CO. Operation was noisier with HCCI than with SI. Stable and efficient operation with HCCI could be obtained with {lambda} = 3.5 to 9 using isooctane, 3.5 to 6.5 using ethanol, and 2.5 to 3.5 using natural gas. Cycle to cycle variation of combustion was very low. Isooctane could be operated unthrottled without preheating. The selection of the high compression ratio, 21:1, was dependent on the high octane number for natural gas. The attainable IMEP was 5 bar. The limit to make higher IMEP was the rate of combustion. At IMEP 5 bar the main combustion, 10-90% burn duration, took place in less than 2 crank angle degrees (CAD). This is extremely fast and gives very high rate of pressure rise, which leads to noisy operation and high loads on the engine. The lean limit was given by unstable combustion with cycle to cycle variation of combustion, and with high emissions of unburned hydrocarbons and carbon monoxide Examination paper. 15 refs, 38 figs, 1 tab

  15. Internal combustion engines a detailed introduction to the thermodynamics of spark and compression ignition engines, their design and development

    CERN Document Server

    Benson, Rowland S

    1979-01-01

    Internal Combustion of Engines: A Detailed Introduction to the Thermodynamics of Spark and Compression Ignition Engines, Their Design and Development focuses on the design, development, and operations of spark and compression ignition engines. The book first describes internal combustion engines, including rotary, compression, and indirect or spark ignition engines. The publication then discusses basic thermodynamics and gas dynamics. Topics include first and second laws of thermodynamics; internal energy and enthalpy diagrams; gas mixtures and homocentric flow; and state equation. The text ta

  16. Review: Fuel Volatility Standards and Spark-Ignition Vehicle Driveability

    Energy Technology Data Exchange (ETDEWEB)

    Yanowitz, Janet; McCormick, Robert L.

    2016-03-14

    We've put spark-ignition engine fuel standards in place in order to ensure acceptable hot and cold weather driveability (HWD and CWD). Vehicle manufacturers and fuel suppliers have developed systems that meet our driveability requirements so effectively that drivers overwhelmingly find that their vehicles reliably start up and operate smoothly and consistently throughout the year. For HWD, fuels that are too volatile perform more poorly than those that are less volatile. Vapor lock is the apparent cause of poor HWD, but there is conflicting evidence in the literature as to where in the fuel system it occurs. Most studies have found a correlation between degraded driveability and higher dry vapor pressure equivalent or lower TV/L = 20, and less consistently with a minimum T50. For CWD, fuels with inadequate volatility can cause difficulty in starting and rough operation during engine warmup. The Driveability Index (DI)-a function of T10, T50, and T90-is well correlated with CWD in hydrocarbon fuels. For ethanol-containing fuels, a correction factor to the DI equation improves the correlation with CWD, although the best value for that factor has still not been determined. Ethanol increases the heat of vaporization. But, this is likely insignificant for E15 and lower concentration fuels. The impact of ethanol on driveability is likely due to its direct effect on vapor pressure at cold temperatures. For E51-E83 or flex-fuel blends, ASTM sets a minimum vapor pressure; however, published data suggest that a correction for the amount of ethanol in the fuel is needed to accurately predict CWD, possibly because ethanol has a higher lower-flammability limit.

  17. Development And Testing Of Biogas-Petrol Blend As An Alternative Fuel For Spark Ignition Engine

    Directory of Open Access Journals (Sweden)

    Awogbemi

    2015-08-01

    Full Text Available Abstract This research is on the development and testing of a biogas-petrol blend to run a spark ignition engine. A2080 ratio biogaspetrol blend was developed as an alternative fuel for spark ignition engine test bed. Petrol and biogas-petrol blend were comparatively tested on the test bed to determine the effectiveness of the fuels. The results of the tests showed that biogas petrol blend generated higher torque brake power indicated power brake thermal efficiency and brake mean effective pressure but lower fuel consumption and exhaust temperature than petrol. The research concluded that a spark ignition engine powered by biogas-petrol blend was found to be economical consumed less fuel and contributes to sanitation and production of fertilizer.

  18. THE EFFECT OF COMPRESSION RATIO VARIATIONS ON THE ENGINE PERFORMANCE PARAMETRES IN SPARK IGNITION ENGINES

    Directory of Open Access Journals (Sweden)

    Yakup SEKMEN

    2005-01-01

    Full Text Available Performance of the spark ignition engines may be increased by changing the geometrical compression ratio according to the amount of charging in cylinders. The designed geometrical compression ratio can be realized as an effective compression ratio under the full load and full open throttle conditions since the effective compression ratio changes with the amount of charging into the cylinder in spark ignition engines. So, this condition of the spark ignition engines forces designers to change their geometrical compression ratio according to the amount of charging into the cylinder for improvement of performance and fuel economy. In order to improve the combustion efficiency, fuel economy, power output, exhaust emissions at partial loads, compression ratio must be increased; but, under high load and low speed conditions to prevent probable knock and hard running the compression ratio must be decreased gradually. In this paper, relation of the performance parameters to compression ratio such as power, torque, specific fuel consumption, cylindir pressure, exhaust gas temperature, combustion chamber surface area/volume ratio, thermal efficiency, spark timing etc. in spark ignition engines have been investigated and using of engines with variable compression ratio is suggested to fuel economy and more clear environment.

  19. Measurements of some parameters of thermal sparks with respect to their ability to ignite aviation fuel/air mixtures

    Science.gov (United States)

    Haigh, S. J.; Hardwick, C. J.; Baldwin, R. E.

    1991-01-01

    A method used to generate thermal sparks for experimental purposes and methods by which parameters of the sparks, such as speed, size, and temperature, were measured are described. Values are given of the range of such parameters within these spark showers. Titanium sparks were used almost exclusively, since it is particles of this metal which are found to be ejected during simulation tests to carbon fiber composite (CFC) joints. Tests were then carried out in which titanium sparks and spark showers were injected into JP4/(AVTAG F40) mixtures with air. Single large sparks and dense showers of small sparks were found to be capable of causing ignition. Tests were then repeated using ethylene/air mixtures, which were found to be more easily ignited by thermal sparks than the JP4/ air mixtures.

  20. Experimental evaluation of a spark-ignited engine using biogas as fuel

    Directory of Open Access Journals (Sweden)

    Juan Miguel Mantilla González

    2010-07-01

    Full Text Available Different CH4 and CO2 mixtures were used as fuel in this work; they were fed into a spark-ignited engine equipped with devices allowing spark advance, gas delivery and gas consumption to be measured. Engine bench-tests re-vealed changes in the main operation parameters and emissions. The results showed that increasing CO2 percen-tage in the mixture increased the spark angle, reduced maximum power and torque and reduced exhaust emissions (by 90% in some cases when DAMA resolution 1015/2005 was applied. The main components to be considered when an engine of this type operates with gas fuel were also recognised.

  1. Cavity Ignition in Supersonic Flow by Spark Discharge and Pulse Detonation

    Science.gov (United States)

    2014-08-18

    constant volume, through a detonation , or some combination. While a deflagration (flame) through constant volume combustion can provide rapid heat release...significantly disrupted, and the detonation was able to ignite and burn most of the fuel within the cavity. This led to decreased heat release in regime IV...locate/proci of the Combustion InstituteCavity ignition in supersonic flow by spark discharge and pulse detonation Timothy M. Ombrello a,⇑, Campbell D

  2. Research of combustion in older generation spark-ignition engines in the condition of use leaded and unleaded petrol

    Directory of Open Access Journals (Sweden)

    Bulatović Željko M.

    2014-01-01

    Full Text Available This paper analyzes the potential problems in the exploitation of the older generation of spark-ignition engines with higher octane number of petrol (unleaded petrol BMB 95 than required (leaded petrol MB 86. Within the experimental tests on two different engines (STEYR-PUCH model 712 and GAZ 41 by applying piezoelectric pressure sensors integrated with the engine spark plugs, acceleration sensors (accelerometers and special electronic block connected with distributor, show that the cumulative first and second theoretical phase of combustion when petrol of higher octane number (BMB 95 is used lasts slightly longer than when the low-octane petrol MB 86 is used. For new petrol (BMB 95 higher optimal angles of pre-ignition have been determined by which better performances of the engine are achieved without a danger of the combustion with detonation (also called knocking.

  3. Prediction of small spark ignited engine performance using producer gas as fuel

    Directory of Open Access Journals (Sweden)

    N. Homdoung

    2015-03-01

    Full Text Available Producer gas from biomass gasification is expected to contribute to greater energy mix in the future. Therefore, effect of producer gas on engine performance is of great interest. Evaluation of engine performances can be hard and costly. Ideally, they may be predicted mathematically. This work was to apply mathematical models in evaluating performance of a small producer gas engine. The engine was a spark ignition, single cylinder unit with a CR of 14:1. Simulation was carried out on full load and varying engine speeds. From simulated results, it was found that the simple mathematical model can predict the performance of the gas engine and gave good agreement with experimental results. The differences were within ±7%.

  4. Numerical Simulation of a Spark Ignited Two-Stroke Free-Piston Engine Generator

    Institute of Scientific and Technical Information of China (English)

    MAO Jin-long; ZUO Zheng-xing; LIU Dong

    2009-01-01

    A numerical program is built to simulate the performance of a spark ignited two-stroke free-piston engine coupled with a linear generator. The computational model combines a series of dynamic and thermodynamic equations that are solved simultaneously to predict the performances of the engines. The dynamic analysis performed consists of an evaluation of the frictional force and load force introduced by the generator. The thermodynamic analysis used a single zone model to describe the engine's working cycle which includes intake, scavenging, compression, combustion and expansion, and to evaluate the effect of heat transfer based on the first law of thermodynamics and the ideal gas state equation. Because there is no crankshaft, a time based Wiebe equation was used to express the fraction of fuel burned in the combustion. The calculated results were validated by using the experimental data from another research group. The results indicate that the free-piston generator has some advantages over conventional engines.

  5. BIOSTABILITY OF USED LUBRICATING OILS FOR HIGH-SPEED ENGINES WITH SPARK IGNITION

    OpenAIRE

    YUSIFOVA AIDA RAFIQ QIZI; RAFIYEV AZAD NATIG OGLU

    2015-01-01

    The article presents the investigation results of the biological stability of the waste and regenerated lubricating oil Mysella-40, designed for high-speed engines with spark ignition. Biocides were prepared to protect the oil from microbial destruction. It was found that the use of biocides in the recommended concentration has no negative effect on the basic performance of the lubricating oil.

  6. Knock Detection in Spark Ignition Engines Base on Complementary Ensemble Empirical Mode Decomposition-Hilbert Transform

    Directory of Open Access Journals (Sweden)

    Fengrong Bi

    2016-01-01

    Full Text Available In spark ignition engines, knock onset limits the maximum spark advance. An inaccurate identification of this limit penalises the fuel conversion efficiency. Thus knock feature extraction is the key of closed-loop control of ignition in spark ignition engine. This paper reports an investigation of knock detection in spark ignition (SI engines using CEEMD-Hilbert transform based on the engine cylinder pressure signals and engine cylinder block vibration signals. Complementary Ensemble Empirical Mode Decomposition (CEEMD was used to decompose the signal and detect knock characteristic. Hilbert transform was used to analyze the frequency information of knock characteristic. The result shows that, for both of cylinder pressure signals and vibration signals, the CEEMD algorithm could extract the knock characteristic, and the Hilbert transform result shows that the energy of knock impact areas has the phenomenon of frequency concentration in both cylinder pressure signal and cylinder block vibration signal. At last, the knock window is then determined, based on which a new knock intensity evaluation factor K is propose, and it can accurately distinguish between heavy knock, light knock, and normal combustion three states.

  7. Enhancement of flame development by microwave-assisted spark ignition in constant volume combustion chamber

    KAUST Repository

    Wolk, Benjamin

    2013-07-01

    The enhancement of laminar flame development using microwave-assisted spark ignition has been investigated for methane-air mixtures at a range of initial pressures and equivalence ratios in a 1.45. l constant volume combustion chamber. Microwave enhancement was evaluated on the basis of several parameters including flame development time (FDT) (time for 0-10% of total net heat release), flame rise time (FRT) (time for 10-90% of total net heat release), total net heat release, flame kernel growth rate, flame kernel size, and ignitability limit extension. Compared to a capacitive discharge spark, microwave-assisted spark ignition extended the lean and rich ignition limits at all pressures investigated (1.08-7.22. bar). The addition of microwaves to a capacitive discharge spark reduced FDT and increased the flame kernel size for all equivalence ratios tested and resulted in increases in the spatial flame speed for sufficiently lean flames. Flame enhancement is believed to be caused by (1) a non-thermal chemical kinetic enhancement from energy deposition to free electrons in the flame front and (2) induced flame wrinkling from excitation of flame (plasma) instability. The enhancement of flame development by microwaves diminishes as the initial pressure of the mixture increases, with negligible flame enhancement observed above 3. bar. © 2013 The Combustion Institute.

  8. Modelling of a Spark Ignition Engine for Power-Heat Production Optimization Modèle de moteur à allumage commandé en vue de l’optimisation de la production chaleur-force

    OpenAIRE

    Descieux D.; Feidt M.

    2011-01-01

    Spark ignition gas engine is more and more used in order to produce electricity and heat simultaneously. The engine crankshaft drives a synchronous electric generator. The thermal power output is recovered from the engine coolant system and exhaust gas, and is used to produce generally hot water for heating system. In order to have a better adequacy between supply (production of the engine) and user demand, good knowledge of the engine and implemented phenomena are necessary. A generic method...

  9. Are Published Minimum Vapor Phase Spark Ignition Energy Data Valid?

    Energy Technology Data Exchange (ETDEWEB)

    Staggs, K J; Alvares, N J; Greenwood, D W

    2001-11-21

    The use of sprayed flammable fluids as solvents in dissolution and cleaning processes demand detailed understanding of ignition and fire hazards associated with these applications. When it is not feasible to inert the atmosphere in which the spraying process takes place, then elimination of all possible ignition sources must be done. If operators are involved in the process, the potential for human static build-up and ultimate discharge is finite, and it is nearly impossible to eliminate. The specific application discussed in this paper involved the use of heated Dimethyl Sulfoxide (DMSO) to dissolve high explosives (HE). Search for properties of DMSO yielded data on flammability limits and flash point, but there was no published information pertaining to the minimum energy for electrical arc ignition. Due to the sensitivity of this procedure, The Hazards Control Department of Lawrence Livermore National Laboratory (LLNL) was tasked to determine the minimum ignition energy of DMSO aerosol and vapor an experimental investigation was thus initiated. Because there were no electrical sources in spray chamber, Human Electro-Static Discharge (HESD) was the only potential ignition source. Consequently, the electrostatic generators required for this investigation were designed to produce electrostatic arcs with the defined voltage and current pulse characteristics consistent with simulated human capacitance. Diagnostic procedures required to insure these characteristics involve specific data gathering techniques where the voltage and current sensors are in close proximity to the electrodes, thus defining the arc energy directly between the electrodes. The intriguing finding derived from this procedure is how small these measured values are relative to the arc energy as defined by the capacitance and the voltage measure at the capacitor terminals. The suggested reason for this difference is that the standard procedure for determining arc energy from the relation; E = 1/2CV

  10. Ignition of Isomers of Pentane: An Experimental and Kinetic Modeling Study

    Science.gov (United States)

    2000-08-04

    diesel engines [26,27], and ignition under homogeneous charge compres- sion ignition ( HCCI ) conditions [26,28]. Kinetic modeling shows that the isomers of...Introduction Hydrocarbon ignition is important in many prac- tical combustion systems, including internal com- bustion engines , detonations, pulse combustors...tem- peratures are similar to those in automotive engines during diesel ignition and end-gas autoignition in spark-ignition engines . The RCM provides

  11. Simulation and validation of spark ignition engine performance on E85

    Energy Technology Data Exchange (ETDEWEB)

    Varde, Keshav V. [Michigan Univ., Dearborn (United States)

    2013-06-01

    Alcohol based fuels have been promoted as alternatives to gasoline to power light-duty vehicles. One of the fuels that has received significant attention and has been used in limited number of spark ignition (SI) engines is E85, a blend of 85% ethanol and 15% gasoline. The fuel has several attractive properties that make it suitable for use in SI engines. But E85 has low energy content and high heat of vaporization which can potentially impact engine performance at low temperatures. One of the ways to evaluate engine performance at low coolant temperatures is through experimentation; however, simulation of engine combustion processes through well-developed models could help alleviate costly experimental tests. In this work an experimental study was conducted to evaluate performance of an automotive type, 4-cylinder spark ignition engine operating on E85. The port fuel injected engine was operated at stoichiometric condition at light loads and low coolant temperatures, conditions similar to those experienced during engine warm-up. The E85 performance was compared with the performance of the engine when operated on unleaded gasoline (EO). The exhaust hydrocarbon emissions in E85 fueled engine exhaust contained acetaldehyde and methane. For identical operating conditions the acetaldehyde emissions increased as the coolant temperature was reduced or EGR rates were increased. The methane levels in the engine exhaust were generally higher with E85 than those found in unleaded gasoline; they also increased with reduction in coolant temperature. The thermal efficiency of the engine on E85 was comparable to that measured with unleaded gasoline. In addition, a simulation model was used to predict SI engine performance when operating on E85. The model, based on GT-Power, was calibrated using cylinder pressure Vs crank angle data collected when the engine was operating on unleaded gasoline. The calibrated model, with appropriate modifications, was used to predict fuel

  12. The Application of High Energy Ignition and Boosting/Mixing Technology to Increase Fuel Economy in Spark Ignition Gasoline Engines by Increasing EGR Dilution Capability

    Energy Technology Data Exchange (ETDEWEB)

    Keating, Edward [General Motors LLC, Pontiac, MI (United States); Gough, Charles [General Motors LLC, Pontiac, MI (United States)

    2015-07-07

    This report summarizes activities conducted in support of the project “The Application of High Energy Ignition and Boosting/Mixing Technology to Increase Fuel Economy in Spark Ignition Gasoline Engines by Increasing EGR Dilution Capability” under COOPERATIVE AGREEMENT NUMBER DE-EE0005654, as outlined in the STATEMENT OF PROJECT OBJECTIVES (SOPO) dated May 2012.

  13. About the constructive and functional particularities of spark ignition engines with gasoline direct injection: experimental results

    Science.gov (United States)

    Niculae, M.; Ivan, F.; Neacsu, D.

    2017-08-01

    The paper aims to analyze and compare the environmental performances between a gasoline direct engine and a multi-point injection engine. There are analyzed the stages of emission formation during the New European Driving Cycle. The paper points out the dynamic, economic and environmental performances of spark ignition engines equipped with a GDI systems. Reason why, we believe the widespread implementation of this technology is today an immediate need.

  14. Method for operating a spark-ignition, direct-injection internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Narayanaswamy, Kushal; Koch, Calvin K.; Najt, Paul M.; Szekely, Jr., Gerald A.; Toner, Joel G.

    2015-06-02

    A spark-ignition, direct-injection internal combustion engine is coupled to an exhaust aftertreatment system including a three-way catalytic converter upstream of an NH3-SCR catalyst. A method for operating the engine includes operating the engine in a fuel cutoff mode and coincidentally executing a second fuel injection control scheme upon detecting an engine load that permits operation in the fuel cutoff mode.

  15. AN INVESTIGATION OF THE EFFECTS OF INTAKE VALVE LIFT ON THE PERFORMANCE IN SPARK IGNITION ENGINES

    Directory of Open Access Journals (Sweden)

    Can ÇINAR

    2004-02-01

    Full Text Available In this study, the effects of intake valve lift variation on engine performance have been investigated experimentally. An alternative prototype has been designed and constructed for variable valve systems. A fourstroke, single cylinder, spark ignition engine has been used for experiments. The effects of four different intake valve lift value (6.5 mm, 5 mm, 4 mm and 3 mm on volumetric efficiency, engine torque, specific fuel consumption and exhaust emissions have been investigated.

  16. Experimental determination of the filling coefficient for an aspirated spark-ignition engine

    Science.gov (United States)

    Raţiu, S.; Alexa, V.; Kiss, I.; Cioată, V.

    2017-01-01

    This study aims at determining, by experiment, the filling coefficient of a spark-ignition, normal aspirated engine, with carburettor. For this purpose, a pilot plant was designed for measuring the pressure at various points on the route, simulating a stationary air flow regime by means of a vacuum pump. Measurements were made for various lifting heights of the intake valve and various opening positions of the throttle body, thus highlighting how their influence on the pressure loss and on the filling coefficient.

  17. Different Boosting Systems and their Control Strategies for a Spark Ignition Internal Combustion Engine

    OpenAIRE

    Bolehovský Ondřej; Macek Jan

    2016-01-01

    This research uses 1-D simulation in GT-Power for evaluation of boosting systems for a spark ignition engine. Exhaust gas driven (waste-gated turbocharger) and mechanical driven (Roots blower) boosting systems are assessed in both steady state and transient modes in terms of performance, efficiency, fuel consumption, drivability, energy distribution and other aspects that influence gas exchange phase. Moreover, different boost control strategies, particularly at partial load, are also evaluat...

  18. Effect of biofuel E85 combustion on fuel consumption in spark-ignition engines

    Directory of Open Access Journals (Sweden)

    Adam Polcar

    2012-01-01

    Full Text Available Biofuels represent an alternative source of energy that should gradually decrease our dependence on crude oil. A rapid development of their use in combustion engines is above all the consequence of their very positive balance of emissions. The possibility of use of biofuels in conventional combustion engines is given by their physico-chemical properties. Bioethanol is one of biofuels that can be used in spark-ignition engines. However, because of its lower heating value, it is necessary to change the mixing ratio fuel/air. The aim of this paper is to evaluate the effect of combustion of a mixture of bioethanol with gasoline (in the ratio 85:15 on fuel consumption in the spark-ignition engine. Experimental measurements were performed using a six-cylinder spark-ignition Peugeot engine with the overall volume of 2.946 cm3, which was equipped with a multi-hole system of indirect injection. Obtained results indicated that the combustion of E85 biofuel markedly increased the reduction of specific fuel consumption (corrected to atmospheric conditions. As compared with gasoline Natural 95, the actual volume consumption of E85 biofuel increased under the maximum engine load in average by 30.4 %. In spite of a relatively high consumption of E85 biofuel the total costs associated with running of a modified engine were lower than those of the engine combusting gasoline Natural 95.

  19. Numerical study on the combustion process of a biogas spark-ignition engine

    Directory of Open Access Journals (Sweden)

    Carrera José L.

    2013-01-01

    Full Text Available The fuel called biogas is obtained through anaerobic digestion of different types of organic waste, providing a way to tap the energy stored in organic matter. The use of this fuel is also attractive from the standpoint of global warming because its application does not register a net emission of carbon dioxide into the atmosphere. One possible use for this fuel is to feed the spark-ignition internal combustion engines. In the present, there is little information available about the process of combustion in internal combustion engines fueled by biogas. The combustion process of an internal combustion engine ignition powered by biogas is characterized in terms of the duration of combustion, i.e., depending on the time elapsed while the reactants (methane and oxygen are transformed into products (mainly carbon dioxide and water. This study numerically evaluates the way in which the geometrical parameters such as the compression ratio and operating parameters like engine speed, the excess air, the time of spark timing and carbon dioxide content of biogas affect the evolution of the combustion process. To carry out this study, a five factors and two levels experiment was designed and conducted, based on which, the most influential parameters were identified. Equations expressing the combustion characteristic parameters, as a function of the geometric and operation parameters of a spark ignited engines, are delivered as a result.

  20. Improving the performance and fuel consumption of dual chamber stratified charge spark ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Sorenson, S.C.; Pan, S.S.; Bruckbauer, J.J.; Gehrke, G.R.

    1979-09-01

    A combined experimental and theoretical investigation of the nature of the combustion processes in a dual chamber stratified charge spark ignition engine is described. This work concentrated on understanding the mixing process in the main chamber gases. A specially constructed single cylinder engine was used to both conduct experiments to study mixing effects and to obtain experimental data for the validation of the computer model which was constructed in the theoretical portion of the study. The test procedures are described. Studies were conducted on the effect of fuel injection timing on performance and emissions using the combination of orifice size and prechamber to main chamber flow rate ratio which gave the best overall compromise between emissions and performance. In general, fuel injection gave slightly higher oxides of nitrogen, but considerably lower hydrocarbon and carbon monoxide emissions than the carbureted form of the engine. Experiments with engine intake port redesign to promote swirl mixing indicated a substantial increase in the power output from the engine and, that an equivalent power levels, the nitric oxide emissions are approximately 30% lower with swirl in the main chamber than without swirl. The development of a computer simulation of the combustion process showed that a one-dimensional combustion model can be used to accurately predict trends in engine operation conditions and nitric oxide emissions even though the actual flame in the engine is not completely one-dimensional, and that a simple model for mixing of the main chamber and prechamber intake gases at the start of compression proved adequate to explain the effects of swirl, ignition timing, overall fuel air ratio, volumetric efficiency, and variations in prechamber air fuel ratio and fuel rate percentage on engine power and nitric oxide emissions. (LCL)

  1. Exhaust Emissions Measured Under Real Traffic Conditions from Vehicles Fitted with Spark Ignition and Compression Ignition Engines

    Science.gov (United States)

    Merkisz, Jerzy; Lijewski, Piotr; Fuć, Paweł

    2011-06-01

    The tests performed under real traffic conditions provide invaluable information on the relations between the engine parameters, vehicle parameters and traffic conditions (traffic congestion) on one side and the exhaust emissions on the other. The paper presents the result of road tests obtained in an urban and extra-urban cycles for vehicles fitted with different engines, spark ignition engine and compression ignition engine. For the tests a portable emission analyzer SEMTECH DS. by SENSORS was used. This analyzer provides online measurement of the concentrations of exhaust emission components on a vehicle in motion under real traffic conditions. The tests were performed in city traffic. A comparative analysis has been presented of the obtained results for vehicles with individual powertrains.

  2. Numerical investigation of natural gas direct injection properties and mixture formation in a spark ignition engine

    Directory of Open Access Journals (Sweden)

    Yadollahi Bijan

    2014-01-01

    Full Text Available In this study, a numerical model has been developed in AVL FIRE software to perform investigation of Direct Natural Gas Injection into the cylinder of Spark Ignition Internal Combustion Engines. In this regard two main parts have been taken into consideration, aiming to convert an MPFI gasoline engine to direct injection NG engine. In the first part of study multi-dimensional numerical simulation of transient injection process, mixing and flow field have been performed via three different validation cases in order to assure the numerical model validity of results. Adaption of such a modeling was found to be a challenging task because of required computational effort and numerical instabilities. In all cases present results were found to have excellent agreement with experimental and numerical results from literature. In the second part, using the moving mesh capability the validated model has been applied to methane Injection into the cylinder of a Direct Injection engine. Five different piston head shapes along with two injector types have been taken into consideration in investigations. A centrally mounted injector location has been adapted to all cases. The effects of injection parameters, combustion chamber geometry, injector type and engine RPM have been studied on mixing of air-fuel inside cylinder. Based on the results, suitable geometrical configuration for a NG DI Engine has been discussed.

  3. Artificial neural network applications in the calibration of spark-ignition engines: An overview

    Directory of Open Access Journals (Sweden)

    Richard Fiifi Turkson

    2016-09-01

    Full Text Available Emission legislation has become progressively tighter, making the development of new internal combustion engines very challenging. New engine technologies for complying with these regulations introduce an exponential dependency between the number of test combinations required for obtaining optimum results and the time and cost outlays. This makes the calibration task very expensive and virtually impossible to carry out. The potential use of trained neural networks in combination with Design of Experiments (DoE methods for engine calibration has been a subject of research activities in recent times. This is because artificial neural networks, compared with other data-driven modeling techniques, perform better in satisfying a majority of the modeling requirements for engine calibration including the curse of dimensionality; the use of DoE for obtaining few measurements as practicable, with the aim of reducing engine calibration costs; the required flexibility that allows model parameters to be optimized to avoid overfitting; and the facilitation of automated online optimization during the engine calibration process that eliminates the need for user intervention. The purpose of this review is to give an overview of the various applications of neural networks in the calibration of spark-ignition engines. The identified and discussed applications include system identification for rapid prototyping, virtual sensing, use of neural networks as look-up table surrogates, emerging control strategies and On-Board Diagnostic (OBD applications. The demerits of neural networks, future possibilities and alternatives were also discussed.

  4. Modelling of a Spark Ignition Engine for Power-Heat Production Optimization Modèle de moteur à allumage commandé en vue de l’optimisation de la production chaleur-force

    Directory of Open Access Journals (Sweden)

    Descieux D.

    2011-09-01

    Full Text Available Spark ignition gas engine is more and more used in order to produce electricity and heat simultaneously. The engine crankshaft drives a synchronous electric generator. The thermal power output is recovered from the engine coolant system and exhaust gas, and is used to produce generally hot water for heating system. In order to have a better adequacy between supply (production of the engine and user demand, good knowledge of the engine and implemented phenomena are necessary. A generic methodology is proposed to simulate the stationary state response of a SI engine. The engine simulation is based on a one zone thermodynamic model, which characterizes each phase of the engine cycle to predict energy performances: exergy efficiency as high as 0.70 is attainable. Le moteur a allumage commande alimente en gaz est un moteur de plus en plus utilise pour la production simultanee d’electricite et de chaleur. Classiquement le moteur entraine sur l’arbre une generatrice electrique. Le flux thermique est recupere principalement sur le systeme de refroidissement du moteur ainsi que sur les fumees chaudes et il est generalement utilise pour produire de la chaleur pour les systemes de chauffage. Pour avoir une meilleure adaptation entre la production du moteur et la demande de l’usager, une bonne connaissance des evolutions dans le moteur et des phenomenes correspondants est necessaire. Une methode thermodynamique generale est proposee pour simulation du fonctionnement dynamique stationnaire d’un MACI. Le modele utilise une analyse monozone et les caracteristiques de chaque transformation du cycle pour etudier les performances energetiques : rendement exergetique de l’ordre de 0,70.

  5. Heat transfer comparison between methane and hydrogen in a spark ignited engine

    Energy Technology Data Exchange (ETDEWEB)

    Sierens, Roger; Demuynck, Joachim; Paepe, Michel de; Verhelst, Sebastian [Ghent Univ. (Belgium)

    2010-07-01

    Hydrogen is one of the alternative fuels which are being investigated at Ghent University. NO{sub x} emissions will occur at high engine loads and they are a constraint for power and efficiency optimization. The formation of NO{sub x} emissions is temperature dependent. Consequently, the heat transfer from the burning gases to the cylinder walls has to be accurately modelled if precise computer calculations of the emissions are wanted. Several engine heat transfer models exist but they have been cited to be inaccurate for hydrogen. We have measured the heat flux in a spark ignited engine with a commercially available heat flux sensor. This paper investigates the difference between the heat transfer of hydrogen and a fossil fuel, in this case methane. Measurements with the same indicated power output are compared and the effect of the heat loss on the indicated efficiency is investigated. The power output of hydrogen combustion is lowered by burning lean in contrast to using a throttle in the case of methane. Although the peak in the heat flux of hydrogen is 3 times higher compared to methane for a high engine power output, the indicated efficiency is only 3% lower. The heat loss for hydrogen at a low engine load is smaller than that of methane which results in a higher indicated efficiency. The richness of the hydrogen-air mixture has a great influence on the heat transfer process in contrast to the in-cylinder mass in the case of methane. (orig.)

  6. Developing a Knock Predictive Criterion in Spark Ignition Engines Fuelled with Gaseous Fuels

    Institute of Scientific and Technical Information of China (English)

    G.A.Karim

    1993-01-01

    Consideration of the chemical reaction activity of the end gas in a spark ignition and operating conditions are combined to predict the onset of knock and associated performance in an engine fuelled with methane.A two-zone predictive combustion model was developed based on an estimate of the effective duration of the combustion period and the mass burning rate for any set of operating conditions.The unburned end gas preignition chemical reaction activity is described by a detailed chemical reaction kinetic scheme for methane and air,The variation with time of the value of a formulated dimensionless knock parameter(k)is calcuated.It is shown that whenever knocking is encounteren.the value of “k” builds up to a sufficiently high value that exceeds a critical value.Under normal operating conditions,the value of “k” remains throughout the whole combustion period at comparatively very low levels.It is shown that the model and the use of this knock criterion“k” produce results that are in good agreement with experiment.

  7. Variations in speciated emissions from spark-ignition and compression-ignition motor vehicles in California's south coast air basin.

    Science.gov (United States)

    Fujita, Eric M; Zielinska, Barbara; Campbell, David E; Arnott, W Patrick; Sagebiel, John C; Mazzoleni, Lynn; Chow, Judith C; Gabele, Peter A; Crews, William; Snow, Richard; Clark, Nigel N; Wayne, W Scott; Lawson, Douglas R

    2007-06-01

    The U.S. Department of Energy Gasoline/Diesel PM Split Study examined the sources of uncertainties in using an organic compound-based chemical mass balance receptor model to quantify the contributions of spark-ignition (SI) and compression-ignition (CI) engine exhaust to ambient fine particulate matter (PM2.5). This paper presents the chemical composition profiles of SI and CI engine exhaust from the vehicle-testing portion of the study. Chemical analysis of source samples consisted of gravimetric mass, elements, ions, organic carbon (OC), and elemental carbon (EC) by the Interagency Monitoring of Protected Visual Environments (IMPROVE) and Speciation Trends Network (STN) thermal/optical methods, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, alkanes, and polar organic compounds. More than half of the mass of carbonaceous particles emitted by heavy-duty diesel trucks was EC (IMPROVE) and emissions from SI vehicles contained predominantly OC. Although total carbon (TC) by the IMPROVE and STN protocols agreed well for all of the samples, the STN/IMPROVE ratios for EC from SI exhaust decreased with decreasing sample loading. SI vehicles, whether low or high emitters, emitted greater amounts of high-molecular-weight particulate PAHs (benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, and coronene) than did CI vehicles. Diesel emissions contained higher abundances of two- to four-ring semivolatile PAHs. Diacids were emitted by CI vehicles but are also prevalent in secondary organic aerosols, so they cannot be considered unique tracers. Hopanes and steranes were present in lubricating oil with similar composition for both gasoline and diesel vehicles and were negligible in gasoline or diesel fuels. CI vehicles emitted greater total amounts of hopanes and steranes on a mass per mile basis, but abundances were comparable to SI exhaust normalized to TC emissions within measurement uncertainty. The combustion-produced high-molecular-weight PAHs were found in used

  8. DEVELOPING OF A NEW COMPREHENSIVE SPARK IGNITION ENGINES CODE FOR HEAT LOSS ANALYSIS WITHIN COMBUSTION CHAMBER WALLS

    Directory of Open Access Journals (Sweden)

    Shahram Khalilarya

    2010-01-01

    Full Text Available The objective of this work is to develop the existing a zero-dimensional model named ODES to provide detailed insights into the internal process of the modern high speed spark ignition engines. Therefore, it has been concentrated on the development of new sub models for incorporation in an extended form of ODES, as follows: - the existing semi-empirical combustion model has been replaced by a new comprehensive model, which is based on the turbulent flame speed in the combustion chamber. - the existing three wall heat transfer model has been replaced by a new one in which, the combustion chamber is divided in to three zones including cylinder head, cylinder wall, and piston head. The steady-state heat transfer equation is solved through finite difference method with replaced boundary and initial conditions. The results gave the temperature distribution of combustion chamber walls. The rate of heat losses from combustion chamber to the coolant is calculated by using the mean temperature of each part. The code has been extensively validated with respect to performance and heat transfer against experimental results obtained on XU7JP spark ignition engine with two kinds of fuel, gasoline and compresed natural gas and gave good agreement with available experimental.

  9. Efficiency characteristics of a new quasi-constant volume combustion spark ignition engine

    Directory of Open Access Journals (Sweden)

    Dorić Jovan Ž.

    2013-01-01

    Full Text Available A zero dimensional model has been used to investigate the combustion performance of a four cylinder petrol engine with unconventional piston motion. The main feature of this new spark ignition (SI engine concept is the realization of quasi-constant volume (QCV during combustion process. Presented mechanism is designed to obtain a specific motion law which provides better fuel consumption of internal combustion (IC engines. These advantages over standard engine are achieved through synthesis of unconventional piston mechanism. The numerical calculation was performed for several cases of different piston mechanism parameters, compression ratio and engine speed. Calculated efficiency and power diagrams are plotted and compared with performance of ordinary SI engine. The results show that combustion during quasi-constant volume has significant impact on improvement of efficiency. The main aim of this paper is to find a proper kinematics parameter of unconventional piston mechanism for most efficient heat addition in SI engines.[Acknowledgment. This research was done as a part of project TR31046 "Improvement of the quality of tractors and mobile systems with the aim of increasing competitiveness and preserving soil and environment", supported by Serbian Ministry of Science and Technological Development.

  10. PETN ignition experiments and models.

    Science.gov (United States)

    Hobbs, Michael L; Wente, William B; Kaneshige, Michael J

    2010-04-29

    Ignition experiments from various sources, including our own laboratory, have been used to develop a simple ignition model for pentaerythritol tetranitrate (PETN). The experiments consist of differential thermal analysis, thermogravimetric analysis, differential scanning calorimetry, beaker tests, one-dimensional time to explosion tests, Sandia's instrumented thermal ignition tests (SITI), and thermal ignition of nonelectrical detonators. The model developed using this data consists of a one-step, first-order, pressure-independent mechanism used to predict pressure, temperature, and time to ignition for various configurations. The model was used to assess the state of the degraded PETN at the onset of ignition. We propose that cookoff violence for PETN can be correlated with the extent of reaction at the onset of ignition. This hypothesis was tested by evaluating metal deformation produced from detonators encased in copper as well as comparing postignition photos of the SITI experiments.

  11. Conversion of a diesel engine to a spark ignition natural gas engine

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    Requirements for alternatives to diesel-fueled vehicles are developing, particularly in urban centers not in compliance with mandated air quality standards. An operator of fleets of diesel- powered vehicles may be forced to either purchase new vehicles or equip some of the existing fleets with engines designed or modified to run on alternative fuels. In converting existing vehicles, the operator can either replace the existing engine or modify it to burn an alternative fuel. Work described in this report addresses the problem of modifying an existing diesel engine to operate on natural gas. Tecogen has developed a technique for converting turbocharged automotive diesel engines to operate as dedicated spark-ignition engines with natural gas fuel. The engine cycle is converted to a more-complete-expansion cycle in which the expansion ratio of the original engine is unchanged while the effective compression ratio is lowered, so that engine detonation is avoided. The converted natural gas engine, with an expansion ratio higher than in conventional spark- ignition natural gas engines, offers thermal efficiency at wide-open- throttle conditions comparable to its diesel counterpart. This allows field conversion of existing engines. Low exhaust emissions can be achieved when the engine is operated with precise control of the fuel air mixture at stoichiometry with a 3-way catalyst. A Navistar DTA- 466 diesel engine with an expansion ratio of 16.5 to 1 was converted in this way, modifying the cam profiles, increasing the turbocharger boost pressure, incorporating an aftercooler if not already present, and adding a spark-ignition system, natural gas fuel management system, throttle body for load control, and an electronic engine control system. The proof-of-concept engine achieved a power level comparable to that of the diesel engine without detonation. A conversion system was developed for the Navistar DT 466 engine. NOx emissions of 1.5 g/bhp-h have been obtained.

  12. An assessment of combustion products of spark ignition engines supplied by ethanol - gasoline blends

    Science.gov (United States)

    Uzuneanu, K.; Golgotiu, E.

    2016-08-01

    The causes of environmental pollution by internal combustion engines arise from the use of fuels containing bounded carbon, from the fact that combustion takes place on a cyclic basis and at high temperature. The first and the last causes are directly related to the fuel and therefore there is in principle a possibility to reduce pollution by acting upon the fuel used. The present paper deals with the comparison of the level of combustion products of a spark ignition engine supplied by gasoline and by a mixture of 10 % ethanol - 90% gasoline.

  13. Performance and emissions analysis on using acetone–gasoline fuel blends in spark-ignition engine

    OpenAIRE

    2016-01-01

    In this study, new blended fuels were formed by adding 3–10 vol. % of acetone into a regular gasoline. According to the best of the author's knowledge, it is the first time that the influence of acetone blends has been studied in a gasoline-fueled engine. The blended fuels were tested for their energy efficiencies and pollutant emissions using SI (spark-ignition) engine with single-cylinder and 4-stroke. Experimental results showed that the AC3 (3 vol.% acetone + 97 vol.% gasoline) blended fu...

  14. Different Boosting Systems and their Control Strategies for a Spark Ignition Internal Combustion Engine

    Directory of Open Access Journals (Sweden)

    Bolehovský Ondřej

    2016-06-01

    Full Text Available This research uses 1-D simulation in GT-Power for evaluation of boosting systems for a spark ignition engine. Exhaust gas driven (waste-gated turbocharger and mechanical driven (Roots blower boosting systems are assessed in both steady state and transient modes in terms of performance, efficiency, fuel consumption, drivability, energy distribution and other aspects that influence gas exchange phase. Moreover, different boost control strategies, particularly at partial load, are also evaluated. Results of the research are aimed at helping identify an optimal boosting system for standardized or real-world drive cycles.

  15. Report on Investigation of Alcohol Combustion Associated Wear in Spark Ignition Engines, Mechanisms and Lubricant Effects.

    Science.gov (United States)

    1984-12-01

    Combustion Associated Wear in Spark-Ignition Enzines 12. PERSONAL AUTHORISI INaegeli, David N. and Owens, Edwin C. 131. TYPE OF REPORT 13b. TIME COVERED 114...READINESS CMD ATTN: STEYP-MLS-M (MR DOEBBLER) I -. ATTN: AMSAR-LEM 1 YUMA AZ 85364 ROCK ISLAND ARSENAL IL 61299 PROJ MGR, BRADELY FIGHTING - CDR...CHIEF OF NAVAL RESEARCH CDR ATTN: CODE 473 1 DAVID TAYLOR NAVAL SHIP R&D CTR ARLINGTON VA 22217 ATTN: CODE 2830 (MR G BOSMAJIAN) 1 CODE 2705.1 (MR

  16. Qualification of numerical software. Application to a Software for analyzing combustion in spark-ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Guilain, S. (Agence de l' Environnement et de la Maitrise de l' Energie, 75 - Paris (France) Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France) Ecole Nationale Superieure du Petrole et des Moteurs (ENSPM), 92 - Rueil-Malmaison (France)); Vignes, J. (Paris-6 Univ., 75 (France) Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France))

    For analyzing physical phenomena, numerical simulation is used more and more frequently. Starting with a mathematical model describing the phenomenon being analyzed, this simulation consists in creating a scientific computing program expressing this model by implementing the numerical methods required for solving it. Simulation is considered to be valid when the results its provides are in agreement with the results issuing from experimenting with the phenomenon. However, these results contain a computing error resulting from the propagation of round-off errors caused by the floating-point arithmetic used by the computer. They also contain an error coming from the uncertainties concerning the data of the problem. The first part of this paper concerns the validation of numerical software results. After making a brief review of the floating-point arithmetic and highlighting the serious consequences it may have on the results obtained, a probabilistic approach to the analysis of round-off errors, the CESTAC (Controle et Estimation STochastique des Arrondis de Calculs) method, from the standpoint of both its theoretical bases and its practical implementation is described. The second part is devoted to the use of the CADNA software (Control of Accuracy and Debugging for Numerical Applications) for qualifying the simulation software, ANALCO (ANALyse de COmbustion) which analyses combustion in spark-ignition engines. After a description of the normal model of the phenomenon being analyzed and after mathematical model has been deduced, the ANALCO simulation software is described. The results obtained with ANALCO, not using CADNA, reveal the disagreement between the simulation results and the experimental results. The use of the CADNA software eliminates the numerical instabilities and demonstrates that the disagreement between the simulation results and the results observed is due only to numerical problems. (author). 22 refs., 21 figs., 10 tabs.

  17. Internal combustion engine report: Spark ignited ICE GenSet optimization and novel concept development

    Energy Technology Data Exchange (ETDEWEB)

    Keller, J.; Blarigan, P. Van [Sandia National Labs., Livermore, CA (United States)

    1998-08-01

    In this manuscript the authors report on two projects each of which the goal is to produce cost effective hydrogen utilization technologies. These projects are: (1) the development of an electrical generation system using a conventional four-stroke spark-ignited internal combustion engine generator combination (SI-GenSet) optimized for maximum efficiency and minimum emissions, and (2) the development of a novel internal combustion engine concept. The SI-GenSet will be optimized to run on either hydrogen or hydrogen-blends. The novel concept seeks to develop an engine that optimizes the Otto cycle in a free piston configuration while minimizing all emissions. To this end the authors are developing a rapid combustion homogeneous charge compression ignition (HCCI) engine using a linear alternator for both power take-off and engine control. Targeted applications include stationary electrical power generation, stationary shaft power generation, hybrid vehicles, and nearly any other application now being accomplished with internal combustion engines.

  18. Comparison of Waste Heat Recovery from the Exhaust of a Spark Ignition and a Diesel Engine

    Science.gov (United States)

    Wojciechowski, K. T.; Schmidt, M.; Zybala, R.; Merkisz, J.; Fuć, P.; Lijewski, P.

    2010-09-01

    We present herein a design for and performance measurements of a prototype thermoelectric generator (TEG) mounted on both a spark ignition engine (0.9 dm3) and a self-ignition engine (1.3 dm3). Using the prototype TEG as a tool, benchmark studies were performed in order to compare its parameters in terms of heat recovery from exhaust gases of both engine types. The test bed study was performed with an Automex AMX-210/100 eddy-current brake dynamometer. To provide a comprehensive overview of the TEG operating conditions, characterization of its parameters such as temperature distribution, heat flux density, and efficiency was done at engine speeds and loads similar to those within the range of operation of real road conditions.

  19. Spark Ignition Engine Combustion, Performance and Emission Products from Hydrous Ethanol and Its Blends with Gasoline

    Directory of Open Access Journals (Sweden)

    Musaab O. El-Faroug

    2016-11-01

    Full Text Available This paper reviews the serviceability of hydrous ethanol as a clean, cheap and green renewable substitute fuel for spark ignition engines and discusses the comparative chemical and physical properties of hydrous ethanol and gasoline fuels. The significant differences in the properties of hydrous ethanol and gasoline fuels are sufficient to create a significant change during the combustion phase of engine operation and consequently affect the performance of spark-ignition (SI engines. The stability of ethanol-gasoline-water blends is also discussed. Furthermore, the effects of hydrous ethanol, and its blends with gasoline fuel on SI engine combustion characteristics, cycle-to-cycle variations, engine performance parameters, and emission characteristics have been highlighted. Higher water solubility in ethanol‑gasoline blends may be obviously useful and suitable; nevertheless, the continuous ability of water to remain soluble in the blend is significantly affected by temperature. Nearly all published engine experimental results showed a significant improvement in combustion characteristics and enhanced engine performance for the use of hydrous ethanol as fuel. Moreover, carbon monoxide and oxides of nitrogen emissions were also significantly decreased. It is also worth pointing out that unburned hydrocarbon and carbon dioxide emissions were also reduced for the use of hydrous ethanol. However, unregulated emissions such as acetaldehyde and formaldehyde were significantly increased.

  20. Effect of Inhibitors on Biogas Laminar Burning Velocity and Flammability Limits in Spark Ignited Premix Combustion

    Directory of Open Access Journals (Sweden)

    Willyanto Anggono

    2014-01-01

    Full Text Available Biogas is the natural byproduct of the decomposition of vegetation or animal manure, of which there are almost in exhaustable supplies in the world, and which does not contribute CO2 or other greenhouse gases to global warming or climate change. Biogas contains 66.4% flammable gas (CH4 and 33.6% inhibitors (CO2 and N2. This study focuses on the effects of inhibitors on biogas laminar burning velocity and flammability limits in spark ignited premix combustion. Spherically expanding laminar premixed flames, freely propagating from spark ignition sources in initially quiescent biogas–air mixtures, are continuously recorded by a high-speed digital camera. Initially, all the experiments in this paper were performed using inhibitorless biogas (biogas without inhibitors at room temperature, at reduced pressure (0.5 atm and at various equivalence ratios (ϕ from the lower flammable limit to the upper flammable limit. The results are compared with those from biogas (containing inhibitors flames at reduced pressure, inhibitorless biogas flames at atmospheric pressure (1 atm, and biogas flames at atmospheric pressure to emphasize the effect of inhibitors on biogas laminar burning velocity and flammability limits. Compared to an inhibitorless biogas-air mixtures, in the biogas-air mixtures, the presence of inhibitors cause a reduction in the laminar burning velocity and the flammable limits become narrower.

  1. 40 CFR Table 1a to Subpart Zzzz of... - Emission Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE...

    Science.gov (United States)

    2010-07-01

    ... pursuant to the requirements of 40 CFR 63.6(g) for alternative work practices. ..., and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a Major Source of HAP... Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at...

  2. 40 CFR Table 1b to Subpart Zzzz of... - Operating Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE...

    Science.gov (United States)

    2010-07-01

    ..., New, and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a Major Source of HAP... Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a... stationary RICE complying with the requirement to reduce formaldehyde emissions by 76 percent or more (or...

  3. A Laser Spark Plug Ignition System for a Stationary Lean-Burn Natural Gas Reciprocating Engine

    Energy Technology Data Exchange (ETDEWEB)

    McIntyre, D. L. [West Virginia Univ., Morgantown, WV (United States)

    2007-05-01

    To meet the ignition system needs of large bore, high pressure, lean burn, natural gas engines a side pumped, passively Q-switched, Nd:YAG laser was developed and tested. The laser was designed to produce the optical intensities needed to initiate ignition in a lean burn, high compression engine. The laser and associated optics were designed with a passive Q-switch to eliminate the need for high voltage signaling and associated equipment. The laser was diode pumped to eliminate the need for high voltage flash lamps which have poor pumping efficiency. The independent and dependent parameters of the laser were identified and explored in specific combinations that produced consistent robust sparks in laboratory air. Prior research has shown that increasing gas pressure lowers the breakdown threshold for laser initiated ignition. The laser has an overall geometry of 57x57x152 mm with an output beam diameter of approximately 3 mm. The experimentation used a wide range of optical and electrical input parameters that when combined produced ignition in laboratory air. The results show a strong dependence of the output parameters on the output coupler reflectivity, Q-switch initial transmission, and gain media dopant concentration. As these three parameters were lowered the output performance of the laser increased leading to larger more brilliant sparks. The results show peak power levels of up to 3MW and peak focal intensities of up to 560 GW/cm2. Engine testing was performed on a Ricardo Proteus single cylinder research engine. The goal of the engine testing was to show that the test laser performs identically to the commercially available flashlamp pumped actively Q-switched laser used in previous laser ignition testing. The engine testing consisted of a comparison of the in-cylinder, and emissions behavior of the engine using each of the lasers as an ignition system. All engine parameters were kept as constant as possilbe while the equivalence ratio (fueling

  4. Analysis of biomass and waste gasification lean syngases combustion for power generation using spark ignition engines.

    Science.gov (United States)

    Marculescu, Cosmin; Cenuşă, Victor; Alexe, Florin

    2016-01-01

    The paper presents a study for food processing industry waste to energy conversion using gasification and internal combustion engine for power generation. The biomass we used consisted in bones and meat residues sampled directly from the industrial line, characterised by high water content, about 42% in mass, and potential health risks. Using the feedstock properties, experimentally determined, two air-gasification process configurations were assessed and numerically modelled to quantify the effects on produced syngas properties. The study also focused on drying stage integration within the conversion chain: either external or integrated into the gasifier. To comply with environmental regulations on feedstock to syngas conversion both solutions were developed in a closed system using a modified down-draft gasifier that integrates the pyrolysis, gasification and partial oxidation stages. Good quality syngas with up to 19.1% - CO; 17% - H2; and 1.6% - CH4 can be produced. The syngas lower heating value may vary from 4.0 MJ/Nm(3) to 6.7 MJ/Nm(3) depending on process configuration. The influence of syngas fuel properties on spark ignition engines performances was studied in comparison to the natural gas (methane) and digestion biogas. In order to keep H2 molar quota below the detonation value of ⩽4% for the engines using syngas, characterised by higher hydrogen fraction, the air excess ratio in the combustion process must be increased to [2.2-2.8]. The results in this paper represent valuable data required by the design of waste to energy conversion chains with intermediate gas fuel production. The data is suitable for Otto engines characterised by power output below 1 MW, designed for natural gas consumption and fuelled with low calorific value gas fuels.

  5. Laser-induced spark ignition of H2/O2/Ar mixtures

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Laser-induced spark ignition of hydrogen-oxygen-argon mixtures was experimentally investigated using a Q-swiched Nd:YAG laser to break down the gas at 532 nm. The laser-based high-speed schlieren system was employed to record flame front evolution for the gas mixtures with different initial pressure or laser output energy or argon dilution. The results show that the breakdown of the gas leads to the generation of ellipsoidal plasma. The rarefaction waves create the toroidal rings at the leading and trailing edges of the plasma, which provides a reasonable explanation for inward wrinkle of the plasma and the resultant flame. The toroidal rings at leading edge decays more rapidly and a gas lobe is generated that moves towards the laser. The hot gas in the plasma induces the generation of the spark kernel. Affected by the very weak shock wave or compression waves reflected off the wall, the initial laminar flame decelerates. The arc flame front interactions with the wall, reversed shock wave or compression waves, rarefaction waves, etc. induce the transition from laminar flame to turbulent one. These induce the transition from laminar flame to turbulent flame. For stoichiometric hydrogen-oxygen mixtures diluted by 76.92% argon at an initial pressure of 53.33 kPa, the minimum output energy of the laser is 15 mJ for successful laser-induced spark ignition. With increasing initial pressure or the output energy of the laser, or decreasing argon dilution, the speed of the flame front increases.

  6. Spectroscoping analysis of ignition in a spark ignition engine with jet-controlled combustion; Spektroskopische Untersuchung der Entflammung an einem Ottomotor mit strahlgefuehrtem Brennverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Palaveev, S. [MOT Forschungs- und Entwicklungsgesellschaft fuer Motorentechnik, Optik und Thermodynamik GmbH, Karlsruhe (Germany); Buri, S.; Xander, B.; Spicher, U. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Kolbenmaschinen

    2007-07-01

    The gasoline direct injection engine is one of the most promising strategies today to reduce the fuel consumption and CO{sub 2}-emissions of spark-ignition engines. The commercial launch of that combustion system was possible only through the development of new optical measurement techniques, which have been a major contribution for understanding the basics of the combustion in a stratified mode. In terms of space and time, compared to the homogeneous approach, the air-fuel-ratio for a stratified mode may vary significantly. This fluctuation affects in a critical way the process of ignition and combustion. The knowledge of the air-fuel-ratio in the spark plug area both at time of ignition and in during the combustion is therefore critical for the development of this combustion system and it components. This paper presents the spark-emission spectroscopy as a non invasive optical technique for measuring the air-fuel-ratio {lambda} in the spark gap at time of ignition. (orig.)

  7. Development of laser-induced fluorescence for precombustion diagnostics in spark-ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Neij, H.

    1998-11-01

    Motivated by a desire to understand and optimize combustion in spark-ignition (SI) engines, laser techniques have been developed for measurement of fuel and residual gas, respectively, in the precombustion mixture of an operating SI engine. The primary objective was to obtain two-dimensional, quantitative data in the vicinity of the spark gap at the time of ignition. A laser-induced fluorescence (LIF) technique was developed for fuel visualization in engine environments. Since the fluorescence signal from any commercial gasoline fuel would be unknown to its origin, with an unpredictable dependence on collisional partners, pressure and temperature, a non-fluorescent base fuel - isooctane - was used. For LIF detection, a fluorescent species was added to the fuel. An additive not commonly used in this context - 3-pentanone - was chosen based on its suitable vaporization characteristics and fluorescent properties. The LIF technique was applied to an optically accessible research engine. By calibration, the fluorescence signal from the additive was converted to fuel-to-air equivalence ratio ({phi}). The accuracy and precision of the acquired data were assessed. A statistical evaluation revealed that the spatially averaged equivalence ratio around the spark plug had a significant impact on the combustion event. The strong correlation between these two quantities suggested that the early combustion was sensitive to large-scale inhomogeneities in the precombustion mixture. A similar LIF technique, using acetone as a fluorescent additive in methane, was applied to a combustion cell for ion current evaluation. The local equivalence ratio around the spark gap at the time of ignition was extracted from LIF data. Useful relations were identified between different ion current parameters and the local equivalence ratio, although the impact of the flow field, the fuel type, and the electrode geometry were identified as areas for future research. A novel fuel - dimethyl ether (DME

  8. Development of laser-induced fluorescence for precombustion diagnostics in spark-ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Neij, H.

    1998-11-01

    Motivated by a desire to understand and optimize combustion in spark-ignition (SI) engines, laser techniques have been developed for measurement of fuel and residual gas, respectively, in the precombustion mixture of an operating SI engine. The primary objective was to obtain two-dimensional, quantitative data in the vicinity of the spark gap at the time of ignition. A laser-induced fluorescence (LIF) technique was developed for fuel visualization in engine environments. Since the fluorescence signal from any commercial gasoline fuel would be unknown to its origin, with an unpredictable dependence on collisional partners, pressure and temperature, a non-fluorescent base fuel - isooctane - was used. For LIF detection, a fluorescent species was added to the fuel. An additive not commonly used in this context - 3-pentanone - was chosen based on its suitable vaporization characteristics and fluorescent properties. The LIF technique was applied to an optically accessible research engine. By calibration, the fluorescence signal from the additive was converted to fuel-to-air equivalence ratio ({phi}). The accuracy and precision of the acquired data were assessed. A statistical evaluation revealed that the spatially averaged equivalence ratio around the spark plug had a significant impact on the combustion event. The strong correlation between these two quantities suggested that the early combustion was sensitive to large-scale inhomogeneities in the precombustion mixture. A similar LIF technique, using acetone as a fluorescent additive in methane, was applied to a combustion cell for ion current evaluation. The local equivalence ratio around the spark gap at the time of ignition was extracted from LIF data. Useful relations were identified between different ion current parameters and the local equivalence ratio, although the impact of the flow field, the fuel type, and the electrode geometry were identified as areas for future research. A novel fuel - dimethyl ether (DME

  9. Some aspects of the CI engine modification aimed at operation on LPG with the application of spark ignition

    Science.gov (United States)

    Kaparuk, J.; Luft, S.; Skrzek, T.; Wojtyniak, M.

    2016-09-01

    A lot of investigation on modification of the compression ignition engine aimed at operation on LPG with the application of spark ignition has been carried out in the Laboratory of Vehicles and Combustion Engines at Kazimierz Pulaski University of Technology and Humanities in Radom. This paper presents results of investigation on establishment of the proper ignition advance angle in the modified engine. Within the framework of this investigation it was assessed the effect of this regulation on basic engine operating parameters, exhaust emission as well as basic combustion parameters.

  10. Estimation of operational parameters for a direct injection turbocharged spark ignition engine by using regression analysis and artificial neural network

    Directory of Open Access Journals (Sweden)

    Tosun Erdi

    2017-01-01

    Full Text Available This study was aimed at estimating the variation of several engine control parameters within the rotational speed-load map, using regression analysis and artificial neural network techniques. Duration of injection, specific fuel consumption, exhaust gas at turbine inlet, and within the catalytic converter brick were chosen as the output parameters for the models, while engine speed and brake mean effective pressure were selected as independent variables for prediction. Measurements were performed on a turbocharged direct injection spark ignition engine fueled with gasoline. A three-layer feed-forward structure and back-propagation algorithm was used for training the artificial neural network. It was concluded that this technique is capable of predicting engine parameters with better accuracy than linear and non-linear regression techniques.

  11. A Soft Sensor-Based Fault-Tolerant Control on the Air Fuel Ratio of Spark-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Yu-Jia Zhai

    2017-01-01

    Full Text Available The air/fuel ratio (AFR regulation for spark-ignition (SI engines has been an essential and challenging control problem for engineers in the automotive industry. The feed-forward and feedback scheme has been investigated in both academic research and industrial application. The aging effect can often cause an AFR sensor fault in the feedback loop, and the AFR control performance will degrade consequently. In this research, a new control scheme on AFR with fault-tolerance is proposed by using an artificial neural network model based on fault detection and compensation, which can provide the satisfactory AFR regulation performance at the stoichiometric value for the combustion process, given a certain level of misreading of the AFR sensor.

  12. Development of High Efficiency Clean Combustion Engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, Craig; Gonzalez, Manual; Russell, Durrett

    2011-06-30

    This report summarizes activities related to the revised STATEMENT OF PROJECT OBJECTIVES (SOPO) dated June 2010 for the Development of High-Efficiency Clean Combustion engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines (COOPERATIVE AGREEMENT NUMBER DE-FC26-05NT42415) project. In both the spark- (SI) and compression-ignition (CI) development activities covered in this program, the goal was to develop potential production-viable internal combustion engine system technologies that both reduce fuel consumption and simultaneously met exhaust emission targets. To be production-viable, engine technologies were also evaluated to determine if they would meet customer expectations of refinement in terms of noise, vibration, performance, driveability, etc. in addition to having an attractive business case and value. Prior to this activity, only proprietary theoretical / laboratory knowledge existed on the combustion technologies explored The research reported here expands and develops this knowledge to determine series-production viability. Significant SI and CI engine development occurred during this program within General Motors, LLC over more than five years. In the SI program, several engines were designed and developed that used both a relatively simple multi-lift valve train system and a Fully Flexible Valve Actuation (FFVA) system to enable a Homogeneous Charge Compression Ignition (HCCI) combustion process. Many technical challenges, which were unknown at the start of this program, were identified and systematically resolved through analysis, test and development. This report documents the challenges and solutions for each SOPO deliverable. As a result of the project activities, the production viability of the developed clean combustion technologies has been determined. At this time, HCCI combustion for SI engines is not considered production-viable for several reasons. HCCI combustion is excessively sensitive to control variables

  13. Effects of Waste Plastic Oil Blends on a Multi Cylinder Spark Ignition Engine

    Directory of Open Access Journals (Sweden)

    Vijaya Kumar Kareddula

    2017-01-01

    Full Text Available Existing fossil fuels are utilizing at their critical rate, leads to depletion of their reserves in a dramatic way. Generating alternative energy sources in a pragmatic way are necessitated, which demands the researchers to utilize the inherent energy of carbon based products as an energy source to the automobile sector. As a part of it, my research is focused on transforming and using the waste plastics as an alternative fuel in multi cylinder spark ignition engine. This paper aims to present the experimental investigations of performance and emission characteristics in an existing Maruti 800 petrol engine running with the blends of 5%, 10%, 15% and 20% of waste Plastic Pyrolysis Oil (PPO with gasoline. From the results, it is noticed that hydrocarbon emissions are substantially reduced and oxides of nitrogen emissions are increased and petrol engine can operate with PPO blends up to 20% without any engine modifications.

  14. Adaptive Control Strategy for Dual–Fuel Stationary Spark Ignition Engines

    Directory of Open Access Journals (Sweden)

    Adrian Irimescu

    2011-10-01

    Full Text Available Fuel availability is an issue that will become ever more important in the future. Therefore, fuel systems will be required to ensure proper operation with a variety of fuel types. The main idea of this study is to develop a control strategy that ensures high fuel conversion efficiency and low emissions levels when employing dual–fuel operation in a micro–cogeneration installation powered by a spark ignition engine. Biogas was considered as the main fuel, while liquid fuel is used to compensate for eventual variations in the gaseous fuel flow. Stoichiometric air-fuel ratio is required at all times so that a three way catalytic converter can be used to simultaneously reduce carbon monoxide, unburned hydrocarbon and nitrogen oxide emissions.

  15. Efficiency and exhaust gas analysis of variable compression ratio spark ignition engine fuelled with alternative fuels

    Directory of Open Access Journals (Sweden)

    N. Seshaiah

    2010-09-01

    Full Text Available Considering energy crises and pollution problems today, investigations have been concentrated on decreasing fuel consumption by using alternative fuels and on lowering the concentration of toxic components in combustion products. In the present work, the variable compression ratio spark ignition engine designed to run on gasoline has been tested with pure gasoline, LPG (Isobutene, and gasoline blended with ethanol 10%, 15%, 25% and 35% by volume. Also, the gasoline mixed with kerosene at 15%, 25% and 35% by volume without any engine modifications has been tested and presented the result. Brake thermal and volumetric efficiency variation with brake load is compared and presented. CO and CO2 emissions have been also compared for all tested fuels.

  16. Full Load Performance of a Spark Ignition Engine Fueled with Gasoline-Isobutanol Blends

    Directory of Open Access Journals (Sweden)

    Adrian Irimescu

    2009-10-01

    Full Text Available With fossil fuels reserves coming ever closer to depletion and the issue of air pollution caused by automotive transport becoming more and more important, mankind has looked for various solutions in the field of internal combustion engines. One of these solutions is using biofuels, and while the internal combustion engine will most likely disappear along with the last fossil fuel source, studying biofuels and their impact on automotive power-trains is a necessity even if only on a the short term basis. While engines built to run on alcohol-gasoline blends offer good performance levels even at high concentrations of alcohol, unmodified engines fueled with blends of biofuels and fossil fuels can exhibit a drop in power. The object of this study is evaluating such phenomena when a spark ignition engine is operated at full load.

  17. "Simultaneous measurement of flame impingement and piston surface temperatures in an optically accessible spark ignition engine"

    Science.gov (United States)

    Ding, Carl-Philipp; Honza, Rene; Böhm, Benjamin; Dreizler, Andreas

    2017-04-01

    This paper shows the results of spatially resolved temperature measurements of the piston surface of an optically accessible direct injection spark ignition engine during flame impingement. High-speed thermographic phosphor thermometry (TPT), using Gd3Ga5O12:Cr,Ce, and planar laser-induced fluorescence of the hydroxyl radical (OH-PLIF) were used to investigate the temperature increase and the time and position of flame impingement at the piston surface. Measurements were conducted at two operating cases and showed heating rates of up to 16,000 K/s. The OH-PLIF measurements were used to localize flame impingement and calculate conditioned statistics of the temperature profiles. The TPT coating was characterized and its influence on the temperature measurements evaluated.

  18. Exhaust emissions of methanol and ethanol-unleaded gasoline blends in a spark-ignition engine

    Directory of Open Access Journals (Sweden)

    Altun Şehmus

    2013-01-01

    Full Text Available In this study, the effect of unleaded gasoline and unleaded gasoline blended with 5% and 10% of ethanol or methanol on the performance and exhaust emissions of a spark-ignition engine were experimentally investigated. The engine tests were performed by varying the engine speed between 1000 and 4000 rpm with 500 rpm period at threefourth throttle opening position. The results showed that brakespecific fuel consumption increased while brake thermal efficiency, emissions of carbon monoxide (CO and hydrocarbon (HCs decreased with methanol-unleaded gasoline and ethanol-unleaded gasoline blends. It was found that a 10% blend of ethanol or methanol with unleaded gasoline works well in the existing design of engine and parameters at which engines are operating.

  19. Onboard Hydrogen Generation for a Spark Ignition Engine via Thermochemical Recuperation

    Science.gov (United States)

    Silva, Isaac Alexander

    A method of exhaust heat recovery from a spark-ignition internal combustion engine was explored, utilizing a steam reforming thermochemical reactor to produce a hydrogen-rich effluent, which was then consumed in the engine. The effects of hydrogen in the combustion process have been studied extensively, and it has been shown that an extension of the lean stability limit is possible through hydrogen enrichment. The system efficiency and the extension of the operational range of an internal combustion engine were explored through the use of a methane fueled naturally aspirated single cylinder engine co-fueled with syngas produced with an on board methane steam reformer. It was demonstrated that an extension of the lean stability limit is possible using this system.

  20. Performance and emissions analysis on using acetone–gasoline fuel blends in spark-ignition engine

    Directory of Open Access Journals (Sweden)

    Ashraf Elfasakhany

    2016-09-01

    Full Text Available In this study, new blended fuels were formed by adding 3–10 vol. % of acetone into a regular gasoline. According to the best of the author's knowledge, it is the first time that the influence of acetone blends has been studied in a gasoline-fueled engine. The blended fuels were tested for their energy efficiencies and pollutant emissions using SI (spark-ignition engine with single-cylinder and 4-stroke. Experimental results showed that the AC3 (3 vol.% acetone + 97 vol.% gasoline blended fuel has an advantage over the neat gasoline in exhaust gases temperature, in-cylinder pressure, brake power, torque and volumetric efficiency by about 0.8%, 2.3%, 1.3%, 0.45% and 0.9%, respectively. As the acetone content increases in the blends, as the engine performance improved where the best performance obtained in this study at the blended fuel of AC10. In particular, exhaust gases temperature, in-cylinder pressure, brake power, torque and volumetric efficiency increase by about 5%, 10.5%, 5.2%, 2.1% and 3.2%, respectively, compared to neat gasoline. In addition, the use of acetone with gasoline fuel reduces exhaust emissions averagely by about 43% for carbon monoxide, 32% for carbon dioxide and 33% for the unburnt hydrocarbons. The enhanced engine performance and pollutant emissions are attributed to the higher oxygen content, slight leaning effect, lower knock tendency and high flame speeds of acetone, compared to the neat gasoline. Finally the mechanism of acetone combustion in gasoline-fueled engines is proposed in this work; two main pathways for acetone combustion are highlighted; furthermore, the CO, CO2 and UHC (unburnt hydrocarbons mechanisms of formation and oxidation are acknowledged. Such acetone mechanism is employed for further understanding acetone combustion in spark-ignition engines.

  1. Mesure et modélisation multidimensionnelle des transferts thermiques gaz-paroi dans le cas des moteurs à allumage commandé Measurement and Multidimensional Modeling of Gas-Wall Heat Transfers in Spark-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Gilaber P.

    2006-11-01

    formulation k-epsilon de la turbulence a été adoptée. La sensibilité du modèle aux effets de densité et de turbulence a été testée par l'intermédiaire de variations de l'avance à l'allumage et du régime. La comparaison entre mesure et simulation a montré un bon accord, tant en termes de flux thermiques locaux et instantanés, qu'en termes de bilan global. The computational fluid dynamics codes, which help to predict the behaviour of combusting gas in reciprocating engines, need, as boundary conditions for the momentum and energy equations, to approximate wall frictions and heat transfer between gas and walls. The purpose of this work is to validate a heat transfer model for spark ignited engines. Two steps of research have been worked on to meet this objective: an experimental phase and a computational phase. In the experimental phase, measurements were made on a test-engine instrumented with fast-response surface heat flux gages. Each gage consisted of a steel cylinder, containing two thermocouples. To analyze the influence of fluid dynamics on heat transfer, a Laser Doppler Velocimeter was used, by means of a spacer placed between the engine head and cylinder. The spacer was equiped with two windows and two heat-flux gages permitting simultaneous measurements of the heat flux and of the fluid dynamics outside the boundary layer. Two other gages were present in the head of the engine and up to ten data inputs could be simultaneously recorded at each crank-angle, including two velocity components and the cylinder pressure. A parametric analysis was carried out revealing the following trends:- the global heat transfer rate for a thermodynamic cycle of the engine decreases as the speed of the engine is increased, but the peak value of the wall heat-flux increases because of the increase of the turbulence level. - the volumetric efficiency appeared to have little effect on the turbulence level, and its influence on the heat transfer is mainly due to the increase of

  2. Experimental cross-correlation nitrogen Q-branch CARS thermometry in a spark ignition engine

    Science.gov (United States)

    Lockett, R. D.; Ball, D.; Robertson, G. N.

    2013-07-01

    A purely experimental technique was employed to derive temperatures from nitrogen Q-branch Coherent Anti-Stokes Raman Scattering (CARS) spectra, obtained in a high pressure, high temperature environment (spark ignition Otto engine). This was in order to obviate any errors arising from deficiencies in the spectral scaling laws which are commonly used to represent nitrogen Q-branch CARS spectra at high pressure. The spectra obtained in the engine were compared with spectra obtained in a calibrated high pressure, high temperature cell, using direct cross-correlation in place of the minimisation of sums of squares of residuals. The technique is demonstrated through the measurement of air temperature as a function of crankshaft angle inside the cylinder of a motored single-cylinder Ricardo E6 research engine, followed by the measurement of fuel-air mixture temperatures obtained during the compression stroke in a knocking Ricardo E6 engine. A standard CARS programme (SANDIA's CARSFIT) was employed to calibrate the altered non-resonant background contribution to the CARS spectra that was caused by the alteration to the mole fraction of nitrogen in the unburned fuel-air mixture. The compression temperature profiles were extrapolated in order to predict the auto-ignition temperatures.

  3. Devices to improve the performance of a conventional two-stroke spark ignition engine

    Science.gov (United States)

    Poola, R. B.; Nagalingam, B.; Gopalakrishnan, K. V.

    1995-08-01

    This paper presents research efforts made in three different phases with the objective of improving the fuel economy of and reducing exhaust emissions from conventional, carbureted, two-stroke spark ignition (SI) engines, which are widely employed in two-wheel transportation in India. A review concerning the existing two-stroke engine technology for this application is included. In the first phase, a new scavenging system was developed and tested to reduce the loss of fresh charge through the exhaust port. In the second phase, the following measures were carried out to improve the combustion process: (1) using an in-cylinder catalyst, such as copper, chromium, and nickel, in the form of coating; (2) providing moderate thermal insulation in the combustion chamber, either by depositing thin ceramic material or by metal inserts; (3) developing a high-energy ignition system; and (4) employing high-octane fuel, such as methanol, ethanol, eucalyptus oil, and orange oil, as a blending agent with gasoline. Based on the effectiveness of the above measures, an optimized design was developed in the final phase to achieve improved performance. Test results indicate that with an optimized two-stroke SI engine, the maximum percentage improvement in brake thermal efficiency is about 31%, together with a reduction of 3400 ppm in hydrocarbons (HC) and 3% by volume of carbon monoxide (CO) emissions over the normal engine (at 3 kW, 3000 rpm). Higher cylinder peak pressures (3-5 bar), lower ignition delay (2-4 degrees CA), and shorter combustion duration (4-10 degrees CA) are obtained. The knock-limited power output is also enhanced by 12.7% at a high compression ratio (CR) of 9:1. The proposed modifications in the optimized design are simple, low-cost, and easy to adopt for both production and existing engines.

  4. Cycle-to-cycle fluctuation of combustion in a spark-ignition engine; Hibana tenka engine no nensho hendo

    Energy Technology Data Exchange (ETDEWEB)

    Hamamoto, Y.; Yoshiyama, S.; Tomita, E.; Hamagami, T. [Okayama University, Okayama (Japan); Otsubo, H. [Yammer Diesel Engine Co. Ltd. Tokyo (Japan)

    1997-10-01

    In a homogeneous charge spark-ignition engine, the duration of early stage of combustion is a dominant factor for determining the fluctuation of mean effective pressure. And the early stage of combustion varies with the equivalence ratio and turbulence characteristics of the mixture. In this study, the fluctuations of 1% combustion duration and indicated mean effective pressure Pmi were computed as the function of fluctuations both in the equivalence ratio {phi} of the mixture and in the turbulence characteristics of the cylinder charge. And effects of the spark timing {theta}ig and {phi} on the cycle-to-cycle fluctuation in Pmi were investigated. 16 refs., 6 figs.

  5. Schlieren-based temperature measurement inside the cylinder of an optical spark ignition and homogeneous charge compression ignition engine.

    Science.gov (United States)

    Aleiferis, Pavlos; Charalambides, Alexandros; Hardalupas, Yannis; Soulopoulos, Nikolaos; Taylor, A M K P; Urata, Yunichi

    2015-05-10

    Schlieren [Schlieren and Shadowgraphy Techniques (McGraw-Hill, 2001); Optics of Flames (Butterworths, 1963)] is a non-intrusive technique that can be used to detect density variations in a medium, and thus, under constant pressure and mixture concentration conditions, measure whole-field temperature distributions. The objective of the current work was to design a schlieren system to measure line-of-sight (LOS)-averaged temperature distribution with the final aim to determine the temperature distribution inside the cylinder of internal combustion (IC) engines. In a preliminary step, we assess theoretically the errors arising from the data reduction used to determine temperature from a schlieren measurement and find that the total error, random and systematic, is less than 3% for typical conditions encountered in the present experiments. A Z-type, curved-mirror schlieren system was used to measure the temperature distribution from a hot air jet in an open air environment in order to evaluate the method. Using the Abel transform, the radial distribution of the temperature was reconstructed from the LOS measurements. There was good agreement in the peak temperature between the reconstructed schlieren and thermocouple measurements. Experiments were then conducted in a four-stroke, single-cylinder, optical spark ignition engine with a four-valve, pentroof-type cylinder head to measure the temperature distribution of the reaction zone of an iso-octane-air mixture. The engine optical windows were designed to produce parallel rays and allow accurate application of the technique. The feasibility of the method to measure temperature distributions in IC engines was evaluated with simulations of the deflection angle combined with equilibrium chemistry calculations that estimated the temperature of the reaction zone at the position of maximum ray deflection as recorded in a schlieren image. Further simulations showed that the effects of exhaust gas recirculation and air

  6. Analysis of an Increase in the Efficiency of a Spark Ignition Engine Through the Application of an Automotive Thermoelectric Generator

    Science.gov (United States)

    Merkisz, Jerzy; Fuc, Pawel; Lijewski, Piotr; Ziolkowski, Andrzej; Galant, Marta; Siedlecki, Maciej

    2016-08-01

    We have analyzed the increase of the overall efficiency of a spark ignition engine through energy recovery following the application of an automotive thermoelectric generator (ATEG) of our own design. The design of the generator was developed following emission investigations during vehicle driving under city traffic conditions. The measurement points were defined by actual operation conditions (engine speed and load), subsequently reproduced on an engine dynamometer. Both the vehicle used in the on-road tests and the engine dynamometer were fit with the same, downsized spark ignition engine (with high effective power-to-displacement ratio). The thermodynamic parameters of the exhaust gases (temperature and exhaust gas mass flow) were measured on the engine testbed, along with the fuel consumption and electric current generated by the thermoelectric modules. On this basis, the power of the ATEG and its impact on overall engine efficiency were determined.

  7. Investigations on the effects of ethanol–methanol–gasoline blends in a spark-ignition engine: Performance and emissions analysis

    OpenAIRE

    Ashraf Elfasakhany

    2015-01-01

    This study discusses performance and exhaust emissions from spark-ignition engine fueled with ethanol–methanol–gasoline blends. The test results obtained with the use of low content rates of ethanol–methanol blends (3–10 vol.%) in gasoline were compared to ethanol–gasoline blends, methanol–gasoline blends and pure gasoline test results. Combustion and emission characteristics of ethanol, methanol and gasoline and their blends were evaluated. Results showed that when the vehicle was fueled wit...

  8. Investigations on the effects of ethanol–methanol–gasoline blends in a spark-ignition engine: Performance and emissions analysis

    OpenAIRE

    Ashraf Elfasakhany

    2015-01-01

    This study discusses performance and exhaust emissions from spark-ignition engine fueled with ethanol–methanol–gasoline blends. The test results obtained with the use of low content rates of ethanol–methanol blends (3–10 vol.%) in gasoline were compared to ethanol–gasoline blends, methanol–gasoline blends and pure gasoline test results. Combustion and emission characteristics of ethanol, methanol and gasoline and their blends were evaluated. Results showed that when the vehicle was fueled wit...

  9. Modelling Spark Integration in Science Classroom

    Directory of Open Access Journals (Sweden)

    Marie Paz E. Morales

    2014-02-01

    Full Text Available The study critically explored how a PASCO-designed technology (SPARK ScienceLearning System is meaningfully integrated into the teaching of selected topics in Earth and Environmental Science. It highlights on modelling the effectiveness of using the SPARK Learning System as a primary tool in learning science that leads to learning and achievement of the students. Data and observation gathered and correlation of the ability of the technology to develop high intrinsic motivation to student achievement were used to design framework on how to meaningfully integrate SPARK ScienceLearning System in teaching Earth and Environmental Science. Research instruments used in this study were adopted from standardized questionnaires available from literature. Achievement test and evaluation form were developed and validated for the purpose of deducing data needed for the study. Interviews were done to delve into the deeper thoughts and emotions of the respondents. Data from the interviews served to validate all numerical data culled from this study. Cross-case analysis of the data was done to reveal some recurring themes, problems and benefits derived by the students in using the SPARK Science Learning System to further establish its effectiveness in the curriculum as a forerunner to the shift towards the 21st Century Learning.

  10. Enhanced Model for Fast Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Mason, Rodney J. [Research Applications Corporation, Los Alamos, NM (United States)

    2010-10-12

    Laser Fusion is a prime candidate for alternate energy production, capable of serving a major portion of the nation's energy needs, once fusion fuel can be readily ignited. Fast Ignition may well speed achievement of this goal, by reducing net demands on laser pulse energy and timing precision. However, Fast Ignition has presented a major challenge to modeling. This project has enhanced the computer code ePLAS for the simulation of the many specialized phenomena, which arise with Fast Ignition. The improved code has helped researchers to understand better the consequences of laser absorption, energy transport, and laser target hydrodynamics. ePLAS uses efficient implicit methods to acquire solutions for the electromagnetic fields that govern the accelerations of electrons and ions in targets. In many cases, the code implements fluid modeling for these components. These combined features, "implicitness and fluid modeling," can greatly facilitate calculations, permitting the rapid scoping and evaluation of experiments. ePLAS can be used on PCs, Macs and Linux machines, providing researchers and students with rapid results. This project has improved the treatment of electromagnetics, hydrodynamics, and atomic physics in the code. It has simplified output graphics, and provided new input that avoids the need for source code access by users. The improved code can now aid university, business and national laboratory users in pursuit of an early path to success with Fast Ignition.

  11. Studies on exhaust emissions of catalytic coated spark ignition engine with adulterated gasoline.

    Science.gov (United States)

    Muralikrishna, M V S; Kishor, K; Venkata Ramana Reddy, Ch

    2006-04-01

    Adulteration of automotive fuels, especially, gasoline with cheaper fuels is widespread throughout south Asia. Some adulterants decrease the performance and life of the engine and increase the emission of harmful pollutants causing environmental and health problems. The present investigation is carried out to study the exhaust emissions from a single cylinder spark ignition (SI) engine with kerosene blended gasoline with different versions of the engine, such as conventional engine and catalytic coated engine with different proportions of the kerosene ranging from 0% to 40% by volume in steps of 10% in the kerosene-gasoline blend. The catalytic coated engine used in the study has copper coating of thickness 400 microns on piston and inner surface of the cylinder head. The pollutants in the exhaust, carbon monoxide (CO) and unburnt hydrocarbons (UBHC) are measured with Netel Chromatograph CO and HC analyzer at peak load operation of the engine. The engine is provided with catalytic converter with sponge iron as a catalyst to control the pollutants from the exhaust of the engine. An air injection is also provided to the catalytic converter to further reduce the pollutants. The pollutants found to increase drastically with adulterated gasoline. Copper-coated engine with catalytic converter significantly reduced pollutants, when compared to conventional engine.

  12. Structure and disposition of particles from a spark-ignition engine

    Science.gov (United States)

    Steiner, D.; Burtscher, H.; Gross, H.

    Particles generated in the exhaust of a spark-ignition engine operated with leaded and unleaded fuel exhibit significant changes of size, structure and surface chemical composition on changing the temperature T of the carrier gas. Total mass, mass of black carbon (BC), diameter and the photoelectric yield of the particles have been measured in situ as a function of temperature. Concomitantly the particles have also been deposited on a substrate and imaged by transmission electron microscopy. Diameter and total mass of the particles decrease significantly with increasing T, whereas the BC mass remains nearly unaffected. From diameter and photoyield vs T curve a shell structure of the particles emerges, where the outermost shell is made up of volatile organic components followed by a layer of polycyclic aromatic hydrocarbons (PAHs) with less volatility on a core of BC and, depending on the type of fuel, also lead. Transmission electron micrographs indicate that lead and carbonaceous fractions segregate at T = 275°C. For T > 275°C and almost perfect crystalline order of lead appears.

  13. Biofuel and Hydrogen Influence for Operation Parameters of Spark Ignition Engine

    Directory of Open Access Journals (Sweden)

    Martynas Damaševičius

    2016-12-01

    Full Text Available Paper presents research of efficient and ecological parameters of gasoline engine working with biobuthanol (10% and 20% by volume and addi-tionaly supplying oxygen and hydrogen (HHO gas mixture (3.6 l/min, which was obtained from from water by electrolysis. Biobuthanol addition decreases rate of heat release, the combustion temperature and pressure are lower, which has an influence on lower nitrous oxide (NOx emission in exhaust gases. However, biobuthanol increases carbon monoxide (CO concentration. Biobuthanol fuel has a simplier molecular structure, therefore the concentration of HC in the exhaust gas is decreasing. Due to lower heating value of biobuthanol fuel and slower combustion process, the engine efficiency decreases and specific fuel consumptions increase. The change of engine energetical indicators due to biobuthanol, can be compensated with advanced ignition angle. Using experimental investigation, it was determined, that negative biobuthanol influence for the combustion process and engine efficient inicators can be compensated also by additional supplied HHO gas, in which the hydrogen element iprove fuel mixture com-bustion. Fuel combustion process analysis was carried out using AVL BOOST software. Experimental research and combustion process numerical simulation showed that using balanced biobuthanol and hydrogen addition, optimal efficient and ecological parameters could be achieved, when engine is working for petrol fuel typical optimal spark timing.

  14. Determination of knock characteristics in spark ignition engines: an approach based on ensemble empirical mode decomposition

    Science.gov (United States)

    Li, Ning; Yang, Jianguo; Zhou, Rui; Liang, Caiping

    2016-04-01

    Knock is one of the major constraints to improve the performance and thermal efficiency of spark ignition (SI) engines. It can also result in severe permanent engine damage under certain operating conditions. Based on the ensemble empirical mode decomposition (EEMD), this paper proposes a new approach to determine the knock characteristics in SI engines. By adding a uniformly distributed and finite white Gaussian noise, the EEMD can preserve signal continuity in different scales and therefore alleviates the mode-mixing problem occurring in the classic empirical mode decomposition (EMD). The feasibilities of applying the EEMD to detect the knock signatures of a test SI engine via the pressure signal measured from combustion chamber and the vibration signal measured from cylinder head are investigated. Experimental results show that the EEMD-based method is able to detect the knock signatures from both the pressure signal and vibration signal, even in initial stage of knock. Finally, by comparing the application results with those obtained by short-time Fourier transform (STFT), Wigner-Ville distribution (WVD) and discrete wavelet transform (DWT), the superiority of the EEMD method in determining knock characteristics is demonstrated.

  15. EXPERIMENTAL INVESTIGATION OF COLD START EMISSIONS USING ELECTRICALLY HEATED CATALYSTS IN A SPARK IGNITION ENGINE

    Directory of Open Access Journals (Sweden)

    K. Bhaskar

    2010-12-01

    Full Text Available The population of spark-ignition vehicles in urban areas is very high and is increasing rapidly due to their convenience for short distance transportation. These vehicles are major sources of urban air pollution compared to vehicles with diesel engines. Catalytic converters are used to control their emissions but they attain their maximum conversion rates of about 80%¬–90% under optimum operating conditions and are not effective during cold start conditions. The objective of the present work is to demonstrate that an electrically heated catalyst (EHC in combination with a traditional converter can achieve the Low and Ultra Low Emission Vehicle (LEV, ULEV standards. Experiments were conducted to investigate the impact of various metal oxides in EHC and design parameters to reduce cold-start emissions of a multi-cylinder SI engine. It is observed that EHC reduces cold-start hydrocarbon and carbon monoxide emissions when used with an existing catalytic converter. The maximum CO and HC reductions were achieved with copper oxide as the catalyst in EHC with air injection of 80 lpm for 40 sec after cold start of the engine.

  16. FUEL EFFECTS ON COMBUSTION WITH EGR DILUTION IN SPARK IGNITED ENGINES

    Energy Technology Data Exchange (ETDEWEB)

    Szybist, James P [ORNL

    2016-01-01

    The use of EGR as a diluent allows operation with an overall stoichiometric charge composition, and the addition of cooled EGR results in well-understood thermodynamic benefits for improved fuel consumption. This study investigates the effect of fuel on the combustion and emission response of EGR dilution in spark ignited engines. A 2.0 L GM Ecotec LNF engine equipped with the production side-mounted direct injection (DI) fueling system is used in this study. Ethanol, isooctane and certified gasoline are investigated with EGR from 0% to the EGR dilution tolerance. Constant BMEP at 2000 rpm was operated with varying CA50 from 8 CAD to 16 CAD aTDCf. The results show that ethanol gives the largest EGR tolerance at a given combustion phasing, engine load and speed. The improved EGR dilution tolerance with ethanol is attributed to a faster flame speed, which manifests itself as shorter combustion duration. Data shows that the combustion stability limit occurs at a critical combustion duration that is fuel independent. Due to different flame speeds, this critical combustion duration occurs at different EGR levels for the different fuels.

  17. ANALYSIS OF HYDROCARBON TREATING SYSTEM TO THE EMISSION OFF SPARK-IGNITION FOUR-STROKE ENGINE

    Directory of Open Access Journals (Sweden)

    Binyamin Binyamin

    2016-08-01

    Full Text Available The reduction of carbon monoxide (CO, unburnthydrocarbon (UHC emission and fuel consumption on spark-ignition four-stroke engine is continuously attempted. The purposes from this research were to determine the effect of Hydrocarbon Treating System (HTS  on levels of CO, UHC and fuel consumption. This is an experimental research. Its is conducted by comparing the exhaust pollutant concentration such as carbon monoxide, unburnt hydrocarbon and also fuel consumption between standard engine setting and Hydrocarbon Treating System applied. The research variable are HTS flow rate from Q1 = 0 cc/s (without HTS, Q2 = 1,5 cc/s, Q3 = 2 cc/s, Q4 = 2,5 cc/s, and Q5 = 33 cc/s. The research will be done in three conditions which are low, medium and high rotation. The result showed that Hydrocarbon Threating System decrease fuel consumption up to 19,43% with flow rate Q5 = 3 cc/s, but on the other hand it increase CO emission up to 80.84% with flow rate Q5 = 3 cc/s and UHC emission level up to 124.75% with flow rate Q5 = 3 cc/s from engine standart condition.

  18. CONVERSION OF DIESEL ENGINE INTO SPARK IGNITION ENGINE TO WORK WITH CNG AND LPG FUELS FOR MEETING NEW EMISSION NORMS

    Directory of Open Access Journals (Sweden)

    Syed Kaleemuddin

    2010-01-01

    Full Text Available Fluctuating fuel prices and associated pollution problems of largely exploited petroleum liquid fuel has stimulated the research on abundantly available gaseous fuels to keep the mobility industry intact. In the present work an air cooled diesel engine was modified suitably into a spark ignition engine incorporating electronic ignition and variable speed dependant spark timing to accommodate both LPG and CNG as fuels. Engine was optimized for stoichiometric operation on engine dynamometer. Materials of a few intricate engine components were replaced to suit LPG and CNG application. Ignition timing was mapped to work with gaseous fuels for different speeds. Compensation was done for recovering volumetric efficiency when operated with CNG by introducing more volume of air through resonator. Ignition timing was observed to be the pertinent parameter in achieving good performance with gaseous fuels under consideration. Performance and emission tests were carried out on engine dynamometer and chassis dynamometer. Under wide open throttle and at rated speed condition, it was observed that the peak pressure with LPG was lying between diesel fuel and CNG fuel operation due to slow burning nature of gaseous fuels. As compression ratio was maintained same for LPG and CNG fuel operation, low CO emissions were observed with LPG where as HC + NOx emissions were lower with CNG fuel operation. Chassis dynamometer based emission tests yielded lower CO2 levels with CNG operation.

  19. Robust Control of the Air to Fuel Ratio in Spark Ignition Engines with Delayed Measurements from a UEGO Sensor

    Directory of Open Access Journals (Sweden)

    Javier Espinoza-Jurado

    2015-01-01

    Full Text Available A precise control of the normalized air to fuel ratio in spark ignition engines is an essential task. To achieve this goal, in this work we take into consideration the time delay measurement presented by the universal exhaust gas oxygen sensor along with uncertainties in the volumetric efficiency. For that purpose, observers are designed by means of a super-twisting sliding mode estimation scheme. Also two control schemes based on a general nonlinear model and a similar nonlinear affine representation for the dynamics of the normalized air to fuel ratio were designed in this work by using the super-twisting sliding mode methodology. Such dynamics depends on the control input, that is, the injected fuel mass flow, its time derivative, and its reciprocal. The two latter terms are estimated by means of a robust sliding mode differentiator. The observers and controllers are designed based on an isothermal mean value engine model. Numeric and hardware in the loop simulations were carried out with such model, where parameters were taken from a real engine. The obtained results show a good output tracking and rejection of disturbances when the engine is closed loop with proposed control methods.

  20. MOTIONS STUDY OF A SINGLE CYLINDER HIGH SPEED SPARK IGNITION LINIER ENGINE WITH SPRING SYSTEM AS RETURN CYCLE

    Directory of Open Access Journals (Sweden)

    A. Z.M. Fathallah

    2014-01-01

    Full Text Available A single cylinder two stroke spark ignition conventional engine have been modified to linier engine with spring mechanism. Before develop the design of linear engine is necessary to analysis of motion. Although principle of combustion process in combustion chamber is the same in fact the oscillation movement is different. Simulation technique has been adopted to study both linear and conventional engine. 3D engines model have been simulate of the motion. Due to simulate both engines, three different tools have been used. Solid works has been used to design, assembly and motion analysis of engine models. However, pressure dynamics have been simulating by GT-Power. Spread sheet has been used to optimize geometry of spring. Spring force and friction force are including components of dynamic and gas dynamic models. Three results have been conducted such as comparison in basic motion (displacement, velocity and acceleration between conventional and linear engine, effect spring design on motion of piston movement and effect friction of piston ring and journal bearing on the motion characteristics of linear engine. The simulation shows clear different motion characteristics between conventional and linear engine. The effect of spring design on motion characteristics is very strong. The friction between ring piston with cylinder liner and journal bearing with rod influenced of piston movement. However, it need modified the design of spring mechanism.

  1. Nonlinear torque and air-to-fuel ratio control of spark ignition engines using neuro-sliding mode techniques.

    Science.gov (United States)

    Huang, Ting; Javaherian, Hossein; Liu, Derong

    2011-06-01

    This paper presents a new approach for the calibration and control of spark ignition engines using a combination of neural networks and sliding mode control technique. Two parallel neural networks are utilized to realize a neuro-sliding mode control (NSLMC) for self-learning control of automotive engines. The equivalent control and the corrective control terms are the outputs of the neural networks. Instead of using error backpropagation algorithm, the network weights of equivalent control are updated using the Levenberg-Marquardt algorithm. Moreover, a new approach is utilized to update the gain of corrective control. Both modifications of the NSLMC are aimed at improving the transient performance and speed of convergence. Using the data from a test vehicle with a V8 engine, we built neural network models for the engine torque (TRQ) and the air-to-fuel ratio (AFR) dynamics and developed NSLMC controllers to achieve tracking control. The goal of TRQ control and AFR control is to track the commanded values under various operating conditions. From simulation studies, the feasibility and efficiency of the approach are illustrated. For both control problems, excellent tracking performance has been achieved.

  2. Prediction of cold start hydrocarbon emissions of air cooled two wheeler spark ignition engines by simple fuzzy logic simulation

    Directory of Open Access Journals (Sweden)

    Samuel Raja Ayyanan

    2014-01-01

    Full Text Available The cold start hydrocarbon emission from the increasing population of two wheelers in countries like India is one of the research issues to be addressed. This work describes the prediction of cold start hydrocarbon emissions from air cooled spark ignition engines through fuzzy logic technique. Hydrocarbon emissions were experimentally measured from test engines of different cubic capacity, at different lubricating oil temperature and at different idling speeds with and without secondary air supply in exhaust. The experimental data were used as input for modeling average hydrocarbon emissions for 180 seconds counted from cold start and warm start of gasoline bike engines. In fuzzy logic simulation, member functions were assigned for input variables (cubic capacity and idling rpm and output variables (average hydrocarbon emission for first 180 seconds at cold start and warm start. The knowledge based rules were adopted from the analyzed experimental data and separate simulations were carried out for predicting hydrocarbon emissions from engines equipped with and without secondary air supply. The simulation yielded the average hydrocarbon emissions of air cooled gasoline engine for a set of given input data with accuracy over 90%.

  3. Conversion of a commercial spark ignition engine to run on hydrogen: Performance comparison using hydrogen and gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Sopena, C.; Dieguez, P.M.; Sainz, D.; Urroz, J.C.; Gandia, L.M. [Escuela Tecnica Superior de Ingenieros Industriales y de Telecomunicacion, Universidad Publica de Navarra, Campus de Arrosadia, E-31006 Pamplona (Spain); Guelbenzu, E. [Acciona Biocombustibles S.A., Avenida Ciudad de la Innovacion n 5, E-31621 Sarriguren, Navarra (Spain)

    2010-02-15

    The modifications performed to convert the spark ignition gasoline-fueled internal combustion engine of a Volkswagen Polo 1.4 to run with hydrogen are described. The car is representative of small vehicles widely used for both city and interurban traffic. Main changes included the inlet manifold, gas injectors, oil radiator and the electronic management unit. Injection and ignition advance timing maps were developed for lean mixtures with values of the air to hydrogen equivalence ratio ({lambda}) between 1.6 and 3. The established engine control parameters allowed the safe operation of the hydrogen-fueled engine (H{sub 2}ICE) free of knock, backfire and pre-ignition as well with reasonably low NO{sub x} emissions. The H{sub 2}ICE reached best brake torque of 63 Nm at 3800 rpm and maximum brake power of 32 kW at 5000 rpm. In general, the brake thermal efficiency of the H{sub 2}ICE is greater than that of gasoline-fueled engine except for the H{sub 2}ICE working at very lean conditions ({lambda} = 2.5) and high speeds (above 4000 rpm). A significant effect of the spark advance on the NO{sub x} emissions has been found, specially for relatively rich mixtures ({lambda} < 2). Small changes of spark advance with respect to the optimum value for maximum brake torque give rise to an increase of pollutant emissions. It has been estimated that the hydrogen-fueled Volkswagen Polo could reach a maximum speed of 140 km/h with the adapted engine. Moreover, there is enough reserve of power for the vehicle moving on typical urban routes and routes with slopes up to 10%. (author)

  4. Ignition of dust clouds by sparks and heated surfaces; Inflammation des nuages de poussieres par des etincelles et des surfaces chauffees

    Energy Technology Data Exchange (ETDEWEB)

    Proust, C.; Boudalaa, M. [Institut National de l' Environnement Industriel et des Risques, 60 - Verneuil en Halatte (INERIS) (France)

    2001-07-01

    The three types of ignition sources described in this article are the sources of mechanical origin, the heated surfaces and the sparks of electrostatic origin. These 3 categories should be at the origin of 75% of the referenced dust explosions. The approach retained is mainly experimental. Hot spots are produced by the impact of a laser beam (Nd-YAG) on a target located inside the cloud. For relatively long delays of ignition (1 to 2 mn), the characteristic ignition parameter is the thermal power supplied by the target to the mixture, at least when the hot-spot size is small enough (less than 2 or 3 mm). Above this size, the ignition parameter would rather be a critical temperature of the hot spot which can be linked to the 'standard' ignition temperature of the cloud. For electrostatic sparks, measurements of current-voltage characteristics have been performed with some measurements of dimensions. Most possible types have been examined, like the discharges between conductive materials (A), between a conductive material and an insulating material (B), and between a conductive material and an insulating material lined with a conductor connected to the ground (C). It appears that the most powerful sparks (several joules) encountered in the industrial environment are those of type A and C. Measurements have shown that the efficiency of the conversion of the energy stored on the surface of the material into electrical energy inside the spark is very high. Finally, a first approach of the examination of the ignition risk has been tempted with a hot spot created during a lapse of time compatible with a mechanical impact. This leads to an ignition criterion in the form of energy. This energy remains at least two scales of size greater than the minimum spark ignition energy. This difference should come from the absorption of heat by solid materials. (J.S.)

  5. Behaviour analysis of the fuel injected in the intake manifold of port-injected spark ignition engines: modeling and experimental validation; Analyse du comportement du carburant injecte dans les conduits d`admission des moteurs a allumage commande a injection multipoint: modelisation et validation experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Sches, C.

    1999-01-27

    In order to limit pollutant emissions resulting from transient engine operation, the mastering of mixture formation is essential. In this context, an interactive work was undertaken between a modeling job and an experimental study, to get better understanding of the mechanisms of fuel dynamic behavior in the intake manifold of port-injected spark-ignition engines. The experimental study, elaborated thanks to experimental designs, showed out two essential factors: injection timing and coolant liquid temperature, which act on the fuel dynamic behavior through a second order filter. Then, a phenomenological modeling was established and validated, to analyze the various phenomena influencing mixture formation and to calculate the air/fuel ratio evolutions during transient operation. This program uses the results of a 3D model describing the fuel spray transportation, evaporation and impact on the port walls. The calculation does not need any boundary conditions and the running times are vary satisfactory. We showed that a correct description of the liquid fuel film was necessary to get good prediction of the mixture fuel/air ratio. The spray modeling, which is necessary, can however be kept simple. Future work may develop either in the engine control filed (injection strategies development, optimization of the injection system configuration, ...), or in the theoretical field (better modeling of fuel film displacement or of secondary atomization of the fuel on the intake valve). (author) 79 refs.

  6. Ignition of an automobile engine by high-peak power Nd:YAG/Cr⁴⁺:YAG laser-spark devices.

    Science.gov (United States)

    Pavel, Nicolaie; Dascalu, Traian; Salamu, Gabriela; Dinca, Mihai; Boicea, Niculae; Birtas, Adrian

    2015-12-28

    Laser sparks that were built with high-peak power passively Q-switched Nd:YAG/Cr(4+):YAG lasers have been used to operate a Renault automobile engine. The design of such a laser spark igniter is discussed. The Nd:YAG/Cr(4+):YAG laser delivered pulses with energy of 4 mJ and 0.8-ns duration, corresponding to pulse peak power of 5 MW. The coefficients of variability of maximum pressure (COV(Pmax)) and of indicated mean effective pressure (COV(IMEP)) and specific emissions like hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO(x)) and carbon dioxide (CO2) were measured at various engine speeds and high loads. Improved engine stability in terms of COV(Pmax) and COV(Pmax) and decreased emissions of CO and HC were obtained for the engine that was run by laser sparks in comparison with classical ignition by electrical spark plugs.

  7. Incorporating in-cylinder pressure data to predict NO{sub x} emissions from spark-ignition engines fueled with landfill gas/hydrogen mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Kornbluth, Kurt; McCaffrey, Zach; Erickson, Paul A. [Department of Mechanical and Aerospace Engineering, University of California, One Shields Avenue, Davis, CA 95616 (United States)

    2009-11-15

    A 0.745 L 2-cylinder spark-ignition engine was operated with compressed natural gas and with simulated landfill gas (60% CH{sub 4} and 40% CO{sub 2} by volume) containing hydrogen concentrations of 0, 30%, 40%, and 50% (by volume of the CH{sub 4} in the fuel) at constant rpm. This empirical data was compared with predictions from three existing semi-empirical engine models, using a first-law-based finite heat release model to correlate measured in-cylinder pressure data and burn rate for each fuel mixture. Of the three models only a two zone model incorporating thermal and prompt NO{sub x} came within 25% of predicting the measured NO{sub x} emissions. (author)

  8. Wavelet analysis of cyclic variability in a spark ignition engine powered by gasoline-hydrogen fuel blends

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Asok K. [Richard G. Lugar Centre for Renewable Energy, and Department of Mathematical Sciences, Indiana University, (United States)], email: asen@iupui.edu; Akif Ceviz, M.; Volkan Oner, I. [Department of Mechanical Engineering, University of Ataturk (Turkey)], email: aceviz@atauni.edu.tr

    2011-07-01

    The cycle-to-cycle variations (CCV) of the indicated mean effective pressure (IMEP) in a spark ignition engine fuelled by gasoline and gasoline-hydrogen blends is investigated. CCVs are estimated by using the coefficient of variation (COV) and the overall spectral power given by the global wavelet spectrum (GWS). It was found that the addition of hydrogen reduces the CCV of the IMEP. Analysis of the wavelet can also identify the dominant modes of variability and delineate the engine cycles over which these modes can persist. Air-fuel ratio was varied from 1.0 to 1.3, and hydrogen was added up to 7.74% by volume. The engine was operated at 2000 rpm. Results demonstrate that subject to air-fuel ratio and % of hydrogen added, IMEP time series can exhibit multiscale dynamics consisting of persistent oscillations and intermittent fluctuations. These results can help develop effective control strategies to reduce cyclic variability in a spark ignition engine fuelled by gasoline-hydrogen mixtures.

  9. Selection Criteria and Screening of Potential Biomass-Derived Streams as Fuel Blendstocks for Advanced Spark-Ignition Engines

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, Robert L.; Fioroni, Gina; Fouts, Lisa; Christensen, Earl; Yanowitz, Janet; Polikarpov, Evgueni; Albrecht, Karl; Gaspar, Daniel J.; Gladden, John; George, Anthe

    2017-03-14

    We describe a study to identify potential biofuels that enable advanced spark ignition (SI) engine efficiency strategies to be pursued more aggressively. A list of potential biomass-derived blendstocks was developed. An online database of properties and characteristics of these bioblendstocks was created and populated. Fuel properties were determined by measurement, model prediction, or literature review. Screening criteria were developed to determine if a bioblendstock met the requirements for advanced SI engines. Criteria included melting point (or cloud point) < -10 degrees C and boiling point (or T90) <165 degrees C. Compounds insoluble or poorly soluble in hydrocarbon were eliminated from consideration, as were those known to cause corrosion (carboxylic acids or high acid number mixtures) and those with hazard classification as known or suspected carcinogens or reproductive toxins. Compounds predicted to be less anaerobically biodegradable than methyl-tert-butyl ether with water solubility greater than 10,000 mg/L were also eliminated. A minimum Research octane number (RON) of 98 was applied. These criteria produced a list of 40 bioblendstocks with promising properties. Additional property data, including Motor octane number (MON), heat of vaporization, and lower heating value, were acquired for these bioblendstocks. A subset of the bioblendstocks representing all functional groups were blended into gasoline or a gasoline surrogate to measure their effect on vapor pressure, distillation curve, oxidation stability, RON, and MON. For blending into a conventional or reformulated blendstock for E10 blending, ethanol, 2-butanol, isobutanol, and diisobutylene have the most desirable properties for blending of a high-octane advanced SI engine fuel.

  10. Effects of Fuel Composition on EGR Dilution Tolerance in Spark Ignited Engines

    Energy Technology Data Exchange (ETDEWEB)

    Szybist, James P [ORNL

    2016-01-01

    Fuel-specific differences in exhaust gas recirculation (EGR) dilution tolerance are studied in a modern, direct-injection single-cylinder research engine. A total of 6 model fuel blends are examined at a constant research octane number (RON) of 95 using n-heptane, iso-octane, toluene, and ethanol. Laminar flame speeds for these mixtures, which were calculated two different methods (an energy fraction mixing rule and a detailed kinetic simulation), spanned a range of about 6 cm/s. A constant fueling nominal load of 350 kPa IMEPg at 2000 rpm was operated with varying CA50 from 8-20 CAD aTDCf, and with EGR increasing until a COV of IMEP of 5% is reached. The results illustrate that flame speed affects EGR dilution tolerance; fuels with increased flame speeds increase EGR tolerance. Specifically, flame speed correlates most closely to the initial flame kernel growth, measured as the time of ignition to 5% mass fraction burned. The effect of the latent heat of vaporization on the flame speed is taken into account for the ethanol-containing fuels. At a 30 vol% blend level, the increased enthalpy of vaporization of ethanol compared to conventional hydrocarbons can decrease the temperature at the time of ignition by a maximum of 15 C, which can account for up to a 3.5 cm/s decrease in flame speed. The ethanol-containing fuels, however, still exhibit a flame speed advantage, and a dilution tolerance advantage over the slower flame-speed fuels. The fuel-specific differences in dilution tolerance are significant at the condition examined, allowing for a 50% relative increase in EGR (4% absolute difference in EGR) at a constant COV of IMEP of 3%.

  11. Modelling piloted ignition of wood and plastics

    NARCIS (Netherlands)

    Blijderveen, M. van; Bramer, E.A.; Brem, G.

    2012-01-01

    To gain insight in the startup of an incinerator, this article deals with piloted ignition. A newly developed model is described to predict the piloted ignition times of wood, PMMA and PVC. The model is based on the lower flammability limit and the adiabatic flame temperature at this limit. The inco

  12. Analysis of Modifications on a Spark Ignition Engine for Operation with Natural Gas

    Directory of Open Access Journals (Sweden)

    Ramasamy D.

    2016-01-01

    Full Text Available Transportation is one of the key contributors to petroleum usage and emissions to the atmosphere. According to researchers, there are many ways to use transport by using renewable energy sources. Of these solutions, the immediate solution which requires less modification to current engine technology is by using gaseous fuels. Natural gas is the fuel of choice for minor modification to current engines. As it can be derived from anaerobic digestion process, the potential as a renewable energy source is tremendous, especially for an agricultural country such a Malaysia. The aim in the future will be operating an engine with natural gas only with pipelines straight to houses for easy filling. The fuel is light and can be easily carried in vehicles when in compressed form. As such, Compressed Natural Gas (CNG is currently used in bi-fuel engines, but is mostly not optimized in term of their performance. The focus of the paper is to optimize a model of natural gas engine by one dimensional flow modeling for operation with natural gas. The model is analyzed for performance and emission characteristics produced by a gasoline engine and later compared with natural gas. The average performance drop is about 15% from its gasoline counterpart. The 4% benchmark indicates that the modification to ignition timing and compression ratio does improve engine performance using natural gas as fuel.

  13. On the study of threshold intensity dependence on the gain and loss processes in laser induced spark ignition of molecular hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Omar, M. M., E-mail: magdymomar@gmail.com; Aboulfotouh, A. M. [Department of physics, Faculty of Science, Cairo University, Giza (Egypt); Gamal, Y. E. E. [National Institute of Laser Enhanced Sciences, Cairo University, Giza (Egypt)

    2015-03-30

    In the present work, a numerical analysis is performed to investigate the comparative contribution of the mechanisms responsible for electron gain and losses in laser spark ignition and plasma formation of H{sub 2}. The analysis considered H{sub 2} over pressure range 150 -3000 torr irradiated by a Nd:YAG laser radiation at wavelengths 1064 and 532 nm with pulse length 5.5 ns. The study based on a modified electron cascade model by one of the authors which solves numerically the time dependent Boltzmann equation as well as a set of rate equations that describe the rate of change of the excited states population. The model includes most of the physical processes that might take place during the interaction. Computations of The threshold intensity are performed for the combined and separate contribution of each of the gain and loss processes. Reasonable agreement with the measured values over the tested pressure range is obtained only for the case of the combined contribution. Basing on the calculation of the electron energy distribution function, the determined relations of the time evolution of the electrons density for selected values of the tested gas pressure region revealed that photo-ionization of the excited states could determine the time of electron generation and hence spark ignition. Collisional ionization contributes to this phenomenon only at the high pressure regime. Loss processes due to electron diffusion, vibrational excitation are found to have significant effect over examined pressure values for the two applied laser wavelengths.

  14. Spark Ignition of Combustible Vapor in a Plastic Bottle as a Demonstration of Rocket Propulsion

    Science.gov (United States)

    Mattox, J. R.

    2017-01-01

    I report an innovation that provides a compelling demonstration of rocket propulsion, appropriate for students of physics and other physical sciences. An electrical spark is initiated from a distance to cause the deflagration of a combustible vapor mixed with air in a lightweight plastic bottle that is consequently propelled as a rocket by the…

  15. Extension of the lean limit through hydrogen enrichment of a LFG-fueled spark-ignition engine and emissions reduction

    Energy Technology Data Exchange (ETDEWEB)

    Kornbluth, Kurt; Greenwood, Jason; McCaffrey, Zach; Vernon, David; Erickson, Paul [Mechanical and Aerospace Engineering Department, UC Davis, CA 95616 (United States)

    2010-02-15

    In this experimental investigation the affect of hydrogen addition to a landfill gas-fueled naturally-aspirated spark-ignition engine was explored. Hydrogen concentrations of 0%, 30%, 40%, and 50% by volume were added to simulated landfill gas (60% CH{sub 4} and 40% CO{sub 2}). Efficiency, coefficient of variance of indicated mean effective pressure, and CO emissions were measured from near stoichiometric mixtures up to the lean operating limit. Engine-out NOx emissions were compared to predicted future best available control technology targets for NOx emissions in landfill gas-to-energy projects. From this study, it was determined that with 40% hydrogen by volume untreated exhaust NOx emissions can meet the 0.22 g/kWh NOx target while retaining 95% of baseline power and low CO emissions. (author)

  16. A High-Speed Motion-Picture Study of Normal Combustion, Knock and Preignition in a Spark-Ignition Engines

    Science.gov (United States)

    Rothrock, A M; Spencer, R C; Miller, Cearcy D

    1941-01-01

    Combustion in a spark-ignition engine was investigated by means of the NACA high-speed motion-picture cameras. This camera is operated at a speed of 40,000 photographs a second and therefore makes possible the study of changes that take place in the intervals as short as 0.000025 second. When the motion pictures are projected at the normal speed of 16 frames a second, any rate of movement shown is slowed down 2500 times. Photographs are presented of normal combustion, of combustion from preignitions, and of knock both with and without preignition. The photographs of combustion show that knock may be preceded by a period of exothermic reaction in the end zone that persists for a time interval of as much as 0.0006 second. The knock takes place in 0.00005 second or less.

  17. Composite adaptive and input observer-based approaches to the cylinder flow estimation in spark ignition automotive engines

    Energy Technology Data Exchange (ETDEWEB)

    Stotsky, A.; Eriksson, S. [Volvo Car Corporation, Gothenburg (Sweden). Engine Design and Development Dept.; Kolmanovsky, I. [Ford Motor Co., Dearborn, MI (United States)

    2004-07-01

    The performance of air charge estimation algorithms in spark ignition automotive engines can be enhanced using advanced estimation techniques available in the controls literature. This paper illustrates two approaches of this kind that can improve the cylinder flow estimation for gasoline engines without external exhaust gas recirculation (EGR). The first approach is based on an input observer, while the second approach relies on an adaptive estimator. Assuming that the cylinder flow is nominally estimated via a speed-density calculation, and that the uncertainty is additive to the volumetric efficiency, the straightforward application of an input observer provides an easy to implement algorithm that corrects the nominal air flow estimate. The experimental results that we report in the paper point to a sufficiently good transient behaviour of the estimator. The signal quality may deteriorate, however, for extremely fast transients. This motivates the development of an adaptive estimator that relies mostly on the feedforward speed-density calculation during transients, while during engine operation close to steady-state conditions, it relies mostly on the adaptation. In our derivation of the adaptive estimator, the uncertainty is modelled as an unknown parameter multiplying the intake manifold temperature. We use the tracking error between the measured and modelled intake manifold pressure together with an appropriately defined prediction error estimate to develop an adaptation algorithm with improved identifiability and convergence rate. A robustness enhancement, via a {sigma}-modification with the {sigma}-factor depending on the prediction error estimate, ensures that in transients the parameter estimate converges to a predetermined a priori value. In close to steady-state conditions, the {sigma}-modification is rendered inactive and the evolution of the parameter estimate is determined by both tracking error and prediction error estimate. Further enhancements are

  18. The Effect of Compression Ratio, Fuel Octane Rating, and Ethanol Content on Spark-Ignition Engine Efficiency.

    Science.gov (United States)

    Leone, Thomas G; Anderson, James E; Davis, Richard S; Iqbal, Asim; Reese, Ronald A; Shelby, Michael H; Studzinski, William M

    2015-09-15

    Light-duty vehicles (LDVs) in the United States and elsewhere are required to meet increasingly challenging regulations on fuel economy and greenhouse gas (GHG) emissions as well as criteria pollutant emissions. New vehicle trends to improve efficiency include higher compression ratio, downsizing, turbocharging, downspeeding, and hybridization, each involving greater operation of spark-ignited (SI) engines under higher-load, knock-limited conditions. Higher octane ratings for regular-grade gasoline (with greater knock resistance) are an enabler for these technologies. This literature review discusses both fuel and engine factors affecting knock resistance and their contribution to higher engine efficiency and lower tailpipe CO2 emissions. Increasing compression ratios for future SI engines would be the primary response to a significant increase in fuel octane ratings. Existing LDVs would see more advanced spark timing and more efficient combustion phasing. Higher ethanol content is one available option for increasing the octane ratings of gasoline and would provide additional engine efficiency benefits for part and full load operation. An empirical calculation method is provided that allows estimation of expected vehicle efficiency, volumetric fuel economy, and CO2 emission benefits for future LDVs through higher compression ratios for different assumptions on fuel properties and engine types. Accurate "tank-to-wheel" estimates of this type are necessary for "well-to-wheel" analyses of increased gasoline octane ratings in the context of light duty vehicle transportation.

  19. High-speed fuel tracer fluorescence and OH radical chemiluminescence imaging in a spark-ignition direct-injection engine.

    Science.gov (United States)

    Smith, James D; Sick, Volker

    2005-11-01

    An innovative technique has been demonstrated to achieve crank-angle-resolved planar laser-induced fluorescence (PLIF) of fuel followed by OH* chemiluminescence imaging in a firing direct-injected spark-ignition engine. This study used two standard KrF excimer lasers to excite toluene for tracking fuel distribution. The intensified camera system was operated at single crank-angle resolution at 2000 revolutions per minute (RPM) for 500 consecutive cycles. Through this work, it has been demonstrated that toluene and OH* can be imaged through the same optical setup while similar signal levels are obtained from both species, even at these high rates. The technique is useful for studying correlations between fuel distribution and subsequent ignition and flame propagation without the limitations of phase-averaging imaging approaches. This technique is illustrated for the effect of exhaust gas recirculation on combustion and will be useful for studies of misfire causes. Finally, a few general observations are presented as to the effect of preignition fuel distribution on subsequent combustion.

  20. Modelling piloted ignition of wood and plastics.

    Science.gov (United States)

    van Blijderveen, Maarten; Bramer, Eddy A; Brem, Gerrit

    2012-09-01

    To gain insight in the startup of an incinerator, this article deals with piloted ignition. A newly developed model is described to predict the piloted ignition times of wood, PMMA and PVC. The model is based on the lower flammability limit and the adiabatic flame temperature at this limit. The incoming radiative heat flux, sample thickness and moisture content are some of the used variables. Not only the ignition time can be calculated with the model, but also the mass flux and surface temperature at ignition. The ignition times for softwoods and PMMA are mainly under-predicted. For hardwoods and PVC the predicted ignition times agree well with experimental results. Due to a significant scatter in the experimental data the mass flux and surface temperature calculated with the model are hard to validate. The model is applied on the startup of a municipal waste incineration plant. For this process a maximum allowable primary air flow is derived. When the primary air flow is above this maximum air flow, no ignition can be obtained.

  1. Spark Ignition of Combustible Vapor in a Plastic Bottle as a Demonstration of Rocket Propulsion

    Science.gov (United States)

    Mattox, J. R.

    2017-01-01

    I report an innovation that provides a compelling demonstration of rocket propulsion, appropriate for students of physics and other physical sciences. An electrical spark is initiated from a distance to cause the deflagration of a combustible vapor mixed with air in a lightweight plastic bottle that is consequently propelled as a rocket by the release of combustion products, i.e., a "whoosh rocket." My recommendation is that the standard fuel for pedagogical whoosh demonstrations be isopropanol, and the recommended vessel is the 3.8-L high-density polyethylene (HDPE) bottle.

  2. On-board diagnostics of fully variable valve actuator systems in spark-ignited combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Sarac, Ipek

    2010-07-01

    Variable valve actuation (VVA) is being employed in contemporary engines to improve fuel consumption, torque characteristics and emissions of combustion engines by enabling the realization of different combustion strategies. Fully variable valve actuation (FVVA) makes it possible to apply a wider range of strategies (e.g., homogenous charge compression ignition (HCCI), dethrottling, internal residual gas mechanism, 2/4 Stroke Switching). With FVVA, the gas exchange valves can be actuated at arbitrary points in time, with separate variable lifting for the intake and exhaust valves of each cylinder. Making FVVA systems ready for the market requires to provide the system with appropriate fault-diagnostic functionality. Additional degrees of freedom of FVVA systems introduce different fault cases which have to be considered in terms of their emission relevance within the scope of diagnostics standards such as On-Board Diagnosis II (OBD II). The faults and their effects on emissions have not been analyzed by any other study, yet. To fill this gab, here the possible faults are generated using a four-cylinder gasoline camless test bench engine. Measurements are carried out using different strategies at low loads, namely dethrottling with early intake valve closing and combining high internal residual gas with dethrottling. Each fault case is thoroughly analyzed, and the emission-relevant faults are pointed out for initial consideration. A trivial approach to diagnose fully variable valve actuators is to introduce position sensors for each actuator to track the valve lift curve. However, this approach increases the cost of the system undesirably. Thus, here alternative methods are explored such as indirect use of common powertrain sensors. Considering that active diagnosis may lead to suboptimal engine control schemes, the possibilities of fault detection and isolation are investigated without relying on active diagnosis. Air path sensors are affected foremost by any

  3. Spark ignition engine performance and emissions in a high compression engine using biogas and methane mixtures without knock occurrence

    Directory of Open Access Journals (Sweden)

    Gómez Montoya Juan Pablo

    2015-01-01

    Full Text Available With the purpose to use biogas in an internal combustion engine with high compression ratio and in order to get a high output thermal efficiency, this investigation used a diesel engine with a maximum output power 8.5 kW, which was converted to spark ignition mode to use it with gaseous fuels. Three fuels were used: Simulated biogas, biogas enriched with 25% and 50% methane by volume. After conversion, the output power of the engine decreased by 17.64% when using only biogas, where 7 kW was the new maximum output power of the engine. The compression ratio was kept at 15.5:1, and knocking did not occur during engine operation. Output thermal efficiency operating the engine in SI mode with biogas enriched with 50% methane was almost the same compared with the engine running in diesel-biogas dual mode at full load and was greater at part loads. The dependence of the diesel pilot was eliminated when biogas was used in the engine converted in SI mode. The optimum condition of experiment for the engine without knocking was using biogas enriched with 50% methane, with 12 degrees of spark timing advance and equivalence ratio of 0.95, larger output powers and higher values of methane concentration lead the engine to knock operation. The presence of CO2 allows operating engines at high compression ratios with normal combustion conditions. Emissions of nitrogen oxides, carbon monoxide and unburnt methane all in g/kWh decreased when the biogas was enriched with 50% methane.

  4. Investigation of combustion, performance and emission characteristics of 2-stroke and 4-stroke spark ignition and CAI/HCCI operations in a DI gasoline

    OpenAIRE

    Y. Zhang; Zhao, H.

    2014-01-01

    In order to develop more efficient and cleaner gasoline engines, a number of new engine operating strategies have been proposed and researched on different engines, including the spark ignition (SI) and controlled autoignition (CAI) or HCCI in both 2-stroke and 4-stroke cycles in a poppet valve engine. In this work, a single cylinder direct injection gasoline engine equipped with an electro-hydraulic valve-train system has been commissioned and used to achieve seven different operating modes,...

  5. The influence of CO2 in biogas flammability limit and laminar burning velocity in spark ignited premix combustion at various pressures

    Science.gov (United States)

    Anggono, W.; Wardana, I. N. G.; Lawes, M.; Hughes, K. J.; Wahyudi, S.; Hamidi, N.; Hayakawa, A.

    2016-03-01

    Biogas is an alternative energy source that is sustainable and renewable containing more than 50% CH4 and its biggest impurity or inhibitor is CO2. Demands for replacing fossil fuels require an improved fundamental understanding of its combustion processes. Flammability limits and laminar burning velocities are important characteristics in these processes. Thus, this research focused on the effects of CO2 on biogas flammability limits and laminar burning velocities in spark ignited premixed combustion. Biogas was burned in a spark ignited spherical combustion bomb. Spherically expanding laminar premixed flames, freely propagating from spark ignition in initial, were continuously recorded by a high-speed digital camera. The combustion bomb was filled with biogas-air mixtures at various pressures, CO2 levels and equivalence ratios (ϕ) at ambient temperature. The results were also compared to those of the previous study into inhibitorless biogas (methane) at various pressures and equivalence ratios (ϕ). Either the flammable areas become narrower with increased percentages of carbon dioxide or the pressure become lower. In biogas with 50% CO2 content, there was no biogas flame propagation for any equivalence ratio at reduced pressure (0.5 atm). The results show that the laminar burning velocity at the same equivalence ratio declined in respect with the increased level of CO2. The laminar burning velocities were higher at the same equivalence ratio by reducing the initial pressure.

  6. Effect of Operating Conditions on Pollutants Concentration Emitted from a Spark Ignition Engine Fueled with Gasoline Bioethanol Blends

    Directory of Open Access Journals (Sweden)

    Haroun A. K. Shahad

    2015-01-01

    Full Text Available This study is an experimental investigation of the effect of bioethanol gasoline blending on exhaust emissions in terms of carbon dioxide CO2, carbon monoxide CO, unburnt hydrocarbons UHC, and nitric oxide NOx of a spark ignition engine. Tests are conducted at controlled throttle and variable speed condition over the range of 1200 to 2000 rpm with intervals 400 rpm. Different compression ratios are tested for each speed, namely (7,8,10, and 11. Pure gasoline and bioethanol gasoline blends are used. The bioethanol used is produced from Iraqi date crop (Zehdi. Blending is done on energy replacement bases. Ethanol energy ratio (EER used is 5%, 10%, and 15%. At each of the three designated engine speeds, the torque is set as 0, 3, 7, 10, and 14 N·m. It is found that ethanol blending reduces CO and UHC concentration in the exhaust gases by about 45% and 40.15%, respectively, and increases NOx and CO2 concentrations in the exhaust gases by about 16.18% and 7.5%, respectively. It is found also that load and speed increase causes an increase in CO2 and NOx concentrations and reduces CO and UHC concentrations. It is also found that increasing the compression ratio causes the emissions of CO2 and NOx to decrease and those of CO and UHC to increase.

  7. Study on waste heat recovery from exhaust gas spark ignition (S.I. engine using steam turbine mechanism

    Directory of Open Access Journals (Sweden)

    Talib Kamarulhelmy

    2017-01-01

    Full Text Available The issue of global warming has pushed the effort of researchers not only to find alternative renewable energy, but also to improve the machine’s energy efficiency. This includes the utilization of waste energy into ‘useful energy’. For a vehicle using internal combustion engine (ICE, the waste energy produce by exhaust gas can be utilize to ‘useful energy’ up to 34%. The energy from the automotive exhaust can be harness by implementing heat pipe heat exchanger in the automotive system. In order to maximize the amount of waste energy that can be turned to ‘useful energy’, the used of appropriate fluid in the heat exchanger is important. In this study, the fluid used is water, thus converting the fluid into steam and thus drive the turbine that coupling with generator. The paper will explore the performance of a naturally aspirated spark ignition (S.I. engine equipped with waste heat recovery mechanism (WHRM that used water as the heat absorption medium. The experimental and simulation test suggest that the concept is thermodynamically feasible and could significantly enhance the system performance depending on the load applied to the engine.

  8. Investigation of emissions characteristics of secondary butyl alcohol-gasoline blends in a port fuel injection spark ignition engine

    Directory of Open Access Journals (Sweden)

    Yusri I.M.

    2017-01-01

    Full Text Available Exhaust emissions especially from light duty gasoline engine are a major contributor to air pollution due to the large number of vehicles on the road. The purpose of this study is to experimentally analyse the exhaust pollutant emissions of a four-stroke port fuel spark ignition engines operating using secondary butyl alcohol–gasoline blends by percentage volume of 5% (GBu5, 10% (GBu10 and 15% (GBu15 of secondary butyl- alcohol (2-butanol additives in gasoline fuels at 50% of wide throttle open. The exhaust emissions characteristics of the engine using blended fuels was compared to the exhaust emissions of the engine with gasoline fuels (G100 as a reference fuels. Exhaust emissions analysis results show that all of the blended fuels produced lower CO by 8.6%, 11.6% and 24.8% for GBu5, GBu10 and GBu15 respectively from 2500 to 4000 RPM, while for HC, both GBu10 and GBu15 were lower than that G100 fuels at all engine speeds. In general, when the engine was operated using blended fuels, the engine produced lower CO and HC, but higher CO2.

  9. Investigations on the effects of ethanol–methanol–gasoline blends in a spark-ignition engine: Performance and emissions analysis

    Directory of Open Access Journals (Sweden)

    Ashraf Elfasakhany

    2015-12-01

    Full Text Available This study discusses performance and exhaust emissions from spark-ignition engine fueled with ethanol–methanol–gasoline blends. The test results obtained with the use of low content rates of ethanol–methanol blends (3–10 vol.% in gasoline were compared to ethanol–gasoline blends, methanol–gasoline blends and pure gasoline test results. Combustion and emission characteristics of ethanol, methanol and gasoline and their blends were evaluated. Results showed that when the vehicle was fueled with ethanol–methanol–gasoline blends, the concentrations of CO and UHC (unburnt hydrocarbons emissions were significantly decreased, compared to the neat gasoline. Methanol–gasoline blends presented the lowest emissions of CO and UHC among all test fuels. Ethanol–gasoline blends showed a moderate emission level between the neat gasoline and ethanol–methanol–gasoline blends, e.g., ethanol–gasoline blends presented lower CO and UHC emissions than those of the neat gasoline but higher emissions than those of the ethanol–methanol–gasoline blends. In addition, the CO and UHC decreased and CO2 increased when ethanol and/or methanol contents increased in the fuel blends. Furthermore, the effects of blended fuels on engine performance were investigated and results showed that methanol–gasoline blends presents the highest volumetric efficiency and torque; ethanol–gasoline blends provides the highest brake power, while ethanol–methanol–gasoline blends showed a moderate level of volumetric efficiency, torque and brake power between both methanol–gasoline and ethanol–gasoline blends; gasoline, on the other hand, showed the lowest volumetric efficiency, torque and brake power among all test fuels.

  10. THE EFFECT OF ADDING HYDROGEN ON THE PERFORMANCE AND THE CYCLIC VARIABILITY OF A SPARK IGNITION ENGINE POWERED BY NATURAL GAS

    Directory of Open Access Journals (Sweden)

    Andrej Chríbik

    2014-02-01

    Full Text Available This paper deals with the influence of blending hydrogen (from 0 to 50% vol. on the parameters and the cyclic variability of a Lombardini LGW702 combustion engine powered by natural gas. The experimental measurements were carried out at various air excess ratios and at various angles of spark advance, at an operating speed of 1500 min−1. An analysis of the combustion pressure showed that as the proportion of hydrogen in the mixture increases, the maximum pressure value also increases. However, at the same time the cyclic variability decreases. Both the ignition-delay period and the period of combustion of the mixture become shorter, which requires optimization of the spark advance angle for various proportions of hydrogen in the fuel. The increasing proportion of hydrogen extends the flammability limit to the area of lean-burn mixtures and, at the same time, the coefficient of cyclic variability of the mean indicated pressure decreases.

  11. On-board diagnosis of emission control system malfunctions in electronically controlled spark ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Azzoni, P.M. [ENEA, Bologna (Italy); Rizzoni, G. [Nuclear Materials and Equipment Corp., Apollo, PA (United States). Energy Conversion Div.; Minelli, G. [Bologna Univ. (Italy). Facolta di Ingegneria

    1993-09-01

    This paper discusses simulation and experimental results of a study aimed at diagnosing faults associated with an automotive engine exhaust emissions control system. Parity space methods are applied to a model of the engine intake, fueling, combustion and exhaust dynamics to diagnose faults in sensors and actuators used by the exhaust emissions control system. The results indicate that a mix of linear dynamic and nonlinear static models permit the design of an effective diagnostic strategy.

  12. Co-Optimization of Fuels & Engines (Co-Optima) Initiative: Recent Progress on Light-Duty Boosted Spark-Ignition Fuels/Engines

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, John

    2017-07-03

    This presentation reports recent progress on light-duty boosted spark-ignition fuels/engines being developed under the Co-Optimization of Fuels and Engines initiative (Co-Optima). Co-Optima is focused on identifying fuel properties that optimize engine performance, independent of composition, allowing the market to define the best means to blend and provide these fuels. However, in support of this, we are pursuing a systematic study of blendstocks to identify a broad range of feasible options, with the objective of identifying blendstocks that can provide target ranges of key fuel properties, identifying trade-offs on consistent and comprehensive basis, and sharing information with stakeholders.

  13. Integrated thermodynamic model for ignition target performance

    Directory of Open Access Journals (Sweden)

    Springer P.T.

    2013-11-01

    Full Text Available We have derived a 3-dimensional synthetic model for NIF implosion conditions, by predicting and optimizing fits to a broad set of x-ray and nuclear diagnostics obtained on each shot. By matching x-ray images, burn width, neutron time-of-flight ion temperature, yield, and fuel ρr, we obtain nearly unique constraints on conditions in the hotspot and fuel in a model that is entirely consistent with the observables. This model allows us to determine hotspot density, pressure, areal density (ρr, total energy, and other ignition-relevant parameters not available from any single diagnostic. This article describes the model and its application to National Ignition Facility (NIF tritium–hydrogen–deuterium (THD and DT implosion data, and provides an explanation for the large yield and ρr degradation compared to numerical code predictions.

  14. Evaporate prediction and compensation of intake port wall-wetting fuel film for spark ignition engines fueled with ethanol-gasoline blends

    Institute of Scientific and Technical Information of China (English)

    Dong-wei YAO; Xin-chen LING; Feng WU

    2012-01-01

    The fuel dynamic transfer process,including fuel injection,fuel film deposition and evaporation in the intake port,was analyzed for spark ignition (SI) engines with port fuel injection (PFI).The influence of wall-wetting fuel film,especially its evaporation rate,upon the air-fuel ratio of in-cylinder mixtures was also discussed.According to the similarity principle,Fick's law,the ideal gas equation and the Gilliland correlation,an evaporate prediction model of wall-wetting fuel film was set up and an evaporate prediction based dynamic fuel film compensator was designed.Through engine cold start tests,the wall-wetting temperature,which is the key input of the fuel film evaporate prediction model,was also modeled and predicted.Combined with the experimental data of the evaporation characteristics of ethanol-gasoline blends and engine calibration tests,all the parameters of the wall-wetting fuel film evaporate prediction model used in the fuel film compensator were identified.Square-wave disturbance tests of fuel injection showed that with the help of the fuel film compensator the response of the in-cylinder air-fuel ratio was significantly improved and the real air-fuel ratio always closely matched the expected ratio.The fuel film compensator was then integrated into the final air-fuel ratio controller,and the engine tests showed that the air-fuel ratio control error was less than 2% in steady-state conditions,and less than 4%in transient conditions.The fuel film compensator also showed good adaptability to different ethanol-gasoline blends.

  15. Performance and emissions assessment of n-butanol–methanol–gasoline blends as a fuel in spark-ignition engi

    Directory of Open Access Journals (Sweden)

    Ashraf Elfasakhany

    2016-09-01

    Full Text Available The sleek of using alternatives to gasoline fuel in internal combustion engines becomes a necessity as the environmental problems of fossil fuels as well as their depleted reserves. This research presents an experimental investigation into a new blended fuel; the effects of n-butanol–methanol–gasoline fuel blends on the performance and pollutant emissions of an SI (spark-ignition engine were examined. Four test fuels (namely 0, 3, 7 and 10 volumetric percent of n-butanol–methanol blends at equal rates, e.g., 0%, 1.5%, 3.5% and 5% for n-butanol and methanol, in gasoline were investigated in an engine speed range of 2600–3400 r/min. In addition, the dual alcohol (methanol and n-butanol–gasoline blends were compared with single alcohol (n-butanol–gasoline blends (for the first time as well as with the neat gasoline fuel in terms of performance and emissions. The experimental results showed that the addition of low content rates of n-butanol–methanol to neat gasoline adversely affects the engine performance and exhaust gas emissions as compared to the results of neat gasoline and single alcohol–gasoline blends; in particular, a reduction in engine volumetric efficiency, brake power, torque, in-cylinder pressure, exhaust gas temperature and CO2 emissions and an increase in concentrations of CO and UHC (unburned hydrocarbons emissions were observed for the dual alcohols. However, higher rates of n-butanol–methanol blended in gasoline were observed to improve the SI engine performance parameters and emission concentration. Oppositely the higher rates of single alcohol–gasoline blends were observed to provide adverse results, e.g., higher emissions and lower performance than those of lower rates of single alcohol. Finally, dual alcohol–gasoline blends could exceed (i.e. provide higher performance and lower emissions single alcohol–gasoline blends and pure gasoline at higher rates (>10 vol.% in the blend and, in turn, it is

  16. Kinetic model for DT ignition and burn in ICF targets

    Energy Technology Data Exchange (ETDEWEB)

    Anisimov, S.I.; Oparin, A.M.; Meyer-ter-Vehn, J. [Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany)]|[L.D. Landau Institute for Theoretical Physics, 117940 Moscow (Russia)

    1996-05-01

    Ignition and burn of DT targets is studied taking into account kinetic effects. Kinetic equations describing the interaction of the high-energy reaction products with target plasma are solved using the particle-in-cell (PIC) code for collisional plasma. Volume and spark ignition configurations are simulated for initial temperatures and {l_angle}{rho}{ital R}{r_angle} values of practical interest and target masses between 0.1 and 10 mg. Optically thick configurations igniting at temperatures below 5 keV are considered. Burn of the targets with reduced tritium content is simulated. It was shown that, for 25{percent} tritium concentration, the energy output is reduced only by 15{percent}. {copyright} {ital 1996 American Institute of Physics.}

  17. Spark ignition engine control: estimation and prediction of the in-cylinder mass and chemical species; Controle moteur a allumage commande: estimation / prediction de la masse et de la composition du melange enferme dans le cylindre

    Energy Technology Data Exchange (ETDEWEB)

    Giansetti, P.

    2005-09-15

    Spark ignition engine control has become a major issue regarding compliance with emissions legislation while ensuring driving comfort. The objective of this thesis was to estimate the mass and composition of gases inside the cylinder of an engine based on physics in order to insure better control of transient phases taking into account residual gases as well as exhaust gas recirculation. Residual gas fraction has been characterized using two experiments and one CFD code. A model has been validated experimentally and integrated into an observer which predicts pressure and temperature inside the manifold. The predictions of the different gas flows and the chemical species inside the cylinder are deduced. A closed loop observer has been validated experimentally and in simulation. Moreover, an algorithm estimating the fresh and burned gas mass from the cylinder pressure has been proposed in order to obtain the information cycle by cycle and cylinder by cylinder. (author)

  18. DESIGN OF A HIGH COMPRESSION, DIRECT INJECTION, SPARK-IGNITION, METHANOL FUELED RESEARCH ENGINE WITH AN INTEGRAL INJECTOR-IGNITION SOURCE INSERT, SAE PAPER 2001-01-3651

    Science.gov (United States)

    A stratified charge research engine and test stand were designed and built for this work. The primary goal of this project was to evaluate the feasibility of using a removal integral injector ignition source insert which allows a convenient method of charging the relative locat...

  19. Prediction on Power Produced from Power Turbine as a Waste Heat Recovery Mechanism on Naturally Aspirated Spark Ignition Engine Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Safarudin Gazali Herawan

    2016-01-01

    Full Text Available The waste heat from exhaust gases represents a significant amount of thermal energy, which has conventionally been used for combined heating and power applications. This paper explores the performance of a naturally aspirated spark ignition engine equipped with waste heat recovery mechanism (WHRM in a sedan car. The amount of heat energy from exhaust is presented and the experimental test results suggest that the concept is thermodynamically feasible and could significantly enhance the system performance depending on the load applied to the engine. However, the existence of WHRM affects the performance of engine by slightly reducing the power. The simulation method is created using an artificial neural network (ANN which predicts the power produced from the WHRM.

  20. INVESTIGATION OF COMBUSTION, PERFORMANCE AND EMISSION CHARACTERISTICS OF SPARK IGNITION ENGINE FUELLED WITH BUTHANOL – GASOLINE MIXTURE AND A HYDROGEN ENRICHED AIR

    Directory of Open Access Journals (Sweden)

    Alfredas Rimkus

    2016-09-01

    Full Text Available In this study, spark ignition engine fuelled with buthanol-gasoline mixture and a hydrogen-enriched air was investigated. Engine performance, emissions and combustion characteristics were investigated with different buthanol (10% and 20% by volume gasoline mixtures and additionally supplied oxygen and hydrogen (HHO gas mixture (3.6 l/min in the sucked air. Hydrogen, which is in the HHO gas, improves gasoline and gasoline-buthanol mixture combustion, increases indicated pressure during combustion phase and decreases effective specific fuel consumption. Buthanol addition decreases the rate of heat release, the combustion temperature and pressure are lower which have an influence on lower nitrous oxide (NOx emission in exhaust gases. Buthanol lowers hydrocarbon (HC formation, but it increases carbon monoxide (CO concentration and fuel consumption. Combustion process analysis was carried out using AVL BOOST software. Experimental research and combustion process numerical simulation showed that using balanced buthanol and hydrogen addition, optimal efficient and ecological parameters could be achieved when engine is working with optimal spark timing, as it would work on gasoline fuel.

  1. Emission characteristics of iso-propanol/gasoline blends in a spark-ignition engine combined with exhaust gas re-circulation

    Directory of Open Access Journals (Sweden)

    Gong Jing

    2014-01-01

    Full Text Available Experiments were carried out in a spark-ignition engine fueled with iso-propanol/gasoline blends. Emission characteristics of this engine were investigated experimentally, including gaseous emissions (HC, CO, NOx and particulate matter emission in term of number and size distributions. The effects of different iso-propanol percentages, loads and exhaust gas recirculation rates on emissions were analyzed. Results show that the introduction of exhaust gas recirculation reduces the NOx emission and NOx emission gives the highest value at full load condition. HC and CO emissions present inconspicuous variations at all the loads except the load of 10%. Additionally, HC emission shows a sharp increase for pure propanol when the exhaust gas recirculation rate is up to 5%, while little variation is observed at lager exhaust gas recirculation rates. Moreover, the particulate matter number concentration increases monotonically with the increase of load and the decrease of exhaust gas recirculation rate. There exists a critical spark timing that produces the highest particulate matter number concentration at all the blending ratios.

  2. Laser diagnostic and plasma technological fundamentals of emission and fuel consumption reduction in DI internal combustion engines. Investigation of a plasma ignition system for DI spark ignition engines. Final report; Laserdiagnostische und plasmatechnologische Grundlagen zur Verminderung von Emissionen und Kraftstoffverbrauch von DI-Verbrennungsmotoren. Untersuchung eines Plasmazuendsystems fuer DI-Ottomotoren. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Lepperhoff, G.; Geiger, J.; Wolters, P.; Boewing, R.; Neff, W.

    2000-07-01

    Misfire in stratified DI spark ignition engines may result from cyclic variations of the mixture near the spark plugs. More stable ignition is expected from an initiation of inflammation in a volume range which is significantly larger than the ignition spark of a transistor coil ignition system. the research project investigated the interdependence between electric power supply and the development and propagation of the plasma on a plasma spark plug in space and time. Goals of development are: Development of a system for test stand testing (no electromagnetic interference in the electronic system of the test stand; long-term stability and low variation of the ignition energy; low electrode wear); higher thermal efficiency than conventional transistor coil ignition systems; improved ignition of slow-reacting mixtures with ignition energies below 120 mJ; 'remote' inflammation across a gap of several mm inside the combustion space. [German] Bei geschichtet betriebenen DI-Ottomotoren koennen zyklische Schwankungen in der Gemischzusammensetzung in Zuendkerzennaehe zu Verbrennungsaussetzern fuehren. Durch die Initiierung der Entflammung in einem Volumenbereich, der im Vergleich zum Zuendfunken einer Transistorspulenzuendung (TSZ) deutlich groesser ist, wird eine stabilere Verbrennungseinleitung erwartet. In diesem Forschungsvorhaben liegt der Schwerpunkt auf der Untersuchung des Zusammenhangs zwischen der elektrischen Leistungseinkopplung und der zeitlich-raeumlichen Entstehung und Ausbreitung des Plasmas an einer Plasmazuendkerze. Die wesentlichen Ziele sind: - Darstellung eines pruefstandtauglichen Systems fuer den Betrieb an DI-Ottomotoren (keine elektromagnetische Stoerung der Pruefstandelektronik; Langzeitstabilitaet der Zuendenergie bei kleiner Schwankungsbreite; niedriger Verschleiss der Elektroden) - hoeherer thermischer Wirkungsgrad als konventionelle Transistorspulenzuendungen - verbesserte Zuendung reaktionstraeger Gemische mit Zuendenergien <120 m

  3. Signal Analysis of Automotive Engine Spark Ignition System using Case-Based Reasoning (CBR) and Case-based Maintenance (CBM)

    Science.gov (United States)

    Huang, H.; Vong, C. M.; Wong, P. K.

    2010-05-01

    With the development of modern technology, modern vehicles adopt electronic control system for injection and ignition. In traditional way, whenever there is any malfunctioning in an automotive engine, an automotive mechanic usually performs a diagnosis in the ignition system of the engine to check any exceptional symptoms. In this paper, we present a case-based reasoning (CBR) approach to help solve human diagnosis problem. Nevertheless, one drawback of CBR system is that the case library will be expanded gradually after repeatedly running the system, which may cause inaccuracy and longer time for the CBR retrieval. To tackle this problem, case-based maintenance (CBM) framework is employed so that the case library of the CBR system will be compressed by clustering to produce a set of representative cases. As a result, the performance (in retrieval accuracy and time) of the whole CBR system can be improved.

  4. Knock Resistance and Fine Particle Emissions for Several Biomass-Derived Oxygenates in a Direct-Injection Spark-Ignition Engine

    Energy Technology Data Exchange (ETDEWEB)

    Ratcliff, Matthew A.; Burton, Jonathan; Sindler, Petr; Christensen, Earl; Fouts, Lisa; Chupka, Gina M.; McCormick, Robert L.

    2016-04-01

    Several high octane number oxygenates that could be derived from biomass were blended with gasoline and examined for performance properties and their impact on knock resistance and fine particle emissions in a single cylinder direct-injection spark-ignition engine. The oxygenates included ethanol, isobutanol, anisole, 4-methylanisole, 2-phenylethanol, 2,5-dimethyl furan, and 2,4-xylenol. These were blended into a summertime blendstock for oxygenate blending at levels ranging from 10 to 50 percent by volume. The base gasoline, its blends with p-xylene and p-cymene, and high-octane racing gasoline were tested as controls. Relevant gasoline properties including research octane number (RON), motor octane number, distillation curve, and vapor pressure were measured. Detailed hydrocarbon analysis was used to estimate heat of vaporization and particulate matter index (PMI). Experiments were conducted to measure knock-limited spark advance and particulate matter (PM) emissions. The results show a range of knock resistances that correlate well with RON. Molecules with relatively low boiling point and high vapor pressure had little effect on PM emissions. In contrast, the aromatic oxygenates caused significant increases in PM emissions (factors of 2 to 5) relative to the base gasoline. Thus, any effect of their oxygen atom on increasing local air-fuel ratio was outweighed by their low vapor pressure and high double-bond equivalent values. For most fuels and oxygenate blend components, PMI was a good predictor of PM emissions. However, the high boiling point, low vapor pressure oxygenates 2-phenylethanol and 2,4-xylenol produced lower PM emissions than predicted by PMI. This was likely because they did not fully evaporate and combust, and instead were swept into the lube oil.

  5. Injection systems for spark ignition engines within the limits of the optimization of particle emissions and CO{sub 2} optimization; Einspritzsysteme fuer Otto-Motoren im Spannungsfeld zwischen Partikelemissions- und CO{sub 2}-Optimierung

    Energy Technology Data Exchange (ETDEWEB)

    Frenzel, Holger; Roesel, Gerd; Achleitner, Erwin; Baecker, Harald; Tichy, Milos [Continental Automotive GmbH, Regensburg (Germany)

    2011-07-01

    The spark ignition engine is worldwide the dominant driving unit. Due to the excellent ratio between cost and performance the spark ignition engine has to be further developed for the future market requirements like ''fun to drive'', low fuel consumption and stringent emission targets especially low particulate number. To reach these contradictory targets the fuel injection sytem, in particular for DI engines, plays a major role. Fuel metering and spray preparation are the key parameters for further improvement. Continental offers sustainable innovations for DI injection systems. This paper deals with requirements and solutions for gasoline fuel metering. Main functional parameters are discussed on market requirements. This is followed by a system approach. (orig.)

  6. Development of a simulation model for compression ignition engine running with ignition improved blend

    Directory of Open Access Journals (Sweden)

    Sudeshkumar Ponnusamy Moranahalli

    2011-01-01

    Full Text Available Department of Automobile Engineering, Anna University, Chennai, India. The present work describes the thermodynamic and heat transfer models used in a computer program which simulates the diesel fuel and ignition improver blend to predict the combustion and emission characteristics of a direct injection compression ignition engine fuelled with ignition improver blend using classical two zone approach. One zone consists of pure air called non burning zone and other zone consist of fuel and combustion products called burning zone. First law of thermodynamics and state equations are applied in each of the two zones to yield cylinder temperatures and cylinder pressure histories. Using the two zone combustion model the combustion parameters and the chemical equilibrium composition were determined. To validate the model an experimental investigation has been conducted on a single cylinder direct injection diesel engine fuelled with 12% by volume of 2- ethoxy ethanol blend with diesel fuel. Addition of ignition improver blend to diesel fuel decreases the exhaust smoke and increases the thermal efficiency for the power outputs. It was observed that there is a good agreement between simulated and experimental results and the proposed model requires low computational time for a complete run.

  7. A Review of Sub-Scale Test Methods to Evaluate the Friction and Wear of Ring and Liner Materials for Spark- and Compression Ignition Engines

    Energy Technology Data Exchange (ETDEWEB)

    Blau, P.J.

    2002-01-22

    A review was conducted of past laboratory-scale test methods and to assess their validity for ranking materials and lubricants for use as piston and liner materials in compression-ignition (CI) and spark-ignition (SI) engines. Most of the previous work was aimed at simulating SI engine environments. This report begins with a discussion of the numerous factors that can affect the validity of an approach to simulating engine conditions in a laboratory. These include not only mechanical, chemical and thermal factors, but also human factors as regards how the vehicle is operated and maintained. The next section provides an annotated review of open literature publications that address the issues of laboratory simulation of engine components. A comparison of these studies indicates a lack of sufficient standardization in procedures to enable a systematic comparison of one publication to another. There were just a few studies that compared several laboratory test methods to engine test results, and these indicated that some test methods correlate, at least qualitatively, better than others. The last section provides a series of recommendations for improving the accuracy and validity of laboratory-scale simulations of engine behavior. It became clear that much of the engine wear damage occurs during start-up when the engine is cold, and this calls into the question the usefulness of test methods that attempt to simulate steady-state running conditions. It is recommended that a new standard test method, perhaps developed with the help of the ASTM wear and erosion committee, be developed. It would use cold start-up conditions in the presence of degraded oil, or simulated degraded oil.

  8. Performance of direct injection methanol engine using the fuel jet impingement and diffusion. ; Comparison between the spark plug and glow plug ignitions. Nenryo funryu no shototsu kakusan wo riyoshita chokufun methanol kikan no seino. ; Spark plug oyobi glow plug chakka hoshiki no hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Kato, S.; Onishi, S.

    1993-01-20

    The purpose of this paper is to compare the performance of direct fuel injection methanol engines with the spark plug and glow plug ignition systems. These methanol engines utilize the formation of fuel-air mixture by the fuel jet impingement and diffusion. Engine performance and cylinder pressure for the both ignition systems were analyzed. Piezoelectric pressure indicator was used for the cylinder pressure measurements, and combustion analyzer was used for their analyses. In order to estimate engine performance, effects of load and engine speed were analyzed. Consequently, almost the same brake thermal efficiencies (maximum value of 42%) were obtained for both ignition systems. For the glow plug ignition system, the combustion noise and NOx emission were lower than the spark plug engine. The NOx emission did not excess 500ppm with the glow plug ignition system. In the impingement and diffusion method, both the piston attached type impingement part and cylinder head fixed type one were applicable. 4 refs., 9 figs., 2 tabs.

  9. The Effect of Various Test Parameters on the Steady Flow Test Results of a Four-Valve Spark Ignition Engine: A Tentative Approach toward Standardization

    Directory of Open Access Journals (Sweden)

    A. Mohammadebrahim

    2013-01-01

    Full Text Available The present paper is an account of an experimental analysis carried out to investigate to what extent the flow characteristics in the intake system of a 4-valve, spark ignition internal combustion engine depend on the experimental conditions at the steady flow test bench. In this respect, the study is aimed at determining the influences of the intake adaptor, test pressure, adaptor length and diameter, adaptor roughness, paddle wheel diameter, and asymmetric valves lifting on the flow coefficient and the swirl intensity measurements. In studies of this kind, researchers generally tend to adopt different test parameters to arrive at a nonuniform base to compare results from several investigations. This work is aimed at verifying the quantitative differences detected using these test parameters. The findings revealed that the swirl intensity depends on the pressure test, adaptor length, and the entry type to a significant degree. Moreover, it was observed that the intake adaptor is the most effective test parameter on the flow coefficient. Finally, the sensitivity analysis has been performed in order to investigate the experimental results and to correlate them with the test parameters.

  10. Hydrocarbon raw emission characterization of a direct-injection spark ignition engine operated with alcohol and furan-based bio fuels

    Energy Technology Data Exchange (ETDEWEB)

    Thewes, Matthias [FEV GmbH, Aachen (Germany); Mauermann, Peter; Pischinger, Stefan [RWTH Aachen Univ. (Germany). Inst. for Combustion Engines; Bluhm, Kerstin; Hollert, Henner [RWTH Aachen Univ. (Germany). Inst. for Environmental Research, Dept. of Ecosystem Analysis

    2013-06-01

    Within the Cluster of Excellence ''Tailor-Made Fuels from Biomass'' the impact of various potential bio fuels on engine combustion is studied. Besides alcohols, furan-based bio fuels have come into the focus with novel production routes to transform biomass into 2-Methylfuran or 2,5-Dimethylfuran. In the present study, the influence of these and other bio fuels on the hydrocarbon raw emission spectrum of a direct-injection spark-ignition single cylinder engine is studied experimentally by means of gas chromatographic and mass spectroscopic analysis of exhaust gas samples. The results obtained are compared to operation with conventional EN 228 gasoline fuel. This fuel showed slip of partially carcinogenic aromatic fuel molecule(s) in warm and in cold engine conditions. For the bio fuels, slip was found to be significant for the alcohol fuels. The carcinogenic molecule 1,3-Butadiene was present in the exhaust gas of all fuels. Furan as another possibly carcinogenic molecule was found at significantly higher concentrations in the exhaust gas of the furan-based bio fuels compared to conventional gasoline fuel but not in the exhaust gas of the alcohol fuels. (orig.)

  11. Application of a four-step HMX kinetic model to an impact-induced fraction ignition problems

    Energy Technology Data Exchange (ETDEWEB)

    Perry, William L [Los Alamos National Laboratory; Gunderson, Jake A [Los Alamos National Laboratory; Dickson, Peter M [Los Alamos National Laboratory

    2010-01-01

    There has been a long history of interest in the decomposition kinetics of HMX and HMX-based formulations due to the widespread use of this explosive in high performance systems. The kinetics allow us to predict, or attempt to predict, the behavior of the explosive when subjected to thermal hazard scenarios that lead to ignition via impact, spark, friction or external heat. The latter, commonly referred to as 'cook off', has been widely studied and contemporary kinetic and transport models accurately predict time and location of ignition for simple geometries. However, there has been relatively little attention given to the problem of localized ignition that results from the first three ignition sources of impact, spark and friction. The use of a zero-order single-rate expression describing the exothermic decomposition of explosives dates to the early work of Frank-Kamanetskii in the late 1930s and continued through the 60's and 70's. This expression provides very general qualitative insight, but cannot provide accurate spatial or timing details of slow cook off ignition. In the 70s, Catalano, et al., noted that single step kinetics would not accurately predict time to ignition in the one-dimensional time to explosion apparatus (ODTX). In the early 80s, Tarver and McGuire published their well-known three step kinetic expression that included an endothermic decomposition step. This scheme significantly improved the accuracy of ignition time prediction for the ODTX. However, the Tarver/McGuire model could not produce the internal temperature profiles observed in the small-scale radial experiments nor could it accurately predict the location of ignition. Those factors are suspected to significantly affect the post-ignition behavior and better models were needed. Brill, et al. noted that the enthalpy change due to the beta-delta crystal phase transition was similar to the assumed endothermic decomposition step in the Tarver/McGuire model. Henson, et

  12. Mixed butanols addition to gasoline surrogates: Shock tube ignition delay time measurements and chemical kinetic modeling

    KAUST Repository

    AlRamadan, Abdullah S.

    2015-10-01

    The demand for fuels with high anti-knock quality has historically been rising, and will continue to increase with the development of downsized and turbocharged spark-ignition engines. Butanol isomers, such as 2-butanol and tert-butanol, have high octane ratings (RON of 105 and 107, respectively), and thus mixed butanols (68.8% by volume of 2-butanol and 31.2% by volume of tert-butanol) can be added to the conventional petroleum-derived gasoline fuels to improve octane performance. In the present work, the effect of mixed butanols addition to gasoline surrogates has been investigated in a high-pressure shock tube facility. The ignition delay times of mixed butanols stoichiometric mixtures were measured at 20 and 40bar over a temperature range of 800-1200K. Next, 10vol% and 20vol% of mixed butanols (MB) were blended with two different toluene/n-heptane/iso-octane (TPRF) fuel blends having octane ratings of RON 90/MON 81.7 and RON 84.6/MON 79.3. These MB/TPRF mixtures were investigated in the shock tube conditions similar to those mentioned above. A chemical kinetic model was developed to simulate the low- and high-temperature oxidation of mixed butanols and MB/TPRF blends. The proposed model is in good agreement with the experimental data with some deviations at low temperatures. The effect of mixed butanols addition to TPRFs is marginal when examining the ignition delay times at high temperatures. However, when extended to lower temperatures (T < 850K), the model shows that the mixed butanols addition to TPRFs causes the ignition delay times to increase and hence behaves like an octane booster at engine-like conditions. © 2015 The Combustion Institute.

  13. Ignition of pyrophoric powders: An entry-level model

    Science.gov (United States)

    Alymov, M. I.; Seplyarskii, B. S.; Gordopolova, I. S.

    2015-11-01

    Chemically prepared metal nanopowders are normally pyrophoric, i.e. are liable to ignite spontaneously on exposure to air because of high reactivity and developed specific surface. On the other side, reliable theoretical models for spontaneous self-ignition of fine dispersed powders at room temperature have not been suggested so far. A deeper insight into the mechanism of the phenomenon would shed new light on the critical conditions for self-inflammation and thus would provide some clues for optimization of the passivation of fine dispersed powders. In this work, we formulated and analyzed an entry-level model for ignition of pyrophoric powders. Analysis of such a model in terms of the ignition theory gave the following results. Depending on the width of the reaction zone, the ignition may get started in either one or two stages. The duration of each stage was evaluated by using the approximate methods of combustion theory. The parametric limits for the model applicability were derived and the influence of sample length on the ignition process was explored as well.

  14. Benefits and applications of laser-induced sparks in real scale model measurements

    DEFF Research Database (Denmark)

    Gómez-Bolaños, Javier; Delikaris-Manias, Symeon; Pulkki, Ville Topias

    2015-01-01

    The characteristics of using a laser-induced spark as a monopole source in scale model measurements were assessed by comparison with an electric spark and a miniature spherical loudspeaker. Room impulse responses of first order directivity sources were synthesized off-line using six spatially dis...... to synthesize room responses of directional sources, e.g., to obtain directional information about reflections inside scale models....

  15. Design and modeling of ignition targets for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Haan, S.W.; Pollaine, S.M.; Lindl, J.D.; Suter, L.J.; Berger, R.L.; Powers, L.V.; Alley, W.E.; Amendt, P.A.; Futterman, J.A.; Levedahl, W.K.; Rosen, M.D.; Rowley, D.P.; Sacks, R.A.; Shestakov, A.I.; Strobel, G.L.; Tabak, M.; Weber, S.V.; Zimmerman, G.B. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Krauser, W.J.; Wilson, D.C.; Coggeshall, S.V.; Harris, D.B.; Hoffman, N.M.; Wilde, B.H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1995-06-01

    Several targets are described that in simulations give yields of 1--30 MJ when indirectly driven by 0.9--2 MJ of 0.35 {mu}m laser light. The article describes the targets, the modeling that was used to design them, and the modeling done to set specifications for the laser system in the proposed National Ignition Facility. Capsules with beryllium or polystyrene ablators are enclosed in gold hohlraums. All the designs utilize a cryogenic fuel layer; it is very difficult to achieve ignition at this scale with a noncryogenic capsule. It is necessary to use multiple bands of illumination in the hohlraum to achieve sufficiently uniform x-ray irradiation, and to use a low-{ital Z} gas fill in the hohlraum to reduce filling of the hohlraum with gold plasma. Critical issues are hohlraum design and optimization, Rayleigh--Taylor instability modeling, and laser--plasma interactions.

  16. Reactive burn models and ignition & growth concept

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph S [Los Alamos National Laboratory; Shaw, Milton S [Los Alamos National Laboratory

    2010-01-01

    Plastic-bonded explosives are heterogeneous materials. Experimentally, shock initiation is sensitive to small amounts of porosity, due to the formation of hot spots (small localized regions of high temperature). This leads to the Ignition and Growth concept, introduced by Lee and Tarver in 1980, as the basis for reactive burn models. A homogeneized burn rate needs to account for three mesoscale physical effects (i) the density of burnt hot spots, which depends on the lead shock strength; (ii) the growth of the burn fronts triggered by hot spots, which depends on the local deflagration speed; (iii) a geometric factor that accounts for the overlap of deflagration wavelets from adjacent hot spots. These effects can be combined and the burn model defined by specifying the reaction progress variable {lambda}(t) as a function of a dimensionless reaction length {tau}{sub hs}(t)/{ell}{sub hs}, rather than by xpecifying an explicit burn rate. The length scale {ell}{sub hs} is the average distance between hot spots, which is proportional to [N{sub hs}(P{sub s})]{sup -1/3}, where N{sub hs} is the number density of hot spots activated by the lead shock. The reaction length {tau}{sub hs}(t) = {line_integral}{sub 0}{sup t} D(P(t'))dt' is the distance the burn front propagates from a single hot spot, where D is the deflagration speed and t is the time since the shock arrival. A key implementation issue is how to determine the lead shock strength in conjunction with a shock capturing scheme. They have developed a robust algorithm for this purpose based on the Hugoniot jump condition for the energy. The algorithm utilizes the time dependence of density, pressure and energy within each cell. The method is independent of the numerical dissipation used for shock capturing. It is local and can be used in one or more space dimensions. The burn model has a small number of parameters which can be calibrated to fit velocity gauge data from shock initiation experiments.

  17. Reactive burn models and ignition & growth concept

    Directory of Open Access Journals (Sweden)

    Shaw M.S.

    2011-01-01

    Full Text Available Plastic-bonded explosives are heterogeneous materials. Experimentally, shock initiation is sensitive to small amounts of porosity, due to the formation of hot spots (small localized regions of high temperature. This leads to the Ignition & Growth concept, introduced by LeeTarver in 1980, as the basis for reactive burn models. A homo- genized burn rate needs to account for three meso-scale physical effects: (i the density of active hot spots or burn centers; (ii the growth of the burn fronts triggered by the burn centers; (iii a geometric factor that accounts for the overlap of deflagration wavelets from adjacent burn centers. These effects can be combined and the burn model defined by specifying the reaction progress variable λ = g(s as a function of a dimensionless reaction length s(t = rbc/ℓbc, rather than by specifying an explicit burn rate. The length scale ℓbc(Ps = [Nbc(Ps]−1/3 is the average distance between burn centers, where Nbc is the number density of burn centers activated by the lead shock. The reaction length rbc(t = ∫t0 D(P(t′dt′ is the distance the burn front propagates from a single burn center, where D(P is the deflagration speed as a function of the local pressure and t is the time since the shock arrival. A key implementation issue is how to determine the lead shock strength in conjunction with a shock capturing scheme. We have developed a robust algorithm for this purpose based on the Hugoniot jump condition for the energy. The algorithm utilizes the time dependence of density, pressure and energy within each cell. The method is independent of the numerical dissipation used for shock capturing. It is local and can be used in one or more space dimensions. The burn model has a small number of parameters which can be calibrated to fit velocity gauge data from shock initiation experiments.

  18. 点燃式缸内直喷甲醇发动机甲醛和未燃甲醇排放特性%Formaldehyde and unburned methanol emissions from a spark-ignition direct-injection methanol engine

    Institute of Scientific and Technical Information of China (English)

    宫长明; 张自雷; 贾京龙; 崔峰云; 郑伟

    2012-01-01

    The effects of methanol injection timing, ignition timing and excess air ratio on formaldehyde and unburned methanol emissions from a spark-ignition direct-injection methanol engine under homogenous combustion mode were investigated experimentally by means of a measurement method in which the gas chromatography and the liquid chromatography were used to separate and measure formaldehyde and methanol. The results show that the methanol injection timing, ignition timing and excess air ratio affect significantly the formaldehyde and unburned methanol emissions from a spark- ignition directqnjection methanol engine. The variations in emitted formaldehyde and unburned methanol show opposite tendencies with the variations in the methanol injection timing, ignition timing and excess air ratio. Retarding methanol injection timing, advancing ignition timing and using lean mixture decrease formaldehyde emission.%基于气相色谱和液相色谱相结合的甲醛和甲醇测量方法,试验研究了点燃式缸内直喷甲醇发动机甲醇喷射正时、点火正时和过量空气系数在均质燃烧模式下对甲醛和未燃甲醇排放的影响。试验结果表明,甲醇喷射正时、点火正时和过量空气系数对该发动机甲醛和未燃甲醇排放有显著影响,并且甲醛和未燃甲醇排放随喷射正时、点火正时和过量空气系数的变化呈相反的变化趋势。推迟喷射甲醇、提前点火及采用稀混合气可以降低甲醛排放。

  19. Detailed Chemical Kinetic Reaction Mechanisms for Primary Reference Fuels for Diesel Cetane Number and Spark-Ignition Octane Number

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C K; Pitz, W J; Mehl, M; Curran, H J

    2010-03-03

    For the first time, a detailed chemical kinetic reaction mechanism is developed for primary reference fuel mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethyl nonane for diesel cetane ratings. The mechanisms are constructed using existing rules for reaction pathways and rate expressions developed previously for the primary reference fuels for gasoline octane ratings, n-heptane and iso-octane. These reaction mechanisms are validated by comparisons between computed and experimental results for shock tube ignition and for oxidation under jet-stirred reactor conditions. The combined kinetic reaction mechanism contains the submechanisms for the primary reference fuels for diesel cetane ratings and submechanisms for the primary reference fuels for gasoline octane ratings, all in one integrated large kinetic reaction mechanism. Representative applications of this mechanism to two test problems are presented, one describing fuel/air autoignition variations with changes in fuel cetane numbers, and the other describing fuel combustion in a jet-stirred reactor environment with the fuel varying from pure 2,2,4,4,6,8,8-heptamethyl nonane (Cetane number of 15) to pure n-hexadecane (Cetane number of 100). The final reaction mechanism for the primary reference fuels for diesel fuel and gasoline is available on the web.

  20. Parameter sensitivity analysis of stochastic models provides insights into cardiac calcium sparks.

    Science.gov (United States)

    Lee, Young-Seon; Liu, Ona Z; Hwang, Hyun Seok; Knollmann, Bjorn C; Sobie, Eric A

    2013-03-05

    We present a parameter sensitivity analysis method that is appropriate for stochastic models, and we demonstrate how this analysis generates experimentally testable predictions about the factors that influence local Ca(2+) release in heart cells. The method involves randomly varying all parameters, running a single simulation with each set of parameters, running simulations with hundreds of model variants, then statistically relating the parameters to the simulation results using regression methods. We tested this method on a stochastic model, containing 18 parameters, of the cardiac Ca(2+) spark. Results show that multivariable linear regression can successfully relate parameters to continuous model outputs such as Ca(2+) spark amplitude and duration, and multivariable logistic regression can provide insight into how parameters affect Ca(2+) spark triggering (a probabilistic process that is all-or-none in a single simulation). Benchmark studies demonstrate that this method is less computationally intensive than standard methods by a factor of 16. Importantly, predictions were tested experimentally by measuring Ca(2+) sparks in mice with knockout of the sarcoplasmic reticulum protein triadin. These mice exhibit multiple changes in Ca(2+) release unit structures, and the regression model both accurately predicts changes in Ca(2+) spark amplitude (30% decrease in model, 29% decrease in experiments) and provides an intuitive and quantitative understanding of how much each alteration contributes to the result. This approach is therefore an effective, efficient, and predictive method for analyzing stochastic mathematical models to gain biological insight.

  1. Ignition of Metal Powders in Combustion Products of Model Fuel

    Science.gov (United States)

    1974-11-13

    y AD/A-001 172 IGNITION OF METAL POWDERS IN COMBUSTION PRODUCTS OF MODEL FUEL A. K. Klyauzov, et al Foreign Technology...S. Air Force UNCLASSIFIED »b. s»ouc » "I»0«T TITLE IGNITION OF METAL POWDERS IN COMBUSTION PRODUCTS OF MODEL FUEL f* OCJCPIPTIVK NOTKI (Typ* o...report mnd Inclumiv «**»••) Translation S »UTMö«I|I ( Firn tSSS», rnlddl* Inltlml, faar .tarna; A. K. Klyauzov, M. M. Arsh, et al 6

  2. An investigation of the ignition probability and data analysis for the detection of relevant parameters of mechanically generated steel sparks in explosive gas/air-mixtures; Untersuchungen zur Zuendwahrscheinlichkeit und Datenanalyse zur Erfassung der Einflussgroessen mechanisch erzeugter Stahl-Schlagfunktion in explosionsfaehigen Brenngas/Luft-Gemischen

    Energy Technology Data Exchange (ETDEWEB)

    Grunewald, Thomas; Finke, Robert; Graetz, Rainer

    2010-07-01

    Mechanically generated sparks are a potential source of ignition in highly combustible areas. A multiplicity of mechanical and reaction-kinetic influences causes a complex interaction of parameters. It is only little known about their effect on the ignition probability. The ignition probability of mechanically generated sparks with a material combination of unalloyed steel/unalloyed steel and with an kinetic impact energy between 3 and 277 Nm could be determined statistically tolerable. In addition, the explosiveness of not oxidized particles at increased temperatures in excess stoichiometric mixtures was proven. A unique correlation between impact energy and ignition probability as well as a correlation of impact energy and number of separated particles could be determined. Also, a principle component analysis considering the interaction of individual particles could not find a specific combination of measurable characteristics of the particles, which correlate with a distinct increase of the ignition probability.

  3. Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

    KAUST Repository

    Alfazazi, Adamu

    2016-08-10

    The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate the ignition delay of n-dodecane and n-heptane in a constant volume combustion chamber (CVCC), which is archived in the engine combustion network (ECN) library (http://www.ca.sandia.gov/ecn). A detailed chemical kinetic model for gasoline surrogates from the Lawrence Livermore National Laboratory (LLNL) was utilized for the simulation of n-heptane and isooctane. Additional simulations were performed using an optimized gasoline surrogate mechanism from RWTH Aachen University. Validations of the simulated data were also performed with experimental results from an IQT at KAUST. For simulation of n-dodecane in the CVCC, two n-dodecane kinetic models from the literature were utilized. The primary aim of this study is to test the ability of TSL to replicate ignition timings in the IQT and the CVCC. The agreement between the model and the experiment is acceptable except for isooctane in the IQT and n-heptane and n-dodecane in the CVCC. The ability of the simulations to replicate observable trends in ignition delay times with regard to changes in ambient temperature and pressure allows the model to provide insights into the reactions contributing towards ignition. Thus, the TSL model was further employed to investigate the physical and chemical processes responsible for controlling the overall ignition under various conditions. The effects of exothermicity, ambient pressure, and ambient oxygen concentration on first stage ignition were also studied. Increasing ambient pressure and oxygen concentration was found to shorten the overall ignition delay time, but does not affect the timing of the first stage ignition. Additionally, the temperature at the end of the first stage ignition was found to increase at higher ambient pressure

  4. Acoustic Igniter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An acoustic igniter eliminates the need to use electrical energy to drive spark systems to initiate combustion in liquid-propellant rockets. It does not involve the...

  5. Acoustic Igniter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An acoustic igniter eliminates the need to use electrical energy to drive spark systems to initiate combustion in liquid-propellant rockets. It does not involve the...

  6. Modeling calcium wave based on anomalous subdiffusion of calcium sparks in cardiac myocytes.

    Directory of Open Access Journals (Sweden)

    Xi Chen

    Full Text Available Ca(2+ sparks and Ca(2+ waves play important roles in calcium release and calcium propagation during the excitation-contraction (EC coupling process in cardiac myocytes. Although the classical Fick's law is widely used to model Ca(2+ sparks and Ca(2+ waves in cardiac myocytes, it fails to reasonably explain the full-width at half maximum(FWHM paradox. However, the anomalous subdiffusion model successfully reproduces Ca(2+ sparks of experimental results. In this paper, in the light of anomalous subdiffusion of Ca(2+ sparks, we develop a mathematical model of calcium wave in cardiac myocytes by using stochastic Ca(2+ release of Ca(2+ release units (CRUs. Our model successfully reproduces calcium waves with physiological parameters. The results reveal how Ca(2+ concentration waves propagate from an initial firing of one CRU at a corner or in the middle of considered region, answer how large in magnitude of an anomalous Ca(2+ spark can induce a Ca(2+ wave. With physiological Ca(2+ currents (2pA through CRUs, it is shown that an initial firing of four adjacent CRUs can form a Ca(2+ wave. Furthermore, the phenomenon of calcium waves collision is also investigated.

  7. COMBUSTION SIMULATION IN A SPARK IGNITION ENGINE CYLINDER: EFFECTS OF AIR-FUEL RATIO ON THE COMBUSTION DURATION

    Directory of Open Access Journals (Sweden)

    Nureddin Dinler

    2010-01-01

    Full Text Available Combustion is an important subject of internal combustion engine studies. To reduce the air pollution from internal combustion engines and to increase the engine performance, it is required to increase combustion efficiency. In this study, effects of air/fuel ratio were investigated numerically. An axisymmetrical internal combustion engine was modeled in order to simulate in-cylinder engine flow and combustion. Two dimensional transient continuity, momentum, turbulence, energy, and combustion equations were solved. The k-e turbulence model was employed. The fuel mass fraction transport equation was used for modeling of the combustion. For this purpose a computational fluid dynamics code was developed by using the finite volume method with FORTRAN programming code. The moving mesh was utilized to simulate the piston motion. The developed code simulates four strokes of engine continuously. In the case of laminar flow combustion, Arrhenius type combustion equations were employed. In the case of turbulent flow combustion, eddy break-up model was employed. Results were given for rich, stoichiometric, and lean mixtures in contour graphs. Contour graphs showed that lean mixture (l = 1.1 has longer combustion duration.

  8. Experimental studies on the group ignition of a cloud of coal particles: Volume 2, Pyrolysis and ignition modeling

    Energy Technology Data Exchange (ETDEWEB)

    Annamalai, K.; Ryan, W.

    1992-01-01

    The primary objectives of this work are to formulate a model to simulate transient coal pyrolysis, ignition, and combustion of a cloud of coal particles and to compare results of the program with those reported in the literature elsewhere.

  9. COMBUSTION SIMULATION IN A SPARK IGNITION ENGINE CYLINDER: EFFECTS OF AIR-FUEL RATIO ON THE COMBUSTION DURATION

    OpenAIRE

    2010-01-01

    Combustion is an important subject of internal combustion engine studies. To reduce the air pollution from internal combustion engines and to increase the engine performance, it is required to increase combustion efficiency. In this study, effects of air/fuel ratio were investigated numerically. An axisymmetrical internal combustion engine was modeled in order to simulate in-cylinder engine flow and combustion. Two dimensional transient continuity, momentum, turbulence, energy, and combustion...

  10. Computational Modeling in Support of the National Ignition Facilty Operations

    CERN Document Server

    Shaw, M J; Haynam, C A; Williams, W H

    2001-01-01

    Numerical simulation of the National Ignition Facility (NIF) laser performance and automated control of the laser setup process are crucial to the project's success. These functions will be performed by two closely coupled computer code: the virtual beamline (VBL) and the laser performance operations model (LPOM).

  11. Computational Modeling in Support of National Ignition Facility Operations

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, M J; Sacks, R A; Haynam, C A; Williams, W H

    2001-10-23

    Numerical simulation of the National Ignition Facility (NIF) laser performance and automated control of laser setup process are crucial to the project's success. These functions will be performed by two closely coupled computer codes: the virtual beamline (VBL) and the laser operations performance model (LPOM).

  12. Modeling spatio-temporal wildfire ignition point patterns

    Science.gov (United States)

    Amanda S. Hering; Cynthia L. Bell; Marc G. Genton

    2009-01-01

    We analyze and model the structure of spatio-temporal wildfire ignitions in the St. Johns River Water Management District in northeastern Florida. Previous studies, based on the K-function and an assumption of homogeneity, have shown that wildfire events occur in clusters. We revisit this analysis based on an inhomogeneous K-...

  13. Experimental and Numerical Study of Jet Controlled Compression Ignition on Combustion Phasing Control in Diesel Premixed Compression Ignition Systems

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2014-07-01

    Full Text Available In order to directly control the premixed combustion phasing, a Jet Controlled Compression Ignition (JCCI for diesel premixed compression ignition systems is investigated. Experiments were conducted on a single cylinder natural aspirated diesel engine without EGR at 3000 rpm. Numerical models were validated by load sweep experiments at fixed spark timing. Detailed combustion characteristics were analyzed based on the BMEP of 2.18 bar. The simulation results showed that the high temperature jets of reacting active radical species issued from the ignition chamber played an important role on the onset of combustion in the JCCI system. The combustion of diesel pre-mixtures was initiated rapidly by the combustion products issued from the ignition chamber. Moreover, the flame propagation was not obvious, similar to that in Pre-mixed Charge Compression Ignition (PCCI. Consequently, spark timing sweep experiments were conducted. The results showed a good linear relationship between spark timing in the ignition chamber and CA10 and CA50, which indicated the ability for direct combustion phasing control in diesel PCCI. The NOx and soot emissions gradually changed with the decrease of spark advance angle. The maximum reduction of NOx and soot were both over 90%, and HC and CO emissions were increased.

  14. Nanostructured energetic composites: synthesis, ignition/combustion modeling, and applications.

    Science.gov (United States)

    Zhou, Xiang; Torabi, Mohsen; Lu, Jian; Shen, Ruiqi; Zhang, Kaili

    2014-03-12

    Nanotechnology has stimulated revolutionary advances in many scientific and industrial fields, particularly in energetic materials. Powder mixing is the simplest and most traditional method to prepare nanoenergetic composites, and preliminary findings have shown that these composites perform more effectively than their micro- or macro-sized counterparts in terms of energy release, ignition, and combustion. Powder mixing technology represents only the minimum capability of nanotechnology to boost the development of energetic material research, and it has intrinsic limitations, namely, random distribution of fuel and oxidizer particles, inevitable fuel pre-oxidation, and non-intimate contact between reactants. As an alternative, nanostructured energetic composites can be prepared through a delicately designed process. These composites outperform powder-mixed nanocomposites in numerous ways; therefore, we comprehensively discuss the preparation strategies adopted for nanostructured energetic composites and the research achievements thus far in this review. The latest ignition and reaction models are briefly introduced. Finally, the broad promising applications of nanostructured energetic composites are highlighted.

  15. Optics damage modeling and analysis at the National Ignition Facility

    Science.gov (United States)

    Liao, Z. M.; Raymond, B.; Gaylord, J.; Fallejo, R.; Bude, J.; Wegner, P.

    2014-10-01

    Comprehensive modeling of laser-induced damage in optics for the National Ignition Facility (NIF) has been performed on fused silica wedge focus lenses with a metric that compares the modeled damage performance to online inspections. The results indicate that damage models are successful in tracking the performance of the fused silica final optics when properly accounting for various optical finishes and mitigation processes. This validates the consistency of the damage models and allows us to further monitor and evaluate different system parameters that potentially can affect optics performance.

  16. Carbon Deflagration in Type Ia Supernova: I. Centrally Ignited Models

    CERN Document Server

    Ma, H; Malone, C M; Almgren, A; Bell, J B

    2013-01-01

    A leading model for Type Ia supernovae (SNe Ia) begins with a white dwarf near the Chandrasekhar mass that ignites a degenerate thermonuclear runaway close to its center and explodes. In a series of papers, we shall explore the consequences of ignition at several locations within such dwarfs. Here we assume central ignition, which has been explored before, however, the problem is worth revisiting, if only to validate those previous studies and to further elucidate the relevant physics for future work. A perturbed sphere of hot iron ash with a radius of ~100 km is initialized at the middle of the star. The subsequent explosion is followed in several simulations using a thickened flame model in which the flame speed is either fixed --- within the range expected from turbulent combustion --- or based on the local turbulent intensity. Global results, including the explosion energy and bulk nucleosynthesis (e.g. 56Ni of 0.48--0.56 $\\Msun$) turn out to be insensitive to this speed. In all completed runs, the energy...

  17. Railplug Ignition System for Enhanced Engine Performance and Reduced Maintenance

    Energy Technology Data Exchange (ETDEWEB)

    DK Ezekoye; Matt Hall; Ron Matthews

    2005-08-01

    This Final Technical Report discusses the progress that was made on the experimental and numerical tasks over the duration of this project. The primary objectives of the project were to (1) develop an improved understanding of the spark ignition process, and (2) develop the railplug as an improved ignitor for large bore stationary natural gas engines. We performed fundamental experiments on the physical processes occurring during spark ignition and used the results from these experiments to aid our development of the most complete model of the spark ignition process ever devised. The elements in this model include (1) the dynamic response of the ignition circuit, (2) a chemical kinetics mechanism that is suitable for the reactions that occur in the plasma, (3) conventional flame propagation kinetics, and (4) a multi-dimensional formulation so that bulk flow through the spark gap can be incorporated. This model (i.e., a Fortran code that can be used as a subroutine within an engine modeling code such as KIVA) can be obtained from Prof. Ron Matthews at rdmatt{at}mail.utexas.edu or Prof. DK Ezekoye at dezekoye{at}mail.utexas.edu. Fundamental experiments, engine experiments, and modeling tasks were used to help develop the railplug as a new ignitor for large bore natural gas engines. As the result of these studies, we developed a railplug that could extend the Lean Stability Limit (LSL) of an engine operating at full load on natural gas from {phi} = 0.59 for operation on spark plugs down to {phi} = 0.53 using railplugs with the same delivered energy (0.7 J). However, this delivered energy would rapidly wear out the spark plug. For a conventional delivered energy (<0.05 J), the LSL is {phi} = 0.63 for a spark plug. Further, using a permanent magnet to aid the plasma movement, the LSL was extended to {phi} = 0.54 for a railplug with a delivered energy of only 0.15 J/shot, a typical discharge energy for commercial capacitive discharge ignition systems. Here, it should be

  18. Ignition models and simulation of solid propellant of thermodynamic undersea vehicle

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jin-jun; QIAN Zhi-bo; YANG Jie; YAN Ping

    2007-01-01

    The starting characteristics of thermodynamic undersea vehicle systems are determined by the geometry, size and combustion area of solid propellants, which directly effect liquid propellant pipeline design. It is necessary to establish accurate burning models for solid propellants. Based on combustion models using powder tings and two different solid ignition grains, namely star-shaped ignition grains and stuffed ignition grains, a mathematic model of the ignition process of the propulsion system was built.With the help of Matlah, a series of calculations were made to determine the effects of different grains on ignition characteristics. The results show that stuffed ignition grain is best suited to be the ignition grain of a thermodynamic undersea vehicle system.

  19. Contribution to the study of an lpg jet in the combustion chamber of a spark-ignition engine; Contribution a l'etude d'un jet de gpl dans la chambre de combustion d'un moteur a allumage commande, pour differentes strategies d'injection

    Energy Technology Data Exchange (ETDEWEB)

    Duong Viet, D.

    2002-07-01

    It appears tempting to combine the less polluting combustion of LPG with the energy performances of a direct injection spark-ignition engine. To this aim the study of high pressure injection of a liquid LPG jet, directly inside the combustion chamber of an engine was performed in two ways: Experimental studies: one with fast cinematography and another with the method of Doppler phases in an one-cylinder 'transparent' engine for various conditions of injection and without combustion. They respectively deliver empirical laws for the jet development and some informations about size and speed of the droplets of LPG. A modeling of the jet could then be made on the basis of a turbulent and deviated jet the parameters of which could be adjusted using results of the preceding experimental study. (author)

  20. SciSpark: Highly Interactive and Scalable Model Evaluation and Climate Metrics

    Science.gov (United States)

    Wilson, B. D.; Palamuttam, R. S.; Mogrovejo, R. M.; Whitehall, K. D.; Mattmann, C. A.; Verma, R.; Waliser, D. E.; Lee, H.

    2015-12-01

    Remote sensing data and climate model output are multi-dimensional arrays of massive sizes locked away in heterogeneous file formats (HDF5/4, NetCDF 3/4) and metadata models (HDF-EOS, CF) making it difficult to perform multi-stage, iterative science processing since each stage requires writing and reading data to and from disk. We are developing a lightning fast Big Data technology called SciSpark based on ApacheTM Spark under a NASA AIST grant (PI Mattmann). Spark implements the map-reduce paradigm for parallel computing on a cluster, but emphasizes in-memory computation, "spilling" to disk only as needed, and so outperforms the disk-based ApacheTM Hadoop by 100x in memory and by 10x on disk. SciSpark will enable scalable model evaluation by executing large-scale comparisons of A-Train satellite observations to model grids on a cluster of 10 to 1000 compute nodes. This 2nd generation capability for NASA's Regional Climate Model Evaluation System (RCMES) will compute simple climate metrics at interactive speeds, and extend to quite sophisticated iterative algorithms such as machine-learning based clustering of temperature PDFs, and even graph-based algorithms for searching for Mesocale Convective Complexes. We have implemented a parallel data ingest capability in which the user specifies desired variables (arrays) as several time-sorted lists of URL's (i.e. using OPeNDAP model.nc?varname, or local files). The specified variables are partitioned by time/space and then each Spark node pulls its bundle of arrays into memory to begin a computation pipeline. We also investigated the performance of several N-dim. array libraries (scala breeze, java jblas & netlib-java, and ND4J). We are currently developing science codes using ND4J and studying memory behavior on the JVM. On the pyspark side, many of our science codes already use the numpy and SciPy ecosystems. The talk will cover: the architecture of SciSpark, the design of the scientific RDD (sRDD) data structure, our

  1. CFD modelling of solid propellant ignition

    OpenAIRE

    Lowe, C

    1996-01-01

    Solid propellant is the highly energetic fuel burnt in the combustion chamber of ballistic weapons. It is manufactured, for this purpose, in either granular or stick form. Internal ballistics describes the behavior within the combustion chamber throughout the ballistic cycle upto projectile exit from the muzzle of the gun barrel. Over the last twenty years this has been achieved by modelling the process using two-phase flow equations. The solid granules or sticks constitute ...

  2. Fonctionnement transitoire et controle de la richesse des moteurs à allumage commandé à injection multipoint Transient Operation and Air-Fuel Ratio Control of Spark-Ignition Port-Injected Engines

    Directory of Open Access Journals (Sweden)

    Le Moyne L.

    2006-12-01

    Full Text Available Sur les moteurs à allumage commandé à injection multipoint on observe des désadaptations de richesse lors de fonctionnement transitoire. Ces désadaptations sont dues au dépôt, sous forme de film liquide, du carburant injecté dans le collecteur. Elles peuvent être compensées par une gestion adéquate de la masse injectée. Ainsi, afin d'obtenir la masse de carburant qui maintient la richesse constante, nous avons développé un modèle bidimensionnel des écoulements dans le collecteur au cours du cycle moteur. Ce modèle décrit l'écoulement des gaz frais, des gouttes injectées, des gaz brûlés refoulés vers l'admission et du film sur les parois, sur le principe de la séparation des phases. Nous montrons que le modèle reproduit correctement le signal de richesse et comment il permet de supprimer les désadaptations. La mesure de richesse est faite à l'échappement avec une sonde à oxygène dont nous validons le fonctionnement en transitoire avec une corrélation à la pression maximale du cycle dans le cylindre. Air-fuel ratio excursions are observed on port-injected spark ignition engines during transients. This excursions result from the liquid fuel film deposited on intake port. They can be compensated by controlling the injected fuel mass. In order to have the amount of fuel that keeps air-fuel ratio constant, we have developed a 2D model of flows in the intake port during engine cycle. This separate phases model describes the flow of fresh gases, injected droplets, hot burned gases and film on port walls. We show that the model effectively predicts the equivalence ratio and how it allows to eliminate excursions. Equivalence ratio measures are made with an oxygen sensor which functioning is validated during transients by correlating it to maximal pressure during engine cycle.

  3. Advanced ignition and propulsion technology program

    Energy Technology Data Exchange (ETDEWEB)

    Oldenborg, R.; Early, J.; Lester, C.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Reliable engine re-ignition plays a crucial role in enabling commercial and military aircraft to fly safely at high altitudes. This project addressed research elements critical to the optimization of laser-based igniter. The effort initially involved a collaborative research and development agreement with B.F. Goodrich Aerospace and Laser Fare, Inc. The work involved integrated experiments with theoretical modeling to provide a basic understanding of the chemistry and physics controlling the laser-induced ignition of fuel aerosols produced by turbojet engine injectors. In addition, the authors defined advanced laser igniter configurations that minimize laser packaging size, weight, complexity and power consumption. These innovative ignition concepts were shown to reliably ignite jet fuel aerosols over a broad range of fuel/air mixture and a t fuel temperatures as low as -40 deg F. The demonstrated fuel ignition performance was highly superior to that obtained by the state-of-the-art, laser-spark ignition method utilizing comparable laser energy. The authors also developed a laser-based method that effectively removes optically opaque deposits of fuel hydrocarbon combustion residues from laser window surfaces. Seven patents have been either issued or are pending that resulted from the technology developments within this project.

  4. Experimental Investigation on the Ignition Delay Time of Plasma-Assisted Ignition

    Science.gov (United States)

    Xiao, Yang; Yu, Jin-Lu; He, Li-Ming; Jiang, Yong-Jian; Wu, Yong

    2016-09-01

    This paper investigates the ignition performances of plasma-assisted ignition in propane/air mixture. The results show that a shorter ignition delay time is obtained for the plasma ignition than the spark ignition and the average ignition delay time of plasma-assisted ignition can be reduced at least by 50%. The influence of air flow rate of combustor, the arc current and argon flow rate of plasma igniter on ignition delay time are also investigated. The ignition delay time of plasma-assisted ignition increases with increasing air flow rate in the combustor. By increasing the arc current, the plasma ignition will gain more ignition energy to ignite the mixture more easily. The influence of plasma ignition argon flow rates on the ignition delay time is quite minor.

  5. Modeling the ignition of a copper oxide aluminum thermite

    Science.gov (United States)

    Lee, Kibaek; Stewart, D. Scott; Clemenson, Michael; Glumac, Nick; Murzyn, Christopher

    2017-01-01

    An experimental "striker confinement" shock compression experiment was developed in the Glumac-group at the University of Illinois to study ignition and reaction in composite reactive materials. These include thermitic and intermetallic reactive powders. Sample of materials such as a thermite mixture of copper oxide and aluminum powders are initially compressed to about 80 percent full density. Two RP-80 detonators simultaneously push steel bars into the reactive material and the resulting compression causes shock compaction of the material and rapid heating. At that point one observes significant reaction and propagation of fronts. But the fronts are peculiar in that they are comprised of reactive events that can be traced to the reaction of the initially separated reactants of copper oxide and aluminum that react at their mutual interfaces, that nominally make copper liquid and aluminum oxide products. We discuss our model of the ignition of the copper oxide aluminum thermite in the context of the striker experiment and how a Gibbs formulation model [1], that includes multi-components for liquid and solid phases of aluminum, copper oxide, copper and aluminum oxide, can predict the events observed at the particle scale in the experiments.

  6. spark chamber

    CERN Multimedia

    A few cosmic rays pass through your body every second of every day, no matter where you are. Look at the spark chamber to your right – every flash is the track made by a cosmic ray from outer space. The spark chamber is filled with a special gas mixture. Cosmic rays knock electrons out of the atoms in the gas. These electrons accelerate towards high voltage metal strips layered throughout the chamber, creating sparks like little bolts of lightning.

  7. spark chamber

    CERN Multimedia

    A few cosmic rays pass through your body every second of every day, no matter where you are. Look at the spark chamber to your right – every flash is the track made by a cosmic ray from outer space. The spark chamber is filled with a special gas mixture. Cosmic rays knock electrons out of the atoms in the gas. These electrons accelerate towards high voltage metal strips layered throughout the chamber, creating sparks like little bolts of lightning.

  8. Optical Propagation Modeling for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Williams, W H; Auerbach, J M; Henesian, M A; Jancaitis, K S; Manes, K R; Mehta, N C; Orth, C D; Sacks, R A; Shaw, M J; Widmayer, C C

    2004-01-12

    Optical propagation modeling of the National Ignition Facility has been utilized extensively from conceptual design several years ago through to early operations today. In practice we routinely (for every shot) model beam propagation starting from the waveform generator through to the target. This includes the regenerative amplifier, the 4-pass rod amplifier, and the large slab amplifiers. Such models have been improved over time to include details such as distances between components, gain profiles in the laser slabs and rods, transient optical distortions due to the flashlamp heating of laser slabs, measured transmitted and reflected wavefronts for all large optics, the adaptive optic feedback loop, and the frequency converter. These calculations allow nearfield and farfield predictions in good agreement with measurements.

  9. Hydrodynamic modeling and simulations of shock ignition thresholds

    Directory of Open Access Journals (Sweden)

    Lafon M.

    2013-11-01

    Full Text Available The Shock Ignition (SI scheme [1] offers to reduce the laser requirements by relaxing the implosion phase to sub-ignition velocities and later adding an intense laser spike. Depending on laser energy, target characteristics and implosion velocity, high gains are expected [2,3]. Relevant intensities for scaled targets imploded in the velocity range from 150 to 400 km/s are defined at ignition thresholds. A range of moderate implosion velocities is specified to match safe implosions. These conditions for target design are then inferred for relevant NIF and LMJ shock-ignited targets.

  10. A Mathematical Model of the Single Aluminium Diboride Particle Ignition

    Directory of Open Access Journals (Sweden)

    D. A. Yagodnikov

    2014-01-01

    Full Text Available The paper presents a developed mathematical model of ignition of the single aluminum diboride particle as an aluminum-boron alloy in the oxidizing environment of a complicated chemical composition containing oxygen, water vapor, and carbon dioxide. The mathematical model is based on the theory of parallel chemical reactions proceeding on the appropriate parts of the particle surface occupied by each element in proportion to their molar share in the alloy. The paper considers a possibility to establish a thermodynamic balance between components over a particle surface in the gas phase. The composition of components is chosen as a result of thermodynamic calculation, namely В g , B2O3 g , BO, B2O2, BO2, Alg , AlO, Al2O, N2. The mathematical model is formed by a system of the differential equations of enthalpy balance, mass of aluminum diboride particle, and of formed oxides, which become isolated by initial and boundary conditions for temperature and size of particles, concentration of an oxidizer, and temperature of gas. The software package “AlB2“ is developed. It is a complete independent module written in Fortran algorithmic language, which together with a package of the subroutines “SPARKS” is used to calculate parameters of burning aluminum diboride particle by the Runge-Kutt method.For stoichiometry of chemical reactions of interaction between aluminum diboride and oxygen, a dynamics of changing temperature of a particle and thickness of an oxide film on its surface is calculated. It was admitted as initial conditions that the aluminum diboride particle radius was 100μ and the reference temperature of environment was 500 K, 1000 K, 2300 K, and 3000 K. Depending on this temperature the aluminum diboride particle temperature was calculated. Changing thickness of the oxide film on the particle surface at various initial gas temperatures characterizes its increase at the initial heating period of ~ 0,01 s and a gradual slowdown of the

  11. Multi-zone modelling of partially premixed low-temperature combustion in pilot-ignited natural-gas engines

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, S. R.; inivasan, K. K.

    2010-09-14

    Detailed results from a multi-zone phenomenological simulation of partially premixed advanced-injection low-pilot-ignited natural-gas low-temperature combustion are presented with a focus on early injection timings (the beginning of (pilot) injection (BOI)) and very small diesel quantities (2-3 per cent of total fuel energy). Combining several aspects of diesel and spark ignition engine combustion models, the closed-cycle simulation accounted for diesel autoignition, diesel spray combustion, and natural-gas combustion by premixed turbulent flame propagation. The cylinder contents were divided into an unburned zone, several pilot fuel zones (or 'packets') that modelled diesel evaporation and ignition, a flame zone for natural-gas combustion, and a burned zone. The simulation predicted the onset of ignition, cylinder pressures, and heat release rate profiles satisfactorily over a wide range of BOIs (20-60° before top dead centre (before TDC)) but especially well at early BOIs. Strong coupling was observed between pilot spray combustion in the packets and premixed turbulent combustion in the flame zone and, therefore, the number of ignition centres (packets) profoundly affected flame combustion. The highest local peak temperatures (greater than 2000 K) were observed in the packets, while the flame zone was much cooler (about 1650 K), indicating that pilot diesel spray combustion is probably the dominant source of engine-out emissions of nitrogen oxide (NOx). Further, the 60° before TDC BOI yielded the lowest average peak packet temperatures (about 1720 K) compared with the 20° before TDC BOI (about 2480 K) and 40° before TDC BOI (about 2700 K). These trends support experimental NOx trends, which showed the lowest NOx emissions for the 60°, 20°, and 40° before TDC BOIs in that order. Parametric studies showed that increasing the intake charge temperature, pilot quantity, and natural-gas equivalence ratio all led to

  12. Wildfire ignition-distribution modelling: a comparative study in the Huron-Manistee National Forest, Michigan, USA

    Science.gov (United States)

    Avi Bar Massada; Alexandra D. Syphard; Susan I. Stewart; Volker C. Radeloff

    2012-01-01

    Wildfire ignition distribution models are powerful tools for predicting the probability of ignitions across broad areas, and identifying their drivers. Several approaches have been used for ignition-distribution modelling, yet the performance of different model types has not been compared. This is unfortunate, given that conceptually similar species-distribution models...

  13. Review on performance of High energy ignition techniques

    Directory of Open Access Journals (Sweden)

    Jubin V Jose

    2015-12-01

    Full Text Available Ignition systems are the fundamental parts of spark ignition engines which determine the engine efficiency and pollutant emission. With the recent developments in engine technology significantly high spark energies are required. This paper reviews progress in alternative ignition systems that supply high energy sparks and more efficiently transfer energy to the gas mixture. The improvement in performance parameter of a spark plug such as net heat transfer rate, flame development time, exhaust gas emission rate are compared with conventional ignition systems. This paper also tries to identify critical research gap and also the advantages and limitations of advanced systems with reference to the advanced researches reported in this area.

  14. Mean Value Modelling of Turbocharged SI Engines

    DEFF Research Database (Denmark)

    Müller, Martin; Hendricks, Elbert; Sorenson, Spencer C.

    1998-01-01

    The development of a computer simulation to predict the performance of a turbocharged spark ignition engine during transient operation. New models have been developed for the turbocharged and the intercooling system. An adiabatic model for the intake manifold is presented....

  15. Numerical contribution to the characterisation and predictive calculation of mixture formation and combustion in a jet-guided direct-injected spark ignition engine[Dissertation 14937]; Numerischer Beitrag zur Charakterisierung und Vorausberechnung der Gemischbildung und Verbrennung in einem direkteingespritzten, strahlgefuehrten Ottomotor

    Energy Technology Data Exchange (ETDEWEB)

    Koch, T.

    2000-07-01

    The present thesis deals with the thermodynamic, physical and chemical processes inside a jet-guided direct injected spark ignition engine. The main focus on the investigations has been set on the phenomena of mixture formation and combustion. The objective of this work was the development of a physically based, fast model to predict the heat release and pressure evolution. Therefore, numerous fundamental investigations were carried out prior to defining the basis of the phenomenological approach. The dominating influence of the fuel injection has been investigated with extensive three-dimensional simulations of the two-phase flow for quiescent laboratory conditions subsequently experimentally validated as well as for the engine applications. Spray penetration, the evaporation rate and the turbulence influence of the hollow-cone spray have been of particular importance. Comprehensive mainly optically based experiments have also been performed in parallel within the scope of a second thesis. The synergetic combination of numerical with experimental investigations yielded insights into key phenomena and led to a detailed understanding of the relevant combustion-related process. The phenomenological modeling of the determining process of injection, fuel evaporation, mixture formation, ignition, heat release and NO formation has been performed by concentrating on the most significant individual physical phenomena. Thereby the focus has been on the formulation of the combustion by a superposition of a premixed and mixing controlled approach. The newly developed model has been tested for numerous operating conditions in stratified as well as homogenous charge. Additionally, multidimensional operating maps have been simulated which serve as a basis for complete vehicle-cycle computations. (author)

  16. Evaluation of Butanol–Gasoline Blends in a Port Fuel-injection, Spark-Ignition Engine Évaluation de mélange butanol-essence dans un moteur à allumage commandé à injection indirecte

    Directory of Open Access Journals (Sweden)

    Dernotte J.

    2009-11-01

    Full Text Available This paper assesses different butanol–gasoline blends used in a port fuel-injection, spark-ignition engine to quantify the influence of butanol addition on the emission of unburned hydrocarbons, carbon monoxide, and nitrogen oxide. Furthermore, in-cylinder pressure was measured to quantify combustion stability and to compare the ignition delay and fully developed turbulent combustion phases as given by 0%–10% and 10%–90% Mass Fraction Burned (MFB. The main findings are: 1 a 40% butanol/60% gasoline blend by volume (B40 minimizes HC emissions; 2 no significant change in NOx emissions were observed, with the exception of the 80% butanol/20% gasoline blend; 3 the addition of butanol improves combustion stability as measured by the COV of IMEP; 4 butanol added to gasoline reduces ignition delay (0%–10% MFB; and 5 the specific fuel consumption of B40 blend is within 10% of that of pure gasoline for stoichiometric mixture. Cet article évalue le potentiel de l’utilisation de différents mélanges butanolessence dans un moteur à allumage commandé à injection indirecte afin de quantifier l’influence de l’ajout de butanol sur les émissions des hydrocarbures imbrûlés (HC, le monoxyde de carbone (CO et les oxydes d’azote (NOx. De plus, l’influence sur la stabilité de combustion, le délai d’inflammation et sur la durée de la phase de combustion turbulente développée y sont également présentés. Les principaux résultats: 1 un mélange de 40% butanol et 60% essence (B40 par volume diminue les émissions de HC; 2 aucun effet significatif sur les émissions de NOx n’a été observé à l’exception du mélange 80% butanol/20% essence; 3 l’ajout de butanol améliore la stabilité de combustion ; 4 l’ajout de butanol réduit le délai d’inflammation, quantifié par la durée pour consommer 10% de masse de gaz frais; et 5 la consommation spécifique de carburant pour un mélange stoechiométrique de B40 est 10% sup

  17. SparkJet Efficiency

    Science.gov (United States)

    Golbabaei-Asl, Mona; Knight, Doyle; Anderson, Kellie; Wilkinson, Stephen

    2013-01-01

    A novel method for determining the thermal efficiency of the SparkJet is proposed. A SparkJet is attached to the end of a pendulum. The motion of the pendulum subsequent to a single spark discharge is measured using a laser displacement sensor. The measured displacement vs time is compared with the predictions of a theoretical perfect gas model to estimate the fraction of the spark discharge energy which results in heating the gas (i.e., increasing the translational-rotational temperature). The results from multiple runs for different capacitances of c = 3, 5, 10, 20, and 40 micro-F show that the thermal efficiency decreases with higher capacitive discharges.

  18. Numerical Modeling of the Atmospheric-Pressure Helium Plasma Formed During Spark-to-Glow Discharge Transition

    Science.gov (United States)

    Demkin, V. P.; Melnichuk, S. V.

    2017-06-01

    Results of numerical experiment on modeling of the atmospheric-pressure plasma formed during the spark-to-glow discharge transition in helium in low-current non-stationary plasmatron are presented. The numerical experiment is performed using the developed 2D physical and mathematical plasma model in the drift-diffusion approximation. Results of numerical calculation of the dynamics of discharge evolution are confirmed by the experimental data on the atmospheric-pressure plasma dynamics formed in the plasmatron during the spark-to-glow discharge transition. It is demonstrated that with preset initial conditions characteristic for spark breakdown, further discharge evolution leads to the formation of the near-cathode zone of the potential drop and the pulsed behavior of the electric current of the discharge. After the current pulse, the discharge transforms into the quasi-stationary mode with parameters characteristic for the glow discharge with monotonically increasing electric current and transverse dimensions of the plasma column.

  19. Estimation of the ignition probability due to mechanically generated impact sparks in explosive gas/air-mixtures. Examinations of the materials combination: steel/steel; Ermittlung der Zuendwahrscheinlichkeit mechanisch erzeugter Schlagfunken in explosionsfaehigen Brenngas/Luft-Gemischen. Untersuchung der Werkstoffkombination Stahl/Stahl

    Energy Technology Data Exchange (ETDEWEB)

    Grunewald, T.; Graetz, R.

    2007-09-29

    Equipment intended for use in potentially explosive atmospheres must meet the requirements of the European directive 94/9/EC. The declaration of conformity of the manufacturer testifies that they meet the requirements. The conformity assessment is based on the risk (ignition) assessment which identifies and estimates the ignition sources. The European standards in the area of the directive 94/9/EC (like EN 1127-1, EN 13463-1) describe 13 possible ignition sources. Mechanically generated sparks are one of them. Statements to the ignition effectiveness and especially the ignition probability in case of mechanically generated sparks for a given kinetic impact energy and given explosive gas/air-mixtures are not possible. An extensive literature looking confirms this state. This was and is a problem in making and revising standards. Simple ferritic steel is a common material for the construction of equipment also for non electrical applications intended for use in potentially explosive atmospheres for chemical and mechanical engineering and manufacturing technology. Therefore it was the objective of this study to get some statistical ignition probabilities depending on the kinetic impact energy and the minimum ignition energy of the explosive gas/air-mixture. This study was made with impact testing machines of BAM (Federal Institute of Materials Research and Testing) at three kinetic impact energies. The following results were obtained for all the reference gas/air-mixtures of the IEC-explosion groups (I methane, IIA propane, IIB ethylene, IIC acetylene, hydrogen): 1. It was not possible to generate ignitable mechanically sparks for kinetic impact energies below 3 Nm for the test conditions in this study respectively the impact kinetics and impact geometry of the impact machines. 2. Single mechanically generated particles were able to be a dangerous ignition source through oxidation process at kinetic impact energies of 10 Nm. Furthermore the tests have shown that the

  20. Development status of the ignition system for Vinci

    NARCIS (Netherlands)

    Frenken, G.; Vermeulen, E.; Bouquet, F.; Sanders, H.M.

    2002-01-01

    The development status of ignition system for the new cryogenic upper stage engine Vinci is presented. The concept differs from existing upper stage ignition systems as its functioning is engine independent. The system consists of a spark torch igniter, a highpressure igniter feed system and an exci

  1. Mathematical model for prediction of pyrolysis and ignition of wood under external heat flux

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The pyrolysis and ignition of combustible materials is an important aspect of the processes taking place in an unwanted fire. A prediction model presented in this paper is to study pyrolysis and ignition time of wood under external heat flux. The solution of the model provides the temperature at each point of the solid and the local solid conversion. And the time to ignition of the wood is predicted with the solution of surface temperature. In general, a good agreement between experimental and theoretical results is obtained.

  2. Experimental studies on the group ignition of a cloud of coal particles: Volume 2, Pyrolysis and ignition modeling. Final report, August 15, 1988--October 15, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Annamalai, K.; Ryan, W.

    1992-01-01

    The primary objectives of this work are to formulate a model to simulate transient coal pyrolysis, ignition, and combustion of a cloud of coal particles and to compare results of the program with those reported in the literature elsewhere.

  3. Ignition and Growth Reactive Flow Model for IMX-101

    Energy Technology Data Exchange (ETDEWEB)

    Tarver, Craig M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-02-19

    A set of Ignition and Growth (I&G) reactive flow model parameters is developed for the explosive IMX-101 containing DNAN, NQ, and NTO using the available shock initiation and detonation wave propagation experimental data. The unreacted equation of state for IMX-101 is based on experimental data from gas gun experiments by Furnish et al. and is similar to that of TNT. The product equation of state for IMX-101 is based on CHEETAH chemical equilibrium calculations and cylinder test experimental data. The IMX-101 reaction rate parameters are developed using hydrodynamic reactive flow simulations of several shock initiation and detonation experiments. One set of I&G parameters does a good job of reproducing both shock initiation and detonation experimental data. This is due to the fact that IMX-101 reacts over a relatively small pressure range from about 7 GPa to 20 GPa (C-J pressure). Advanced experiments using embedded gauges and/or laser interferometry could lead to better parameters.

  4. The effect of kerosene injection on ignition probability of local ignition in a scramjet combustor

    Science.gov (United States)

    Bao, Heng; Zhou, Jin; Pan, Yu

    2017-03-01

    The spark ignition of kerosene is investigated in a scramjet combustor with a flight condition of Ma 4, 17 km. Based plentiful of experimental data, the ignition probabilities of the local ignition have been acquired for different injection setups. The ignition probability distributions show that the injection pressure and injection location have a distinct effect on spark ignition. The injection pressure has both upper and lower limit for local ignition. Generally, the larger mass flow rate will reduce the ignition probability. The ignition position also affects the ignition near the lower pressure limit. The reason is supposed to be the cavity swallow effect on upstream jet spray near the leading edge, which will make the cavity fuel rich. The corner recirculation zone near the front wall of the cavity plays a significant role in the stabilization of local flame.

  5. Multi-dimensional modeling of the application of catalytic combustion to homogeneous charge compression ignition engine

    Science.gov (United States)

    Zeng, Wen; Xie, Maozhao

    2006-12-01

    The detailed surface reaction mechanism of methane on rhodium catalyst was analyzed. Comparisons between numerical simulation and experiments showed a basic agreement. The combustion process of homogeneous charge compression ignition (HCCI) engine whose piston surface has been coated with catalyst (rhodium and platinum) was numerically investigated. A multi-dimensional model with detailed chemical kinetics was built. The effects of catalytic combustion on the ignition timing, the temperature and CO concentration fields, and HC, CO and NOx emissions of the HCCI engine were discussed. The results showed the ignition timing of the HCCI engine was advanced and the emissions of HC and CO were decreased by the catalysis.

  6. DEPENDENCE OF QUALITATIVE BEHAVIOR OF THE NUMERICAL SOLUTIONS ON THE IGNITION TEMPERATURE FOR A COMBUSTION MODEL

    Institute of Scientific and Technical Information of China (English)

    Xin-ting Zhang; Lung-an Ying

    2005-01-01

    We study the dependence of qualitative behavior of the numerical solutions (obtained by a projective and upwind finite difference scheme) on the ignition temperature for a combustion model problem with general initial condition. Convergence to weak solution is proved under the Courant-Friedrichs-Lewy condition. Some condition on the ignition temperature is given to guarantee the solution containing a strong detonation wave or a weak detonation wave. Finally, we give some numerical examples which show that a strong detonation wave can be transformed to a weak detonation wave under some well-chosen ignition temperature.

  7. A model for the prediction of the thermal degradation and ignition of wood under constant and variable heat flux

    Energy Technology Data Exchange (ETDEWEB)

    Bilbao, Rafael; Mastral, Jose F.; Ceamanos, Jesus; Aldea, Maria E.; Betran, Monica [Department of Chemical and Environmental Engineering, Faculty of Sciences,University of Zaragoza, Pedro Cerbuna 12, Zaragoza (Spain); Lana, Jose A. [Direction of Technology and Environment, Enagas-Gas Natural, Crta. Madrid, Zaragoza (Spain)

    2002-01-01

    The ignition of combustible materials is an important aspect of the processes taking place in an unwanted fire. In this work, an experimental and theoretical study of the ignition process of wood has been carried out. Experiments of both spontaneous and piloted ignition have been performed. Constant and decreasing variable heat fluxes have been tested. A mathematical model has been used to predict the time to ignition of wood for the different operating conditions used. The solution of the model provides the temperature at each point of the solid, the local solid conversion and the time to ignition of the material. In general, a good agreement between experimental and theoretical results is obtained.

  8. Influence of Injector Location on Part-Load Performance Characteristics of Natural Gas Direct-Injection in a Spark Ignition Engine

    Energy Technology Data Exchange (ETDEWEB)

    Sevik, James [Argonne National Lab. (ANL), Argonne, IL (United States); Pamminger, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Wallner, Thomas [Argonne National Lab. (ANL), Argonne, IL (United States); Scarcelli, Riccardo [Argonne National Lab. (ANL), Argonne, IL (United States); Boyer, Brad [Ford Motor Co., Detroit, MI (United States); Wooldridge, Steven [Ford Motor Co., Detroit, MI (United States); Hall, Carrie [Illinois Inst. of Technology, Chicago, IL (United States); Miers, Scott [Michigan Technological Univ., Houghton, MI (United States)

    2016-04-05

    performance in terms of combustion metrics and efficiencies. For both systems, part-load dilution tolerance is affected by the injection timing, due to the induced turbulence from the gaseous injection event. CFD simulation results have shown that there is a fundamental difference in how the two injection locations affect the mixture formation process. Delayed injection timing increases the turbulence level in the cylinder at the time of the spark, but reduces the available time for proper mixing. Side injection delivers a gaseous jet that interacts more effectively with the intake induced flow field, and this improves the engine performance in terms of efficiency.

  9. Natural gas and blends oxidation and ignition: Experiments and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Y.; Dagaut, P.; Cathonnet, M.; Boettner, J.C. [CNRS, Orleans (France); Bachman, J.S.; Carlier, P. [Gaz de France, La Plaine-Saint-Denis (France)

    1994-12-31

    The kinetics of the oxidation of natural gas and blends (CH{sub 4}/C{sub 2}H{sub 6}, CH{sub 4}/C{sub 3}H{sub 8}, CH{sub 4}/C{sub 2}H{sub 6}/C{sub 3}H{sub 8}) has been studied in a jet-stirred reactor (800 {<=} T/K {<=} 1240, 1 {<=} P/atm {<=} 10, 0.1 {<=} equivalence ratio {<=} 1.5). The concentration profiles of reactants, intermediates, and products measured in a jet-stirred reactor (JSR) have been used to validate a detailed kinetic reaction mechanism. Literature ignition delay times measured in shock tube have also been modeled. A generally good agreement between the data and the model is found. The same mechanism has also been used to successfully represent the oxidation of methane, ethyne, ethene, ethane, propene, propane, n-butane, and 1-butene in various conditions including JSR, shock tube, and flame. The present study clearly shows the importance of trace hydrocarbons in the oxidation of methane. The computations indicate that the oxidation of methane is initiated by its reaction with O{sub 2} when no other hydrocarbon is present. In natural gas and blends, higher hydrocarbons react before methane, leading to the formation of OH, H, and O radicals, which in turn initiate methane oxidation. This work demonstrates that methane cannot be used safely to represent the kinetics of natural gas combustion. However, simple blends like methane-propane or methane-ethane-propane could be used.

  10. Knock Prediction Using a Simple Model for Ignition Delay

    KAUST Repository

    Kalghatgi, Gautam

    2016-04-05

    An earlier paper has shown the ability to predict the phasing of knock onset in a gasoline PFI engine using a simple ignition delay equation for an appropriate surrogate fuel made up of toluene and PRF (TPRF). The applicability of this approach is confirmed in this paper in a different engine using five different fuels of differing RON, sensitivity, and composition - including ethanol blends. An Arrhenius type equation with a pressure correction for ignition delay can be found from interpolation of previously published data for any gasoline if its RON and sensitivity are known. Then, if the pressure and temperature in the unburned gas can be estimated or measured, the Livengood-Wu integral can be estimated as a function of crank angle to predict the occurrence of knock. Experiments in a single cylinder DISI engine over a wide operating range confirm that this simple approach can predict knock very accurately. The data presented should enable engineers to study knock or other auto-ignition phenomena e.g. in premixed compression ignition (PCI) engines without explicit chemical kinetic calculations. © Copyright 2016 SAE International.

  11. Observations and Modeling of Long Negative Laboratory Discharges: Identifying the Physics Important to an Electrical Spark in Air

    Energy Technology Data Exchange (ETDEWEB)

    Biagi, C J; Uman, M A

    2011-12-13

    There are relatively few reports in the literature focusing on negative laboratory leaders. Most of the reports focus exclusively on the simpler positive laboratory leader that is more commonly encountered in high voltage engineering [Gorin et al., 1976; Les Renardieres Group, 1977; Gallimberti, 1979; Domens et al., 1994; Bazelyan and Raizer 1998]. The physics of the long, negative leader and its positive counterpart are similar; the two differ primarily in their extension mechanisms [Bazelyan and Raizer, 1998]. Long negative sparks extend primarily by an intermittent process termed a 'step' that requires the development of secondary leader channels separated in space from the primary leader channel. Long positive sparks typically extend continuously, although, under proper conditions, their extension can be temporarily halted and begun again, and this is sometimes viewed as a stepping process. However, it is emphasized that the nature of positive leader stepping is not like that of negative leader stepping. There are several key observational studies of the propagation of long, negative-polarity laboratory sparks in air that have aided in the understanding of the stepping mechanisms exhibited by such sparks [e.g., Gorin et al., 1976; Les Renardieres Group, 1981; Ortega et al., 1994; Reess et al., 1995; Bazelyan and Raizer, 1998; Gallimberti et al., 2002]. These reports are reviewed below in Section 2, with emphasis placed on the stepping mechanism (the space stem, pilot, and space leader). Then, in Section 3, reports pertaining to modeling of long negative leaders are summarized.

  12. Experiments and computational modeling of pulverized-coal ignition. Semiannual report, Apr 1, 1998--Sep 30, 1998

    Energy Technology Data Exchange (ETDEWEB)

    John C. Chen; Samuel Owusu-Ofori

    1998-10-31

    Under typical conditions of pulverized-coal combustion, which is characterized by fine particles heated at very high rates, there is currently a lack of certainty regarding the ignition mechanism of bituminous and lower rank coals. It is unclear whether ignition occurs first at the particle-oxygen interface (heterogeneous ignition) or if it occurs in the gas phase due to ignition of the devolatilization products (homogeneous ignition). Furthermore, there have been no previous studies aimed at determining the dependence of the ignition mechanism on variations in experimental conditions, such as particle size, oxygen concentration, and heating rate. Finally, there is a need to improve current mathematical models of ignition to realistically and accurately depict the particle-to-particle variations that exist within a coal sample. Such a model is needed to extract useful reaction parameters from ignition studies, and to interpret ignition data in a more meaningful way. The authors propose to examine fundamental aspects of coal ignition through (1) experiments to determine the ignition mechanism of various coals by direct observation, and (2) modeling of the ignition process to derive rate constants and to provide a more insightful interpretation of data from ignition experiments. They propose to use a novel laser-based ignition experiment to achieve their objectives. The heating source will be a pulsed, carbon dioxide laser in which both the pulse energy and pulse duration are independently variable, allowing for a wide range of heating rates and particle temperatures--both of which are decoupled from each other and from the particle size. This level of control over the experimental conditions is truly novel in ignition and combustion experiments. Laser-ignition experiments also offer the distinct advantage of easy optical access to the particles because of the absence of a furnace or radiating walls, and thus permit direct observation and particle temperature

  13. Exergetic Evaluation of Speed and Load Effects in Spark Ignition Engines Évaluation exergétique des effets de la vitesse et de la charge dans les moteurs àallumage par étincelle

    Directory of Open Access Journals (Sweden)

    Sezer I.

    2012-08-01

    Full Text Available This study investigates the effects of various operating conditions in spark ignition engines via an exergy analysis. A thermodynamic cycle model including compression, combustion and expansion processes was used for investigation. Induction and exhaust processes were computed with a simple approximation method. The principles of the second law were applied to the cycle model to perform the exergy analysis. Exergetic variables, i.e., the exergy transfers with heat and work, irreversibilities, thermomechanical exergy, fuel chemical exergy and total exergy were calculated in the exergy analysis. Variation of the exergetic parameters and the distribution of them into the fuel exergy were determined for various operating conditions, i.e., engine speed and load. The first and second law efficiencies and specific fuel consumption were also computed to reveal the optimum operating conditions. The results show that the exergy transfer with heat decreases and the exergy transfer with exhaust gases increases with increasing engine speed. Engine speed of 3 000 rpm gives the maximum exergy transfer as work, the minimum irreversibility and the best efficiency and fuel consumption. Exergy transfers with heat, work and exhaust and irreversibilities increase with increasing engine load. Additionally, the first and second law efficiencies increase and fuel consumption decreases with increasing engine load, so a high engine load gives the best efficiency and fuel consumption. Cette étude examine les effets des différentes conditions de fonctionnement de moteurs à allumage commandé via une analyse exergétique. Un modèle de cycle thermodynamique comprenant les processus de compression, combustion et détente a été utilisé. Les processus d’admission et d’échappement sont modélisés à l’aide d’une méthode simple d’approximation. Les principes de la deuxième loi de la thermodynamique ont été appliqués au modèle de cycle pour effectuer l

  14. Performance of a diesel engine transformed to spark ignition using natural gas; Desempenho de um motor diesel convertido para utilizacao de gas natural como combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, Ricardo H.R. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LEDAV/COPPE/UFRJ), RJ (Brazil). Lab. de Ensaios Dinamicos e Analise de Vibracao; Belchior, Carlos R.P. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LMT/COPPE/UFRJ), RJ (Brazil). Lab. de Maquinas Termicas; Sodre, Jose Ricardo [Pontificia Universidade Catolica de Minas Gerais (PUC/Minas), MG (Brazil)

    2012-07-01

    A zero-dimensional thermodynamic model for a diesel engine converted for dedicated use of natural gas was developed in this work. The computational model covers from the time of closing the inlet valve to the time of opening the exhaust valve and it was divided into three stages (compression, combustion and expansion). A model based on the first law of thermodynamics for closed cycle has been developed to study the performance of the engine. The combustion process was modeled using the equation of Wiebe. It was taken into consideration the convective heat transfer through the walls of the cylinder and the heat transfer coefficient was calculated by the Eichelberg correlation. It was also considered that the thermodynamic properties vary with temperature. To represent the gas mixture behavior inside the cylinder two approaches (Ideal Gas Equation and Van Der Waals's Real Gas Equation) were used and results compared. The computational model was validated with experimental tests. (author)

  15. Dynamics of shock induced ignition in Fickett's model with chain-branching kinetics: influence of $\\chi$

    CERN Document Server

    Tang, Justin

    2012-01-01

    The problem of shock induced ignition by a piston is addressed in the framework of Fickett's model for reactive compressible flows, i.e., the reactive form of Burgers' equation. An induction-reaction two-step chain-branching model is used to study the coupling between the energy release and the compressible hydrodynamics occurring during the shock ignition transient leading to a detonation. Owing to the model's simplicity, the ignition and acceleration mechanism is explained using the two families of characteristics admitted by the model. The energy release along the particle paths provides the amplification of forward-travelling pressure waves. These waves pre-compress the medium in the induction layer ahead of the reaction zone, therefore changing the induction delays of successive particles. The variation of the induction delay provides the modulation of the amplification of the forward travelling pressure waves by controlling the residence time of the pressure waves in the reaction zone. A closed form ana...

  16. Report from the Integrated Modeling Panel at the Workshop on the Science of Ignition on NIF

    Energy Technology Data Exchange (ETDEWEB)

    Marinak, M; Lamb, D

    2012-07-03

    This section deals with multiphysics radiation hydrodynamics codes used to design and simulate targets in the ignition campaign. These topics encompass all the physical processes they model, and include consideration of any approximations necessary due to finite computer resources. The section focuses on what developments would have the highest impact on reducing uncertainties in modeling most relevant to experimental observations. It considers how the ICF codes should be employed in the ignition campaign. This includes a consideration of how the experiments can be best structured to test the physical models the codes employ.

  17. Gasoline surrogate modeling of gasoline ignition in a rapid compression machine and comparison to experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mehl, M; Kukkadapu, G; Kumar, K; Sarathy, S M; Pitz, W J; Sung, S J

    2011-09-15

    The use of gasoline in homogeneous charge compression ignition engines (HCCI) and in duel fuel diesel - gasoline engines, has increased the need to understand its compression ignition processes under engine-like conditions. These processes need to be studied under well-controlled conditions in order to quantify low temperature heat release and to provide fundamental validation data for chemical kinetic models. With this in mind, an experimental campaign has been undertaken in a rapid compression machine (RCM) to measure the ignition of gasoline mixtures over a wide range of compression temperatures and for different compression pressures. By measuring the pressure history during ignition, information on the first stage ignition (when observed) and second stage ignition are captured along with information on the phasing of the heat release. Heat release processes during ignition are important because gasoline is known to exhibit low temperature heat release, intermediate temperature heat release and high temperature heat release. In an HCCI engine, the occurrence of low-temperature and intermediate-temperature heat release can be exploited to obtain higher load operation and has become a topic of much interest for engine researchers. Consequently, it is important to understand these processes under well-controlled conditions. A four-component gasoline surrogate model (including n-heptane, iso-octane, toluene, and 2-pentene) has been developed to simulate real gasolines. An appropriate surrogate mixture of the four components has been developed to simulate the specific gasoline used in the RCM experiments. This chemical kinetic surrogate model was then used to simulate the RCM experimental results for real gasoline. The experimental and modeling results covered ultra-lean to stoichiometric mixtures, compressed temperatures of 640-950 K, and compression pressures of 20 and 40 bar. The agreement between the experiments and model is encouraging in terms of first

  18. Modeling and evaluation of the influence of micro-EDM sparking state settings on the tool electrode wear behavior

    DEFF Research Database (Denmark)

    Puthumana, Govindan

    2017-01-01

    Micromachining technologies are now being employed in various industries for generation of precise features on engineering components. Among these processes, micro electrical discharge machining is a 'non-contact' machining technology suitable for material removal from electrically conductive...... materials characterized by considerable wear ofthe tool used for material removal. This paper presents an investigation involving modeling and estimation of the effect of settings for generation of discharges in stable conditions of micro-EDM on the phenomenon of tool electrode wear. A stable sparking...... condition during the process is achieved with varying voltage (V), capacitance (C), threshold (T), and discharge frequency (f). The tool electrode wear model has revealed that the energy of the sparks interacting with the tool surfaces control the phenomenon through the settings of capacitance followed...

  19. Implosion of an underwater spark-generated bubble and acoustic energy evaluation using the Rayleigh model.

    Science.gov (United States)

    Buogo, Silvano; Cannelli, Giovanni B

    2002-06-01

    The growth, collapse, and rebound of a vapor bubble generated by an underwater spark is studied by means of high-speed cinematography, simultaneously acquiring the emitted acoustic signature. Video recordings show that the growth and collapse phases are nearly symmetrical during the first two or three cycles, the bubble shape being approximately spherical. After 2-3 cycles the bubble behavior changes from a collapsing/rebounding regime with sound-emitting implosions to a pulsating regime with no implosions. The motion of the bubble wall during the first collapses was found to be consistent with the Rayleigh model of a cavity in an incompressible liquid, with the inclusion of a vapor pressure term at constant temperature within each bubble cycle. An estimate of the pressure inside the bubble is obtained measuring the collapse time and maximum radius, and the amount of energy converted into acoustical energy upon each implosion is deduced. The resulting value of acoustic efficiency was found to be in agreement with measurements based on the emitted acoustic pulse.

  20. Computer aided engineering in exhaust aftertreatment systems design. Pt. 1. Spark ignition engine; Computergestuetzter Entwurf von Abgas-Nachbehandlungskonzepten. T. 1. Ottomotor

    Energy Technology Data Exchange (ETDEWEB)

    Stamatelos, A.M.; Koltsakis, G.C.; Kandylas, I.P. [Aristotelian Univ. of Thessaloniki (Greece)

    1999-02-01

    At the Aristotle University Thessaloniki, Greece, an integrated Computer Aided Engineering (CAE) methodology assisting the design of SI-engine exhaust aftertreatment systems employing the following computational tools was developed: A computer code which models transient exhaust system heat transfer, a tuneable computer code which models the transient operation of a three-way catalytic converter, a database containing chemical kinetics data for a variety of catalyst formulations, and a methodology for ageing assessment calculations. Application of the CAE methodology, which aids the exhaust aftertreatment system design engineer to meet the upcoming, increasingly stringent emission standards, is high-lighted by referring to a number of representative case studies. (orig.) [Deutsch] An der Aristoteles-Universitaet Thessaloniki, Griechenland, wurde eine computergestuetzte Methode (CAE) entwickelt, die den Entwurf und die Konstruktion von Abgasnachbehandlungskonzepten unterstuetzt. Die Methode setzt auf die folgenden Rechenmodelle und Datenbanken: Ein Rechenmodell zur Berechnung des Waermeuebergangs in Motorabgassystemen, ein Rechenmodell zur Abschaetzung des Katalysatorgegendrucks, eine Datenbank mit den chemischen Kinetikdaten fuer die verschiedenen Typen von Dreiwegekatalysatoren und eine computergestuetzte Prozedur zur Abschaetzung des Alterungsverhaltens von Dreiwegekatalysatoren. Integrierte CAE-Methoden koennen beim Entwurf von modernen Abgasnachbehandlungssystemen angewandt werden, um die Entwicklungszeit und -kosten betraechtlich zu reduzieren. (orig.)

  1. The new small spark ignited engine family. Ranging from the naturally aspirated three-cylinder to the boosted four-cylinder; Die neue kleine Ottomotorenfamilie von General Motors. Vom freisaugenden Dreizylinder bis zum aufgeladenen Vierzylinder

    Energy Technology Data Exchange (ETDEWEB)

    Boehler, G.; Buhr, R.; Reinheimer, G. [Adam Opel GmbH, Ruesselsheim (Germany)

    2010-07-01

    The new small spark ignited engine family of GM (internal nomination family 0) with displacements from 1.0 to 1.4ltrs. covers 25% of the Opel vehicle volume. To comply with numerous requirements in respect of fuel economy, exhaust emission reductions, demanded efficient downsizing, and alternative propulsion concepts, Opel has made a fundamental revision of its Fam 0 engine family and added new engine variants to its portfolio. Above this a good compromise between technology available, and justifiable cost of manufacture had to be made without infringing the overriding objectives in this cost sensitive vehicle segment. The third generation of this engine family is consequent refinement of the second generation three- and four-cylinder engines already proven millions of times. The program is upgraded by a newly developed 1.4 ltr. turbo engine, a modular derivative of the naturally aspirated engines, which was realized in the form of a downsizing/ downspeeding concept, resulting in fuel economy improvements of up to 12 %. In the new Astra the exhaust emissions of the turbo engine are as low as 139 g CO{sub 2}/km. The four-cylinder engines feature continuously variable cam phasers on both intake and exhaust side, a volume flow-controlled oil pump, and an electrically controlled thermostat. For the naturally aspirated engines the port de-activation system introduced with the second generation was further developed and matched with the requirements of internal exhaust gas return. Increased acoustic requirements were accommodated by targeted structural measures, the use of torsional vibration dampers for all engines, and further optimization of charge cycles and combustion. A modified 1.4 ltr. naturally aspirated engine will be employed late this year in the trend-setting alternative propulsion concept of the extended range Chevrolet Volt vehicle, and at a later date in the Opel Ampera. The engines are manufactured in Aspern on the outskirts of Vienna. In late 2010 an

  2. Components of Particle Emissions from Light-Duty Spark-Ignition Vehicles with Varying Aromatic Content and Octane Rating in Gasoline.

    Science.gov (United States)

    Short, Daniel Z; Vu, Diep; Durbin, Thomas D; Karavalakis, Georgios; Asa-Awuku, Akua

    2015-09-01

    Typical gasoline consists of varying concentrations of aromatic hydrocarbons and octane ratings. However, their impacts on particulate matter (PM) such as black carbon (BC) and water-soluble and insoluble particle compositions are not well-defined. This study tests seven 2012 model year vehicles, which include one port fuel injection (PFI) configured hybrid vehicle, one PFI vehicle, and six gasoline direct injection (GDI) vehicles. Each vehicle was driven on the Unified transient testing cycle (UC) using four different fuels. Three fuels had a constant octane rating of 87 with varied aromatic concentrations at 15%, 25%, and 35%. A fourth fuel with higher octane rating, 91, contained 35% aromatics. BC, PM mass, surface tension, and water-soluble organic mass (WSOM) fractions were measured. The water-insoluble mass (WIM) fraction of the vehicle emissions was estimated. Increasing fuel aromatic content increases BC emission factors (EFs) of transient cycles. BC concentrations were higher for the GDI vehicles than the PFI and hybrid vehicles, suggesting a potential climate impact for increased GDI vehicle production. Vehicle steady-state testing showed that the hygroscopicity of PM emissions at high speeds (70 mph; κ > 1) are much larger than emissions at low speeds (30 mph; κ emissions. Both aromatic content and vehicle speed increase the amount of hygroscopic material found in particle emissions.

  3. Why not use niche modelling for computing risk of wildfires ignition and spreading?

    Directory of Open Access Journals (Sweden)

    Alessandro Ferrarini

    2012-12-01

    Full Text Available A forest fire can be a true ecological calamity, regardless of whether it is caused by natural forces or human actions. Although it is impossible to control nature, it is possible to map wildfire risk zones, and thence minimize the frequency of wildfires and prevent damages. Wildfire risk zones are locations where a fire is likely to start, and from where it can spread to other areas. Predictions of wildfires ignitions are critical aspects of biodiversity conservation and management, and they are only possible when a reliable fire risk zone map is available. I suggest in this paper that wildfire ignition risk computed from points of past wildfires obeys the same conceptual and mathematical rules of niche models commonly applied to points of sampled plants or animals. Therefore, niche modeling can also be an inductive approach for an effective and inexpensive computation of wildfires ignition and spreading likelihood.

  4. Ignition conditions relaxation for central hot-spot ignition with an ion-electron non-equilibrium model

    Science.gov (United States)

    Fan, Zhengfeng; Liu, Jie

    2016-10-01

    We present an ion-electron non-equilibrium model, in which the hot-spot ion temperature is higher than its electron temperature so that the hot-spot nuclear reactions are enhanced while energy leaks are considerably reduced. Theoretical analysis shows that the ignition region would be significantly enlarged in the hot-spot rhoR-T space as compared with the commonly used equilibrium model. Simulations show that shocks could be utilized to create and maintain non-equilibrium conditions within the hot spot, and the hot-spot rhoR requirement is remarkably reduced for achieving self-heating. In NIF high-foot implosions, it is observed that the x-ray enhancement factors are less than unity, which is not self-consistent and is caused by assuming Te =Ti. And from this non-consistency, we could infer that ion-electron non-equilibrium exists in the high-foot implosions and the ion temperature could be 9% larger than the equilibrium temperature.

  5. Multi-dimensional Modeling of the Application of Catalytic Combustion to Homogeneous Charge Compression Ignition Engine

    Institute of Scientific and Technical Information of China (English)

    Wen Zeng; MaoZhao Xie

    2006-01-01

    The detailed surface reaction mechanism of methane on rhodium catalyst was analyzed.Comparisons between numerical simulation and experiments showed a basic agreement.The combustion process of homogeneous charge compression ignition (HCCI) engine whose piston surface has been coated with catalyst (rhodium and platinum) was numerically investigated.A multi-dimensional model with detailed chemical kinetics was built.The effects of catalytic combustion on the ignition timing,the temperature and CO concentration fields,and HC,CO and NOx emissions of the HCCI engine were discussed.The results showed the ignition timing of the HCCI engine was advanced and the emissions of HC and CO were decreased by the catalysis.

  6. The SPARK Programs: A Public Health Model of Physical Education Research and Dissemination

    Science.gov (United States)

    McKenzie, Thomas L.; Sallis, James F.; Rosengard, Paul; Ballard, Kymm

    2016-01-01

    SPARK [Sports, Play, and Active Recreation for Kids], in its current form, is a brand that represents a collection of exemplary, research-based, physical education and physical activity programs that emphasize a highly active curriculum, on-site staff development, and follow-up support. Given its complexity (e.g., multiple school levels, inclusion…

  7. Controlled auto ignition of gasoline engines; Steuerung der ottomotorischen Selbstzuendung

    Energy Technology Data Exchange (ETDEWEB)

    Sauer, Christina

    2011-07-01

    Controlled Auto Ignition allows for significant efficiency gains in combination with extremely low NO{sub x} emissions and particulate matters when compared to conventional spark ignited combustion concepts. The limiting factors for controlled auto ignition are the temperature at very low loads and the pressure gradient at higher loads. Based on experiments on a single cylinder engine with fully variable valve actuators and gasoline direct injection, the contribution under consideration reports on main parameters to control the controlled auto ignition. Detailed analyses demonstrate the impact of each parameter on self-ignition and combustion. Additionally, different methods to expand the operating range of controlled auto ignition are discussed with regard to the achievable efficiency and the required effort. One important result of this contribution is a feed-forward control which coordinates the main actuating parameters and ensures the desired combustion phasing even in dynamic mode. A regression model is developed which uses the input variables air/fuel ratio, start of injection, engine speed and fuel mass to predict the combustion phasing and the indicated mean effective pressure. Inverting this model leads to the final feed-forward control which allows to separate the effects of start of injection and exhaust valve closing. In that case exhaust valve closing controls the air/fuel ratio, while start of injection corrects the lasting deviation in combustion phasing. Using the actual air/fuel ratio as an additional input parameter ensures the required combustion phasing even in dynamic mode.

  8. Data Analysis, Pre-Ignition Assessment, and Post-Ignition Modeling of the Large-Scale Annular Cookoff Tests

    Energy Technology Data Exchange (ETDEWEB)

    G. Terrones; F.J. Souto; R.F. Shea; M.W.Burkett; E.S. Idar

    2005-09-30

    In order to understand the implications that cookoff of plastic-bonded explosive-9501 could have on safety assessments, we analyzed the available data from the large-scale annular cookoff (LSAC) assembly series of experiments. In addition, we examined recent data regarding hypotheses about pre-ignition that may be relevant to post-ignition behavior. Based on the post-ignition data from Shot 6, which had the most complete set of data, we developed an approximate equation of state (EOS) for the gaseous products of deflagration. Implementation of this EOS into the multimaterial hydrodynamics computer program PAGOSA yielded good agreement with the inner-liner collapse sequence for Shot 6 and with other data, such as velocity interferometer system for any reflector and resistance wires. A metric to establish the degree of symmetry based on the concept of time of arrival to pin locations was used to compare numerical simulations with experimental data. Several simulations were performed to elucidate the mode of ignition in the LSAC and to determine the possible compression levels that the metal assembly could have been subjected to during post-ignition.

  9. Photothermal Deoxygenation of Graphene Oxide for Distributed Ignition and Patterning Applications (Postprint)

    Science.gov (United States)

    2010-01-01

    and in high efficiency homogenous charge compression ignition ( HCCI ) engines , where ignition control is of paramount importance. 15. SUBJECT TERMS... HCCI ) engine that combines the high efficiency of a diesel engine with the low emissions of a spark ignition engine . In a typical HCCI engine , fuel... engine .[40] The high compression ratio of HCCI engines provides an efficiency increase of up to 15% over traditional spark ignition engines .[41,42

  10. Kinetic modelling of a surrogate diesel fuel applied to 3D auto-ignition in HCCI engines

    CERN Document Server

    Bounaceur, Roda; Fournet, René; Battin-Leclerc, Frédérique; Jay, S; Da Cruz, A Pires

    2007-01-01

    The prediction of auto-ignition delay times in HCCI engines has risen interest on detailed chemical models. This paper described a validated kinetic mechanism for the oxidation of a model Diesel fuel (n-decane and α-methylnaphthalene). The 3D model for the description of low and high temperature auto-ignition in engines is presented. The behavior of the model fuel is compared with that of n-heptane. Simulations show that the 3D model coupled with the kinetic mechanism can reproduce experimental HCCI and Diesel engine results and that the correct modeling of auto-ignition in the cool flame region is essential in HCCI conditions.

  11. Modeling of NO sensitization of IC engines surrogate fuels auto-ignition and combustion

    CERN Document Server

    Anderlohr, Jörg; Bounaceur, Roda; Battin-Leclerc, Frédérique

    2009-01-01

    This paper presents a new chemical kinetic model developed for the simulation of auto-ignition and combustion of engine surrogate fuel mixtures sensitized by the presence of NOx. The chemical mechanism is based on the PRF auto-ignition model (n-heptane/iso-octane) of Buda et al. [1] and the NO/n-butane/n-pentane model of Glaude et al. [2]. The later mechanism has been taken as a reference for the reactions of NOx with larger alcanes (n-heptane, iso-octane). A coherent two components engine fuel surrogate mechanism has been generated which accounts for the influence of NOx on auto-ignition. The mechanism has been validated for temperatures between 700 K and 1100 K and pressures between 1 and 10 atm covering the temperature and pressure ranges characteristic of engine post-oxidation thermodynamic conditions. Experiments used for validation include jet stirred reactor conditions for species evolution as a function of temperature, as well as diesel HCCI engine experiments for auto-ignition delay time measurements...

  12. A Model For The Optically Triggered Pseudo-Spark Thyratron Using Local Field And Beam-Bulk Methods

    Science.gov (United States)

    Pak, Hoyoung; Kushner, Mark J.

    1989-04-01

    The optically triggered psuedo-spark, also known as the Back-Lit-Thyratron (BLT), is a low pressure plasma switch having an unheated metallic cathode. In this paper, a computer simulation of the BLT is presented consisting of a 2-1/2 dimensional time dependent continuum model for electron and ion transport. The model utilizes both the local field approximation and a beam component for the electron distribution function. We find that switch closure depends critically on the formation of a virtual anode in front of the cathode hole by generation of positive space charge.

  13. Simulations and experiments on the ignition probability in turbulent premixed bluff-body flames

    Science.gov (United States)

    Sitte, Michael Philip; Bach, Ellen; Kariuki, James; Bauer, Hans-Jörg; Mastorakos, Epaminondas

    2016-05-01

    The ignition characteristics of a premixed bluff-body burner under lean conditions were investigated experimentally and numerically with a physical model focusing on ignition probability. Visualisation of the flame with a 5 kHz OH* chemiluminescence camera confirmed that successful ignitions were those associated with the movement of the kernel upstream, consistent with previous work on non-premixed systems. Performing many separate ignition trials at the same spark position and flow conditions resulted in a quantification of the ignition probability Pign, which was found to decrease with increasing distance downstream of the bluff body and a decrease in equivalence ratio. Flows corresponding to flames close to the blow-off limit could not be ignited, although such flames were stable if reached from a richer already ignited condition. A detailed comparison with the local Karlovitz number and the mean velocity showed that regions of high Pign are associated with low Ka and negative bulk velocity (i.e. towards the bluff body), although a direct correlation was not possible. A modelling effort that takes convection and localised flame quenching into account by tracking stochastic virtual flame particles, previously validated for non-premixed and spray ignition, was used to estimate the ignition probability. The applicability of this approach to premixed flows was first evaluated by investigating the model's flame propagation mechanism in a uniform turbulence field, which showed that the model reproduces the bending behaviour of the ST-versus-u‧ curve. Then ignition simulations of the bluff-body burner were carried out. The ignition probability map was computed and it was found that the model reproduces all main trends found in the experimental study.

  14. The single-zone numerical model of homogeneous charge compression ignition engine performance

    Science.gov (United States)

    Fedyanov, E. A.; Itkis, E. M.; Kuzmin, V. N.; Shumskiy, S. N.

    2017-02-01

    The single-zone model of methane-air mixture combustion in the Homogeneous Charge Compression Ignition engine was developed. First modeling efforts resulted in the selection of the detailed kinetic reaction mechanism, most appropriate for the conditions of the HCCI process. Then, the model was completed so as to simulate the performance of the four-stroke engine and was coupled by physically reasonable adjusting functions. Validation of calculations against experimental data showed acceptable agreement.

  15. Effect of Hydrogen Addition on Methane HCCI Engine Ignition Timing and Emissions Using a Multi-zone Model

    Science.gov (United States)

    Wang, Zi-han; Wang, Chun-mei; Tang, Hua-xin; Zuo, Cheng-ji; Xu, Hong-ming

    2009-06-01

    Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition timing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its application, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recirculation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.

  16. Effect of Hydrogen Addition on Methane HCCI Engine Ignition Timing and Emissions Using a Multi-zone Model

    Institute of Scientific and Technical Information of China (English)

    Zi-han Wang; Chun-mei Wang; Hua-xin Tang; Cheng-ji Zuo; Hong-ming Xu

    2009-01-01

    Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition tim-ing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its appli-cation, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NO while decreasing HC and CO emissions. Exhaust gas recir-culation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NO is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.

  17. Nonlinear dynamics analysis for combustion stability of spark-ignition engine%点燃式发动机燃烧稳定性的非线性动力学分析

    Institute of Scientific and Technical Information of China (English)

    刘帅; 王忠; 赵洋; 瞿磊; 孙波

    2016-01-01

    In order to reveal the dynamic essence of combustion cyclic fluctuations, gasoline, liquefied petroleum gas (LPG) and compressed natural gas (CNG) were burned in the ignition engine, and the cyclical fluctuations of combustion pressure were investigated using nonlinear dynamics method. The pressure data in 200 cycles were collected to discuss the regulation of in-cylinder pressure which varied with the time and to analyze cyclical fluctuation factors of the maximum break pressure. In addition, time sequences of pressure in cylinder were rebuilt three-dimensionally combined with differential coordinates, and the principles and distribution features of phase space structure changing during combustion period were studied. Phase space tracks were simplified and rebuilt by the Poincare section method to probe into the Poincare mapping points distribution of in-cylinder pressure in cross sections on whose the second derivative was zero (The second derivative of pressure was zero, Z=0) and the pressure rise rate was zero (The first derivative of pressure was zero, Y=0). The cyclical fluctuations of indicative mean effective pressures (IMEPs) were analyzed while burning 3 fuels separately. Results indicated that the cyclic fluctuation coefficient of in-cylinder pressure was 7.5% while the spark ignition engine burnt gasoline, and the coefficient increased to 7.8% and 13.8% respectively while burning LPG and CNG. The phase space track of in-cylinder pressure was a closed curve with chaos properties showing the intake and exhausting process in sharp curve and the combustion process in arc curve when the initial period structure of combustion was relatively compact and the diffusion was most obvious in the maximum of Y direction, and then it duplicated quickly after reaching the maximum at X axis direction(X axis represents pressure. Compact track distributions were observed while burning gasoline, however, there were partial combustion and lost fire cycles when LPG and CNG

  18. Burner ignition system

    Science.gov (United States)

    Carignan, Forest J.

    1986-01-21

    An electronic ignition system for a gas burner is battery operated. The battery voltage is applied through a DC-DC chopper to a step-up transformer to charge a capacitor which provides the ignition spark. The step-up transformer has a significant leakage reactance in order to limit current flow from the battery during initial charging of the capacitor. A tank circuit at the input of the transformer returns magnetizing current resulting from the leakage reactance to the primary in succeeding cycles. An SCR in the output circuit is gated through a voltage divider which senses current flow through a flame. Once the flame is sensed, further sparks are precluded. The same flame sensor enables a thermopile driven main valve actuating circuit. A safety valve in series with the main gas valve responds to a control pressure thermostatically applied through a diaphragm. The valve closes after a predetermined delay determined by a time delay orifice if the pilot gas is not ignited.

  19. Relationship between Exploding Bridgewire & Spark Initiation of Low Density PETN

    Science.gov (United States)

    Lee, Elizabeth; Drake, Rod

    2015-06-01

    Recent work has shown that the energy delivered after bridgewire burst affects the function time of an EBW detonator. The spark which is formed post bridgewire burst is the means by which the remaining fireset energy is delivered into the detonator. Therefore, by studying the characteristics of spark-gap detonators insight into the contribution of spark initiation to the functioning of EBW detonators may be achieved. Spark initiation of low density explosives consists of; (i) spark formation, (ii) spark interaction with the bed, and (iii) ignition and growth of reaction. Experiments were performed in which beds of an inert simulant were used to study the formation and propagation of sparks. The effect of the spark on inert porous beds was studied over a limited delivered energy range. The disruption of the bed was found to be dependent on the particle size / pore structure of the bed. The effect of spark initiation on a low density PETN bed was then examined, the relationship between delivered energy and function time was found to be the same as for EBW detonators. This necessitated the development of electrical diagnostic techniques to measure the energy delivered to the spark.

  20. 3rd Conference on Ignition Systems for Gasoline Engines

    CERN Document Server

    Sens, Marc

    2017-01-01

    The volume includes selected and reviewed papers from the 3rd Conference on Ignition Systems for Gasoline Engines in Berlin in November 2016. Experts from industry and universities discuss in their papers the challenges to ignition systems in providing reliable, precise ignition in the light of a wide spread in mixture quality, high exhaust gas recirculation rates and high cylinder pressures. Classic spark plug ignition as well as alternative ignition systems are assessed, the ignition system being one of the key technologies to further optimizing the gasoline engine.

  1. Propellant Flow Actuated Piezoelectric Rocket Engine Igniter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spark ignition of a bi-propellant rocket engine is a classic, proven, and generally reliable process. However, timing can be critical, and the control logic,...

  2. Propellant Flow Actuated Piezoelectric Rocket Engine Igniter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Under a Phase 1 effort, IES successfully developed and demonstrated a spark ignition concept where propellant flow drives a very simple fluid mechanical oscillator...

  3. Physical Improvements in Exciter/Igniter Units Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed Phase 2 project consists of the physical integration of our Phase 1 small, compact exciter with a "flight like" igniter or spark plug capable of...

  4. Self-ignition and oxidation of various hydrocarbons between 600 and 1000 K at high pressure: experimental study with fast compression machine and modeling; Autoinflammation et oxydation de divers hydrocarbures entre 600 et 1000 K a haute pression: etude experimentale en machine a compression rapide et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Ribaucour, M.

    2002-12-01

    Low- and intermediate-temperature oxidation and self-ignition of hydrocarbons play a major role in spark ignition, diesel and HCCI (homogenous charge compression ignition) engines. A deep understanding of the chemistry linked with both phenomena is necessary to improve the engines efficiency and to reduce the formation of pollutants. This document treats of works about the self-ignition and oxidation at high pressure of various hydrocarbons between 600 and 1000 deg. K. The experimental tool used is a fast compression machine fitted with a fast sampling system for the measurement of self-ignition delays and of the concentrations of intermediate oxidation products. The advantages and limitations of this tool are discussed. The self-ignition of various hydrocarbons is compared using pre-defined data which characterize the phenomenologies like cold flames, negative temperature coefficients and self-ignition limits. The hydrocarbons considered are pure or binary mixtures of alkanes, pent-1-ene and n-butyl-benzene. The development of high pressure oxidation reaction schemes of alkanes between 600 and 1000 deg. K is described. It is directly based on the analysis of intermediate oxidation products. This methodology is also applied to pent-1-ene and n-butyl-benzene. The construction of detailed thermo-kinetic models of oxidation and the modeling of phenomena are made for n-butane, n-heptane, for the 3 pentane isomers, for pent-1-ene and n-butyl-benzene. Finally, the perspectives of future works are evoked. They concern new modeling and new methodologies to be applied in more predictive thermo-kinetic models and the reduction of detailed models in order to include them inside fluid dynamics codes. (J.S.)

  5. Microstructure and mechanical behavior of ODS and non-ODS Fe–14Cr model alloys produced by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.A.; Castro, V. de [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Leguey, T., E-mail: leguey@fis.uc3m.es [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Muñoz, A.; Pareja, R. [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain)

    2013-05-15

    In this work the spark plasma sintering (SPS) technique has been explored as an alternative consolidation route for producing ultra-fine grained Fe–14Cr model alloys containing a dispersion of oxide nanoparticles. Elemental powders of Fe and Cr, and nanosized Y{sub 2}O{sub 3} powder have been mechanically alloyed in a planetary ball mill and rapidly sintered in a spark plasma furnace. Two alloys, with nominal compositions Fe–14%Cr and Fe–14%Cr–0.3%Y{sub 2}O{sub 3} (wt.%), have been fabricated and their microstructure and mechanical properties investigated. The results have been compared with those obtained for other powder metallurgy processed alloys of the same composition but consolidated by hot isostatic pressing. The SPS technique under the present conditions has produced Fe–14Cr materials that apparently exhibit different microstructures yielding inferior mechanical properties than the counterpart material consolidated by hot isostatic pressing. Although the presence of a dispersion of Y-rich particles is evident, the oxide dispersion strengthened (ODS) Fe–14Cr alloy consolidated by SPS exhibits poor tensile properties. The extensive decoration of the powder particle surfaces with Cr-rich precipitates and the residual porosity appear to be responsible for the impaired properties of this ODS alloy consolidated by SPS.

  6. Simulations of the Gravitationally Confined Detonation Model of Type Ia Supernovae for Multiple Ignition Points

    Science.gov (United States)

    Jordan, G. C.; Meakin, C. A.; Hearn, N.; Fisher, R. T.; Townsley, D. M.; Lamb, D. Q.; Truran, J. W.

    2009-04-01

    In this paper we present 3D simulations of the gravitationally confined detonation (GCD) model of Type Ia Supernovae with multiple ignition points as initial conditions. These simulations release more energy during the deflagration (subsonic nuclear combustion) phase than previous GCD simulations initiated with a single ignition point. Due to the increased amount of fuel consumed during the deflagration, the star undergoes a more energetic pulsation which at the time of detonation increases the amount of low-density, intermediate-mass-producing material and decreases the amount of high-density, NSE-producing material. This results in the production of approximately 0.7 M⊙ of 56Ni in the explosion, an amount that observations indicate is produced in Type Ia supernovae having typical luminosities.

  7. US Department of Energy - Office of FreedomCar and Vehicle Technologies and US Centers for Disease Control and Prevention - National Institute for Occupational Safety and Health Inter-Agency Agreement Research on "The Analysis of Genotoxic Activities of Exhaust Emissions from Mobile Natural Gas, Diesel, and Spark-Ignition Engines"

    Energy Technology Data Exchange (ETDEWEB)

    William E. Wallace

    2006-09-30

    The US Department of Energy-Office of Heavy Vehicle Technologies (now the DOE-Office of FreedomCar and Vehicle Technologies) signed an Interagency Agreement (IAA) with National Institute for Occupational Safety and Health (NIOSH), No.01-15 DOE, 9/4/01, for 'The analysis of genotoxic activities of exhaust emissions from mobile natural gas, diesel, and spark-ignition engines'; subsequently modified on 3/27/02 (DOE IAG No.01-15-02M1); subsequently modified 9/02/03 (IAA Mod No. 01-15-03M1), as 'The analysis of genotoxic activities of exhaust emissions from mobile internal combustion engines: identification of engine design and operational parameters controlling exhaust genotoxicity'. The DOE Award/Contract number was DE-AI26-01CH11089. The IAA ended 9/30/06. This is the final summary technical report of National Institute for Occupational Safety and Health research performed with the US Department of Energy-Office of FreedomCar and Vehicle Technologies under that IAA: (A) NIOSH participation was requested by the DOE to provide in vitro genotoxicity assays of the organic solvent extracts of exhaust emissions from a suite of in-use diesel or spark-ignition vehicles; (B) research also was directed to develop and apply genotoxicity assays to the particulate phase of diesel exhaust, exploiting the NIOSH finding of genotoxicity expression by diesel exhaust particulate matter dispersed into the primary components of the surfactant coating the surface of the deep lung; (C) from the surfactant-dispersed DPM genotoxicity findings, the need for direct collection of DPM aerosols into surfactant for bioassay was recognized, and design and developmental testing of such samplers was initiated.

  8. High temperature shock tube experiments and kinetic modeling study of diisopropyl ketone ignition and pyrolysis

    KAUST Repository

    Barari, Ghazal

    2017-03-10

    Diisopropyl ketone (DIPK) is a promising biofuel candidate, which is produced using endophytic fungal conversion. In this work, a high temperature detailed combustion kinetic model for DIPK was developed using the reaction class approach. DIPK ignition and pyrolysis experiments were performed using the UCF shock tube. The shock tube oxidation experiments were conducted between 1093K and 1630K for different reactant compositions, equivalence ratios (φ=0.5–2.0), and pressures (1–6atm). In addition, methane concentration time-histories were measured during 2% DIPK pyrolysis in argon using cw laser absorption near 3400nm at temperatures between 1300 and 1400K near 1atm. To the best of our knowledge, current ignition delay times (above 1050K) and methane time histories are the first such experiments performed in DIPK at high temperatures. Present data were used as validation targets for the new kinetic model and simulation results showed fair agreement compared to the experiments. The reaction rates corresponding to the main consumption pathways of DIPK were found to have high sensitivity in controlling the reactivity, so these were adjusted to attain better agreement between the simulation and experimental data. A correlation was developed based on the experimental data to predict the ignition delay times using the temperature, pressure, fuel concentration and oxygen concentration.

  9. An experimental investigation of a lean-burn natural-gas pre-chamber spark ignition engine for cogeneration; Swiss Motor. Modification d'un moteur diesel pour le fonctionnement au gaz naturel en cogeneration. Fonctionnement avec prechambre de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Roethlisberger, R.; Favrat, D.

    2001-07-01

    This thesis presented at the Department of Mechanical Engineering of the Swiss Federal Institute of Technology in Lausanne describes the conversion and testing of a commercial diesel engine for use as a lean-burn, natural gas, pre-chamber, spark ignition engine with a rated power of 150 kW, in combined heat and power (CHP) plants. The objective of the investigations - to evaluate the potential of reducing exhaust gas emissions - is discussed in detail with respect to NO{sub x} and CO emissions. The approach adopted includes both experimental work and numerical simulation. The report describes the testing facilities used. The results obtained with experimental spark-plug configurations based on simulation results are presented and the influence of various pre-chamber configuration variants are discussed. The results of the tests are presented and the significant reduction of NO{sub x}, CO and unburned-hydrocarbon (THC) emissions are discussed. The authors state that the engine, which achieves a fuel efficiency of more than 36.5%, fulfils the Swiss requirements on exhaust gas emissions. Also, ways of compensating for the slight loss in fuel-conversion efficiency in the pre-chamber configuration are discussed.

  10. SI Engine with repetitive NS spark plug

    Science.gov (United States)

    Pancheshniy, Sergey; Nikipelov, Andrey; Anokhin, Eugeny; Starikovskiy, Andrey; Laplase Team; Mipt Team; Pu Team

    2013-09-01

    Now de-facto the only technology for fuel-air mixtures ignition in IC engines exists. It is a spark discharge of millisecond duration in a short discharge gap. The reason for such a small variety of methods of ignition initiation is very specific conditions of the engine operation. First, it is very high-pressure of fuel-air mixture - from 5-7 atmospheres in old-type engines and up to 40-50 atmospheres on the operating mode of HCCI. Second, it is a very wide range of variation of the oxidizer/fuel ratio in the mixture - from almost stoichiometric (0.8-0.9) at full load to very lean (φ = 0.3-0.5) mixtures at idle and/or economical cruising mode. Third, the high velocity of the gas in the combustion chamber (up to 30-50 m/s) resulting in a rapid compression of swirling inlet flow. The paper presents the results of tests of distributed spark ignition system powered by repetitive pulse nanosecond discharge. Dynamic pressure measurements show the increased pressure and frequency stability for nanosecond excitation in comparison with the standard spark plug. Excitation by single nanosecond high-voltage pulse and short train of pulses was examined. In all regimes the nanosecond pulsed excitation demonstrate a better performance.

  11. Modeling Laser-Plasma Interactions at Direct-Drive Ignition-Relevant Plasma Conditions at the National Ignition Facility

    Science.gov (United States)

    Solodov, A. A.; Rosenberg, M. J.; Myatt, J. F.; Epstein, R.; Seka, W.; Hohenberger, M.; Short, R. W.; Shaw, J. G.; Regan, S. P.; Froula, D. H.; Radha, P. B.; Bates, J. W.; Schmitt, A. J.; Michel, P.; Moody, J. D.; Ralph, J. E.; Turnbull, D. P.; Barrios, M. A.

    2016-10-01

    Laser-plasma interaction instabilities, such as two-plasmon decay (TPD) and stimulated Raman scattering (SRS), can be detrimental for direct-drive inertial confinement fusion because of target preheat by generated high-energy electrons. The radiation-hydrodynamics code DRACO has been used to design planar-target experiments that generate plasma and interaction conditions relevant to direct-drive-ignition designs (IL 1015 W / cm 2 , Te > 3 KeV density gradient scale lengths of Ln 600 μm) . The hot-electron temperature of 40to50keV and the fraction of laser energy converted to hot electrons of 0.5to were inferred based on comparing the simulated and experimentally observed x-ray emission when the laser intensity at the quarter-critical surface increased from 6 to 15 ×1014 W / cm 2 . The measured SRS energy was sufficient to explain the observed total energy in hot electrons. Implications for ignition-scale direct-drive experiments and hot-electron preheat mitigation using mid- Z ablators will be discussed. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  12. Igniters for Liquid Oxygen/Liquid Methane Technology Development

    Science.gov (United States)

    Osborne, Robin J.; Elam, Sandra K.; Peschel, William P.

    2008-01-01

    As part of NASA's technology development of liquid methane / liquid oxygen engines for future exploration missions, two different igniters were recently studied at NASA Marshall Space Flight Center. The first igniter tested was an impinging injection, spark-initiated torch igniter, and the second was a microwave-generated plasma igniter. The purpose of the ignition tests was to define the ignition limits under vacuum conditions and characterize the transient start-up performance as a function of propellant mixture ratio (MR), mass flow rates, inlet temperatures, and pre-ignition chamber pressure. In addition, for the impinging igniter two different spark plugs were tested, and for the microwave igniter the magnetron filament warm-up time and the magnetron input power were both varied. The results gathered from these tests indicated that the impinging igniter is capable of operating over an MR range of 2 - 27, with methane and oxygen inlet temperatures as low as -161 F and -233 F, respectively. The microwave igniter was tested over an MR range of 2 - 9, with methane and oxygen inlet temperatures as low as -90 F and -200 F, respectively. The microwave igniter achieved ignition over this range, although an upper ignition limit was determined for the oxidizer mass flow rate. In general, the torch exhaust temperatures for the microwave igniter were not as high as those attained with the impinging igniter. The microwave igniter, however, was hot-fired 17 times and was still operational, whereas the impinging igniter spark plugs experienced thermal shock and erosion over nine hot-fire tests. It was concluded that for the microwave igniter better mixing of the propellants might be required in order to both raise the torch exhaust temperature and decrease the required magnetron input power, and for the impinging igniter the spark plug position within the igniter chamber should be varied in future tests to identify a more optimal location. All of the igniter tests were

  13. Modeling of laser-induced damage and optic usage at the National Ignition Facility

    Science.gov (United States)

    Liao, Zhi M.; Nostrand, Mike; Carr, Wren; Bude, Jeff; Suratwala, Tayyab I.

    2016-07-01

    Modeling of laser-induced optics damage has been introduced to benchmark existing optic usage at the National Ignition Facility (NIF) which includes the number of optics exchanged for damage repair. NIF has pioneered an optics recycle strategy to allow it to run the laser at capacity since fully commissioned in 2009 while keeping the cost of optics usage manageable. We will show how the damage model is being used to evaluate strategies to streamline our optics loop efficiency, as we strive to increase the laser shot rate without increasing operating costs.

  14. An Application Research of Linear Model in the Advertising System Based on Spark%基于 Spark 的线性模型在广告投放系统中的应用研究

    Institute of Scientific and Technical Information of China (English)

    林穗; 赵菲

    2016-01-01

    针对在线广告投放中对实时性和高精确度的要求,对比了Hadoop和Spark两种主流平台在实现流程及效率方面的差异,提出了将线性模型结合Spark技术应用在广告投放系统中,并从数值特征、迭代和步长等方面对模型进行优化。经测试表明,调优后的精确度有5%至10%的提升。%The online advertisement is the most important model of Internet profit.It makes the compu-ting advertising a hot point of current research.For the real-time requirement and the high accuracy re-quirement in the online advertising system, the difference between the implementation and efficiency is compared based on the two popular platforms of Hadoop and Spark.And then a linear model is proposed combined with the technology of Spark to be applied in the advertising system.Finally the linear model is optimized from the aspect of numerical characteristics, iteration and step size.The testing result shows that the accuracy has a 5%to 10%increase after the optimization.

  15. A Hot Spots Ignition Probability Model for Low-Velocity Impacted Explosive Particles Based on the Particle Size and Distribution

    Directory of Open Access Journals (Sweden)

    Hong-fu Guo

    2017-01-01

    Full Text Available Particle size and distribution play an important role in ignition. The size and distribution of the cyclotetramethylene tetranitramine (HMX particles were investigated by Laser Particle Size Analyzer Malvern MS2000 before experiment and calculation. The mean size of particles is 161 μm. Minimum and maximum sizes are 80 μm and 263 μm, respectively. The distribution function is like a quadratic function. Based on the distribution of micron scale explosive particles, a microscopic model is established to describe the process of ignition of HMX particles under drop weight. Both temperature of contact zones and ignition probability of powder explosive can be predicted. The calculated results show that the temperature of the contact zones between the particles and the drop weight surface increases faster and higher than that of the contact zones between two neighboring particles. For HMX particles, with all other conditions being kept constant, if the drop height is less than 0.1 m, ignition probability will be close to 0. When the drop heights are 0.2 m and 0.3 m, the ignition probability is 0.27 and 0.64, respectively, whereas when the drop height is more than 0.4 m, ignition probability will be close to 0.82. In comparison with experimental results, the two curves are reasonably close to each other, which indicates our model has a certain degree of rationality.

  16. Modeling human-caused forest fire ignition for assessing forest fire danger in Austria

    Directory of Open Access Journals (Sweden)

    Arndt N

    2013-07-01

    Full Text Available Forest fires have not been considered as a significant threat for mountain forests of the European Alpine Space so far. Climate change and its effects on nature, ecology, forest stand structure and composition, global changes according to demands of society and general trends in the provision of ecosystem services are potentially going to have a significant effect on fire ignition in the future. This makes the prediction of forest fire ignition essential for forest managers in order to establish an effective fire prevention system and to allocate fire fighting resources effectively, especially in alpine landscapes. This paper presents a modelling approach for predicting human-caused forest fire ignition by a range of socio-economic factors associated with an increasing forest fire danger in Austria. The relationship between touristic activities, infrastructure, agriculture and forestry and the spatial occurrence of forest fires have been studied over a 17-year period between 1993 and 2009 by means of logistic regression. 59 independent socio-economic variables have been analysed with different models and validated with heterogeneous subsets of forest fire records. The variables included in the final model indicate that railroad, forest road and hiking trail density together with agricultural and forestry developments may contribute significantly to fire danger. The final model explains 60.5% of the causes of the fire events in the validation set and allows a solid prediction. Maps showing the fire danger classification allow identifying the most vulnerable forest areas in Austria and are used to predict the fire danger classes on municipality level.

  17. Efficiency of SparkJet

    Science.gov (United States)

    Golbabaei-Asl, M.; Knight, D.; Wilkinson, S.

    2013-01-01

    The thermal efficiency of a SparkJet is evaluated by measuring the impulse response of a pendulum subject to a single spark discharge. The SparkJet is attached to the end of a pendulum. A laser displacement sensor is used to measure the displacement of the pendulum upon discharge. The pendulum motion is a function of the fraction of the discharge energy that is channeled into the heating of the gas (i.e., increasing the translational-rotational temperature). A theoretical perfect gas model is used to estimate the portion of the energy from the heated gas that results in equivalent pendulum displacement as in the experiment. The earlier results from multiple runs for different capacitances of C = 3, 5, 10, 20, and 40(micro)F demonstrate that the thermal efficiency decreases with higher capacitive discharges.1 In the current paper, results from additional run cases have been included and confirm the previous results

  18. Ignition assist systems for direct-injected, diesel cycle, medium-duty alternative fuel engines: Final report phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Chan, A.K.

    2000-02-23

    This report is a summary of the results of Phase 1 of this contract. The objective was to evaluate the potential of assist technologies for direct-injected alternative fuel engines vs. glow plug ignition assist. The goal was to demonstrate the feasibility of an ignition system life of 10,000 hours and a system cost of less than 50% of the glow plug system, while meeting or exceeding the engine thermal efficiency obtained with the glow plug system. There were three tasks in Phase 1. Under Task 1, a comprehensive review of feasible ignition options for DING engines was completed. The most promising options are: (1) AC and the ''SmartFire'' spark, which are both long-duration, low-power (LDLP) spark systems; (2) the short-duration, high-power (SDHP) spark system; (3) the micropilot injection ignition; and (4) the stratified charge plasma ignition. Efforts concentrated on investigating the AC spark, SmartFire spark, and short-duration/high-power spark systems. Using proprietary pricing information, the authors predicted that the commercial costs for the AC spark, the short-duration/high-power spark and SmartFire spark systems will be comparable (if not less) to the glow plug system. Task 2 involved designing and performing bench tests to determine the criteria for the ignition system and the prototype spark plug for Task 3. The two most important design criteria are the high voltage output requirement of the ignition system and the minimum electrical insulation requirement for the spark plug. Under Task 3, all the necessary hardware for the one-cylinder engine test was designed. The hardware includes modified 3126 cylinder heads, specially designed prototype spark plugs, ignition system electronics, and parts for the system installation. Two 3126 cylinder heads and the SmartFire ignition system were procured, and testing will begin in Phase 2 of this subcontract.

  19. Spark ignition engines and diesel engines. Design, function and calculation of two-stroke and four-stroke engines; 11. ed.; Otto- und Dieselmotoren. Arbeitsweise, Aufbau und Berechnung von Zweitakt- und Viertakt-Verbrennungsmotoren

    Energy Technology Data Exchange (ETDEWEB)

    Grohe, H.

    1995-12-31

    The book presents an outline of the design and function of internal combustion engines. It comprises the following chapters: Historical review; fundamentals in mechanics and thermodynamics; calculation methods; ignition; knocking; mixing; load cycles; supercharging; components. (HW) [Deutsch] Das Buch liefert einen Ueberblick ueber Aufbau und Arbeitsweise des Verbrennungsmotors. Aufgliederung in folgende Kapitel: - Historisches Rueckblick; - Mechanische und waermetechnische Grundlagen; - Berechungsverfahren; - Zuendung; - Klopfen; - Gemischbildung; - Ladungswechsel; - Aufladung; - Bauteile. (HW)

  20. Assessing the risk of ignition in the Russian far east within a modeling framework of fire threat.

    Science.gov (United States)

    Loboda, Tatiana V; Csiszar, Ivan A

    2007-04-01

    The forests of high biological importance in the Russian Far East (RFE) have been experiencing increasing pressure from growing demands for natural resources under the changing economy of post-Soviet Russia. This pressure is further amplified by the rising threat of large and catastrophic fire occurrence, which threatens both the resources and the economic potential of the region. In this paper we introduce a conceptual Fire Threat Model (FTM) and use it to provide quantitative assessment of the risk of ignition in the Russian Far East. The remotely sensed data driven FTM is aimed at evaluating potential wildland fire occurrence and its impact and recovery potential for a given resource. This model is intended for use by resource managers to assist in assessing current levels of fire threat to a given resource, projecting the changes in fire threat under changing climate and land use, and evaluating the efficiency of various management approaches aimed at minimizing the fire impact. Risk of ignition (one of the major uncertainties within fire threat modeling) was analyzed using the MODIS active fire product. The risk of ignition in the RFE is shown to be highly variable in spatial and temporal domains. However, the number of ignition points is not directly proportional to the amount of fire occurrence in the area. Fire ignitions in the RFE are strongly linked to anthropogenic activity (transportation routes, settlements, and land use). An increase in the number of fire ignitions during summer months could be attributed to (1) disruption of the summer monsoons and subsequent changes in fire weather and (2) an increase in natural sources of fire ignitions.

  1. Evaluation of Innovative High Pulse Rate, Purged Spark Gap Concepts

    Science.gov (United States)

    1989-06-01

    gugh the switch and the pressure loss through the gas circulation system. The pressure loss is the sum of the losses in the spark gap , flow ducting...developed to solve the mass, momentum, and energy conservation equations which govern the purging process in a spark gap flow channel following arc...formation. [2,3] In this model, gas properties and spark gap flow channel area varied with distance along the flow axis from the spark gap and with

  2. Estudio del empleo de un convertidor catalítico para las emisiones gaseosas en un motor de ignición por chispa usando etanol como combustible. // Study of the employment of a catalytic convertor for the gassy emissions in an spark ignition engine using et

    Directory of Open Access Journals (Sweden)

    K. C. R. Martins

    2005-01-01

    Full Text Available Con este trabajo de investigación se estudia el índice de emisiones gaseosas en un motor de ignición por chispa movido conetanol y se analiza el control de estas emisiones con aplicación de un convertidor catalítico platino/paladio (Pt/Pd en elsistema de descarga del motor. Fueron realizados ensayos dinamométricos de un motor de combustión interna MCI paraanalizar las emisiones y el control de estas, en condiciones operacionales, en función de la rotación y ángulo de avance deignición. El convertidor catalítico alcanzó un 75% de eficiencia cuando el ángulo de avance de ignición del motor aumentópara 16o. Se observó que en rotaciones de 2000 r.p.m el convertidor catalítico presentó mayor reducción de las emisionesde hidrocarburos no quemados HC, monóxido de carbono CO y óxidos de nitrógeno NOx. Con la aplicación de unconvertidor catalítico en un vehículo se debe estandarizar nuevas regulaciones en cuanto al ángulo de avance de igniciónpara optimizar el funcionamiento del motor.Palabras claves: Convertidor catalítico; emisiones de escape; eficiencia catalítica; etanol.____________________________________________________________________________Summary.With this investigation work the index of gassy emissions is studied in an spark ignition engine using ethanol, the control ofthese emissions is analyzed with application of a platinum/palladium (Pt/Pd catalytic convector in the engine dischargesystem. Rehearsals carried out in engines in order to analyze the emissions and the control of these, under operationalconditions, in function of the rotation and angle of ignition advance were carried out. The catalytic convector reaches 75%of efficiency when the ignition advance angle of the engine increased to 16o. It was observed that in rotations of 2000r.p.m the catalytic convector presented bigger reduction of the emissions of non-burnt hydrocarbons HC, monoxide ofcarbon CO and nitrogen oxides NOx. With the application of a

  3. Fastdata processing with Spark

    CERN Document Server

    Karau, Holden

    2013-01-01

    This book will be a basic, step-by-step tutorial, which will help readers take advantage of all that Spark has to offer.Fastdata Processing with Spark is for software developers who want to learn how to write distributed programs with Spark. It will help developers who have had problems that were too much to be dealt with on a single computer. No previous experience with distributed programming is necessary. This book assumes knowledge of either Java, Scala, or Python.

  4. ElectroSpark Deposition

    Science.gov (United States)

    2007-01-25

    ElectroSpark Deposition Hard Chrome Alternatives Team Joint Cadmium Alternatives Team Canadian Hard Chrome Alternatives Team Joint Group on Pollution...00-2007 to 00-00-2007 4. TITLE AND SUBTITLE ElectroSpark Deposition 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...Processes, Inc. ElectroSpark Deposition (ESD) Results of Materials Testing and Technology Insertion January 25, 2007 Advanced Surfaces And Processes, Inc. 3

  5. Experimental and Kinetic Modeling Study of Methanol Ignition and Oxidation at High Pressure

    DEFF Research Database (Denmark)

    Aranda, V.; Christensen, J. M.; Alzueta, Maria

    2013-01-01

    A detailed chemical kinetic model for oxidation of CH3OH at high pressure and intermediate temperatures has been developed and validated experimentally. Ab initio calculations and Rice–Ramsperger–Kassel–Marcus/transition state theory (RRKM/TST) analysis were used to obtain rate coefficients for CH...... the conditions studied, the onset temperature for methanol oxidation was not dependent on the stoichiometry, whereas increasing pressure shifted the ignition temperature toward lower values. Model predictions of the present experimental results, as well as rapid compression machine data from the literature, were...... and lower pressures. At the high pressures, the modeling predictions for onset of reaction were particularly sensitive to the CH 3 OH + HO 2⇌ CH 2 OH +H2O2reaction....

  6. Relative importance of fuel management, ignition management and weather for area burned: Evidence from five landscape-fire-succession models

    Science.gov (United States)

    Geoffrey J. Cary; Mike D. Flannigan; Robert E. Keane; Ross A. Bradstock; Ian D. Davies; James M. Lenihan; Chao Li; Kimberley A. Logan; Russell A. Parsons

    2009-01-01

    The behaviour of five landscape fire models (CAFE, FIRESCAPE, LAMOS(HS), LANDSUM and SEMLAND) was compared in a standardised modelling experiment. The importance of fuel management approach, fuel management effort, ignition management effort and weather in determining variation in area burned and number of edge pixels burned (a measure of potential impact on assets...

  7. Analysis of cyclic variability in spark-assisted HCCI combustion using a double Wiebe function

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Robert M [ORNL; Glewen, William J [ORNL; Edwards, Kevin Dean [ORNL; Daw, C Stuart [ORNL

    2008-01-01

    A heuristic algorithm based on a double Wiebe function is proposed for estimating the relative importance of distinct combustion modes (propagating flame and compression ignition) occurring within individual combustion cycles as an engine is transitioned from conventional spark-ignited (SI) combustion to homogeneous charge compression ignition (HCCI). The proposed algorithm automates the analysis and categorization of pressure measurements from large numbers of individual cycles, providing new insight into the unstable combustion processes occurring during mode transition. Similar techniques could potentially be utilized for on-line diagnostics and control of the balance between SI and HCCI combustion in spark-assisted HCCI.

  8. Start of Injection Impacts on Performance of a Direct-injection Spark-ignition Engine%喷油开始时刻对缸内直喷汽油机性能的影响

    Institute of Scientific and Technical Information of China (English)

    韩文艳; 许思传; 周岳康; 任健康

    2013-01-01

    通过对某涡轮增压缸内直喷汽油机缸内流动、混合气形成及燃烧过程的数值模拟,并借助发动机台架试验中获得的油耗、排放及燃烧数据,研究了喷油开始时刻对发动机性能的影响.结果显示,对于5 000 r ·min-1工况,喷油开始时刻为400°曲轴转角是混合气雾化混合的最佳方案,此时混合气分布比较均匀且点火时刻火花塞附近具有较高的湍动能,10%~90%燃烧持续期最短且HC排放较低,从而使其具有最佳的燃油经济性与燃烧稳定性.而2 000 r· min-1工况的最佳喷油开始时刻推迟了30°曲轴转角.喷油提前,壁面油膜量增加,混合气当量比下降及火花塞附近较低的湍动能使得燃烧速率降低,因此HC排放、燃油经济性及燃烧稳定性均会变差.同样的情况也出现在推迟喷油中,由于混合不充分使得点火时刻混合气均匀度下降,从而使发动机性能恶化.%A numerical simulation was carried out on cylinder flow, mixture formation and combustion process of a turbo-charged gasoline direct injection engine, and then on the basis of the test data about the break specific fuel consumption, emission and combustion, an analysis was made of the best time to start the injection on engine performance.The results show in the case of 5 000 r·min-1, the injection started at 400° crank angle obtains an optimal mixture formation, when it presents the best fuel economy and combustion stability with distribution, the higher turbulence kinetic energy around the spark plug at spark time and the shortest 10% ~90% burning duration as well as the lower HC emission.While the best time to start the injection is retarded at 30° crank angle with 2 000 r·min-1.When the injection starts in advance, the wall film increases, and the decreased equivalence ratio and the lower turbulence kinetic energy around spark lead to a lower burning rate, so HC emissions, fuel economy and combustion stability may go bad

  9. Spark-hdf5

    Energy Technology Data Exchange (ETDEWEB)

    2016-07-05

    The spark-hdf5 package is an extension to the Apache Spark program to allow native access to HDF5 files. It allows users to query the structured files using SQL-like syntax, and can parallelize large queries across several workers.

  10. Electric Spark Discharges in Water. Low-energy Nuclear Transmutations and Light Leptonic Magnetic Monopoles in an Extended Standard Model

    Science.gov (United States)

    Stumpf, Harald

    2017-08-01

    Light leptonic magnetic monopoles were predicted by Lochak [G. Lochak, Intern. J. Theor. Phys. 24, 1019 (1985).]. Experimental indications based on nuclear transmutations were announced by Urutskoiev et al. [L. I. Urutskoiev, V. I. Liksonov, V. G. Tsinoev, Ann. Fond. L. de Broglie 27, Nr.4, 791 (2002).] and Urutskoev [L. J. Urutskoev, Ann. Fond. L. de Broglie 29, 1149 (2004).]. A theoretical interpretation of these transmutations is proposed under the assumption that light leptonic magnetic monopoles are created during spark discharges in water. The latter should be excited neutrinos according to Lochak. This hypothesis enforces the introduction of an extended Standard Model described in previous papers. The most important results of this study are (i) that multiple proton captures are responsible for the variety of transmutations and that leptonic magnetic monopoles are involved in these processes (ii) that electromagnetic duality can be established for bound states of leptonic monopoles although massive monopoles are in general unstable (iii) that criteria for the emission of leptonic magnetic monopoles and for their catalytic effect on weak decays are set up and elaborated. The study can be considered as a contribution to the efforts of Urutskoiev and Lochak to understand the reasons for accidents in power plants.

  11. In-cylinder flow field in a spark-ignited natural gas engine. 1st Report. In-cylinder flow visualization by PTV; Hibana tenkashiki tennen gas kikan no nenshoshitsunai ni okeru ryudo tokusei. 1. PTV ni yoru ryudoba no kashika

    Energy Technology Data Exchange (ETDEWEB)

    Fukano, Y.; Hisaki, H.; Kida, S. [Osaka Gas Co. Ltd., Osaka (Japan); Kadota, T. [University of Osaka Prefecture, Osaka (Japan). Faculty of Engineering

    1998-02-25

    In-cylinder flow field in a spark-ignited natural gas engine was investigated by the laser light sheet PTV method, which can analyze flow field in a short time. Using a single-cylinder visualization engine, flow field was measured right below and 10 mm, 20 mm, and 40 mm below cylinder head, at various crank angles in intake, compression, and expansion strokes. The results showed that induction-generated swirl was getting concentric to the cylinder center in compression stroke, and was shifted to the outward radial direction in expansion stroke. Swirl velocity increases with the lapse of time, showing its maximum around 20deg BTDC during compression stroke, and varies from cycle to cycle within {+-}5% to its maximum velocity. Squish velocity shows its inward maximum and outward maximum around 20deg BTDC and 20deg ATDC, respectively, and varies from cycle to cycle within {+-}8% to its maximum outward velocity. The maximum outward squish velocity in expansion stroke is about twice as large as the maximum inward squish velocity in compression stroke. 11 refs.

  12. Storage Reliability of Missile Materiel Program. Igniters and Safe and Arm Device Analysis.

    Science.gov (United States)

    1976-05-01

    currenk is applied to the squibs which ignite the pyrogen motor. Hot gases from the pyrogen motor exhaust up the blast tube to the rocket motor...acts as a back- up in case of failure of the primary ignition spark plug. The hot gas igniter has a burn-time of 80 to 100 milliseconds. It consists of...Reliability The data collected todate indicates two separate character- istics effecting the reliability of igniters and safe and arm devices. The first

  13. The Effect of Particle Properties on Hot Particle Spot Fire Ignition

    Science.gov (United States)

    Zak, Casey David

    The ignition of natural combustible material by hot metal particles is an important fire ignition pathway by which wildland and wildland-urban-interface spot fires are started. There are numerous cases reported of wild fires started by clashing power-lines or from sparks generated by machines or engines. Similarly there are many cases reported of fires caused by grinding, welding and cutting sparks. Up to this point, research on hot particle spot fire ignition has largely focused on particle generation and transport. A small number of studies have examined what occurs after a hot particle contacts a natural fuel bed, but until recently the process remained poorly understood. This work describes an investigation of the effect of particle size, temperature and thermal properties on the ability of hot particles to cause flaming ignition of cellulosic fuel beds. Both experimental and theoretical approaches are used, with a focus on understanding the physics underlying the ignition process. For the experimental study, spheres of stainless steel, aluminum, brass and copper are heated in a tube furnace and dropped onto a powdered cellulose fuel bed; the occurrence of flaming ignition or lack thereof is visually observed and recorded. This procedure is repeated a large number of times for each metal type, varying particle diameter from 2 to 11 mm and particle temperature between 575 and 1100°C. The results of these experiments are statistically analyzed to find approximate ignition boundaries and identify boundary trends with respect to the particle parameters of interest. Schlieren images recorded during the ignition experiments are also used to more accurately describe the ignition process. Based on these images, a simple theoretical model of hot particle spot fire ignition is developed and used to explore the experimental trends further. The model under-predicts the minimum ignition temperatures required for small spheres, but agrees qualitatively with the experimental

  14. An Investigation Into Bayesian Networks for Modeling National Ignition Facility Capsule Implosions

    Energy Technology Data Exchange (ETDEWEB)

    Mitrani, J

    2008-08-18

    Bayesian networks (BN) are an excellent tool for modeling uncertainties in systems with several interdependent variables. A BN is a directed acyclic graph, and consists of a structure, or the set of directional links between variables that depend on other variables, and conditional probabilities (CP) for each variable. In this project, we apply BN's to understand uncertainties in NIF ignition experiments. One can represent various physical properties of National Ignition Facility (NIF) capsule implosions as variables in a BN. A dataset containing simulations of NIF capsule implosions was provided. The dataset was generated from a radiation hydrodynamics code, and it contained 120 simulations of 16 variables. Relevant knowledge about the physics of NIF capsule implosions and greedy search algorithms were used to search for hypothetical structures for a BN. Our preliminary results found 6 links between variables in the dataset. However, we thought there should have been more links between the dataset variables based on the physics of NIF capsule implosions. Important reasons for the paucity of links are the relatively small size of the dataset, and the sampling of the values for dataset variables. Another factor that might have caused the paucity of links is the fact that in the dataset, 20% of the simulations represented successful fusion, and 80% didn't, (simulations of unsuccessful fusion are useful for measuring certain diagnostics) which skewed the distributions of several variables, and possibly reduced the number of links. Nevertheless, by illustrating the interdependencies and conditional probabilities of several parameters and diagnostics, an accurate and complete BN built from an appropriate simulation set would provide uncertainty quantification for NIF capsule implosions.

  15. PM Emission Characteristics of Spark-Ignition Engine Fueled with Ethanol/Gasoline Blends%乙醇汽油混合燃料颗粒物排放的特性

    Institute of Scientific and Technical Information of China (English)

    白代彤; 王锡斌; 蔡建; 张红阳

    2012-01-01

    在一台火花点火式发动机上,对燃用不同比例的乙醇汽油混合燃料时的颗粒物排放特性的影响因素进行研究.结果表明,中小负荷时汽油掺醇能够有效地降低颗粒物排放的总数目浓度和质量浓度,如汽油机在平均有效压力为0.34MPa、乙醇掺混比为20%时,颗粒物的总数目浓度和总质量浓度分别比纯汽油下降了84.3%和50.7%.乙醇掺混比的增加使得数目浓度向小粒径方向移动,而点火提前角的减小、平均有效压力的增大和混合气过浓均会使颗粒物数目浓度的峰值向大粒径方向偏移.平均有效压力的减小、点火的推迟和过量空气系数的增加均能使颗粒物的总数目浓度和质量浓度降低.%Experimental studies on particle number and mass concentration distribution were conducted by us- ing electrical low pressure impactor in an SI engine fueled with ethanol/gasoline blends. The total number and mass concentration of particle can be effectively decreased fueled with ethanol/gasoline blends. The total number and mass concentration of particle fueled with E20 decreases by 84.3% and 50.7%, respectively at break mean effective pressure (BMEP) of 0.34 MPa. The diameter of peak number concentration moves to large size direction with increasing the brake mean effective pressure. Delay of ignition timing, decrease of excess air ratio and increase of BMEP move the peak number concentration to large size direction. The total number and mass con- centration of particle decrease with decreasing brake mean effective pressure, advancing ignition timing and increasing excess air ratio.

  16. An Integrated Model of Care: A Visit to The SPARK Center, a Program of Boston Medical Center

    Science.gov (United States)

    Griest, Christa

    2010-01-01

    This article features The SPARK Center, a program of Boston Medical Center, located in Mattapan, Massachusetts. The Center has pioneered a whole-child approach to address the multi-dimensional needs of Boston's most at-risk children, recognizing that vulnerable children need more than educational supports to flourish. The Center's integrated model…

  17. Development of Spectral and Atomic Models for Diagnosing Energetic Particle Characteristics in Fast Ignition Experiments

    Energy Technology Data Exchange (ETDEWEB)

    MacFarlane, Joseph J [Prism Computational Sciences

    2009-08-07

    This Final Report summarizes work performed under DOE STTR Phase II Grant No. DE-FG02-05ER86258 during the project period from August 2006 to August 2009. The project, “Development of Spectral and Atomic Models for Diagnosing Energetic Particle Characteristics in Fast Ignition Experiments,” was led by Prism Computational Sciences (Madison, WI), and involved collaboration with subcontractors University of Nevada-Reno and Voss Scientific (Albuquerque, NM). In this project, we have: Developed and implemented a multi-dimensional, multi-frequency radiation transport model in the LSP hybrid fluid-PIC (particle-in-cell) code [1,2]. Updated the LSP code to support the use of accurate equation-of-state (EOS) tables generated by Prism’s PROPACEOS [3] code to compute more accurate temperatures in high energy density physics (HEDP) plasmas. Updated LSP to support the use of Prism’s multi-frequency opacity tables. Generated equation of state and opacity data for LSP simulations for several materials being used in plasma jet experimental studies. Developed and implemented parallel processing techniques for the radiation physics algorithms in LSP. Benchmarked the new radiation transport and radiation physics algorithms in LSP and compared simulation results with analytic solutions and results from numerical radiation-hydrodynamics calculations. Performed simulations using Prism radiation physics codes to address issues related to radiative cooling and ionization dynamics in plasma jet experiments. Performed simulations to study the effects of radiation transport and radiation losses due to electrode contaminants in plasma jet experiments. Updated the LSP code to generate output using NetCDF to provide a better, more flexible interface to SPECT3D [4] in order to post-process LSP output. Updated the SPECT3D code to better support the post-processing of large-scale 2-D and 3-D datasets generated by simulation codes such as LSP. Updated atomic physics modeling to provide for

  18. Capsule modeling of high foot implosion experiments on the National Ignition Facility

    Science.gov (United States)

    Clark, D. S.; Kritcher, A. L.; Milovich, J. L.; Salmonson, J. D.; Weber, C. R.; Haan, S. W.; Hammel, B. A.; Hinkel, D. E.; Marinak, M. M.; Patel, M. V.; Sepke, S. M.

    2017-05-01

    This paper summarizes the results of detailed, capsule-only simulations of a set of high foot implosion experiments conducted on the National Ignition Facility (NIF). These experiments span a range of ablator thicknesses, laser powers, and laser energies, and modeling these experiments as a set is important to assess whether the simulation model can reproduce the trends seen experimentally as the implosion parameters were varied. Two-dimensional (2D) simulations have been run including a number of effects—both nominal and off-nominal—such as hohlraum radiation asymmetries, surface roughness, the capsule support tent, and hot electron pre-heat. Selected three-dimensional simulations have also been run to assess the validity of the 2D axisymmetric approximation. As a composite, these simulations represent the current state of understanding of NIF high foot implosion performance using the best and most detailed computational model available. While the most detailed simulations show approximate agreement with the experimental data, it is evident that the model remains incomplete and further refinements are needed. Nevertheless, avenues for improved performance are clearly indicated.

  19. FTIR Analysis of Flowing Afterglow from a High-Frequency Spark Discharge

    Science.gov (United States)

    White, Allen; Hieftje, Gary M.; Ray, Steve; Pfeuffer, Kevin

    2014-06-01

    Plasmas are often used as ionization sources for ambient mass spectrometry (AMS). Here, the flowing afterglow of a novel high-energy spark discharge system, operated in nitrogen at high repetition rates, is investigated as a source for AMS. The spark discharge here is the same as that of an automobile ignition circuit.Combustion in automobile engines is initiated by a spark ignition system that is designed to deliver short-duration,high-voltage sparks to multiple engine cylinders. The arrangement utilized in this study is a modified discharge configuration designed to produce similarly short-duration, high-voltage discharges. It consists of an automotive ignition coil that is activated by a spark initiation circuit that discharges in turn into a cell with neutral gas input flow and ultimately into the collection orifice of a mass spectrometer. The discharge voltage is approximately 40kV at 800 Hz. High-frequency spark discharges in a nitrogen flow produce reagent ions such as NO+. In order to better evaluate the effectiveness of the discharge in producing reagent ions, an FTIR is utilized to measure IR active species such as nitric oxide, hydroxide, ozone, and water in the afterglow of the spark discharge during variation of discharge parameters. Time-resolved IR emission spectra provide additional insight into the reagent ion production mechanisms.

  20. Modelling the ignition process on the injection jet for Diesel engine combustion; Modellierung des Zuendvorgangs am Einspritzstrahl bei dieselmotorischer Verbrennung

    Energy Technology Data Exchange (ETDEWEB)

    Pitsch, H.; Mueller, U.C.; Peters, N.

    1995-12-31

    A simplified chemical model is developed to describe Diesel engine self-ignition processes. It is assumed that the ignition of Diesel fuel can be described by the single component fuel n-heptane. Starting from a detailed reaction mechanism for n-heptane with about 1000 element reactions and 168 chemical substances, a starting mechanism with 81 element reactions and 37 chemical substances is produced by a reaction flow analysis which can describe ignition processes in conditions relevant for Diesel engines. The introduction of steady state assumptions for quickly consumed intermediate species leads to a reduced mechanism with 14 global reaction steps. In order to prove the validity of these reduced mechanisms, calculated ignition delay times are compared with surge wave tube experiments for different temperatures, pressures and fuel ratios. Finally, one dimensional calculations of ignition processes in the mixing space for pressures and temperatures relevant for engines are introduced. From these, the effect of the scalar dissipation rate which describes the extent of diffusion flames on the ignition delay times, is discussed. An approximation formula for the ignition delay times as a function of the dissipation rate is derived. (orig.) [Deutsch] Zur Beschreibung dieselmotorischer Selbstzuendprozesse wird ein vereinfachtes chemisches Modell entwickelt. Dazu wird angenommen, dass die Zuendung von Dieselkraftstoffen durch den Einkomponentenkraftstoff n-Heptan beschrieben werden kann. Ausgehend von einem detaillierten Reaktionsmechanismus fuer n-Heptan mit ungefaehr 1000 Elementarreaktionen und 168 chemischen Spezies wird mittels einer Reaktionsflussanalyse ein Startmechanismus mit 81 Elementarreaktionen und 37 chemischen Spezies erstellt, der in der Lage ist, Zuendprozesse unter dieselmotorisch relevanten Bedingungen zu beschreiben. Die Einfuehrung von Stationaritaetsannahmen fuer schnell verbrauchte Zwischenspezies fuehrt auf einen reduzierten Mechanismus mit 14

  1. Modeling the breakdown and glow phases during ignition of HID lamps

    Energy Technology Data Exchange (ETDEWEB)

    Liland, K.B.; Peres, I.; Pitchford, L.C.; Boeuf, J.P. [Univ. Paul Sabatier, Toulouse (France)

    1996-12-31

    HID lamps are often ignited by one or more short, high voltage pulses (trigger pulses) superimposed on the low frequency, generator voltage. The authors have developed a self-consistent, fluid model of transient glow discharges to study the breakdown and glow phases in HID lamps from the time of the application of the trigger pulse(s) to the time when there is a fully-developed, quasi-steady state glow discharge. The transition to the thermionic arc is not considered here. Using this model they have investigated the influence of the height, width and number of trigger pulses on the generator voltage required to achieve a steady-state glow discharge. The model used is one-dimensional, and the fundamental variables are the charged particle densities and the potential as functions of distance between the electrodes and time. The minimum voltage needed to initiate a glow discharge, V{sub g}, decreases with increasing current during the trigger pulse and reaches a minimum which is a few volts above the steady-state glow voltage. Results in discharges in argon and argon/mercury mixtures will be presented showing the dependence of V{sub g} on the trigger pulse and on other discharge conditions (gas mixture, external circuit, ...). The calculated, steady-state glow current-voltage characteristic will also be presented.

  2. Ignition target design for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Haan, S.W.; Pollaine, S.M.; Lindl, J.D. [Los Alamos National Laboratory, NM (United States)] [and others

    1996-06-01

    The goal of inertial confinement fusion (ICF) is to produce significant thermonuclear burn from a target driven with a laser or ion beam. To achieve that goal, the national ICF Program has proposed a laser capable of producing ignition and intermediate gain. The facility is called the National Ignition Facility (NIF). This article describes ignition targets designed for the NIF and their modeling. Although the baseline NIF target design, described herein, is indirect drive, the facility will also be capable of doing direct-drive ignition targets - currently being developed at the University of Rochester.

  3. Shock Tube Ignition Delay Data Affected by Localized Ignition Phenomena

    KAUST Repository

    Javed, Tamour

    2016-12-29

    Shock tubes have conventionally been used for measuring high-temperature ignition delay times ~ O(1 ms). In the last decade or so, the operating regime of shock tubes has been extended to lower temperatures by accessing longer observation times. Such measurements may potentially be affected by some non-ideal phenomena. The purpose of this work is to measure long ignition delay times for fuels exhibiting negative temperature coefficient (NTC) and to assess the impact of shock tube non-idealities on ignition delay data. Ignition delay times of n-heptane and n-hexane were measured over the temperature range of 650 – 1250 K and pressures near 1.5 atm. Driver gas tailoring and long length of shock tube driver section were utilized to measure ignition delay times as long as 32 ms. Measured ignition delay times agree with chemical kinetic models at high (> 1100 K) and low (< 700 K) temperatures. In the intermediate temperature range (700 – 1100 K), however, significant discrepancies are observed between the measurements and homogeneous ignition delay simulations. It is postulated, based on experimental observations, that localized ignition kernels could affect the ignition delay times at the intermediate temperatures, which lead to compression (and heating) of the bulk gas and result in expediting the overall ignition event. The postulate is validated through simple representative computational fluid dynamic simulations of post-shock gas mixtures which exhibit ignition advancement via a hot spot. The results of the current work show that ignition delay times measured by shock tubes may be affected by non-ideal phenomena for certain conditions of temperature, pressure and fuel reactivity. Care must, therefore, be exercised in using such data for chemical kinetic model development and validation.

  4. Life and death of a cardiac calcium spark.

    Science.gov (United States)

    Stern, Michael D; Ríos, Eduardo; Maltsev, Victor A

    2013-09-01

    Calcium sparks in cardiac myocytes are brief, localized calcium releases from the sarcoplasmic reticulum (SR) believed to be caused by locally regenerative calcium-induced calcium release (CICR) via couplons, clusters of ryanodine receptors (RyRs). How such regeneration is terminated is uncertain. We performed numerical simulations of an idealized stochastic model of spark production, assuming a RyR gating scheme with only two states (open and closed). Local depletion of calcium in the SR was inevitable during a spark, and this could terminate sparks by interrupting CICR, with or without assumed modulation of RyR gating by SR lumenal calcium. Spark termination by local SR depletion was not robust: under some conditions, sparks could be greatly and variably prolonged, terminating by stochastic attrition-a phenomenon we dub "spark metastability." Spark fluorescence rise time was not a good surrogate for the duration of calcium release. Using a highly simplified, deterministic model of the dynamics of a couplon, we show that spark metastability depends on the kinetic relationship of RyR gating and junctional SR refilling rates. The conditions for spark metastability resemble those produced by known mutations of RyR2 and CASQ2 that cause life-threatening triggered arrhythmias, and spark metastability may be mitigated by altering the kinetics of the RyR in a manner similar to the effects of drugs known to prevent those arrhythmias. The model was unable to explain the distributions of spark amplitudes and rise times seen in chemically skinned cat atrial myocytes, suggesting that such sparks may be more complex events involving heterogeneity of couplons or local propagation among sub-clusters of RyRs.

  5. Interpreting Shock Tube Ignition Data

    Science.gov (United States)

    2003-10-01

    times only for high concentrations (of order 1% fuel or greater). The requirements of engine (IC, HCCI , CI and SI) modelers also present a different...Paper 03F-61 Interpreting Shock Tube Ignition Data D. F. Davidson and R. K. Hanson Mechanical Engineering ... Engineering Department Stanford University, Stanford CA 94305 Abstract Chemical kinetic modelers make extensive use of shock tube ignition data

  6. Mathematical Modelling of Nonstationary Physico Chemical Processes in Large Sized SPRM Pyrotechnical Ignition System

    Directory of Open Access Journals (Sweden)

    Alexey M. Lipanov

    1997-10-01

    Full Text Available In this paper, the laws of the unstable wave processes accompanying the combustion abnormal mode in the large-sized solid propellant rocket motor {SPRM pyrotechnical ignition system {IS are investigated by numerical method. The IS contains the main {cylindrical channel (MC having uniform perforation over the lateral surface, The left MC boundary is blocked and the right boundary is uniformly perforated. The whole perforation is hermetically sealed from outside. The additional {cylindrical channel {AC {an initial impulse amplifier with uniform perforation over the lateral surface is installed into the MC cavity, coaxially to MC. The right AC boundary is blocked, and the time-varying high-temperature gas flow, containing incandescent 'particles is supplied from initiator, equipped with a fast burning compound, through AC left perforated boundary. To imitate the exploitation conditions, the IS is placed in cylindrical imitation chamber {imitative SPRM. In a number of cases, before the beginning of the IS operation, a situation can be realised when the pelletised solid propellant {PSP mass is non-uniformly distributed along the IS AC length, and the greater part of the AC lateral perforation is blocked by the PSP inserted in the IS MC. Under these conditions, the effect of abnormal strengthening of the pressure waves at the AC boundaries is possible. For describing the abnormal nonstationary physico-chemical processes, a mathematical model is developed. For the check-up of this complex model, the numerical calculation results have been compared with the results of the fire stand tests for the regular IS and the engine. The numerical analysis of the unstable wave process development in the AC has shown that the rise of the pressure with an ever increasing amplitude is realised at the moment, when a shock wave reflects alternately, on the left and on the right AC boundaries. The effect of the pressure waves' abnormal strengthening can result in the

  7. Low-Load Limit in a Diesel-Ignited Gas Engine

    Directory of Open Access Journals (Sweden)

    Richard Hutter

    2017-09-01

    Full Text Available The lean-burn capability of the Diesel-ignited gas engine combined with its potential for high efficiency and low CO 2 emissions makes this engine concept one of the most promising alternative fuel converters for passenger cars. Instead of using a spark plug, the ignition relies on the compression-ignited Diesel fuel providing ignition centers for the homogeneous air-gas mixture. In this study the amount of Diesel is reduced to the minimum amount required for the desired ignition. The low-load operation of such an engine is known to be challenging, as hydrocarbon (HC emissions rise. The objective of this study is to develop optimal low-load operation strategies for the input variables equivalence ratio and exhaust gas recirculation (EGR rate. A physical engine model helps to investigate three important limitations, namely maximum acceptable HC emissions, minimal CO 2 reduction, and minimal exhaust gas temperature. An important finding is the fact that the high HC emissions under low-load and lean conditions are a consequence of the inability to raise the gas equivalence ratio resulting in a poor flame propagation. The simulations on the various low-load strategies reveal the conflicting demand of lean combustion with low CO 2 emissions and stoichiometric operation with low HC emissions, as well as the minimal feasible dual-fuel load of 3.2 bar brake mean effective pressure.

  8. STUDENT AWARD FINALIST: Oxygen Pathways in Streamer Discharge for Transient Plasma Ignition

    Science.gov (United States)

    Pendleton, S. J.; Bowman, S.; Singleton, D.; Watrous, J.; Carter, C.; Lempert, W.; Gundersen, M. A.

    2011-10-01

    The use of streamers for the ignition of fuels, also known as transient plasma ignition (TPI), has been shown in a variety of engines to improve combustion through decreased ignition delay, increased lean burn capability and increased energy release relative to conventional spark ignition. The mechanisms behind these improvements, however, remain poorly understood. Temperature measurements by optical emission spectroscopy demonstrate that ignition by TPI is a nonthermal process, and thus is almost entirely dependent on the production and presence of electron impact-created active species in the discharge afterglow. Of particular interest are active oxygen species due to their relatively long lifetimes at high pressures and the pivotal role they play in combustion reactions. In order to elucidate the oxygen pathways, here we report the investigation of the temporal evolution of the populations of atomic oxygen and ozone by use of two-photon absorption laser induced fluorescence (TALIF) and UV absorption, respectively. Experimental results are presented and compared to kinetic modeling of the streamers. Future experiments are proposed to better understand the physics behind TPI. Supported by NSF, AFOSR, NumerEx-ONR, AFRL-WPAFB.

  9. Ignition and growth reactive flow modeling of recent HMX/TATB detonation experiments

    Science.gov (United States)

    Tarver, Craig M.

    2017-01-01

    Two experimental studies in which faster HMX detonation waves produced oblique detonation waves in adjoining slower detonating TATB charges were modeled using the Ignition and Growth (I&G) reactive flow detonation model parameters for PBX 9501 (95% HMX / 2.5% Estane / 2.5% BDNPA/F) and PBX 9502 (95% TATB / 5% Kel-F binder). Matignon et al. used X1 explosive (96% HMX / 4% binder) to drive an oblique detonation wave into an attached charge of T2 explosive (97% TATB / 3% binder). The flow angles were measured in the T2 shock initiation region and in steady T2 detonation. Anderson et al. used detonating PBX 9501 slabs of various thicknesses ranging from 0.56 mm to 2.5 mm to create oblique detonation waves in 8 mm thick slabs of PBX 9502. Several diagnostics were employed to: photograph the waves; measure detonation velocities and flow angles; and determine the output of the PBX 9501 slabs, the PBX 9502 slabs, and the "initiation regions" using LiF windows and PDV probes.

  10. A superburst candidate in EXO 1745--248 as a challenge to thermonuclear ignition models

    CERN Document Server

    Altamirano, D; Cumming, A; Sivakoff, G R; Heinke, C O; Wijnands, R; Degenaar, N; Homan, J; Pooley, D

    2012-01-01

    We report on Chandra, RXTE, Swift/BAT and MAXI observations of a ~1 day X-ray flare and subsequent outburst of a transient X-ray source observed in October-November 2011 in the globular cluster Terzan 5. We show that the source is the same as the transient that was active in 2000, i.e., the neutron star low-mass X-ray binary EXO 1745-248. For the X-ray flare we estimate a 6-11 hr exponential decay time and a radiated energy of 2-9 x 10^42 erg. These properties, together with strong evidence of decreasing blackbody temperature during the flare decay, are fully consistent with what is expected for a thermonuclear superburst. We use the most recent superburst models and estimate an ignition column depth of ~10^12 g cm^-2 and an energy release between 0.1-2 x 10^18 erg g^-1, also consistent with expected superburst values. We conclude therefore that the flare was most probably a superburst. We discuss our results in the context of theoretical models and find that even when assuming a few days of low level accreti...

  11. Mean Value Modelling of a Turbocharged SI Engine

    DEFF Research Database (Denmark)

    Müller, Martin; Hendricks, Elbert; Sorenson, Spencer C.

    1998-01-01

    An important paradigm for the modelling of naturallly aspirated (NA) spark ignition (SI) engines for control purposes is the Mean Value Engine Model (MVEM). Such models have a time resolution which is just sufficient to capture the main details of the dynamic performance of NA SI engines but not ...

  12. Evaporation and ignition of droplets in combustion chambers modeling and simulation

    Science.gov (United States)

    Betelin, V. B.; Smirnov, N. N.; Nikitin, V. F.; Dushin, V. R.; Kushnirenko, A. G.; Nerchenko, V. A.

    2012-01-01

    Computer simulation of liquid fuel jet injection into heated atmosphere of combustion chamber, mixture formation, ignition and combustion need adequate modeling of evaporation, which is extremely important for the curved surfaces in the presence of strong heat and mass diffusion fluxes. Combustion of most widely spread hydrocarbon fuels takes place in a gas-phase regime. Thus, evaporation of fuel from the surface of droplets turns to be one of the limiting factors of the process as well. The problems of fuel droplets atomization, evaporation being the key factors for heterogeneous reacting mixtures, the non-equilibrium effects in droplets atomization and phase transitions will be taken into account in describing thermal and mechanical interaction of droplets with streaming flows. In the present paper processes of non-equilibrium evaporation of small droplets will be discussed. As it was shown before, accounting for non-equilibrium effects in evaporation for many types of widely used liquids is crucial for droplet diameters less than 100 μm, while the surface tension effects essentially manifest only for droplets below 0.1 μm. Investigating the behavior of individual droplets in a heated air flow allowed to distinguish two scenarios for droplet heating and evaporation. Small droplets undergo successively heating, then cooling due to heat losses for evaporation, and then rapid heating till the end of their lifetime. Larger droplets could directly be heated up to a critical temperature and then evaporate rapidly. Droplet atomization interferes the heating, evaporation and combustion scenario. The scenario of fuel spray injection and self-ignition in a heated air inside combustion chamber has three characteristic stages. At first stage of jet injection droplets evaporate very rapidly thus cooling the gas at injection point, the liquid jet is very short and changes for a vapor jet. At second stage liquid jet is becoming longer, because evaporation rate decreases due

  13. Relationship between exploding bridgewire and spark initiation of low density PETN

    Science.gov (United States)

    Lee, Elizabeth; Drake, Rod

    2017-01-01

    Recent work has shown that the energy delivered after bridgewire burst affects the function time of an EBW detonator. The spark which is formed post bridgewire burst is the means by which the remaining fireset energy contributes to the reaction. Therefore, by studying the characteristics of spark-gap detonators, insight into the contribution of spark initiation to the functioning of EBW detonators may be achieved. Spark initiation of low density explosives consists of: (i) spark formation, (ii) spark interaction with the bed, and (iii) ignition and growth of reaction. Experiments were performed in which an inert simulant was used to study the formation and propagation of sparks as a function of spark energy. The effect of the spark on inert porous beds was studied over a limited delivered energy range. The disruption of the bed was found to be dependent on the energy delivered. The effect of spark initiation on a low density PETN bed was then examined, the relationship between delivered energy and function time was found to be the same as for EBW detonators.

  14. Effects of alpha stopping power modelling on the ignition threshold in a directly-driven inertial confinement fusion capsule

    Science.gov (United States)

    Temporal, Mauro; Canaud, Benoit; Cayzac, Witold; Ramis, Rafael; Singleton, Robert L.

    2017-05-01

    The alpha-particle energy deposition mechanism modifies the ignition conditions of the thermonuclear Deuterium-Tritium fusion reactions, and constitutes a key issue in achieving high gain in Inertial Confinement Fusion implosions. One-dimensional hydrodynamic calculations have been performed with the code Multi-IFE [R. Ramis, J. Meyer-ter-Vehn, Comput. Phys. Commun. 203, 226 (2016)] to simulate the implosion of a capsule directly irradiated by a laser beam. The diffusion approximation for the alpha energy deposition has been used to optimize three laser profiles corresponding to different implosion velocities. A Monte-Carlo package has been included in Multi-IFE to calculate the alpha energy transport, and in this case the energy deposition uses both the LP [C.K. Li, R.D. Petrasso, Phys. Rev. Lett. 70, 3059 (1993)] and the BPS [L.S. Brown, D.L. Preston, R.L. Singleton Jr., Phys. Rep. 410, 237 (2005)] stopping power models. Homothetic transformations that maintain a constant implosion velocity have been used to map out the transition region between marginally-igniting and high-gain configurations. The results provided by the two models have been compared and it is found that - close to the ignition threshold - in order to produce the same fusion energy, the calculations performed with the BPS model require about 10% more invested energy with respect to the LP model.

  15. Pulsating reverse detonation models of Type Ia supernovae. I: Detonation ignition

    CERN Document Server

    Bravo, Eduardo

    2009-01-01

    Observational evidences point to a common explosion mechanism of Type Ia supernovae based on a delayed detonation of a white dwarf. Although several scenarios have been proposed and explored by means of one, two, and three-dimensional simulations, the key point still is the understanding of the conditions under which a stable detonation can form in a destabilized white dwarf. One of the possibilities that have been invoked is that an inefficient deflagration leads to the pulsation of a Chandrasekhar-mass white dwarf, followed by formation of an accretion shock around a carbon-oxygen rich core. The accretion shock confines the core and transforms kinetic energy from the collapsing halo into thermal energy of the core, until an inward moving detonation is formed. This chain of events has been termed Pulsating Reverse Detonation (PRD). In this work we explore the robustness of the detonation ignition for different PRD models characterized by the amount of mass burned during the deflagration phase, M_defl. The ev...

  16. Ignition and growth modeling of detonation reaction zone experiments on single crystals of PETN and HMX

    Science.gov (United States)

    White, Bradley W.; Tarver, Craig M.

    2017-01-01

    It has long been known that detonating single crystals of solid explosives have much larger failure diameters than those of heterogeneous charges of the same explosive pressed or cast to 98 - 99% theoretical maximum density (TMD). In 1957, Holland et al. demonstrated that PETN single crystals have failure diameters of about 8 mm, whereas heterogeneous PETN charges have failure diameters of less than 0.5 mm. Recently, Fedorov et al. quantitatively determined nanosecond time resolved detonation reaction zone profiles of single crystals of PETN and HMX by measuring the interface particle velocity histories of the detonating crystals and LiF windows using a PDV system. The measured reaction zone time durations for PETN and HMX single crystal detonations were approximately 100 and 260 nanoseconds, respectively. These experiments provided the necessary data to develop Ignition and Growth (I&G) reactive flow model parameters for the single crystal detonation reaction zones. Using these parameters, the calculated unconfined failure diameter of a PETN single crystal was 7.5 +/- 0.5 mm, close to the 8 mm experimental value. The calculated failure diameter of an unconfined HMX single crystal was 15 +/- 1 mm. The unconfined failure diameter of an HMX single crystal has not yet been determined precisely, but Fedorov et al. detonated 14 mm diameter crystals confined by detonating a HMX-based plastic bonded explosive (PBX) without initially overdriving the HMX crystals.

  17. Modeling of heat release and emissions from droplet combustion of multi component fuels in compression ignition engines

    OpenAIRE

    Ivarsson, Anders; Schramm, Jesper

    2010-01-01

    This PhD dissertation was carried out at the Technical University of Denmark in Department of Mechanical Engineering and supervised by Associate Professor Jesper Schramm. The PhD project was funded by the Technical University of Denmark. Demands on reducing the fuel consumption and harmful emissions from the compression ignition engines (CI engines or diesel engines) are continuously increased. To comply with this, better modeling tools for the diesel combustion process are desired from the e...

  18. An investigation of using various diesel-type fuels in homogeneous charge compression ignition engines and their effects on operational and controlling issues

    Energy Technology Data Exchange (ETDEWEB)

    Milovanovic, N.; Chen, R. [Loughborough Univ., Aeronautical and Automotive Dept., Loughborough (United Kingdom); Dowden, R. [Swansea Inst. of Higher Education, School of Automotive Engineering, Swansea (United Kingdom); Turner, J. [Lotus Engineering, Powertrain Research Dept., Hethel (United Kingdom)

    2004-12-01

    Homogeneous charge compression ignition (HCCI) engines appear to be a future alternative to diesel and spark-ignited engines. The HCCI engine has the potential to deliver high efficiency and very low NO{sub x} and particulate matter emissions. There are, however, problems with the control of ignition and heat release range over the entire load and speed range which limits the practical application of this technology. The aim of this paper is to analyse the use of different types of diesel fuels in an HCCI engine and hence to find the most suitable with respect to operational and control issues. The single-zone combustion model with convective heat transfer loss is used to simulate the HCCI engine environment. n-Heptane, dimethyl ether and bio-diesel (methyl butanoate and methyl formate) fuels are investigated. Methyl butanoate and methyl formate represent surrogates of heavy and light bio-diesel fuel respectively. The effects of different engine parameters such as equivalence ratio and engine speed on the ignition timing are investigated. The use of internal exhaust gas recirculation is investigated as a potential strategy for controlling the ignition timing. The results indicate that the use of bio-diesel fuels will result in lower sensitivity of ignition timing to changes in operational parameters and in a better control of the ignition process when compared with the use of n-heptane and dimethyl ether. (Author)

  19. Mars Spark Source Prototype

    Science.gov (United States)

    Eichenberg, Dennis J.; Lindamood, Glenn R.; Weiland, Karen J.; VanderWal, Randall L.

    1999-01-01

    The Mars Spark Source Prototype (MSSP) hardware has been developed as part of a proof of concept system for the detection of trace metals such as lead, cadmium, and arsenic in Martian dusts and soils. A spark discharge produces plasma from a soil sample and detectors measure the optical emission from metals in the plasma that will allow their identification and quantification. Trace metal measurements are vital for the assessment of the potential toxicity of the Martian environment for human exploration. The current method of X-ray fluorescence can yield concentrations only of major species. Other instruments are incompatible with the volume, weight, and power constraints for a Mars mission. The instrument will be developed primarily for use in the Martian environment, but would be adaptable for terrestrial use in environmental monitoring. This paper describes the Mars Spark Source Prototype hardware, the results of the characterization tests, and future plans for hardware development.

  20. Numerical Simulations of Hollow Cone Injection and Gasoline Compression Ignition Combustion With Naphtha Fuels

    KAUST Repository

    Badra, Jihad A.

    2016-01-11

    Gasoline compression ignition (GCI), also known as partially premixed compression ignition (PPCI) and gasoline direct injection compression ignition (GDICI), engines have been considered an attractive alternative to traditional spark ignition engines. Lean burn combustion with the direct injection of fuel eliminates throttle losses for higher thermodynamic efficiencies, and the precise control of the mixture compositions allows better emission performance such as NOx and particulate matter (PM). Recently, low octane gasoline fuel has been identified as a viable option for the GCI engine applications due to its longer ignition delay characteristics compared to diesel and lighter evaporation compared to gasoline fuel [1]. The feasibility of such a concept has been demonstrated by experimental investigations at Saudi Aramco [1, 2]. The present study aims to develop predictive capabilities for low octane gasoline fuel compression ignition engines with accurate characterization of the spray dynamics and combustion processes. Full three-dimensional simulations were conducted using CONVERGE as a basic modeling framework, using Reynolds-averaged Navier-Stokes (RANS) turbulent mixing models. An outwardly opening hollow-cone spray injector was characterized and validated against existing and new experimental data. An emphasis was made on the spray penetration characteristics. Various spray breakup and collision models have been tested and compared with the experimental data. An optimum combination has been identified and applied in the combusting GCI simulations. Linear instability sheet atomization (LISA) breakup model and modified Kelvin-Helmholtz and Rayleigh-Taylor (KH-RT) break models proved to work the best for the investigated injector. Comparisons between various existing spray models and a parametric study have been carried out to study the effects of various spray parameters. The fuel effects have been tested by using three different primary reference fuel (PRF

  1. Impact of Fast Ignition on Laser Fusion Energy Development

    Science.gov (United States)

    Mirna, Kunioki

    2016-10-01

    Reviewed are the early history of Japanese laser fusion research and the recent achievement of fast ignition research at Institute of Laser Engineering (ILE), Osaka University. After the achievement of high density compression at Osaka University, LLE of University Rochester, and LLNL, the critical issue of Inertial Fusion Energy (IFE) research became the formation of hot spark in a compressed plasma. In this lecture, the history of the fast ignition research will be reviewed and future prospects are presented.

  2. Numerical modeling on homogeneous charge compression ignition combustion engine fueled by diesel-ethanol blends

    Directory of Open Access Journals (Sweden)

    Hanafi H.

    2016-01-01

    Full Text Available This paper investigates the performance and emission characteristics of HCCI engines fueled with oxygenated fuels (ethanol blend. A modeling study was conducted to investigate the impact of ethanol addition on the performance, combustion and emission characteristics of a Homogeneous Charge Compression Ignition (HCCI engine fueled by diesel. One dimensional simulation was conducted using the renowned commercial software for diesel and its blend fuels with 5% (E5 and 10% ethanol (E10 (in vol. under full load condition at variable engine speed ranging from 1000 to 2750 rpm with 250 rpm increment. The model was then validated with other researcher’s experimental result. Model consists of intake and exhaust systems, cylinder, head, valves and port geometries. Performance tests were conducted for volumetric efficiency, brake engine torque, brake power, brake mean effective pressure, brake specific fuel consumption, and brake thermal efficiency, while exhaust emissions were analyzed for carbon monoxide (CO and unburned hydrocarbons (HC. The results showed that blending diesel with ethanol increases the volumetric efficiency, brake specific fuel consumption and brake thermal efficiency, while it decreases brake engine torque, brake power and brake mean effective pressure. In term of emission characteristics, the CO emissions concentrations in the engine exhaust decrease significantly with ethanol as additive. But for HC emission, its concentration increase when apply in high engine speed. In conclusion, using Ethanol as fuel additive blend with Diesel operating in HCCI shows a good result in term of performance and emission in low speed but not recommended to use in high speed engine. Ethanol-diesel blends need to researched more to make it commercially useable.

  3. Spark Plasma Sintering of Aluminum-Magnesium-Matrix Composites with Boron Carbide and Tungsten Nano-powder Inclusions: Modeling and Experimentation

    Science.gov (United States)

    Dvilis, E. S.; Khasanov, O. L.; Gulbin, V. N.; Petyukevich, M. S.; Khasanov, A. O.; Olevsky, E. A.

    2016-03-01

    Spark-plasma sintering (SPS) is used to fabricate fully-dense metal-matrix (Al/Mg) composites containing hard ceramic (boron carbide) and refractory metal (tungsten) inclusions. The study objectives include the modeling (and its experimental verification) of the process of the consolidation of the composites consisted of aluminum-magnesium alloy AMg6 (65 wt.%), B4C powder (15 wt.%), and W nano-powder (20 wt.%), as well as the optimization of the composite content and of the SPS conditions to achieve higher density. Discrete element modeling of the composite particles packing based on the particle size distribution functions of real powders is utilized for the determination of the powder compositions rendering maximum mixture packing densities. Two models: a power-law creep model of the high temperature deformation of powder materials, and an empirical logarithmic pressure-temperature-relative density relationship are successfully applied for the description of the densification of the aluminum-magnesium metal matrix powder composite subjected to spark-plasma sintering. The elastoplastic properties of the sintered composite samples are assessed by nanoindentation.

  4. The lean burn direct injection jet ignition gas engine

    Energy Technology Data Exchange (ETDEWEB)

    Boretti, Alberto A.; Watson, Harry C. [School of Science and Engineering, University of Ballarat, PO Box 663, Ballarat, Victoria 3353 (Australia)

    2009-09-15

    This paper presents a new in-cylinder mixture preparation and ignition system for various fuels including hydrogen, methane and propane. The system comprises a centrally located direct injection (DI) injector and a jet ignition (JI) device for combustion of the main chamber (MC) mixture. The fuel is injected in the MC with a new generation, fast actuating, high pressure, high flow rate DI injector capable of injection shaping and multiple events. This injector produces a bulk, lean stratified mixture. The JI system uses a second DI injector to inject a small amount of fuel in a small pre-chamber (PC). In the spark ignition (SI) version, a spark plug then ignites a slightly rich mixture. In the auto ignition version, a DI injector injects a small amount of higher pressure fuel in the small PC having a hot glow plug (GP) surface, and the fuel auto ignites in the hot air or when in contact with the hot surface. Either way the MC mixture is then bulk ignited through multiple jets of hot reacting gases. Bulk ignition of the lean, jet controlled, stratified MC mixture resulting from coupling DI with JI makes it possible to burn MC mixtures with fuel to air equivalence ratios reducing almost to zero for a throttle-less control of load diesel-like and high efficiencies over almost the full range of loads. (author)

  5. 40 CFR 265.17 - General requirements for ignitable, reactive, or incompatible wastes.

    Science.gov (United States)

    2010-07-01

    ... heat or pressure, fire or explosion, or violent reaction; (2) Produce uncontrolled toxic mists, fumes..., smoking, cutting and welding, hot surfaces, frictional heat, sparks (static, electrical, or mechanical), spontaneous ignition (e.g., from heat-producing chemical reactions), and radiant heat. While ignitable...

  6. Analysis of Electromagnetic Radiation by Simulating the Motorcycle Ignition System%摩托车点火系统的电磁辐射仿真

    Institute of Scientific and Technical Information of China (English)

    赵曌; 伍小龙; 徐中明; 贺岩松; 刘青松

    2013-01-01

    建立了摩托车车体简化三维模型以及点火系统高压部分的三维模型,并以点火系统火花塞击穿时的瞬变电压为激励源,利用有限积分法对点火系统产生的电磁辐射进行仿真,通过模拟3 m测试法得到系统电磁辐射电场.探讨了更改点火系统中火花塞帽、高压导线、火花塞参数对系统产生的电磁辐射强度的影响.%3 D models of simplified motorcycle along with the high-voltage compartment of its ignition system are established.Setting transient voltage appeared during the spark plug ignition is used as the excitation source.Finite Integration Technique (simplified as FIT) is utilized to simulate electromagnetic radiation of the ignition system,and the radiation of the whole system is acquired by emulating testing methods mentioned in GB14023.Additionally,various electromagnetic radiation of system results from the different type of spark plug,spark plug cap and the high-voltage coil have been carefully researched.

  7. Progress in detailed modelling of low foot and high foot implosion experiments on the National Ignition Facility

    Science.gov (United States)

    Clark, D. S.; Weber, C. R.; Eder, D. C.; Haan, S. W.; Hammel, B. A.; Hinkel, D. E.; Jones, O. S.; Kritcher, A. L.; Marinak, M. M.; Milovich, J. L.; Patel, P. K.; Robey, H. F.; Salmonson, J. D.; Sepke, S. M.

    2016-05-01

    Several dozen high convergence inertial confinement fusion ignition experiments have now been completed on the National Ignition Facility (NIF). These include both “low foot” experiments from the National Ignition Campaign (NIC) and more recent “high foot” experiments. At the time of the NIC, there were large discrepancies between simulated implosion performance and experimental data. In particular, simulations over predicted neutron yields by up to an order of magnitude, and some experiments showed clear evidence of mixing of ablator material deep into the hot spot that could not be explained at the time. While the agreement between data and simulation improved for high foot implosion experiments, discrepancies nevertheless remain. This paper describes the state of detailed modelling of both low foot and high foot implosions using 1-D, 2-D, and 3-D radiation hydrodynamics simulations with HYDRA. The simulations include a range of effects, in particular, the impact of the plastic membrane used to support the capsule in the hohlraum, as well as low-mode radiation asymmetries tuned to match radiography measurements. The same simulation methodology is applied to low foot NIC implosion experiments and high foot implosions, and shows a qualitatively similar level of agreement for both types of implosions. While comparison with the experimental data remains imperfect, a reasonable level of agreement is emerging and shows a growing understanding of the high-convergence implosions being performed on NIF.

  8. Ignition and flame-growth modeling on realistic building and landscape objects in changing environments

    Science.gov (United States)

    Mark A. Dietenberger

    2010-01-01

    Effective mitigation of external fires on structures can be achieved flexibly, economically, and aesthetically by (1) preventing large-area ignition on structures by avoiding close proximity of burning vegetation; and (2) stopping flame travel from firebrands landing on combustible building objects. Using bench-scale and mid-scale fire tests to obtain flammability...

  9. Multi scale modeling of ignition and combustion of micro and nano aluminum particles

    Science.gov (United States)

    Puri, Puneesh

    With renewed interest in nano scale energetic materials like aluminum, many fundamental issues concerning the ignition and combustion characteristics at nano scales, remain to be clarified. The overall aim of the current study is the establishment of a unified theory accommodating the various processes and mechanisms involved in the combustion and ignition of aluminum particles at micro and nano scales. A comprehensive review on the ignition and combustion of aluminum particles at multi scales was first performed identifying various processes and mechanisms involved. Research focus was also placed on the establishment of a Molecular Dynamics (MD) simulation tool to investigate the characteristics of nano-particulate aluminum through three major studies. The general computational framework involved parallelized preprocessing, post-processing and main code with capability to simulate different ensembles using appropriate algorithms. Size dependence of melting temperature of pure aluminum particles was investigated in the first study. Phenomena like dynamic coexistence of solid and liquid phase and effect of surface charges on melting were explored. The second study involved the study of effect of defects in the form of voids on melting of bulk and particulate phase aluminum. The third MD study was used to analyze the thermo-mechanical behavior of nano-sized aluminum particles with total diameter of 5-10 nm and oxide thickness of 1-2.5 nm. The ensuing solid-solid and solid-liquid phase changes in the core and shell, stresses developed within the shell, and the diffusion of aluminum cations in the oxide layer, were explored in depth for amorphous and crystalline oxide layers. In the limiting case, the condition for pyrophoricity/explosivity of nano-particulate aluminum was analyzed and modified. The size dependence of thermodynamic properties at nano scales were considered and incorporated into the existing theories developed for micro and larger scales. Finally, a

  10. Numerical Simulations of Hollow-Cone Injection and Gasoline Compression Ignition Combustion With Naphtha Fuels

    KAUST Repository

    Badra, Jihad A.

    2016-01-29

    Gasoline compression ignition (GCI), also known as partially premixed compression ignition (PPCI) and gasoline direct injection compression ignition (GDICI), engines have been considered an attractive alternative to traditional spark ignition (SI) engines. Lean-burn combustion with the direct injection of fuel eliminates throttle losses for higher thermodynamic efficiencies, and the precise control of the mixture compositions allows better emission performance such as NOx and particulate matter (PM). Recently, low octane gasoline fuel has been identified as a viable option for the GCI engine applications due to its longer ignition delay characteristics compared to diesel and lighter evaporation compared to gasoline fuel (Chang et al., 2012, "Enabling High Efficiency Direct Injection Engine With Naphtha Fuel Through Partially Premixed Charge Compression Ignition Combustion," SAE Technical Paper No. 2012-01-0677). The feasibility of such a concept has been demonstrated by experimental investigations at Saudi Aramco (Chang et al., 2012, "Enabling High Efficiency Direct Injection Engine With Naphtha Fuel Through Partially Premixed Charge Compression Ignition Combustion," SAE Technical Paper No. 2012-01-0677; Chang et al., 2013, "Fuel Economy Potential of Partially Premixed Compression Ignition (PPCI) Combustion With Naphtha Fuel," SAE Technical Paper No. 2013-01-2701). The present study aims to develop predictive capabilities for low octane gasoline fuel compression ignition (CI) engines with accurate characterization of the spray dynamics and combustion processes. Full three-dimensional simulations were conducted using converge as a basic modeling framework, using Reynolds-averaged Navier-Stokes (RANS) turbulent mixing models. An outwardly opening hollow-cone spray injector was characterized and validated against existing and new experimental data. An emphasis was made on the spray penetration characteristics. Various spray breakup and collision models have been

  11. Dual channel formation in a laser-triggered spark gap

    Science.gov (United States)

    Kushner, M. J.; Kimura, W. D.; Ford, D. H.; Byron, S. R.

    1985-12-01

    During self-break in spark-gap switches, multiple streamers can form in close proximity to one another. The rate of expansion of these streamers is sufficiently fast that they can interact during the current pulse. To help understand how these closely spaced, expanding spark columns interact, a laser-triggered spark gap has been studied in which two parallel columns (separation 1.3 mm) are simultaneously preionized, resulting in a pair of nearly identical, axisymmetric spark columns. The spark gap (electrode separation 1.2 cm) switches a 100 ns, 40-60 kV, 12-20 kA, 1.5 Ω waterline. Interferograms of the expanding arc channels are obtained with a laser interferometer having a time and spatial resolution of 5 ns and 10 μm, respectively. Voltage and current were measured with an internal capacitive-voltage divider and a current viewing resistor. The interferograms show that for initially identical axisymmetric columns, the individual channels do not merge into a single larger axisymmetric spark column. Instead, regions of high gas density remain inside the combined column long into the recovery period. The columns also do not remain axisymmetric as they grow, indicating a long-range interaction between the channels. The voltage drop and resistance of the dual channel spark gaps changes by less than 15% from that of a single spark channel. A scaling model is presented to explain the resistance measurements and to predict the change in resistance for multichannel spark gaps.

  12. Survey of Greener Ignition and Combustion Systems for Internal Combustion Engines

    OpenAIRE

    Luo, Wuqiao; Li, Yun; Tian, Zhong; Gao, Bo; Tong, Ling; Wang, Houjun; Zeng, Baoqing

    2015-01-01

    The spark and compression ignition principles of, petrol and diesel internal combustion engines (ICEs) have, not advanced for a century. These do not lead to complete, combustion and hence result in high exhaust emission and, low energy efficiency. This paper presents a comprehensive survey on the attempts and developments of greener ignition, and combustion systems for ICEs and points out that, homogeneous charge microwave ignition (HCMI) holds the, key to a perfect solution. Increasing the ...

  13. Combustion in Homogeneous Charge Compression Ignition Engines: Experiments and Detailed Chemical Kinetic Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Flowers, D L

    2002-06-07

    Homogeneous charge compression ignition (HCCI) engines are being considered as an alternative to diesel engines. The HCCI concept involves premixing fuel and air prior to induction into the cylinder (as is done in current spark-ignition engine) then igniting the fuel-air mixture through the compression process (as is done in current diesel engines). The combustion occurring in an HCCI engine is fundamentally different from a spark-ignition or Diesel engine in that the heat release occurs as a global autoignition process, as opposed to the turbulent flame propagation or mixing controlled combustion used in current engines. The advantage of this global autoignition is that the temperatures within the cylinder are uniformly low, yielding very low emissions of oxides of nitrogen (NO{sub x}, the chief precursors to photochemical smog). The inherent features of HCCI combustion allows for design of engines with efficiency comparable to, or potentially higher than, diesel engines. While HCCI engines have great potential, several technical barriers exist which currently prevent widespread commercialization of this technology. The most significant challenge is that the combustion timing cannot be controlled by typical in-cylinder means. Means of controlling combustion have been demonstrated, but a robust control methodology that is applicable to the entire range of operation has yet to be developed. This research focuses on understanding basic characteristics of controlling and operating HCCI engines. Experiments and detailed chemical kinetic simulations have been applied to the characterize some of the fundamental operational and design characteristics of HCCI engines. Experiments have been conducted on single and multi-cylinder engines to investigate general features of how combustion timing affects the performance and emissions of HCCI engines. Single-zone modeling has been used to characterize and compare the implementation of different control strategies. Multi

  14. Modeling Ignition of a Heptane Isomer: Improved Thermodynamics, Reaction Pathways, Kinetic, and Rate Rule Optimizations for 2-Methylhexane

    KAUST Repository

    Mohamed, Samah

    2016-03-21

    Accurate chemical kinetic combustion models of lightly branched alkanes (e.g., 2-methylalkanes) are important to investigate the combustion behavior of real fuels. Improving the fidelity of existing kinetic models is a necessity, as new experiments and advanced theories show inaccuracies in certain portions of the models. This study focuses on updating thermodynamic data and the kinetic reaction mechanism for a gasoline surrogate component, 2-methylhexane, based on recently published thermodynamic group values and rate rules derived from quantum calculations and experiments. Alternative pathways for the isomerization of peroxy-alkylhydroperoxide (OOQOOH) radicals are also investigated. The effects of these updates are compared against new high-pressure shock tube and rapid compression machine ignition delay measurements. It is shown that rate constant modifications are required to improve agreement between kinetic modeling simulations and experimental data. We further demonstrate the ability to optimize the kinetic model using both manual and automated techniques for rate parameter tunings to improve agreement with the measured ignition delay time data. Finally, additional low temperature chain branching reaction pathways are shown to improve the model’s performance. The present approach to model development provides better performance across extended operating conditions while also strengthening the fundamental basis of the model.

  15. Investigations of the causes of hydrocarbon emissions in spark ignition engines with homogeneous charge compression ignition (HCCI). A report of the Institute for Internal Combustion Engines and Automotive Engineering, TU Vienna (IVK); Untersuchung der Ursachen fuer Kohlenwasserstoff-Emissionen beim Ottomotor mit homogener Selbstzuendung (HCCI). Bericht des Instituts fuer Verbrennungskraftmaschinen und Kraftfahrzeugbau derTechnischen Universitaet Wien (IVK)

    Energy Technology Data Exchange (ETDEWEB)

    Geringer, B. (ed.) [Technische Univ., Vienna (Austria); Loch, A.

    2007-07-01

    The main aim of research and development in the field of internal combustion engine is to create an engine with low fuel consumption and hence low carbon dioxide emissions to meet future emissions regulations as well as providing a good driving experience. Homogeneous charge compression ignition (HCCI) is an alternative combustion process being currently developed that promises a good fuel consumption rate and low nitrogen oxide emissions for the gasoline engine. The only legally restricted exhaust gas emissions for this combustion process are carbon monoxide (CO) and hydrocarbons (HC). The aim of this research was a better understanding of the causes and sources of hydrocarbon emissions with HCCI using gasoline so as to further reduce hydrocarbon emissions. A description of the HCCI combustion process is followed by a list of the known sources of hydrocarbon emission in conventional gasoline engines and current knowledge of the causes of hydrocarbon emission with HCCI. It is assumed that many of the known causes of hydrocarbon emissions in the conventional gasoline combustion process are the same for HCCI. For this reason, this study focused on combustion and carburation, which is where the combustion processes differ the most. (orig.)

  16. Self-ignition of diesel spray combustion

    Science.gov (United States)

    Dhuchakallaya, Isares; Watkins, A. P.

    2009-10-01

    This work presents the development and implementation of auto-ignition modelling for DI diesel engines by using the probability density function-eddy break-up (PDF-EBU) model. The key concept of this approach is to combine the chemical reaction rate dealing with low-temperature mode, and the turbulence reaction rate governing the high-temperature part by a reaction progress variable coupling function which represents the level of reaction. The average reaction rate here is evaluated by a PDF averaging approach. In order to assess the potential of this developed model, the well-known Shell ignition model is chosen to compare in auto-ignition analysis. In comparison, the PDF-EBU ignition model yields the ignition delay time in good agreement with the Shell ignition model prediction. However, the ignition kernel location predicted by the Shell model is slightly nearer injector than that by the PDF-EBU model leading to shorter lift-off length. As a result, the PDF-EBU ignition model developed here are fairly satisfactory in predicting the auto-ignition of diesel engines with the Shell ignition model.

  17. Experimental Study on Stratified and Homogeneous Combustion of a Methanol Direct-Injection Spark-Ignition Engine%甲醇缸内直喷发动机分层燃烧和均质燃烧的试验研究

    Institute of Scientific and Technical Information of China (English)

    李本正; 刘圣华; 农金吉; 宫艳峰

    2009-01-01

    In a methanol direct-injection spark-ignition (DISI) engine retrofitted from a 4-cylinder diesel engine, the fuel needs to be injected into the cylinder near the end of compression stroke to realize the stratified combustion at partial loads for improving fuel economy. However, at high loads, the fuel needs to be injected into cylinder during intake stroke to realize the homogeneous combustion for achieving high power output. The results show that the methanol DISI engine can operate within the excessive air ratio of 2. 23 and its maximum brake thermal efficiency reaches 35. 3%. The methanol DISI engine exhibits higher power output than that of the original diesel engine. The cyclic variations of imep maintains low under a wide range of operating conditions, which shows a stable combustion. NO_x and soot emissions can be de-creased simultaneously.%在一台4缸柴油机改造的火花点火甲醇缸内直喷发动机上,中低负荷时采用分层燃烧来实现好的燃油经济性,高负荷时采用均质燃烧来获得好的动力性能.试验结果表明,甲醇缸内直喷发动机可以实现过量空气系数为2.23的分层稀薄燃烧;发动机的有效热效率最高可达35.3%,远高于普通汽油机;低速转矩大,动力性超过原机水平;在宽广的转速和负荷范围下平均指示压力的循环变动较小,燃烧稳定性好;该甲醇发动机可以实现NO_x和碳烟的同时降低.

  18. Development and Testing of a Green Monopropellant Ignition System

    Science.gov (United States)

    Whitmore, Stephen A.; Merkley, Daniel P.; Eilers, Shannon D.; Judson, Michael I.; Taylor, Terry L.

    2013-01-01

    This paper will detail the development and testing of a "green" monopropellant booster ignition system. The proposed booster ignition technology eliminates the need for a pre-heated catalyst bed, a high wattage power source, toxic pyrophoric ignition fluids, or a bi-propellant spark ignitor. The design offers the simplicity of a monopropellant feed system features non-hazardous gaseous oxygen (GOX) as the working fluid. The approach is fundamentally different from all other "green propellant" solutions in the aerospace in the industry. Although the proposed system is more correctly a "hybrid" rocket technology, since only a single propellant feed path is required, it retains all the simple features of a monopropellant system. The technology is based on the principle of seeding an oxidizing flow with a small amount of hydrocarbon.1 The ignition is initiated electrostatically with a low-wattage inductive spark. Combustion gas byproducts from the hydrocarbon-seeding ignition process can exceed 2400 C and the high exhaust temperature ensures reliable main propellant ignition. The system design is described in detail in the Hydrocarbon-Seeded Ignition System Design subsection.

  19. Antiknock quality and ignition kinetics of 2-phenylethanol, a novel lignocellulosic octane booster

    KAUST Repository

    Shankar, Vijai

    2016-06-28

    High-octane quality fuels are important for increasing spark ignition engine efficiency, but their production comes at a substantial economic and environmental cost. The possibility of producing high anti-knock quality gasoline by blending high-octane bio-derived components with low octane naphtha streams is attractive. 2-phenyl ethanol (2-PE), is one such potential candidate that can be derived from lignin, a biomass component made of interconnected aromatic groups. We first ascertained the blending anti-knock quality of 2-PE by studying the effect of spark advancement on knock for various blends 2-PE, toluene, and ethanol with naphtha in a cooperative fuels research engine. The blending octane quality of 2-PE indicated an anti-knock behavior similar or slightly greater than that of toluene, and ethylbenzene, which could be attributed to either chemical kinetics or charge cooling effects. To isolate chemical kinetic effects, a model for 2-PE auto-ignition was developed and validated using ignition delay times measured in a high-pressure shock tube. Simulated ignition delay times of 2-PE were also compared to those of traditional high-octane gasoline blending components to show that the gas phase reactivity of 2-PE is lower than ethanol, and comparable to toluene, and ethylbenzene at RON, and MON relevant conditions. The gas-phase reactivity of 2-PE is largely controlled by its aromatic ring, while the effect of the hydroxyl group is minimal. The higher blending octane quality of 2-PE compared to toluene, and ethylbenzene can be attributed primarily to the effect of the hydroxyl group on increasing heat of vaporization. © 2016 The Combustion Institute.

  20. The effect of charge motion on mixture preparation and ignition for spark ignition engines with homogeneous combustion processes. A report of the Institute forInternal Combustion Engines and Automotive Engineering, TU Vienna; Einfluss der Ladungsbewegung auf Gemischbildung und Entzuendung bei Otto-Motoren mit homogenen Brennverfahren. Bericht des Instituts fuer Verbrennungskraftmaschinen und Kraftfahrzeugbau der Technischen Universitaet Wien (IVK)

    Energy Technology Data Exchange (ETDEWEB)

    Geringer, B. (ed.); Lauer, T.

    2007-07-01

    The wish to go easy on global oil-resources and the compatibility of environment and traffic are subject of public interest. Therefore, measures must be taken for gasoline engines regarding fuel consumption and CO{sub 2}-emissions. The dethrottling of the intake system by means of residual gas recirculation is a well known measure to reduce the fuel consumption. However, high residual gas concentrations cause a delayed combustion and increased cyclic variations. The specific initiation of charge motion and turbulence in the combustion chamber accelerates and stabilizes the combustion and thus compensates the effects caused by high residual gas concentrations. Because of these complex interactions it is desirable to have the possibility to evaluate the residual gas tolerance of the combustion process at low-load engine operation already during the concept phase. Therefore, it was the aim of this study to develop a method based on numerical simulation that allows a prediction of the combustion stability margin for SI engines with homogeneous combustion for arbitrary in-cylinder flow. Investigations that were carried out with the CFD-method confirmed the acceleration of the combustion with increased turbulence. Further the supporting effect of charge motion on mixture preparation could be pointed out. However, combustion processes with highest swirl-numbers caused a vertical mixture stratification in the combustion chamber with lean mixture at the spark plug resulting in a lower residual gas tolerance. A threshold for a stable combustion could be determined by analyzing the properties of the cylinder charge by means of the flame theory method what further enabled the prediction of the residual gas tolerance of the combustion process and the potential to reduce the fuel consumption. A good correlation between the predicted values of the external residual gas recirculation rate and measurements at the engine test bench could be found. Although improvements of the

  1. Validation of a zero-dimensional and 2-phase combustion model for dual-fuel compression ignition engine simulation

    Directory of Open Access Journals (Sweden)

    Mikulski Maciej

    2017-01-01

    Full Text Available Increasing demands for the reduction of exhaust emissions and the pursuit to re-duce the use of fossil fuels require the search for new fuelling technologies in combustion engines. One of the most promising technologies is the multi-fuel compression ignition engine concept, in which a small dose of liquid fuel injected directly into the cylinder acts as the ignition inhibitor of the gaseous fuel. Achieving the optimum combustion process in such an engine requires the application of advanced control algorithms which require mathematical modelling support. In response to the growing demand for new simulation tools, a 0-D model of a dual-fuel engine was proposed and validated. The validation was performed in a broad range of engine operating points, including various speeds and load condition, as well as different natural gas/diesel blend ratios. It was demonstrated that the average model calculation error within the entire cycle did not exceed 6.2%, and was comparable to the measurement results cycle to cycle variations. The maximum model calculation error in a single point of a cycle was 15% for one of the complex (multipoint injection cases. In other cases, it did not exceed 11%.

  2. Propellant Flow Actuated Piezoelectric Igniter for Combustion Engines

    Science.gov (United States)

    Wollen, Mark A. (Inventor)

    2015-01-01

    A propellant flow actuated piezoelectric igniter device using one or more hammer balls retained by one or more magnets, or other retaining method, until sufficient fluid pressure is achieved to release and accelerate the hammer ball, such that it impacts a piezoelectric crystal to produce an ignition spark. Certain preferred embodiments provide a means for repetitively capturing and releasing the hammer ball after it impacts one or more piezoelectric crystals, thereby oscillating and producing multiple, repetitive ignition sparks. Furthermore, an embodiment is presented for which oscillation of the hammer ball and repetitive impact to the piezoelectric crystal is maintained without the need for a magnet or other retaining mechanism to achieve this oscillating impact process.

  3. Flow-pattern switching in a Motored Spark Ignition Engine

    CERN Document Server

    Abraham, Preeti S; Gupta, Saurabh; Kuo, Tang-Wei; Reuss, David L; Sick, Volker

    2014-01-01

    Cyclic-to-cycle variability, CCV, of intake-jet flow in an optical engine was measured using particle image velocimetry (PIV), revealing the possibility of two different flow patterns. A phase-dependent proper orthogonal decomposition (POD) analysis showed that one or the other flow pattern would appear in the average flow, sampled from test to test or sub-sampled within a single test; each data set contained individual cycles showing one flow pattern or the other. Three-dimensional velocity data from a large-eddy simulation (LES) of the engine showed that the PIV plane was cutting through a region of high shear between the intake jet and another large flow structure. Rotating the measurement plane 10{\\deg} revealed one or the other flow structure observed in the PIV measurements. Thus, it was hypothesized that cycle-to-cycle variations in the swirl ratio result in the two different flow patterns in the PIV plane. Having an unambiguous metric to reveal large-scale flow CCV, causes for this variability were ex...

  4. Ignition of Nanocomposite Thermites by Electric Spark and Shock Wave

    Science.gov (United States)

    2014-04-30

    coating a 0.75 mm thick layer of UV curable acrylic cement (Dymax 401) onto a 6.35-mm thick BK7 glass window. The 8Al ·MoO3 thermite powder, suspended...16] , and measurements of optical emission and pressure generated by the material coated on an electrically heated filament [17, 18]. In all of the...ener- gies, we launched 50 mm thick , 700 mm diameter aluminum flyer plates from a sheet of Al 1145 foil epoxied to a glass window [31]. The Al disks

  5. knock characteristics analysis of a supercharged spark ignition ...

    African Journals Online (AJOL)

    user

    1.6 bar, presently [9 – 11] and as the drive to further downsize engines continues ... dynamometer and various test and control equipment. The photographs of the ..... Method using Cylinder pressure, Block Vibration and Sound ressure Signal ...

  6. Generation of nanoparticles by spark discharge

    Science.gov (United States)

    Tabrizi, N. S.; Ullmann, M.; Vons, V. A.; Lafont, U.; Schmidt-Ott, A.

    2009-02-01

    The production of nanoparticles by microsecond spark discharge evaporation in inert gas is studied systematically applying transmission electron microscopy, mobility analysis and BET surface area measurement. The method of spark discharge is of special interest, because it is continuous, clean, extremely flexible with respect to material, and scale-up is possible. The particle size distributions are narrow and the mean primary particle size can be controlled via the energy per spark. Separated, unagglomerated particles, 3-12 nm in size, or agglomerates can be obtained depending on the flow rate. The nanoparticulate mass produced is typically 5 g/kWh. A formula is given, which estimates the mass production rate via thermal conductivity, evaporation enthalpy and the boiling point of the material used. We showed that with gas purified at the spot, the method produced gold particles that were so clean that sintering of agglomerated particles occurred at room temperature. The influence of a number of parameters on the primary particle size and mass production rate was studied and qualitatively understood with a model of Lehtinen and Zachariah (J Aerosol Sci 33:357-368, 2002). Surprisingly high charging probabilities for one polarity were obtained. Spark generation is therefore of special interest for producing monodisperse aerosols or particles of uniform size via electrical mobility analysis. Qualitative observations in the present study include the phenomenon of material exchange between the electrodes by the spark, which opens the possibility of producing arbitrary mixtures of materials on a nanoscale. If spark generation of nanoparticles is performed in a standing or almost standing gas, an aerogel of a web-like structure forms between surfaces of different electrical potential.

  7. An experimental and modeling study of propene oxidation. Part 2: Ignition delay time and flame speed measurements

    KAUST Repository

    Burke, Sinéad M.

    2015-02-01

    Experimental data obtained in this study (Part II) complement the speciation data presented in Part I, but also offer a basis for extensive facility cross-comparisons for both experimental ignition delay time (IDT) and laminar flame speed (LFS) observables. To improve our understanding of the ignition characteristics of propene, a series of IDT experiments were performed in six different shock tubes and two rapid compression machines (RCMs) under conditions not previously studied. This work is the first of its kind to directly compare ignition in several different shock tubes over a wide range of conditions. For common nominal reaction conditions among these facilities, cross-comparison of shock tube IDTs suggests 20-30% reproducibility (2σ) for the IDT observable. The combination of shock tube and RCM data greatly expands the data available for validation of propene oxidation models to higher pressures (2-40. atm) and lower temperatures (750-1750. K).Propene flames were studied at pressures from 1 to 20. atm and unburned gas temperatures of 295-398. K for a range of equivalence ratios and dilutions in different facilities. The present propene-air LFS results at 1. atm were also compared to LFS measurements from the literature. With respect to initial reaction conditions, the present experimental LFS cross-comparison is not as comprehensive as the IDT comparison; however, it still suggests reproducibility limits for the LFS observable. For the LFS results, there was agreement between certain data sets and for certain equivalence ratios (mostly in the lean region), but the remaining discrepancies highlight the need to reduce uncertainties in laminar flame speed experiments amongst different groups and different methods. Moreover, this is the first study to investigate the burning rate characteristics of propene at elevated pressures (>5. atm).IDT and LFS measurements are compared to predictions of the chemical kinetic mechanism presented in Part I and good

  8. Analysis of Spark Plug Gap on Flame Development using Schlieren Technique and Image Processing

    Science.gov (United States)

    Hii Shu-Yi, Paul; Khalid, Amir; Mohamad, Anuar; Manshoor, Bukhari; Sapit, Azwan; Zaman, Izzuddin; Hashim, Akasha

    2016-11-01

    Gasoline spark ignition system in cars remains one of the main consumption of fuel in the world nowadays. During combustion process, spark plug is one important key features in a gasoline engine. The incompatibility of spark plug gap width and the fuel used causing backfire and knocking in the combustion engine. Thus, the spark plug gap was studied with focussing in controlling the combustion process to improve the performance of the engine. The main purpose of this research is to investigate the effect of spark plug air gap on flame development. The parameters studied in this research include spark plug air gap width (1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm and 1.8 mm), injection pressure (0.3 MPa, 0.4 MPa, 0.5 MPa and 0.6 MPa) and flame characteristics such as flame front area and the flame intensity. The flame front area of different spark plug gap and injection pressure were investigated through Schlieren photography method. The Schlieren images taken were analysed with the time changes. The experiment results proved that the increase of spark plug gap width will led to better flame development in shorter time while increased the chance of misfire.

  9. Review of Solid Propellant Ignition Models Relative to the Interior Ballistic Modelling of Gun Systems

    Science.gov (United States)

    2012-08-01

    the point of phase change is reached. Solid-phase exothermic reactions may occur in some propellant ingredients (such as AP [9] or ADN [4]) leading...M.L. Gross. Two-dimensional modeling of AP/HTPB utilizing a vorticity formula- tion and one-dimensional modeling of AP and ADN . PhD thesis, Brigham

  10. Numerical modeling of a Jet Ignition Direct Injection (JIDI) LPG engine

    OpenAIRE

    albert boretti

    2016-01-01

    The paper presents indirectly validated simulations of the operation of a LPG engine fitted with Direct Injection (DI) and Jet Ignition (JI). It is demonstrated that the engine may have diesel like efficiencies and load control by quantity of fuel injected.  As the liquid propane quickly evaporates after injection in the main chamber, the main chamber mixture may be much closer to stoichiometry than a diesel for a better specific power at low engine speeds. This design also works at the high ...

  11. MECHANISM ON DISTRIBUTION OF PILOT FUEL SPRAY AND COMPRESSING IGNITION IN PREMIXED NATURAL GAS ENGINE IGNITED BY PILOT DIESEL

    Institute of Scientific and Technical Information of China (English)

    Yao Chunde; Yao Guangtao; Song Jinou; Wang Yinshan

    2005-01-01

    Numerical simulations of pilot fuel spray and compressing ignition for pre-mixed natural gas ignited by pilot diesel are described. By means of these modeling, the dual fuel and diesel fuel ignition mechanism of some phenomena investigated on an optional engine by technology of high-speed CCD is analyzed. It is demonstrated that the longer delay of ignition in dual fuel engine is not mainly caused by change of the mixture thermodynamics parameters. The analysis results illustrate that the ignition of pre-mixed natural gas ignited by pilot diesel taking place in dual fuel engine is a process of homogenous charge compression ignition.

  12. Experimental and Kinetic Modeling Study of Extinction and Ignition of Methyl Decanoate in Laminar Nonpremixed Flows

    Energy Technology Data Exchange (ETDEWEB)

    Seshadri, K; Lu, T; Herbinet, O; Humer, S; Niemann, U; Pitz, W J; Law, C K

    2008-01-09

    Methyl decanoate is a large methyl ester that can be used as a surrogate for biodiesel. In this experimental and computational study, the combustion of methyl decanoate is investigated in nonpremixed, nonuniform flows. Experiments are performed employing the counterflow configuration with a fuel stream made up of vaporized methyl decanoate and nitrogen, and an oxidizer stream of air. The mass fraction of fuel in the fuel stream is measured as a function of the strain rate at extinction, and critical conditions of ignition are measured in terms of the temperature of the oxidizer stream as a function of the strain rate. It is not possible to use a fully detailed mechanism for methyl decanoate to simulate the counterflow flames because the number of species and reactions is too large to employ with current flame codes and computer resources. Therefore a skeletal mechanism was deduced from a detailed mechanism of 8555 elementary reactions and 3036 species using 'directed relation graph' method. This skeletal mechanism has only 713 elementary reactions and 125 species. Critical conditions of ignition were calculated using this skeletal mechanism and are found to agree well with experimental data. The predicted strain rate at extinction is found to be lower than the measurements. In general, the methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.

  13. CORONA DISCHARGE IGNITION FOR ADVANCED STATIONARY NATURAL GAS ENGINES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Paul D. Ronney

    2003-09-12

    An ignition source was constructed that is capable of producing a pulsed corona discharge for the purpose of igniting mixtures in a test chamber. This corona generator is adaptable for use as the ignition source for one cylinder on a test engine. The first tests were performed in a cylindrical shaped chamber to study the characteristics of the corona and analyze various electrode geometries. Next a test chamber was constructed that closely represented the dimensions of the combustion chamber of the test engine at USC. Combustion tests were performed in this chamber and various electrode diameters and geometries were tested. The data acquisition and control system hardware for the USC engine lab was updated with new equipment. New software was also developed to perform the engine control and data acquisition functions. Work is underway to design a corona electrode that will fit in the new test engine and be capable igniting the mixture in one cylinder at first and eventually in all four cylinders. A test engine was purchased for the project that has two spark plug ports per cylinder. With this configuration it will be possible to switch between corona ignition and conventional spark plug ignition without making any mechanical modifications.

  14. High quality new type spark plug pressure sensor; Koseino plug gata shiatsu sensor ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Urakawa, H.; Yanagihara, S.; Kawa, T. [Tsukasa Sokken Co. Ltd., Tokyo (Japan); Enomoto, Y. [Musashi Institute of Technology, Tokyo (Japan); Sato, T. [Dai Ichi Institute of Technology, Kagoshima (Japan); Gotthard, E.

    1998-05-01

    Investigations were made on a spark plug type pressure sensor using GaPO4 piezoelectric material developed recently by AVL Corporation. This sensor has the ignition electrode installed decentered to assure the installing position for the pressure sensor, where the small pressure sensor with a diameter of 4.4 mm, model GU12P is installed on the side. Experiments were performed on this sensor, a water cooled sensor for comparison, and a cooling-free type sensor for reference. The engine was operated at an outlet cooling water temperature maintained constant at 80 degC, and experimented in a normal combustion condition with full load at 2000 rpm and 4000 rpm, in a knocking condition with full load at 2000 rpm, and in a transient condition from full load at 4000 rpm to no load at 1300 rpm. As a result, it was made clear that the spark plug type pressure sensor showed an output of the same level as that with the water cooled sensor in the normal combustion pressure. Load change drift under the transient condition was found as good as 2.5% FS at maximum. No effect of columnar vibration was discovered, and a knocking waveform of 14 kHz was observed. 6 refs., 12 figs., 1 tab.

  15. Fast data processing with Spark

    CERN Document Server

    Sankar, Krishna

    2015-01-01

    Fast Data Processing with Spark - Second Edition is for software developers who want to learn how to write distributed programs with Spark. It will help developers who have had problems that were too big to be dealt with on a single computer. No previous experience with distributed programming is necessary. This book assumes knowledge of either Java, Scala, or Python.

  16. Enhanced combustion by jet ignition in a turbocharged cryogenic port fuel injected hydrogen engine

    Energy Technology Data Exchange (ETDEWEB)

    Boretti, Alberto A.; Watson, Harry C. [Department of Mechanical Engineering, The University of Melbourne, 3010 Melbourne (Australia)

    2009-03-15

    The Hydrogen Assisted Jet Ignition (HAJI) is a physico-chemical combustion enhancement system developed at the University of Melbourne. Jet ignition can ignite ultra-lean air/fuel mixtures which are far beyond the stable ignition limit of a spark plug. Jet ignition may further enhance the combustion properties of hydrogen enabling the development of a diesel-like, almost throttle-less, control of load by quantity of fuel injected for higher thermal efficiencies all over the range of loads. The object of this paper is to show the benefits of jet ignition and present the latest results obtained on a four cylinder engine having the jet ignition coupled with cryogenic hydrogen injection and turbo charging. (author)

  17. Large-eddy simulation/probability density function modeling of local extinction and re-ignition in Sandia Flame E

    Science.gov (United States)

    Wang, Haifeng; Popov, Pavel; Hiremath, Varun; Lantz, Steven; Viswanathan, Sharadha; Pope, Stephen

    2010-11-01

    A large-eddy simulation (LES)/probability density function (PDF) code is developed and applied to the study of local extinction and re-ignition in Sandia Flame E. The modified Curl mixing model is used to account for the sub-filter scalar mixing; the ARM1 mechanism is used for the chemical reaction; and the in- situ adaptive tabulation (ISAT) algorithm is used to accelerate the chemistry calculations. Calculations are performed on different grids to study the resolution requirement for this flame. Then, with sufficient grid resolution, full-scale LES/PDF calculations are performed to study the flame characteristics and the turbulence-chemistry interactions. Sensitivity to the mixing frequency model is explored in order to understand the behavior of sub-filter scalar mixing in the context of LES. The simulation results are compared to the experimental data to demonstrate the capability of the code. Comparison is also made to previous RANS/PDF simulations.

  18. Vehicle implementation of a port injected M100 engine using plasma jet ignition and prompt EGR

    Energy Technology Data Exchange (ETDEWEB)

    Gardiner, D.P.; Mallory, R.W.; Rao, V.K.; Bardon, M.F. [Royal Military Coll. of Canada, Kingston, ON (Canada); Battista, V. [Department of Transport, Ottawa, ON (Canada)

    1994-10-01

    Overhead projection slides used at the 1994 Windsor Workshop on Alternative Fuels describing a port-injected engine using plasma jet ignition and prompt EGR were presented. Benefits of the engine were described, accompanied by technical information of its working concepts. Schematics and a comparison of the plasma jet ignition system with conventional spark plug ignition systems were outlined. Cold starting benefits and ignition hypothesis was summarized. Results of graphical analyses of cold-starting with high and normal cranking speeds were reviewed. 16 figs.

  19. Numerical modeling of a Jet Ignition Direct Injection (JIDI LPG engine

    Directory of Open Access Journals (Sweden)

    albert boretti

    2016-12-01

    Full Text Available The paper presents indirectly validated simulations of the operation of a LPG engine fitted with Direct Injection (DI and Jet Ignition (JI. It is demonstrated that the engine may have diesel like efficiencies and load control by quantity of fuel injected.  As the liquid propane quickly evaporates after injection in the main chamber, the main chamber mixture may be much closer to stoichiometry than a diesel for a better specific power at low engine speeds. This design also works at the high engine speeds impossible for the diesel, as combustion within the main chamber is controlled by the turbulent mixing rather than the vaporization and diffusion processes of the injected fuel of the diesel. 

  20. A Phenomenological Model for Prediction Auto-Ignition and Soot Formation of Turbulent Diffusion Combustion in a High Pressure Common Rail Diesel Engine

    Directory of Open Access Journals (Sweden)

    Qinghui Zhou

    2011-06-01

    Full Text Available A new phenomenological model, the TP (Temperature Phase model, is presented to carry out optimization calculations for turbulent diffusion combustion in a high-pressure common rail diesel engine. Temperature is the most important parameter in the TP model, which includes two parts: an auto-ignition and a soot model. In the auto-ignition phase, different reaction mechanisms are built for different zones. For the soot model, different methods are used for different temperatures. The TP model is then implemented in KIVA code instead of original model to carry out optimization. The results of cylinder pressures, the corresponding heat release rates, and soot with variation of injection time, variation of rail pressure and variation of speed among TP model, KIVA standard model and experimental data are analyzed. The results indicate that the TP model can carry out optimization and CFD (computational fluid dynamics and can be a useful tool to study turbulent diffusion combustion.

  1. Miniature free-piston homogeneous charge compression ignition engine-compressor concept - Part II: modeling HCCI combustion in small scales with detailed homogeneous gas phase chemical kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Aichlmayr, H.T.; Kittelson, D.B.; Zachariah, M.R. [The University of Minnesota, Minneapolis (United States). Departments of Mechanical Engineering and Chemistry

    2002-10-01

    Operational maps for crankshaft-equipped miniature homogeneous charge compression ignition engines are established using performance estimation, detailed chemical kinetics, and diffusion models for heat transfer and radical loss. In this study, radical loss was found to be insignificant. In contrast, heat transfer was found to be increasingly significant for 10, 1, and 0.1 W engines, respectively. Also, temperature-pressure trajectories and ignition delay time maps are used to explore relationships between engine operational parameters and HCCI. Lastly, effects of engine operating conditions and design on the indicated fuel conversion efficiency are investigated. (author)

  2. Technical evaluation of vehicle ignition systems: conduct differences between a high energy capacitive system and a standard inductive system

    Directory of Open Access Journals (Sweden)

    Bruno Santos Goulart

    2014-09-01

    Full Text Available An efficient combustion depends on many factors, such as injection, turbulence and ignition characteristics. With the improvement of internal combustion engines the turbulence intensity and internal pressure have risen, demanding more efficient and powerful ignition systems. In direct injection engines, the stratified charge resultant from the wall/air-guided or spray-guided system requires even more energy. The Paschen’s law shows that spark plug gap and mixture density are proportional to the dielectric rupture voltage. It is known that larger spark gaps promote higher efficiency in the internal combustion engines, since the mixture reaction rate rises proportionally. However, the ignition system must be adequate to the imposed gap, not only on energy, but also on voltage and spark duration. For the reported study in this work two test benches were built: a standard inductive ignition system and a capacitive discharge high energy ignition system, with variable voltage and capacitance. The influence of the important parameters energy and ignition voltage on the spark duration, as well as the electrode gap and shape were analyzed. It was also investigated the utilization of a coil with lower resistance and inductance values, as well as spark plugs with and without internal resistances.

  3. Multi-location laser ignition using a spatial light modulator towards improving automotive gasoline engine performance

    Science.gov (United States)

    Kuang, Zheng; Lyon, Elliott; Cheng, Hua; Page, Vincent; Shenton, Tom; Dearden, Geoff

    2017-03-01

    We report on a study into multi-location laser ignition (LI) with a Spatial Light Modulator (SLM), to improve the performance of a single cylinder automotive gasoline engine. Three questions are addressed: i/ How to deliver a multi-beam diffracted pattern into an engine cylinder, through a small opening, while avoiding clipping? ii/ How much incident energy can a SLM handle (optical damage threshold) and how many simultaneous beam foci could thus be created? ; iii/ Would the multi-location sparks created be sufficiently intense and stable to ignite an engine and, if so, what would be their effect on engine performance compared to single-location LI? Answers to these questions were determined as follows. Multi-beam diffracted patterns were created by applying computer generated holograms (CGHs) to the SLM. An optical system for the SLM was developed via modelling in ZEMAX, to cleanly deliver the multi-beam patterns into the combustion chamber without clipping. Optical damage experiments were carried out on Liquid Crystal on Silicon (LCoS) samples provided by the SLM manufacturer and the maximum safe pulse energy to avoid SLM damage found to be 60 mJ. Working within this limit, analysis of the multi-location laser induced sparks showed that diffracting into three identical beams gave slightly insufficient energy to guarantee 100% sparking, so subsequent engine experiments used 2 equal energy beams laterally spaced by 4 mm. The results showed that dual-location LI gave more stable combustion and higher engine power output than single-location LI, for increasingly lean air-fuel mixtures. The paper concludes by a discussion of how these results may be exploited.

  4. Experimental Investigation of Piston Heat Transfer in a Light Duty Engine Under Conventional Diesel, Homogeneous Charge Compression Ignition, and Reactivity Controlled Compression Ignition Combustion Regimes

    Science.gov (United States)

    2014-01-15

    engine speed and load conditions. The closed-cycle integrated and peak heat transfer rates were found to be lower for HCCI and RCCI when compared to...limit the load of HCCI due to practical engine limitations. Additionally, HCCI lacks a fast-response combustion phasing control, such as spark...cylinder research engine under Conventional Diesel (CDC), Homogeneous Charge Compression Ignition ( HCCI ), and Reactivity Controlled Compression Ignition

  5. Modeling and full-scale tests of vortex plasma-fuel systems for igniting high-ash power plant coal

    Science.gov (United States)

    Messerle, V. E.; Ustimenko, A. B.; Karpenko, Yu. E.; Chernetskiy, M. Yu.; Dekterev, A. A.; Filimonov, S. A.

    2015-06-01

    The processes of supplying pulverized-coal fuel into a boiler equipped with plasma-fuel systems and its combustion in the furnace of this boiler are investigated. The results obtained from 3D modeling of conventional coal combustion processes and its firing with plasma-assisted activation of combustion in the furnace space are presented. The plasma-fuel system with air mixture supplied through a scroll is numerically investigated. The dependence of the swirled air mixture flow trajectory in the vortex plasma-fuel system on the scroll rotation angle is revealed, and the optimal rotation angle at which stable plasma-assisted ignition of pulverized coal flame is achieved is determined.

  6. Resistance of a water spark.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Lehr, Jane Marie

    2005-11-01

    The later time phase of electrical breakdown in water is investigated for the purpose of improving understanding of the discharge characteristics. One dimensional simulations in addition to a zero dimensional lumped model are used to study the spark discharge. The goal is to provide better electrical models for water switches used in the pulse compression section of pulsed power systems. It is found that temperatures in the discharge channel under representative drive conditions, and assuming small initial radii from earlier phases of development, reach levels that are as much as an order of magnitude larger than those used to model discharges in atmospheric gases. This increased temperature coupled with a more rapidly rising conductivity with temperature than in air result in a decreased resistance characteristic compared to preceding models. A simple modification is proposed for the existing model to enable the approximate calculation of channel temperature and incorporate the resulting conductivity increase into the electrical circuit for the discharge channel. Comparisons are made between the theoretical predictions and recent experiments at Sandia. Although present and past experiments indicated that preceding late time channel models overestimated channel resistance, the calculations in this report seem to underestimate the resistance relative to recent experiments. Some possible reasons for this discrepancy are discussed.

  7. Chemical Kinetics of Hydrocarbon Ignition in Practical Combustion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C.K.

    2000-07-07

    Chemical kinetic factors of hydrocarbon oxidation are examined in a variety of ignition problems. Ignition is related to the presence of a dominant chain branching reaction mechanism that can drive a chemical system to completion in a very short period of time. Ignition in laboratory environments is studied for problems including shock tubes and rapid compression machines. Modeling of the laboratory systems are used to develop kinetic models that can be used to analyze ignition in practical systems. Two major chain branching regimes are identified, one consisting of high temperature ignition with a chain branching reaction mechanism based on the reaction between atomic hydrogen with molecular oxygen, and the second based on an intermediate temperature thermal decomposition of hydrogen peroxide. Kinetic models are then used to describe ignition in practical combustion environments, including detonations and pulse combustors for high temperature ignition, and engine knock and diesel ignition for intermediate temperature ignition. The final example of ignition in a practical environment is homogeneous charge, compression ignition (HCCI) which is shown to be a problem dominated by the kinetics intermediate temperature hydrocarbon ignition. Model results show why high hydrocarbon and CO emissions are inevitable in HCCI combustion. The conclusion of this study is that the kinetics of hydrocarbon ignition are actually quite simple, since only one or two elementary reactions are dominant. However, there are many combustion factors that can influence these two major reactions, and these are the features that vary from one practical system to another.

  8. Scaling spark on HPC systems

    OpenAIRE

    Chaimov, N; Malony, A.; Canon, S.; C. Iancu; Ibrahim, KZ; Srinivasan, J.

    2016-01-01

    Copyright © 2016 by the Association for Computing Machinery, Inc. (ACM).We report our experiences porting Spark to large production HPC systems. While Spark performance in a data center installation (with local disks) is dominated by the network, our results show that file system metadata access latency can dominate in a HPC installation using Lustre: it determines single node performance up to 4× slower than a typical workstation. We evaluate a combination of software techniques and hardware...

  9. 75 FR 32611 - Standards of Performance for Stationary Compression Ignition and Spark Ignition Internal...

    Science.gov (United States)

    2010-06-08

    ... island areas that are not required to use lower sulfur fuel, while EPA believes that SCR can be installed... different density and viscosity, make it difficult to achieve similar results from SCR as would occur with... located in remote areas of Alaska to petition the Administrator to use any fuels mixed with used oil...

  10. 76 FR 37953 - Standards of Performance for Stationary Compression Ignition and Spark Ignition Internal...

    Science.gov (United States)

    2011-06-28

    ... 2030. DATES: This final rule is effective on August 29, 2011. ADDRESSES: The EPA has established a... Governments G. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks H..., or Use I. National Technology Transfer and Advancement Act J. Executive Order 12898: Federal Actions...

  11. A Theoretical Model for Laser Ignition of Condensed Selfreaction Materials%凝聚态自反应材料激光点火理论模型

    Institute of Scientific and Technical Information of China (English)

    沈平; 连建设; 胡建东; 郭作兴; 孙炳云

    2001-01-01

    基于热理论建立了凝聚态自反应材料的一维激光点火理论模型,并对其作了解析以揭示点火延迟时间与激光处理参数和材料特征之间的关系。尝试进行了激光点燃Ni-33.3at%Al粉末压坯的实验,并将实验值与计算值做了对比以验证模型的合理性。结果表明计算值与实验值吻合较好。因此,激光辐射点火从根本上应归结于热的作用。%A theoretical model for laser -induced ignition of condensed self -reaction materials was set up based on thermal theory,and an analytical solution wassought to reveal the relationship of ignition delay time with laser processing parameters as well as material characteristics. An experiment of laser ignition of Ni - 33.3 at% Al powder compacts was also attempted and the comparison between experimental and computational data of ignition delay time was made to verify the validity of the model. The results show that the calculated values agree well with that of the experiment. As a consequence, the mechanism of ignition by laser beams irradiation can be attributed to thermal in origin.

  12. Modeling and analysis on spark discharge of capacitive circuit with cut-off type protection%截止型保护方式下容性电路短路火花放电模型及分析

    Institute of Scientific and Technical Information of China (English)

    于月森; 张望; 孟庆海; 伍小杰

    2013-01-01

    提出截止型输出短路保护方式下本质安全型开关变换器火花放电的容性等效电路模型.通过在IEC火花试验装置上进行试验,研究截止型保护方式下容性电路火花放电的规律,建立截止型保护方式下容性电路火花放电数学模型.分析与实验表明,建立的数学模型与实际基本相符;截止放电模式与自然放电模式在火花放电规律方面有显著的差异;截止放电模式下减小截止时间和减小电容值均能提高本质安全性能,但在不同取值范围效果不同.%It was proposed that the equivalent circuit model of intrinsically safe switching converter with cut-off type output short circuit protection was capacitive circuit with cut-off type protection. The discharge characteristic of the capacitive circuit with cut-off type protection was found out through a large number of spark discharge experiment in IEC spark test apparatus. The spark discharge mathematical model was established. Analysis and experimental results show that mathematical model is consistent with the reality. The spark discharge laws are significant differences between natural discharge mode and cut-off discharge mode. Under natural discharge mode, both shortening the discharge time and reducing the capacitance value could improve the performance of intrinsical safety, but there are different effects in different value range.

  13. Options for an ignited tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, J.

    1984-02-01

    It is expected that the next phase of the fusion program will involve a tokamak with the goals of providing an ignited plasma for pulses of hundreds of seconds. A simple model is described in this memorandum which establishes the physics conditions for such a self-sustaining plasma, for given ion and electron thermal diffusivities, in terms of R/a, b/a, I, B/q, epsilon ..beta../sub p/, anti T/sub i/, and anti T/sub e//anti T/sub i/. The model is used to produce plots showing the wide range of tokamaks that may ignite or have a given ignition margin. The constraints that limit this range are discussed.

  14. Multi variable control of a switched ignition device: efficiency improvement under various constraints; Commande multivariable d`un moteur a allumage commande: Amelioration du rendement sous differentes contraintes

    Energy Technology Data Exchange (ETDEWEB)

    Chaumerliac, V.

    1995-03-09

    Spark-ignition engine control needs substantial improvement for various reasons: a non-linear and multivariable process, the strictness of anti-pollution constraints, the necessity of fuel economy, the variable running conditions, the aging, the reliability and the cost. The improvement of engine efficiency will be involved in this context and with the pollution constraints. This work develops a system approach and its philosophy is based on a suitable description of the main dynamics. A compartmentalized model of a spark-ignition engine and the dynamic of the vehicle is presented. The aim of this modeling is to have a good representativeness in transients and to describe the behavior of the outputs useful for control. The multivariable control is split in two independent systems. The first one controls the spark advance control to obtain the maximum torque. The second one controls the throttle and the electronic fuel injection device to have lower pollutant emissions. The spark advance closed loop control uses information measured with either a cylinder pressure sensor or a torque sensor. These studies have achieved to an adaptive tuning on engine bench. A new actuator, the electronic throttle control, can provide a higher degree of precision for the fuel/air ratio regulation system, particularly during fast accelerations and decelerations. An intake manifold pressure control is developed to coordinate the air and fuel flows. A delay strategy and a simple compensation of fuel supply dynamics allow to obtain good results on engine bench. Uncoupling the acceleration pedal and the throttle command is a promising way to improve engine efficiency and reduce exhaust emission during transient phases. (author) 59 refs.

  15. High power fiber delivery for laser ignition applications.

    Science.gov (United States)

    Yalin, Azer P

    2013-11-01

    The present contribution provides a concise review of high power fiber delivery research for laser ignition applications. The fiber delivery requirements are discussed in terms of exit energy, intensity, and beam quality. Past research using hollow core fibers, solid step-index fibers, and photonic crystal and bandgap fibers is summarized. Recent demonstrations of spark delivery using large clad step-index fibers and Kagome photonic bandgap fibers are highlighted.

  16. How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

    Science.gov (United States)

    Leins, Martina; Gaiser, Sandra; Schulz, Andreas; Walker, Matthias; Schumacher, Uwe; Hirth, Thomas

    2015-01-01

    This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a stable and continuous operation of the plasma is possible and the plasma torch can be used for many different applications. On one hand, the hot (3,600 K gas temperature) plasma can be used for chemical processes and on the other hand the cold afterglow (temperatures down to almost RT) can be applied for surface processes. For example chemical syntheses are interesting volume processes. Here the microwave plasma torch can be used for the decomposition of waste gases which are harmful and contribute to the global warming but are needed as etching gases in growing industry sectors like the semiconductor branch. Another application is the dissociation of CO2. Surplus electrical energy from renewable energy sources can be used to dissociate CO2 to CO and O2. The CO can be further processed to gaseous or liquid higher hydrocarbons thereby providing chemical storage of the energy, synthetic fuels or platform chemicals for the chemical industry. Applications of the afterglow of the plasma torch are the treatment of surfaces to increase the adhesion of lacquer, glue or paint, and the sterilization or decontamination of different kind of surfaces. The movie will explain how to ignite the plasma solely by microwave power without any additional igniters, e.g., electric sparks. The microwave plasma torch is based on a combination of two resonators — a coaxial one which provides the ignition of the plasma and a cylindrical one which guarantees a continuous and stable operation of the plasma after ignition. The plasma can be operated in a long microwave transparent tube for volume processes or shaped by orifices for surface treatment purposes. PMID:25938699

  17. Dual coil ignition system

    Energy Technology Data Exchange (ETDEWEB)

    Huberts, Garlan J.; Qu, Qiuping; Czekala, Michael Damian

    2017-03-28

    A dual coil ignition system is provided. The dual coil ignition system includes a first inductive ignition coil including a first primary winding and a first secondary winding, and a second inductive ignition coil including a second primary winding and a second secondary winding, the second secondary winding connected in series to the first secondary winding. The dual coil ignition system further includes a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.

  18. The use of beam propagation modeling of Beamlet and Nova to ensure a ``safe`` National Ignition Facility laser system design

    Energy Technology Data Exchange (ETDEWEB)

    Henesian, M.A.; Renard, P.; Auerbach, J. [and others

    1997-03-17

    An exhaustive set of Beamlet and Nova laser system simulations were performed over a wide range of power levels in order to gain understanding about the statistical trends in Nova and Beamlet`s experimental data sets, and to provide critical validation of propagation tools and design ``rules`` applied to the 192-arm National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). The experiments considered for modeling were at 220-ps FWHM duration with unpumped booster slabs on Beamlet, and 100-ps FWHM with pumped 31.5-cm and 46-cm disk amplifiers on Nova. Simulations indicated that on Beamlet, the AB (the intensity pendent phase shift parameter characterizing the tendency towards beam filamentation) for the booster amplifier stage without pumping, would be nearly identical to the AB expected on NIF at the peak of a typical 20-ns long shaped pulse intended for ICF target irradiation. Therefore, with energies less than I kJ in short-pulses, we examined on Beamlet the comparable AB-driven filamentation conditions predicted for long ICF pulseshapes in the 18 kJ regime on the NIF, while avoiding fluence dependent surface damage. Various spatial filter pinhole configurations were examined on Nova and Beamlet. Open transport spatial filter pinholes were used in some experiments to allow the direct measurement of the onset of beam filamentation. Schlieren images on Beamlet of the far field irradiance measuring the scattered light fraction outside of 33-{micro}radians were also obtained and compared to modeled results.

  19. Calcium sparks in the heart: dynamics and regulation

    Directory of Open Access Journals (Sweden)

    Hoang-Trong TM

    2015-10-01

    Full Text Available Tuan M Hoang-Trong,1 Aman Ullah,1 M Saleet Jafri1,21Department of Molecular Neuroscience, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA; 2Biomedical Engineering and Technology, University of Maryland, Baltimore, MD, USAAbstract: Ca2+ plays a central role in the contraction of the heart. It is the bi-directional link between electrical excitation of the heart and contraction. Electrical excitation initiates Ca2+ influx across the sarcolemma and T-tubular membrane that triggered calcium release from the sarcoplasmic reticulum (SR. Ca2+ sparks are the elementary events of calcium release from the SR. Therefore, understanding the dynamics of Ca2+ sparks is essential for understanding the function of the heart. To this end, numerous experimental and computational studies have focused on this topic, exploring the mechanisms of calcium spark initiation, termination, and regulation and what role these play in normal and patho-physiology. The proper understanding of Ca2+ spark regulation and dynamics serves as the foundation for our insights into a multitude of pathological conditions that may develop and that can be the result of structural and/or functional changes at the cellular or subcellular level. Computational modeling of Ca2+ spark dynamics has proven to be a useful tool to understand Ca2+ spark dynamics. This review addresses our current understanding of Ca2+ sparks and how synchronized SR Ca2+ release, in which Ca2+ sparks is a major pathway, is linked to the different cardiac diseases, especially arrhythmias.Keywords: leak, arrhythmia, excitation-contraction coupling, phosphorylation

  20. Development of a self-ignition and combustion model for diesel engines; Modelisation de l`auto-inflammation et de la combustion pour les moteurs diesel

    Energy Technology Data Exchange (ETDEWEB)

    Pires Da Cruz, A.

    1997-12-09

    The work concerns self-ignition and combustion modelling in Diesel engines. Special attention is given to turbulence induced effects. Only gas fuel injection is taken into account. Turbulent mixing is identified as one of the main parameters controlling self-ignition in Diesel engines. However, turbulence effects are often neglected by models currently used in engine calculation codes. A new model based on results obtained by direct numerical simulation (DNS) is proposed. It includes turbulence effects by means of the scalar dissipation rate and presumed pdf of the mixture fraction and a chemical reaction progress variable. The model is validated through several steps. First, its results are compared to DNS in simple mixing and self-ignition cases. Then, its averaged version is integrated into the KIVA2-MB calculation code, where its behavior is tested in a one dimensional version and compared to other formulations. Finally, the model is validated with comparisons to experimental results of methane injection into a high pressure combustion chamber filled with hot air. The combustion chamber allows large optical access and therefore, optical diagnostics can be made. (author) 101 refs.

  1. Development of a self-ignition and combustion model for diesel engines; Modelisation de l`auto-inflammation et de la combustion pour les moteurs diesel

    Energy Technology Data Exchange (ETDEWEB)

    Pires Da Cruz, A.

    1997-12-09

    The work concerns self-ignition and combustion modelling in Diesel engines. Special attention is given to turbulence induced effects. Only gas fuel injection is taken into account. Turbulent mixing is identified as one of the main parameters controlling self-ignition in Diesel engines. However, turbulence effects are often neglected by models currently used in engine calculation codes. A new model based on results obtained by direct numerical simulation (DNS) is proposed. It includes turbulence effects by means of the scalar dissipation rate and presumed pdf of the mixture fraction and a chemical reaction progress variable. The model is validated through several steps. First, its results are compared to DNS in simple mixing and self-ignition cases. Then, its averaged version is integrated into the KIVA2-MB calculation code, where its behavior is tested in a one dimensional version and compared to other formulations. Finally, the model is validated with comparisons to experimental results of methane injection into a high pressure combustion chamber filled with hot air. The combustion chamber allows large optical access and therefore, optical diagnostics can be made. (author) 101 refs.

  2. Tantalum-Tungsten Oxide Thermite Composite Prepared by Sol-Gel Synthesis and Spark Plasma Sintering

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, O; Kuntz, J; Gash, A; Munir, Z

    2009-02-13

    Energetic composite powders consisting of sol-gel derived nanostructured tungsten oxide were produced with various amounts of micrometer-scale tantalum fuel metal. Such energetic composite powders were ignition tested and results show that the powders are not sensitive to friction, spark and/or impact ignition. Initial consolidation experiments, using the High Pressure Spark Plasma Sintering (HPSPS) technique, on the sol-gel derived nanostructured tungsten oxide produced samples with higher relative density than can be achieved with commercially available tungsten oxide. The sol-gel derived nanostructured tungsten oxide with immobilized tantalum fuel metal (Ta - WO{sub 3}) energetic composite was consolidated to a density of 9.17 g.cm{sup -3} or 93% relative density. In addition those parts were consolidated without significant pre-reaction of the constituents, thus the sample retained its stored chemical energy.

  3. Local Ignition in Carbon/Oxygen White Dwarfs -- I: One-zone Ignition and Spherical Shock Ignition of Detonations

    CERN Document Server

    Dursi, L J

    2006-01-01

    The details of ignition of Type Ia supernovae remain fuzzy, despite the importance of this input for any large-scale model of the final explosion. Here, we begin a process of understanding the ignition of these hotspots by examining the burning of one zone of material, and then investigate the ignition of a detonation due to rapid heating at single point. We numerically measure the ignition delay time for onset of burning in mixtures of degenerate material and provide fitting formula for conditions of relevance in the Type Ia problem. Using the neon abundance as a proxy for the white dwarf metallicity, we then find that ignition times can decrease by ~20% with addition of even 5% of neon by mass. When temperature fluctuations that successfully kindle a region are very rare, such a reduction in ignition time can increase the probability of ignition by orders of magnitude. We then consider the ignition of a detonation by an explosive energy input in one localized zone, eg a Sedov blast wave leading to a shock-i...

  4. Off-site ignition probability of flammable gases.

    Science.gov (United States)

    Rew, P J; Spencer, H; Daycock, J

    2000-01-07

    A key step in the assessment of risk for installations where flammable liquids or gases are stored is the estimation of ignition probability. A review of current modelling and data confirmed that ignition probability values used in risk analyses tend to be based on extrapolation of limited incident data or, in many cases, on the judgement of those conducting the safety assessment. Existing models tend to assume that ignition probability is a function of release rate (or flammable gas cloud size) alone and they do not consider location, density or type of ignition source. An alternative mathematical framework for calculating ignition probability is outlined in which the approach used is to model the distribution of likely ignition sources and to calculate ignition probability by considering whether the flammable gas cloud will reach these sources. Data are collated on the properties of ignition sources within three generic land-use types: industrial, urban and rural. These data are then incorporated into a working model for ignition probability in a form capable of being implemented within risk analysis models. The sensitivity of the model results to assumptions made in deriving the ignition source properties is discussed and the model is compared with other available ignition probability methods.

  5. Plane thermonuclear detonation waves initiated by proton beams and quasi-one-dimensional model of fast ignition

    CERN Document Server

    Charakhch'yan, Alexander A

    2014-01-01

    The one-dimensional (1D) problem on bilatiral irradiation by proton beams of the plane layer of condensed DT mixture with length $2H$ and density $\\rho_0 \\leqslant 100\\rho_s$, where $\\rho_s$ is the fuel solid-state density at atmospheric pressure and temperature of 4 K, is considered. The proton kinetic energy is 1 MeV, the beam intensity is $10^{19}$ W/cm$^2$ and duration is 50 ps. A mathematical model is based on the one-fluid two-temperature hydrodynamics with a wide-range equation of state of the fuel, electron and ion heat conduction, DT fusion reaction kinetics, self-radiation of plasma and plasma heating by alpha-particles. If the ignition occurs, a plane detonation wave, which is adjacent to the front of the rarefaction wave, appears. Upon reflection of this detonation wave from the symmetry plane, the flow with the linear velocity profile along the spatial variable $x$ and with a weak dependence of the thermodynamic functions of $x$ occurs. An appropriate solution of the equations of hydrodynamics is...

  6. Auto-ignition modelling: analysis of the dilution effects by the unburnt gases and of the interactions with turbulence for diesel homogeneous charge compression ignition (HCCI) engines; Modelisation de l'auto-inflammation: analyse des effets de la dilution par les gaz brules et des interactions avec la turbulence dediee aux moteurs Diesel a charge homogene

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, G.

    2005-09-15

    Homogeneous Charge Compression Ignition (HCCI) is an alternative engine combustion process that offers the potential for substantial reductions in both NO{sub x} and particulate matter still providing high Diesel-like efficiencies. Combustion in HCCI mode takes place essentially by auto-ignition. It is mainly controlled by the chemical kinetics. It is therefore necessary to introduce detailed chemistry effects in combustion CFD codes in order to properly model the HCCI combustion process. The objective of this work is to develop an auto-ignition model including detailed chemical kinetics and its interactions with turbulence. Also, a comprehensive study has been performed to analyze the chemical influence of CO and H{sub 2} residual species on auto-ignition, which can be present in the exhaust gases. A new auto-ignition model, TKI-PDF (Tabulated Kinetics for Ignition - with turbulent mixing interactions through a pdf approach) dedicated to RANS 3D engine combustion CFD calculations is proposed. The TKI-PDF model is formulated in order to accommodate the detailed chemical kinetics of auto-ignition coupled with turbulence/chemistry interactions. The complete model development and its validation against experimental results are presented in two parts. The first part of this work describes the detailed chemistry input to the model. The second part is dedicated to the turbulent mixing description. A method based on a progress variable reaction rate tabulation is used. A look-up table for the progress variable reaction rates has been built through constant volume complex chemistry simulations. Instantaneous local reaction rates inside the CFD computational cell are then calculated by linear interpolation inside the look-up table depending on the local thermodynamic conditions. In order to introduce the turbulent mixing effects on auto-ignition, a presumed pdf approach is used. The model has been validated in different levels. First, the detailed kinetic approach was

  7. Coil-On-Plug Ignition for LOX/Methane Liquid Rocket Engines in Thermal Vacuum Environments

    Science.gov (United States)

    Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

    2017-01-01

    A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX) / liquid methane rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/methane propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. In order to successfully demonstrate ignition reliability in the vacuum conditions and eliminate corona discharge issues, a coil-on-plug ignition system has been developed. The ICPTA uses spark-plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark-plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp.-2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, Plum Brook testing demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/methane propulsion systems in future spacecraft.

  8. Are Crab nanoshots Schwinger sparks?

    Energy Technology Data Exchange (ETDEWEB)

    Stebbins, Albert [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Yoo, Hojin [Univ. of Wisconsin, Madison, WI (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

    2015-05-21

    The highest brightness temperature ever observed are from "nanoshots" from the Crab pulsar which we argue could be the signature of bursts of vacuum e± pair production. If so this would be the first time the astronomical Schwinger effect has been observed. These "Schwinger sparks" would be an intermittent but extremely powerful, ~103 L, 10 PeV e± accelerator in the heart of the Crab. These nanosecond duration sparks are generated in a volume less than 1 m3 and the existence of such sparks has implications for the small scale structure of the magnetic field of young pulsars such as the Crab. As a result, this mechanism may also play a role in producing other enigmatic bright short radio transients such as fast radio bursts.

  9. Are Crab Nanoshots Schwinger Sparks?

    CERN Document Server

    Stebbins, Albert

    2015-01-01

    The highest brightness temperature ever observed are from "nanoshots" from the Crab pulsar which we argue could be the signature of bursts of vacuum $e^{\\pm}$ pair production. If so this would be the first time the astronomical Schwinger effect has been observed. These "Schwinger sparks" would be an intermittent but extremely powerful, $\\sim 10^3 L_{\\astrosun}$, 10 PeV $e^{\\pm}$ accelerator in the heart of the Crab. These nanosecond duration sparks are generated in a volume less than $1 m^3$ and the existence of such sparks has implications for the small scale structure of the magnetic field of young pulsars such as the Crab. This mechanism may also play a role in producing other enigmatic bright short radio transients such as fast radio bursts.

  10. Theoretical study on ignition compensating temperature sensitivity

    Directory of Open Access Journals (Sweden)

    Mingfang Liu

    2015-09-01

    Full Text Available Temperature sensitivity of the propellant has significant influence on the interior ballistic performance of guns. Many physical and chemical approaches are employed to decrease this temperature sensitivity of the propellant. In this article, it is proposed that the temperature sensitivity of the propellant is changed by altering the factors required to ignition. A one-dimensional two-phase flow interior ballistic model is established to analyze the relation between ignition factors and temperature sensitivity. The simulation results show that the propellant temperature sensitivity is changed by altering the ignition factors. That is, the interior ballistic performance is affected by altering the size of fire hole, breaking liner pressure, and ignition location. Based on the simulation results, the temperature sensitivity can be controlled by matching of charges and intelligent control ignition system.

  11. Bright Sparks of Our Future!

    Science.gov (United States)

    Riordan, Naoimh

    2016-04-01

    My name is Naoimh Riordan and I am the Vice Principal of Rockboro Primary School in Cork City, South of Ireland. I am a full time class primary teacher and I teach 4th class, my students are aged between 9-10 years. My passion for education has developed over the years and grown towards STEM (Science, Technology, Engineering and Mathematics) subjects. I believe these subjects are the way forward for our future. My passion and beliefs are driven by the unique after school programme that I have developed. It is titled "Sparks" coming from the term Bright Sparks. "Sparks" is an after school programme with a difference where the STEM subjects are concentrated on through lessons such as Science, Veterinary Science Computer Animation /Coding, Eco engineering, Robotics, Magical Maths, Chess and Creative Writing. All these subjects are taught through activity based learning and are one-hour long each week for a ten-week term. "Sparks" is fully inclusive and non-selective which gives all students of any level of ability an opportunity to engage into these subjects. "Sparks" is open to all primary students in County Cork. The "Sparks" after school programme is taught by tutors from the different Universities and Colleges in Cork City. It works very well because the tutor brings their knowledge, skills and specialised equipment from their respective universities and in turn the tutor gains invaluable teaching practise, can trial a pilot programme in a chosen STEM subject and gain an insight into what works in the physical classroom.

  12. Characterization of a copper spark discharge plasma in argon atmosphere used for nanoparticle generation

    Science.gov (United States)

    Kohut, Attila; Galbács, Gábor; Márton, Zsuzsanna; Geretovszky, Zsolt

    2017-04-01

    Spark discharge nanoparticle generation is a dynamically developing application of discharge plasmas. In the present study a spark plasma used for nanoparticle generation is characterized by means of spatially and temporally resolved optical emission spectroscopy (OES) supplemented by fast imaging. The data acquired during the generation of copper nanoparticles in argon ambient is used to describe the spatial and temporal evolution of the species in the spark gap and to derive plasma parameters such as excitation temperature and electron concentration on one hand, and the concentration of the Cu species eroded by a single spark on the other. It is shown that temporally and spatially resolved OES together with a simple equilibrium model are efficient tools to estimate the characteristics of the spark discharge plasma that typically exists in spark discharge nanoparticle generators.

  13. Laser performance operations model (LPOM): The computational system that automates the setup and performance analysis of the National Ignition Facility

    Science.gov (United States)

    Shaw, Michael; House, Ronald

    2015-02-01

    The National Ignition Facility (NIF) is a stadium-sized facility containing a 192-beam, 1.8 MJ, 500-TW, 351-nm laser system together with a 10-m diameter target chamber with room for many target diagnostics. NIF is the world's largest laser experimental system, providing a national center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. A computational system, the Laser Performance Operations Model (LPOM) has been developed that automates the laser setup process, and accurately predict laser energetics. LPOM uses diagnostic feedback from previous NIF shots to maintain accurate energetics models (gains and losses), as well as links to operational databases to provide `as currently installed' optical layouts for each of the 192 NIF beamlines. LPOM deploys a fully integrated laser physics model, the Virtual Beamline (VBL), in its predictive calculations in order to meet the accuracy requirements of NIF experiments, and to provide the ability to determine the damage risk to optical elements throughout the laser chain. LPOM determines the settings of the injection laser system required to achieve the desired laser output, provides equipment protection, and determines the diagnostic setup. Additionally, LPOM provides real-time post shot data analysis and reporting for each NIF shot. The LPOM computation system is designed as a multi-host computational cluster (with 200 compute nodes, providing the capability to run full NIF simulations fully parallel) to meet the demands of both the controls systems within a shot cycle, and the NIF user community outside of a shot cycle.

  14. Fiber laser coupled optical spark delivery system

    Science.gov (United States)

    Yalin, Azer [Fort Collins, CO; Willson, Bryan [Fort Collins, CO; Defoort, Morgan [Fort Collins, CO; Joshi, Sachin [Fort Collins, CO; Reynolds, Adam [Fort Collins, CO

    2008-03-04

    A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

  15. Impact of delayed spark restrike on the dynamics of cyclic variability in dilute SI combustion

    Energy Technology Data Exchange (ETDEWEB)

    Kaul, Brian C [ORNL; Wagner, Robert M [ORNL

    2016-01-01

    Spark-ignition (SI) engines can derive substantial efficiency gains from operation at high dilution levels. Additionally, the use of exhaust gas recirculation (EGR) for charge dilution also maintains compatibility with three-way catalysts by allowing stoichiometric operation. However, running high dilution levels increases the occurrence of misfires and partial burns, which induce higher levels of cyclic-variability in engine operation. This variability has been shown to have both stochastic and deterministic components. Factors such as in-cylinder turbulence and mixing-variations can be classified as stochastic; while, charge composition is the major source of the deterministic component through its non-linear effect on ignition and flame propagation characteristics. The use of these deterministic components has been previously explored to construct next-cycle control approaches that would allow stable operation near the edge of stability. Building on that work, this paper aims to understand the effect of spark strategies, specifically the use of a second spark (restrike) after the main spark, on engine operation at high dilution levels that were achieved using both excess air (i.e. lean combustion) and EGR.

  16. Contactless Electric Igniter for Vehicle to Lower Exhaust Emission and Fuel Consumption

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2014-01-01

    Full Text Available An electric igniter for engine/hybrid vehicles is presented. The igniter comprises a flyback converter, a voltage-stacked capacitor, a PIC-based controller, a differential voltage detector, and an ignition coil, of which structure is non-contact type. Since the electric igniter adopts a capacitor to accumulate energy for engine ignition instead of traditional contacttype approach, it enhances the igniting performance of a spark plug effectively. As a result, combustion efficiency is promoted, fuel consumption is saved, and exhaust emission is reduced. The igniter not only is good for fuel efficiency but also can reduce HC and CO emission significantly, which therefore is an environmentally friendly product. The control core of the igniter is implemented on a single chip, which lowers discrete component count, reduces system volume, and increases reliability. In addition, the ignition timing can be programmed so that a timing regulator can be removed from the proposed system, simplifying its structure. To verify the feasibility and functionality of the igniter, key waveforms are measured and real-car experiments are performed as well.

  17. Stability of Ignition Transients

    Directory of Open Access Journals (Sweden)

    V.E. Zarko

    1991-07-01

    Full Text Available The problem of ignition stability arises in the case of the action of intense external heat stimuli when, resulting from the cut-off of solid substance heating, momentary ignition is followed by extinction. Physical pattern of solid propellant ignition is considered and ignition criteria available in the literature are discussed. It is shown that the above mentioned problem amounts to transient burning at a given arbitrary temperature distribution in the condensed phase. A brief survey of published data on experimental and theoretical studies on ignition stability is offered. The comparison between theory and experiment is shown to prove qualitatively the efficiency of the phenomenological approach in the theory. However, the methods of mathematical simulation as well as those of experimental studying of ignition phenomenon, especially at high fluxes, need to be improved.

  18. Streamer-to-spark transition initiated by a nanosecond overvoltage pulsed discharge in air

    Science.gov (United States)

    Lo, A.; Cessou, A.; Lacour, C.; Lecordier, B.; Boubert, P.; Xu, D. A.; Laux, C. O.; Vervisch, P.

    2017-04-01

    This study is focused on the streamer-to-spark transition generated by an overvoltage nanosecond pulsed discharge under atmospheric pressure air in order to provide a quantitative insight into plasma-assisted ignition. The discharge is generated in atmospheric pressure air by the application of a positive high voltage pulse of 35 kV to pin-to-pin electrodes and a rise time of 5 ns. The generated discharge consists of a streamer phase with high voltage and high current followed by a spark phase characterized by a low voltage and a decreasing current in several hundreds of nanosecond. During the streamer phase, the gas temperature measured by optical emission spectroscopy related to the second positive system of nitrogen shows an ultra-fast gas heating up to 1200 K at 15 ns after the current rise. This ultra-fast gas heating, due to the quenching of electronically excited species by oxygen molecules, is followed by a quick dissociation of molecules and then the discharge transition to a spark. At this transition, the discharge contracts toward the channel axis and evolves into a highly conducting thin column. The spark phase is characterized by a high degree of ionization of nitrogen and oxygen atoms shown by the electron number density and temperature measured from optical emission spectroscopy measurements of N+ lines. Schlieren imaging and optical emission spectroscopy techniques provide the time evolution of the spark radius, from which the initial pressure in the spark is estimated. The expansion of the plasma is adiabatic in the early phase. The electronic temperature and density during this phase allows the determination of the isentropic coefficient. The value around 1.2-1.3 is coherent with the high ionization rate of the plasma in the early phase. The results obtained in this study provide a database and the initial conditions for the validation of numerical simulations of the ignition by plasma discharge.

  19. AN INTRODUCTION TO A HOMOGENEOUS CHARGE COMPRESSION IGNITION ENGINE

    Directory of Open Access Journals (Sweden)

    A.A. Hairuddin

    2014-12-01

    Full Text Available Homogeneous charge compression ignition (HCCI engine technology is relatively new and has not matured sufficiently to be commercialised compared with conventional engines. It can use spark ignition or compression ignition engine configurations, capitalizing on the advantages of both: high engine efficiency with low emissions levels. HCCI engines can use a wide range of fuels with low emissions levels. Due to these advantages, HCCI engines are suitable for use in a hybrid engine configuration, where they can reduce the fuel consumption even further. However, HCCI engines have some disadvantages, such as knocking and a low to medium operating load range, which need to be resolved before the engine can be commercialised. Therefore, a comprehensive study has to be performed to understand the behaviour of HCCI engines.

  20. A Study on Homogeneous Charge Compression Ignition Gasoline Engines

    Science.gov (United States)

    Kaneko, Makoto; Morikawa, Koji; Itoh, Jin; Saishu, Youhei

    A new engine concept consisting of HCCI combustion for low and midrange loads and spark ignition combustion for high loads was introduced. The timing of the intake valve closing was adjusted to alter the negative valve overlap and effective compression ratio to provide suitable HCCI conditions. The effect of mixture formation on auto-ignition was also investigated using a direct injection engine. As a result, HCCI combustion was achieved with a relatively low compression ratio when the intake air was heated by internal EGR. The resulting combustion was at a high thermal efficiency, comparable to that of modern diesel engines, and produced almost no NOx emissions or smoke. The mixture stratification increased the local A/F concentration, resulting in higher reactivity. A wide range of combustible A/F ratios was used to control the compression ignition timing. Photographs showed that the flame filled the entire chamber during combustion, reducing both emissions and fuel consumption.

  1. Modeling of low convergence liquid layer wetted foam implosions at the National Ignition Facility

    Science.gov (United States)

    Yi, S. A.; Olson, R. E.; Yin, L.; Wilson, D. C.; Herrmann, H. W.; Zylstra, A. B.; Haines, B. M.; Peterson, R. R.; Bradley, P. A.; Shah, R. C.; Kline, J. L.; Leeper, R. J.; Batha, S. H.; Milovich, J. L.; Berzak Hopkins, L. F.; Ho, D. D.; Meezan, N. B.

    2016-10-01

    A new platform has been developed that allows for lower convergence ratio implosions (CR 15) than is possible with traditional DT ice layered capsules (CR 30). We present HYDRA simulation models of the first low convergence DT implosions on NIF utilizing the wetted foam platform. When tuned to match the observed bangtime and hotspot symmetry, our rad-hydro models agree well with many experimental observables. In particular, the inferred hotspot density and pressure are consistent with simulations, and our modeled burn widths are in better relative agreement with the data than in high convergence implosions. The observed neutron yields are approximately 60-70% of postshot calculations. These results indicate that at a reduced convergence ratio CR 15 the hotspot formation process is well modeled by our simulations. This work was performed under the auspices of the U.S. DOE by the LANS, LLC, Los Alamos National Laboratory under Contract No. DE-AC52-06NA25396.

  2. Experiments and simulations on non-plasma ignition of semiconductor bridge igniter

    Science.gov (United States)

    Du, Weiqiang; Zhou, Bin; Liu, Jupeng; Li, Yong; Wang, Jun

    2017-01-01

    Since semiconductor bridge (SCB) igniter has been invented, it is commonly considered as a plasma generator. However, the plasma ignition mechanism may be affected by the hotspot ignition temperature of the primary explosives that is lower than the melting point of SCB in the igniter. In an effort to investigate the non-plasma ignition performance of SCB igniter, a one-dimensional model was established for temperature distribution analysis under constant current and capacitor discharge excitation. The simulation results featured the progress of heat transfer and the energy level required by non-plasma ignition of SCB was estimated. Furthermore, sensitivity experiments were carried out to test simulation results and to obtain the firing current range of SCB igniter with lead styphnate (LTNR). Experiment results indicated that safety conditions are 1.953 A constant current input lasting 1 ms under constant current excitation and 7.072 V voltage input using 47 µF storage capacitor under capacitor discharge excitation. All-firing conditions of non-plasma ignition are 2.035 A constant current input lasting 1 ms under constant current excitation and 7.647 V voltage input using 47 µF storage capacitor under capacitor discharge excitation.

  3. Mechanistic Models for Ignition and Combustion of Metallic Powders in Different Environments

    Science.gov (United States)

    2010-09-17

    contradicting the expected higher oxidation rate that would be caused a non-continuous Al2O3 layer. A new model of heterogeneous oxidation of Al...accelerated Al oxidation during melting, contradicting the expected higher oxidation rate that would be caused by a non-continuous Al2O3 layer. A model of...particle, respectively, and the constant c accounts for the differences in molar weight and in density between the metal core and the oxide shell

  4. Propagation modeling in two transverse dimensions of the National Ignition Facility baseline performance

    Energy Technology Data Exchange (ETDEWEB)

    Sacks, R.A.; Williams, W.W.; Henesian, M.A.; Orth, C.D.; Haney, S.W.; Trenholme, J.B.; Auerbach, J.M.; Lawson, J.K.

    1997-02-25

    The performance of the NIF baseline design has been modeled in two transverse dimensions using the Fourier optics code PROP92 and the nonlinear harmonic conversion code THG4DO1. The results obtained are in good agreement with those of the ID versions of these codes which were used during the design optimization, yielding good confidence that a near- optimal design has been chosen. We project that this design is able to fulfill NIF`s three major mission specifications without component damage. Further modeling, including the effects of air- path turbulence, quasi-static thermal deformations, SSD, and sensitivity to misalignment and component tolerances is ongoing.

  5. Experimental and Modeling Studies of Plasma Injection by an Electrothermal Igniter Into a Solid Propellant Gun Charge

    Science.gov (United States)

    2006-06-01

    transparent acrylic that allows cinematography of plasma flows and ignition events along the propellant bed. The chamber can withstand pressures up to ~13...formal averaging technique applied to the microscopic flow. These equations require a number of constitutive laws for closure including state equations

  6. Modeling and experiments of x-ray ablation of National Ignition Facility first wall materials

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, A.T.; Burnham, A.K.; Tobin, M.T. [Lawrence Livermore National Lab., CA (United States); Peterson, P.F. [California Univ., Berkeley, CA (United States)

    1996-06-04

    This paper discusses results of modeling and experiments on the x-ray response of selected materials relevant to NIF target chamber design. X-ray energy deposition occurs in such small characteristic depths (on the order of a micron) that thermal conduction and hydrodynamic motion significantly affect the material response, even during the typical 10-ns pulses. The finite-difference ablation model integrates four separate processes: x-ray energy deposition, heat conduction, hydrodynamics, and surface vaporization. Experiments have been conducted at the Nova laser facility in Livermore on response of various materials to NIF-relevant x-ray fluences. Fused silica, Si nitride, B carbide, B, Si carbide, C, Al2O3, and Al were tested. Response was diagnosed using post-shot examinations of the surfaces with SEM and atomic force microscopes. Judgements were made about the dominant removal mechanisms for each material; relative importances of these processes were also studied with the x-ray response model.

  7. Can the inner gap sparking take place in millisecond pulsars?

    Institute of Scientific and Technical Information of China (English)

    Hong-Guang Wang; Guo-Jun Qiao; Ren-Xin Xu

    2003-01-01

    The inner vacuum gap model has become the foundation stone of most theories on pulsar radio emission. The fundamental picture of this model is the sparking, which was conjectured to be induced by magnetic absorption of background gamma photons. However, a question is, can the sparking be triggered in the millisecond pulsars (MSPs) with magnetic fields (B) only about 10s G? We investigate this problem by including the pair production above the inner gap. Under the assumption that the magnetic field is dipolar, our results show the background gamma-ray emission can not be the key factor that triggers the sparking, at least not in MSPs with B ~ 108 G, if the temperature in the polar cap region is only so high as is observed (< 4 × 106 K). Some other mechanisms are required.

  8. Comprehensive study of ignition and combustion of single wooden particles

    DEFF Research Database (Denmark)

    Momenikouchaksaraei, Maryam; Yin, Chungen; Kær, Søren Knudsen

    2013-01-01

    How quickly large biomass particles can ignite and burn out when transported into a pulverized-fuel (pf) furnace and suddenly exposed to a hot gas flow containing oxygen is very important in biomass co-firing design and optimization. In this paper, the ignition and burnout of the largest possible...... for all the test conditions. As the particle is further heated up and the volume-weighted average temperature reaches the onset of rapid decomposition of hemicellulose and cellulose, a secondary homogeneous ignition occurs. The model-predicted ignition delays and burnout times show a good agreement...... with the experimental results. Homogeneous ignition delays are found to scale with specific surface areas while heterogeneous ignition delays show less dependency on the areas. The ignition and burnout are also affected by the process conditions, in which the oxygen concentration is found to have a more pronounced...

  9. Ignition time of self-propagating high-temperature synthesis by laser

    Institute of Scientific and Technical Information of China (English)

    陈森昌; 迟彦惠; 史玉升; 黄树槐

    2002-01-01

    The ignition of self-propagating high-temperature synthesis (SHS) by a laser beam has very well application, but there is lack in study on the ignition process. In order to search the rule of ignition process with laser beam, ignition time of SHS was studied in detail. First one dimension ignition model was introduced: burning is the process in which one layer is ignited by next layer. Then according to Fourier conduction equation, an equation used to calculate the ignition time was deduced. Finally a series of tests were made to verify the equation. The results prove that the change of the parameters in test agrees well with the equation.

  10. Qualification des logiciels numériques. Application à un logiciel d'analyse de la combustion dans les moteurs à allumage commandé Qualification of Numerical Software. Application to a Software for Analysing Combustion in Spark-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Vignes J.

    2006-11-01

    -point arithmetic and highlighting the serious consequences it may have on the results obtained, we describe a probabilistic approach to the analysis of round-off errors, the CESTAC (Contrôle et Estimation STochastique des Arrondis de Calculs method, from the standpoint of both its theoritical bases and its practical implementation. This method has given rise to a new arithmetic, called stochastic arithmetic, the principal properties of which are summed up. Likewise, a probabilistic approach estimating the influence of data errors is described. A software called CADNA (Control of Accuracy and Debugging for Numerical Applications able to automaticaly implement stochastic arithmetic in any Fortran program, is described in this paper. When used in programs implementing the three classes of numerical computing methods (finite, iterative and approximate methods, it can detect numerical instabilities, control branchings and provide accuracy of the results considering the propagation of round-off errors and data errors. It is an efficient tool for validating the results of numerical software. The second part is devoted to the use of the CADNA software for qualifying the simulation software, ANALCO (ANALyse de COmbustion which analyses combustion in spark-ingnition engines. After a description of the normal model of the phenomenon being analyzed and after mathematical model has been deduced, the ANALCO simulation software is described. The results obtained with ANALCO, not using CADNA, reveal the disagreement between the simulation results and the experimental results. The use of the CADNA software eliminates the numerical instabilties, controls the execution of the program and demonstrates that the disagreement between the simulation results and the results observed is due only to numerical problems. Likewise, the CADNA software brings out both the validity range of the model in the light of the data errors and the data that make the mathematical model the most sensitive. From this

  11. IGNITION IMPROVEMENT OF LEAN NATURAL GAS MIXTURES

    Energy Technology Data Exchange (ETDEWEB)

    Jason M. Keith

    2005-02-01

    This report describes work performed during a thirty month project which involves the production of dimethyl ether (DME) on-site for use as an ignition-improving additive in a compression-ignition natural gas engine. A single cylinder spark ignition engine was converted to compression ignition operation. The engine was then fully instrumented with a cylinder pressure transducer, crank shaft position sensor, airflow meter, natural gas mass flow sensor, and an exhaust temperature sensor. Finally, the engine was interfaced with a control system for pilot injection of DME. The engine testing is currently in progress. In addition, a one-pass process to form DME from natural gas was simulated with chemical processing software. Natural gas is reformed to synthesis gas (a mixture of hydrogen and carbon monoxide), converted into methanol, and finally to DME in three steps. Of additional benefit to the internal combustion engine, the offgas from the pilot process can be mixed with the main natural gas charge and is expected to improve engine performance. Furthermore, a one-pass pilot facility was constructed to produce 3.7 liters/hour (0.98 gallons/hour) DME from methanol in order to characterize the effluent DME solution and determine suitability for engine use. Successful production of DME led to an economic estimate of completing a full natural gas-to-DME pilot process. Additional experimental work in constructing a synthesis gas to methanol reactor is in progress. The overall recommendation from this work is that natural gas to DME is not a suitable pathway to improved natural gas engine performance. The major reasons are difficulties in handling DME for pilot injection and the large capital costs associated with DME production from natural gas.

  12. Nanosecond repetitively pulsed discharges in air at atmospheric pressure—the spark regime

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-12-01

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N2 (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 1015 cm-3 towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 1011 cm-3 produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 108 cm-3.

  13. Observations and modeling of debris and shrapnel impacts on optics and diagnostics at the National Ignition Facility

    Directory of Open Access Journals (Sweden)

    Eder D.

    2013-11-01

    Full Text Available A wide range of targets with laser energies spanning two orders of magnitude have been shot at the National Ignition Facility (NIF. The National Ignition Campaign (NIC targets are cryogenic with Si supports and cooling rings attached to an Al Thermo-Mechanical Package (TMP with a thin (30 micron Au hohlraum inside. Particular attention is placed on the low-energy shots where the TMP is not completely vaporized. In addition to NIC targets, a range of other targets has also been fielded on NIF. For all targets, simulations play a critical role in determining if the risks associated with debris and shrapnel are acceptable. In a number of cases, experiments were redesigned, based on simulations, to reduce risks or to obtain data. The majority of these simulations were done using the ALE-AMR code, which provides efficient late-time (100 – 1000 X the pulse duration 3 D calculations of complex NIF targets.

  14. Spark, an application based on Serendipitous Knowledge Discovery.

    Science.gov (United States)

    Workman, T Elizabeth; Fiszman, Marcelo; Cairelli, Michael J; Nahl, Diane; Rindflesch, Thomas C

    2016-04-01

    Findings from information-seeking behavior research can inform application development. In this report we provide a system description of Spark, an application based on findings from Serendipitous Knowledge Discovery studies and data structures known as semantic predications. Background information and the previously published IF-SKD model (outlining Serendipitous Knowledge Discovery in online environments) illustrate the potential use of information-seeking behavior in application design. A detailed overview of the Spark system illustrates how methodologies in design and retrieval functionality enable production of semantic predication graphs tailored to evoke Serendipitous Knowledge Discovery in users.

  15. Mars Spark Source Prototype Developed

    Science.gov (United States)

    Eichenberg, Dennis J.; Lindamood, Glenn R.; VanderWal, Randall L.; Weiland, Karen J.

    2000-01-01

    The Mars Spark Source Prototype (MSSP) hardware was developed as part of a proof of concept system for the detection of trace metals such as lead, cadmium, and arsenic in Martian dusts and soils. A spark discharge produces plasma from a soil sample, and detectors measure the optical emission from metals in the plasma to identify and quantify them. Trace metal measurements are vital in assessing whether or not the Martian environment will be toxic to human explorers. The current method of x-ray fluorescence can yield concentrations of major species only. Other instruments are incompatible with the volume, weight, and power constraints for a Mars mission. The new instrument will be developed primarily for use in the Martian environment, but it would be adaptable for terrestrial use in environmental monitoring. The NASA Glenn Research Center at Lewis Field initiated the development of the MSSP as part of Glenn's Director's Discretionary Fund project for the Spark Analysis Detection of Trace Metal Species in Martian Dusts and Soils. The objective of this project is to develop and demonstrate a compact, sensitive optical instrument for the detection of trace hazardous metals in Martian dusts and soils.

  16. Lifecycle of laser-produced air sparks

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, S. S., E-mail: hari@pnnl.gov; Brumfield, B. E.; Phillips, M. C. [Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352 (United States)

    2015-06-15

    We investigated the lifecycle of laser-generated air sparks or plasmas using multiple plasma diagnostic tools. The sparks were generated by focusing the fundamental radiation from an Nd:YAG laser in air, and studies included early and late time spark dynamics, decoupling of the shock wave from the plasma core, emission from the spark kernel, cold gas excitation by UV radiation, shock waves produced by the air spark, and the spark's final decay and turbulence formation. The shadowgraphic and self-emission images showed similar spark morphology at earlier and late times of its lifecycle; however, significant differences are seen in the midlife images. Spectroscopic studies in the visible region showed intense blackbody-type radiation at early times followed by clearly resolved ionic, atomic, and molecular emission. The detected spectrum at late times clearly contained emission from both CN and N{sub 2}{sup +}. Additional spectral features have been identified at late times due to emission from O and N atoms, indicating some degree of molecular dissociation and excitation. Detailed spatially and temporally resolved emission analysis provides insight about various physical mechanisms leading to molecular and atomic emission by air sparks, including spark plasma excitation, heating of cold air by UV radiation emitted by the spark, and shock-heating.

  17. Laser Diode Ignition (LDI)

    Science.gov (United States)

    Kass, William J.; Andrews, Larry A.; Boney, Craig M.; Chow, Weng W.; Clements, James W.; Merson, John A.; Salas, F. Jim; Williams, Randy J.; Hinkle, Lane R.

    1994-01-01

    This paper reviews the status of the Laser Diode Ignition (LDI) program at Sandia National Labs. One watt laser diodes have been characterized for use with a single explosive actuator. Extensive measurements of the effect of electrostatic discharge (ESD) pulses on the laser diode optical output have been made. Characterization of optical fiber and connectors over temperature has been done. Multiple laser diodes have been packaged to ignite multiple explosive devices and an eight element laser diode array has been recently tested by igniting eight explosive devices at predetermined 100 ms intervals.

  18. Relativistic electrons from sparks in the laboratory

    Science.gov (United States)

    Østgaard, N.; Carlson, B. E.; Nisi, R. S.; Gjesteland, T.; Grøndahl, Ø.; Skeltved, A.; Lehtinen, N. G.; Mezentsev, A.; Marisaldi, M.; Kochkin, P.

    2016-03-01

    Discharge experiments were carried out at the Eindhoven University of Technology in 2013. The experimental setup was designed to search for electrons produced in meter-scale sparks using a 1 MV Marx generator. Negative voltage was applied to the high voltage (HV) electrode. Five thin (1 mm) plastic detectors (5 cm2 each) were distributed in various configurations close to the spark gap. Earlier studies have shown (for HV negative) that X-rays are produced when a cloud of streamers is developed 30-60 cm from the negative electrode. This indicates that the electrons producing the X-rays are also accelerated at this location, that could be in the strong electric field from counterstreamers of opposite polarity. Comparing our measurements with modeling results, we find that ˜300 keV electrons produced about 30-60 cm from the negative electrode are the most likely source of our measurements. A statistical analysis of expected detection of photon bursts by these fiber detectors indicates that only 20%-45% of the detected bursts could be from soft (˜10 keV) photons, which further supports that the majority of detected bursts are produced by relativistic electrons.

  19. Relativistic electrons from sparks in the laboratory

    CERN Document Server

    Østgaard, N; Nisi, R S; Gjesteland, T; Grøndahl, Ø; Skeltved, A; Lehtinen, N G; Mezentsev, A; Marisaldi, M; Kochkin, P

    2016-01-01

    Discharge experiments were carried out at the Eindhoven University of Technology in 2013. The experimental setup was designed to search for electrons produced in meter-scale sparks using a 1 MV Marx generator. Negative voltage was applied to the high voltage (HV) electrode. Five thin (1 mm) plastic detectors (5 $\\rm cm^2$ each) were distributed in various configurations close to the spark gap. Earlier studies have shown (for HV negative) that X-rays are produced when a cloud of streamers is developed 30-60 cm from the negative electrode. This indicates that the electrons producing the X-rays are also accelerated at this location, that could be in the strong electric field from counterstreamers of opposite polarity. Comparing our measurements with modeling results, we find that $\\sim$300 keV electrons produced about 30-60 cm from the negative electrode are the most likely source of our measurements. A statistical analysis of expected detection of photon bursts by these fiber detectors indicates that only 20%-4...

  20. Influence of Small Change of Porosity on Shock Initiation of an HMX/TATB/Viton Explosive and Ignition and Growth Modeling

    Science.gov (United States)

    Liu, Yan; Hussain, Tariq; Huang, Fenglei; Duan, Zhuoping

    2016-07-01

    All solid explosives in practical use are more or less porous. Although it is known that the change in porosity affects the shock sensitivity of solid explosives, the effect of small changes in porosity on the sensitivity needs to be determined for safe and efficient use of explosive materials. In this study, the influence of a small change in porosity on shock initiation and the subsequent detonation growth process of a plastic-bonded explosive PBXC03, composed of 87% cyclotetramethylene-tetranitramine (HMX), 7% triaminotrinitrobenzene (TATB), and 6% Viton by weight, are investigated by shock to detonation transition experiments. Two explosive formulations of PBXC03 having the same initial grain sizes pressed to 98 and 99% of theoretical mass density (1.873 g/cm3) respectively are tested using the in situ manganin piezoresistive pressure gauge technique. Numerical modeling of the experiments is performed using an ignition and growth reactive flow model. Reasonable agreement with the experimental results is obtained by increasing the growth term coefficient in the Lee-Tarver ignition and growth model with porosity. Combining the experimental and simulation results shows that the shock sensitivity increases with porosity for PBXC03 having the same explosive initial grain sizes for the pressures (about 3.1 GPa) applied in the experiments.

  1. Studies of plasma-jet injection systems to improve ignition conditions in S. I. engine combustion. Untersuchung von Plasmastrahl-Zuendsystemen zur Verbesserung der Zuendbedingungen bei der Verbrennung im Ottomotor

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelmi, H.; Lehmann, A. (Technische Hochschule Aachen (Germany). Inst. fuer Industrieofenbau und Waermetechnik im Huettenwesen); Lepperhoff, G.; Schneider, S. (Technische Hochschule Aachen (Germany). Lehrstuhl fuer Angewandte Thermodynamik)

    1992-01-01

    Calorimetric measurements showed that the efficiency of ignition energy transmission can be enhanced by modifying the level and form of stored energy and the geometry of the spark canal. Optical studies reveal the principal benefit of mixture ignition by a plasma jet which is independent of quenching effects. Engine measurements which were designed and implemented as comparative studies on the transistor/coil/ignition and plasma-jet-ignition systems, confirm measurement results obtained in the laboratory. Clear benefits of plasma-jet ignition were identified for all engine parameters, in particular for pollutant emission, fuel consumption and smooth running. (orig./HW).

  2. Modeling Multiple-Core Updraft Plume Rise for an Aerial Ignition Prescribed Burn by Coupling Daysmoke with a Cellular Automata Fire Model

    Directory of Open Access Journals (Sweden)

    Yongqiang Liu

    2012-07-01

    Full Text Available Smoke plume rise is critically dependent on plume updraft structure. Smoke plumes from landscape burns (forest and agricultural burns are typically structured into “sub-plumes” or multiple-core updrafts with the number of updraft cores depending on characteristics of the landscape, fire, fuels, and weather. The number of updraft cores determines the efficiency of vertical transport of heat and particulate matter and therefore plume rise. Daysmoke, an empirical-stochastic plume rise model designed for simulating wildland fire plumes, requires updraft core number as an input. In this study, updraft core number was gained via a cellular automata fire model applied to an aerial ignition prescribed burn conducted at Eglin AFB on 6 February 2011. Typically four updraft cores were simulated in agreement with a photo-image of the plume showing three/four distinct sub-plumes. Other Daysmoke input variables were calculated including maximum initial updraft core diameter, updraft core vertical velocity, and relative emissions production. Daysmoke simulated a vertical tower that mushroomed 1,000 m above the mixing height. Plume rise was validated by ceilometer. Simulations with two temperature profiles found 89–93 percent of the PM2.5 released during the flaming phase was transported into the free atmosphere above the mixing layer. The minimal ground-level smoke concentrations were verified by a small network of particulate samplers. Implications of these results for inclusion of wildland fire smoke in air quality models are discussed.

  3. Underwater spark discharge with long transmission line for cleaning horizontal wells

    Science.gov (United States)

    Lee, Kern; Chung, Kyoung-Jae; Hwang, Y. S.; Kim, C. Y.

    2017-06-01

    A transmission line is discussed for application in an underwater spark-discharge technique in the cleaning of a horizontal well by incorporating a power-transmission model into the simulation. The pulsed-spark-discharge technique has been proposed for clogged-well rehabilitation, because it removes incrustations that are attached to well screens by using strong pressure waves that are generated by the rapid expansion of a spark channel. To apply the pulsed-spark-discharge technique to the cleaning of horizontal wells, the coaxial cable between the pulsed power supply and the spark gap as a load needs to be extended to a few hundred meters. Prior to field application, pulsed-spark-discharge experiments were conducted and the role of the transmission line was examined using an improved simulation model. In the model, a non-linear interaction of the spark channel and the capacitor bank is described by the pulse-forming action of the coaxial cable. Based on the accurate physical properties of the water plasma, such as the equation of state and electrical conductivity within the region of interest, the amount of energy contributed to the development of a shock wave was evaluated. The simulation shows that if the initial conditions of the spark channel are the same, no further reduction in strength of the pressure wave occurs, even if the cable length is increased above 50 m. Hence, the degraded peak pressure that was observed in the experiments using the longer cable is attributed to a change in the initial condition of the spark channel. The parametric study suggests that the low initial charging voltage, the high ambient water pressure, and the long cable length yield the low initial spark-channel density, which results in a reduced peak pressure. The simulation of line charging is presented to discuss the principle of disturbing the pre-breakdown process by an extended cable.

  4. Generation of nanoparticles by spark discharge

    OpenAIRE

    Tabrizi, N.S.; Ullmann, M.; Vons, V.A.; Lafont, U.; Schmidt-Ott, A.

    2008-01-01

    The production of nanoparticles by microsecond spark discharge evaporation in inert gas is studied systematically applying transmission electron microscopy, mobility analysis and BET surface area measurement. The method of spark discharge is of special interest, because it is continuous, clean, extremely flexible with respect to material, and scale-up is possible. The particle size distributions are narrow and the mean primary particle size can be controlled via the energy per spark. Separate...

  5. Plasma spark discharge reactor and durable electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young I.; Cho, Daniel J.; Fridman, Alexander; Kim, Hyoungsup

    2017-01-10

    A plasma spark discharge reactor for treating water. The plasma spark discharge reactor comprises a HV electrode with a head and ground electrode that surrounds at least a portion of the HV electrode. A passage for gas may pass through the reactor to a location proximate to the head to provide controlled formation of gas bubbles in order to facilitate the plasma spark discharge in a liquid environment.

  6. Automatic code generation in SPARK: Applications of computer algebra and compiler-compilers

    Energy Technology Data Exchange (ETDEWEB)

    Nataf, J.M.; Winkelmann, F.

    1992-09-01

    We show how computer algebra and compiler-compilers are used for automatic code generation in the Simulation Problem Analysis and Research Kernel (SPARK), an object oriented environment for modeling complex physical systems that can be described by differential-algebraic equations. After a brief overview of SPARK, we describe the use of computer algebra in SPARK`s symbolic interface, which generates solution code for equations that are entered in symbolic form. We also describe how the Lex/Yacc compiler-compiler is used to achieve important extensions to the SPARK simulation language, including parametrized macro objects and steady-state resetting of a dynamic simulation. The application of these methods to solving the partial differential equations for two-dimensional heat flow is illustrated.

  7. Reduce of Threshold of Laser Inducing Breakdown in Atmosphere by Introducing an Electric Spark

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-Bin; SHI Wei; LI Hua

    2005-01-01

    @@ We report laser-generated plasmas in atmosphere with electrical spark generated by a synchronization circuit.The breakdown thresholds under the conditions that the electrical spark is used and not used are compared.The breakdown threshold has a distinct decrease after the electrical spark is used. Breakdown thresholds as afunction of atmosphere pressure have also been measured at laser wavelengths 532nm and 1064 nm for the laserpulse width of 15ns. We also discuss the principle and performances of the ionized atmosphere by Nd:YAGlaser under the condition of electrical spark introduction. Multiphoton ionization and cascade ionization playimportant roles in the whole process of atmosphere ionization. The free electron induced by electrical spark cansupply the initialization free electron number for multiphoton ionization and cascade ionization. A model forbreakdown in atmosphere, which is in good agreement with the experimental results, is described.

  8. SparkMaster: automated calcium spark analysis with ImageJ.

    Science.gov (United States)

    Picht, Eckard; Zima, Aleksey V; Blatter, Lothar A; Bers, Donald M

    2007-09-01

    Ca sparks are elementary Ca-release events from intracellular Ca stores that are observed in virtually all types of muscle. Typically, Ca sparks are measured in the line-scan mode with confocal laser-scanning microscopes, yielding two-dimensional images (distance vs. time). The manual analysis of these images is time consuming and prone to errors as well as investigator bias. Therefore, we developed SparkMaster, an automated analysis program that allows rapid and reliable spark analysis. The underlying analysis algorithm is adapted from the threshold-based standard method of spark analysis developed by Cheng et al. (Biophys J 76: 606-617, 1999) and is implemented here in the freely available image-processing software ImageJ. SparkMaster offers a graphical user interface through which all analysis parameters and output options are selected. The analysis includes general image parameters (number of detected sparks, spark frequency) and individual spark parameters (amplitude, full width at half-maximum amplitude, full duration at half-maximum amplitude, full width, full duration, time to peak, maximum steepness of spark upstroke, time constant of spark decay). We validated the algorithm using images with synthetic sparks embedded into backgrounds with different signal-to-noise ratios to determine an analysis criteria at which a high sensitivity is combined with a low frequency of false-positive detections. Finally, we applied SparkMaster to analyze experimental data of sparks measured in intact and permeabilized ventricular cardiomyocytes, permeabilized mammalian skeletal muscle, and intact smooth muscle cells. We found that SparkMaster provides a reliable, easy to use, and fast way of analyzing Ca sparks in a wide variety of experimental conditions.

  9. Fusion ignition via a magnetically-assisted fast ignition approach

    CERN Document Server

    Wang, W -M; Sheng, Z -M; Li, Y T; Zhang, J

    2016-01-01

    Significant progress has been made towards laser-driven fusion ignition via different schemes, including direct and indirect central ignition, fast ignition, shock ignition, and impact ignition schemes. However, to reach ignition conditions, there are still various technical and physical challenges to be solved for all these schemes. Here, our multi-dimensional integrated simulation shows that the fast-ignition conditions could be achieved when two 2.8 petawatt heating laser pulses counter-propagate along a 3.5 kilotesla external magnetic field. Within a period of 5 picoseconds, the laser pulses heat a nuclear fuel to reach the ignition conditions. Furthermore, we present the parameter windows of lasers and magnetic fields required for ignition for experimental test.

  10. Imaging Studies of the Effects of Ethanol/Gasoline Blends on Spark-Assisted HCCI

    Science.gov (United States)

    Fatouraie, Mohammad; Wooldridge, Margaret

    2012-10-01

    Spark assist (SA) has been demonstrated to extend the operating limits of homogeneous charge compression ignition (HCCI) modes of engine operation. This experimental investigation focuses on the effects caused by the SA HCCI operation on ignition and combustion properties of 100% indolene and 70% indolene/30% ethanol blends. The spark assist effects are compared to base line HCCI for each blend by varying spark timing at different fuel/air equivalence ratio (φ= 0.4--0.6). High speed imaging is used to understand the effects of flame propagation on heat release rates. Ethanol generally improves engine performance with higher indicated mean effective pressure (IMEP) and higher stability compared to 100% indolene. SA advances phasing within a range of 5 CAD at lower engine speeds (700 rpm) and 11 CAD at higher engine speeds (1200 rpm). SA does not affect heat release rates until immediately (within 5 CAD) prior to autoignition. Unlike previous studies, flames were not observed for all SA conditions. During SA operation, more fuel mass was burned by flame propagation with gasoline compared to E30.

  11. Storytelling through animation: Oxford Sparks

    Science.gov (United States)

    Pyle, D. M.; Cook, A.

    2013-12-01

    Oxford Sparks is a portal that launched in 2012, with the aim of bringing together resources that have been created across the University of Oxford and elsewhere for the purpose of wider engagement with science. To bring attention to this site, Oxford Sparks developed a set of high-quality short animations, each designed to tell a story relating to a current area of science. These animations have been launched on YouTube, and will shortly be available on iTunesU, and have covered broad areas of science from subduction zones (';Underwater Volcano Disaster'), through the early history of the solar system (';Rogue Planet') to the workings of the Large Hadron Collider (';A quick look around the LHC'). The animations have each been developed in close collaboration with researchers, created by a team with experience of education, engagement and outreach. The two minute scripts are intended to be both widely accessible and viewable as ';stand alone' stories. To this end, the scripts are humorous; while the animations are delightfully quirky, and created by professional animator with a degree-level science background. The animations are also intended to be used as ';lesson starters' in school, and educational activities graded for different age groups are being developed in parallel with the animations. They have been used, successfully, on pre-university summer schools, and in university classes. We are gathering both quantitative (analytics) and qualitative (school teacher and student focus group) feedback to monitor the success of the project, and to understand the strengths and weaknesses of the approach. In the first year since launch, Oxford Sparks animations were viewed over 80,000 times on YouTube, in part due to the surge of interest in the Large Hadron Collider animation after the discovery of the Higgs Boson.

  12. Vehicle driving cycle performance of the spark-less di-ji hydrogen engine

    Energy Technology Data Exchange (ETDEWEB)

    Boretti, Alberto A. [School of Science and Engineering, University of Ballarat, PO Box663, Ballarat, VIC 3353 (Australia)

    2010-05-15

    The paper describes coupled CFD combustion simulations and CAE engine performance computations to describe the operation over the full range of load and speed of an always lean burn, Direct Injection Jet Ignition (DI-JI) hydrogen engine. Jet ignition pre-chambers and direct injection are enablers of high efficiencies and load control by quantity of fuel injected. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the spark-less pre-chamber of the DI-JI engine, where it mixes with the air entering from the main chamber and auto-ignites because of the high temperature of the hot glow plug. Then, jets of partially combusted hot gases enter the main chamber igniting there in the bulk, over multiple ignition points, lean stratified mixtures of air and fuel. Engine maps of brake specific fuel consumption vs. speed and brake mean effective pressure are computed first. CAE vehicle simulations are finally performed evaluating the fuel consumption over emission cycles of a vehicle equipped with this engine. (author)

  13. Identification of physical models

    DEFF Research Database (Denmark)

    Melgaard, Henrik

    1994-01-01

    design of experiments, which is for instance the design of an input signal that are optimal according to a criterion based on the information provided by the experiment. Also model validation is discussed. An important verification of a physical model is to compare the physical characteristics...... and Systems Testing), on testing of building components related to passive solar energy conservation, tested under outdoor climate conditions. The second case study is related to the performance of a spark ignition car engine. A phenomenological model of the fuel flow is identified under various operating...

  14. Determination of welding spark parameters for cyclone efficiency calculation (rus

    Directory of Open Access Journals (Sweden)

    Kitain M.B.

    2011-08-01

    Full Text Available Importance of the current work is explained by the problem of air purification in the field of breath of the worker and prevention of the fire and the explosion. To solve this problem the authors offer to use Reverse-flow cyclone as precleaner with spark extinguishing option. In case if the dust includes sparks it is very important to insure that the particles with the sparks will be totally collected in the cyclone, so the collection efficiency for such particles will be 100% in the cyclone. For the estimation of the efficiency of gas purification from the dust particles in the cyclones dust particles features should be determinate, that can be done with the satisfactory accuracy only by physical modeling results. The amount of physical experiments was made by the authors. The methods of determination of the geometric diameter and hydraulic size of the particle consisting sparks were offered. The experimental researches showed that the accuracy of using the geometric diameter of such particle is not enough, because the hydrodynamic characteristics of the particles (such as weight, effective diameter, the way of interaction with the environment can be change in the case of moving. At the same time< hydraulic size, determined in the second part of the experiment, consider all these factors and can be used for the estimation of the cyclone efficiency based on the model of turbulent diffusion with the limited velocity.

  15. Evaluation of plasma jet ignition for improved performance of alternate fuels

    Science.gov (United States)

    Grant, J. F.; Golenko, Z.; McIlwain, M. E.

    1982-08-01

    Alcohols, such as ethanol and methanol, are potential substitutes for gasolines during periods of fuel shortages. The pure alcohols have been reported to cause performance and starting problems when used to fuel internal combustion engines. This study characterized how three modes of ignition, OEM magneto, high energy conventional spark (CI) and plasma jet ignition (PJI) influenced the engine combustion properties of ethanol, methanol and gasoline alcohol blends. Specific combustion properties examined in these measurement were burning velocity and lean limit. In addition, the engine performance was determined for 30% alcohol gasoline containing blends. These engine performance measurements determined brake power, brake specific fuel consumption and brake emissions of carbon monoxide and hydrocarbons. The findings of this study suggest that high energy ignition systems, such as plasma jet ignition, will improve both fuel combustion properties and engine performance.

  16. The combustion chemistry of a fuel tracer: Measured flame speeds and ignition delays and a detailed chemical kinetic model for the oxidation of acetone

    Energy Technology Data Exchange (ETDEWEB)

    Pichon, S.; Black, G.; Simmie, J.M.; Curran, H.J. [Combustion Chemistry Centre, National University of Ireland, Galway (Ireland); Chaumeix, N.; Yahyaoui, M. [Institut de Combustion Aerothermique Reactivite et Environnement, CNRS, Orleans (France); Donohue, R. [Information Technology, National University of Ireland, Galway (Ireland)

    2009-02-15

    Acetone ignition delay and stretch-free laminar flame speed measurements have been carried out and a kinetic model has been developed to simulate these and literature data for acetone and for ketene, which was found to be an important intermediate in its oxidation. The mechanism has been based on one originally devised for dimethyl ether and modified through validation of the hydrogen, carbon monoxide and methane sub-mechanisms. Acetone oxidation in argon was studied behind reflected shock waves in the temperature range 1340-1930 K, at 1 atm and at equivalence ratios of 0.5, 1 and 2; it is also shown that the addition of up to 15% acetone to a stoichiometric n-heptane mixture has no effect on the measured ignition delay times. Flame speeds at 298 K and 1 atm of pure acetone in air were measured in a spherical bomb; a maximum flame speed of {proportional_to}35 cm s{sup -1} at {phi}=1.15 is indicated. (author)

  17. Heat wave fast ignition in inertial confinement energy

    Institute of Scientific and Technical Information of China (English)

    Shalom; Eliezer; Shirly; Vinikman; Pinhasi

    2013-01-01

    An accelerated micro-foil is used to ignite a pre-compressed cylindrical shell containing deuterium–tritium fuel.The well-known shock wave ignition criterion and a novel criterion based on heat wave ignition are developed in this work.It is shown that for heat ignition very high impact velocities are required.It is suggested that a multi-petawatt laser can accelerate a micro-foil to relativistic velocities in a very short time duration(picosecond)of the laser pulse.The cylindrical geometry suggested here for the fast ignition approach has the advantage of geometrically separating the nanosecond lasers that compress the target from the picosecond laser that accelerates the foil.The present model suggests that nuclear fusion by micro-foil impact ignition could be attained with currently existing technology.

  18. Some Observations on the Ignition of Composite Solid Propellants

    Directory of Open Access Journals (Sweden)

    K. Kishore

    1995-07-01

    Full Text Available Heat-up times derived from studies on the ignition characteristics of a few model composite solid propellants, containing polystyrene, carboxy-terminated polybutadiene, plasticised polyvinyl chloride and polyphenol formaldehyde as binders, show that they are directly proportional to the mass of the sample and inversely proportional to the heat flux. Propellant weight-loss prior to ignition and high pressure ignition temperature data on the propellants, ammonium per chlorate, and binders show that the ignition is governed by the gasification of the binder pyrolysis products. The activation energy for the gasification of the pyrolysed polymer products corresponds to their ignition behaviour suggesting that propellant ignition is controlled by the binder.

  19. A time-varying copula mixture for hedging the clean spark spread with wind power futures

    DEFF Research Database (Denmark)

    Christensen, Troels Sønderby; Pircalabu, Anca; Høg, Esben

    2017-01-01

    trading in the spot clean spark spread and wind power futures. To facilitate hedging decisions, we propose a time-varying copula mixture for the joint behavior of the spot clean spark spread and the daily wind index. The model describes the data surprisingly well, both in terms of the marginals...... and the dependence structure, while being straightforward and easy to implement. Based on Monte Carlo simulations from the proposed model, the results indicate that significant benefits can be achieved by using wind power futures to hedge the spot clean spark spread. Moreover, a comparison study shows...

  20. Generation of nanoparticles by spark discharge

    NARCIS (Netherlands)

    Tabrizi, N.S.; Ullmann, M.; Vons, V.A.; Lafont, U.; Schmidt-Ott, A.

    2008-01-01

    The production of nanoparticles by microsecond spark discharge evaporation in inert gas is studied systematically applying transmission electron microscopy, mobility analysis and BET surface area measurement. The method of spark discharge is of special interest, because it is continuous, clean, extr

  1. SparkText: Biomedical Text Mining on Big Data Framework.

    Science.gov (United States)

    Ye, Zhan; Tafti, Ahmad P; He, Karen Y; Wang, Kai; He, Max M

    Many new biomedical research articles are published every day, accumulating rich information, such as genetic variants, genes, diseases, and treatments. Rapid yet accurate text mining on large-scale scientific literature can discover novel knowledge to better understand human diseases and to improve the quality of disease diagnosis, prevention, and treatment. In this study, we designed and developed an efficient text mining framework called SparkText on a Big Data infrastructure, which is composed of Apache Spark data streaming and machine learning methods, combined with a Cassandra NoSQL database. To demonstrate its performance for classifying cancer types, we extracted information (e.g., breast, prostate, and lung cancers) from tens of thousands of articles downloaded from PubMed, and then employed Naïve Bayes, Support Vector Machine (SVM), and Logistic Regression to build prediction models to mine the articles. The accuracy of predicting a cancer type by SVM using the 29,437 full-text articles was 93.81%. While competing text-mining tools took more than 11 hours, SparkText mined the dataset in approximately 6 minutes. This study demonstrates the potential for mining large-scale scientific articles on a Big Data infrastructure, with real-time update from new articles published daily. SparkText can be extended to other areas of biomedical research.

  2. Spark plasma sintering and spark plasma joining of refractory ceramics

    Science.gov (United States)

    Hoefer, Jeffrey Andrew

    Consolidation of refractory ceramics such as boron carbide (B4C) and silicon carbide (SiC) by conventional sintering techniques (pressure-less sintering, hot pressing, hot isostatic pressing etc.) can prove challenging due to the high temperatures required for sintering. Typically sintering additives are used in order to decrease sintering temperature, but at the sacrifice of purity. Typically B4C requires sintering temperatures above 2000°C without the use of additives, while SiC is generally considered not sinterable without additives, and requires temperatures above 2000°C even with additives. Spark Plasma Sintering (SPS) has emerged as a technology that can reduce the sintering temperature considerably compared to more conventional techniques. The simultaneous application of pressure, heat, and current can reduce sintering temperatures without the use of sintering aids to 1600°C and 2000°C for boron carbide and silicon carbide respectively. One shortcoming of SPS, however, is the difficulty in producing complex shapes. Therefore, for carbide materials such as B4C and SiC, which are difficult to machine, the ability to produce complex shapes is worthy of investigation. One means of creating complex shapes is by joining simple shapes. Joining of monolithic ceramics, in particular SiC, has been achieved, however in all cases an intermediate joining material is used (Ti foil, Silica Powder etc.). Joining of materials using SPS, or as it is called, Spark Plasma Joining, can eliminate the need for an intermediate joining material, producing a high purity and high strength joint. This study investigates SPS of 3 different B4C Powders, as well as SPS joining of simple shape monolithic SiC. Sintering parameters such as temperature, pressure, time, and heating rate are all considered. Influence of sintering parameters on density, grain size, mechanical strength, and joint quality is investigated in detail.

  3. Ignition of THKP and TKP pyrotechnic powders :

    Energy Technology Data Exchange (ETDEWEB)

    Maharrey, Sean P.; Erikson, William W; Highley, Aaron M.; Wiese-Smith, Deneille; Kay, Jeffrey J

    2014-03-01

    We have conducted Simultaneous Thermogravimetric Modulated Beam Mass Spectrometry (STMBMS) experiments on igniter/actuator pyrotechnic powders to characterize the reactive processes controlling the ignition and combustion behavior of these materials. The experiments showed a complex, interactive reaction manifold involving over ten reaction pathways. A reduced dimensionality reaction manifold was developed from the detailed 10-step manifold and is being incorporated into existing predictive modeling codes to simulate the performance of pyrotechnic powders for NW component development. The results from development of the detailed reaction manifold and reduced manifold are presented. The reduced reaction manifold has been successfully used by SNL/NM modelers to predict thermal ignition events in small-scale testing, validating our approach and improving the capability of predictive models.

  4. Icelandic newspapers in light of Sparks’ model of different types of press Umræðuvettvangur íslenskra dagblaða með hliðsjón af greiningarramma Colin Sparks

    Directory of Open Access Journals (Sweden)

    Birgir Guðmundsson

    2012-12-01

    Full Text Available It is generally recognized that diversity and plurality of the media are essential for democracy. In the last decade or so concerns have been raised about the content of the new media suggesting that it is becoming more oriented towards entertainment than democratic discussion. This development has been labelled tabloidization and in scholarly discussion the model of Colin Sparks (2000 has in many ways set the reference point. Not many attempts have been made to put the Icelandic press into this model and the little that has been done is several years old. In this paper a content analysis of the Icelandic newspapers for the years 2008-2010 in view of Sparks´ model is reported. To some extent earlier suggestions and findings about the internal positions of Icelandic newspapers relative to each other are confirmed. However the findings show a high level of similarity between the newspapers and suggest that a process of homogenization is occurring in the Icelandic press.Almennt er viðurkennt að fjölbreytni og fjölræði í fjölmiðlum sé grundvallaratriði í lýðræðislegri umræðu. Sífellt háværari hafa þær raddir þó orðið á umliðnum árum sem lýst hafa yfir áhyggjum af því að umræðan í fjölmiðlum hafi verið gengisfelld og meira sé orðið um skemmtun og afþreyingu en þau atriði sem máli skipti fyrir lýðræðið. Þessi þróun hefur verið kölluð "tabloidization" eða götublaðavæðing. Meðal fræðimanna hefur Colin Sparks (2000 einkum mótað umræðuna með greiningarramma sínum um stöðu blaða á opinberum umræðuvettvangi. Fáar tilraunir hafa verið gerðar til að kortleggja íslensk dagblöð samkvæmt þessum greiningarramma og það sem gert hefur verið er orðið margra ára gamalt. Hér er sagt frá innihaldsgreiningu á íslensku dagblöðunum (DV talið sem dagblað á árunum 2008-2010 þar sem miðað er við greiningarramma Sparks. Að hluta til eru fyrri hugmyndir staðfestar, en

  5. Multi-dimensional modelling of spray, in-cylinder air motion and fuel–air mixing in a direct-injection engine

    Indian Academy of Sciences (India)

    N Abani; S Bakshi; R V Ravikrishna

    2007-10-01

    In this work, three-dimensional fuel–air mixing inside a conventional spark ignition engine cylinder is simulated under direct injection conditions. The motivation is to explore retrofitting of conventional engines for direct injection to take advantage of low emissions and high thermal efficiency of the direct injection concept. Fuel–air mixing is studied at different loads by developing and applying a model based on the Lagrangian-drop and Eulerian-fluid (LDEF) procedure for modelling the two-phase flow. The Taylor Analogy Breakup (TAB) model for modelling the hollow cone spray and appropriate models for droplet impingement, drag and evaporation are used. Moving boundary algorithm and two-way interaction between both phases are implemented. Fuel injection timing and quantity is varied with load. Results show that near-stoichiometric fuel–air ratio region is observed at different locations depending on the load. The model developed serves to predict the fuel–air mixing spatially and temporally, and hence is a useful tool in design and optimization of direct injection engines with regards to injector and spark plug locations. Simulations over a range of speed and load indicate the need for a novel ignition strategy involving dual spark plugs and also provide guidelines in deciding spark plug locations.

  6. Direct extrapolation of radial profile data to a self-ignited fusion reactor based on the gyro-Bohm model

    Energy Technology Data Exchange (ETDEWEB)

    Miyazawa, J., E-mail: miyazawa@LHD.nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Goto, T.; Morisaki, T.; Goto, M.; Sakamoto, R.; Motojima, G.; Peterson, B.J.; Suzuki, C.; Ida, K.; Yamada, H.; Sagara, A. [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer The DPE method predicts temperature and density profiles in a fusion reactor. Black-Right-Pointing-Pointer This method is based on the gyro-Bohm type parameter dependence. Black-Right-Pointing-Pointer The size of fusion reactor is determined to fulfill the power balance. Black-Right-Pointing-Pointer The reactor size is proportional to a factor and -4/3 power of the magnetic field. Black-Right-Pointing-Pointer This factor can be a measure of plasma performance like the fusion triple product. - Abstract: A new method named direct profile extrapolation (DPE) has been developed to estimate the radial profiles of temperature and density in a fusion reactor. This method directly extrapolates the radial profiles observed in present experiments to the fusion reactor condition assuming gyro-Bohm type parameter dependence. The magnetohydrodynamic equilibrium that fits the experimental profile data is used to determine the plasma volume. Four enhancement factors for the magnetic field strength, the density, the plasma beta, and the energy confinement are assumed. Then, the plasma size is determined so as to fulfill the power balance in the reactor plasma. The plasma performance can be measured by an index, C{sub exp}, introduced in the DPE method. The minimum magnetic stored energy of the fusion reactor to achieve self-ignition is shown to be proportional to the cube of C{sub exp} and inversely proportional to the square of magnetic field strength. Using this method, the design window of a self-ignited fusion reactor that can be extrapolated from recent experimental results in the Large Helical Device (LHD) is considered. Also discussed is how large an enhancement is needed for the LHD experiment to ensure the helical reactor design of FFHR2m2.

  7. SciSpark: In-Memory Map-Reduce for Earth Science Algorithms

    Science.gov (United States)

    Ramirez, P.; Wilson, B. D.; Whitehall, K. D.; Palamuttam, R. S.; Mattmann, C. A.; Shah, S.; Goodman, A.; Burke, W.

    2016-12-01

    We are developing a lightning fast Big Data technology called SciSpark based on ApacheTM Spark under a NASA AIST grant (PI Mattmann). Spark implements the map-reduce paradigm for parallel computing on a cluster, but emphasizes in-memory computation, "spilling" to disk only as needed, and so outperforms the disk-based Apache Hadoop by 100x in memory and by 10x on disk. SciSpark extends Spark to support Earth Science use in three ways: Efficient ingest of N-dimensional geo-located arrays (physical variables) from netCDF3/4, HDF4/5, and/or OPeNDAP URLS; Array operations for dense arrays in scala and Java using the ND4S/ND4J or Breeze libraries; Operations to "split" datasets across a Spark cluster by time or space or both. For example, a decade-long time-series of geo-variables can be split across time to enable parallel "speedups" of analysis by day, month, or season. Similarly, very high-resolution climate grids can be partitioned into spatial tiles for parallel operations across rows, columns, or blocks. In addition, using Spark's gateway into python, PySpark, one can utilize the entire ecosystem of numpy, scipy, etc. Finally, SciSpark Notebooks provide a modern eNotebook technology in which scala, python, or spark-sql codes are entered into cells in the Notebook and executed on the cluster, with results, plots, or graph visualizations displayed in "live widgets". We have exercised SciSpark by implementing three complex Use Cases: discovery and evolution of Mesoscale Convective Complexes (MCCs) in storms, yielding a graph of connected components; PDF Clustering of atmospheric state using parallel K-Means; and statistical "rollups" of geo-variables or model-to-obs. differences (i.e. mean, stddev, skewness, & kurtosis) by day, month, season, year, and multi-year. Geo-variables are ingested and split across the cluster using methods on the sciSparkContext object including netCDFVariables() for spatial decomposition and wholeNetCDFVariables() for time-series. The

  8. Erosion on spark plug electrodes; Funkenerosion an Zuendkerzenelektroden

    Energy Technology Data Exchange (ETDEWEB)

    Rager, J.

    2006-07-01

    Durability of spark plugs is mainly determined by spark gap widening, caused by electrode wear. Knowledge about the erosion mechanisms of spark plug materials is of fundamental interest for the development of materials with a high resistance against electrode erosion. It is therefore crucial to identify those parameters which significantly influence the erosion behaviour of a material. In this work, a reliable and reproducible testing method is presented which produces and characterizes electrode wear under well-defined conditions and which is capable of altering parameters specifically. Endurance tests were carried out to study the dependence of the wear behaviour of pure nickel and platinum on the electrode temperature, gas, electrode gap, electrode diameter, atmospheric pressure, and partial pressure of oxygen. It was shown that erosion under nitrogen is negligible, irrespective of the material. This disproves all common mechanism discussed in the literature explaining material loss of spark plug electrodes. Based on this observation and the variation of the mentioned parameters a new erosion model was deduced. This relies on an oxidation of the electrode material and describes the erosion of nickel and platinum separately. For nickel, electrode wear is caused by the removal of an oxide layer by the spark. In the case of platinum, material loss occurs due to the plasma-assisted formation and subsequent evaporation of volatile oxides in the cathode spot. On the basis of this mechanism a new composite material was developed whose erosion resistance is superior to pure platinum. Oxidation resistant metal oxide particles were added to a platinum matrix, thus leading to a higher erosion resistance of the composite. However, this can be decreased by a side reaction, the separation of oxygen from the metal oxides, which effectively assists the oxidation of the matrix. This reaction can be suppressed by using highly stable oxides, characterized by a large negative Gibbs

  9. Ignition Studies on Aluminised Propellant.

    Directory of Open Access Journals (Sweden)

    K. A. Bhaskaran

    1996-12-01

    Full Text Available An experimental investigation on the ignition of metallised propellants (APIHTPB/AI has been carried out 10 determine the ignition delay, minimum ignition energy and corresponding heat flux,threshold heat flux for ignition and minimum ignition temperature, Ignition experiments were conductedusing a shock tube under convectiveheating conditions similar to those prevailingin a rocket motor. Heat flux at propellant location was measured by thin film heat flux gauge and also calculated from a ribbon thermocouple output under similar test conditions. The igntion delay was measured as the time lag between the arrival of hot gas at the propellant and the light emission due to actual ignition of the propellant. The experimental results indicate that the ignition delay characteristics are independent of pressure. The minimum energy for ignition obtained for the propellant is 1100J/m2 corresponding to the heat flux range of 80·120 WIcm2 for a gas velocity of 110 mls. The threshold heat flux required to ignite the propellant was 40 W/cm2 at a velocity of 110 mls. Heat flux corresponding to minimum ignition energy and the threshold heat flux increase with gas velocity. The threshold ignition temperature of the propellant was found to be 600 ± 20 K.

  10. GeoSpark SQL: An Effective Framework Enabling Spatial Queries on Spark

    Directory of Open Access Journals (Sweden)

    Zhou Huang

    2017-09-01

    Full Text Available In the era of big data, Internet-based geospatial information services such as various LBS apps are deployed everywhere, followed by an increasing number of queries against the massive spatial data. As a result, the traditional relational spatial database (e.g., PostgreSQL with PostGIS and Oracle Spatial cannot adapt well to the needs of large-scale spatial query processing. Spark is an emerging outstanding distributed computing framework in the Hadoop ecosystem. This paper aims to address the increasingly large-scale spatial query-processing requirement in the era of big data, and proposes an effective framework GeoSpark SQL, which enables spatial queries on Spark. On the one hand, GeoSpark SQL provides a convenient SQL interface; on the other hand, GeoSpark SQL achieves both efficient storage management and high-performance parallel computing through integrating Hive and Spark. In this study, the following key issues are discussed and addressed: (1 storage management methods under the GeoSpark SQL framework, (2 the spatial operator implementation approach in the Spark environment, and (3 spatial query optimization methods under Spark. Experimental evaluation is also performed and the results show that GeoSpark SQL is able to achieve real-time query processing. It should be noted that Spark is not a panacea. It is observed that the traditional spatial database PostGIS/PostgreSQL performs better than GeoSpark SQL in some query scenarios, especially for the spatial queries with high selectivity, such as the point query and the window query. In general, GeoSpark SQL performs better when dealing with compute-intensive spatial queries such as the kNN query and the spatial join query.

  11. Effect of ignition timing and hydrogen fraction on combustion and emission characteristics of natural gas direct-injection engine

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An experimental study on the combustion and emission characteristics of a direct-injection spark-ignited engine fueled with natural gas/hydrogen blends under various ignition timings was conducted.The results show that ignition timing has a significant influence on engine performance,combustion and emissions.The interval between the end of fuel injection and ignition timing is a very important parameter for direct-injection natural gas engines.The turbulent flow in the combustion chamber generated by the fuel jet remains high and relative strong mixture stratification is introduced when decreasing the angle interval between the end of fuel injection and ignition timing giving fast burning rates and high thermal efficiencies.The maximum cylinder gas pressure,maximum mean gas temperature,maximum rate of pressure rise and maximum heat release rate increase with the advancing of ignition timing.However,these parameters do not vary much with hydrogen addition under specific ignition timing indicating that a small hydrogen fraction addition of less than 20% in the present experiment has little influence on combustion parameters under specific ignition timing.The exhaust HC emission decreases while the exhaust CO2 concentration increases with the advancing of ignition timing.In the lean combustion condition,the exhaust CO does not vary much with ignition timing.At the same ignition timing,the exhaust HC decreases with hydrogen addition while the exhaust CO and CO2 do not vary much with hydrogen addition.The exhaust NOx increases with the advancing of' ignition timing and the behavior tends to be more obvious at large ignition advance angle.The brake mean effective pressure and the effective thermal efficiency of natural gas/hydrogen mixture combustion increase compared with those of natural gas combustion when the hydrogen fraction is over 10%.

  12. Method for operating an automobile with a combustion engine with applied ignition

    Energy Technology Data Exchange (ETDEWEB)

    Anderton, R.A.; Smith, R.R.; Tippler, R.

    1982-01-28

    A method is proposed to operate automobiles with combustion engines with applied ignition directly after the assembly on a petrol-mineral oil mixture; this prevents a spark plug fouling when the cars which hare just been completed are operated on short distances only. This petrol-mineral oil mixture should consist preferably of 95-98 ROZ petrol and mineral oil share of less than 5 vol.% preferably 0,5 vol.%.

  13. Indirect drive ignition at the National Ignition Facility

    Science.gov (United States)

    Meezan, N. B.; Edwards, M. J.; Hurricane, O. A.; Patel, P. K.; Callahan, D. A.; Hsing, W. W.; Town, R. P. J.; Albert, F.; Amendt, P. A.; Berzak Hopkins, L. F.; Bradley, D. K.; Casey, D. T.; Clark, D. S.; Dewald, E. L.; Dittrich, T. R.; Divol, L.; Döppner, T.; Field, J. E.; Haan, S. W.; Hall, G. N.; Hammel, B. A.; Hinkel, D. E.; Ho, D. D.; Hohenberger, M.; Izumi, N.; Jones, O. S.; Khan, S. F.; Kline, J. L.; Kritcher, A. L.; Landen, O. L.; LePape, S.; Ma, T.; MacKinnon, A. J.; MacPhee, A. G.; Masse, L.; Milovich, J. L.; Nikroo, A.; Pak, A.; Park, H.-S.; Peterson, J. L.; Robey, H. F.; Ross, J. S.; Salmonson, J. D.; Smalyuk, V. A.; Spears, B. K.; Stadermann, M.; Suter, L. J.; Thomas, C. A.; Tommasini, R.; Turnbull, D. P.; Weber, C. R.

    2017-01-01

    This paper reviews scientific results from the pursuit of indirect drive ignition on the National Ignition Facility (NIF) and describes the program’s forward looking research directions. In indirect drive on the NIF, laser beams heat an x-ray enclosure called a hohlraum that surrounds a spherical pellet. X-ray radiation ablates the surface of the pellet, imploding a thin shell of deuterium/tritium (DT) that must accelerate to high velocity (v  >  350 km s-1) and compress by a factor of several thousand. Since 2009, substantial progress has been made in understanding the major challenges to ignition: Rayleigh Taylor (RT) instability seeded by target imperfections; and low-mode asymmetries in the hohlraum x-ray drive, exacerbated by laser-plasma instabilities (LPI). Requirements on velocity, symmetry, and compression have been demonstrated separately on the NIF but have not been achieved simultaneously. We now know that the RT instability, seeded mainly by the capsule support tent, severely degraded DT implosions from 2009-2012. Experiments using a ‘high-foot’ drive with demonstrated lower RT growth improved the thermonuclear yield by a factor of 10, resulting in yield amplification due to alpha particle heating by more than a factor of 2. However, large time dependent drive asymmetry in the LPI-dominated hohlraums remains unchanged, preventing further improvements. High fidelity 3D hydrodynamic calculations explain these results. Future research efforts focus on improved capsule mounting techniques and on hohlraums with little LPI and controllable symmetry. In parallel, we are pursuing improvements to the basic physics models used in the design codes through focused physics experiments.

  14. Spark discharge in conductive liquid with microbubbles

    Science.gov (United States)

    Vetchinin, S. P.; Vasilyak, L. M.; Pecherkin, V. Ya; Panov, V. A.; Son, E. E.

    2016-11-01

    Pulse electrical breakdown in 15% water solution of Isopropyl alcohol with air microbubbles from a pointed anode has been studied experimentally. It is shown, that the breakdown is always initiated from the bright region near the anode (anode “spot”). Detailed investigation into dynamic current-voltage characteristics and synchronized images reveals that it is thermal instability in the near anode region that causes spark channel initiation and development. The breakdown voltage, spark channel propagation speed and short-circuit current increase when the microbubbles are presented in the solution. The spark channel propagation speed is about 4-12 m/s and grows along with microbubbles concentration.

  15. Boron Particle Ignition in Secondary Chamber of Ducted Rocket

    Directory of Open Access Journals (Sweden)

    J. X. Hu

    2012-01-01

    Full Text Available In the secondary chamber of ducted rocket, there exists a relative speed between boron particles and air stream. Hence, the ignition laws under static conditions cannot be simply applied to represent the actual ignition process of boron particles, and it is required to study the effect of forced convective on the ignition of boron particles. Preheating of boron particles in gas generator makes it possible to utilize the velocity difference between gas and particles in secondary chamber for removal of the liquid oxide layer with the aid of Stoke's forces. An ignition model of boron particles is formulated for the oxide layer removal by considering that it results from a boundary layer stripping mechanism. The shearing action exerted by the high-speed flow causes a boundary layer to be formed in the surface of the liquid oxide layer, and the stripping away of this layer accounts for the accelerated ignition of boron particles. Compared with the King model, as the ignition model of boron particles is formulated for the oxide layer removal by considering that it results from a boundary layer stripping mechanism, the oxide layer thickness thins at all times during the particle ignition and lower the ignition time.

  16. Experimental investigation of the vibrational and thermal response of a laser spark plug

    Science.gov (United States)

    Yoder, Gregory S.

    A study was conducted in order to evaluate the external thermal and vibrational effects on the operation of a laser ignition system for internal combustion (IC) engine applications. West Virginia University (WVU) in conjunction with the National Energy Technology Laboratory (NETL) have constructed a prototype laser spark plug which has been designed to mount directly onto the head of a natural gas engine for the purpose of igniting an air/fuel (A/F) mixture in the engine's combustion chamber. To be considered as a viable replacement for the conventional electrode-based ignition system, integrity, durability and reliability must be justified. Thermal and oscillatory perturbations induced upon the ignition system are major influences that affect laser spark plug (LSP) operation and, therefore, quantifying these effects is necessary to further the advancement and development of this technology. The passively q-switched Nd:YAG laser was mounted on Bruel & Kjaer (B&K) Vibration Exciter Type 4808 Shaker in conjunction with at B&K Power Amplifier Type 2719, which was oscillated in 10 Hz intervals from 0 to 60 Hz using a sine wave to mimic natural gas engine operation. The input signal simulated the rotational velocity of the engine operating from 0 to 3600 RPM with the laser mounted in three different axial orientations. The laser assembly was wrapped with medium-temperature heat tape, outfitted with thermocouples and heated from room temperature to 140 ºF to simulate the temperatures that the LSP may experience when installed on an engine. The acceleration of the payload was varied between 50% and 100% of the oscillator's maximum allowable acceleration in each mounting orientation resulting in a total of 294 total setpoints. For each setpoint, pulse width, pulse width variation, q-switch delay, jitter and output energy were measured and recorded. Each of these dependent variables plays a critical role in multi photon ionization and precise control is necessary to limit

  17. Mechanochemical synthesis and spark plasma sintering of the cerium silicides

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, Gordon A.; Jaques, Brian; Bateman, Allyssa [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Butt, Darryl P., E-mail: darrylbutt@boisestate.edu [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Boulevard, Idaho Falls, ID 83401 (United States)

    2014-12-15

    Highlights: • Ce{sub 5}Si{sub 3}, Ce{sub 3}Si{sub 2}, CeSi, CeSi{sub 2−x} and CeSi{sub 2} were mechanochemically synthesized. • Temperature and pressure were monitored to investigate reaction progress. • All syntheses proceeded through a MSR event followed by rapid solid-state diffusion. • Milling time before MSR correlates well with effective heat of formation. • Some synthesized material was densified by spark plasma sintering. - Abstract: The cerium silicides, Ce{sub 5}Si{sub 3}, Ce{sub 3}Si{sub 2}, CeSi, CeSi{sub 2−y}, and CeSi{sub 2−x}, have been prepared from the elements by mechanochemical processing in a planetary ball mill. Preparation of the cerium silicide Ce{sub 5}Si{sub 4} was unsuccessfully attempted and potential reasons for this are discussed. Temperature and pressure of the milling vial were monitored in situ to gain insight into the mechanochemical reaction kinetics, which include a mechanically-induced self-propagating reaction (MSR). Some prepared powders were consolidated by spark plasma sintering to high density. Starting materials, as-milled powders, and consolidated samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The results obtained help elucidate key questions in mechanochemical processing of intermetallics, showing first phase formation similar to thin films, MSR ignition times that are composition- and milling speed-dependent, and sensitivity of stable compound formation on the impact pressure. The results demonstrate mechanochemical synthesis as a viable technique for rare earth silicides.

  18. Possible version of the compression degradation of the thermonuclear indirect-irradiation targets at the national ignition facility and a reason for the failure of ignition

    Science.gov (United States)

    Rozanov, V. B.; Vergunova, G. A.

    2017-01-01

    The main parameters of compression of a target and tendencies at change in the irradiation conditions are determined by analyzing the published results of experiments at the megajoule National Ignition Facility (NIF) on the compression of capsules in indirect-irradiation targets by means of the one-dimensional RADIAN program in the spherical geometry. A possible version of the "failure of ignition" of an indirect-irradiation target under the NIF conditions is attributed to radiation transfer. The application of onedimensional model to analyze the National Ignition Campaign (NIC) experiments allows identifying conditions corresponding to the future ignition regime and distinguishing them from conditions under which ignition does not occur.

  19. COMPUTER ALGORITHMS FOR EVALUATION OF SPARKING INDICATED BY OPTOELECTRONIC SPARKING ANALYZER

    Directory of Open Access Journals (Sweden)

    W. Zelinski

    2005-01-01

    Full Text Available Optoelectronic sparking analyzer provides the possibility to realize a number of algorithms that permit to convert indicated light signals containing information on number of sparkings in the measuring cycle and their intensity divided in ten classes. The paper presents the selected sparking indices converted with the help of a computer and these indices make it possible to evaluate sparking level of separate commutator sectors by calculating average values in the whole measuring cycle of brush-commutator contact in dc machines. The paper also contains limiting values of the presented indices. 

  20. Titian: Data Provenance Support in Spark.

    Science.gov (United States)

    Interlandi, Matteo; Shah, Kshitij; Tetali, Sai Deep; Gulzar, Muhammad Ali; Yoo, Seunghyun; Kim, Miryung; Millstein, Todd; Condie, Tyson

    2015-11-01

    Debugging data processing logic in Data-Intensive Scalable Computing (DISC) systems is a difficult and time consuming effort. Today's DISC systems offer very little tooling for debugging programs, and as a result programmers spend countless hours collecting evidence (e.g., from log files) and performing trial and error debugging. To aid this effort, we built Titian, a library that enables data provenance-tracking data through transformations-in Apache Spark. Data scientists using the Titian Spark extension will be able to quickly identify the input data at the root cause of a potential bug or outlier result. Titian is built directly into the Spark platform and offers data provenance support at interactive speeds-orders-of-magnitude faster than alternative solutions-while minimally impacting Spark job performance; observed overheads for capturing data lineage rarely exceed 30% above the baseline job execution time.

  1. Study on the ignition process of a segmented plasma torch

    Science.gov (United States)

    Cao, Xiuquan; Yu, Deping; Xiang, Yong; Li, Chao; Jiang, Hui; Yao, Jin

    2017-07-01

    Direct current plasma torches have been applied to generate unique sources of thermal energy in many industrial applications. Nevertheless, the successful ignition of a plasma torch is the key process to generate the unique source (plasma jet). However, there has been little study on the underlying mechanism of this key process. A thorough understanding of the ignition process of a plasma torch will be helpful for optimizing the design of the plasma torch structure and selection of the ignition parameters to prolong the service life of the ignition module. Thus, in this paper, the ignition process of a segmented plasma torch (SPT) is theoretically and experimentally modeled and analyzed. Corresponding electrical models of different stages of the ignition process are set up and used to derive the electrical parameters, e.g. the variations of the arc voltage and arc current between the cathode and anode. In addition, the experiments with different ignition parameters on a home-made SPT have been conducted. At the same time, the variations of the arc voltage and arc current have been measured, and used to verify the ones derived in theory and to determine the optimal ignition parameters for a particular SPT.

  2. Isochoric Implosions for Fast Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D S; Tabak, M

    2007-04-04

    Various gain models have shown the potentially great advantages of Fast Ignition (FI) Inertial Confinement Fusion (ICF) over its conventional hot spot ignition counterpart [e.g., S. Atzeni, Phys. Plasmas 6, 3316 (1999); M. Tabak et al., Fusion Sci. & Technology 49, 254 (2006)]. These gain models, however, all assume nearly uniform-density fuel assemblies. In contrast, conventional ICF implosions yield hollowed fuel assemblies with a high-density shell of fuel surrounding a low-density, high-pressure hot spot. Hence, to realize fully the advantages of FI, an alternative implosion design must be found which yields nearly isochoric fuel assemblies without substantial hot spots. Here, it is shown that a self-similar spherical implosion of the type originally studied by Guderley [Luftfahrtforschung 19, 302 (1942)] may be employed to yield precisely such quasi-isochoric imploded states. The difficulty remains, however, of accessing these self-similarly imploding configurations from initial conditions representing an actual ICF target, namely a uniform, solid-density shell at rest. Furthermore, these specialized implosions must be realized for practicable drive parameters and at the scales and energies of interest in ICF. A direct-drive implosion scheme is presented which meets all of these requirements and reaches a nearly isochoric assembled density of 300 g=cm{sup 3} and areal density of 2.4 g=cm{sup 2} using 485 kJ of laser energy.

  3. Electro-spark deposition technology

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.N. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-12-01

    Electro-Spark Deposition (ESD) is a micro-welding process that uses short duration, high-current electrical pulses to deposit or alloy a consumable electrode material onto a metallic substrate. The ESD process was developed to produce coatings for use in severe environments where most other coatings fail. Because of the exceptional damage resistance of these coatings, and the versatility of the process to apply a wide variety of alloys, intermetallics, and cermets to metal surfaces, the ESD process has been designated critical to the life and economy of the advanced fossil energy systems as the higher temperatures and corrosive environments exceed the limits of known structural materials to accommodate the service conditions. Developments include producing iron aluminide-based coatings with triple the corrosion resistance of the best previous Fe{sub 3}Al coatings, coatings with refractory metal diffusion barriers and multi layer coatings for achieving functionally gradient properties between the substrate and the surface. A new development is the demonstration of advanced aluminide-based ESD coatings for erosion and wear applications. One of the most significant breakthroughs to occur in the last dozen years is the discovery of a process regime that yields an order of magnitude increase in deposition rates and achievable coating thicknesses. Achieving this regime has required the development of advanced ESD electronic capabilities. Development is now focused on further improvements in deposition rates, system reliability when operating at process extremes, and economic competitiveness.

  4. Automatic code generation in SPARK: Applications of computer algebra and compiler-compilers

    Energy Technology Data Exchange (ETDEWEB)

    Nataf, J.M.; Winkelmann, F.

    1992-09-01

    We show how computer algebra and compiler-compilers are used for automatic code generation in the Simulation Problem Analysis and Research Kernel (SPARK), an object oriented environment for modeling complex physical systems that can be described by differential-algebraic equations. After a brief overview of SPARK, we describe the use of computer algebra in SPARK's symbolic interface, which generates solution code for equations that are entered in symbolic form. We also describe how the Lex/Yacc compiler-compiler is used to achieve important extensions to the SPARK simulation language, including parametrized macro objects and steady-state resetting of a dynamic simulation. The application of these methods to solving the partial differential equations for two-dimensional heat flow is illustrated.

  5. Localized microwave pulsed plasmas for ignition and flame front enhancement

    Science.gov (United States)

    Michael, James Bennett

    Modern combustor technologies require the ability to match operational parameters to rapidly changing demands. Challenges include variable power output requirements, variations in air and fuel streams, the requirement for rapid and well-controlled ignition, and the need for reliability at low fuel mixture fractions. Work on subcritical microwave coupling to flames and to weakly ionized laser-generated plasmas has been undertaken to investigate the potential for pulsed microwaves to allow rapid combustion control, volumetric ignition, and leaner combustion. Two strategies are investigated. First, subcritical microwaves are coupled to femtosecond laser-generated ionization to ignite methane/air mixtures in a quasi-volumetric fashion. Total energy levels are comparable to the total minimum ignition energies for laser and spark discharges, but the combined strategy allows a 90 percent reduction in the required laser energy. In addition, well-defined multi-dimensional ignition patterns are designated with multiple laser passes. Second, microwave pulse coupling to laminar flame fronts is achieved through interaction with chemiionization-produced electrons in the reaction zone. This energy deposition remains well-localized for a single microwave pulse, resulting in rapid temperature rises of greater than 200 K and maintaining flame propagation in extremely lean methane/air mixtures. The lean flammability limit in methane/air mixtures with microwave coupling has been decreased from an equivalence ratio 0.6 to 0.3. Additionally, a diagnostic technique for laser tagging of nitrogen for velocity measurements is presented. The femtosecond laser electronic excitation tagging (FLEET) technique utilizes a 120 fs laser to dissociate nitrogen along a laser line. The relatively long-lived emission from recombining nitrogen atoms is imaged with a delayed and fast-gated camera to measure instantaneous velocities. The emission strength and lifetime in air and pure nitrogen allow

  6. Ignition Dynamic Parameters for Coke in Cement Calciners

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The mathematical ignition model was established and researches of ignition dynamic parameters for coke in some typical coal samples from cement plants was carried out according to circumstances of coal combusted in cement plants.In order to get the ignitioin temperature Tpi of carbon particles more accurately,the temperature rising experimental method was used and the actual heating circumstances for pulverized coal in calciners(in cement plants)were also considered.With this method,the accurate determination of the ignition temperature of coke in coal was achieved,so as to get some ignition dynamic parameters.These research results provide a theoretical basis for investigating coal ignition characteristics more scientifically and more accurately.

  7. Quantified infrared imaging of ignition and combustion in a supersonic flow

    Science.gov (United States)

    Ombrello, Timothy; Blunck, David L.; Resor, Michael

    2016-09-01

    The utility of quantified infrared radiation imaging was evaluated through interrogating ignition and burning processes within a cavity-based flameholder in supersonic flows. Two ignition techniques, spark discharge and pulse detonation, along with quasi-steady cavity burning were used to assess the sensitivities of measurements of radiation intensities in the infrared. The shedding of ignition kernels from the spark discharge was imaged, showing that sufficient signal-to-noise ratios can be achieved even with weak radiation emission levels. The ignition events using a pulse detonator were captured with time-resolved measurements of the plume evolution, including the barrel shock, Mach disk, and shock diamonds. Radiation emissions from subsequent firings of the pulse detonator increased, indicating that heat loss to the tube walls occurred in the early pulses. Imaging of the quasi-steady burning within the cavity demonstrated that the highest burning flux (visible broadband chemiluminescence) and radiation from hydrocarbons (3.4 µm) do not coincide with each other for the fueling strategy used. Numerical simulations provided insight into the species distributions that caused the infrared emissions. Overall, infrared radiation measurements have been shown to be feasible through combustor windows in the harsh combustion environments that were interrogated, and offer a new avenue for rapid and quantitative measurements of reactive flow.

  8. Electro-spark deposition technology

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.N. [Pacific Northwest Lab., WA (United States)

    1996-08-01

    Electro-Spark Deposition (ESD) is a micro-welding process that uses short duration, high-current electrical pulses to deposit or alloy a consumable electrode material onto a metallic substrate. The ESD process was developed to produce coatings for use in severe environments where most other coatings fail. Because of the exceptional damage resistance of these coatings, and the versatility of the process to apply a wide variety of alloys, intermetallics, and cermets to metal surfaces, the ESD process has been designated as one of the enabling technologies for advanced energy systems. Developments include producing iron aluminide-based coatings with triple the corrosion resistance of the best previous Fe{sub 3}Al coatings, coatings with refractory metal diffusion barriers and multi layer coatings for achieving functionally gradient properties between the substrate and the surface. One of the most significant breakthroughs to occur in the last dozen years is the discovery of a process regime that promises an order of magnitude increase in deposition rates and achievable coating thicknesses. Since this regime borders on and exceeds the normal operating limits of existing ESD electronic equipment, development is in progress to produce equipment that can consistently and reliably achieve these conditions for a broad range of materials. Progress so far has resulted in a consistent 500% increase in deposition rates, and greater rates still are anticipated. Technology transfer activities are a significant portion of the ESD program effort. Notable successes now include the start-up of a new business to commercialize the ESD technology, the incorporation of the process into the operations of a major gas turbine manufacturer, major new applications in gas turbine blade and steam turbine blade protection and repair, and in military, medical, metal-working, and recreational equipment applications.

  9. Exposure to electrocution by automotive ignition system in the work environment of car service employees

    Directory of Open Access Journals (Sweden)

    Bernard Fryśkowski

    2014-06-01

    Full Text Available Automotive ignition system diagnostic procedures involve a specific kind of action due to the presence of high voltage pulses rated of roughly several dozen kilovolts. Therefore, the repairers employed at car service coming into direct contact with electrical equipment of ignition systems are exposed to risk of electric shock. Typically, the electric discharge energy of automotive ignition systems is not high enough to cause fibrillation due to the electric effect on the heart. Nevertheless, there are drivers and car service employees who use electronic cardiac pacemakers susceptible to high voltage pulses. The influence of high-voltage ignition systems on the human body, especially in case of electric injury, has not been comprehensively elucidated. Therefore, relatively few scientific papers address this problem. The aim of this paper is to consider the electrical injury danger from automotive ignition systems, especially in people suffering from cardiac diseases. Some examples of the methods to reduce electric shock probability during diagnostic procedures of spark-ignition combustion engines are presented and discussed. Med Pr 2014;65(3:419–427

  10. Control and diagnosis oriented modelling of the compression ignition engine; Modelisation du moteur a allumage par compression dans la perspective du controle et du diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Grondin, O.

    2004-12-15

    This thesis has described an investigation into the modelling of compression ignition engine for control and diagnosis purpose. The Diesel engine is the most efficient and clean internal combustion engine due to modem electromechanical actuators. However, pollutant emission regulations are much more stricter, thus, these complex systems need sophisticated and efficient control algorithms to reach very low emission levels. For this task, engine models are required at each step of the control system development: control laws synthesis, simulation and validation. The system under study is a six cylinder direct injection Diesel engine fitted with a turbocharger. The model of this system is based on physical laws for some parts of the engine such as cylinders, manifolds, turbocharger and crank-slider system. In order to reduce computing time we choose to model heat transfer and heat release during combustion using simple empirical correlations. Resulting model has been implemented in the Matlab-Simulink environment and it can predict variables of interest for control purpose with one degree crank angle resolution. The model has been tested numerically and compared with an industrial engine simulation code with good results. Moreover, model output variables are in good agreement with experimental data recorded on a heavy-duty research engine. The engine model has been embedded on a board providing enough computing performances to perform real-time simulations, this will be helpful for 'hardware-in-the-loop' simulations. Another part of this study is dedicated to the combustion process modelling using a non linear phenomenological model: the NARMAX model. The goal is to predict the in-cylinder pressure evolution using other measurements available on the engine. The NARMAX model parameters have been identified using input-output data carried out from the experimental engine. Such model is well suited for real-time applications compare to numerically cost

  11. Comparative study of INPIStron and spark gap

    Science.gov (United States)

    Han, Kwang S.; Lee, Ja H.

    1993-01-01

    An inverse pinch plasma switch, INPIStron, was studied in comparison to a conventional spark gap. The INPIStron is under development for high power switching applications. The INPIStron has an inverse pinch dynamics, opposed to Z-pinch dynamics in the spark gap. The electrical, plasma dynamics and radiative properties of the closing plasmas have been studied. Recently the high-voltage pulse transfer capabilities or both the INPIStron and the spark gap were also compared. The INPIStron with a low impedance Z = 9 ohms transfers 87 percent of an input pulse with a halfwidth of 2 mu s. For the same input pulse the spark gap of Z = 100 ohms transfers 68 percent. Fast framing and streak photography, taken with an TRW image converter camera, was used to observe the discharge uniformity and closing plasma speed in both switches. In order to assess the effects of closing plasmas on erosion of electrode material, emission spectra of two switches were studied with a spectrometer-optical multi channel analyzer (OMA) system. The typical emission spectra of the closing plasmas in the INPIStron and the spark gap showed that there were comparatively weak carbon line emission in 658.7 nm and copper (electrode material) line emissions in the INPIStron, indicating low erosion of materials in the INPIStron.

  12. National Ignition Facility under fire over ignition failure

    Science.gov (United States)

    Allen, Michael

    2016-08-01

    The 3.5bn National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in California is no nearer to igniting a sustainable nuclear fusion burn - four years after its initial target date - according to a report by the US National Nuclear Security Administration (NNSA).

  13. SciSpark's SRDD : A Scientific Resilient Distributed Dataset for Multidimensional Data

    Science.gov (United States)

    Palamuttam, R. S.; Wilson, B. D.; Mogrovejo, R. M.; Whitehall, K. D.; Mattmann, C. A.; McGibbney, L. J.; Ramirez, P.

    2015-12-01

    Remote sensing data and climate model output are multi-dimensional arrays of massive sizes locked away in heterogeneous file formats (HDF5/4, NetCDF 3/4) and metadata models (HDF-EOS, CF) making it difficult to perform multi-stage, iterative science processing since each stage requires writing and reading data to and from disk. We have developed SciSpark, a robust Big Data framework, that extends ApacheTM Spark for scaling scientific computations. Apache Spark improves the map-reduce implementation in ApacheTM Hadoop for parallel computing on a cluster, by emphasizing in-memory computation, "spilling" to disk only as needed, and relying on lazy evaluation. Central to Spark is the Resilient Distributed Dataset (RDD), an in-memory distributed data structure that extends the functional paradigm provided by the Scala programming language. However, RDDs are ideal for tabular or unstructured data, and not for highly dimensional data. The SciSpark project introduces the Scientific Resilient Distributed Dataset (sRDD), a distributed-computing array structure which supports iterative scientific algorithms for multidimensional data. SciSpark processes data stored in NetCDF and HDF files by partitioning them across time or space and distributing the partitions among a cluster of compute nodes. We show usability and extensibility of SciSpark by implementing distributed algorithms for geospatial operations on large collections of multi-dimensional grids. In particular we address the problem of scaling an automated method for finding Mesoscale Convective Complexes. SciSpark provides a tensor interface to support the pluggability of different matrix libraries. We evaluate performance of the various matrix libraries in distributed pipelines, such as Nd4jTM and BreezeTM. We detail the architecture and design of SciSpark, our efforts to integrate climate science algorithms, parallel ingest and partitioning (sharding) of A-Train satellite observations from model grids. These

  14. Implosion Hydrodynamics of Fast Ignition Targets

    Science.gov (United States)

    Stephens, R. B.

    2004-11-01

    The fast ignition (FI) concept requires the generation of a compact, dense, pure fuel mass accessible to an external ignition source. The current baseline FI target is a shell fitted with a reentrant cone extending to near its center. Conventional direct or indirect drive collapses the shell near the tip of the cone and then an ultra-intense laser pulse focused to the inside cone tip generates high-energy electrons to ignite the dense fuel. We have theoretically and experimentally investigated the collapse of such targets, validating modeling and exploring the tradeoffs available, in such an asymmetric geometry, to optimize compaction of the fuel and maintain the integrity of the cone. The collapse is complex. Away from the cone, the shell collapses much as does a conventional implosion, generating a hot, low-density inner core. But because of the open side this hot plasma exhausts out toward the tip of the cone. This hot plasma is advantageous for implosion diagnostics; it can provide protons for angular dependent measurements of the shell wall, neutrons for temperature measurements, and self-emission for contamination measurements. But the hot spot must be controlled; for FI it is a liability. The hot, low-density inner core simply impedes the collapse of the cold fuel, lowering the implosion/burn efficiency and the gain while making ignition more difficult. We discuss approaches to minimizing this effect and experimental tests.

  15. Plastic ablator ignition capsule design for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D S; Haan, S W; Hammel, B A; Salmonson, J D; Callahan, D A; Town, R P

    2009-12-01

    The National Ignition Campaign, tasked with designing and fielding targets for fusion ignition experiments on the National Ignition Facility (NIF), has carried forward three complementary target designs for the past several years: a beryllium ablator design, a plastic ablator design, and a high-density carbon or synthetic diamond design. This paper describes current simulations and design optimization to develop the plastic ablator capsule design as a candidate for the first ignition attempt on NIF. The trade-offs in capsule scale and laser energy that must be made to achieve a comparable ignition probability to that with beryllium are emphasized. Large numbers of 1-D simulations, meant to assess the statistical behavior of the target design, as well as 2-D simulations to assess the target's susceptibility to Rayleigh-Taylor growth are presented.

  16. Management of auxiliary aggregates - development and testing of methods for improved use of auxiliary aggregates of diesel and spark ignition engines in stationary and unstationary operation. Final report; Nebenaggregate-Management - Entwicklung und Erprobung von Verfahren zum verbesserten Einsatz der Nebenaggregate an Diesel- und Ottomotoren bei stationaerem und instationaerem Betrieb. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, M.; Lenzen, B.; Groef, S.; Isermann, R. [Technische Univ. Darmstadt (Germany). Inst. fuer Regelungstechnik; Hohenberg, G. [Technische Univ. Darmstadt (Germany). Fachgebiet Verbrennungskraftmaschinen

    1998-07-01

    Aggregate management is aimed at aggregate operation in consideration of demand, consumption and exhaust. Demands on reliability are high. Investigations were made using modelling, simulation, model reduction and identification, with the focus on model reduction. The resulting concepts for consumption reduction vary depending on the vehicle type and application. [German] Das Nebenaggregate-Management hat den bedarfs-, verbrauchs- und abgasorientierten Betrieb der Nebenaggregate im Kraftfahrzeug zum Ziel. Der sehr weit gespannte Einsatzbereich von Kraftfahrzeugen und die hohen Anforderungen an die Betriebszuverlaessigkeit stellen entsprechende Anforderungen an das Management. Zur Untersuchung eines verbesserten Betriebs von Nebenaggregaten wrden Verfahren der Regelungstechnik wie z.B. Modellbildung, Simulation, Modellreduktion und Identifikation eingesetzt, wobei der Modellreduktion in anbetracht des komplexen Gesamtsystems Kraftfahrzeug eine besondere Bedeutung zukommt. Ergebnisse der Untersuchungen sind Konzepte zur Verringerung des Verbrauchsanteils der Nebenaggregate, die je nach Fahrzeugtyp und Einsatzzweck variieren. (orig.)

  17. 发动机火花塞积碳问题分析及解决措施%Analysis and Solution to Carbon Deposition of Engine Spark Plug

    Institute of Scientific and Technical Information of China (English)

    付雪超; 马文亮; 李慧军; 由毅

    2013-01-01

    某车型搭载的1.0L自然吸气式发动机在使用中出现火花塞积碳的问题.为解决此问题,笔者详细分析了可能造成火花塞积碳的原因,并通过试验对比的手段进行了逐一验证.结果表明,造成积碳的原因是火花塞点火能量、工作状态温度偏低,形成的积碳不能燃烧掉.针对该故障原因,提出了延长点火线圈充电时间、优化火花塞尺寸的方案,以提高火花塞点火能量及工作温度.经试验验证,该方案能有效解决火花塞积碳的问题.%The carbon deposition of spark plug for a 1.0L naturally-aspirated engine is found with regard to a specific car on the market.To solve this problem,the cause of carbon deposition of spark plug is particularly analyzed in this article.Furthermore,the validation is performed one by one through test comparison.The result indicates that the carbon deposition attributes to lower ignition energy and operating-state temperature in respect of spark plug,thus leading to non-burning of carbon deposition.In terms of this failure cause,the solution to extend charge time of ignition coil and optimize plug dimensions is presented to enhance the ignition energy of spark plug and operating temperature.This solution can significantly solve the carbon deposition of spark plug via test validation.

  18. Spark - a modern approach for distributed analytics

    CERN Document Server

    CERN. Geneva; Kothuri, Prasanth

    2016-01-01

    The Hadoop ecosystem is the leading opensource platform for distributed storing and processing big data. It is a very popular system for implementing data warehouses and data lakes. Spark has also emerged to be one of the leading engines for data analytics. The Hadoop platform is available at CERN as a central service provided by the IT department. By attending the session, a participant will acquire knowledge of the essential concepts need to benefit from the parallel data processing offered by Spark framework. The session is structured around practical examples and tutorials. Main topics: Architecture overview - work distribution, concepts of a worker and a driver Computing concepts of transformations and actions Data processing APIs - RDD, DataFrame, and SparkSQL

  19. Simple model of the indirect compression of targets under conditions close to the national ignition facility at an energy of 1.5 MJ

    Energy Technology Data Exchange (ETDEWEB)

    Rozanov, V. B., E-mail: rozanov@sci.lebedev.ru; Vergunova, G. A., E-mail: verg@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2015-11-15

    The possibility of the analysis and interpretation of the reported experiments with the megajoule National Ignition Facility (NIF) laser on the compression of capsules in indirect-irradiation targets by means of the one-dimensional RADIAN program in the spherical geometry has been studied. The problem of the energy balance in a target and the determination of the laser energy that should be used in the spherical model of the target has been considered. The results of action of pulses differing in energy and time profile (“low-foot” and “high-foot” regimes) have been analyzed. The parameters of the compression of targets with a high-density carbon ablator have been obtained. The results of the simulations are in satisfactory agreement with the measurements and correspond to the range of the observed parameters. The set of compared results can be expanded, in particular, for a more detailed determination of the parameters of a target near the maximum compression of the capsule. The physical foundation of the possibility of using the one-dimensional description is the necessity of the closeness of the last stage of the compression of the capsule to a one-dimensional process. The one-dimensional simulation of the compression of the capsule can be useful in establishing the boundary behind which two-dimensional and three-dimensional simulation should be used.

  20. Experimental and Modeling Investigation of the Effectof H2S Addition to Methane on the Ignition and Oxidation at High Pressures

    DEFF Research Database (Denmark)

    Gersen, Sander; van Essen, Martijn; Darmeveil, Harry;

    2016-01-01

    The autoignition and oxidation behavior of CH4/H2S mixtures has been studied experimentally in a rapid compression machine (RCM) and a high-pressure flow reactor. The RCM measurements show that the addition of 1% H2S to methane reduces the autoignition delay time by a factor of 2 at pressures...... ranging from 30 to 80 bar and temperatures from 930 to 1050 K. The flow reactor experiments performed at 50 bar show that, for stoichiometric conditions,a large fraction of H2S is already consumed at 600 K, while temperatures above 750 K are needed to oxidize 10% methane. A detailed chemical kinetic model...... has been established, describing the oxidation of CH4 and H2S as well as the formation and consumption of organo sulfuric species. Computations with the modelshow good agreement with the ignition measurements, provided that reactions of H2S and SH with peroxides (HO2 and CH3OO) are constrained...

  1. Experimental and Modeling Investigation of the Effectof H2S Addition to Methane on the Ignition and Oxidation at High Pressures

    DEFF Research Database (Denmark)

    Gersen, Sander; van Essen, Martijn; Darmeveil, Harry

    2017-01-01

    The autoignition and oxidation behavior of CH4/H2S mixtures has been studied experimentally in a rapid compression machine (RCM) and a high-pressure flow reactor. The RCM measurements show that the addition of 1% H2S to methane reduces the autoignition delay time by a factor of 2 at pressures...... ranging from 30 to 80 bar and temperatures from 930 to 1050 K. The flow reactor experiments performed at 50 bar show that, for stoichiometric conditions,a large fraction of H2S is already consumed at 600 K, while temperatures above 750 K are needed to oxidize 10% methane. A detailed chemical kinetic model...... has been established, describing the oxidation of CH4 and H2S as well as the formation and consumption of organo sulfuric species. Computations with the modelshow good agreement with the ignition measurements, provided that reactions of H2S and SH with peroxides (HO2 and CH3OO) are constrained...

  2. Simple model of the indirect compression of targets under conditions close to the national ignition facility at an energy of 1.5 MJ

    Science.gov (United States)

    Rozanov, V. B.; Vergunova, G. A.

    2015-11-01

    The possibility of the analysis and interpretation of the reported experiments with the megajoule National Ignition Facility (NIF) laser on the compression of capsules in indirect-irradiation targets by means of the one-dimensional RADIAN program in the spherical geometry has been studied. The problem of the energy balance in a target and the determination of the laser energy that should be used in the spherical model of the target has been considered. The results of action of pulses differing in energy and time profile ("low-foot" and "high-foot" regimes) have been analyzed. The parameters of the compression of targets with a high-density carbon ablator have been obtained. The results of the simulations are in satisfactory agreement with the measurements and correspond to the range of the observed parameters. The set of compared results can be expanded, in particular, for a more detailed determination of the parameters of a target near the maximum compression of the capsule. The physical foundation of the possibility of using the one-dimensional description is the necessity of the closeness of the last stage of the compression of the capsule to a one-dimensional process. The one-dimensional simulation of the compression of the capsule can be useful in establishing the boundary behind which two-dimensional and three-dimensional simulation should be used.

  3. Engine modeling and control modeling and electronic management of internal combustion engines

    CERN Document Server

    Isermann, Rolf

    2014-01-01

    The increasing demands for internal combustion engines with regard to fuel consumption, emissions and driveability lead to more actuators, sensors and complex control functions. A systematic implementation of the electronic control systems requires mathematical models from basic design through simulation to calibration. The book treats physically-based as well as models based experimentally on test benches for gasoline (spark ignition) and diesel (compression ignition) engines and uses them for the design of the different control functions. The main topics are: - Development steps for engine control - Stationary and dynamic experimental modeling - Physical models of intake, combustion, mechanical system, turbocharger, exhaust, cooling, lubrication, drive train - Engine control structures, hardware, software, actuators, sensors, fuel supply, injection system, camshaft - Engine control methods, static and dynamic feedforward and feedback control, calibration and optimization, HiL, RCP, control software developm...

  4. Ignition and Inertial Confinement Fusion at The National Ignition Facility

    Science.gov (United States)

    Moses, Edward I.

    2016-10-01

    The National Ignition Facility (NIF), the world's largest and most powerful laser system for inertial confinement fusion (ICF) and for studying high-energy-density (HED) science, is now operational at Lawrence Livermore National Laboratory (LLNL). The NIF is now conducting experiments to commission the laser drive, the hohlraum and the capsule and to develop the infrastructure needed to begin the first ignition experiments in FY 2010. Demonstration of ignition and thermonuclear bum in the laboratory is a major NIF goal. NIF will achieve this by concentrating the energy from the 192 beams into a mm3-sized target and igniting a deuterium-tritium mix, liberating more energy than is required to initiate the fusion reaction. NIP's ignition program is a national effort managed via the National Ignition Campaign (NIC). The NIC has two major goals: execution of DT ignition experiments starting in FY20l0 with the goal of demonstrating ignition and a reliable, repeatable ignition platform by the conclusion of the NIC at the end of FY2012. The NIC will also develop the infrastructure and the processes required to operate NIF as a national user facility. The achievement of ignition at NIF will demonstrate the scientific feasibility of ICF and focus worldwide attention on laser fusion as a viable energy option. A laser fusion-based energy concept that builds on NIF, known as LIFE (Laser Inertial Fusion Energy), is currently under development. LIFE is inherently safe and can provide a global carbon-free energy generation solution in the 21st century. This paper describes recent progress on NIF, NIC, and the LIFE concept.

  5. High performance Spark best practices for scaling and optimizing Apache Spark

    CERN Document Server

    Karau, Holden

    2017-01-01

    Apache Spark is amazing when everything clicks. But if you haven’t seen the performance improvements you expected, or still don’t feel confident enough to use Spark in production, this practical book is for you. Authors Holden Karau and Rachel Warren demonstrate performance optimizations to help your Spark queries run faster and handle larger data sizes, while using fewer resources. Ideal for software engineers, data engineers, developers, and system administrators working with large-scale data applications, this book describes techniques that can reduce data infrastructure costs and developer hours. Not only will you gain a more comprehensive understanding of Spark, you’ll also learn how to make it sing. With this book, you’ll explore: How Spark SQL’s new interfaces improve performance over SQL’s RDD data structure The choice between data joins in Core Spark and Spark SQL Techniques for getting the most out of standard RDD transformations How to work around performance issues i...

  6. Optical diagnostics integrated with laser spark delivery system

    Science.gov (United States)

    Yalin, Azer; Willson, Bryan; Defoort, Morgan; Joshi, Sachin; Reynolds, Adam

    2008-09-02

    A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

  7. Effect of Various Ignition Timings on Combustion Process and Performance of Gasoline Engine

    Directory of Open Access Journals (Sweden)

    Lukáš Tunka

    2017-01-01

    Full Text Available This article deals with the effect of the ignition timing on the output parameters of a spark-ignition engine. The main assessed parameters include the output parameters of the engine (engine power and torque, cylinder pressure variation, heat generation and burn rate. However, the article also discusses the effect of the ignition timing on the temperature of exhaust gases, the indicated mean effective pressure, the combustion duration, combustion stability, etc. All measurements were performed in an engine test room in the Department of Technology and Automobile Transport at Mendel University in Brno, on a four-cylinder AUDI engine with a maximum power of 110 kW, as indicated by the manufacturer. To control and change the ignition timing of the engine, a fully programmable Magneti Marelli control unit was used. The experimental measurements were performed on 8 different ignition timings, from 18 °CA to 32 °CA BTDC at wide throttle open and a constant engine speed (2500 rpm, with a stoichiometric mixture fraction. The measurement results showed that as the ignition timing increases, the engine power and torque also increase. The increase in these parameters is a reflection of higher pressure in the cylinder, the maximum value of which is achieved at a higher ignition timing near top dead centre in thepower stroke. In these conditions we can expect higher engine efficiency. It was also found that the combustion is more stable with a higher value of ignition timing. No significant difference was found in the combustion duration.

  8. IMPROVEMENT TO PIPELINE COMPRESSOR ENGINE RELIABILITY THROUGH RETROFIT MICRO-PILOT IGNITION SYSTEM-PHASE I

    Energy Technology Data Exchange (ETDEWEB)

    Ted Bestor

    2003-03-04

    This report documents the first year's effort towards a 3-year program to develop micropilot ignition systems for existing pipeline compressor engines. In essence, all Phase I goals and objectives were met. We intend to proceed with the Phase II research plan, as set forth by the applicable Research Management Plan. The objective for Phase I was to demonstrate the feasibility of micropilot ignition for large bore, slow speed engines operating at low compression ratios. The primary elements of Micropilot Phase I were to develop a single-cylinder test chamber to study the injection of pilot fuel into a combustion cylinder and to develop, install and test a multi-cylinder micropilot ignition system for a 4-cylinder, natural gas test engine. In all, there were twelve (12) tasks defined and executed to support these two (2) primarily elements in a stepwise fashion. Task-specific approaches and results are documented in this report. Research activities for Micropilot Phase I were conducted with the understanding that the efforts are expected to result in a commercial product to capture and disseminate the efficiency and environmental benefits of this new technology. An extensive state-of-art review was conducted to leverage the existing body of knowledge of micropilot ignition with respect to retrofit applications. Additionally, commercially-available fuel injection products were identified and applied to the program where appropriate. This approach will minimize the overall time-to-market requirements, while meeting performance and cost criteria. The four-cylinder prototype data was encouraging for the micro-pilot ignition technology when compared to spark ignition. Initial testing results showed: (1) Brake specific fuel consumption of natural gas was improved from standard spark ignition across the map, 1% at full load and 5% at 70% load. (2) 0% misfires for all points on micropilot ignition. Fuel savings were most likely due to this percent misfire improvement

  9. Laser-plasma interactions for fast ignition

    CERN Document Server

    Kemp, A J; Debayle, A; Johzaki, T; Mori, W B; Patel, P K; Sentoku, Y; Silva, L O

    2013-01-01

    In the electron-driven fast-ignition approach to inertial confinement fusion, petawatt laser pulses are required to generate MeV electrons that deposit several tens of kilojoules in the compressed core of an imploded DT shell. We review recent progress in the understanding of intense laser plasma interactions (LPI) relevant to fast ignition. Increases in computational and modeling capabilities, as well as algorithmic developments have led to enhancement in our ability to perform multi-dimensional particle-in-cell (PIC) simulations of LPI at relevant scales. We discuss the physics of the interaction in terms of laser absorption fraction, the laser-generated electron spectra, divergence, and their temporal evolution. Scaling with irradiation conditions such as laser intensity are considered, as well as the dependence on plasma parameters. Different numerical modeling approaches and configurations are addressed, providing an overview of the modeling capabilities and limitations. In addition, we discuss the compa...

  10. Type Ia supernova diversity in three-dimensional delayed detonation models from variations in the central white dwarf density at ignition

    CERN Document Server

    Seitenzahl, I R; Roepke, F K

    2010-01-01

    Delayed detonations of Chandrasekhar-mass white dwarfs (WDs) have been very successful in explaining the spectra, light curves, and the width-luminosity relation of spectroscopically normal Type Ia supernovae (SNe Ia). The ignition of the thermonuclear deflagration flame at the end of the convective carbon "simmering" phase in the core of the WD is still not well understood and much about the ignition kernel distribution remains unknown. Furthermore, the central density at the time of ignition depends on the still uncertain screened carbon fusion reaction rates, the accretion history and cooling time of the progenitor, and the composition. We present the results of twelve high-resolution three-dimensional delayed detonation SN Ia explosion simulations that employ a new criterion to trigger the deflagration to detonation transition (DDT). All simulations trigger our DDT criterion and the resulting delayed detonations unbind the star. We find a trend of increasing iron group element (IGE) production with increa...

  11. Vaporization of atherosclerotic plaques by spark erosion

    NARCIS (Netherlands)

    C.J. Slager (Cornelis); C.E. Essed; J.C.H. Schuurbiers (Johan); N. Bom (Klaas); P.W.J.C. Serruys (Patrick); G.T. Meester (Geert)

    1985-01-01

    textabstractAn alternative to the laser irradiation of atherosclerotic lesions has been developed. A pulsed electrocardiogram R wave-triggered electrical spark erosion technique is described. Controlled vaporization of fibrous and lipid plaques with minimal thermal side effects was achieved and docu

  12. Generation of Nanoparticles by Spark Discharge

    NARCIS (Netherlands)

    Salman Tabrizi, N.

    2009-01-01

    Spark discharge is a method for producing nanoparticles from conductive materials. Besides the general advantages of nanoparticle synthesis in the gas phase, the method offers additional advantages like simplicity, compactness and versatility. The synthesis process is continuous and is performed at

  13. Generation of Nanoparticles by Spark Discharge

    NARCIS (Netherlands)

    Salman Tabrizi, N.

    2009-01-01

    Spark discharge is a method for producing nanoparticles from conductive materials. Besides the general advantages of nanoparticle synthesis in the gas phase, the method offers additional advantages like simplicity, compactness and versatility. The synthesis process is continuous and is performed at

  14. Ignition transient analysis of solid rocket motor

    Science.gov (United States)

    Han, Samuel S.

    1991-01-01

    Measurement data on the performance of Space Shuttle Solid Rocket Motor show wide variations in the head-end pressure changes and the total thrust build-up during the ignition transient periods. To analyze the flow and thermal behavior in the tested solid rocket motors, a 1-dimensional, ideal gas flow model via the SIMPLE algorithm was developed. Numerical results showed that burning patterns in the star-shaped head-end segment of the propellant and the erosive burning rate are two important factors controlling the ignition transients. The objective of this study is to extend the model to include the effects of aluminum particle commonly used in solid propellants. To treat the effects of aluminum-oxide particles in the combustion gas, conservation of mass, momentum, and energy equations for the particles are added in the numerical formulation and integrated by an inter-phase-slip algorithm.

  15. Three-Dimensional Models for Analyzing the Cyclic Variations in a Lean Burn CNG Engine

    Institute of Scientific and Technical Information of China (English)

    LI Guo-xiu; YU Yu-song; LIU Jian-ying

    2007-01-01

    Three-dimensional models, consisting of the flame kernel formation model, flame kernel development model and natural gas single step reaction model, are used to analyze the contribution of cyclic equivalence ratio variations to cyclic variations in the compressed natural gas (CNG) lean burn spark ignition engine. Computational results including the contributions of equivalence ratio cyclic variations to each combustion stage and effects of engine speed to the extent of combustion variations are discussed. It is concluded that the equivalence ratio variations affect mostly the main stage of combustion and hardly influence initial kernel development stage.

  16. Modeling of heat release and emissions from droplet combustion of multi component fuels in compression ignition engines

    DEFF Research Database (Denmark)

    Ivarsson, Anders

    are weakly luminous. Second main topic of the project was to enable valid temperature measurements of sooting flames. A thermometry method based on IR emission and absorption by CO2 between 2100 and 2400 cm-1 was developed specifically for pre-mixed flat flames. Detection was performed with a commercial FT...... and shape of the unstable sooting flame. The stable cases were easier to treat both experimentally and numerically, and were used for more detailed validation. The model was developed stepwise from the simplest possible starting point. The first part of the development was made on a model of thermal fluid...

  17. Investigation on minimum ignition energy of mixtures of α-pinene-benzene/air.

    Science.gov (United States)

    Coudour, B; Chetehouna, K; Rudz, S; Gillard, P; Garo, J P

    2015-01-01

    Minimum ignition energies (MIE) of α-pinene-benzene/air mixtures at a given temperature for different equivalence ratios and fuel proportions are experimented in this paper. We used a cylindrical chamber of combustion using a nanosecond pulse at 1,064 nm from a Q-switched Nd:YAG laser. Laser-induced spark ignitions were studied for two molar proportions of α-pinene/benzene mixtures, respectively 20-80% and 50-50%. The effect of the equivalence ratio (Φ) has been investigated for 0.7, 0.9, 1.1 and 1.5 and ignition of fuel/air mixtures has been experimented for two different incident laser energies: 25 and 33 mJ. This study aims at observing the influence of different α-pinene/benzene proportions on the flammability of the mixture to have further knowledge of the potential of biogenic volatile organic compounds (BVOCs) and smoke mixtures to influence forest fires, especially in the case of the accelerating forest fire phenomenon (AFF). Results of ignition probability and energy absorption are based on 400 laser shots for each studied fuel proportions. MIE results as functions of equivalence ratio compared to data of pure α-pinene and pure benzene demonstrate that the presence of benzene in α-pinene-air mixture tends to increase ignition probability and reduce MIE without depending strongly on the α-pinene/benzene proportion.

  18. 3D measurements of ignition processes at 20 kHz in a supersonic combustor

    Science.gov (United States)

    Ma, Lin; Lei, Qingchun; Wu, Yue; Ombrello, Timothy M.; Carter, Campbell D.

    2015-05-01

    The ignition dynamics in a Mach 2 combustor were investigated using a three-dimensional (3D) diagnostic with 20 kHz temporal resolution. The diagnostic was based on a combination of tomographic chemiluminescence and fiber-based endoscopes (FBEs). Customized FBEs were employed to capture line-of-sight integrated chemiluminescence images (termed projections) of the combustor from eight different orientations simultaneously at 20 kHz. The measured projections were then used in a tomographic algorithm to obtain 3D reconstruction of the sparks, ignition kernel, and stable flame. Processing the reconstructions frame by frame resulted in 4D measurements. Key properties were then extracted to quantify the ignition processes, including 3D volume, surface area, sphericity, and velocity of the ignition kernel. The data collected in this work revealed detailed spatiotemporal dynamics of the ignition kernel, which are not obtainable with planar diagnostics, such as its growth, movement, and development into "stable" combustion. This work also illustrates the potential for obtaining quantitative 3D measurements using tomographic techniques and the practical utility of FBEs.

  19. Self-ignition and ignition of aluminum powders in shock waves

    Science.gov (United States)

    Boiko, V. M.; Poplavski, S. V.

    Ignition of fine aluminum powders in reflected shock waves has been studied. Two ignition regimes are found: self-ignition observed at temperatures higher than 1800 K and ``low-temperature'' ignition at temperatures of 1000-1800 K. The possibility of initiating the ignition of aluminum powders in air using combustible liquids has been studied too.

  20. Possible version of the compression degradation of the thermonuclear indirect-irradiation targets at the national ignition facility and a reason for the failure of ignition

    Energy Technology Data Exchange (ETDEWEB)

    Rozanov, V. B., E-mail: rozanov@sci.lebedev.ru; Vergunova, G. A., E-mail: verg@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2017-01-15

    The main parameters of compression of a target and tendencies at change in the irradiation conditions are determined by analyzing the published results of experiments at the megajoule National Ignition Facility (NIF) on the compression of capsules in indirect-irradiation targets by means of the one-dimensional RADIAN program in the spherical geometry. A possible version of the “failure of ignition” of an indirect-irradiation target under the NIF conditions is attributed to radiation transfer. The application of onedimensional model to analyze the National Ignition Campaign (NIC) experiments allows identifying conditions corresponding to the future ignition regime and distinguishing them from conditions under which ignition does not occur.