Air-fuel ratio control of a lean burn Si engine using fuzzy self tuning method

International Nuclear Information System (INIS)

Akhlaghi, M.; Bakhtiari Nejad, F.; Azadi, S.

2000-01-01

Reducing the exhaust emission of an spark ignition engine by means of engine modifications requires consideration of the effects of these modifications on the variations of crankshaft torque and the engine roughness respectively. Only if the roughness does not exceed a certain level the vehicle do not begin to surge. This paper presents a method for controlling the air-fuel ratio for a lean burn engine. Fuzzy rules and reasoning are utilized on-line to determine the control parameters. The main advantages of this method are simple structure and robust performance in a wide range of operating conditions. A non-linear model of an Si engine with the engine torque irregularity simulation is used in this study

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.

Alternative Observers for SI Engine Air/Fuel Ratio Control

DEFF Research Database (Denmark)

Hendricks, Elbert; Poulsen, Jannik; Olsen, Mads Bruun

1996-01-01

In earlier work it has been shown that a nonlinear observer based on the use of the manifold pressure state equation and a nonlinear fuel film compensator can maintain accurate A/F ratio control during both steady state and transient operation. This observer may be called a manifold absolute pres...... engine control system designer with a variety of robust control systems which can easily be made redundant in order to satisfy newer engine emissions and diagnosis requirements and legislation...

Tracer-based laser-induced fluorescence measurement technique for quantitative fuel/air-ratio measurements in a hydrogen internal combustion engine.

Science.gov (United States)

Blotevogel, Thomas; Hartmann, Matthias; Rottengruber, Hermann; Leipertz, Alfred

2008-12-10

A measurement technique for the quantitative investigation of mixture formation processes in hydrogen internal combustion engines (ICEs) has been developed using tracer-based laser-induced fluorescence (TLIF). This technique can be employed to fired and motored engine operation. The quantitative TLIF fuel/air-ratio results have been verified by means of linear Raman scattering measurements. Exemplary results of the simultaneous investigation of mixture formation and combustion obtained at an optical accessible hydrogen ICE are shown.

A phenomenological model of two-phase (air/fuel droplet developing and breakup

Directory of Open Access Journals (Sweden)

Pavlović Radomir R.

2013-01-01

Full Text Available Effervescent atomization namely the air-filled liquid atomization comprehends certain complex two-phase phenomenon that are difficult to be modeled. Just a few researchers have found the mathematical expressions for description of the complex atomization model of the two-phase mixture air/diesel fuel. In the following review, developing model of twophase (air/fuel droplet of Cummins spray pump-injector is shown. The assumption of the same diameters of the droplet and the opening of the atomizer is made, while the air/fuel mass ratio inside the droplet varies.

Knock-Limited Performance of Triptane and 28-R Fuel Blends as Affected by Changes in Compression Ratio and in Engine Operating Variables

Science.gov (United States)

Brun, Rinaldo J.; Feder, Melvin S.; Fisher, William F.

1947-01-01

A knock-limited performance investigation was conducted on blends of triptane and 28-P fuel with a 12-cylinder, V-type, liquid-cooled aircraft engine of 1710-cubic-inch displacement at three compression ratios: 6.65, 7.93, and 9.68. At each compression ratio, the effect of changes in temperature of the inlet air to the auxiliary-stage supercharger and in fuel-air ratio were investigated at engine speeds of 2280 and. 3000 rpm. The results show that knock-limited engine performance, as improved by the use of triptane, allowed operation at both take-off and cruising power at a compression ratio of 9.68. At an inlet-air temperature of 60 deg F, an engine speed of 3000 rpm ; and a fuel-air ratio of 0,095 (approximately take-off conditions), a knock-limited engine output of 1500 brake horsepower was possible with 100-percent 28-R fuel at a compression ratio of 6.65; 20-percent triptane was required for the same power output at a compression ratio of 7.93, and 75 percent at a compression ratio of 9.68 allowed an output of 1480 brake horsepower. Knock-limited power output was more sensitive to changes in fuel-air ratio as the engine speed was increased from 2280 to 3000 rpm, as the compression ratio is raised from 6.65 to 9.68, or as the inlet-air temperature is raised from 0 deg to 120 deg F.

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

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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.

Estimation of Individual Cylinder Air-Fuel Ratio in Gasoline Engine with Output Delay

Directory of Open Access Journals (Sweden)

Changhui Wang

2016-01-01

Full Text Available The estimation of the individual cylinder air-fuel ratio (AFR with a single universal exhaust gas oxygen (UEGO sensor installed in the exhaust pipe is an important issue for the cylinder-to-cylinder AFR balancing control, which can provide high-quality torque generation and reduce emissions in multicylinder engine. In this paper, the system dynamic for the gas in exhaust pipe including the gas mixing, gas transport, and sensor dynamics is described as an output delay system, and a new method using the output delay system observer is developed to estimate the individual cylinder AFR. With the AFR at confluence point augmented as a system state, an observer for the augmented discrete system with output delay is designed to estimate the AFR at confluence point. Using the gas mixing model, a method with the designed observer to estimate the individual cylinder AFR is presented. The validity of the proposed method is verified by the simulation results from a spark ignition gasoline engine from engine software enDYNA by Tesis.

Minimum Specific Fuel Consumption of a Liquid-Cooled Multicylinder Aircraft Engine as Affected by Compression Ratio and Engine Operating Conditions

Science.gov (United States)

Brun, Rinaldo J.; Feder, Melvin S.; Harries, Myron L.

1947-01-01

An investigation was conducted on a 12-cylinder V-type liquid-cooled aircraft engine of 1710-cubic-inch displacement to determine the minimum specific fuel consumption at constant cruising engine speed and compression ratios of 6.65, 7.93, and 9.68. At each compression ratio, the effect.of the following variables was investigated at manifold pressures of 28, 34, 40, and 50 inches of mercury absolute: temperature of the inlet-air to the auxiliary-stage supercharger, fuel-air ratio, and spark advance. Standard sea-level atmospheric pressure was maintained at the auxiliary-stage supercharger inlet and the exhaust pressure was atmospheric. Advancing the spark timing from 34 deg and 28 deg B.T.C. (exhaust and intake, respectively) to 42 deg and 36 deg B.T.C. at a compression ratio of 6.65 resulted in a decrease of approximately 3 percent in brake specific fuel consumption. Further decreases in brake specific fuel consumption of 10.5 to 14.1 percent (depending on power level) were observed as the compression ratio was increased from 6.65 to 9.68, maintaining at each compression ratio the spark advance required for maximum torque at a fuel-air ratio of 0.06. This increase in compression ratio with a power output of 0.585 horsepower per cubic inch required a change from . a fuel- lend of 6-percent triptane with 94-percent 68--R fuel at a compression ratio of 6.65 to a fuel blend of 58-percent, triptane with 42-percent 28-R fuel at a compression ratio of 9.68 to provide for knock-free engine operation. As an aid in the evaluation of engine mechanical endurance, peak cylinder pressures were measured on a single-cylinder engine at several operating conditions. Peak cylinder pressures of 1900 pounds per square inch can be expected at a compression ratio of 9.68 and an indicated mean effective pressure of 320 pounds per square inch. The engine durability was considerably reduced at these conditions.

The effects of air stoichiometry and air excess ratio on the transient response of a PEMFC under load change conditions

International Nuclear Information System (INIS)

Kim, Bosung; Cha, Dowon; Kim, Yongchan

2015-01-01

Highlights: • Effects of controlling parameters on the transient response of a PEMFC are studied. • The transient response is measured by varying air stoichiometry and air excess ratio. • Voltage drop, undershoot, and voltage fluctuation are analyzed under the load change. • Optimal air stoichiometry and air excess ratio are suggested for stable operation. - Abstract: The transient response of a proton exchange membrane fuel cell (PEMFC) is an important issue for transportation applications. The objective of this study is to investigate the effects of operating and controlling parameters on the transient response of a PEMFC for achieving more stable cell performance under load change conditions. The transient response of a PEMFC was measured and analyzed by varying air stoichiometry, air humidity, and air excess ratio (AER). The optimal air stoichiometry and AER were determined to minimize the voltage drop, undershoot, and voltage fluctuation under the load change, while maintaining high cell performance. Based on the present data, the optimal air stoichiometry was determined to be between 2.0 and 2.5, and the optimal AER was suggested to be between 1.65 and 2.0

An Investigation of the Composition of the Flow in and out of a Two-Stroke Diesel Engine and Air Consumption Ratio

Directory of Open Access Journals (Sweden)

Mirko Grljušić

2017-06-01

Full Text Available The aim of this research was to investigate the mass, substance and energy flow through two-stroke low speed Diesel engines. For this reason, a zero-dimensional model of the combustion in the engine was developed with a calculated amount and composition of exhaust gases. Due to the large amount of oxygen in the exhaust gases, a ratio of real air consumption and stoichiometric amount of air required for combustion of injected fuel was set. The calculated ratio showed that the engine consumed four times more air than needed for combustion in AFRstoich. In this work, this was called the Air Consumption Factor or Ratio, and has not previously been mentioned in scientific literature. The air consumption ratio is defined as a factor of dry or humid air. To be more comprehensive, a modified diagram of the composition of the flow in and out of a two-stroke fuel injection engine and the cylinder was made.

Air-cooled, hydrogen-air fuel cell

Science.gov (United States)

Shelekhin, Alexander B. (Inventor); Bushnell, Calvin L. (Inventor); Pien, Michael S. (Inventor)

1999-01-01

An air-cooled, hydrogen-air solid polymer electrolyte (SPE) fuel cell with a membrane electrode assembly operatively associated with a fluid flow plate having at least one plate cooling channel extending through the plate and at least one air distribution hole extending from a surface of the cathode flow field into the plate cooling channel.

Comparison of Fuel-Nox Formation Characteristics in Conventional Air and Oxy fuel Combustion Conditions

International Nuclear Information System (INIS)

Woo, Mino; Park, Kweon Ha; Choi, Byung Chul

2013-01-01

Nitric oxide (NO x ) formation characteristics in non-premixed diffusion flames of methane fuels have been investigated experimentally and numerically by adding 10% ammonia to the fuel stream, according to the variation of the oxygen ratio in the oxidizer with oxygen/carbon dioxide and oxygen/nitrogen mixtures. In an experiment of co flow jet flames, in the case of an oxidizer with oxygen/carbon dioxide, the NO x emission increased slightly as the oxygen ratio increased. On the other hand, in case of an oxygen/nitrogen oxidizer, the NO x emission was the maximum at an oxygen ratio of 0.7, and it exhibited non-monotonic behavior according to the oxygen ratio. Consequently, the NO x emission in the condition of oxy fuel combustion was overestimated as compared to that in the condition of conventional air combustion. To elucidate the characteristics of NO x formation for various oxidizer compositions, 1a and 2a numerical simulations have been conducted by adopting one kinetic mechanism. The result of 2 simulation for an oxidizer with oxygen/nitrogen well predicted the trend of experimentally measured NO x emissions

Internal combustion engine cylinder-to-cylinder balancing with balanced air-fuel ratios

Science.gov (United States)

Harris, Ralph E.; Bourn, Gary D.; Smalley, Anthony J.

2006-01-03

A method of balancing combustion among cylinders of an internal combustion engine. For each cylinder, a normalized peak firing pressure is calculated as the ratio of its peak firing pressure to its combustion pressure. Each cylinder's normalized peak firing pressure is compared to a target value for normalized peak firing pressure. The fuel flow is adjusted to any cylinder whose normalized peak firing pressure is not substantially equal to the target value.

Analysis of the moderating ratio in BWR fuels

International Nuclear Information System (INIS)

Gomez, A.; Xolocostli, V.; Alonso, G.

2001-01-01

In all different light water nuclear reactors is very important the fuel assembly design. It has to be designed to achieve safety and efficiency performance in an economical way. The moderating ratio plays a very important role because an adequate election can provide an optimal energy production making the fuel assembly more efficient. This work analyze the moderation ratio as a function of the fuel assembly enrichment and ifs burnup, based on this study the optimal moderation ratio are obtained. Furthermore, based on numerical relations some simulation schemes are proposed to describe the behavior of the infinite multiplication factor as a function of the moderating ratio for a given fuel assembly enrichment at zero burnup. (Author)

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.

Air/fuel supply system for use in a gas turbine engine

Science.gov (United States)

Fox, Timothy A; Schilp, Reinhard; Gambacorta, Domenico

2014-06-17

A fuel injector for use in a gas turbine engine combustor assembly. The fuel injector includes a main body and a fuel supply structure. The main body has an inlet end and an outlet end and defines a longitudinal axis extending between the outlet and inlet ends. The main body comprises a plurality of air/fuel passages extending therethrough, each air/fuel passage including an inlet that receives air from a source of air and an outlet. The fuel supply structure communicates with and supplies fuel to the air/fuel passages for providing an air/fuel mixture within each air/fuel passage. The air/fuel mixtures exit the main body through respective air/fuel passage outlets.

Challenges facing air management for fuel cell systems

Energy Technology Data Exchange (ETDEWEB)

Davis, P.B. [Department of Energy (United States); Sutton, R. [Argonne National Lab. (United States); Wagner, F.W. [Energetics Incorporated (United States)

2000-07-01

The U.S. Department of Energy (DOE) and the U.S. automotive industry are working cooperatively under the auspices of the Partnership for a New Generation of Vehicles (PNGV) to develop a six-passenger automobile that can achieve up to 80 mpg. while meeting customer needs and all safety and emission requirements. These partners are continuing to invest heavily in the research and development of polymer electrolyte membrane (PEM) fuel cells as a clean and efficient energy conversion system for the PNGV. A critical challenge facing fuel cell systems for the PNGV is the development of efficient, compact, cost-effective air management systems. The U.S. Department of Energy has been exploring several compressor/expander options for pressurized fuel cell systems, including scroll, toroidal intersecting vane, turbine, twin screw, and piston technologies. Each of these technologies has strengths and weaknesses regarding efficiency, pressure ratio over turndown, size and weight, and cost. This paper will present data from the U.S. Department of Energy's research and development efforts on air management systems and will discusses recent program developments resulting from an independent peer review evaluation. (author)

Performance evaluation of an advanced air-fuel ratio controller on a stationary, rich-burn natural gas engine

Science.gov (United States)

Kochuparampil, Roshan Joseph

The advent of an era of abundant natural gas is making it an increasingly economical fuel source against incumbents such as crude oil and coal, in end-use sectors such as power generation, transportation and industrial chemical production, while also offering significant environmental benefits over these incumbents. Equipment manufacturers, in turn, are responding to widespread demand for power plants optimized for operation with natural gas. In several applications such as distributed power generation, gas transmission, and water pumping, stationary, spark-ignited, natural gas fueled internal combustion engines (ICEs) are the power plant of choice (over turbines) owing to their lower equipment and operational costs, higher thermal efficiencies across a wide load range, and the flexibility afforded to end-users when building fine-resolution horsepower topologies: modular size increments ranging from 100 kW -- 2 MW per ICE power plant compared to 2 -- 5 MW per turbine power plant. Under the U.S. Environment Protection Agency's (EPA) New Source Performance Standards (NSPS) and Reciprocating Internal Combustion Engine National Emission Standards for Hazardous Air Pollutants (RICE NESHAP) air quality regulations, these natural gas power plants are required to comply with stringent emission limits, with several states mandating even stricter emissions norms. In the case of rich-burn or stoichiometric natural gas ICEs, very high levels of sustained emissions reduction can be achieved through exhaust after-treatment that utilizes Non Selective Catalyst Reduction (NSCR) systems. The primary operational constraint with these systems is the tight air-fuel ratio (AFR) window of operation that needs to be maintained if the NSCR system is to achieve simultaneous reduction of carbon monoxide (CO), nitrogen oxides (NOx), total hydrocarbons (THC), volatile organic compounds (VOCs), and formaldehyde (CH 2O). Most commercially available AFR controllers utilizing lambda (oxygen

Model Predictive Engine Air-Ratio Control Using Online Sequential Relevance Vector Machine

Directory of Open Access Journals (Sweden)

Hang-cheong Wong

2012-01-01

Full Text Available Engine power, brake-specific fuel consumption, and emissions relate closely to air ratio (i.e., lambda among all the engine variables. An accurate and adaptive model for lambda prediction is essential to effective lambda control for long term. This paper utilizes an emerging technique, relevance vector machine (RVM, to build a reliable time-dependent lambda model which can be continually updated whenever a sample is added to, or removed from, the estimated lambda model. The paper also presents a new model predictive control (MPC algorithm for air-ratio regulation based on RVM. This study shows that the accuracy, training, and updating time of the RVM model are superior to the latest modelling methods, such as diagonal recurrent neural network (DRNN and decremental least-squares support vector machine (DLSSVM. Moreover, the control algorithm has been implemented on a real car to test. Experimental results reveal that the control performance of the proposed relevance vector machine model predictive controller (RVMMPC is also superior to DRNNMPC, support vector machine-based MPC, and conventional proportional-integral (PI controller in production cars. Therefore, the proposed RVMMPC is a promising scheme to replace conventional PI controller for engine air-ratio control.

A design study of high breeding ratio sodium cooled metal fuel core without blanket fuels

International Nuclear Information System (INIS)

Kobayashi, Noboru; Ogawa, Takashi; Ohki, Shigeo; Mizuno, Tomoyasu; Ogata, Takanari

2009-01-01

The metal fuel core is superior to the mixed oxide fuel core because of its high breeding ratio and compact core size resulting from hard neutron spectrum and high heavy metal densities. Utilizing these characteristics, a conceptual design for a high breeding ratio was performed without blanket fuels. The design conditions were set so a sodium void worth of less than 8 $, a core height of less than 150 cm, the maximum cladding temperature of 650degC, and the maximum fuel pin bundle pressure drop of 0.4 MPa. The breeding ratio of the resultant core was 1.34 with 6wt% zirconium content fuel. Applying 3wt% zirconium content fuel enhanced the breeding ratio up to 1.40. (author)

Pressurized solid oxide fuel cell integral air accumular containment

Science.gov (United States)

Gillett, James E.; Zafred, Paolo R.; Basel, Richard A.

2004-02-10

A fuel cell generator apparatus contains at least one fuel cell subassembly module in a module housing, where the housing is surrounded by a pressure vessel such that there is an air accumulator space, where the apparatus is associated with an air compressor of a turbine/generator/air compressor system, where pressurized air from the compressor passes into the space and occupies the space and then flows to the fuel cells in the subassembly module, where the air accumulation space provides an accumulator to control any unreacted fuel gas that might flow from the module.

INTERACTION OF AIR TRANSPORTATION AND FUEL-SUPPLY COMPANIES

Directory of Open Access Journals (Sweden)

I. P. Zheleznaya

2014-01-01

Full Text Available The article describes the role of aviation fuel in the life of air transport. Fueling industry worldwide solves two main tasks - ensuring the safety and economy of air traffic. In Russia, there is one more task of airlines fuel supply. The article deals with fuel pricing taking into consideration today's realities.

Advanced air staging techniques to improve fuel flexibility, reliability and emissions in fluidized bed co-combustion

Energy Technology Data Exchange (ETDEWEB)

Aamand, Lars-Erik; Leckner, Bo [Chalmers Technical Univ., Goeteborg (Sweden); Luecke, Karsten; Werther, Joachim [Technical Univ. of Hamburg-Harburg (Germany)

2001-12-01

A joint research project between the Technical University of Hamburg-Harburg and Chalmers Technical University. For operation under co-combustion the following results should be considered: The high ash content of the sewage sludge results in significantly increased ash flows. Although high alkali metal concentrations are found in the sewage sludge ash, no critical concentrations were reached and tendencies to fouling were not observed. The trace metal input rises with increased sludge fraction. However, emissions of metal compounds were well below legal limits. The trace metals tend to accumulate on the fly ash. In general, very low fuel nitrogen conversions to NO and N{sub 2}O of 2 - 4 % are achievable. With coal as a base fuel alternative air staging with secondary air supply after solids separation attains even lower NO emissions than normal staging without strongly affecting CO and SO{sub 2} emissions. Alternative staging also reduces N{sub 2}O emissions. An optimum for the excess air ratio in the riser of 1.05 was found for a total excess air ratio of 1.2. The higher the volatile content of the fuel is, the less effective the NO reduction due to air staging becomes. The measurements suggest that the optimum gas residence time regarding the emissions in CFB combustors is around 6 to 7 s. These times are achieved in commercial scale plants due to their large cyclones that perhaps partly can replace a large afterburner chamber. The circulating fluidized bed boiler can be operated in a very flexible way with various fuel mixtures up to an energy fraction of sludge of 25% without exceeding legal emission limits.

chemical determination of burnup ratio in nuclear fuels

International Nuclear Information System (INIS)

Guereli, L.

1997-01-01

Measurements of the extent of fission are important to determine the irradiation performance of a nuclear fuel. The energy released per unit mass of uranium (burnup) can be determined from measurement of the percent of heavy atoms that have fissioned during irradiation.The preferred method for this determination is choosing a suitable fission monitor (usually ''1''4''8Nd) and its determination after separation from the fuel matrix. In thermal reactor fuels where the only heavy element in the starting material is uranium, uranium depletion can be used for burnup determination. ''2''3''5U depletion method requires measurement of uranium isotopic ratios of both irradiated and unirradiated fuel. Isotopic ratios can be determined by thermal ionization mass spectrometer following separation of uranium from the fuel matrix. Separation procedures include solvent extraction, ion exchange and anion exchange chromatography. Another fission monitor used is ''1''3''9La determination by HPLC. Because La is monoisotopic (''1''3''9La) in the fuel, it can be determined by chemical analysis techniques

Modeling and optimization of the air system in polymer exchange membrane fuel cell systems

Energy Technology Data Exchange (ETDEWEB)

Bao, Cheng; Ouyang, Minggao [State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084 (China); Yi, Baolian [Dalian Institute of Chemical Physics, CAS, Dalian 116023 (China)

2006-06-01

Stack and air system are the two most important components in the fuel cell system (FCS). It is meaningful to study their properties and the trade-off between them. In this paper, a modified one-dimensional steady-state analytical fuel cell model is used. The logarithmic mean of the inlet and the outlet oxygen partial pressure is adopted to avoid underestimating the effect of air stoichiometry. And the pressure drop model in the grid-distributed flow field is included in the stack analysis. Combined with the coordinate change preprocessing and analog technique, neural network is used to treat the MAP of compressor and turbine in the air system. Three kinds of air system topologies, the pure screw compressor, serial booster and exhaust expander are analyzed in this article. A real-code genetic algorithm is programmed to obtain the global optimum air stoichiometric ratio and the cathode outlet pressure. It is shown that the serial booster and expander with the help of exhaust recycling, can improve more than 3% in the FCS efficiency comparing to the pure screw compressor. As the net power increases, the optimum cathode outlet pressure keeps rising and the air stoichiometry takes on the concave trajectory. The working zone of the proportional valve is also discussed. This presented work is helpful to the design of the air system in fuel cell system. The steady-state optimum can also be used in the dynamic control. (author)

Modeling and optimization of the air system in polymer exchange membrane fuel cell systems

Science.gov (United States)

Bao, Cheng; Ouyang, Minggao; Yi, Baolian

Stack and air system are the two most important components in the fuel cell system (FCS). It is meaningful to study their properties and the trade-off between them. In this paper, a modified one-dimensional steady-state analytical fuel cell model is used. The logarithmic mean of the inlet and the outlet oxygen partial pressure is adopted to avoid underestimating the effect of air stoichiometry. And the pressure drop model in the grid-distributed flow field is included in the stack analysis. Combined with the coordinate change preprocessing and analog technique, neural network is used to treat the MAP of compressor and turbine in the air system. Three kinds of air system topologies, the pure screw compressor, serial booster and exhaust expander are analyzed in this article. A real-code genetic algorithm is programmed to obtain the global optimum air stoichiometric ratio and the cathode outlet pressure. It is shown that the serial booster and expander with the help of exhaust recycling, can improve more than 3% in the FCS efficiency comparing to the pure screw compressor. As the net power increases, the optimum cathode outlet pressure keeps rising and the air stoichiometry takes on the concave trajectory. The working zone of the proportional valve is also discussed. This presented work is helpful to the design of the air system in fuel cell system. The steady-state optimum can also be used in the dynamic control.

Chemiluminescence-based multivariate sensing of local equivalence ratios in premixed atmospheric methane-air flames

Energy Technology Data Exchange (ETDEWEB)

Tripathi, Markandey M.; Krishnan, Sundar R.; Srinivasan, Kalyan K.; Yueh, Fang-Yu; Singh, Jagdish P.

2011-09-07

Chemiluminescence emissions from OH*, CH*, C2, and CO2 formed within the reaction zone of premixed flames depend upon the fuel-air equivalence ratio in the burning mixture. In the present paper, a new partial least square regression (PLS-R) based multivariate sensing methodology is investigated and compared with an OH*/CH* intensity ratio-based calibration model for sensing equivalence ratio in atmospheric methane-air premixed flames. Five replications of spectral data at nine different equivalence ratios ranging from 0.73 to 1.48 were used in the calibration of both models. During model development, the PLS-R model was initially validated with the calibration data set using the leave-one-out cross validation technique. Since the PLS-R model used the entire raw spectral intensities, it did not need the nonlinear background subtraction of CO2 emission that is required for typical OH*/CH* intensity ratio calibrations. An unbiased spectral data set (not used in the PLS-R model development), for 28 different equivalence ratio conditions ranging from 0.71 to 1.67, was used to predict equivalence ratios using the PLS-R and the intensity ratio calibration models. It was found that the equivalence ratios predicted with the PLS-R based multivariate calibration model matched the experimentally measured equivalence ratios within 7%; whereas, the OH*/CH* intensity ratio calibration grossly underpredicted equivalence ratios in comparison to measured equivalence ratios, especially under rich conditions ( > 1.2). The practical implications of the chemiluminescence-based multivariate equivalence ratio sensing methodology are also discussed.

Fast response air-to-fuel ratio measurements using a novel device based on a wide band lambda sensor

Science.gov (United States)

Regitz, S.; Collings, N.

2008-07-01

A crucial parameter influencing the formation of pollutant gases in internal combustion engines is the air-to-fuel ratio (AFR). During transients on gasoline and diesel engines, significant AFR excursions from target values can occur, but cycle-by-cycle AFR resolution, which is helpful in understanding the origin of deviations, is difficult to achieve with existing hardware. This is because current electrochemical devices such as universal exhaust gas oxygen (UEGO) sensors have a time constant of 50-100 ms, depending on the engine running conditions. This paper describes the development of a fast reacting device based on a wide band lambda sensor which has a maximum time constant of ~20 ms and enables cyclic AFR measurements for engine speeds of up to ~4000 rpm. The design incorporates a controlled sensor environment which results in insensitivity to sample temperature and pressure. In order to guide the development process, a computational model was developed to predict the effect of pressure and temperature on the diffusion mechanism. Investigations regarding the sensor output and response were carried out, and sensitivities to temperature and pressure are examined. Finally, engine measurements are presented.

Effects of direct injection timing and blending ratio on RCCI combustion with different low reactivity fuels

International Nuclear Information System (INIS)

Benajes, Jesús; Molina, Santiago; García, Antonio; Monsalve-Serrano, Javier

2015-01-01

Highlights: • E85 requires notable lower premixed energy ratios to achieve a stable combustion. • E10-95 leads to shorter and advanced combustion with higher maximum RoHR peaks. • E20-95, E10-98 and E10-95 reach EURO VI NOx and soot levels for all the engine loads. • E10-95 allows a significant reduction in HC and CO emissions. - Abstract: This work investigates the effects of the direct injection timing and blending ratio on RCCI performance and engine-out emissions at different engine loads using four low reactivity fuels: E10-95, E10-98, E20-95 and E85 (port fuel injected) and keeping constant the same high reactivity fuel: diesel B7 (direct injected). The experiments were conducted using a heavy-duty single-cylinder research diesel engine adapted for dual-fuel operation. All the tests were carried out at 1200 rpm. To assess the blending ratio effect, the total energy delivered to the cylinder coming from the low reactivity fuel was kept constant for the different fuel blends investigated by adjusting the low reactivity fuel mass as required in each case. In addition, a detailed analysis of the air/fuel mixing process has been developed by means of a 1-D in-house developed spray model. Results suggest that notable higher diesel amount is required to achieve a stable combustion using E85. This fact leads to higher NOx levels and unacceptable ringing intensity. By contrast, EURO VI NOx and soot levels are fulfilled with E20-95, E10-98 and E10-95. Finally, the higher reactivity of E10-95 results in a significant reduction in CO and HC emissions, mainly at low load

Forecasting Air Traffic and corresponding Jet-Fuel Demand until 2025

International Nuclear Information System (INIS)

Cheze, Benoit; Gastineau, Pascal; Chevallier, Julien

2010-01-01

This paper provides i) air traffic and ii) Jet-Fuel demand projections at the worldwide level and for eight geographical zones until 2025. The general methodology may be summarized in two steps. First, air traffic forecasts are estimated using econometric methods. The modeling is performed for eight geographical zones, by using dynamic panel-data econometrics. Once estimated from historical data, the model is then used to generate air traffic forecasts. Second, the conversion of air traffic projections into quantities of Jet-Fuel is accomplished using the 'Traffic Efficiency' method developed previously by UK DTI to support the IPCC (IPCC (1999)). One of our major contribution consists in proposing an alternative methodology to obtain Energy Efficiency coefficients and energy efficiency improvements estimates based on modeling at the macro-level. These estimates are obtained by directly comparing the evolution of both Jet-Fuel consumption and air traffic time series from 1983 to 2006. According to our 'Business As Usual' scenario, air traffic should increase by about 100% between 2008 and 2025 at the world level, corresponding to a yearly average growth rate of about 4.7%. World Jet-Fuel demand is expected to increase by about 38% during the same period, corresponding to a yearly average growth rate of about 1, 9% per year. Air traffic energy efficiency improvements yield effectively to reduce the effect of air traffic rise on the Jet-Fuel demand increase, but do not annihilate it. Thus, Jet- Fuel demand is unlikely to diminish unless there is a radical technological shift, or air travel demand is restricted. (authors)

Design Optimization of a Micro-Combustor for Lean, Premixed Fuel-Air Mixtures

Science.gov (United States)

Powell, Leigh Theresa

Present technology has been shifting towards miniaturization of devices for energy production for portable electronics. Micro-combustors, when incorporated into a micro-power generation system, provide the energy desired in the form of hot gases to power such technology. This creates the need for a design optimization of the micro-combustor in terms of geometry, fuel choice, and material selection. A total of five micro-combustor geometries, three fuels, and three materials were computationally simulated in different configurations in order to determine the optimal micro-combustor design for highest efficiency. Inlet velocity, equivalence ratio, and wall heat transfer coefficient were varied in order to test a comprehensive range of micro-combustor parameters. All simulations completed for the optimization study used ANSYS Fluent v16.1 and post-processing of the data was done in CFD Post v16.1. It was found that for lean, premixed fuel-air mixtures (φ = 0.6 - 0.9) ethane (C 2H6) provided the highest flame temperatures when ignited within the micro-combustor geometries. An aluminum oxide converging micro-combustor burning ethane and air at an equivalence ratio of 0.9, an inlet velocity of 0.5 m/s, and heat transfer coefficient of 5 W/m2-K was found to produce the highest combustor efficiency, making it the optimal choice for a micro-combustor design. It is proposed that this geometry be experimentally and computationally investigated further in order to determine if additional optimization can be achieved.

Effect of Intake Air Filter Condition on Vehicle Fuel Economy

Energy Technology Data Exchange (ETDEWEB)

Norman, Kevin M [ORNL; Huff, Shean P [ORNL; West, Brian H [ORNL

2009-02-01

The U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy and the U.S. Environmental Protection Agency (EPA) jointly maintain a fuel economy website (www.fueleconomy.gov), which helps fulfill their responsibility under the Energy Policy Act of 1992 to provide accurate fuel economy information [in miles per gallon (mpg)] to consumers. The site provides information on EPA fuel economy ratings for passenger cars and light trucks from 1985 to the present and other relevant information related to energy use such as alternative fuels and driving and vehicle maintenance tips. In recent years, fluctuations in the price of crude oil and corresponding fluctuations in the price of gasoline and diesel fuels have renewed interest in vehicle fuel economy in the United States. (User sessions on the fuel economy website exceeded 20 million in 2008 compared to less than 5 million in 2004 and less than 1 million in 2001.) As a result of this renewed interest and the age of some of the references cited in the tips section of the website, DOE authorized the Oak Ridge National Laboratory (ORNL) Fuels, Engines, and Emissions Research Center (FEERC) to initiate studies to validate and improve these tips. This report documents a study aimed specifically at the effect of engine air filter condition on fuel economy. The goal of this study was to explore the effects of a clogged air filter on the fuel economy of vehicles operating over prescribed test cycles. Three newer vehicles (a 2007 Buick Lucerne, a 2006 Dodge Charger, and a 2003 Toyota Camry) and an older carbureted vehicle were tested. Results show that clogging the air filter has no significant effect on the fuel economy of the newer vehicles (all fuel injected with closed-loop control and one equipped with MDS). The engine control systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel consumption was not increased. The carbureted engine did show a decrease in

Performance of PEM Liquid-Feed Direct Methanol-Air Fuel Cells

Science.gov (United States)

Narayanan, S. R.

1995-01-01

A direct methanol-air fuel cell operating at near atmospheric pressure, low-flow rate air, and at temperatures close to 60oC would tremendously enlarge the scope of potential applications. While earlier studies have reported performance with oxygen, the present study focuses on characterizing the performance of a PEM liquid feed direct methanol-air cell consisting of components developed in house. These cells employ Pt-Ru catalyst in the anode, Pt at the cathode and Nafion 117 as the PEM. The effect of pressure, flow rate of air and temperature on cell performance has been studied. With air, the performance level is as high as 0.437 V at 300 mA/cm2 (90oC, 20 psig, and excess air flow) has been attained. Even more significant is the performance level at 60oC, 1 atm and low flow rates of air (3-5 times stoichiometric), which is 0.4 V at 150 mA/cm2. Individual electrode potentials for the methanol and air electrode have been separated and analyzed. Fuel crossover rates and the impact of fuel crossover on the performance of the air electrode have also been measured. The study identifies issues specific to the methanol-air fuel cell and provides a basis for improvement strategies.

Interim results from UO2 fuel oxidation tests in air

International Nuclear Information System (INIS)

Campbell, T.K.; Gilbert, E.R.; Thornhill, C.K.; White, G.D.; Piepel, G.F.; Griffin, C.W.j.

1987-08-01

An experimental program is being conducted at Pacific Northwest Laboratory (PNL) to extend the characterization of spent fuel oxidation in air. To characterize oxidation behavior of irradiated UO 2 , fuel oxidation tests were performed on declad light-water reactor spent fuel and nonirradited UO 2 pellets in the temperature range of 135 to 250 0 C. These tests were designed to determine the important independent variables that might affect spent fuel oxidation behavior. The data from this program, when combined with the test results from other programs, will be used to develop recommended spent fuel dry-storage temperature limits in air. This report describes interim test results. The initial PNL investigations of nonirradiated and spent fuels identified the important testing variables as temperature, fuel burnup, radiolysis of the air, fuel microstructure, and moisture in the air. Based on these initial results, a more extensive statistically designed test matrix was developed to study the effects of temperature, burnup, and moisture on the oxidation behavior of spent fuel. Oxidation tests were initiated using both boiling-water reactor and pressurized-water reactor fuels from several different reactors with burnups from 8 to 34 GWd/MTU. A 10 5 R/h gamma field was applied to the test ovens to simulate dry storage cask conditions. Nonirradiated fuel was included as a control. This report describes experimental results from the initial tests on both the spent and nonirradiated fuels and results to date on the tests in a 10 5 R/h gamma field. 33 refs., 51 figs., 6 tabs

The influence of droplet evaporation on fuel-air mixing rate in a burner

Science.gov (United States)

Komiyama, K.; Flagan, R. C.; Heywood, J. B.

1977-01-01

Experiments involving combustion of a variety of hydrocarbon fuels in a simple atmospheric pressure burner were used to evaluate the role of droplet evaporation in the fuel/air mixing process in liquid fuel spray flames. Both air-assist atomization and pressure atomization processes were studied; fuel/air mixing rates were determined on the basis of cross-section average oxygen concentrations for stoichiometric overall operation. In general, it is concluded that droplets act as point sources of fuel vapor until evaporation, when the fuel jet length scale may become important in determining nonuniformities of the fuel vapor concentration. In addition, air-assist atomizers are found to have short droplet evaporation times with respect to the duration of the fuel/air mixing process, while for the pressure jet atomizer the characteristic evaporation and mixing times are similar.

Effect of aviation fuel type and fuel injection conditions on the spray characteristics of pressure swirl and hybrid air blast fuel injectors

Science.gov (United States)

Feddema, Rick

Feddema, Rick T. M.S.M.E., Purdue University, December 2013. Effect of Aviation Fuel Type and Fuel Injection Conditions on the Spray Characteristics of Pressure Swirl and Hybrid Air Blast Fuel Injectors. Major Professor: Dr. Paul E. Sojka, School of Mechanical Engineering Spray performance of pressure swirl and hybrid air blast fuel injectors are central to combustion stability, combustor heat management, and pollutant formation in aviation gas turbine engines. Next generation aviation gas turbine engines will optimize spray atomization characteristics of the fuel injector in order to achieve engine efficiency and emissions requirements. Fuel injector spray atomization performance is affected by the type of fuel injector, fuel liquid properties, fuel injection pressure, fuel injection temperature, and ambient pressure. Performance of pressure swirl atomizer and hybrid air blast nozzle type fuel injectors are compared in this study. Aviation jet fuels, JP-8, Jet A, JP-5, and JP-10 and their effect on fuel injector performance is investigated. Fuel injector set conditions involving fuel injector pressure, fuel temperature and ambient pressure are varied in order to compare each fuel type. One objective of this thesis is to contribute spray patternation measurements to the body of existing drop size data in the literature. Fuel droplet size tends to increase with decreasing fuel injection pressure, decreasing fuel injection temperature and increasing ambient injection pressure. The differences between fuel types at particular set conditions occur due to differences in liquid properties between fuels. Liquid viscosity and surface tension are identified to be fuel-specific properties that affect the drop size of the fuel. An open aspect of current research that this paper addresses is how much the type of aviation jet fuel affects spray atomization characteristics. Conventional aviation fuel specifications are becoming more important with new interest in alternative

Air quality effects of alternative fuels. Final report

Energy Technology Data Exchange (ETDEWEB)

Guthrie, P.; Ligocki, M.; Looker, R.; Cohen, J.

1997-11-01

To support the Alternative Fuels Utilization Program, a comparison of potential air quality effects of alternative transportation fuels is being performed. This report presents the results of Phase 1 of this program, focusing on reformulated gasoline (RFG), methanol blended with 15 percent gasoline (M85), and compressed natural gas (CNG). The fuels are compared in terms of effects on simulated future concentrations of ozone and mobile source air toxics in a photochemical grid model. The fuel comparisons were carried out for the future year 2020 and assumed complete replacement of gasoline in the projected light-duty gasoline fleet by each of the candidate fuels. The model simulations were carried out for the areas surrounding Los Angeles and Baltimore/DC, and other (non-mobile) sources of atmospheric emissions were projected according to published estimates of economic and population growth, and planned emission control measures specific to each modeling domain. The future-year results are compared to a future-year run with all gasoline vehicle emissions removed. The results of the comparison indicate that the use of M85 is likely to produce similar ozone and air toxics levels as those projected from the use of RFG. Substitution of CNG is projected to produce significantly lower levels of ozone and the mobile source air toxics than those projected for RFG or M85. The relative benefits of CNG substitution are consistent in both modeling domains. The projection methodologies used for the comparison are subject to a large uncertainty, and modeled concentration distributions depend on meteorological conditions. The quantitative comparison of fuel effects is thus likely to be sensitive to alternative assumptions. The consistency of the results for two very different modeling domains, using very different base assumptions, lends credibility to the qualitative differentiation among these fuels. 32 refs., 42 figs., 47 tabs.

Study of fuel control strategy based on an fuel behavior model for starting conditions; Nenryo kyodo model ni motozuita shidoji no nenryo hosei hosho ni tsuite no kosatsu

Energy Technology Data Exchange (ETDEWEB)

Nakajima, Y; Uchida, M; Iwano, H; Oba, H [Nissan Motor Co. Ltd., Tokyo (Japan)

1997-10-01

We have applied a fuel behavior model to a fuel injection system which we call SOFIS (Sophisticated and Optimized Fuel Injection System) so that we get air/fuel ratio control accuracy and good driveability. However the fuel behavior under starting conditions is still not clear. To meet low emission rules and to get better driveability under starting conditions, better air/fuel ratio control is necessary. Now we have understood the ignition timing, injection timing, and injection pulse width required in such conditions. In former days, we analyzed the state of the air/fuel mixture under cold conditions and made a new fuel behavior model which considered fuel loss such as hydrocarbons and dissolution into oil and so on. Al this time, we have applied this idea to starting. We confirm this new model offers improved air/fuel ratio control. 6 refs., 9 figs., 3 tabs.

Porous fuel air mixing enhancing nozzle (PFAMEN)

NARCIS (Netherlands)

Reijnders, J.J.E.; Boot, M.D.; Luijten, C.C.M.; Frijters, P.J.M.; Goey, de L.P.H.

2009-01-01

One of the challenges with conventional diesel engines is the emission of soot. To reduce soot emission whilst maintaining fuel efficiency, an important pathway is to improve the fuel-air mixing process. This can be achieved by creating small droplets in order to enhance evaporation. Furthermore,

Storage of LWR spent fuel in air. Volume 3, Results from exposure of spent fuel to fluorine-contaminated air

Energy Technology Data Exchange (ETDEWEB)

Cunningham, M.E.; Thomas, L.E.

1995-06-01

The Behavior of Spent Fuel in Storage (BSFS) Project has conducted research to develop data on spent nuclear fuel (irradiated U0{sub 2}) that could be used to support design, licensing, and operation of dry storage installations. Test Series B conducted by the BSFS Project was designed as a long-term study of the oxidation of spent fuel exposed to air. It was discovered after the exposures were completed in September 1990 that the test specimens had been exposed to an atmosphere of bottled air contaminated with an unknown quantity of fluorine. This exposure resulted in the test specimens reacting with both the oxygen and the fluorine in the oven atmospheres. The apparent source of the fluorine was gamma radiation-induced chemical decomposition of the fluoro-elastomer gaskets used to seal the oven doors. This chemical decomposition apparently released hydrofluoric acid (HF) vapor into the oven atmospheres. Because the Test Series B specimens were exposed to a fluorine-contaminated oven atmosphere and reacted with the fluorine, it is recommended that the Test Series B data not be used to develop time-temperature limits for exposure of spent nuclear fuel to air. This report has been prepared to document Test Series B and present the collected data and observations.

Storage of LWR spent fuel in air. Volume 3, Results from exposure of spent fuel to fluorine-contaminated air

International Nuclear Information System (INIS)

Cunningham, M.E.; Thomas, L.E.

1995-06-01

The Behavior of Spent Fuel in Storage (BSFS) Project has conducted research to develop data on spent nuclear fuel (irradiated U0 2 ) that could be used to support design, licensing, and operation of dry storage installations. Test Series B conducted by the BSFS Project was designed as a long-term study of the oxidation of spent fuel exposed to air. It was discovered after the exposures were completed in September 1990 that the test specimens had been exposed to an atmosphere of bottled air contaminated with an unknown quantity of fluorine. This exposure resulted in the test specimens reacting with both the oxygen and the fluorine in the oven atmospheres. The apparent source of the fluorine was gamma radiation-induced chemical decomposition of the fluoro-elastomer gaskets used to seal the oven doors. This chemical decomposition apparently released hydrofluoric acid (HF) vapor into the oven atmospheres. Because the Test Series B specimens were exposed to a fluorine-contaminated oven atmosphere and reacted with the fluorine, it is recommended that the Test Series B data not be used to develop time-temperature limits for exposure of spent nuclear fuel to air. This report has been prepared to document Test Series B and present the collected data and observations

Performance analysis of air-standard Diesel cycle using an alternative irreversible heat transfer approach

International Nuclear Information System (INIS)

Al-Hinti, I.; Akash, B.; Abu-Nada, E.; Al-Sarkhi, A.

2008-01-01

This study presents the investigation of air-standard Diesel cycle under irreversible heat transfer conditions. The effects of various engine parameters are presented. An alternative approach is used to evaluate net power output and cycle thermal efficiency from more realistic parameters such as air-fuel ratio, fuel mass flow rate, intake temperature, engine design parameters, etc. It is shown that for a given fuel flow rate, thermal efficiency and maximum power output increase with decreasing air-fuel ratio. Also, for a given air-fuel ratio, the maximum power output increases with increasing fuel rate. However, the effect of the thermal efficiency is limited

Flame holding tolerant fuel and air premixer for a gas turbine combustor

Science.gov (United States)

York, William David; Johnson, Thomas Edward; Ziminsky, Willy Steve

2012-11-20

A fuel nozzle with active cooling is provided. It includes an outer peripheral wall, a nozzle center body concentrically disposed within the outer wall in a fuel and air pre-mixture. The fuel and air pre-mixture includes an air inlet, a fuel inlet and a premixing passage defined between the outer wall in the center body. A gas fuel flow passage is provided. A first cooling passage is included within the center body in a second cooling passage is defined between the center body and the outer wall.

An innovative system for supplying air and fuel mixture to a combustion chamber of an engine

Science.gov (United States)

Saikumar, G. R. Bharath

2018-04-01

Conventional carburetors are being used since decades to ensure that the desired ratio of air and fuel enters the combustion chamber for combustion for the purpose of generating power in an Spark Ignition(SI) internal combustion engine. However to increase the efficiency, the carburetor system is gradually being replaced by fuel injection systems. Fuel injection systems use injectors to supply pressurized fuel into the combustion chamber. Owing to the high initial and maintenance cost, carburetors are still ruling in the low cost vehicle domain. An innovative concept is conceived, which is an alternative method to the carburetor system to supply the air and fuel mixture to a combustion chamber of an engine. This system comprises of an inner hollow cylinder with minute holes drilled along its length with an outer cylinder capable of sliding along its length or its longitudinal axis. This system is placed in the venturi instead of the conventional carburetor system. Fuel enters from the bottom inlet of the inner cylinder and flows out through the holes provided along its length. The fuel flow from the inner cylinder is dependent on the size and the number of holes exposed at that instance by the sliding outer cylinder which in turn is connected to the throttle or accelerator.

The prospect for fuel ion ratio measurements in ITER by collective Thomson scattering

DEFF Research Database (Denmark)

Stejner Pedersen, Morten; Korsholm, Søren Bang; Nielsen, Stefan Kragh

2012-01-01

We show that collective Thomson scattering (CTS) holds the potential to become a new diagnostic principle for measurements of the fuel ion ratio, nT/nD, in ITER. Fuel ion ratio measurements will be important for plasma control and machine protection in ITER. Measurements of ion cyclotron structures...... in CTS spectra have been suggested as the basis for a new fuel ion ratio diagnostic which would be well suited for reactor environments and capable of providing spatially resolved measurements in the plasma core. Such measurements were demonstrated in recent experiments in the TEXTOR tokamak. Here we...... conduct a sensitivity study to investigate the potential measurement accuracy of a CTS fuel ion ratio diagnostic on ITER. The study identifies regions of parameter space in which CTS can be expected to provide useful information on plasma composition, and we find that a CTS fuel ion ratio diagnostic could...

Thermodynamic and transport properties of air and its products of combustion with ASTMA-A-1 fuel and natural gas at 20, 30, and 40 atmospheres

Science.gov (United States)

Poferl, D. J.; Svehla, R. A.

1973-01-01

The isentropic exponent, molecular weight, viscosity, specific heat at constant pressure, thermal conductivity, Prandtl number, and enthalpy were calculated for air, the combustion products of ASTM-A-1 jet fuel and air, and the combustion products of natural gas and air. The properties were calculated over a temperature range from 300 to 2800 K in 100 K increments and for pressures of 20, 30 and 40 atmospheres. The data for natural gas and ASTM-A-1 were calculated for fuel-air ratios from zero to stoichiometric in 0.01 increments.

Liquid air fueled open–closed cycle Stirling engine

International Nuclear Information System (INIS)

Xu, Weiqing; Wang, Jia; Cai, Maolin; Shi, Yan

2015-01-01

Highlights: • Energy of liquid air is divided into cryogenic energy and expansion energy. • Open–closed cycle Stirling mechanism is employed to improve efficiency. • The Schmidt theory is modified to describe temperature variation in cold space. - Abstract: An unconventional Stirling engine is proposed and its theoretical analysis is performed. The engine belongs to a “cryogenic heat engine” that is fueled by cryogenic medium. Conventional “cryogenic heat engine” employs liquid air as pressure source, but disregards its heat-absorbing ability. Therefore, its efficiency can only be improved by increasing vapor pressure, accordingly increasing the demand on pressure resistance and sealing. In the proposed engine, the added Stirling mechanism helps achieve its high efficiency and simplicity by utilizing the heat-absorbing ability of liquid air. On one hand, based on Stirling mechanism, gas in the hot space absorbs heat from atmosphere when expanding; gas in the cold space is cooled down by liquid air when compressed. Taking atmosphere as heat source and liquid air as heat sink, a closed Stirling cycle is formed. On the other hand, an exhaust port is set in the hot space. When expanding in the hot space, the vaporized gas is discharged through the exhaust port. Thus, an open cycle is established. To model and analyze the system, the Schmidt theory is modified to describe temperature variation in the cold space, and irreversible characteristic of regenerator is incorporated in the thermodynamic model. The results obtained from the model show that under the same working pressure, the efficiency of the proposed engine is potentially higher than that of conventional ones and to achieve the same efficiency, the working pressure could be lower with the new mechanism. Its efficiency could be improved by reducing temperature difference between the regenerator and the cold/hot space, increasing the swept volume ratio, decreasing the liquid–gas ratio. To keep

Storage of LWR spent fuel in air: Volume 1: Design and operation of a spent fuel oxidation test facility

International Nuclear Information System (INIS)

Thornhill, C.K.; Campbell, T.K.; Thornhill, R.E.

1988-12-01

This report describes the design and operation and technical accomplishments of a spent-fuel oxidation test facility at the Pacific Northwest Laboratory. The objective of the experiments conducted in this facility was to develop a data base for determining spent-fuel dry storage temperature limits by characterizing the oxidation behavior of light-water reactor (LWR) spent fuels in air. These data are needed to support licensing of dry storage in air as an alternative to spent-fuel storage in water pools. They are to be used to develop and validate predictive models of spent-fuel behavior during dry air storage in an Independent Spent Fuel Storage Installation (ISFSI). The present licensed alternative to pool storage of spent fuel is dry storage in an inert gas environment, which is called inerted dry storage (IDS). Licensed air storage, however, would not require monitoring for maintenance of an inert-gas environment (which IDS requires) but does require the development of allowable temperature limits below which UO 2 oxidation in breached fuel rods would not become a problem. Scoping tests at PNL with nonirradiated UO 2 pellets and spent-fuel fragment specimens identified the need for a statistically designed test matrix with test temperatures bounding anticipated maximum acceptable air-storage temperatures. This facility was designed and operated to satisfy that need. 7 refs

Tip-to-tail numerical simulation of a hypersonic air-breathing engine with ethylene fuel

Science.gov (United States)

Dharavath, Malsur; Manna, P.; Chakraborty, Debasis

2016-11-01

End to end CFD simulations of external and internal flow paths of an ethylene fueled hypersonic airbreathing vehicle with including forebody, horizontal fins, vertical fins, intake, combustor, single expansion ramp nozzle are carried out. The performance of the scramjet combustor and vehicle net thrust-drag is calculated for hypersonic cruise condition. Three-dimensional Navier-Stokes equations are solved along with SST-k-ω turbulence model using the commercial CFD software CFX-14. Single step chemical reaction based on fast chemistry assumption is used for combustion of gaseous ethylene fuel. Simulations captured complex shock structures including the shocks generated from the vehicle nose and compression ramps, impingement of cowl-shock on vehicle undersurface and its reflection in the intake and combustor etc. Various thermochemical parameters are analyzed and performance parameters are evaluated for nonreacting and reacting cases. Very good mixing ( 98%) of fuel with incoming air stream is observed. Positive thrust-drag margins are obtained for fuel equivalence ratio of 0.6 and computed combustion efficiency is observed to be 94 %. Effect of equivalence ratio on the vehicle performance is studied parametrically. Though the combustion efficiency has come down by 8% for fuel equivalence ratio of 0.8, net vehicle thrust is increased by 44%. Heat flux distribution on the various walls of the whole vehicle including combustor is estimated for the isothermal wall condition of 1000 K in reacting flow. Higher local heat flux values are observed at all the leading edges of the vehicle (i.e., nose, wing, fin and cowl leading edges) and strut regions of the combustor.

Spent fuel treatment to allow storage in air

International Nuclear Information System (INIS)

Williams, K.L.

1988-01-01

During Fiscal Year 1987 (FY-87), research began at the Idaho National Engineering Laboratory (INEL) to develop a treatment material and process to coat fuel rods in commercial spent fuel assemblies to allow the assemblies to be stored in hot (up to 380 0 C) air without oxidation of the fuel. This research was conducted under a research and development fund provided by the U.S. Department of Energy (DOE) and independently administered by EG and G Idaho, Inc., DOE's prime contractor at the INEL. The objectives of the research were to identify and evaluate possible treatment processes and materials, identify areas of uncertainty, and to recommend the most likely candidate to allow spent fuel dry storage in hot air. The results of the research are described: results were promising and several good candidates were identified, but further research is needed to examine the candidates to the point where comparison is possible

Study on Combustion Oscillation of Premixed Flame with Pilot Fuel at Elevated Pressures

Science.gov (United States)

Ohtsuka, Masaya; Yoshida, Shohei; Hirata, Yoshitaka; Kobayashi, Nariyoshi

Acoustically-coupled combustion oscillation is studied for premixed flame with pilot fuel to be used in gas turbine combustors. Premixed gas is passed through swirl vanes and burnt with the centrally injected pilot fuel. The dependencies of pressure, fuel to air ratio, premixed fuel rate, inlet velocity and air temperature on the combustion oscillation are investigated. Two kinds of oscillation modes of ˜100Hz and ˜350Hz are activated according to inlet velocities. Fluctuating pressures are amplified when the premixed fuel rate is over ˜80% at elevated pressures. The fluctuating pressure peak moves to a higher premixed fuel ratio region with increased pressure or fuel to air ratio for the Helmholz type mode. Combustion oscillation occurs when the pilot fuel velocity is changed proportionally with the flame length.

Toxic and hazardous air pollutants from co-firing biomass fuels, fossil fuels, MSW and RDF

International Nuclear Information System (INIS)

Junge, D.C.

1991-01-01

Toxic and hazardous pollutants are defined and then are considered from the perspective of pollutants which enter the combustion process with the fuel (principally the metals and metallic compounds) and pollutants which are formed as products of incomplete combustion. Control strategies are reviewed through the entire process including fuel preparation and storage, combustion control and the application of air pollution control devices. Measurement techniques for specific toxic and hazardous air pollutants are discussed

Diffusion air effects on the soot axial distribution concentration in a premixed acetylene/air flame

Energy Technology Data Exchange (ETDEWEB)

Fassani, Fabio Luis; Santos, Alex Alisson Bandeira; Goldstein Junior, Leonardo [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia Termica e de Fluidos]. E-mails: fassani@fem.unicamp.br; absantos@fem.unicamp.br; leonardo@fem.unicamp.br; Ferrari, Carlos Alberto [Universidade Estadual de Campinas, SP (Brazil). Inst. de Fisica. Dept. de Eletronica Quantica]. E-mail: ferrari@ifi.unicamp.br

2000-07-01

Soot particles are produced during the high temperature pyrolysis or combustion of hydrocarbons. The emission of soot from a combustor, or from a flame, is determined by the competition between soot formation and its oxidation. Several factors affect these processes, including the type of fuel, the air-to-fuel ratio, flame temperature, pressure, and flow pattern. In this paper, the influence of the induced air diffusion on the soot axial distribution concentration in a premixed acetylene/air flame was studied. The flame was generated in a vertical axis burner in which the fuel - oxidant mixture flow was surrounded by a nitrogen discharge coming from the annular region between the burner tube and an external concentric tube. The nitrogen flow provided a shield that protected the flame from the diffusion of external air, enabling its control. The burner was mounted on a step-motor driven, vertical translation table. The use of several air-to-fuel ratios made possible to establish the sooting characteristics of this flame, by measuring soot concentration along the flame height with a non-intrusive laser light absorption technique. (author)

Effect analysis of air introduced by pressurization on fuel rod performances

International Nuclear Information System (INIS)

Ren Qisen; Liu Tong; Sheng Guofu

2012-01-01

In the process of pressurization and seal welding, it is common practice to vacuumize before gas filling for the sake of preventing introducing air and other impurities, which would affect the gas composition inside of the fuel rod. However, vacuumization during pressurization is likely not being required sometimes in order to simplify the fabrication procedure. In the present work, based on the AFA3G fuel rod design with 2 MPa of filling gas, analyses on fuel rod performances were carried out under the condition of pressurization with and without vacuumization, respectively. Furthermore, the effect on hydrogen content in fuel rod was preliminarily discussed. Results indicate that the impacts of air composition introduced by pressurization on fuel rod thermal-mechanical performances, such as internal pressure and fuel center temperature, were extremely slight. The gap conductance varies to some extent as a result of the change of gas composition due to air introduced in fuel rod. The impact of humidity on water content in fuel rod is negligible at a low temperature of around 25℃. However, at higher temperature, it is essential to pay attention on the control of fabrication process, and prevent much moisture entering into the fuel rod and increasing the probability of hydriding failure. (authors)

An efficient mathematical model for air-breathing PEM fuel cells

International Nuclear Information System (INIS)

Ismail, M.S.; Ingham, D.B.; Hughes, K.J.; Ma, L.; Pourkashanian, M.

2014-01-01

Graphical abstract: The effects of the ambient humidity on the performance of air-breathing PEM fuel cells become more pronounced as the ambient temperature increases. The polarisation curves have been generated using the in-house developed MATLAB® application, Polarisation Curve Generator, which is available in the supplementary data. - Highlights: • An efficient mathematical model has been developed for an air-breathing PEM fuel cell. • The fuel cell performance is significantly over-predicted if the Joule and entropic heats are neglected. • The fuel cell performance is highly sensitive to the state of water at the thermodynamic equilibrium. • The cell potential dictates the favourable ambient conditions for the fuel cell. - Abstract: A simple and efficient mathematical model for air-breathing proton exchange membrane (PEM) fuel cells has been built. One of the major objectives of this study is to investigate the effects of the Joule and entropic heat sources, which are often neglected, on the performance of air-breathing PEM fuel cells. It is found that the fuel cell performance is significantly over-predicted if one or both of these heat sources is not incorporated into the model. Also, it is found that the performance of the fuel cell is highly sensitive to the state of the water at the thermodynamic equilibrium magnitude as both the entropic heat and the Nernst potential considerably increase if water is assumed to be produced in liquid form rather than in vapour form. Further, the heat of condensation is shown to be small and therefore, under single-phase modelling, has a negligible effect on the performance of the fuel cell. Finally, the favourable ambient conditions depend on the operating cell potential. At intermediate cell potentials, a mild ambient temperature and low humidity are favoured to maintain high membrane conductivity and mitigate water flooding. At low cell potentials, low ambient temperature and high humidity are favoured to

Air Quality and Acute Respiratory Illness in Biomass Fuel using homes in Bagamoyo, Tanzania

Directory of Open Access Journals (Sweden)

Satoshi Nakai

2007-03-01

Full Text Available Respiratory Diseases are public health concern worldwide. The diseases have been associated with air pollution especially indoor air pollution from biomass fuel burning in developing countries. However, researches on pollution levels and on association of respiratory diseases with biomass fuel pollution are limited. A study was therefore undertaken to characterize the levels of pollutants in biomass fuel using homes and examine the association between biomass fuel smoke exposure and Acute Respiratory Infection (ARI disease in Nianjema village in Bagamoyo, Tanzania. Pollution was assessed by measuring PM10, NO2, and CO concentrations in kitchen, living room and outdoors. ARI prevalence was assessed by use of questionnaire which gathered health information for all family members under the study. Results showed that PM10, NO2, and CO concentrations were highest in the kitchen and lowest outdoors. Kitchen concentrations were highest in the kitchen located in the living room for all pollutants except CO. Family size didn’t have effect on the levels measured in kitchens. Overall ARI prevalence for cooks and children under age 5 making up the exposed group was 54.67% with odds ratio (OR of 5.5; 95% CI 3.6 to 8.5 when compared with unexposed men and non-regular women cooks. Results of this study suggest an association between respiratory diseases and exposure to domestic biomass fuel smoke, but further studies with improved design are needed to confirm the association.

Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

DEFF Research Database (Denmark)

Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Bindslev, Henrik

2011-01-01

ratio. Measurements of the fuel ion ratio will be important for plasma control and machine protection in future experiments with burning fusion plasmas. Here we examine the theoretical basis for fuel ion ratio measurements by CTS. We show that the sensitivity to plasma composition is enhanced......For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio—i.e. the tritium to deuterium density...... by the signatures of ion cyclotron motion and ion Bernstein waves which appear for scattering geometries with resolved wave vectors near perpendicular to the magnetic field. We investigate the origin and properties of these features in CTS spectra and give estimates of their relative importance for fuel ion ratio...

Performance and emissions of a supercharged dual-fuel engine fueled by hydrogen-rich coke oven gas

Energy Technology Data Exchange (ETDEWEB)

Roy, M.M.; Tomita, E.; Kawahara, N.; Harada, Y.; Sakane, A. [Okayama University, Okayama (Japan). Dept. of Mechanical Engineering

2009-12-15

This study investigated the engine performance and emissions of a supercharged dual-fuel engine fueled by hydrogen-rich coke oven gas and ignited by a pilot amount of diesel fuel. The engine was tested for use as a cogeneration engine, so power output while maintaining a reasonable thermal efficiency was important. Experiments were carried out at a constant pilot injection pressure and pilot quantity for different fuel-air equivalence ratios and at various injection timings without and with exhaust gas recirculation (EGR). The experimental strategy was to optimize the injection timing to maximize engine power at different fuel-air equivalence ratios without knocking and within the limit of the maximum cylinder pressure. The engine was tested first without EGR condition up to the maximum possible fuel-air equivalence ratio of 0.65. A maximum indicated mean effective pressure (IMEP) of 1425 kPa and a thermal efficiency of 39% were obtained. However, the nitrogen oxides (NOx) emissions were high. A simulated EGR up to 50% was then performed to obtain lower NOx emissions. The maximum reduction of NOx was 60% or more maintaining the similar levels of IMEP and thermal efficiency. Two-stage combustion was obtained; this is an indicator of maximum power output conditions and a precursor of knocking combustion.

Monte Carlo simulation of the effect of miniphantom on in-air output ratio

International Nuclear Information System (INIS)

Li Jun; Zhu, Timothy C.

2010-01-01

Purpose: The aim of the study was to quantify the effect of miniphantoms on in-air output ratio measurements, i.e., to determine correction factors for in-air output ratio. Methods: Monte Carlo (MC) simulations were performed to simulate in-air output ratio measurements by using miniphantoms made of various materials (PMMA, graphite, copper, brass, and lead) and with different longitudinal thicknesses or depths (2-30 g/cm 2 ) in photon beams of 6 and 15 MV, respectively, and with collimator settings ranging from 3x3 to 40x40 cm 2 . EGSnrc and BEAMnrc (2007) software packages were used. Photon energy spectra corresponding to the collimator settings were obtained from BEAMnrc code simulations on a linear accelerator and were used to quantify the components of in-air output ratio correction factors, i.e., attenuation, mass energy absorption, and phantom scatter correction factors. In-air output ratio correction factors as functions of miniphantom material, miniphantom longitudinal thickness, and collimator setting were calculated and compared to a previous experimental study. Results: The in-air output ratio correction factors increase with collimator opening and miniphantom longitudinal thickness for all the materials and for both energies. At small longitudinal thicknesses, the in-air output ratio correction factors for PMMA and graphite are close to 1. The maximum magnitudes of the in-air output ratio correction factors occur at the largest collimator setting (40x40 cm 2 ) and the largest miniphantom longitudinal thickness (30 g/cm 2 ): 1.008±0.001 for 6 MV and 1.012±0.001 for 15 MV, respectively. The MC simulations of the in-air output ratio correction factor confirm the previous experimental study. Conclusions: The study has verified that a correction factor for in-air output ratio can be obtained as a product of attenuation correction factor, mass energy absorption correction factor, and phantom scatter correction factor. The correction factors obtained in the

Fault Tolerance Automotive Air-Ratio Control Using Extreme Learning Machine Model Predictive Controller

OpenAIRE

Pak Kin Wong; Hang Cheong Wong; Chi Man Vong; Tong Meng Iong; Ka In Wong; Xianghui Gao

2015-01-01

Effective air-ratio control is desirable to maintain the best engine performance. However, traditional air-ratio control assumes the lambda sensor located at the tail pipe works properly and relies strongly on the air-ratio feedback signal measured by the lambda sensor. When the sensor is warming up during cold start or under failure, the traditional air-ratio control no longer works. To address this issue, this paper utilizes an advanced modelling technique, kernel extreme learning machine (...

Adaptive Control Using Fully Online Sequential-Extreme Learning Machine and a Case Study on Engine Air-Fuel Ratio Regulation

Directory of Open Access Journals (Sweden)

Pak Kin Wong

2014-01-01

Full Text Available Most adaptive neural control schemes are based on stochastic gradient-descent backpropagation (SGBP, which suffers from local minima problem. Although the recently proposed regularized online sequential-extreme learning machine (ReOS-ELM can overcome this issue, it requires a batch of representative initial training data to construct a base model before online learning. The initial data is usually difficult to collect in adaptive control applications. Therefore, this paper proposes an improved version of ReOS-ELM, entitled fully online sequential-extreme learning machine (FOS-ELM. While retaining the advantages of ReOS-ELM, FOS-ELM discards the initial training phase, and hence becomes suitable for adaptive control applications. To demonstrate its effectiveness, FOS-ELM was applied to the adaptive control of engine air-fuel ratio based on a simulated engine model. Besides, controller parameters were also analyzed, in which it is found that large hidden node number with small regularization parameter leads to the best performance. A comparison among FOS-ELM and SGBP was also conducted. The result indicates that FOS-ELM achieves better tracking and convergence performance than SGBP, since FOS-ELM tends to learn the unknown engine model globally whereas SGBP tends to “forget” what it has learnt. This implies that FOS-ELM is more preferable for adaptive control applications.

Prediction of air-fuel and oxy-fuel combustion through a generic gas radiation property model

International Nuclear Information System (INIS)

Yin, Chungen

2017-01-01

Highlights: • A gas radiation model for general combustion CFD presented, programmed & verified. • Its general applicability/practical accuracy demonstrated in air-fuel and oxy-fuel. • Useful guidelines for air-fuel and oxy-fuel combustion CFD suggested. • Important to include the impact of CO in gas radiation for oxy-fuel combustion CFD. - Abstract: Thermal radiation plays an important role in heat transfer in combustion furnaces. The weighted-sum-of-gray-gases model (WSGGM), representing a good compromise between computational efficiency and accuracy, is commonly used in computational fluid dynamics (CFD) modeling of combustion processes for evaluating gaseous radiative properties. However, the WSGGMs still have some limitations in practical use, e.g., unable to naturally accommodate different combustion environments, difficult to accurately address the variations in species concentrations in a flame, and inconvenient to account for the impacts of participating species other than H_2O and CO_2. As a result, WSGGMs with different coefficients have been published for specific applications. In this paper, a reliable generic model for gaseous radiation property calculation, which is a computationally efficient exponential wide band model (E-EWBM) applicable to combustion CFD and able to naturally solve all the practical limitations of the WSGGMs, is presented, programmed and verified. The model is then implemented to CFD simulation of a 300 kW air-fuel and a 0.8 MW oxy-fuel combustion furnace, respectively, to demonstrate its computational applicability to general combustion CFD and its capability in producing reliable CFD results for different combustion environments. It is found that the usefulness of the WSGGMs in oxy-fuel combustion CFD is compromised if the important impacts of high levels of CO under oxy-fuel combustion cannot be accounted for. The E-EWBM that appropriately takes the impacts of H_2O, CO_2, CO and CH_4 into account is a good replacement

Effects of alternative-fuel vehicles on air quality in Ontario, Canada

International Nuclear Information System (INIS)

Kantor, I.; Fowler, M.; Hajimiragha, A.; Canizares, C.; Elkamel, A.

2009-01-01

The economies of the developed world are increasingly including green technologies and processes that consider social, environmental and economic consequences. Hybrid electric vehicles and other fuel-efficient vehicle types can supply consumers with vehicles that decrease their ecological footprint and reduce the cost of fuel. However, one of the societal concerns often overlooked is the impact of alternative-fuel vehicle usage on the air quality in the urban environment. This paper presented a study that assessed the impact on air quality stemming from the operation of alternative fuel vehicles in urban environments. The study specifically focused on the province-wide emissions in Ontario and urban air pollution in the city of Toronto. The paper considered the life-cycle impacts of using alternative fuels for transportation purposes in terms of six major stressors for climate change, acidification and urban air quality. The two types of vehicles that were studied were plug-in hybrid electric vehicles (PHEVs) and fuel cell vehicles. Modeling of the penetration rates for both types of vehicles was completed based on the maximum capacity of the electrical grid including planned improvements. The scope of the study and discussion of health effects was first presented followed by data gathering and usage, methodology, results of supportable penetration and vehicle growth, and pollution abatement results. It was concluded that fuel cell vehicles have an advantage over, or near-equality with, PHEVs in almost every aspect of their emissions. 13 refs., 2 tabs., 10 figs

Allowable spent LWR fuel storage temperatures in inert gases, nitrogen, and air

International Nuclear Information System (INIS)

Gilbert, E.R.; Cunningham, M.E.; Simonen, E.P.; Thomas, L.E.; Campbell, T.K.; Barnhart, D.M.

1990-01-01

Spent fuel in inert dry storage is now a reality in the US; recommended maximum temperature-time conditions are specified in an IBM PC-compatible code. However, spent fuel cannot yet be stored in air because the data and theory needed for predicting allowable temperatures are still being developed. Tests to determine the behavior of spent UO 2 fragments and breached rod specimens in air are providing data that will be used to determine the temperatures that can be allowed for fuel stored in air. 13 refs., 5 figs

Interactive Effect of Air-Water Ratio and Temperature on the Air ...

African Journals Online (AJOL)

Windows User

KEYWORDS: Interactive effect, air-water ratio, temperature, volatile organic compounds, removal efficiency. [Received ... The rate of mass transfer of a VOC from wastewater to the ... where ΔHo is heat of evaporation of 1 mole of component.

Higher fuel prices are associated with lower air pollution levels.

Science.gov (United States)

Barnett, Adrian G; Knibbs, Luke D

2014-05-01

Air pollution is a persistent problem in urban areas, and traffic emissions are a major cause of poor air quality. Policies to curb pollution levels often involve raising the price of using private vehicles, for example, congestion charges. We were interested in whether higher fuel prices were associated with decreased air pollution levels. We examined an association between diesel and petrol prices and four traffic-related pollutants in Brisbane from 2010 to 2013. We used a regression model and examined pollution levels up to 16 days after the price change. Higher diesel prices were associated with statistically significant short-term reductions in carbon monoxide and nitrogen oxides. Changes in petrol prices had no impact on air pollution. Raising diesel taxes in Australia could be justified as a public health measure. As raising taxes is politically unpopular, an alternative political approach would be to remove schemes that put a downward pressure on fuel prices, such as industry subsidies and shopping vouchers that give fuel discounts. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Novel Hybrid-Fuel Storage System of Compressed Air Energy for China

Directory of Open Access Journals (Sweden)

Wenyi Liu

2014-08-01

Full Text Available Compressed air energy storage (CAES is a large-scale technology that provides long-duration energy storage. It is promising for balancing the large-scale penetration of intermittent and dispersed sources of power, such as wind and solar power, into electric grids. The existing CAES plants utilize natural gas (NG as fuel. However, China is rich in coal but is deficient in NG; therefore, a hybrid-fuel CAES is proposed and analyzed in this study. Based on the existing CAES plants, the hybrid-fuel CAES incorporates an external combustion heater into the power generation subsystem to heat the air from the recuperator and the air from the high-pressure air turbine. Coal is the fuel for the external combustion heater. The overall efficiency and exergy efficiency of the hybrid-fuel CAES are 61.18% and 59.84%, respectively. Given the same parameters, the cost of electricity (COE of the hybrid-fuel CAES, which requires less NG, is $5.48/MW∙h less than that of the gas-fuel CAES. Although the proposed CAES requires a relatively high investment in the current electricity system in North China, the proposed CAES will be likely to become competitive in the market, provided that the energy supplies are improved and the large scale grid-connection of wind power is realized.

Numerical analysis on effect of aspect ratio of planar solid oxide fuel cell fueled with decomposed ammonia

Science.gov (United States)

Tan, Wee Choon; Iwai, Hiroshi; Kishimoto, Masashi; Brus, Grzegorz; Szmyd, Janusz S.; Yoshida, Hideo

2018-04-01

Planar solid oxide fuel cells (SOFCs) with decomposed ammonia are numerically studied to investigate the effect of the cell aspect ratio. The ammonia decomposer is assumed to be located next to the SOFCs, and the heat required for the endothermic decomposition reaction is supplied by the thermal radiation from the SOFCs. Cells with aspect ratios (ratios of the streamwise length to the spanwise width) between 0.130 and 7.68 are provided with the reactants at a constant mass flow rate. A parametric study is conducted by varying the cell temperature and fuel utility factor to investigate their effects on the cell performance in terms of the voltage efficiency. The effect of the heat supply to the ammonia decomposer is also studied. The developed model shows good agreement, in terms of the current-voltage curve, with the experimental data obtained from a short stack without parameter tuning. The simulation study reveals that the cell with the highest aspect ratio achieves the highest performance under furnace operation. On the other hand, the 0.750 aspect ratio cell with the highest voltage efficiency of 0.67 is capable of thermally sustaining the ammonia decomposers at a fuel utility of 0.80 using the thermal radiation from both sidewalls.

The option study of air shipment of DUPIC fuel elements to Canada

International Nuclear Information System (INIS)

Lee, H. H.; Park, J. J.; Shin, J. M.; Kim, J. H.; Yang, M. S.; Koo, J. H.

2003-01-01

KAERI developed a DUPIC nuclear fuel with the refabrication of spent PWR fuel discharged from domestic nuclear power plant by a dry process at M6 hot-cell in IMEF. To verify the performance of DUPIC nuclear fuel, irradiation test at operating conditions of commercially operating power plant is essential. Since the HANARO research reactor of KAERI does not have Fuel Test Loop(FTL) for irradiating nuclear fuel under high temperature and high pressure conditions, DUPIC fuel cannot be irradiated in the FTL of HANARO until about 2008. In the 13-th PRM among Korea, Canada, USA and IAEA, AECL proposed that KAERI fabricated DUPIC fuel can be irradiated in the FTL of the NRU research reactor without charge of neutrons. The transportation quantity of DUPIC fuel to Canada is 10 elements(about 6 kg). This transportation package is classified as the 7-th class according to 'recommendation on the transport of dangerous goods' made by the United Nations. Air shipment was investigated as a promising option because it is generally understood that air shipment is more appropriate than ship shipment for transportation of small quantity of nuclear materials from the perspectives of cost and transportation period. In case of air shipment, the IATA regulations have been more intensified since the July of 2001. To make matters worse, it becomes more difficult to get the ratification of corresponding authorities due to 9.11 terror. It was found that at present there is no proper air transportation cask for DUPIC fuel. So, air transportation is considered to be impossible. An alternative of using the exemption limit of fissile material was reviewed. Its results showed that in case of going via USA territory, approvals from US DOT should be needed. The approvals include shipping and cask approvals on technical cask testing. Furthermore, since passes through territories of Japan and Russia have to be done in case of using a regular air cargo from Korea to Canada, approvals from Russia and

Spent Fuel Ratio Estimates from Numerical Models in ALE3D

Energy Technology Data Exchange (ETDEWEB)

Margraf, J. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dunn, T. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-08-02

Potential threat of intentional sabotage of spent nuclear fuel storage facilities is of significant importance to national security. Paramount is the study of focused energy attacks on these materials and the potential release of aerosolized hazardous particulates into the environment. Depleted uranium oxide (DUO₂) is often chosen as a surrogate material for testing due to the unreasonable cost and safety demands for conducting full-scale tests with real spent nuclear fuel. To account for differences in mechanical response resulting in changes to particle distribution it is necessary to scale the DUO₂ results to get a proper measure for spent fuel. This is accomplished with the spent fuel ratio (SFR), the ratio of respirable aerosol mass released due to identical damage conditions between a spent fuel and a surrogate material like depleted uranium oxide (DUO₂). A very limited number of full-scale experiments have been carried out to capture this data, and the oft-questioned validity of the results typically leads to overly-conservative risk estimates. In the present work, the ALE3D hydrocode is used to simulate DUO₂ and spent nuclear fuel pellets impacted by metal jets. The results demonstrate an alternative approach to estimate the respirable release fraction of fragmented nuclear fuel.

Cruising in afterburner: Air force fuel use and emerging energy policy

International Nuclear Information System (INIS)

Lucia, David J.

2011-01-01

Operational and mission efficiency were estimated for Air Force fighters, bombers and transports from fuel use data from 2001 through 2008 as reported in the Air Force Total Cost of Ownership (AFTOC) database. This analysis estimated efficiency in terms of the best performance theoretically possible for each platform based upon the energy available in the fuel expended. Operational efficiency considered aircraft operations in general, without regard for the type of mission. Mission efficiency only considered use of allocated fuel for combat (non-training) sorties. The cost associated with fuel inefficiency of the combined fighter, bomber and tanker force were estimated based on the fiscal year 2008 costs of fuel, fully burdened to include the cost of aerial refueling. The total cost of operational inefficiency was estimated at $5 billion per year. The fully burdened cost of mission inefficiency added an additional $3.6 billion for a total per year cost estimate of $8.6 billion. This represents 21.5% of the $40 billion portion of the 2009 budget dedicated to modernization. A business case for force-structure change is presented, which describes how these cost savings can be leveraged for modernization. - Highlights: → I assess how efficiently the United States Air Force uses fuel for aviation. → I estimate the cost associated with fuel inefficiency. → Improved technology can dramatically improve fuel efficiency. → There is potentially a large cost savings associated with improved fuel efficiency. → I present a business case to leverage this cost savings for modernization.

PARAMETERS OF AIR FIRED BOILER FED WITH DIFFERENT TYPES OF FUEL

Directory of Open Access Journals (Sweden)

Katarzyna Joanna Gładyszewska-Fiedoruk

2016-09-01

Full Text Available The measurement and interpretation of indoor carbon dioxide CO2 concentration can provide information on building indoor air quality and ventilation. On the other hand, concentration of carbon monoxide CO can show as how combustion process run and if the boiler is safe. When there is not sufficient air available to complete the combustion process, some of the fuel is left unburned, resulting in inefficiency and undesirable emissions. An examination of the CO2 and CO concentration in boiler and interpretation results help to improve indoor air quality. The paper presents characteristics of concentration CO2 and CO depend on used fuel in tested boiler rooms. The concentration curves show how each fuel combustion affect the amount of CO2 and CO that is produced.

Air quality and use of natural gas fuels: Assessment of improvement

International Nuclear Information System (INIS)

Riva, A.; Andreetto, B.

1992-01-01

This paper describes the application of the ARICOM code in the evaluation of air pollution and air quality in the Italian district of Verona. The study compared the environmental effects resulting from the use of natural gas, diesel fuels and fuel oils in a variety of real and simulated consumption schemes involving different mixes of fuels for space heating, automobile operation and industrial processes. The Verona district was divided into one square kilometer sections and the exhaust emission data were utilized in a dispersion model to calculate ground level pollution concentration levels. Real condition scenario pollution concentration levels calculated with this code were validated by actual measurements taken with an air quality monitoring network. The results evidenced the reduction in sulfur oxide pollution levels which can be obtained with the increased use of natural gas

Progress of air-breathing cathode in microbial fuel cells

Science.gov (United States)

Wang, Zejie; Mahadevan, Gurumurthy Dummi; Wu, Yicheng; Zhao, Feng

2017-07-01

Microbial fuel cell (MFC) is an emerging technology to produce green energy and vanquish the effects of environmental contaminants. Cathodic reactions are vital for high electrical power density generated from MFCs. Recently tremendous attentions were paid towards developing high performance air-breathing cathodes. A typical air-breathing cathode comprises of electrode substrate, catalyst layer, and air-diffusion layer. Prior researches demonstrated that each component influenced the performance of air-breathing cathode MFCs. This review summarized the progress in development of the individual component and elaborated main factors to the performance of air-breathing cathode.

Indoor air pollution from unprocessed solid fuels in developing countries.

Science.gov (United States)

Kaplan, Charlotte

2010-01-01

Approximately half of the world's population relies on biomass (primarily wood and agricultural residues) or coal fuels (collectively termed solid fuels) for heating, lighting, and cooking. The incomplete combustion of such materials releases byproducts with well-known adverse health effects, hence increasing the risk of many diseases and death. Among these conditions are acute respiratory infections, chronic obstructive pulmonary disease, heart disease, stroke, lung cancer, cataracts and blindness, tuberculosis, asthma, and adverse pregnancy outcomes. The International Agency for Research on Cancer has classified the indoor combustion of coal emissions as Group 1, a known carcinogen to humans. Indoor air pollution exposure is greatest in individuals who live in rural developing countries. Interventions have been limited and show only mixed results. To reduce the morbidity and mortality from indoor air pollution, countermeasures have to be developed that are practical, efficient, sustainable, and economical with involvement from the government, the commercial sector, and individuals. This review focuses on the contribution of solid fuels to indoor air pollution.

Thorium utilization: conversion ratio and fuel needs in thermal reactors

International Nuclear Information System (INIS)

Oosterkamp, W.J.

1975-01-01

As a preparatory study for thorium utilization in thermal reactors a study has been made of the fuel comsumption in existing reactor types. A quantitative description is given of the influence of enrichment, burnup, amount of structural material, choise of coolant and control requirements on the convertion ratio. The enrichment is an important factor and a low fuel comsumption can be achieved by increasing the enrichment

Development of an instantaneous local fuel-concentration measurement probe: an engine application

Science.gov (United States)

Guibert, P.; Boutar, Z.; Lemoyne, L.

2003-11-01

This work presents a new tool which can deliver instantaneous local measurements of fuel concentration in an engine cylinder with a high temporal resolution, particularly during compression strokes. Fuel concentration is represented by means of equivalence fuel-air ratio, i.e. the real engine mass ratio of fuel to air divided by the same ratio in ideal stoichiometry conditions. Controlling the mixture configuration for any strategy in a spark ignition engine and for auto-ignition combustion has a dominant effect on the subsequent processes of ignition, flame propagation and auto-ignition combustion progression, pollutant formation under lean or even stoichiometric operating conditions. It is extremely difficult, under a transient operation, to control the equivalence air/fuel ratio precisely at a required value and at the right time. This requires the development of a highly accurate equivalence air/fuel ratio control system and a tool to measure using crank angle (CA) resolution. Although non-intrusive laser techniques have considerable advantages, they are most of the time inappropriate due to their optical inaccessibility or the complex experimental set-up involved. Therefore, as a response to the demand for a relatively simple fuel-concentration measurement system a probe is presented that replaces a spark plug and allows the engine to run completely normally. The probe is based on hot-wire like apparatus, but involves catalytic oxidation at the wire surface. The development, characteristics and calibration of the probe are presented followed by applications to in-cylinder engine measurements.

THE EFFECT OF VARIABLE COMPRESSION RATIO ON FUEL CONSUMPTION IN SPARK IGNITION ENGINES

Directory of Open Access Journals (Sweden)

Yakup SEKMEN

2002-02-01

Full Text Available Due to lack of energy sources in the world, we are obliged to use our current energy sources in the most efficient way. Therefore, in the automotive industry, research works to manufacture more economic cars in terms of fuelconsumption and environmental friendly cars, at the same time satisfying the required performance have been intensively increasing. Some positive results have been obtained by the studies, aimed to change the compression ratio according to the operating conditions of engine. In spark ignition engines in order to improve the combustion efficiency, fuel economy and exhaust emission in the partial loads, the compression ratio must be increased; but, under the high load and low speed conditions to prevent probable knock and hard running compression ratio must be decreased slightly. In this paper, various research works on the variable compression ratio with spark ignition engines, the effects on fuel economy, power output and thermal efficiency have been investigated. According to the results of the experiments performed with engines having variable compression ratio under the partial and mid-load conditions, an increase in engine power, a decrease in fuel consumption, particularly in partial loads up to 30 percent of fuel economy, and also severe reductions of some exhaust emission values were determined.

Experimental study on the natural gas dual fuel engine test and the higher the mixture ratio of hydrogen to natural gas

Energy Technology Data Exchange (ETDEWEB)

Kim, B.S.; Lee, Y.S.; Park, C.K. [Cheonnam University, Kwangju (Korea); Masahiro, S. [Kyoto University, Kyoto (Japan)

1999-05-28

One of the unsolved problems of the natural gas dual fuel engine is that there is too much exhaust of Total Hydrogen Carbon(THC) at a low equivalent mixture ratio. To fix it, a natural gas mixed with hydrogen was applied to engine test. The results showed that the higher the mixture ratio of hydrogen to natural gas, the higher the combustion efficiency. And when the amount of the intake air is reached to 90% of WOT, the combustion efficiency was promoted. But, like a case making the injection timing earlier, the equivalent mixture ratio for the nocking limit decreases and the produce of NOx increases. 5 refs., 9 figs., 1 tab.

Air Shipment of Highly Enriched Uranium Spent Nuclear Fuel from Romania

Energy Technology Data Exchange (ETDEWEB)

K. J. Allen; I. Bolshinsky; L. L. Biro; M. E. Budu; N. V. Zamfir; M. Dragusin

2010-07-01

Romania safely air shipped 23.7 kilograms of Russian origin highly enriched uranium (HEU) spent nuclear fuel from the VVR S research reactor at Magurele, Romania, to the Russian Federation in June 2009. This was the world’s first air shipment of spent nuclear fuel transported in a Type B(U) cask under existing international laws without special exceptions for the air transport licenses. This shipment was coordinated by the Russian Research Reactor Fuel Return Program (RRRFR), part of the U.S. Department of Energy Global Threat Reduction Initiative (GTRI), in cooperation with the Romania National Commission for Nuclear Activities Control (CNCAN), the Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH), and the Russian Federation State Corporation Rosatom. The shipment was transported by truck to and from the respective commercial airports in Romania and the Russian Federation and stored at a secure nuclear facility in Russia where it will be converted into low enriched uranium. With this shipment, Romania became the 3rd country under the RRRFR program and the 14th country under the GTRI program to remove all HEU. This paper describes the work, equipment, and approvals that were required to complete this spent fuel air shipment.

Air Shipment of Highly Enriched Uranium Spent Nuclear Fuel from Romania

International Nuclear Information System (INIS)

Allen, K.J.; Bolshinsky, I.; Biro, L.L.; Budu, M.E.; Zamfir, N.V.; Dragusin, M.

2010-01-01

Romania safely air shipped 23.7 kilograms of Russian-origin highly enriched uranium (HEU) spent nuclear fuel from the VVR-S research reactor at Magurele, Romania, to the Russian Federation in June 2009. This was the world's first air shipment of spent nuclear fuel transported in a Type B(U) cask under existing international laws without special exceptions for the air transport licenses. This shipment was coordinated by the Russian Research Reactor Fuel Return Program (RRRFR), part of the U.S. Department of Energy Global Threat Reduction Initiative (GTRI), in cooperation with the Romania National Commission for Nuclear Activities Control (CNCAN), the Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH), and the Russian Federation State Corporation Rosatom. The shipment was transported by truck to and from the respective commercial airports in Romania and the Russian Federation and stored at a secure nuclear facility in Russia where it will be converted into low enriched uranium. With this shipment, Romania became the 3. country under the RRRFR program and the 14. country under the GTRI program to remove all HEU. This paper describes the work, equipment, and approvals that were required to complete this spent fuel air shipment. (authors)

Air humidity and water pressure effects on the performance of air-cathode microbial fuel cell cathodes

KAUST Repository

Ahn, Yongtae; Zhang, Fang; Logan, Bruce E.

2014-01-01

To better understand how air cathode performance is affected by air humidification, microbial fuel cells were operated under different humidity conditions or water pressure conditions. Maximum power density decreased from 1130 ± 30 mW m-2 with dry

Closed loop engine control for regulating NOx emissions, using a two-dimensional fuel-air curve

Science.gov (United States)

Bourn, Gary D.; Smith, Jack A.; Gingrich, Jess W.

2007-01-30

An engine control strategy that ensures that NOx emissions from the engine will be maintained at an acceptable level. The control strategy is based on a two-dimensional fuel-air curve, in which air manifold pressure (AMP) is a function of fuel header pressure and engine speed. The control strategy provides for closed loop NOx adjustment to a base AMP value derived from the fuel-air curve.

Determination of Light Water Reactor Fuel Burnup with the Isotope Ratio Method

International Nuclear Information System (INIS)

Gerlach, David C.; Mitchell, Mark R.; Reid, Bruce D.; Gesh, Christopher J.; Hurley, David E.

2007-01-01

For the current project to demonstrate that isotope ratio measurements can be extended to zirconium alloys used in LWR fuel assemblies we report new analyses on irradiated samples obtained from a reactor. Zirconium alloys are used for structural elements of fuel assemblies and for the fuel element cladding. This report covers new measurements done on irradiated and unirradiated zirconium alloys, Unirradiated zircaloy samples serve as reference samples and indicate starting values or natural values for the Ti isotope ratio measured. New measurements of irradiated samples include results for 3 samples provided by AREVA. New results indicate: 1. Titanium isotope ratios were measured again in unirradiated samples to obtain reference or starting values at the same time irradiated samples were analyzed. In particular, 49Ti/48Ti ratios were indistinguishably close to values determined several months earlier and to expected natural values. 2. 49Ti/48Ti ratios were measured in 3 irradiated samples thus far, and demonstrate marked departures from natural or initial ratios, well beyond analytical uncertainty, and the ratios vary with reported fluence values. The irradiated samples appear to have significant surface contamination or radiation damage which required more time for SIMS analyses. 3. Other activated impurity elements still limit the sample size for SIMS analysis of irradiated samples. The sub-samples chosen for SIMS analysis, although smaller than optimal, were still analyzed successfully without violating the conditions of the applicable Radiological Work Permit

Effect of air preheat temperature on the MILD combustion of syngas

International Nuclear Information System (INIS)

Huang, Mingming; Zhang, Zhedian; Shao, Weiwei; Xiong, Yan; Liu, Yan; Lei, Fulin; Xiao, Yunhan

2014-01-01

Highlights: • MILD combustion is achieved with reaction zone covering the entire combustion chamber. • Critical equivalence ratio for the occurrence of MILD combustion is identified. • MILD regime can be established for syngas fuel under air preheating conditions. - Abstract: The effect of air preheat temperature on MILD (Moderate or Intense Low-oxygen Dilution) combustion of coal-derived syngas was examined in parallel jet forward flow combustor. The results were presented on flow field using numerical simulations and on global flame signatures, OH ∗ radicals distribution and exhaust emissions using experiments. The discrete and high speed air/fuel injections into the combustor is necessary for the establishment of MILD conditions, because they cause strong gas recirculation and form large mixing region between the air and fuel jets. The critical equivalence ratio above which MILD combustion occurred was identified. The MILD regime was established for syngas fuel under air preheating conditions with lean operational limit and suppressed NO x and CO emissions. In the MILD combustion regime, the air preheating resulted in higher NO x but lower CO emissions, while the increase of equivalence ratio led to the increase of NO x and the decrease of CO emissions

Tamanu oil. An alternative fuel for variable compression ratio engine

Energy Technology Data Exchange (ETDEWEB)

Raj, Mohan T. [SASTRA Univ., Thanjavur, Tamilnadu (India). Dept. of Mechanical Engineering; Kandasamy, Murugumohan Kumar K. [Pavendar Bharathidasan College of Engineering and Technology, Trichy, Tamilnadu (India). Dept. of Mechanical Engineering

2012-11-01

Biodiesel can be produced from vegetable oils and also from waste fats. Biodiesel is a monoalkyl- ester of long chain fatty acids derived from renewable feedstock such as vegetable oils by transesterification process. The esterified cotton seed oil, pungam oil, rice bran oil, and tamanu oil are chosen as the alternative fuels. Among these oils, tamanu oil is considered for the first time as an alternative fuel. An experiment is conducted to obtain the operating characteristics of the variable compression ratio (VCR) engine run by chosen esterified oils, and the results are compared with esterified tamanu oil. From the comparison of results, it is inferred that the engine performance is improved with significant reduction in emissions for the chosen oils without any engine modification. The effective compression ratio can be fixed based on the experimental results obtained in the engine since the findings of the present research work infer that the biodiesel obtained from tamanu oil is a promising alternative fuel for direct-injection four-stroke VCR engine. (orig.)

A comparative study of emission motorcycle with gasoline and CNG fuel

Science.gov (United States)

Sasongko, M. N.; Wijayanti, W.; Rahardja, R. A.

2016-03-01

A comparison of the exhaust emissions of the engine running gasoline and Compressed Natural Gas have been performed in this study. A gasoline engine 4 stroke single-cylinder with volume of 124.8 cc and compression ratio of 9.3:1 was converted to a CNG gaseous engine. The fuel injector was replaced with a solenoid valve system for injecting CNG gas to engine. The concentrations of CO, CO2, O2 and HC in the exhaust gas of engine were measured over the range of fuel flow rate from 25.32 mg/s to 70.22 mg/s and wide range of Air Fuel Ratio. The comparative analysis of this study showed that CNG engine has a lower HC, CO2 and CO emission at the stoichiometry mixture of fuel and air combustion. The emissions increased when the Air-Fuel ratio was switched from the stoichiometry condition. Moreover, CNG engine produced a lower HC and CO emission compared to the gasoline for difference air flow rate. The average of HC and CO emissions of the CNG was 92 % and 78 % lower than that of the gasoline

Results of Am isotopic ratio analysis in irradiated MOX fuels

Energy Technology Data Exchange (ETDEWEB)

Koyama, Shin-ichi; Osaka, Masahiko; Mitsugashira, Toshiaki; Konno, Koichi [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center; Kajitani, Mikio

1997-04-01

For analysis of a small quantity of americium, it is necessary to separate from curium which has similar chemical property. As a chemical separation method for americium and curium, the oxidation of americium with pentavalent bismuth and subsequent co-precipitation of trivalent curium with BIP O{sub 4} were applied to analyze americium in irradiated MOX fuels which contained about 30wt% plutonium and 0.9wt% {sup 241}Am before irradiation and were irradiated up to 26.2GWd/t in the experimental fast reactor Joyo. The purpose of this study is to measure isotopic ratio of americium and to evaluate the change of isotopic ratio with irradiation. Following results are obtained in this study. (1) The isotopic ratio of americium ({sup 241}Am, {sup 242m}Am and {sup 243}Am) can be analyzed in the MOX fuels by isolating americium. The isotopic ratio of {sup 242m}Am and {sup 243}Am increases up to 0.62at% and 0.82at% at maximum burnup, respectively, (2) The results of isotopic analysis indicates that the contents of {sup 241}Am decreases, whereas {sup 242m}Am, {sup 243}Am increase linearly with increasing burnup. (author)

Influence of oxygen-metal ratio on mixed-oxide fuel performance

International Nuclear Information System (INIS)

Lawrence, L.A.; Leggett, R.D.

1979-04-01

The fuel oxygen-to-metal ratio (O/M) is recognized as an important consideration for performance of uranium--plutonium oxide fuels. An overview of the effects of differing O/M's on the irradiation performance of reference design mixed-oxide fuel in the areas of chemical and mechanical behavior, thermal performance, and fission gas behavior is presented. The pellet fuel has a nominal composition of 75 wt% UO 2 + 25 wt% PuO 2 at a pellet density of approx. 90% TD. for nominal conditions this results in a smeared density of approx. 85%. The cladding in all cases is 20% CW type 316 stainless steel with an outer diameter of 5.84 to 6.35 mm. O/M has been found to significantly influence fuel pin chemistry, mainly FCCI and fission product and fuel migration. It has little effect on thermal performance and overall mechanical behavior or fission gas release. The effects of O/M (ranging from 1.938 to 1.984) in the areas of fuel pin chemistry, to date, have not resulted in any reduction in fuel pin performance capability to goal burnups of approx. 8 atom% or more

Fluid flow and fuel-air mixing in a motored two-dimensional Wankel rotary engine

Science.gov (United States)

Shih, T. I.-P.; Nguyen, H. L.; Stegeman, J.

1986-01-01

The implicit-factored method of Beam and Warming was employed to obtain numerical solutions to the conservation equations of mass, species, momentum, and energy to study the unsteady, multidimensional flow and mixing of fuel and air inside the combustion chambers of a two-dimensional Wankel rotary engine under motored conditions. The effects of the following engine design and operating parameters on fluid flow and fuel-air mixing during the intake and compression cycles were studied: engine speed, angle of gaseous fuel injection during compression cycle, and speed of the fuel leaving fuel injector.

Study of the equilibrium of air-blown gasification of biomass to coal evolution fuels

International Nuclear Information System (INIS)

Biagini, Enrico

2016-01-01

Highlights: • Equilibrium model validated for coals, torrefied/green biomasses, in different gasifiers. • Maps of syngas composition, LHV and CGE for ER = 0–0.6, T = 500–2000 K, EBP = 0.004–0.158. • Effect of unconverted carbon, fuel moisture and overoxidation quantified. • Parameters for the maximum efficiency determined as functions of EBP. • EBP proven to be a good parameter for the quantitative comparison of different fuels. - Abstract: A non-stoichiometric equilibrium model based on the minimization of the Gibbs free energy was used to study the isothermal and adiabatic air-blown gasification of solid fuels on a carbonization curve from fossil (hard/brown coals, peat) to renewable (green biomasses and cellulose) fuels, including torrefied biofuels. The maps of syngas composition, heating value and process efficiency were provided as functions of equivalent ratio (oxygen-to-fuel ratio) in the range 0–0.6, temperature in 500–2000 K, and a fuel parameter, which allowed different cases to be quantitatively compared. The effect of fuel moisture, unconverted carbon and conditions to limit the tar formation was also studied. Cold gas efficiency >0.75 can be achieved for coals at high temperature, using entrained beds (which give low unconverted carbon), and improved by moisture/added steam. The bigger efficiency of green biomasses is only potential, as the practical limits (high temperature required to limit tar formation, moisture content and unconverted carbon in small gasifiers) strongly reduce the gasification performance. Torrefied biomasses (and plastics having an intermediate fuel parameter between coals and green biomasses) can attain high efficiency also in real conditions. The results shown in this work can be useful to evaluate the most promising feedstock (depending on its composition and possible pre-treatment/upgrading), define the operating conditions for maximizing the syngas heating value or the global efficiency, assess the

Nuclear fuel, mass balances, conversion ratio, doubling time, and uncertainty

International Nuclear Information System (INIS)

Vondy, D.R.

1976-11-01

Information on the performance aspects of nuclear power plants is presented concerning conversion ratio, criticality, primitive economic analysis, stable breeder-converter industry, doubling time, breeder industry economic benefit, defining nuclear fuel, recommendations, and uncertainty

Influence of fuel ratios on auto combustion synthesis of barium ferrite

Indian Academy of Sciences (India)

Abstract. Single-domain barium ferrite nano particles have been synthesized with narrow particle-size distribution using an auto combustion technique. In this process, citric acid was used as a fuel. Ratios of cation to fuel were maintained variously at 1 : 1, 1 : 2 and 1 : 3. The pH was 7 in all cases. Of all three cases, a cation ...

A COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF AIR FLOW THROUGH A TELECOM BACK-UP UNIT POWERED BY AN AIR-COOLED PROTON EXCHANGE MEMBRANE FUEL CELL

DEFF Research Database (Denmark)

Gao, Xin; Berning, Torsten; Kær, Søren Knudsen

2016-01-01

Proton exchange membrane fuel cells (PEMFC’s) are currently being commercialized for various applications ranging from automotive to stationary such as powering telecom back-up units. In PEMFC’s, oxygen from air is internally combined with hydrogen to form water and produce electricity and heat....... This product heat has to be effectively removed from the fuel cell, and while automotive fuel cells are usually liquid-cooled using a secondary coolant loop similar to the internal combustion engines, stationary fuel cell systems as they are used for telecom back-up applications often rely on excessive air fed...... to the fuel cell cathode to remove the heat. Thereby, the fuel cell system is much simpler and cheaper while the fuel cell performance is substantially lower compared to automotive fuel cells. This work presents a computational fluid dynamics analysis on the heat management of an air-cooled fuel cell powered...

Fossil fuels and air pollution in USA after the Clean Air Act

International Nuclear Information System (INIS)

Chuveliov, A.V.

1990-01-01

This paper addresses environmental issues in the USA after the Clean Air Act. Economic damage assessment to population and environment due to air pollution from stationary and mobile sources producing and utilizing fossil fuels in the USA for the period of 1970--1986 is determined and discussed. A comparison of environmental damage assessments for the USA and USSR is provided. The paper also addresses ecologo-economical aspects of hydrogen energy and technology. The effectiveness of hydrogen use in ferrous metallurgy and motor vehicles in the USA is determined and discussed

Concentration ratio of radon progeny in air

International Nuclear Information System (INIS)

Kobayashi, Tsuneo

2000-01-01

Investigations have been made on the concentration ratio of radon progeny in air. Data have been acquired intermittently since 1988 using alpha spectroscopic method around the author's office that is located in the northeastern part of Japan. Clarifying the behavior of radon progeny is an issue of wide importance to radiation protection, predicting earthquakes, etc. Let Rabc=ECRn(RaA)/{ECRn(RaB) + ECRn(RaC)}; the concentration ratio, Rabc, is relevant to the stability of the air. Statistical and time series analyses indicated several interesting results. To examine the log-normal distribution, Lilliefors test was made for logarithm of outdoor data every one year. Rabc passed the test 6 times for 9 years, while Radon progeny passed 8 times. Outdoor data indicated that the value of Rabc was lower in the morning, in other world, the air was more stable in the morning than in the afternoon. To see the seasonal variation, one-way layout analysis was made for four groups of data, i.e., spring (March to May), summer (June to August), autumn (September to November), and winter (December to February). Rabc indicated significantly higher level in spring and winter, in other word, air was stable in summer and autumn. Time series analysis was made for various variables; power spectra were estimated with autoregressive model that is equivalent to maximum entropy method. Power spectrum for Rabc was most similar to that of wind speed. One-year period, that is always remarkable for radon progeny, was not significant for Rabc. Three- to nine-day periods were often seen for Rabc, radon progeny, wind speed, and atmospheric pressure. These several-day periods are probably attributed to the passage of air masses. Twenty-day to thirty-day peak may be attributed to meteorological phenomena corresponding to the rotation period of the sun. Temperature indicated no significant periodicity except overwhelming one-year period. Wind speed is well known to affect the radon progeny concentration

Performance and emission comparison of a supercharged dual-fuel engine fueled by producer gases with varying hydrogen content

Energy Technology Data Exchange (ETDEWEB)

Mohon Roy, Murari [Rajshahi University of Engineering and Technology (JSPS Research Fellow, Okayama University), Tsushima-Naka 3, Okayama 700-8530 (Japan); Department of Mechanical Engineering, Okayama University, Tsushima-Naka 3, Okayama 700-8530 (Japan); Tomita, Eiji; Kawahara, Nobuyuki; Harada, Yuji [Department of Mechanical Engineering, Okayama University, Tsushima-Naka 3, Okayama 700-8530 (Japan); Sakane, Atsushi (Mitsui Engineering and Shipbuilding Co. Ltd., 6-4 Tsukiji 5-chome, Chuo-ku, Tokyo)

2009-09-15

This study investigated the effect of hydrogen content in producer gas on the performance and exhaust emissions of a supercharged producer gas-diesel dual-fuel engine. Two types of producer gases were used in this study, one with low hydrogen content (H{sub 2} = 13.7%) and the other with high hydrogen content (H{sub 2} = 20%). The engine was tested for use as a co-generation engine, so power output while maintaining a reasonable thermal efficiency was important. Experiments were carried out at a constant injection pressure and injection quantity for different fuel-air equivalence ratios and at various injection timings. The experimental strategy was to optimize the injection timing to maximize engine power at different fuel-air equivalence ratios without knocking and within the limit of the maximum cylinder pressure. Two-stage combustion was obtained; this is an indicator of maximum power output conditions and a precursor of knocking combustion. Better combustion, engine performance, and exhaust emissions (except NO{sub x}) were obtained with the high H{sub 2}-content producer gas than with the low H{sub 2}-content producer gas, especially under leaner conditions. Moreover, a broader window of fuel-air equivalence ratio was found with highest thermal efficiencies for the high H{sub 2}-content producer gas. (author)

Ground measurements of fuel and fuel consumption from experimental and operational prescribed fires at Eglin Air Force Base, Florida

Science.gov (United States)

Roger D. Ottmar; Robert E. Vihnanek; Clinton S. Wright; Andrew T. Hudak

2014-01-01

Ground-level measurements of fuel loading, fuel consumption, and fuel moisture content were collected on nine research burns conducted at Eglin Air Force Base, Florida in November, 2012. A grass or grass-shrub fuelbed dominated eight of the research blocks; the ninth was a managed longleaf pine (Pinus palustrus) forest. Fuel loading ranged from 1.7 Mg ha-1 on a...

Class B Fire-Extinguishing Performance Evaluation of a Compressed Air Foam System at Different Air-to-Aqueous Foam Solution Mixing Ratios

Directory of Open Access Journals (Sweden)

Dong-Ho Rie

2016-06-01

Full Text Available The purpose of this research is to evaluate the fire-extinguishing performance of a compressed air foam system at different mixing ratios of pressurized air. In this system, compressed air is injected into an aqueous solution of foam and then discharged. The experimental device uses an exclusive fire-extinguishing technology with compressed air foam that is produced based on the Canada National Laboratory and UL (Underwriters Laboratories 162 standards, with a 20-unit oil fire model (Class B applied as the fire extinguisher. Compressed air is injected through the air mixture, and results with different air-to-aqueous solution foam ratios of 1:4, 1:7, and 1:10 are studied. In addition, comparison experiments between synthetic surfactant foam and a foam type which forms an aqueous film are carried out at an air-to-aqueous solution foam ratio of 1:4. From the experimental results, at identical discharging flows, it was found that the fire-extinguishing effect of the aqueous film-forming foam is greatest at an air-to-aqueous solution foam ratio of 1:7 and weakest at 1:10. Moreover, the fire-extinguishing effect of the aqueous film-forming foam in the comparison experiments between the aqueous film-forming foam and the synthetic surfactant foam is greatest.

Effect of Temperature, Pressure and Equivalence Ratio on Ignition Delay in Ignition Quality Tester (IQT): Diesel,n-Heptane, andiso-Octane Fuels under Low Temperature Conditions

KAUST Repository

Yang, Seung Yeon

2015-11-02

Effects of temperature, pressure and global equivalence ratio on total ignition delay time in a constant volume spray combustion chamber were investigated for diesel fuel along with the primary reference fuels (PRFs) of n-heptane and iso-octane in relatively low temperature conditions to simulate unsteady spray ignition behavior. A KAUST Research ignition quality tester (KR-IQT) was utilized, which has a feature of varying temperature, pressure and equivalence ratio using a variable displacement fuel pump. A gradient method was adopted in determining the start of ignition in order to compensate pressure increase induced by low temperature heat release. Comparison of this method with other existing methods was discussed. Ignition delay times were measured at various equivalence ratios (0.5-1.7) with the temperatures of initial charge air in the range from 698 to 860 K and the pressures in the range of 1.5 to 2.1 MPa, pertinent to low temperature combustion (LTC) conditions. An attempt to scale the effect of pressure on total ignition delay was undertaken and the equivalence ratio exponent and activation energy in the Arrhenius expression of total ignition delay were determined. Ignition delay results indicated that there were strong correlations of pressure, temperature, and equivalence ratio under most conditions studied except at relatively low pressures. Diesel (DCN 52.5) and n-heptane (DCN 54) fuels exhibited reasonably similar ignition delay characteristics, while iso-octane showed a distinct behavior under low temperature regime having a two-stage ignition, which substantiate the adoption of the gradient method in determining ignition delay.

Numerical Investigation of Injection Timing Influence on Fuel Slip and Influence of Compression Ratio on Knock Occurrence in Conventional Dual Fuel Engine

Directory of Open Access Journals (Sweden)

Mario Sremec

2017-12-01

Full Text Available Compressed natural gas can be used in diesel engine with great benefits, but because of its low reactivity it is usually used in a so called dual fuel combustion process. Optimal parameters for dual fuel engines are not yet investigated thoroughly which is the motivation for this work. In this work, a numerical study performed in a cycle simulation tool (AVL Boost v2013 on the influence of different injection timings on fuel slip into exhaust and influence of compression ratio on knock phenomena in port injected dual fuel engine was conducted. The introduction of natural gas into the intake port of a diesel engine usually results in some fuel slipping into the exhaust port due to valve overlap. By analysing the simulation results, the injection strategy that significantly decreases the natural gas slip is defined. The knock occurrence study showed that the highest allowed compression ratio that will result in knock free operation of the presented engine is 18 for ambient intake condition, while for charged intake conditions the compression ratio should be lowered to 16.

Twisted Vanes Would Enhance Fuel/Air Mixing In Turbines

Science.gov (United States)

Nguyen, H. Lee; Micklow, Gerald J.; Dogra, Anju S.

1994-01-01

Computations of flow show performance of high-shear airblast fuel injector in gas-turbine engine enhanced by use of appropriately proportioned twisted (instead of flat) dome swirl vanes. Resultant more nearly uniform fuel/air mixture burns more efficiently, emitting smaller amounts of nitrogen oxides. Twisted-vane high-shear airblast injectors also incorporated into paint sprayers, providing advantages of low pressure drop characteristic of airblast injectors in general and finer atomization of advanced twisted-blade design.

Initiation of depleted uranium oxide and spent fuel testing for the spent fuel sabotage aerosol ratio program

Energy Technology Data Exchange (ETDEWEB)

Molecke, M.A.; Gregson, M.W.; Sorenson, K.B. [Sandia National Labs. (United States); Billone, M.C.; Tsai, H. [Argonne National Lab. (United States); Koch, W.; Nolte, O. [Fraunhofer Inst. fuer Toxikologie und Experimentelle Medizin (Germany); Pretzsch, G.; Lange, F. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (Germany); Autrusson, B.; Loiseau, O. [Inst. de Radioprotection et de Surete Nucleaire (France); Thompson, N.S.; Hibbs, R.S. [U.S. Dept. of Energy (United States); Young, F.I.; Mo, T. [U.S. Nuclear Regulatory Commission (United States)

2004-07-01

We provide a detailed overview of an ongoing, multinational test program that is developing aerosol data for some spent fuel sabotage scenarios on spent fuel transport and storage casks. Experiments are being performed to quantify the aerosolized materials plus volatilized fission products generated from actual spent fuel and surrogate material test rods, due to impact by a high energy density device, HEDD. The program participants in the U.S. plus Germany, France, and the U.K., part of the international Working Group for Sabotage Concerns of Transport and Storage Casks, WGSTSC have strongly supported and coordinated this research program. Sandia National Laboratories, SNL, has the lead role for conducting this research program; test program support is provided by both the U.S. Department of Energy and Nuclear Regulatory Commission. WGSTSC partners need this research to better understand potential radiological impacts from sabotage of nuclear material shipments and storage casks, and to support subsequent risk assessments, modeling, and preventative measures. We provide a summary of the overall, multi-phase test design and a description of all explosive containment and aerosol collection test components used. We focus on the recently initiated tests on ''surrogate'' spent fuel, unirradiated depleted uranium oxide, and forthcoming actual spent fuel tests. The depleted uranium oxide test rodlets were prepared by the Institut de Radioprotection et de Surete Nucleaire, in France. These surrogate test rodlets closely match the diameter of the test rodlets of actual spent fuel from the H.B. Robinson reactor (high burnup PWR fuel) and the Surry reactor (lower, medium burnup PWR fuel), generated from U.S. reactors. The characterization of the spent fuels and fabrication into short, pressurized rodlets has been performed by Argonne National Laboratory, for testing at SNL. The ratio of the aerosol and respirable particles released from HEDD-impacted spent

Cleaner fuels for the improvement of air quality

International Nuclear Information System (INIS)

Catani, R.; Marchionna, M.; Rossini, S.

1998-01-01

Harder standards of quality of the air and the consequent limits on the emissions involve the necessity to adopt various measures: programs for inspection/maintenance, technological advance on motors and catalytic mufflers and the reformulation of fuel. This last one is not the only solution but plays a remarkable role, because it has an immediate effect on the quality of the air. As result of that, the present paper explains the main variations that will regard the composition of ben zine and diesel oil

The influence of fuel-air swirl intensity on flame structures of syngas swirl-stabilized diffusion flame

Science.gov (United States)

Shao, Weiwei; Xiong, Yan; Mu, Kejin; Zhang, Zhedian; Wang, Yue; Xiao, Yunhan

2010-06-01

Flame structures of a syngas swirl-stabilized diffusion flame in a model combustor were measured using the OH-PLIF method under different fuel and air swirl intensity. The flame operated under atmospheric pressure with air and a typical low heating-value syngas with a composition of 28.5% CO, 22.5% H2 and 49% N2 at a thermal power of 34 kW. Results indicate that increasing the air swirl intensity with the same fuel, swirl intensity flame structures showed little difference except a small reduction of flame length; but also, with the same air swirl intensity, fuel swirl intensity showed great influence on flame shape, length and reaction zone distribution. Therefore, compared with air swirl intensity, fuel swirl intensity appeared a key effect on the flame structure for the model combustor. Instantaneous OH-PLIF images showed that three distinct typical structures with an obvious difference of reaction zone distribution were found at low swirl intensity, while a much compacter flame structure with a single, stable and uniform reaction zone distribution was found at large fuel-air swirl intensity. It means that larger swirl intensity leads to efficient, stable combustion of the syngas diffusion flame.

Durability and regeneration of activated carbon air-cathodes in long-term operated microbial fuel cells

Science.gov (United States)

Zhang, Enren; Wang, Feng; Yu, Qingling; Scott, Keith; Wang, Xu; Diao, Guowang

2017-08-01

The performance of activated carbon catalyst in air-cathodes in microbial fuel cells was investigated over one year. A maximum power of 1722 mW m-2 was produced within the initial one-month microbial fuel cell operation. The air-cathodes produced a maximum power >1200 mW m-2 within six months, but gradually became a limiting factor for the power output in prolonged microbial fuel cell operation. The maximum power decreased by 55% when microbial fuel cells were operated over one year due to deterioration in activated carbon air-cathodes. While salt/biofilm removal from cathodes experiencing one-year operation increased a limiting performance enhancement in cathodes, a washing-drying-pressing procedure could restore the cathode performance to its original levels, although the performance restoration was temporary. Durable cathodes could be regenerated by re-pressing activated carbon catalyst, recovered from one year deteriorated air-cathodes, with new gas diffusion layer, resulting in ∼1800 mW m-2 of maximum power production. The present study indicated that activated carbon was an effective catalyst in microbial fuel cell cathodes, and could be recovered for reuse in long-term operated microbial fuel cells by simple methods.

Thermodynamic modeling of LPG combustion in dual-fuel engines; Modelisation thermodynamique de la combustion du GPL dans les moteurs dual-fuel

Energy Technology Data Exchange (ETDEWEB)

Bilcan, A.; Le Corre, O.; Tazerout, M. [Ecole des Mines de Nantes, 44 (France); Ramesh, A. [Indian Institute of Technology Madras (India)

2002-07-01

Dual-fuel engines are modified diesel engines burning simultaneously two fuels inside the cylinder: a gaseous one, called the primary fuel and a liquid one, called the pilot fuel. The thermal efficiency of the dual-fuel engine and of the diesel engine are comparable; the level of emissions is lower compared to the diesel one. This article presents a new procedure for the combustion modeling in a LPG-diesel dual-fuel engine. The procedures deals with the ignition delay period and with the rate of heat release inside the cylinder. This procedure is validated using experimental data issued front a collaboration with the Indian Institute of Technology from Madras, India. The used engine is a single-cylinder one, air-cooled. The pilot fuel is direct injected inside the cylinder The engine was run at constant load and with different diesel substitutions, i.e. for different air to fuel ratios of the primary fuel-air mixture. The general error of the procedure is below 10%. (authors)

Fuelling clean air : municipal fuel purchasing policies that reduce emissions contributing to poor air quality and climate change

International Nuclear Information System (INIS)

Perrotta, K.

2003-03-01

Air quality can be improved by low sulphur fuels in two ways: through the direct reduction of sulphates, sulphur dioxide and PM; and by improving the effectiveness of existing emission control devices. This report examined three case studies involving the fuel purchasing policies in three Ontario municipalities: Toronto, Waterloo, and Brampton. Toronto favors purchasing conventional fuels with lower sulphur levels. Waterloo will purchase on-road diesel for its off-road diesel fleet; ultra low sulphur diesel (ULSD) for buses; and 10 per cent ethanol blended with 90 per cent gasoline (E10) for its gasoline-fuelled fleet. Brampton purchased 20 per cent biodiesel blended with 80 per cent on-road diesel (B20). Two approaches were examined for lowering emissions from gasoline fuelled vehicles: favouring gasoline with the lowest sulphur levels, and purchasing E10. It was recommended that the Greater Toronto Area (GTA) Clean Air Council look into: ownership of emissions trading credits created as a result of fuel purchasing policies; the benefits of, and mechanisms available for, pooling fuel purchases; and, establishing a subcommittee to monitor developments related to fuels, vehicles and emission control technologies. 48 refs., 18 tabs

A Piston Geometry and Nozzle Spray Angle Investigation in a DI Diesel Engine by Quantifying the Air-Fuel Mixture

Directory of Open Access Journals (Sweden)

Pavlos Dimitriou

2015-03-01

Full Text Available Low temperature diesel combustion has been widely investigated over the last few years for reducing in-cylinder emissions of Direct Injection (DI diesel engines without sacrificing efficiency and fuel consumption. The spatial distribution of the fuel within the combustion chamber and the air-fuel mixing quality are the key factors affecting temperature generation within the cylinder. Avoiding fuel rich areas within the cylinder can significantly reduce the local high temperatures resulting in low NOx formation. This paper investigates the effects of the combustion chamber geometry and spray angle on the air-fuel mixing and emissions formation of a DI diesel engine. A new quantitative factor measuring the air-fuel mixing quality has been adopted in order to analyze and compare air-fuel mixing quality for different piston geometries. The results have shown that pistons with a narrow entrance and a deep combustion re-entrant chamber benefit from increased air-fuel mixtures due to the significantly higher swirl generated within the cylinder. However, the improved air-fuel mixing does not consequently lead to a reduced NOx generation, which is highly affected by the combustion efficiency of the engine.

Laser induced fluorescence measurements of the mixing of fuel oil with air

Energy Technology Data Exchange (ETDEWEB)

Arnold, A; Bombach, R; Hubschmid, W; Kaeppeli, B [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

We report on measurements of the mixing of fuel oil with air at atmospheric pressure in an industrial premixed gas turbine burner. The concentration of the vaporized fuel oil was measured with laser induced fluorescence. We reason that the fuel oil concentration can be considered with good accuracy as proportional to the fluorescence intensity. (author) 6 fig., 3 refs.

Air and fuel supercharge in the performance of a diesel cycle engine

Directory of Open Access Journals (Sweden)

Marcelo Silveira de Farias

Full Text Available ABSTRACT: This paper aimed to evaluate the performance of a Diesel cycle engine, changing the configurations for the air and fuel supply system. Variables analyzed were torque, power, specific fuel consumption and thermal efficiency in four different engine configurations (aspirated, aspirated + service, turbocharged + service and turbocharged. For that, there were dynamometer experiments by power take-off of an agricultural tractor. The experimental outline used was entirely randomized, in a bifatorial design with three repetitions. Results indicated that the engine supercharge, compared to its original configuration, provided a significant increase of torque and power. Only the addition of turbo does not caused a significant effect in the engine performance. Application of turbocharger provides an improvement in the burning of the air/fuel mixture, which favors the increase of engine power and; consequently, reduced the specific fuel consumption.

Modeling and control of a proton exchange membrane fuel cell with the air compressor according to requested electrical current

Directory of Open Access Journals (Sweden)

Malekbala Mohammad Rahim

2015-01-01

Full Text Available The aim of this paper is to design and investigate the dynamic behavior of a PEM fuel cell system. Dynamic analysis of a PEM fuel cell system has been done in Matlab\\Simulink software according to electrical current that has been applied from hybrid system. In addition, dynamical fuel cell system has been explained according to oriented control that is started from air injection compressor model. Also hydrogen valve actuator has been controlled according to the compressor model. The results of the fuel cell dynamic model as well as the applied compressor model are fully validated based on the available results in the open literature. Finally, the effects of several operating parameters of the fuel cell system such as anode and cathode pressures, cell voltage, compressor voltage, compressor mass flow rate variation with respect to inlet pressure ratio, net and stack powers on the dynamic behavior of the hybrid system are investigated. The results show that the model can predict the dynamic behavior of the fuel cell system accurately and it can be used directly for any control purposes.

A portable system powered with hydrogen and one single air-breathing PEM fuel cell

International Nuclear Information System (INIS)

Fernández-Moreno, J.; Guelbenzu, G.; Martín, A.J.; Folgado, M.A.; Ferreira-Aparicio, P.; Chaparro, A.M.

2013-01-01

Highlights: • A portable system based on hydrogen and single air breathing PEM fuel cell. • Control electronics designed for low single cell voltage (0.5–0.8 V). • Forced air convection and anode purging required to help water management. • Application consisting of a propeller able to display a luminous message. • Up to 20 h autonomy with continuous 1.1 W consumption, using 1 g H 2 . - Abstract: A portable system for power generation based on hydrogen and a single proton exchange membrane fuel cell (PEMFC) has been built and operated. The fuel cell is fed in the anode with hydrogen stored in a metal hydrides cartridge, and in the cathode with oxygen from quiescent ambient air (‘air breathing’). The control electronics of the system performs DC–DC conversion from the low voltage (0.5–0.8 V) and high current output (200–300 mA cm −2 ) of the single fuel cell, up to 3.3 V to power an electronic application. System components assist fuel cell operation, including an electronic valve for anode purging, a fan in front of the open cathode, two supercapacitors for auxiliary power requirements, four LED lights, and a display screen. The influence of the system components on fuel cell behaviour is analyzed. The cathode fan and anodic purging help excess water removal from the electrodes leading to steadier cell response at the expense of extra power consumption. The power system is able to provide above 1 W DC electricity to an external application during 20 h using 1 g of H 2 . An application consisting of a propeller able to display a luminous message is chosen to test system. It is shown that one single air breathing PEM fuel cell powered with hydrogen may provide high energy density and autonomy for portable applications

Pure rotational CARS thermometry studies of low-temperature oxidation kinetics in air and ethene-air nanosecond pulse discharge plasmas

International Nuclear Information System (INIS)

Zuzeek, Yvette; Choi, Inchul; Uddi, Mruthunjaya; Adamovich, Igor V; Lempert, Walter R

2010-01-01

Pure rotational CARS thermometry is used to study low-temperature plasma assisted fuel oxidation kinetics in a repetitive nanosecond pulse discharge in ethene-air at stoichiometric and fuel lean conditions at 40 Torr pressure. Air and fuel-air mixtures are excited by a burst of high-voltage nanosecond pulses (peak voltage, 20 kV; pulse duration, ∼ 25 ns) at a 40 kHz pulse repetition rate and a burst repetition rate of 10 Hz. The number of pulses in the burst is varied from a few pulses to a few hundred pulses. The results are compared with the previously developed hydrocarbon-air plasma chemistry model, modified to incorporate non-empirical scaling of the nanosecond discharge pulse energy coupled to the plasma with number density, as well as one-dimensional conduction heat transfer. Experimental time-resolved temperature, determined as a function of the number of pulses in the burst, is found to agree well with the model predictions. The results demonstrate that the heating rate in fuel-air plasmas is much faster compared with air plasmas, primarily due to energy release in exothermic reactions of fuel with O atoms generated by the plasma. It is found that the initial heating rate in fuel-air plasmas is controlled by the rate of radical (primarily O atoms) generation and is nearly independent of the equivalence ratio. At long burst durations, the heating rate in lean fuel air-mixtures is significantly reduced when all fuel is oxidized.

Project of multiple controller models for the maintenance of air/fuel ratio in natural gas internal combustion motors; Projeto de controladores multiplos modelos para manutencao da relacao ar/combustivel em motores de combustao interna movidos a gas natural

Energy Technology Data Exchange (ETDEWEB)

Freitas Junior, Fernando Sousa e; Fleury, Agenor de Toledo [Sao Paulo Univ. SP (Brazil). Escola Politecnica. Dept. de Engenharia Mecanica]. E-mails: ffreitas@usp.br; agfleury@ipt.br

2006-07-01

The objective of this work is the study of advanced control techniques for the reduction of pollutant gases generated by internal combustion engines powered by natural gas. In this paper three techniques are applied to control the fuel injection and the ignition timing: the Generalized Predictive Control (GPC), the Linear Quadratic Regulator (LQR) and H{infinity} Control by Linear Matrix Inequalities (LMI). To each one of those techniques were developed a multiple model structure seeking to include the vast operation region of the engine. The controller's performance is measured by the efficiency in maintaining the fuel/air ratio around 1% of maximum deviation in relation to the stoichiometric value. The results show the possibility of controlling pollutant emission generated by this kind of engine to conform to international emission standards, improving life quality. (author)

Investigation of the Behavior of Fuel in the Intake Manifold and its Relation to S. I. Engines, 1980-1983

Science.gov (United States)

Servati, Hamid Beyragh

A liquid fuel film formation on the walls of an intake manifold adversely affects the engine performance and alters the overall air/fuel ratio from that scheduled by a fuel injector or carburetor and leads to adverse effects in vehicle driveability, exhaust emissions, and fuel economy. In this dissertation, the intake manifold is simulated by a horizontal circular duct. A model is provided to predict the rate of deposition and evaporation of the droplets in the intake manifold. The liquid fuel flow rate into the cylinders, mean film velocity and film thickness are determined as functions of engine parameters for both steady and transient operating conditions of the engine. A mathematical engine model is presented to simulate the dynamic interactions of the various engine components such as the air/fuel inlet element, intake manifold, combustion, dynamics and exhaust emissions. Inputs of the engine model are the intake manifold pressure and temperature, throttle angle, and air/fuel ratio. The observed parameters are the histories of fuel film thickness and velocity, fuel consumption, engine speed, engine speed hesitation time, and histories of CO, CO(,2), NO(,x), CH(,n), and O(,2). The effects of different air/fuel ratio control strategies on engine performance and observed parameters are also shown.

Risk of low birth weight and stillbirth associated with indoor air pollution from solid fuel use in developing countries.

Science.gov (United States)

Pope, Daniel P; Mishra, Vinod; Thompson, Lisa; Siddiqui, Amna Rehana; Rehfuess, Eva A; Weber, Martin; Bruce, Nigel G

2010-01-01

Exposure to indoor air pollution from solid fuel use (IAP) has been linked to approximately 1.5 million annual deaths (World Health Organization (http://www.who.int/indoorair/publications/fuelforlife/en/index.html)) due to acute lower respiratory infections in children effect meta-analyses (I(2) = 0%) found that IAP was associated with increased risk of percentage LBW (odds ratio = 1.38, 95% confidence interval: 1.25, 1.52) and stillbirth (odds ratio = 1.51, 95% confidence interval: 1.23, 1.85) and reduced mean birth weight (-95.6 g, 95% confidence interval: -68.5, -124.7). Evidence from secondhand smoke, ambient air pollution, and animal studies--and suggested plausible mechanisms--substantiate these associations. Because a majority of pregnant women in developing countries, where rates of LBW and stillbirth are high, are heavily exposed to IAP, increased relative risk translates into substantial population attributable risks of 21% (LBW) and 26% (stillbirth).

Air pollution and fuel vapour induced changes in lung functions: are fuel handlers safe?

Science.gov (United States)

Chawla, Anuj; Lavania, A K

2008-01-01

Automobile exhaust derived air pollutants have become a major health hazard. Coupled with the inhalation of fuel vapour, as occurs in petrol station workers, this may lead to significant impairment of lung function. Spirometric lung functions were studied in 58 petrol station workers to examine this possibility. The forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced expiratory flow 25%-75% (FEF25-75) and peak expiratory flow (PEF) were recorded and analysed separately for smokers and non-smokers. The workers were divided into 5 groups for analysis of data based on the number of years of work in the petrol pumps. Outdoor air analysis was also carried out. The FVC, FEV1 and PEF declined significantly with increasing years of work in petrol stations in both smokers and non-smokers. Smoking as an independent variable was found to affect the FEV1 significantly but not FVC or PEF. The FEF25-75 was found to be the most affected spirometric value with a significant reduction with increasing years of work. Smoking as such did not affect it. Oxides of nitrogen (NOx), suspended particulate matter (SPM) and particulate matter less than 10 microns (PM10) in outdoor air were higher than the national ambient air quality standards. Exposure to automobile exhaust and fuel vapour impairs lung function in a time-dependent manner. Cigarette smoking appears to accelerate the decline.

Experience of air transport of nuclear fuel material as type A package

International Nuclear Information System (INIS)

Kawasaki, Masashi; Kageyama, Tomio; Suzuki, Toru

2004-01-01

Special law on nuclear disaster countermeasures (hereafter called as to nuclear disaster countermeasures low) that is domestic law for dealing with measures for nuclear disaster, was enforced in June, 2000. Therefore, nuclear enterprise was obliged to report accidents as required by nuclear disaster countermeasures law, besides meeting the technical requirement of existent transport regulation. For overseas procurement of plutonium reference materials that are needed for material accountability, A Type package must be transported by air. Therefore, concept of air transport of nuclear fuel materials according to the nuclear disaster countermeasures law was discussed, and the manual including measures against accident in air transport was prepared for the oversea procurement. In this presentation, the concept of air transport of A Type package containing nuclear fuel materials according to the nuclear disaster countermeasures law, and the experience of a transportation of plutonium solution from France are shown. (author)

Polymer electrolyte fuel cells: flow field for efficient air operation

Energy Technology Data Exchange (ETDEWEB)

Buechi, F N; Tsukada, A; Haas, O; Scherer, G G [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

A new flow field was designed for a polymer electrolyte fuel cell stack with an active area of 200 cm{sup 2} for operation at low air stoichiometry and low air over pressure. Optimum of gas flow and channel dimensions were calculated based on the required pressure drop in the fluid. Single cells and a bi-cell stack with the new flow field show an improved current/voltage characteristic when operated at low air stoichiometries as compared to that of the previous non optimized design. (author) 4 figs., 3 refs.

Reformulated and alternative fuels: modeled impacts on regional air quality with special emphasis on surface ozone concentration.

Science.gov (United States)

Schell, Benedikt; Ackermann, Ingmar J; Hass, Heinz

2002-07-15

The comprehensive European Air Pollution and Dispersion model system was used to estimate the impacts of the usage of reformulated and alternative fuels on regional air quality with special emphasis on surface ozone concentrations. A severe western European summer smog episode in July 1994 has been used as a reference, and the model predictions have been evaluated for this episode. A forecast simulation for the year 2005 (TREND) has been performed, including the future emission development based on the current legislation and technologies available. The results of the scenario TREND are used as a baseline for the other 2005 fuel scenarios, including fuel reformulation, fuel sulfur content, and compressed natural gas (CNG) as an alternative fuel. Compared to the year 1994, significant reductions in episode peak ozone concentrations and ozone grid hours are predicted for the TREND scenario. These reductions are even more pronounced within the investigated alternative and reformulated fuel scenarios. Especially, low sulfur fuels are appropriate for an immediate improvement in air quality, because they effect the emissions of the whole fleet. Furthermore, the simulation results indicate that the introduction of CNG vehicles would also enhance air quality with respect to ozone.

Instrumentation of cars for fuel economy. Final report

Energy Technology Data Exchange (ETDEWEB)

Morris, J E

1982-04-01

The development of an electronic system to control the air-fuel ratio (A/F) and ignition timing of an internal combustion engine to optimize fuel economy is described. Dynamometer and drive cycle testing of the system was performed. The results showed that a significant improvement in fuel economy can be achieved by a control system of the type developed. It is clear, however, that considerably more work needs to be done. One area mentioned is the need for more systematic fuel economy testing against speed and load as control parameters are varied for optimization, and a more economic air bypass system must be developed. (LCL)

Cost and energy consumption estimates for the aluminum-air battery anode fuel cycle

Science.gov (United States)

1990-01-01

At the request of DOE's Office of Energy Storage and Distribution (OESD), Pacific Northwest Laboratory (PNL) conducted a study to generate estimates of the energy use and costs associated with the aluminum anode fuel cycle of the aluminum-air (Al-air) battery. The results of this analysis indicate that the cost and energy consumption characteristics of the mechanically rechargeable Al-air battery system are not as attractive as some other electrically rechargeable electric vehicle battery systems being developed by OESD. However, there are distinct advantages to mechanically rechargeable batteries, which may make the Al-air battery (or other mechanically rechargeable batteries) attractive for other uses, such as stand-alone applications. Fuel cells, such as the proton exchange membrane (PEM), and advanced secondary batteries may be better suited to electric vehicle applications.

Draining Water from Aircraft Fuel Using Nitrogen Enriched Air

Directory of Open Access Journals (Sweden)

Michael Frank

2018-04-01

Full Text Available This paper concerns a computational study of the process of removing water from an aircraft’s fuel tank by pumping nitrogen enriched air (NEA from the bottom of the tank. This is an important procedure for the smooth, efficient, and safe operation of the aircraft’s engine. Due to the low partial pressure of water in the pumped NEA, it absorbs water from the fuel. The water-laden bubbles enter the ullage, the empty space above the fuel, and escape into the environment. The effects of the number of NEA inlets and the NEA mass flow rate on the timescale of the NEA pumping were investigated using Computational Fluid Dynamics. The results reveal that the absorption of water by the NEA bubbles is low and is not affected by the number of the inlets used. Yet, the water content in the fuel decreases fast during the procedure, which is the desired outcome. We show that this is due to the relatively dry NEA entering the ullage and displacing the moist air, thus reducing the partial pressure of water at the fuel/ullage interface. This shift from equilibrium conditions forces water to evaporate from the fuel’s entire surface. Furthermore, the amount of water migrating from the fuel directly into the ullage is significantly greater than that absorbed by the rising bubbles. In turn, the rate of decrease of the water content in the ullage is determined by the total NEA mass flow rate and this is the dominant contributor to the draining time, with the number of NEA nozzles playing a minor role. We confirmed this by pumping NEA directly into the ullage, where we observe a significant decrease of water even when the NEA is not pumped through the fuel. We also show that doubling the mass flow rate halves the draining time. When considering the capability of most modern aircraft to pump NEA through the fuel as part of their inerting system, the proposed method for removing water is particularly attractive, requiring very little (if at all design modification.

Enthalpy analysis and Heat Exchanger Sizing of an Air-cooled Proton Exchange Membrane Fuel Cell System

DEFF Research Database (Denmark)

Gao, Xin; Berning, Torsten; Kær, Søren Knudsen

below -20 °C in the winter which make liquid-cooled fuel cells impossible. In such cases, air-cooled fuel cell systems are deployed where the air that is fed to the fuel cell serves both as reactant supplier and coolant to remove the waste heat that is generated during fuel cell operation. In some cases...... in order to optimize the operating conditions and the performance of such a system. The adjustable parameters include the fan speed that determines the amount of air that is brought into the system, and the size and rotating speed of the rotating enthalpy wheel. In addition, computational fluid dynamics...... or an ordinary heat exchanger can fulfill the heat recovery demand. Despite the fact that the air enters the stack at a cold temperature, even the forefront of the stack is at a much elevated and desired stack temperature with the help of supplying an acceptable amount of power to an electric stack heater. So...

Carbon isotope ratios of atmospheric carbon dioxide

International Nuclear Information System (INIS)

Sakai, Hitoshi; Kishima, Noriaki; Tsutaki, Yasuhiro.

1982-01-01

The delta 13 C values relative to PDB were measured for carbon dioxide in air samples collected at various parts of Japan and at Mauna Loa Observatory, Hawaii in the periods of 1977 and 1978. The delta 13 C values of the ''clean air'' are -7.6 % at Hawaii and -8.1 per mille Oki and Hachijo-jima islands. These values are definitely lighter than the carbon isotope ratios (-6.9 per mille) obtained by Keeling for clean airs collected at Southern California in 1955 to 1956. The increase in 12 C in atmospheric carbon dioxide is attributed to the input of the anthropogenic light carbon dioxides (combustion of fossil fuels etc.) Taking -7.6 per mille to be the isotope ratio of CO 2 in the present clean air, a simple three box model predicts that the biosphere has decreased rather than increased since 1955, implying that it is acting as the doner of carbon rather than the sink. (author)

Air pollution and economics: Alternate use of fuels in small scale industries

International Nuclear Information System (INIS)

Rao, B.P.S.; Pandit, V.I.

1999-01-01

In developing countries the problem of air pollution was recognized earlier, however, it has acquired a greater dimension due to the conventional use of low grade fuels like coal, baggase, rice husk, etc. having high sulphur and ash content. The industrial sources contribute about 30--40% of the total emissions. In India, the small scale industries (low investment group) contribute about 60--80% of the total industrial emissions. These industries are characterized with various environmental pollution problems due to cluster of small scale industries located in sensitive area; use of low grade fuel, primitive processing techniques without emission abatement facilities etc., thus leading to enormous pollution in an confined region. Acute need was felt to reduce the pollution problem associated with small scale industries by use of cleaner fuel so as to reduce the localized problem. The paper presents the emissions associated with use of coal/coke, natural gas, LPG, and propane along with the fuel cost for small scale industrial sector of Agra, Firozabad and Mathura region. The studies carried out would find applicability to meet the air pollution standards based on shift in fuel and associated cost

Fuel conversion efficiency and energy balance of a 400 kW{sub t} fluidized bed straw gasifier

Energy Technology Data Exchange (ETDEWEB)

Erguedenler, A.; Ghaly, A.E.; Hamdullahpur, F. [Technical Univ. of Nova Scotia, Halifax (Canada)

1993-12-31

A 400 kW (thermal) dual-distributor type fluidized bed gasifier developed for the energy recovery from cereal straw was used to investigate the effects of equivalence ratio (actual air-fuel ratio: stoichiometric air-fuel ratio), fluidization velocity and bed height on the fuel conversion efficiency from wheat straw. The energy balance was also performed on the system under those operating conditions. The results indicated that the equivalence ratio was the most significant parameter affecting the fuel conversion efficiency and the energy recovered from the straw in the form of gas. Both the fuel conversion efficiency and the energy recovery increased with increases in the equivalence ratio. The fluidization velocity and bed height had minimal effects on these parameters. A fuel conversion efficiency as high as 98% was obtained at the equivalence ratio of 0.35. The energy recovered in the form of gas and the sensible heat of the produced gas were in the ranges of 40--70% and 9--17%, respectively. Unaccounted losses showed a dramatic increase at lower equivalence ratios and were in the range of 6--53% depending on the operating condition.

Effect of compression ratio on performance, combustion and emission characteristics of a dual fuel diesel engine run on raw biogas

International Nuclear Information System (INIS)

Bora, Bhaskor J.; Saha, Ujjwal K.; Chatterjee, Soumya; Veer, Vijay

2014-01-01

Highlights: • Maximum brake thermal efficiency of 20.04% was obtained in dual fuel mode. • Compression ratio of 18 produced the maximum brake thermal efficiency. • Maximum replacement of diesel was found to be 79.46% at a compression ratio of 18. • CO gets reduced by 26.22% with the increase of compression ratio from 16 to18. • HC gets reduced by 41.97% with the increase of compression ratio from 16 to18. - Abstract: The energy consumption of the world is increasing at a staggering rate due to population explosion. The extensive use of energy has led to fossil fuel depletion and the rise in pollution. Renewable energy holds the key solution to these aforementioned problems. Biogas, one such renewable fuel, can be used in a diesel engine under dual fuel mode for the generation of power. This work attempts to unfold the effect of compression ratio on the performance, combustion and emission characteristics of a dual fuel diesel engine run on raw biogas. For this investigation, a 3.5 kW single cylinder, direct injection, water cooled, variable compression ratio diesel engine is converted into a biogas run dual fuel diesel engine by connecting a venturi gas mixer at the inlet manifold. Experiments have been conducted at various compression ratios (18, 17.5, 17 and 16) and under different loading conditions fixing the standard injection timing at 23° before top dead centre. At 100% load, the brake thermal efficiencies of the dual fuel mode are found to be 20.04%, 18.25%, 17.07% and 16.42% at compression ratios of 18, 17.5, 17 and 16, respectively, whereas at the same load, the diesel mode shows an efficiency of 27.76% at a compression ratio of 17.5. The maximum replacement of the precious fossil fuel is found to be 79.46%, 76.1%, 74% and 72% at compression ratios of 18, 17.5, 17 and 16, respectively at 100% load. For the dual fuel mode, on an average, there is a reduction in carbon monoxide as well as hydrocarbon emission by 26.22% and 41.97% when compression

A high voltage ratio and low ripple interleaved DC-DC converter for fuel cell applications.

Science.gov (United States)

Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

2012-01-01

This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters.

Indoor air quality scenario in India-An outline of household fuel combustion

Science.gov (United States)

Rohra, Himanshi; Taneja, Ajay

2016-03-01

Most of the research around the world has been on outdoor air pollution, but in India we have a more severe problem of Indoor Air Pollution (IAP). The foremost factor cited for is burning of fossil fuels for cooking. Among the 70% of the country's rural population, about 80% households rely on biomass fuel making India to top the list of countries with largest population lacking access to cleaner fuel for cooking. 4 million deaths and 5% disability-adjusted life-years is an upshot of exposure to IAP from unhealthy cooking making it globally the most critical environmental risk factor. India alone bears the highest burden (28% needless deaths) among developing countries. Moreover, about ¼ of ambient PM2.5 in the country comes from household cookfuels. These considerations have prompted the discussion of the present knowledge on the disastrous health effects of pollutants emitted by biomass combustion in India. Additionally, Particulate Matter as an indoor air pollutant is highlighted with main focus on its spatial temporal variation and some recent Indian studies are further explored. As there are no specific norms for IAP in India, urgent need has arisen for implementing the strategies to create public awareness. Moreover improvement in ventilation and modification in the pattern of fuel will also contribute to eradicate this national health issue.

The effect of nitrogen oxides in air on the performance of proton exchange membrane fuel cell

International Nuclear Information System (INIS)

Yang Daijun; Ma Jianxin; Xu Lin; Wu Minzhong; Wang Haijiang

2006-01-01

The effects of NO x on the performance of proton exchange membrane (PEM) fuel cell were investigated through the introduction of a mixture containing NO and NO 2 , in a ratio of 9:1, into the cathode stream of a single PEM fuel cell. The NO x concentrations used in the experiments were 1480 ppm, 140 ppm and 10 ppm, which cover a range of three orders. The experimental results obtained from the tests of durability, polarization, reversibility and electrochemical impedance spectroscopy (EIS) showed a detrimental effect of NO x on the cell performance. The electrochemical measurements results suggested that the impacts of NO x are mainly resulted from the superposition of the oxygen reduction reaction (ORR), NO and HNO 2 oxidation reactions, and the increased cathodic impedance. Complete recovery of the cell performance was reached after operating the cell with clean air and then purging with N 2 for hours

Influence of fuel ratios on auto combustion synthesis of barium ferrite ...

Indian Academy of Sciences (India)

Unknown

Influence of fuel ratios on auto combustion synthesis of barium ferrite nano particles. D BAHADUR*, S RAJAKUMAR and ANKIT KUMAR. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology,. Mumbai 400 076 e-mail: dhirenb@iitb.ac.in. Abstract. Single-domain barium ferrite nano ...

Hydrogen as automotive fuel

International Nuclear Information System (INIS)

Ambrosini, G.; Ciancia, A.; Pede, G.; Brighigna, M.

1993-01-01

Hydrogen fueled vehicles may just be the answer to the air pollution problem in highly polluted urban environments where the innovative vehicle's air pollution abatement characteristics would justify its high operating costs as compared with those of conventional automotive alternatives. This paper examines the feasibility of hydrogen as an automotive fuel by analyzing the following aspects: the chemical-physical properties of hydrogen in relation to its use in internal combustion engines; the modifications necessary to adapt internal combustion engines to hydrogen use; hydrogen fuel injection systems; current production technologies and commercialization status of hydrogen automotive fuels; energy efficiency ratings; environmental impacts; in-vehicle storage systems - involving the use of hydrides, high pressure systems and liquid hydrogen storage systems; performance in terms of pay-load ratio; autonomous operation; and operating costs. With reference to recent trial results being obtained in the USA, an assessment is also made of the feasibility of the use of methane-hydrogen mixtures as automotive fuels. The paper concludes with a review of progress being made by ENEA (the Italian Agency for New Technology, Energy and the Environment) in the development of fuel storage and electronic fuel injection systems for hydrogen powered vehicles

Commuters' exposure to particulate matter air pollution is affected by mode of transport, fuel type, and route.

Science.gov (United States)

Zuurbier, Moniek; Hoek, Gerard; Oldenwening, Marieke; Lenters, Virissa; Meliefste, Kees; van den Hazel, Peter; Brunekreef, Bert

2010-06-01

Commuters are exposed to high concentrations of air pollutants, but little quantitative information is currently available on differences in exposure between different modes of transport, routes, and fuel types. The aim of our study was to assess differences in commuters' exposure to traffic-related air pollution related to transport mode, route, and fuel type. We measured particle number counts (PNCs) and concentrations of PM2.5 (particulate matter bus passengers, we calculated that the inhaled air pollution doses were highest for cyclists. With the exception of PM10, we found that inhaled air pollution doses were lowest for electric bus passengers. Commuters' rush hour exposures were significantly influenced by mode of transport, route, and fuel type.

Perspective use of direct human blood as an energy source in air-breathing hybrid microfluidic fuel cells

Science.gov (United States)

Dector, A.; Escalona-Villalpando, R. A.; Dector, D.; Vallejo-Becerra, V.; Chávez-Ramírez, A. U.; Arriaga, L. G.; Ledesma-García, J.

2015-08-01

This work presents a flexible and light air-breathing hybrid microfluidic fuel cell (HμFC) operated under biological conditions. A mixture of glucose oxidase, glutaraldehyde, multi-walled carbon nanotubes and vulcan carbon (GOx/VC-MWCNT-GA) was used as the bioanode. Meanwhile, integrating an air-exposed electrode (Pt/C) as the cathode enabled direct oxygen delivery from air. The microfluidic fuel cell performance was evaluated using glucose obtained from three different sources as the fuel: 5 mM glucose in phosphate buffer, human serum and human blood. For the last fuel, an open circuit voltage and maximum power density of 0.52 V and 0.20 mW cm-2 (at 0.38 V) were obtained respectively; meanwhile the maximum current density was 1.1 mA cm-2. Furthermore, the stability of the device was measured in terms of recovery after several polarization curves, showing excellent results. Although this air-breathing HμFC requires technological improvements before being tested in a biomedical device, it represents the best performance to date for a microfluidic fuel cell using human blood as glucose source.

Alcohol Fuel in Passenger Car

Directory of Open Access Journals (Sweden)

Adam Polcar

2016-01-01

Full Text Available The present article studies the effects of combustion of high-percentage mixture of bioethanol and gasoline on the output parameters of a passenger car engine. The car engine has not been structurally modified for the combustion of fuels with higher ethanol content. The mixture used consisted of E85 summer blend and Natural 95 gasoline in a ratio of 50:50. The parameters monitored during the experiment included the air-fuel ratio in exhaust gasses, the power output and torque of the engine and also the specific energy consumption and efficiency of the engine. As is apparent from the results, E85+N95 (50:50 mixture combustion results in lean-burn (λ > 1 due to the presence of oxygen in bioethanol. The lean-burn led to a slight decrease in torque and power output of the engine. However, due to the positive physicochemical properties of bioethanol, the decrease has not been as significant as would normally be expected from the measured air-fuel ratio. These findings are further confirmed by the calculated energy required to produce 1 kWh of energy, and by the higher efficiency of the engine during the combustion of a 50% bioethanol mixture.

Numerical and experimental investigation of the effect of geometry on combustion characteristics of solid-fuel ramjet

Science.gov (United States)

Gong, Lunkun; Chen, Xiong; Musa, Omer; Yang, Haitao; Zhou, Changsheng

2017-12-01

Numerical and experimental investigation on the solid-fuel ramjet was carried out to study the effect of geometry on combustion characteristics. The two-dimensional axisymmetric program developed in the present study adopted finite rate chemistry and second-order moment turbulence-chemistry models, together with k-ω shear stress transport (SST) turbulence model. Experimental data were obtained by burning cylindrical polyethylene using a connected pipe facility. The simulation results show that a fuel-rich zone near the solid fuel surface and an air-rich zone in the core exist in the chamber, and the chemical reactions occur mainly in the interface of this two regions; The physical reasons for the effect of geometry on regression rate is the variation of turbulent viscosity due to the geometry change. Port-to-inlet diameter ratio is the main parameter influencing the turbulent viscosity, and a linear relationship between port-to-inlet diameter and regression rate were obtained. The air mass flow rate and air-fuel ratio are the main influencing factors on ramjet performances. Based on the simulation results, the correlations between geometry and air-fuel ratio were obtained, and the effect of geometry on ramjet performances was analyzed according to the correlation. Three-dimensional regression rate contour obtained experimentally indicates that the regression rate which shows axisymmetric distribution due to the symmetry structure increases sharply, followed by slow decrease in axial direction. The radiation heat transfer in recirculation zone cannot be ignored. Compared with the experimental results, the deviations of calculated average regression rate and characteristic velocity are about 5%. Concerning the effect of geometry on air-fuel ratio, the deviations between experimental and theoretical results are less than 10%.

Conclusions and recommendations. [for problems in energy situation, air transportation, and hydrogen fuel

Science.gov (United States)

1973-01-01

Conclusions and recommendations are presented for an analysis of the total energy situation; the effect of the energy problem on air transportation; and hydrogen fuel for aircraft. Properties and production costs of fuels, future prediction for energy and transportation, and economic aspects of hydrogen production are appended.

Spent fuel sabotage aerosol ratio program : FY 2004 test and data summary.

Energy Technology Data Exchange (ETDEWEB)

Brucher, Wenzel (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany); Koch, Wolfgang (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Pretzsch, Gunter Guido (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany); Loiseau, Olivier (Institut de Radioprotection et de Surete Nucleaire, France); Mo, Tin (U.S. Nuclear Regulatory Commission, Washington, DC); Billone, Michael C. (Argonne National Laboratory, Argonne, IL); Autrusson, Bruno A. (Institut de Radioprotection et de Surete Nucleaire, France); Young, F. I. (U.S. Nuclear Regulatory Commission, Washington, DC); Coats, Richard Lee; Burtseva, Tatiana (Argonne National Laboratory, Argonne, IL); Luna, Robert Earl; Dickey, Roy R.; Sorenson, Ken Bryce; Nolte, Oliver (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Thompson, Nancy Slater (U.S. Department of Energy, Washington, DC); Hibbs, Russell S. (U.S. Department of Energy, Washington, DC); Gregson, Michael Warren; Lange, Florentin (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany); Molecke, Martin Alan; Tsai, Han-Chung (Argonne National Laboratory, Argonne, IL)

2005-07-01

This multinational, multi-phase spent fuel sabotage test program is quantifying the aerosol particles produced when the products of a high energy density device (HEDD) interact with and explosively particulate test rodlets that contain pellets of either surrogate materials or actual spent fuel. This program has been underway for several years. This program provides data that are relevant to some sabotage scenarios in relation to spent fuel transport and storage casks, and associated risk assessments. The program also provides significant technical and political benefits in international cooperation. We are quantifying the Spent Fuel Ratio (SFR), the ratio of the aerosol particles released from HEDD-impacted actual spent fuel to the aerosol particles produced from surrogate materials, measured under closely matched test conditions, in a contained test chamber. In addition, we are measuring the amounts, nuclide content, size distribution of the released aerosol materials, and enhanced sorption of volatile fission product nuclides onto specific aerosol particle size fractions. These data are the input for follow-on modeling studies to quantify respirable hazards, associated radiological risk assessments, vulnerability assessments, and potential cask physical protection design modifications. This document includes an updated description of the test program and test components for all work and plans made, or revised, during FY 2004. It also serves as a program status report as of the end of FY 2004. All available test results, observations, and aerosol analyses plus interpretations--primarily for surrogate material Phase 2 tests, series 2/5A through 2/9B, using cerium oxide sintered ceramic pellets are included. Advanced plans and progress are described for upcoming tests with unirradiated, depleted uranium oxide and actual spent fuel test rodlets. This spent fuel sabotage--aerosol test program is coordinated with the international Working Group for Sabotage Concerns of

Spent fuel sabotage aerosol ratio program : FY 2004 test and data summary

International Nuclear Information System (INIS)

Brucher, Wenzel; Koch, Wolfgang; Pretzsch, Gunter Guido; Loiseau, Olivier; Mo, Tin; Billone, Michael C.; Autrusson, Bruno A.; Young, F. I.; Coats, Richard Lee; Burtseva, Tatiana; Luna, Robert Earl; Dickey, Roy R.; Sorenson, Ken Bryce; Nolte, Oliver; Thompson, Nancy Slater; Hibbs, Russell S.; Gregson, Michael Warren; Lange, Florentin; Molecke, Martin Alan; Tsai, Han-Chung

2005-01-01

This multinational, multi-phase spent fuel sabotage test program is quantifying the aerosol particles produced when the products of a high energy density device (HEDD) interact with and explosively particulate test rodlets that contain pellets of either surrogate materials or actual spent fuel. This program has been underway for several years. This program provides data that are relevant to some sabotage scenarios in relation to spent fuel transport and storage casks, and associated risk assessments. The program also provides significant technical and political benefits in international cooperation. We are quantifying the Spent Fuel Ratio (SFR), the ratio of the aerosol particles released from HEDD-impacted actual spent fuel to the aerosol particles produced from surrogate materials, measured under closely matched test conditions, in a contained test chamber. In addition, we are measuring the amounts, nuclide content, size distribution of the released aerosol materials, and enhanced sorption of volatile fission product nuclides onto specific aerosol particle size fractions. These data are the input for follow-on modeling studies to quantify respirable hazards, associated radiological risk assessments, vulnerability assessments, and potential cask physical protection design modifications. This document includes an updated description of the test program and test components for all work and plans made, or revised, during FY 2004. It also serves as a program status report as of the end of FY 2004. All available test results, observations, and aerosol analyses plus interpretations--primarily for surrogate material Phase 2 tests, series 2/5A through 2/9B, using cerium oxide sintered ceramic pellets are included. Advanced plans and progress are described for upcoming tests with unirradiated, depleted uranium oxide and actual spent fuel test rodlets. This spent fuel sabotage--aerosol test program is coordinated with the international Working Group for Sabotage Concerns of

Liftoff and blowoff of a diffusion flame between parallel streams of fuel and air

Energy Technology Data Exchange (ETDEWEB)

Fernandez-Tarrazo, Eduardo [I.N.T.A. Area de Propulsion-Edificio R02, Ctra. Ajalvir, km 4, 28850 Torrejon de Ardoz, Madrid (Spain); Vera, Marcos [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Linan, Amable [Departamento de Motopropulsion y Termofluidodinamica, Universidad Politecnica de Madrid, Pza. Cardenal Cisneros 3, 28040 Madrid (Spain)

2006-01-01

A numerical analysis is presented to describe the liftoff and blowoff of a diffusion flame in the mixing layer between two parallel streams of fuel (mainly methane diluted with nitrogen) and air emerging from porous walls. The analysis, which takes into account the effects of thermal expansion, assumes a one-step overall Arrhenius reaction, where the activation energy E is allowed to vary to reproduce the variations of the planar flame propagation velocity with the equivalence ratio. First, we describe the steady flame-front structure when stabilized close to the porous wall (attached flame regime). Then, we analyze the case where the flame front is located far away from the porous wall, at a distance x{sub f}' such that, upstream of the flame front, the mixing layer has a self-similar structure (lifted flame regime). For steady lifted flames, the results, given here in the case when the fuel and air streams are injected with the same velocity, relate U{sub f}'/S{sub L}, the front velocity (relative to the upstream flow) measured with the planar stoichiometric flame velocity, with the Damkohler number D{sub m}=({delta}{sub m}/{delta}{sub L}){sup 2}, based on the thickness, {delta}{sub m}, of the nonreacting mixing layer at the flame-front position and the laminar flame thickness, {delta}{sub L}. For large values of D{sub m}, the results, presented here for a wide range of dilutions of the fuel stream, provide values of the front propagation velocity that are in good agreement with previous experimental results, yielding well-defined conditions for blowoff. The calculated flame-front velocity can also be used to describe the transient flame-front dynamics after ignition by an external energy source.

Effect of Variable Compression Ratio on Performance of a Diesel Engine Fueled with Karanja Biodiesel and its Blends

Science.gov (United States)

Mishra, Rahul Kumar; soota, Tarun, Dr.; singh, Ranjeet

2017-08-01

Rapid exploration and lavish consumption of underground petroleum resources have led to the scarcity of underground fossil fuels moreover the toxic emissions from such fuels are pernicious which have increased the health hazards around the world. So the aim was to find an alternative fuel which would meet the requirements of petroleum or fossil fuels. Biodiesel is a clean, renewable and bio-degradable fuel having several advantages, one of the most important of which is being its eco-friendly and better knocking characteristics than diesel fuel. In this work the performance of Karanja oil was analyzed on a four stroke, single cylinder, water cooled, variable compression ratio diesel engine. The fuel used was 5% - 25% karanja oil methyl ester by volume in diesel. The results such obtained are compared with standard diesel fuel. Several properties i.e. Brake Thermal Efficiency, Brake Specific Fuel Consumptions, Exhaust Gas Temperature are determined at all operating conditions & at variable compression ratio 17 and 17.5.

Performance of cladding on MOX fuel with low 240Pu/239Pu ratio

International Nuclear Information System (INIS)

McCoy, K.; Blanpain, P.; Morris, R.

2015-01-01

The U.S. Department of Energy has decided to dispose of a portion of its surplus plutonium by reconstituting it into mixed oxide (MOX) fuel and irradiating it in commercial power reactors. As part of fuel qualification, four lead assemblies were manufactured and irradiated to a maximum fuel rod average burnup of 47.3 MWd/kg heavy metal. This was the world's first commercial irradiation of MOX fuel with a 240 Pu/ 239 Pu ratio less than 0.10. Five fuel rods with varying burnups and plutonium contents were selected from one of the assemblies and shipped to Oak Ridge National Laboratory for hot cell examination. This paper discusses the results of those examinations with emphasis on cladding performance. Exams relevant to the cladding included visual and eddy current exams, profilometry, microscopy, hydrogen analysis, gallium analysis, and mechanical testing. There was no discernible effect of the type of MOX fuel on the performance of the cladding. (authors)

Improvement of performance in low temperature solid oxide fuel cells operated on ethanol and air mixtures using Cu-ZnO-Al2O3 catalyst layer

Science.gov (United States)

Morales, M.; Espiell, F.; Segarra, M.

2015-10-01

Anode-supported single-chamber solid oxide fuel cells with and without Cu-ZnO-Al2O3 catalyst layers deposited on the anode support have been operated on ethanol and air mixtures. The cells consist of gadolinia-doped ceria electrolyte, Ni-doped ceria anode, and La0.6Sr0.4CoO3-δ-doped ceria cathode. Catalyst layers with different Cu-ZnO-Al2O3 ratios are deposited and sintered at several temperatures. Since the performance of single-chamber fuel cells strongly depends on catalytic properties of electrodes for partial oxidation of ethanol, the cells are electrochemically characterized as a function of the temperature, ethanol-air molar ratio and gas flow rate. In addition, catalytic activities of supported anode, catalytic layer-supported anode and cathode for partial oxidation of ethanol are analysed. Afterwards, the effect of composition and sintering temperature of catalyst layer on the cell performance are determined. The results indicate that the cell performance can be significantly enhanced using catalyst layers of 30:35:35 and 40:30:30 wt.% Cu-ZnO-Al2O3 sintered at 1100 °C, achieving power densities above 50 mW cm-2 under 0.45 ethanol-air ratio at temperatures as low as 450 °C. After testing for 15 h, all cells present a gradual loss of power density, without carbon deposition, which is mainly attributed to the partial re-oxidation of Ni at the anode.

Effect of Collector Aspect Ratio on the Thermal Performance of Wavy Finned Absorber Solar Air Heater

OpenAIRE

Abhishek Priyam; Prabha Chand

2016-01-01

A theoretical investigation on the effect of collector aspect ratio on the thermal performance of wavy finned absorber solar air heaters has been performed. For the constant collector area, the various performance parameters have been calculated for plane and wavy finned solar air heaters. It has been found that the performance of wavy finned solar air heater improved with the increase in the collector aspect ratio. The performance of wavy finned solar air heater has been found 30 percent hig...

Experimental study on two-stage air supply downdraft gasifier and dual fuel engine system

Energy Technology Data Exchange (ETDEWEB)

Nhuchhen, Daya Ram; Salam, P.A. [Asian Institute of Technology, Energy Field of Study, School of Environment Resource and Development, P. O. Box 4, Klong Luang, Pathumthani (Thailand)

2012-06-15

Biomass is a widely used renewable energy resource with net balanced carbon dioxide absorptions and emissions. An inefficient use of solid biomass in combustion process emits more gaseous pollutants, increasing the pollution level. Biomass gasification is one of the techniques to support efficient use of biomass. Multistage gasification is a method of gasification to improve quality of the producer gas in which two separate reactors are designed for separating gasification reactions. This study presents experimental results of gasification using Eucalyptus wood in a single long cylindrical reactor with two air supply ports, i.e., primary and secondary. The effect of different air supply rates on the heating values of the producer gas was studied. Optimum primary and secondary air supply rate of 100 and 80 l/min at equivalence ratio of 0.38 was observed with producer gas lower heating value of 4.72 MJ Nm{sup -3}. The performance of a diesel engine in the dual fuel mode was also evaluated. The overall gasifier engine system efficiency was 13.86 % at an electrical load of 10.54 kW{sub e} with specific energy consumption of 16.22 MJ kWh{sup -1}. The heat recovery system was designed and tested to recover heat from producer gas in the form of hot water. (orig.)

Intelligent Engine Systems: Alternate Fuels Evaluation

Science.gov (United States)

Ballal, Dilip

2008-01-01

The performance and gaseous emissions were measured for a well-stirred reactor operating under lean conditions for two fuels: JP8 and a synthetic Fisher-Tropsch fuel over a range of equivalence ratios from 0.6 down to the lean blowout. The lean blowout characteristics were determined in LBO experiments at loading parameter values from 0.7 to 1.4. The lean blowout characteristics were then explored under higher loading conditions by simulating higher altitude operation with the use of nitrogen as a dilution gas for the air stream. The experiments showed that: (1) The lean blowout characteristics for the two fuels were close under both low loading and high loading conditions. (2) The combustion temperatures and observed combustion efficiencies were similar for the two fuels. (3) The gaseous emissions were similar for the two fuels and the differences in the H2O and CO2 emissions appear to be directly relatable to the C/H ratio for the fuels.

Experience of air transport of nuclear fuel material in Japan

International Nuclear Information System (INIS)

Yamashita, T.; Toguri, D.; Kawasaki, M.

2004-01-01

Certified Reference Materials (hereafter called as to CRMs), which are indispensable for Quality Assurance and Material Accountability in nuclear fuel plants, are being provided by overseas suppliers to Japanese nuclear entities as Type A package (non-fissile) through air transport. However, after the criticality accident at JCO in Japan, special law defining nuclear disaster countermeasures (hereafter called as to the LAW) has been newly enforced in June 2000. Thereafter, nuclear fuel materials must meet not only to the existing transport regulations but also to the LAW for its transport

Impact of aspect ratio and solar heating on street canyon air temperature

International Nuclear Information System (INIS)

Memon, R.A.; Lal, K.

2011-01-01

The results obtained from RNG (Re-Normalization Group) version of k-and turbulence model are reported in this study. The model is adopted to elucidate the impact of different building aspect ratios (i.e., ratio of building-height-to-street-canyon-width) and solar heating on temperatures in street canyon. The validation of Navier-Stokes and energy an sport equations showed that the model prediction for air-temperature and ambient wind provides reasonable accuracy. The model was applied on AR (Aspect Ratios) one to eight and surface temperature difference (delta and theta/sub s-a/)) of 2 -8. Notably, air-temperatures were higher in high AR street canyons in particular on the leeward side of the street canyon. Further investigation showed that the difference between the air-temperature 'high and low AR street canyons (AR) was positive and high with higher delta and theta/sub s-a/) conversely, the AR become negative and low gradually with lower values of delta and theta(/sub s-a/). These results could be very beneficial for the city and regional planners, civil engineers Id HVAC experts who design street canyons and strive for human thermal comfort with minimum possible energy requirements. (author)

Impact of Aspect Ratio and Solar Heating on Street Conyn Air Temperature

Directory of Open Access Journals (Sweden)

Rizwan Ahmed Memon

2011-01-01

Full Text Available The results obtained from RNG (Re-Normalization Group version of k-? turbulence model are reported in this study. The model is adopted to elucidate the impact of different building aspect ratios (i.e., ratio of building-height-to-street-canyon-width and solar heating on temperatures in street canyon. The validation of Navier-Stokes and energy transport equations showed that the model prediction for air-temperature and ambient wind provides reasonable accuracy. The model was applied on AR (Aspect Ratios one to eight and surface temperature difference (??s-a of 2 -8. Notably, air-temperatures were higher in high AR street canyons in particular on the leeward side of the street canyon. Further investigation showed that the difference between the air-temperature of high and low AR street canyons ( AR was positive and high with higher ??s-a. Conversely, the AR become negative and low gradually with lower values of ??s-a. These results could be very beneficial for the city and regional planners, civil engineers and HVAC experts who design street canyons and strive for human thermal comfort with minimum possible energy requirements.

Seeking effective dyes for a mediated glucose-air alkaline battery/fuel cell

Science.gov (United States)

Eustis, Ross; Tsang, Tsz Ming; Yang, Brigham; Scott, Daniel; Liaw, Bor Yann

2014-02-01

A significant level of power generation from an abiotic, air breathing, mediated reducing sugar-air alkaline battery/fuel cell has been achieved in our laboratories at room temperature without complicated catalysis or membrane separation in the reaction chamber. Our prior studies suggested that mass transport limitation by the mediator is a limiting factor in power generation. New and effective mediators were sought here to improve charge transfer and power density. Forty-five redox dyes were studied to identify if any can facilitate mass transport in alkaline electrolyte solution; namely, by increasing the solubility and mobility of the dye, and the valence charge carried per molecule. Indigo dyes were studied more closely to understand the complexity involved in mass transport. The viability of water-miscible co-solvents was also explored to understand their effect on solubility and mass transport of the dyes. Using a 2.0 mL solution, 20% methanol by volume, with 100 mM indigo carmine, 1.0 M glucose and 2.5 M sodium hydroxide, the glucose-air alkaline battery/fuel cell attained 8 mA cm-2 at short-circuit and 800 μW cm-2 at the maximum power point. This work shall aid future optimization of mediated charge transfer mechanism in batteries or fuel cells.

Air conditioning facilities in a fuel reprocessing plant

International Nuclear Information System (INIS)

Kawasaki, Michitaka; Oka, Tsutomu

1987-01-01

Reprocessing plants are the facilities for separating the plutonium produced by nuclear reaction and unconsumed remaining uranium from fission products in the spent fuel taken out of nuclear reactors and recovering them. The fuel reprocessing procedure is outlined. In order to ensure safety in handling radioactive substances, triple confinement using vessels, concrete cells and buildings is carried out in addition to the prevention of criticality and radiation shielding, and stainless steel linings and drip trays are installed as occasion demands. The ventilation system in a reprocessing plant is roughly divided into three systems, that is, tower and tank ventilation system to deal with offgas, cell ventilation system for the cells in which main towers and tanks are installed, and building ventilation system. Air pressure becomes higher from tower and tank system to building system. In a reprocessing plant, the areas in a building are classified according to dose rate. The building ventilation system deals with green and amber areas, and the cell ventilation system deals with red area. These three ventilation systems are explained. Radiation monitors are installed to monitor the radiation dose rate and air contamination in working places. The maintenance and checkup of ventilation systems are important. (Kako, I.)

Environmental impact of alternative fuel on Tehran air pollution

International Nuclear Information System (INIS)

Ebtekar, T.

1995-01-01

Seventy percent of the air pollution in the city of Tehran stems from mobile sources, and in comparison with other major cities of the world, Iran's capital experiences one of the most polluted metropolitan areas. There exists a surplus of liquid petroleum gas (LPG) in the Persian Gulf and Iranian market, in addition, Iran possesses the second largest reservoir of natural gas in the world. These alternative energy resources create a favorable potential fuel for city of Tehran. Experiments carried out in Tehran indicate that in converting the taxis from gasoline to a dual fuel (LPG/gasoline) car or to a dual fuel natural gas vehicle (NGV) reduce all major pollutants (CO, HC, NOX, Pb) substantially. Following the author's recommendation, the number of LPG dispensing units in gas stations are increasing and the number of dual fuel taxis amount to several thousands in the metropolitan area. The conversion of diesel buses in the Tehran Public Transportation Corporation to natural gas (NGV) has been recommended by the author and vast experimental works are underway at the present time

A parametric study of the microwave plasma-assisted combustion of premixed ethylene/air mixtures

Science.gov (United States)

Fuh, Che A.; Wu, Wei; Wang, Chuji

2017-11-01

A parametric study of microwave argon plasma assisted combustion (PAC) of premixed ethylene/air mixtures was carried out using visual imaging, optical emission spectroscopy and cavity ringdown spectroscopy as diagnostic tools. The parameters investigated included the plasma feed gas flow rate, the plasma power, the fuel equivalence ratio and the total flow rate of the fuel/air mixture. The combustion enhancement effects were characterized by the minimum ignition power, the flame length and the fuel efficiency of the combustor. It was found that: (1) increasing the plasma feed gas flow rate resulted in a decrease in the flame length, an increase in the minimum ignition power for near stoichiometric fuel equivalence ratios and a corresponding decrease in the minimum ignition power for ultra-lean and rich fuel equivalence ratios; (2) at a constant plasma power, increasing the total flow rate of the ethylene/air mixture from 1.0 slm to 1.5 slm resulted in an increase in the flame length and a reduction in the fuel efficiency; (3) increasing the plasma power resulted in a slight increase in flame length as well as improved fuel efficiency with fewer C2(d) and CH(A) radicals present downstream of the flame; (4) increasing the fuel equivalence ratio caused an increase in flame length but at a reduced fuel efficiency when plasma power was kept constant; and (5) the ground state OH(X) number density was on the order of 1015 molecules/cm3 and was observed to drop downstream along the propagation axis of the flame at all parameters investigated. Results suggest that each of the parameters independently influences the PAC processes.

Performance of artificially defected LWR fuel rods in an unlimited air dry storage atmosphere

International Nuclear Information System (INIS)

Einziger, R.E.; Knecht, R.L.; Cantley, D.A.; Cook, J.A.

1983-09-01

Thus far the tests are inconclusive as to whether breached LWR fuel can be stored at 230 0 C for long periods of time in air without fuel oxidation and dispersion. There is every indication, as expected, that there is no oxidation problem in an inert atmosphere. Only one of four defects exposed to unlimited air gave any indication of fuel oxidation. It has been suggested that this might be an incubation effect and continued operation would result in oxidation occurring at all four defects. As yet the destructive examination of the BWR rod has not been completed, so it is not possible to determine if cladding splitting was due to an anomoly in this test rod or something that can be expected in LWR rods in general. Thus far there is no indication of respirable particle dispersal even if fuel oxidation does occur

Power plant fuel switching and air quality in a tropical, forested environment

Science.gov (United States)

Medeiros, Adan S. S.; Calderaro, Gisele; Guimarães, Patricia C.; Magalhaes, Mateus R.; Morais, Marcos V. B.; Rafee, Sameh A. A.; Ribeiro, Igor O.; Andreoli, Rita V.; Martins, Jorge A.; Martins, Leila D.; Martin, Scot T.; Souza, Rodrigo A. F.

2017-07-01

How a changing energy matrix for electricity production affects air quality is considered for an urban region in a tropical, forested environment. Manaus, the largest city in the central Amazon Basin of Brazil, is in the process of changing its energy matrix for electricity production from fuel oil and diesel to natural gas over an approximately 10-year period, with a minor contribution by hydropower. Three scenarios of urban air quality, specifically afternoon ozone concentrations, were simulated using the Weather Research and Forecasting (WRF-Chem) model. The first scenario used fuel oil and diesel for electricity production, which was the reality in 2008. The second scenario was based on the fuel mix from 2014, the most current year for which data were available. The third scenario considered nearly complete use of natural gas for electricity production, which is the anticipated future, possibly for 2018. For each case, inventories of anthropogenic emissions were based on electricity generation, refinery operations, and transportation. Transportation and refinery operations were held constant across the three scenarios to focus on effects of power plant fuel switching in a tropical context. The simulated NOx and CO emissions for the urban region decrease by 89 and 55 %, respectively, after the complete change in the energy matrix. The results of the simulations indicate that a change to natural gas significantly decreases maximum afternoon ozone concentrations over the population center, reducing ozone by > 70 % for the most polluted days. The sensitivity of ozone concentrations to the fuel switchover is consistent with a NOx-limited regime, as expected for a tropical forest having high emissions of biogenic volatile organic compounds, high water vapor concentrations, and abundant solar radiation. There are key differences in a shifting energy matrix in a tropical, forested environment compared to other world environments. Policies favoring the burning of

Power plant fuel switching and air quality in a tropical, forested environment

Directory of Open Access Journals (Sweden)

A. S. S. Medeiros

2017-07-01

Full Text Available How a changing energy matrix for electricity production affects air quality is considered for an urban region in a tropical, forested environment. Manaus, the largest city in the central Amazon Basin of Brazil, is in the process of changing its energy matrix for electricity production from fuel oil and diesel to natural gas over an approximately 10-year period, with a minor contribution by hydropower. Three scenarios of urban air quality, specifically afternoon ozone concentrations, were simulated using the Weather Research and Forecasting (WRF-Chem model. The first scenario used fuel oil and diesel for electricity production, which was the reality in 2008. The second scenario was based on the fuel mix from 2014, the most current year for which data were available. The third scenario considered nearly complete use of natural gas for electricity production, which is the anticipated future, possibly for 2018. For each case, inventories of anthropogenic emissions were based on electricity generation, refinery operations, and transportation. Transportation and refinery operations were held constant across the three scenarios to focus on effects of power plant fuel switching in a tropical context. The simulated NOx and CO emissions for the urban region decrease by 89 and 55 %, respectively, after the complete change in the energy matrix. The results of the simulations indicate that a change to natural gas significantly decreases maximum afternoon ozone concentrations over the population center, reducing ozone by > 70 % for the most polluted days. The sensitivity of ozone concentrations to the fuel switchover is consistent with a NOx-limited regime, as expected for a tropical forest having high emissions of biogenic volatile organic compounds, high water vapor concentrations, and abundant solar radiation. There are key differences in a shifting energy matrix in a tropical, forested environment compared to other world environments. Policies

Effects of fractal grid on emissions in burner combustion by using fuel-water-air premix injector derived from biodiesel crude palm oil (CPO base

Directory of Open Access Journals (Sweden)

Suardi Mirnah

2017-01-01

Full Text Available The alternative fuel is attracted good attention from worldwide especially for renewable and prevention energy such as biodiesel. Biodiesel is one of the hydrocarbon fuels and it has potential for external combustion. As one of the different solutions to these problems, rapid mixing of biodiesel-water-air technique is one of the most significant approaches to improve the combustion and reduce the emissions. The gas emission can be reduced by two methods. First is by improving an injector with fractal and the other is by using a biodiesel-water mixture as an alternative fuel. Mixing of water with fuel in the combustion process is a low cost and effective way. This research used biodiesel Crude Palm Oil (CPO as fuels in which blended with diesel. This study investigated the effects of water content and equivalence ratio on emissions with the rapid mixing injector. Fuels used are diesel, CPO5, CPO10 and CPO15 and the exhausts gaseous tested are CO, CO2, HC and NOX. The gas emissions processes are tested by using the gas analyzer. In this research, water premix of percentage up to 15vol% and blending biodiesel ratio was varied from 5vom% - 15vol%. The result shows that increasing of water content will effected decrement of CO, CO2 and HC emissions but increasing the NOX emissions.

Air pollution from motor vehicle emissions

International Nuclear Information System (INIS)

Petrushevska, Ljubica

1996-01-01

This paper presents some aspects of air pollution from motor vehicle emissions as: characteristic primary and secondary pollutants, dependence of the motor vehicle emission from the engine type; the relationship of typical engine emission and performance to air-fuel ratio, transport of pollutants from mobile sources of emissions, as well as some world experiences in the control approaches for exhaust emissions. (author)

A study on the amount of pilot injection and its effects on rich and lean boundaries of the premixed CNG/air mixture for a CNG/diesel dual-fuel engine

Energy Technology Data Exchange (ETDEWEB)

Zhiqiang Lin; Wanhua Su [Tianjin University (China). State Key Laboratory of Engines

2003-07-01

A sequential port injection, lean-burn, fully electronically-controlled compressed natural gas (CNG)/diesel dual-fuel engine has been developed based on a turbo-charged and inter-cooled direct injection (D.I.) diesel engine. During the optimisation of engine overall performance, the effects of pilot diesel and premixed CNG/air mixture equivalence ratio on emissions (CO, HC, NO{sub x}, soot), knocking, misfire and fuel economy are studied. The rich and lean boundaries of the premixed CNG/air mixture versus engine load are also provided, considering the acceptable values of NO{sub x} and THC emissions, respectively. It is interesting to find that there is a critical amount of pilot diesel for each load and speed point, which proved to be the optimum amount of pilot fuel. Any decrease in the amount of pilot diesel from this optimum amount results in an increase of NO{sub x} emissions, because the premixed CNG/air mixture must be made richer, otherwise THC emissions would increase. However, the soot emissions remain almost unchanged at a very low level. (author)

α-MnO2 Nanowires/Graphene Composites with High Electrocatalytic Activity for Mg-Air Fuel Cell

International Nuclear Information System (INIS)

Jiang, Min; He, Hao; Huang, Chen; Liu, Bo; Yi, Wen-Jun; Chao, Zi-Sheng

2016-01-01

Highlights: • α-MnO 2 NWs/graphene was synthesized and studied in Mg-air fuel cell. • The performance of α-MnO 2 NWs/graphene is close to the Pt/C. • The ORR mechanism involves a one-step, quasi-4-electron pathway. • A large area (5 cm*5 cm) cathode was prepared and tested in a full cell. - Abstract: This paper reports the preparation of α-MnO 2 NWs/graphene composites as the cathode catalyst for magnesium-air fuel cell and its excellent electrochemistry performance. The composites are synthesized by self-assembly of α-MnO 2 nan α-MnO 2 NWs/graphene was synthesized and studied in Mg-air fuel cell. α-MnO 2 NWs/graphene was synthesized and studied in Mg-air fuel cell. owires (NWs) on the surface of graphene via a simple hydrothermal method. The α-MnO 2 NWs/graphene composites showed a higher electrochemical activity than the commercial MnO 2 . The oxygen reduction peak of the α-MnO 2 NWs/graphene composites catalyst is tested in a 0.1 M KOH solution at −0.252 V, which is more positive than the commercial MnO 2 (−0.287 V). The ORR limit current density for 28% α-MnO2 NWs/graphene composite is approximately 2.74 mA/cm 2 , which is similar to that of the 20% Pt/C(2.79 mA/cm 2 ) in the same conditions. Based on the Koutecky–Levich plot, the ORR mechanism of the composite involves a one-step, quasi-4-electron pathway. In addition, magnesium-air fuel cell with α-MnO 2 NWs/graphene as catalyst possesses higher current density (140 mA/cm 2 ) and power density (96 mW/cm 2 ) compared to the commercial MnO 2 . This study proves that the cost-effective α-MnO 2 NWs/graphene with higher power generation ability make it possible for the substitute of the noble metals catalyst in the Mg-air fuel cell.

Effects of ashes in solid fuels on fuel particle charging during combustion in an air stream

Energy Technology Data Exchange (ETDEWEB)

Zakharov, A.G.; Fialkov, B.S.; Mel' nichuk, A.Yu.; Khvan, L.A.

1982-09-01

Black coal from the Karaganda basin is mixed with sodium chloride and graphite. Coal characteristics are given in a table (density, ashes, content of silica, aluminium oxides, iron oxides, calcium oxides, potassium oxides and magnesium oxides). Effects of ash fluctuations on electric potential of fuel particles during combustion are analyzed. Analyses show that with increasing ash content electric potential of fuel particles decreases and reaches the minimum when ash content ranges from 70 to 80 %. Particles with electric potential are generated during chemical processes between carbon and oxygen when coal is burned in an air stream. (5 refs.) (In Russian)

Analysis of cyclic variations of liquid fuel-air mixing processes in a realistic DISI IC-engine using Large Eddy Simulation

International Nuclear Information System (INIS)

Goryntsev, D.; Sadiki, A.; Klein, M.; Janicka, J.

2010-01-01

Direct injection spark ignition (DISI) engines have a large potential to reduce emissions and specific fuel consumption. One of the most important problem in the design of DISI engines is the cycle-to-cycle variations of the flow, mixing and combustion processes. The Large Eddy Simulation (LES) based analysis is used to characterize the cycle-to-cycle fluctuations of the flow field as well as the mixture preparation in a realistic four-stroke internal combustion engine with variable charge motion system. Based on the analysis of cycle-to-cycle velocity fluctuations of in-cylinder flow, the impact of various fuel spray boundary conditions on injection processes and mixture preparation is pointed out. The joint effect of both cycle-to-cycle velocity fluctuations and variable spray boundary conditions is discussed in terms of mean and standard deviation of relative air-fuel ratio, velocity and mass fraction. Finally a qualitative analysis of the intensity of cyclic fluctuations below the spark plug is provided.

Optimization of suitable ethanol blend ratio for motorcycle engine using response surface method.

Science.gov (United States)

Chen, Yu-Liang; Chen, Suming; Tsai, Jin-Ming; Tsai, Chao-Yin; Fang, Hsin-Hsiung; Yang, I-Chang; Liu, Sen-Yuan

2012-01-01

In view of energy shortage and air pollution, ethanol-gasoline blended fuel used for motorcycle engine was studied in this work. The emissions of carbon monoxide (CO), nitrogen oxides (NO(X)) and engine performance of a 125 cc four-stroke motorcycle engine with original carburetor using ethanol-gasoline fuels were investigated. The model of three-variable Box Behnken design (BBD) was used for experimental design, the ethanol blend ratios were prepared at 0, 10, 20 vol%; the speeds of motorcycle were selected as 30, 45, 60 km/h; and the throttle positions were set at 30, 60, 90 %. Both engine performance and air pollutant emissions were then analyzed by response surface method (RSM) to yield optimum operation parameters for tolerable pollutant emissions and maximum engine performance. The RSM optimization analysis indicated that the most suitable ethanol-gasoline blended ratio was found at the range of 3.92-4.12 vol% to yield a comparable fuel conversion efficiency, while considerable reductions of exhaust pollutant emissions of CO (-29 %) and NO(X) (-12 %) when compared to pure gasoline fuel. This study demonstrated low ethanol-gasoline blended fuels could be used in motorcycle carburetor engines without any modification to keep engine power while reducing exhaust pollutants.

Sulfur isotope ratios and the origins of the aerosols and cloud droplets in California stratus

International Nuclear Information System (INIS)

Ludwig, F.L.

1976-01-01

Marine aerosols often have sulfur-to-chloride ratios greater than that found in seawater. Sulfur isotope ratios ( 34 S/ 32 S) were measured in aerosol and cloud droplet samples collected in the San Francisco Bay Area in an attempt to understand the processes that produce the observed sulfur-to-chloride ratios. Seawater sulfur usually has very high sulfur isotope ratios: fossil fuel sulfur tends to have smaller isotope ratios and sulfur of bacteriogenic origin still smaller. Samples collected in unpolluted marine air over the hills south of San Francisco had sulfur ratios that were significantly lower than the values for samples collected in nearby areas that were subject to urban pollution. The highest sulfur isotope ratios were found in the offshore seawater. The results suggest bacteriogenic origins, of the marine air sulfur aerosol material. The low isotope ratios in the marine air cannot be explained as a mixture of seawater sulfur and pollutant sulfur, because both tend to have higher isotope ratios. (Auth.)

Dry air oxidation kinetics of K-Basin spent nuclear fuel

International Nuclear Information System (INIS)

Abrefah, J.; Buchanan, H.C.; Gerry, W.M.; Gray, W.J.; Marschman, S.C.

1998-06-01

The safety and process analyses of the proposed Integrated Process Strategy (IPS) to move the N-Reactor spent nuclear fuel (SNF) stored at K-Basin to an interim storage facility require information about the oxidation behavior of the metallic uranium. Limited experiments have been performed on the oxidation reaction of SNF samples taken from an N-Reactor outer fuel element in various atmospheres. This report discusses studies on the oxidation behavior of SNF using two independent experimental systems: (1) a tube furnace with a flowing gas mixture of 2% oxygen/98% argon; and (2) a thermogravimetric system for dry air oxidation

Store for burnt-up fuel elements of nuclear reactors

International Nuclear Information System (INIS)

Kumpf, H.

1981-01-01

Burnt-up fuel elements of nuclear reactors have to be cooled during storage. For this reason the boxes which surround the fuel elements can have cooling air flowing round them in natural flow. This air is taken through the walls of a storage building through zones of parallel pipes, whose diameter and spacing are in the ratio of 1 : 0.5 to 1 : 2. The pipes have dust filters. Prefilters with fan drive are situated in parallel with the inlet pipe zones. (orig.) [de

Impacts of Particulate Pollution from Fossil Fuel and Biomass Burnings on the Air Quality and Human Health in Southeast Asia

Science.gov (United States)

Lee, H. H.; Iraqui, O.; Gu, Y.; Yim, S. H. L.; Wang, C.

2017-12-01

Severe haze events in Southeast Asia have attracted the attention of governments and the general public in recent years, due to their impact on local economies, air quality and public health. Widespread biomass burning activities are a major source of severe haze events in Southeast Asia. On the other hand, particulate pollutants from human activities other than biomass burning also play an important role in degrading air quality in Southeast Asia. These pollutants can be locally produced or brought in from neighboring regions by long-range transport. A better understanding of the respective contributions of fossil fuel and biomass burning aerosols to air quality degradation becomes an urgent task in forming effective air pollution mitigation policies in Southeast Asia. In this study, to examine and quantify the contributions of fossil fuel and biomass burning aerosols to air quality and visibility degradation over Southeast Asia, we conducted three numerical simulations using the Weather Research and Forecasting (WRF) model coupled with a chemistry component (WRF-Chem). These simulations were driven by different aerosol emissions from: (a) fossil fuel burning only, (b) biomass burning only, and (c) both fossil fuel and biomass burning. By comparing the simulation results, we examined the corresponding impacts of fossil fuel and biomass burning emissions, separately and combined, on the air quality and visibility of the region. The results also showed that the major contributors to low visibility days (LVDs) among 50 ASEAN cities are fossil fuel burning aerosols (59%), while biomass burning aerosols provided an additional 13% of LVDs in Southeast Asia. In addition, the number of premature mortalities among ASEAN cities has increased from 4110 in 2002 to 6540 in 2008, caused primarily by fossil fuel burning aerosols. This study suggests that reductions in both fossil fuel and biomass burning emissions are necessary to improve the air quality in Southeast Asia.

Exposures to jet fuel and benzene during aircraft fuel tank repair in the U.S. Air Force.

Science.gov (United States)

Carlton, G N; Smith, L B

2000-06-01

Jet fuel and benzene vapor exposures were measured during aircraft fuel tank entry and repair at twelve U.S. Air Force bases. Breathing zone samples were collected on the fuel workers who performed the repair. In addition, instantaneous samples were taken at various points during the procedures with SUMMA canisters and subsequent analysis by mass spectrometry. The highest eight-hour time-weighted average (TWA) fuel exposure found was 1304 mg/m3; the highest 15-minute short-term exposure was 10,295 mg/m3. The results indicate workers who repair fuel tanks containing explosion suppression foam have a significantly higher exposure to jet fuel as compared to workers who repair tanks without foam (p fuel, absorbed by the foam, to volatilize during the foam removal process. Fuel tanks that allow flow-through ventilation during repair resulted in lower exposures compared to those tanks that have only one access port and, as a result, cannot be ventilated efficiently. The instantaneous sampling results confirm that benzene exposures occur during fuel tank repair; levels up to 49.1 mg/m3 were found inside the tanks during the repairs. As with jet fuel, these elevated benzene concentrations were more likely to occur in foamed tanks. The high temperatures associated with fuel tank repair, along with the requirement to wear vapor-permeable cotton coveralls for fire reasons, could result in an increase in the benzene body burden of tank entrants.

Atmospheric ammonia mixing ratios at an open-air cattle feeding facility.

Science.gov (United States)

Hiranuma, Naruki; Brooks, Sarah D; Thornton, Daniel C O; Auvermann, Brent W

2010-02-01

Mixing ratios of total and gaseous ammonia were measured at an open-air cattle feeding facility in the Texas Panhandle in the summers of 2007 and 2008. Samples were collected at the nominally upwind and downwind edges of the facility. In 2008, a series of far-field samples was also collected 3.5 km north of the facility. Ammonium concentrations were determined by two complementary laboratory methods, a novel application of visible spectrophotometry and standard ion chromatography (IC). Results of the two techniques agreed very well, and spectrophotometry is faster, easier, and cheaper than chromatography. Ammonia mixing ratios measured at the immediate downwind site were drastically higher (approximately 2900 parts per billion by volume [ppbv]) than thos measured at the upwind site (open-air animal feeding operations, especially under the hot and dry conditions present during these measurements.

Analysis on burnup step effect for evaluating reactor criticality and fuel breeding ratio

International Nuclear Information System (INIS)

Saputra, Geby; Purnama, Aditya Rizki; Permana, Sidik; Suzuki, Mitsutoshi

2014-01-01

Criticality condition of the reactors is one of the important factors for evaluating reactor operation and nuclear fuel breeding ratio is another factor to show nuclear fuel sustainability. This study analyzes the effect of burnup steps and cycle operation step for evaluating the criticality condition of the reactor as well as the performance of nuclear fuel breeding or breeding ratio (BR). Burnup step is performed based on a day step analysis which is varied from 10 days up to 800 days and for cycle operation from 1 cycle up to 8 cycles reactor operations. In addition, calculation efficiency based on the variation of computer processors to run the analysis in term of time (time efficiency in the calculation) have been also investigated. Optimization method for reactor design analysis which is used a large fast breeder reactor type as a reference case was performed by adopting an established reactor design code of JOINT-FR. The results show a criticality condition becomes higher for smaller burnup step (day) and for breeding ratio becomes less for smaller burnup step (day). Some nuclides contribute to make better criticality when smaller burnup step due to individul nuclide half-live. Calculation time for different burnup step shows a correlation with the time consuming requirement for more details step calculation, although the consuming time is not directly equivalent with the how many time the burnup time step is divided

Impact of partial fuel switch on household air pollutants in sub-Sahara Africa

International Nuclear Information System (INIS)

Tumwesige, Vianney; Okello, Gabriel; Semple, Sean; Smith, Jo

2017-01-01

Over 700 million people in Sub-Saharan Africa depend on solid biomass fuel and use simple cookstoves in poorly ventilated kitchens, which results in high indoor concentrations of household air pollutants. Switching from biomass to biogas as a cooking fuel can reduce airborne emissions of fine particulate matter (PM 2.5 ) and carbon monoxide (CO), but households often only partially convert to biogas, continuing to use solid biomass fuels for part of their daily cooking needs. There is little evidence of the benefits of partial switching to biogas. This study monitored real-time PM 2.5 and CO concentrations in 35 households in Cameroon and Uganda where biogas and firewood (or charcoal) were used. The 24 h mean PM 2.5 concentrations in households that used: (1) firewood and charcoal; (2) both firewood (mean 54% cooking time) and biogas (mean 46% cooking time); and (3) only biogas, were 449 μg m −3 , 173 μg m −3 and 18 μg m −3 respectively. The corresponding 24 h mean CO concentrations were 14.2 ppm, 2.7 ppm and 0.5 ppm. Concentrations of both PM 2.5 and CO were high and exceeded the World Health Organisation guidelines when firewood and charcoal were used. Partially switching to biogas reduced CO exposure to below the World Health Organisation guidelines, but PM 2.5 concentrations were only below the 24 h recommended limits when households fully converted to biogas fuel. These results indicate that partial switching from solid fuels to biogas is not sufficient and continues to produce concentrations of household air pollution that are likely to harm the health of those exposed. Programmes introducing biogas should aim to ensure that household energy needs can be fully achieved using biogas with no requirement to continue using solid fuels. - Highlights: • Air pollution exceeds WHO limits in African households using solid biomass fuels. • A partial switch to biogas reduced CO concentrations to below the WHO limit. • Particulates only fall to

Oxy-fuel combustion of coal and biomass, the effect on radiative and convective heat transfer and burnout

Energy Technology Data Exchange (ETDEWEB)

Smart, John P.; Patel, Rajeshriben; Riley, Gerry S. [RWEnpower, Windmill Hill Business Park, Whitehill Way, Swindon, Wiltshire SN5 6PB, England (United Kingdom)

2010-12-15

This paper focuses on results of co-firing coal and biomass under oxy-fuel combustion conditions on the RWEn 0.5 MWt Combustion Test Facility (CTF). Results are presented of radiative and convective heat transfer and burnout measurements. Two coals were fired: a South African coal and a Russian Coal under air and oxy-fuel firing conditions. The two coals were also co-fired with Shea Meal at a co-firing mass fraction of 20%. Shea Meal was also co-fired at a mass fraction of 40% and sawdust at 20% with the Russian Coal. An IFRF Aerodynamically Air Staged Burner (AASB) was used. The thermal input was maintained at 0.5 MWt for all conditions studied. The test matrix comprised of varying the Recycle Ratio (RR) between 65% and 75% and furnace exit O{sub 2} was maintained at 3%. Carbon-in-ash samples for burnout determination were also taken. Results show that the highest peak radiative heat flux and highest flame luminosity corresponded to the lowest recycle ratio. The effect of co-firing of biomass resulted in lower radiative heat fluxes for corresponding recycle ratios. Furthermore, the highest levels of radiative heat flux corresponded to the lowest convective heat flux. Results are compared to air firing and the air equivalent radiative and convective heat fluxes are fuel type dependent. Reasons for these differences are discussed in the main text. Burnout improves with biomass co-firing under both air and oxy-fuel firing conditions and burnout is also seen to improve under oxy-fuel firing conditions compared to air. (author)

Determining air quality and greenhouse gas impacts of hydrogen infrastructure and fuel cell vehicles.

Science.gov (United States)

Stephens-Romero, Shane; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald; Samuelsen, Scott

2009-12-01

Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 mug/m(3) in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario).

Inhalation exposure to jet fuel (JP8) among U.S. Air Force personnel.

Science.gov (United States)

Smith, Kristen W; Proctor, Susan P; Ozonoff, Al; McClean, Michael D

2010-10-01

As jet fuel is a common occupational exposure among military and civilian populations, this study was conducted to characterize jet fuel (JP8) exposure among active duty U.S. Air Force personnel. Personnel (n = 24) were divided a priori into high, moderate, and low exposure groups. Questionnaires and personal air samples (breathing zone) were collected from each worker over 3 consecutive days (72 worker-days) and analyzed for total hydrocarbons (THC), benzene, toluene, ethylbenzene, xylenes, and naphthalene. Air samples were collected from inside the fuel tank and analyzed for the same analytes. Linear mixed-effects models were used to evaluate the exposure data. Our results show that the correlation of THC (a measure of overall JP8 inhalation exposure) with all other analytes was moderate to strong in the a priori high and moderate exposure groups combined. Inhalation exposure to all analytes varied significantly by self-reported JP8 exposure (THC levels higher among workers reporting JP8 exposure), a priori exposure group (THC levels in high group > moderate group > low group), and more specific job task groupings (THC levels among workers in fuel systems hangar group > refueling maintenance group > fuel systems office group > fuel handling group > clinic group), with task groupings explaining the most between-worker variability. Among highly exposed workers, statistically significant job task-related predictors of inhalation exposure to THC indicated that increased time in the hangar, working close to the fuel tank (inside > less than 25 ft > greater than 25 ft), primary job (entrant > attendant/runner/fireguard > outside hangar), and performing various tasks near the fuel tank, such as searching for a leak, resulted in higher JP8 exposure. This study shows that while a priori exposure groups were useful in distinguishing JP8 exposure levels, job task-based categories should be considered in epidemiologic study designs to improve exposure classification. Finally

Modeling the burnout of solid polydisperse fuel under the conditions of external heat transfer

Science.gov (United States)

Skorik, I. A.; Goldobin, Yu. M.; Tolmachev, E. M.; Gal'perin, L. G.

2013-11-01

A self-similar burnout mode of solid polydisperse fuel is considered taking into consideration heat transfer between fuel particles, gases, and combustion chamber walls. A polydisperse composition of fuel is taken into account by introducing particle distribution functions by radiuses obtained for the kinetic and diffusion combustion modes. Equations for calculating the temperatures of particles and gases are presented, which are written for particles average with respect to their distribution functions by radiuses taking into account the fuel burnout ratio. The proposed equations take into consideration the influence of fuel composition, air excess factor, and gas recirculation ratio. Calculated graphs depicting the variation of particle and gas temperatures, and the fuel burnout ratio are presented for an anthracite-fired boiler.

Air quality assessment in Delhi: before and after CNG as fuel.

Science.gov (United States)

Chelani, Asha B; Devotta, Sukumar

2007-02-01

A number of policy measures have been activated in India in order to control the levels of air pollutants such as particulate matter, sulphur dioxide (SO(2)) and nitrogen dioxide (NO(2)). Delhi, which is one of the most polluted cities in the world, is also going through the implementation phase of the control policies. Ambient air quality data monitored during 2000 to 2003, at 10 sites in Delhi, were analyzed to assess the impact of implementation of these measures, specifically fuel change in vehicles. This paper presents the impact of policy measures on ambient air quality levels and also the source apportionment. CO and NO(2) concentration levels in ambient air are found to be associated with the mobile sources. The temporal variation of air quality data shows the significant effect of shift to CNG (Compressed Natural Gas) in vehicles.

Biomass fuel use and indoor air pollution in homes in Malawi

Science.gov (United States)

Fullerton, D G; Semple, S; Kalambo, F; Suseno, A; Malamba, R; Henderson, G; Ayres, J G; Gordon, S B

2009-01-01

Background: Air pollution from biomass fuels in Africa is a significant cause of mortality and morbidity both in adults and children. The work describes the nature and quantity of smoke exposure from biomass fuel in Malawian homes. Methods: Markers of indoor air quality were measured in 62 homes (31 rural and 31 urban) over a typical 24 h period. Four different devices were used (one gravimetric device, two photometric devices and a carbon monoxide (HOBO) monitor. Gravimetric samples were analysed for transition metal content. Data on cooking and lighting fuel type together with information on indicators of socioeconomic status were collected by questionnaire. Results: Respirable dust levels in both the urban and rural environment were high with the mean (SD) 24 h average levels being 226 μg/m3 (206 μg/m3). Data from real-time instruments indicated respirable dust concentrations were >250 μg/m3 for >1 h per day in 52% of rural homes and 17% of urban homes. Average carbon monoxide levels were significantly higher in urban compared with rural homes (6.14 ppm vs 1.87 ppm; p<0.001). The transition metal content of the smoke was low, with no significant difference found between urban and rural homes. Conclusions: Indoor air pollution levels in Malawian homes are high. Further investigation is justified because the levels that we have demonstrated are hazardous and are likely to be damaging to health. Interventions should be sought to reduce exposure to concentrations less harmful to health. PMID:19671533

Methodology for determining criteria for storing spent fuel in air

International Nuclear Information System (INIS)

Reid, C.R.; Gilbert, E.R.

1986-11-01

Dry storage in an air atmosphere is a method being considered for spent light water reactor (LWR) fuel as an alternative to storage in an inert gas environment. However, methods to predict fuel integrity based on oxidation behavior of the fuel first must be evaluated. The linear cumulative damage method has been proposed as a technique for defining storage criteria. Analysis of limited nonconstant temperature data on nonirradiated fuel samples indicates that this approach yields conservative results for a strictly decreasing-temperature history. On the other hand, the description of damage accumulation in terms of remaining life concepts provides a more general framework for making predictions of failure. Accordingly, a methodology for adapting remaining life concepts to UO 2 oxidation has been developed at Pacific Northwest Laboratory. Both the linear cumulative damage and the remaining life methods were used to predict oxidation results for spent fuel in which the temperature was decreased with time to simulate the temperature history in a dry storage cask. The numerical input to the methods was based on oxidation data generated with nonirradiated UO 2 pellets. The calculated maximum allowable storage temperatures are strongly dependent on the temperature-time profile and emphasize the conservatism inherent in the linear cumulative damage model. Additional nonconstant temperature data for spent fuel are needed to both validate the proposed methods and to predict temperatures applicable to actual spent fuel storage

Catalytic oxidative desulfurization of liquid hydrocarbon fuels using air

Science.gov (United States)

Sundararaman, Ramanathan

Conventional approaches to oxidative desulfurization of liquid hydrocarbons involve use of high-purity, expensive water soluble peroxide for oxidation of sulfur compounds followed by post-treatment for removal of oxidized sulfones by extraction. Both are associated with higher cost due to handling, storage of oxidants and yield loss with extraction and water separation, making the whole process more expensive. This thesis explores an oxidative desulfurization process using air as an oxidant followed by catalytic decomposition of sulfones thereby eliminating the aforementioned issues. Oxidation of sulfur compounds was realized by a two step process in which peroxides were first generated in-situ by catalytic air oxidation, followed by catalytic oxidation of S compounds using the peroxides generated in-situ completing the two step approach. By this technique it was feasible to oxidize over 90% of sulfur compounds present in real jet (520 ppmw S) and diesel (41 ppmw S) fuels. Screening of bulk and supported CuO based catalysts for peroxide generation using model aromatic compound representing diesel fuel showed that bulk CuO catalyst was more effective in producing peroxides with high yield and selectivity. Testing of three real diesel fuels obtained from different sources for air oxidation over bulk CuO catalyst showed different level of effectiveness for generating peroxides in-situ which was consistent with air oxidation of representative model aromatic compounds. Peroxides generated in-situ was then used as an oxidant to oxidize sulfur compounds present in the fuel over MoO3/SiO2 catalyst. 81% selectivity of peroxides for oxidation of sulfur compounds was observed on MoO3/SiO2 catalyst at 40 °C and under similar conditions MoO3/Al2O3 gave only 41% selectivity. This difference in selectivity might be related to the difference in the nature of active sites of MoO3 on SiO2 and Al2O 3 supports as suggested by H2-TPR and XRD analyses. Testing of supported and bulk Mg

The influence of Compression Ratio to Performance of Four Stroke Engine Use of Arak Bali as a Fuel

Directory of Open Access Journals (Sweden)

I Dewa Made Krishna Muku

2012-11-01

Full Text Available Arak bali is alternative fuel as ethanol. Ethanol has octane number 108. Octane number which was higher can over come adetonation, and can work at higher compression ratio. This experiment has done to now how the effect of compression ratiovariation to the performance four strokes engine by arak bali fuel. This research was done by changing the compressionratio that is 8,8 : 1, 8,9 : 1, 9 : 1 and 9,3 : 1. The change was done by reducing combustion chamber by scrap the cylinderhead. The result, for the used arak bali fuel to the vehicle is, if engine compression ratio to increase can be influence ofengine performance to be increase and engine fuel consumption to be decrease. For premium is, if engine compression ratioto increase to influence of engine performance to be decrease and engine fuel consumption to be increase.

Performance and Exhaust Emissions in a Natural-Gas Fueled Dual-Fuel Engine

Science.gov (United States)

Shioji, Masahiro; Ishiyama, Takuji; Ikegami, Makoto; Mitani, Shinichi; Shibata, Hiroaki

In order to establish the optimum fueling in a natural gas fueled dual fuel engine, experiments were done for some operational parameters on the engine performances and the exhaust emissions. The results show that the pilot fuel quantity should be increased and its injection timing should be advanced to suppress unburned hydrocarbon emission in the middle and low output range, while the quantity should be reduced and the timing retarded to avoid onset of knock at high loads. Unburned hydrocarbon emission and thermal efficiency are improved by avoiding too lean natural gas mixture by restricting intake charge air. However, the improvement is limited because the ignition of pilot fuel deteriorates with excessive throttling. It is concluded that an adequate combination of throttle control and equivalence ratio ensures low hydrocarbon emission and the thermal efficiency comparable to diesel operation.

Analysis of Fuel Injection and Atomization of a Hybrid Air-Blast Atomizer.

Science.gov (United States)

Ma, Peter; Esclape, Lucas; Buschhagen, Timo; Naik, Sameer; Gore, Jay; Lucht, Robert; Ihme, Matthias

2015-11-01

Fuel injection and atomization are of direct importance to the design of injector systems in aviation gas turbine engines. Primary and secondary breakup processes have significant influence on the drop-size distribution, fuel deposition, and flame stabilization, thereby directly affecting fuel conversion, combustion stability, and emission formation. The lack of predictive modeling capabilities for the reliable characterization of primary and secondary breakup mechanisms is still one of the main issues in improving injector systems. In this study, an unstructured Volume-of-Fluid method was used in conjunction with a Lagrangian-spray framework to conduct high-fidelity simulations of the breakup and atomization processes in a realistic gas turbine hybrid air blast atomizer. Results for injection with JP-8 aviation fuel are presented and compared to available experimental data. Financial support through the FAA National Jet Fuel Combustion Program is gratefully acknowledged.

Assessment of environmentally friendly fuel emissions from in-use vehicle exhaust: low-blend iso-stoichiometric GEM mixture as example.

Science.gov (United States)

Schifter, Isaac; Díaz-Gutiérrez, Luis; Rodríguez-Lara, René; González-Macías, Carmen; González-Macías, Uriel

2017-05-01

Gasoline-ethanol-methanol fuel blends were formulated with the same stoichiometric air-to-fuel ratio and volumetric energy concentration as any binary ethanol-gasoline blend. When the stoichiometric blends operated in a vehicle, the time period, injector voltage, and pressure for each fuel injection event in the engine corresponded to a given stoichiometric air-to-fuel ratio, and the load was essentially constant. Three low oxygen content iso-stoichiometric ternary gasoline-ethanol-methanol fuel blends were prepared, and the properties were compared with regular-type fuel without added oxygen. One of the ternary fuels was tested using a fleet of in-use vehicles for15 weeks and compared to neat gasoline without oxygenated compounds as a reference. Only a small number of publications have compared these ternary fuels in the same engine, and little data exist on the performance and emissions of in-use spark-ignition engines. The total hydrocarbon emissions observed was similar in both fuels, in addition to the calculated ozone forming potential of the tailpipe and evaporative emissions. In ozone non-attainment areas, the original purpose for oxygenate gasolines was to decrease carbon monoxide emissions. The results suggest that the strategy is less effective than expected because there still exist a great number of vehicles that have suffered the progressive deterioration of emissions and do not react to oxygenation, while new vehicles are equipped with sophisticated air/fuel control systems, and oxygenation does not improve combustion because the systems adjust the stoichiometric point, making it insensitive to the origin of the added excess oxygen (fuel or excess air). Graphical abstract Low level ternary blend of gasoline-ethanol-methanol were prepared with the same stoichiometric air-fuel ratio and volumetric energy concentration, based on the volumetric energy density of the pre-blended components. Exhaust and evaporative emissions was compared with a blend

Climate and air quality trade-offs in altering ship fuel sulfur content

Science.gov (United States)

Partanen, A.-I.; Laakso, A.; Schmidt, A.; Kokkola, H.; Kuokkanen, T.; Pietikäinen, J.-P.; Kerminen, V.-M.; Lehtinen, K. E. J.; Laakso, L.; Korhonen, H.

2013-08-01

Aerosol particles from shipping emissions both cool the climate and cause adverse health effects. The cooling effect is, however, declining because of shipping emission controls aiming to improve air quality. We used an aerosol-climate model ECHAM-HAMMOZ to test whether by altering ship fuel sulfur content, the present-day aerosol-induced cooling effect from shipping could be preserved while at the same time reducing premature mortality rates related to shipping emissions. We compared the climate and health effects of a present-day shipping emission scenario with (1) a simulation with strict emission controls in the coastal waters (ship fuel sulfur content of 0.1%) and twofold ship fuel sulfur content compared to current global average of 2.7% elsewhere; and (2) a scenario with global strict shipping emission controls (ship fuel sulfur content of 0.1% in coastal waters and 0.5% elsewhere) roughly corresponding to international agreements to be enforced by the year 2020. Scenario 1 had a slightly stronger aerosol-induced radiative flux perturbation (RFP) from shipping than the present-day scenario (-0.43 W m-2 vs. -0.39 W m-2) while reducing premature mortality from shipping by 69% (globally 34 900 deaths avoided per year). Scenario 2 decreased the RFP to -0.06 W m-2 and annual deaths by 96% (globally 48 200 deaths avoided per year) compared to present-day. A small difference in radiative effect (global mean of 0.04 W m-2) in the coastal regions between Scenario 1 and the present-day scenario imply that shipping emission regulation in the existing emission control areas should not be removed in hope of climate cooling. Our results show that the cooling effect of present-day emissions could be retained with simultaneous notable improvements in air quality, even though the shipping emissions from the open ocean clearly have a significant effect on continental air quality. However, increasing ship fuel sulfur content in the open ocean would violate existing

Solid fuels, indoor air quality and health: a major issue in developing countries

International Nuclear Information System (INIS)

Mandin, C.; Ezratty, V.

2009-01-01

This article intends to do a synthesis of knowledge about the relationship between the indoor air pollution and the use of solid fuels ( such wood or biomass) for heating and cooking, from publications since 200 by specifying the fuels, the pollutants and the concerned geographical areas as well as the sanitary effects and more generally the impact in term of public health. (N.C.)

Pneumatic hybridization of a diesel engine using compressed air storage for wind-diesel energy generation

International Nuclear Information System (INIS)

Basbous, Tammam; Younes, Rafic; Ilinca, Adrian; Perron, Jean

2012-01-01

In this paper, we are studying an innovative solution to reduce fuel consumption and production cost for electricity production by Diesel generators. The solution is particularly suitable for remote areas where the cost of energy is very high not only because of inherent cost of technology but also due to transportation costs. It has significant environmental benefits as the use of fossil fuels for electricity generation is a significant source of GHG (Greenhouse Gas) emissions. The use of hybrid systems that combine renewable sources, especially wind, and Diesel generators, reduces fuel consumption and operation cost and has environmental benefits. Adding a storage element to the hybrid system increases the penetration level of the renewable sources, that is the percentage of renewable energy in the overall production, and further improves fuel savings. In a previous work, we demonstrated that CAES (Compressed Air Energy Storage) has numerous advantages for hybrid wind-diesel systems due to its low cost, high power density and reliability. The pneumatic hybridization of the Diesel engine consists to introduce the CAES through the admission valve. We have proven that we can improve the combustion efficiency and therefore the fuel consumption by optimizing Air/Fuel ratio thanks to the CAES assistance. As a continuation of these previous analyses, we studied the effect of the intake pressure and temperature and the exhaust pressure on the thermodynamic cycle of the diesel engine and determined the values of these parameters that will optimize fuel consumption. -- Highlights: ► Fuel economy analysis of a simple pneumatic hybridization of the Diesel engine using stored compressed air. ► Thermodynamic analysis of the pneumatic hybridization of diesel engines for hybrid wind-diesel energy systems. ► Analysis of intake pressure and temperature of compressed air and exhaust pressure on pressure/temperature during Diesel thermodynamic cycle. ► Direct admission of

Effects of diluent admissions and intake air temperature in exhaust gas recirculation on the emissions of an indirect injection dual fuel engine

Energy Technology Data Exchange (ETDEWEB)

Abd-Alla, G.H.; Soliman, H.A.; Badr, O.A.; Abd-Rabbo, M.F. [Zagazig University, Cairo (Egypt). Shoubra Faculty of Engineering

2001-05-01

The operation of Diesel engines on gaseous fuels, commonly known as dual fuel engines, uses Diesel fuel as the pilot fuel and gaseous fuel (methane and sometimes propane in the present work) as the main fuel. The gaseous fuel was inducted in the intake manifold to mix with the intake air. The investigation was conducted on a high speed indirect injection (Ricardo-E6) dual fuel engine and was concerned with the effects of exhaust gas recirculation (EGR) on the dual fuel engine combustion and emissions, in particular, the effects of intake air temperature and diluent admissions (N{sub 2} and CO{sub 2}) on combustion and emissions. The use of diluents to displace oxygen (O{sub 2}) in the intake air resulted in a reduction in the O{sub 2} supplied to the engine, increased the inlet charge thermal capacity (thermal effect) and, potentially, CO{sub 2} and N{sub 2} participated in the combustion process (chemical effect). In a separate series of tests, the temperature of the engine inlet charge was raised gradually in order to simulate the effect of mixing hot EGR with the engine inlet gaseous fuel air mixture. It was found that the admission of diluents resulted in reductions in the exhaust oxides of nitrogen (NO{sub x}). Higher inlet charge temperature increases the exhaust NO{sub x} but reduces the unburned hydrocarbon emissions. Finally, when carbon dioxide was added to the inlet gaseous fuel air charge, large reductions in NO{sub x} were observed. (author)

Direct numerical simulations of the ignition of lean primary reference fuel/air mixtures with temperature inhomogeneities

KAUST Repository

Luong, Minhbau

2013-10-01

The effects of fuel composition, thermal stratification, and turbulence on the ignition of lean homogeneous primary reference fuel (PRF)/air mixtures under the conditions of constant volume and elevated pressure are investigated by direct numerical simulations (DNSs) with a new 116-species reduced kinetic mechanism. Two-dimensional DNSs were performed in a fixed volume with a two-dimensional isotropic velocity spectrum and temperature fluctuations superimposed on the initial scalar fields with different fuel compositions to elucidate the influence of variations in the initial temperature fluctuation and turbulence intensity on the ignition of three different lean PRF/air mixtures. In general, it was found that the mean heat release rate increases slowly and the overall combustion occurs fast with increasing thermal stratification regardless of the fuel composition under elevated pressure and temperature conditions. In addition, the effect of the fuel composition on the ignition characteristics of PRF/air mixtures was found to vanish with increasing thermal stratification. Chemical explosive mode (CEM), displacement speed, and Damköhler number analyses revealed that the high degree of thermal stratification induces deflagration rather than spontaneous ignition at the reaction fronts, rendering the mean heat release rate more distributed over time subsequent to thermal runaway occurring at the highest temperature regions in the domain. These analyses also revealed that the vanishing of the fuel effect under the high degree of thermal stratification is caused by the nearly identical propagation characteristics of deflagrations of different PRF/air mixtures. It was also found that high intensity and short-timescale turbulence can effectively homogenize mixtures such that the overall ignition is apt to occur by spontaneous ignition. These results suggest that large thermal stratification leads to smooth operation of homogeneous charge compression-ignition (HCCI

An experimental investigation on engine performance and emissions of a supercharged H{sub 2}-diesel dual-fuel engine

Energy Technology Data Exchange (ETDEWEB)

Roy, Murari Mohon [Rajshahi University of Engineering and Technology (JSPS Research Fellow, Okayama University), Tsushima-Naka 3, Okayama 700-8530 (Japan); Department of Mechanical Engineering, Okayama University, Tsushima-Naka 3, Okayama 700-8530 (Japan); Tomita, Eiji; Kawahara, Nobuyuki; Harada, Yuji [Department of Mechanical Engineering, Okayama University, Tsushima-Naka 3, Okayama 700-8530 (Japan); Sakane, Atsushi [Mitsui Engineering and Shipbuilding Co. Ltd., 6-4 Tsukiji 5-chome, Chuo-ku, Tokyo (Japan)

2010-01-15

This study investigated the engine performance and emissions of a supercharged engine fueled by hydrogen and ignited by a pilot amount of diesel fuel in dual-fuel mode. The engine was tested for use as a cogeneration engine, so power output while maintaining a reasonable thermal efficiency was important. Experiments were carried out at a constant pilot injection pressure and pilot quantity for different fuel-air equivalence ratios and at various injection timings without and with charge dilution. The experimental strategy was to optimize the injection timing to maximize engine power at different fuel-air equivalence ratios without knocking and within the limit of the maximum cylinder pressure. The engine was tested first with hydrogen-operation condition up to the maximum possible fuel-air equivalence ratio of 0.3. A maximum IMEP of 908 kPa and a thermal efficiency of about 42% were obtained. Equivalence ratio could not be further increased due to knocking of the engine. The emission of CO was only about 5 ppm, and that of HC was about 15 ppm. However, the NOx emissions were high, 100-200 ppm or more. The charge dilution by N{sub 2} was then performed to obtain lower NOx emissions. The 100% reduction of NOx was achieved. Due to the dilution by N{sub 2} gas, higher amount of energy could be supplied from hydrogen without knocking, and about 13% higher IMEP was produced than without charge dilution. (author)

Ethanol and air quality: influence of fuel ethanol content on emissions and fuel economy of flexible fuel vehicles.

Science.gov (United States)

Hubbard, Carolyn P; Anderson, James E; Wallington, Timothy J

2014-01-01

Engine-out and tailpipe emissions of NOx, CO, nonmethane hydrocarbons (NMHC), nonmethane organic gases (NMOG), total hydrocarbons (THC), methane, ethene, acetaldehyde, formaldehyde, ethanol, N2O, and NH3 from a 2006 model year Mercury Grand Marquis flexible fuel vehicle (FFV) operating on E0, E10, E20, E30, E40, E55, and E80 on a chassis dynamometer are reported. With increasing ethanol content in the fuel, the tailpipe emissions of ethanol, acetaldehyde, formaldehyde, methane, and ammonia increased; NOx and NMHC decreased; while CO, ethene, and N2O emissions were not discernibly affected. NMOG and THC emissions displayed a pronounced minimum with midlevel (E20-E40) ethanol blends; 25-35% lower than for E0 or E80. Emissions of NOx decreased by approximately 50% as the ethanol content increased from E0 to E30-E40, with no further decrease seen with E55 or E80. We demonstrate that emission trends from FFVs are explained by fuel chemistry and engine calibration effects. Fuel chemistry effects are fundamental in nature; the same trend of increased ethanol, acetaldehyde, formaldehyde, and CH4 emissions and decreased NMHC and benzene emissions are expected for all FFVs. Engine calibration effects are manufacturer and model specific; emission trends for NOx, THC, and NMOG will not be the same for all FFVs. Implications for air quality are discussed.

Impact of co-flow air on buoyant diffusion flames flicker

Energy Technology Data Exchange (ETDEWEB)

Gohari Darabkhani, H., E-mail: h.g.darabkhani@gmail.com [School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, Manchester M13 9PL (United Kingdom); Wang, Q.; Chen, L.; Zhang, Y. [Mechanical Engineering Department, University of Sheffield, Mapping Street, Sheffield S1 3JD (United Kingdom)

2011-08-15

Highlights: {yields} We present the co-flow effects on flickering behaviour of diffusion flames. {yields} Co-flow air is shown to fully suppress the buoyancy driven flame oscillations. {yields} Schlieren and PIV illustrate the shift of outer vortices beyond the flame zone. {yields} Stability controlling parameter as a ratio of air to fuel velocities is presented. {yields} Equation for linear increase in flickering frequency by co-flow air is presented. - Abstract: This paper describes experimental investigation of co-flow air velocity effects on the flickering behaviour of laminar non-lifted methane diffusion flames. Chemiluminescence, high-speed photography, schlieren and Particle Imaging Velocimetry (PIV), have been used to study the changes in the flame/vortex interactions as well as the flame flickering frequency and magnitude by the co-flow air. Four cases of methane flow rates at different co-flow air velocities are investigated. It has been observed that the flame dynamics and stability of co-flow diffusion flames are strongly affected by the co-flow air velocity. When the co-flow velocity has reached a certain value the buoyancy driven flame oscillation was completely suppressed. The schlieren and PIV imaging have revealed that the co-flow of air is able to push the initiation point of the outer toroidal vortices beyond the visible flame to create a very steady laminar flow region in the reaction zone. Then the buoyancy driven instability is only effective in the plume of hot gases above the visible flame. It is observed that a higher co-flow rate is needed in order to suppress the flame flickering at a higher fuel flow rate. Therefore the ratio of the air velocity to the fuel velocity, {gamma}, is a stability controlling parameter. The velocity ratio, {gamma}, was found to be 0.72 for the range of tested flow rates. The dominant flickering frequency was observed to increase linearly with the co-flow rate (a) as; f = 0.33a + 11. The frequency amplitudes

Gamma-ray spectrometric measurements of fission rate ratios between fresh and burnt fuel following irradiation in a zero-power reactor

Energy Technology Data Exchange (ETDEWEB)

Kröhnert, H., E-mail: hanna.kroehnert@ensi.ch [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Perret, G.; Murphy, M.F. [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); Chawla, R. [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

2013-01-11

The gamma-ray activity from short-lived fission products has been measured in fresh and burnt UO{sub 2} fuel samples after irradiation in a zero-power reactor. For the first time, short-lived gamma-ray activity from fresh and burnt fuel has been compared and fresh-to-burnt fuel fission rate ratios have been derived. For the measurements, well characterized fresh and burnt fuel samples, with burn-ups up to 46 GWd/t, were irradiated in the zero-power research reactor PROTEUS. Fission rate ratios were derived based on the counting of high-energy gamma-rays above 2200 keV, in order to discriminate against the high intrinsic activity of the burnt fuel. This paper presents the measured fresh-to-burnt fuel fission rate ratios based on the {sup 142}La (2542 keV), {sup 89}Rb (2570 keV), {sup 138}Cs (2640 keV) and {sup 95}Y (3576 keV) high-energy gamma-ray lines. Comparisons are made with the results of Monte Carlo modeling of the experimental configuration, carried out using the MCNPX code. The measured fission rate ratios have 1σ uncertainties of 1.7–3.4%. The comparisons with calculated predictions show an agreement within 1–3σ, although there appears to be a slight bias (∼3%).

Characterization of inhalation exposure to jet fuel among U.S. Air Force personnel.

Science.gov (United States)

Merchant-Borna, Kian; Rodrigues, Ema G; Smith, Kristen W; Proctor, Susan P; McClean, Michael D

2012-07-01

Jet propulsion fuel-8 (JP-8) is the primary jet fuel used by the US military, collectively consuming ~2.5 billion gallons annually. Previous reports suggest that JP-8 is potentially toxic to the immune, respiratory, and nervous systems. The objectives of this study were to evaluate inhalation exposure to JP-8 constituents among active duty United States Air Force (USAF) personnel while performing job-related tasks, identify significant predictors of inhalation exposure to JP-8, and evaluate the extent to which surrogate exposure classifications were predictive of measured JP-8 exposures. Seventy-three full-time USAF personnel from three different air force bases were monitored during four consecutive workdays where personal air samples were collected and analyzed for benzene, ethylbenzene, toluene, xylenes, total hydrocarbons (THC), and naphthalene. The participants were categorized a priori into high- and low-exposure groups, based on their exposure to JP-8 during their typical workday. Additional JP-8 exposure categories included job title groups and self-reported exposure to JP-8. Linear mixed-effects models were used to evaluate predictors of personal air concentrations. The concentrations of THC in air were significantly different between a priori exposure groups (2.6 mg m(-3) in high group versus 0.5 mg m(-3) in low, P fuel distribution/maintenance, though self-reported exposure to JP-8 was an even stronger predictor of measured exposure in models that explained 72% (THC) and 67% (naphthalene) of between-worker variability. In fact, both self-report JP-8 exposure and a priori exposure groups explained more between-worker variability than job categories. Personal exposure to JP-8 varied by job and was positively associated with the relative humidity. However, self-reported exposure to JP-8 was an even stronger predictor of measured exposure than job title categories, suggesting that self-reported JP-8 exposure is a valid surrogate metric of exposure when

Solid oxide fuel cells and hydrogen production

International Nuclear Information System (INIS)

Dogan, F.

2009-01-01

'Full text': A single-chamber solid oxide fuel cell (SC-SOFC), operating in a mixture of fuel and oxidant gases, provides several advantages over the conventional SOFC such as simplified cell structure (no sealing required). SC-SOFC allows using a variety of fuels without carbon deposition by selecting appropriate electrode materials and cell operating conditions. The operating conditions of single chamber SOFC was studied using hydrocarbon-air gas mixtures for a cell composed of NiO-YSZ / YSZ / LSCF-Ag. The cell performance and catalytic activity of the anode was measured at various gas flow rates. The results showed that the open-circuit voltage and the power density increased as the gas flow rate increased. Relatively high power densities up to 660 mW/cm 2 were obtained in a SC-SOFC using porous YSZ electrolytes instead of dense electrolytes required for operation of a double chamber SOFC. In addition to propane- or methane-air mixtures as a fuel source, the cells were also tested in a double chamber configuration using hydrogen-air mixtures by controlling the hydrogen/air ratio at the cathode and the anode. Simulation of single chamber conditions in double chamber configurations allows distinguishing and better understanding of the electrode reactions in the presence of mixed gases. Recent research efforts; the effect of hydrogen-air mixtures as a fuel source on the performance of anode and cathode materials in single-chamber and double-chamber SOFC configurations,will be presented. The presentation will address a review on hydrogen production by utilizing of reversible SOFC systems. (author)

Effect of compression ratio, equivalence ratio and engine speed on the performance and emission characteristics of a spark ignition engine using hydrogen as a fuel

Energy Technology Data Exchange (ETDEWEB)

Sadiq Al-Baghdadi, M.A.R. [University of Babylon (Iraq). Dept. of Mechanical Engineering

2004-12-01

The present energy situation has stimulated active research interest in non-petroleum and non-polluting fuels, particularly for transportation, power generation, and agricultural sectors. Researchers have found that hydrogen presents the best and an unprecedented solution to the energy crises and pollution problems, due to its superior combustion qualities and availability. This paper discusses analytically and provides data on the effect of compression ratio, equivalence ratio and engine speed on the engine performance, emissions and pre-ignition limits of a spark ignition engine operating on hydrogen fuel. These data are important in order to understand the interaction between engine performance and emission parameters, which will help engine designers when designing for hydrogen. (author)

Combinatorial electrochemical cell array for high throughput screening of micro-fuel-cells and metal/air batteries.

Science.gov (United States)

Jiang, Rongzhong

2007-07-01

An electrochemical cell array was designed that contains a common air electrode and 16 microanodes for high throughput screening of both fuel cells (based on polymer electrolyte membrane) and metal/air batteries (based on liquid electrolyte). Electrode materials can easily be coated on the anodes of the electrochemical cell array and screened by switching a graphite probe from one cell to the others. The electrochemical cell array was used to study direct methanol fuel cells (DMFCs), including high throughput screening of electrode catalysts and determination of optimum operating conditions. For screening of DMFCs, there is about 6% relative standard deviation (percentage of standard deviation versus mean value) for discharge current from 10 to 20 mAcm(2). The electrochemical cell array was also used to study tin/air batteries. The effect of Cu content in the anode electrode on the discharge performance of the tin/air battery was investigated. The relative standard deviations for screening of metal/air battery (based on zinc/air) are 2.4%, 3.6%, and 5.1% for discharge current at 50, 100, and 150 mAcm(2), respectively.

Development of an engine control system using city gas and biogas fuel mixture

International Nuclear Information System (INIS)

Yamasaki, Yudai; Kanno, Masanobu; Suzuki, Yoshitaka; Kaneko, Shigehiko

2013-01-01

Highlights: ► The gas engine control system was developed using both city gas and biogas flexibly. ► The developed control system corporates with an original controller. ► The target value of O 2 emission is decided by Wobbe index of mixture fuel and load. ► The controller achieved stable operation for fuel mix ratio and load changing. -- Abstract: In this paper, a gas engine system capable of stable operation at any mix ratio of city gas 13A and biogas was developed. The gas engine system consists of a spark-ignition gas engine, an additional electric throttle valve for fuel and our own control algorithm. The engine is a 3-cylinder 1.6-l engine that was originally used for co-generation, and the fuel throttle valve was added to respond to different fuel compositions. The control algorithm was also designed to adjust the fuel and air ratio to attain a higher generation efficiency and lower NOx emission with different mix ratios of city gas 13A, biogas and load. Before developing the controller, the effect of the mix ratio on generation efficiency and NOx emission was investigated under various load conditions. The following summarizes the experimental results: a control algorithm using the Wobbe index for mixed fuels was formulated; this index determines the target fuel-to-air ratio. Next, operation tests were performed under varying fuel mix ratios and loads by applying the control algorithm to the gas engine. The target engine rotational speed and exhaust O 2 concentration was realized in 5 s when the biogas fraction varied from 20% to 40% and from 70% to 40%. When the load was also varied from 9.4 kW to 0.5 kW and from 0.5 kW to 9.4 kW at a constant rate, the rotational speed and exhaust O 2 concentration achieved the target values in 20 s. Under both transient operation conditions, the engine system met the NOx emission requirement, and the results indicate that the simple hardware modification to a conventional gas engine and our original control

PAH diagnostic ratios for the identification of pollution emission sources

International Nuclear Information System (INIS)

Tobiszewski, Marek; Namieśnik, Jacek

2012-01-01

Polycyclic aromatic hydrocarbon (PAH) diagnostic ratios have recently come into common use as a tool for identifying and assessing pollution emission sources. Some diagnostic ratios are based on parent PAHs, others on the proportions of alkyl-substituted to non-substituted molecules. The ratios are applicable to PAHs determined in different environmental media: air (gas + particle phase), water, sediment, soil, as well as biomonitor organisms such as leaves or coniferous needles, and mussels. These ratios distinguish PAH pollution originating from petroleum products, petroleum combustion and biomass or coal burning. The compounds involved in each ratio have the same molar mass, so it is assumed they have similar physicochemical properties. Numerous studies show that diagnostic ratios change in value to different extents during phase transfers and environmental degradation. The paper reviews applications of diagnostic ratios, comments on their use and specifies their limitations. - Highlights: ► PAH diagnostic ratios may identify pollution coming from petroleum spills, fuel combustion and coal or biomass burning. ► They are sensitive to changes during PAHs environmental fate processes. ► Some diagnostic ratios are of limited value due to fast photodegradation of one of the compounds. - The paper reviews PAH diagnostic ratios that are applied to identify pollution emission originating from petroleum products, fuel combustion or coal and biomass burning.

Alpha-in-air monitor for continuous monitoring based on alpha to beta ratio

International Nuclear Information System (INIS)

Somayaji, K.S.; Venkataramani, R.; Swaminathan, N.; Pushparaja

1997-01-01

Measurement of long-lived alpha activity collected on a filter paper in continuous air monitoring of ambient working environment is difficult due to interference from much larger concentrations of short-lived alpha emitting daughter products of 222 Rn and 220 Rn. However, the ratio between the natural alpha and beta activity is approximately constant and this constancy of the ratio is used to discriminate against short-lived natural radioactivity in continuous air monitoring. Detection system was specially designed for the purpose of simultaneous counting of alpha and beta activity deposited on the filter paper during continuous monitoring. The activity ratios were calculated and plotted against the monitoring duration up to about six hours. Monitoring was carried out in three facilities with different ventilation conditions. Presence of any long-lived alpha contamination on the filter paper results in increase in the alpha to beta ratio. Long-lived 239 Pu contamination of about 16 DAC.h could be detected after about 45 minutes of commencement of the sampling. The experimental results using prototype units have shown that the approach of using alpha to beta activity ratio method to detect long-lived alpha activity in the presence of short-lived natural activity is satisfactory. (author)

Technique for Selecting Optimum Fan Compression Ratio based on the Effective Power Plant Parameters

Directory of Open Access Journals (Sweden)

I. I. Kondrashov

2016-01-01

Full Text Available Nowadays, civilian aircrafts occupy the major share of global aviation industry market. As to medium and long - haul aircrafts, turbofans with separate exhaust streams are widely used. Here, fuel efficiency is the main criterion of this engine. The paper presents the research results of the mutual influence of fan pressure ratio and bypass ratio on the effective specific fuel consumption. Shows the increasing bypass ratio to be a rational step for reducing the fuel consumption. Also considers the basic features of engines with a high bypass ratio. Among the other working process parameters, fan pressure ratio and bypass ratio are the most relevant for consideration as they are the most structural variables at a given level of technical excellence. The paper presents the dependence of the nacelle drag coefficient on the engine bypass ratio. For computation were adopted the projected parameters of prospective turbofans to be used in the power plant of the 180-seat medium-haul aircraft. Computation of the engine cycle was performed in Mathcad using these data, with fan pressure ratio and bypass ratio being varied. The combustion chamber gas temperature, the overall pressure ratio and engine thrust remained constant. Pressure loss coefficients, the efficiency of the engine components and the amount of air taken for cooling also remained constant. The optimal parameters corresponding to the minimum effective specific fuel consumption were found as the result of computation. The paper gives recommendations for adjusting optimal parameters, depending on the considered external factors, such as weight of engine and required fuel reserve. The obtained data can be used to estimate parameters of future turbofan engines with high bypass ratio.

Impacts of using reformulated and oxygenated fuel blends on the regional air quality of the upper Rhine valley

Directory of Open Access Journals (Sweden)

J.-F. Vinuesa

2006-01-01

Full Text Available The effects of using three alternative gasoline fuel blends on regional air quality of the upper Rhine valley have been investigated. The first of the tested fuels is oxygenated by addition of ethyl-tertio-butyl ether (ETBE, the second is based on a reformulation of its composition and the third on is both oxygenated and reformulated. The upper Rhine valley is a very sensitive region for pollution episodes and several meteorological and air quality studies have already been performed. High temporal and spatial emission inventories are available allowing relevant and realistic modifications of the emission inventories. The calculation period, i.e., 11 May 1998, corresponds to a regional photochemical ozone pollution episode during which ozone concentrations exceeded several times the information threshold of the ozone directive of the European Union (180 μg m-3 as 1 hourly average. New emission inventories are set up using specific emission factors related to the alternative fuels by varying the fraction of gasoline passenger cars (from 50% to 100% using the three fuel blends. Then air quality modeling simulations are performed using these emission inventories over the upper Rhine valley. The impact of alternative fuels on regional air quality is evaluated by comparing these simulations with the one using a reference emission inventory, e.g., where no modifications of the fuel composition are included. The results are analyzed by focusing on peak levels and daily averaged concentrations. The use of the alternative fuels leads to general reductions of ozone and volatile organic compounds (VOC and increases of NOx levels. We found different behaviors related to the type of the area of concern i.e. rural or urban. The impacts on ozone are enhanced in urban areas where 15% reduction of the ozone peak and daily averaged concentrations can be reached. This behavior is similar for the NOx for which, in addition, an increase of the levels can be noted

Multiple Threats to Child Health from Fossil Fuel Combustion: Impacts of Air Pollution and Climate Change.

Science.gov (United States)

Perera, Frederica P

2017-02-01

Approaches to estimating and addressing the risk to children from fossil fuel combustion have been fragmented, tending to focus either on the toxic air emissions or on climate change. Yet developing children, and especially poor children, now bear a disproportionate burden of disease from both environmental pollution and climate change due to fossil fuel combustion. This commentary summarizes the robust scientific evidence regarding the multiple current and projected health impacts of fossil fuel combustion on the young to make the case for a holistic, child-centered energy and climate policy that addresses the full array of physical and psychosocial stressors resulting from fossil fuel pollution. The data summarized here show that by sharply reducing our dependence on fossil fuels we would achieve highly significant health and economic benefits for our children and their future. These benefits would occur immediately and also play out over the life course and potentially across generations. Going beyond the powerful scientific and economic arguments for urgent action to reduce the burning of fossil fuels is the strong moral imperative to protect our most vulnerable populations. Citation: Perera FP. 2017. Multiple threats to child health from fossil fuel combustion: impacts of air pollution and climate change. Environ Health Perspect 125:141-148; http://dx.doi.org/10.1289/EHP299.

Mechanism of influence water vapor on combustion characteristics of propane-air mixture

Science.gov (United States)

Larionov, V. M.; Mitrofanov, G. A.; Sachovskii, A. V.; Kozar, N. K.

2016-01-01

The article discusses the results of an experimental study of the effect of water vapor at the flame temperature. Propane-butane mixture with air is burning on a modified Bunsen burner. Steam temperature was varied from 180 to 260 degrees. Combustion parameters changed by steam temperature and its proportion in the mixture with the fuel. The fuel-air mixture is burned in the excess air ratio of 0.1. It has been established that the injection of steam changes the characteristics of combustion fuel-air mixture and increase the combustion temperature. The concentration of CO in the combustion products is substantially reduced. Raising the temperature in the combustion zone is associated with increased enthalpy of the fuel by the added steam enthalpy. Reducing the concentration of CO is caused by decrease in the average temperature in the combustion zone by applying steam. Concentration of active hydrogen radicals and oxygen increases in the combustion zone. That has a positive effect on the process of combustion.

Passive-X-ray fluorescence determination of the plutonium and uranium ratio in burnt-up fuel

International Nuclear Information System (INIS)

Zhelev, Z.

1983-05-01

This non-destructive method was proposed for comparatively simple and not labour-intensive determination of the Pu and U ratio in WWER-440 (PWR type) reactor spent fuel. For this purpose the mini-tablets (2mm and length 5mm) were irradiated for 65 and 130 days in dry channel of the WWER-440 reactor passed through its active core. The ratio of Pu and U and ratio of the isotopes 134 Cs and 137 Cs were determined by means of KX-rays and gamma-scanning analyses correspondingly. It was shown that there was a simple functional dependance between the ratio of Pu and U and the ratio of Cs isotopes

Air Oxidation Behaviors of Zircaloy-4 Cladding During a LOCA In Spent Fuel Pool

International Nuclear Information System (INIS)

Bang, Je Geon; Chun, Tae Hyun; Kim, Sun Ki; Koo, Yang Hyun

2014-01-01

It is well known that air oxidation induces a serious degradation of the Zircaloy cladding material, compared with steam oxidation. From the oxidant point of view, in comparison with steam, chemical heat release during oxidation in air is higher by 80%, which may lead to a more rapid degradation of the Zircaloy cladding, and further evolution of the accident.. Additionally, the oxidation kinetics in air is much faster than in steam due to the formation of non-protective oxide layer. From the safety point of view, the barrier effect of the cladding against release of fission products is lost much earlier in air compared to steam. The objective of this study is to investigate the oxidation behaviors of fuel cladding in two different conditions such as isothermal and transient condition and to generate its kinetic data under an accident condition in the spent fuel pool. In this study, the oxidation behaviors and its kinetics of the Zircaloy-4 were investigated in air environment for various air ingress scenarios in the temperature range 600 .deg. C-1,400 .deg. C by thermo-gravimetric analysis. In this study, the oxidation behaviors of the Zircaloy-4 for both isothermal condition and transient condition were investigated in air environment. In comparison with isothermal condition, the retardation of oxidation rate in transient condition was observed at both 1,200 .deg. C and 1,400 .deg. C. This seems to be ascribed to the effect of thin oxide formed during a heating

Evaporative Air Coolers Optimization for Energy Consumption Reduction and Energy Efficiency Ratio Increment

OpenAIRE

Leila Torkaman; Nasser Ghassembaglou

2015-01-01

Significant quota of Municipal Electrical Energy consumption is related to Decentralized Air Conditioning which is mostly provided by evaporative coolers. So the aim is to optimize design of air conditioners to increase their efficiencies. To achieve this goal, results of practical standardized tests for 40 evaporative coolers in different types collected and simultaneously results for same coolers based on one of EER (Energy Efficiency Ratio) modeling styles are figured ...

Study of recent fuel oil cost in air lines (Part 2). Saikin no airline no nenyuhi ni kansuru ichikosatsu (2); Nenryo shohi to hiyo tai koka

Energy Technology Data Exchange (ETDEWEB)

Tanabe, Yoshikazu.

1989-03-01

Through an arrangement of published data about American air lines during 1985 through 1987, the overall expense vs. transportation fee (expense vs. effect) was studied as a main viewpoint. As a result, the fuel oil cost, even in case of wide fuselage plane, high in transportation efficiency, was high in ratio, 32 to 52% (3 to 5 times as high as that 12 to 14 years ago), and fluctuated connectedly with the oil price. While the jet fuel price fluctuated connectedly with the oil price per equal volume with 1.3 to 1.4 of price ratio. Further, the flight range ratio was recorded to be approx. 0.06 to 0.24 km/kg. While the transportation efficiency was lower than approx. 5000kg*km/kg with a wide range of overall expense, approx. 9 to 87 cents per compensative transportation ton*km. Because even a sudden decrease in transportation quantity did not decrease the overall expense, it was known to be important in management to secure the transportation quantity. 30 refs., 15 figs., 1 tab.

Simulation of the charge ratio of cosmic ray muons in extensive air showers using CORSIKA

Energy Technology Data Exchange (ETDEWEB)

Ochilo, Livingstone [University of Siegen (Germany); Kenyatta University, Nairobi (Kenya); Hashim, Nadir; Okumu, John [Kenyatta University, Nairobi (Kenya)

2013-07-01

The interaction of primary cosmic rays in the atmosphere produces, among other particles, pions and kaons. They decay to muons, which form an important component of extensive air showers. The ratio of positively to negatively charged muons, called the muon charge ratio, provides important information about the cosmic ray interactions in the atmosphere. In this study, the theoretical hadronic interaction models in the cosmic ray simulation code CORSIKA have been used to study the charge ratio of cosmic ray muons simulated in extensive air showers. An East - West effect on the charge ratio of simulated cosmic ray muons is observed. It is more pronounced for inclined and low-energy muons (momentum less than 100 GeV/c and zenith angle greater than 80 ). Experimental data from ''MINOS Near'' experiment gives similar results.

Hydrogen-ethanol blending as an alternative fuel of spark ignition engines

Energy Technology Data Exchange (ETDEWEB)

Al-Baghdadi, M.A.S. [University of Babylon (Iraq). Dept. of Mechanical Engineering

2003-07-01

The performance and pollutant emission of a four-stroke spark ignition engine using hydrogen-ethanol blends as fuel have been studied. The tests were performed using 2, 4, 6, 8, 1 0 and 12 mass% hydrogen-ethanol blends. Gasoline fuel was used as a basis for comparison. The effect of using different blends of hydrogen-ethanol on engine power, specific fuel consumption, CO and NO{sub x} emission was studied. Operating test results for a range of compression ratio (CR) and equivalent ratio are presented. The results show that the supplemental hydrogen in the ethanol-air mixture improves the combustion process and hence improves the combustion efficiency, expands the range of combustibility of the ethanol fuel, increases the power, reduces the s.f.c. and reduces toxic emissions. The important improvement of hydrogen addition is to reduce the s.f.c. of ethanol engines. Results were compared to those with gasoline fuel at 7 CR and stoichiometric equivalence ratio. (author)

Impact of domestic air pollution from cooking fuel on respiratory allergies in children in India

Energy Technology Data Exchange (ETDEWEB)

Kumar, R.; Nagar, J.K.; Raj, N.; Kumar, P.; Kushwah, A.S.; Meena, M.; Gaur, S.N. [University of Delhi, Delhi (India)

2008-12-15

This study undertaken in India was aimed at identifying the effects of the indoor air pollutants SO{sub 2}, NO{sub 2} and total suspended particulate matter (SPM) generated from fuel used for cooking on respiratory allergy in children in Delhi. A total of 3,456 children were examined (59.2% male and 40.8% female). Among these, 31.2% of the children's families were using biomass fuels for cooking and 68.8% were using liquefied petroleum gas. Levels of indoor SO{sub 2}, NO{sub 2} and SPM, measured using a Handy Air Sampler (Low Volume Sampler), were 4.60 {+-} 5.66 {mu}g/m{sup 3}, 30.70 {+-} 23.95 {mu}g/m{sup 3} and 705 {+-} 441.6 {mu}g/m{sup 3}, respectively. The mean level of indoor SO{sub 2} was significantly higher (p = 0.016) for families using biomass fuels (coal, wood, cow dung cakes and kerosene) for cooking as compared to families using LP gas. The mean level of indoor NO{sub 2} for families using biomass fuels for cooking was significantly higher in I.T.O. (p = 0.003) and Janakpuri (p = 0.007), while indoor SPM was significantly higher in Ashok Vihar (p = 0.039) and I.T.O. (p = 0.001), when compared to families using LP gas. Diagnoses of asthma, rhinitis and upper respiratory tract infection (URTI) were made in 7.7%, 26.1% and 22.1% of children, respectively. Respiratory allergies in children, which included asthma, rhinitis and URTI, could be associated with both types of fuels (liquefied petroleum gas (LPG) and biomass) used for cooking in the different study areas. This study suggests that biomass fuels increased the concentrations of indoor air pollutants that cause asthma, rhinitis and URTI in children. LP gas smoke was also associated with respiratory allergy.

Influence of ethanol admixture on the determination of equivalence ratios in DISI engines by laser-induced fluorescence.

Science.gov (United States)

Storch, Michael; Lind, Susanne; Will, Stefan; Zigan, Lars

2016-10-20

In this work, the planar laser-induced fluorescence of a fuel tracer is applied for the analysis of mixture formation for various ethanol/iso-octane blends in a direct-injection spark-ignition (DISI) engine. The tracer triethylamine (TEA) was added to pure iso-octane and ethanol as well as to their blends E20 and E85 for the measurement of the fuel/air ratio. In general, ethanol blending strongly affects the mixture formation process, which is caused by specific physical fuel properties influencing the evaporation process of ethanol in comparison to iso-octane. As interactions of the fuel and tracer fluorescence appear possible, TEA fluorescence was studied for different fuel blends in a cuvette, in a calibration cell under constant conditions, and in an optically accessible internal combustion engine at late injection timing. It was found that ethanol blending strongly affects the fluorescence intensity of TEA in the liquid phase, which can be explained by the interaction of the tracer and ethanol molecules. However, in the gas phase a quantification of the fuel/air ratio is possible for different ethanol fuel blends, which is demonstrated in a DISI engine. Under stratified charge conditions the engine results showed a significant impact of a high amount of ethanol on the mixture formation process, leading to a leaner mixture in comparison to iso-octane.

Alvar engine. An engine with variable compression ratio. Experiments and tests

Energy Technology Data Exchange (ETDEWEB)

Erlandsson, Olof

1998-09-01

This report is focused on tests with Variable Compression Ratio (VCR) engines, according to the Alvar engine principle. Variable compression ratio means an engine design where it is possible to change the nominal compression ratio. The purpose is to increase the fuel efficiency at part load by increasing the compression ratio. At maximum load, and maybe supercharging with for example turbocharger, it is not possible to keep a high compression ratio because of the knock phenomena. Knock is a shock wave caused by self-ignition of the fuel-air mix. If knock occurs, the engine will be exposed to a destructive load. Because of the reasons mentioned it would be an advantage if it would be possible to change the compression ratio continuously when the load changes. The Alvar engine provides a solution for variable compression ratio based on well-known engine components. This paper provides information about efficiency and emission characteristics from tests with two Alvar engines. Results from tests with a phase shift mechanism (for automatic compression ratio control) for the Alvar engine are also reviewed Examination paper. 5 refs, 23 figs, 2 tabs, 5 appendices

Quantitative planar laser-induced fluorescence imaging of multi-component fuel/air mixing in a firing gasoline-direct-injection engine: Effects of residual exhaust gas on quantitative PLIF

Energy Technology Data Exchange (ETDEWEB)

Williams, Ben; Ewart, Paul [Department of Physics, Oxford University, Parks Road, Oxford OX1 3PU (United Kingdom); Wang, Xiaowei; Stone, Richard [Department of Engineering Science, Oxford University, Parks Road, Oxford OX1 3PJ (United Kingdom); Ma, Hongrui; Walmsley, Harold; Cracknell, Roger [Shell Global Solutions (UK), Shell Research Centre Thornton, P. O. Box 1, Chester, CH1 3SH (United Kingdom); Stevens, Robert; Richardson, David; Fu, Huiyu; Wallace, Stan [Jaguar Cars, Engineering Centre, Abbey Road, Whitley, Coventry, CV3 4LF (United Kingdom)

2010-10-15

A study of in-cylinder fuel-air mixing distributions in a firing gasoline-direct-injection engine is reported using planar laser-induced fluorescence (PLIF) imaging. A multi-component fuel synthesised from three pairs of components chosen to simulate light, medium and heavy fractions was seeded with one of three tracers, each chosen to co-evaporate with and thus follow one of the fractions, in order to account for differential volatility of such components in typical gasoline fuels. In order to make quantitative measurements of fuel-air ratio from PLIF images, initial calibration was by recording PLIF images of homogeneous fuel-air mixtures under similar conditions of in-cylinder temperature and pressure using a re-circulation loop and a motored engine. This calibration method was found to be affected by two significant factors. Firstly, calibration was affected by variation of signal collection efficiency arising from build-up of absorbing deposits on the windows during firing cycles, which are not present under motored conditions. Secondly, the effects of residual exhaust gas present in the firing engine were not accounted for using a calibration loop with a motored engine. In order to account for these factors a novel method of PLIF calibration is presented whereby 'bookend' calibration measurements for each tracer separately are performed under firing conditions, utilising injection into a large upstream heated plenum to promote the formation of homogeneous in-cylinder mixtures. These calibration datasets contain sufficient information to not only characterise the quantum efficiency of each tracer during a typical engine cycle, but also monitor imaging efficiency, and, importantly, account for the impact of exhaust gas residuals (EGR). By use of this method EGR is identified as a significant factor in quantitative PLIF for fuel mixing diagnostics in firing engines. The effects of cyclic variation in fuel concentration on burn rate are analysed for

Characteristic Evaluation on the Cooling Performance of an Electrical Air Conditioning System Using R744 for a Fuel Cell Electric Vehicle

Directory of Open Access Journals (Sweden)

Moo-Yeon Lee

2012-05-01

Full Text Available The objective of this study was to investigate the cooling performance characteristics of an electrical air conditioning system using R744 as an alternative of R-134a for a fuel cell electric vehicle. In order to analyze the cooling performance characteristics of the air conditioning system using R744 for a fuel cell electric vehicle, an electrical air conditioning system using R744 was developed and tested under various operating conditions according to both inlet air conditions of the gas cooler and evaporator and compressor speed. The cooling capacity and coefficient of performance (COP forcooling of the tested air conditioning system were up to 6.4 kW and 2.5, respectively. In addition, the electrical air conditioning system with R744 using an inverter driven compressor showed better performance than the conventional air conditioning system with R-134a under the same operating conditions. The observed cooling performance of the developed electrical air conditioning system was found to be sufficient for cooling loads under various real driving conditions for a fuel cell electric vehicle.

Effects of operating conditions and fuel properties on emission performance and combustion efficiency of a swirling fluidized-bed combustor fired with a biomass fuel

International Nuclear Information System (INIS)

Kuprianov, Vladimir I.; Kaewklum, Rachadaporn; Chakritthakul, Songpol

2011-01-01

This work reports an experimental study on firing 80 kg/h rice husk in a swirling fluidized-bed combustor (SFBC) using an annular air distributor as the swirl generator. Two NO x emission control techniques were investigated in this work: (1) air staging of the combustion process, and (2) firing rice husk as moisturized fuel. In the first test series for the air-staged combustion, CO, NO and C x H y emissions and combustion efficiency were determined for burning 'as-received' rice husk at fixed excess air of 40%, while secondary-to-primary air ratio (SA/PA) was ranged from 0.26 to 0.75. The effects of SA/PA on CO and NO emissions from the combustor were found to be quite weak, whereas C x H y emissions exhibited an apparent influence of air staging. In the second test series, rice husks with the fuel-moisture content of 8.4% to 35% were fired at excess air varied from 20% to 80%, while the flow rate of secondary air was fixed. Radial and axial temperature and gas concentration (O 2 , CO, NO) profiles in the reactor, as well as CO and NO emissions, are discussed for the selected operating conditions. The temperature and gas concentration profiles for variable fuel quality exhibited significant effects of both fuel-moisture and excess air. As revealed by experimental results, the emission of NO from this SFBC can be substantially reduced through moisturizing rice husk, while CO is effectively mitigated by injection of secondary air into the bed splash zone, resulting in a rather low emission of CO and high (over 99%) combustion efficiency of the combustor for the ranges of operating conditions and fuel properties.

Studying the effect of compression ratio on an engine fueled with waste oil produced biodiesel/diesel fuel

Directory of Open Access Journals (Sweden)

Mohammed EL_Kassaby

2013-03-01

Full Text Available Wasted cooking oil from restaurants was used to produce neat (pure biodiesel through transesterification, and then used to prepare biodiesel/diesel blends. The effect of blending ratio and compression ratio on a diesel engine performance has been investigated. Emission and combustion characteristics was studded when the engine operated using the different blends (B10, B20, B30, and B50 and normal diesel fuel (B0 as well as when varying the compression ratio from 14 to 16 to 18. The result shows that the engine torque for all blends increases as the compression ratio increases. The bsfc for all blends decreases as the compression ratio increases and at all compression ratios bsfc remains higher for the higher blends as the biodiesel percent increase. The change of compression ratio from 14 to 18 resulted in, 18.39%, 27.48%, 18.5%, and 19.82% increase in brake thermal efficiency in case of B10, B20, B30, and B50 respectively. On an average, the CO2 emission increased by 14.28%, the HC emission reduced by 52%, CO emission reduced by 37.5% and NOx emission increased by 36.84% when compression ratio was increased from 14 to 18. In spite of the slightly higher viscosity and lower volatility of biodiesel, the ignition delay seems to be lower for biodiesel than for diesel. On average, the delay period decreased by 13.95% when compression ratio was increased from 14 to 18. From this study, increasing the compression ratio had more benefits with biodiesel than that with pure diesel.

Experimental investigation of particle emissions under different EGR ratios on a diesel engine fueled by blends of diesel/gasoline/n-butanol

International Nuclear Information System (INIS)

Huang, Haozhong; Liu, Qingsheng; Wang, Qingxin; Zhou, Chengzhong; Mo, Chunlan; Wang, Xueqiang

2016-01-01

Highlights: • The effects of EGR and blend fuels on particulate emission were studied in CI engine. • EGR ⩽ 20%, gasoline or n-butanol increases total particulate number concentration. • EGR ⩾ 30%, gasoline or n-butanol reduces total particulate number concentration. • As EGR ratio increased, the particulate mass concentrations of four fuels increased. • Gasoline or n-butanol increases the ratio of sub-25 nm particles number concentration. - Abstract: The particle emission characteristics of a high-pressure common-rail engine under different EGR conditions were investigated, using pure diesel (D100), diesel/gasoline (with a volume ratio of 70:30, D70G30), diesel/n-butanol (with a volume ratio of 70:30, D70B30) and diesel/gasoline/n-butanol (with a volume ratio of 70:15:15, D70G15B15) for combustion. Our results show that, with increasing EGR ratios, the in-cylinder pressure peak decreases and the heat release is delayed for the combustion of each fuel. At an EGR ratio of 30%, the combustion pressure peaks of D70G30, D70B30, D70G15B15 and D100 have similar values; with an EGR ratio of 40%, the combustion pressure peaks and release rate peaks of D70G30 and D70G15B15 are both lower with respect to D100. For small and medium EGR ratios (⩽20%), after the addition of gasoline and/or n-butanol to the fuel, the total particle number concentration (TPNC) increases, while both the soot emissions and the average geometric size of particles decrease. At large EGR ratios (30% and 40%), the TPNC of D70B30, D70G15B15 and D70G20 compared to D100 are reduced by a maximum amount of 74.7%, 66.7% and 28.6%, respectively. As the EGR ratio increases, the total particle mass concentration increases gradually for all four fuels. Blending gasoline or/and n-butanol into diesel induces an increase in the number concentration of sub-25 nm particles (PN25) which may be harmful in terms of health. However, the PN25 decreases with increasing the EGR ratio for all the tested fuels

An experimental investigation into combustion and performance characteristics of an HCCI gasoline engine fueled with n-heptane, isopropanol and n-butanol fuel blends at different inlet air temperatures

International Nuclear Information System (INIS)

Uyumaz, Ahmet

2015-01-01

Highlights: • Combustion was retarded with the increase of the amount of isopropanol and n-butanol in the test fuels. • Combustion was advanced with the increase of air inlet temperature on HCCI combustion. • Isopropanol seems more suitable fuel due to controlling the HCCI combustion and preventing knocking. • Almost zero NO emissions were measured when alcohol used except for n-heptane and B20 test fuels. - Abstract: An experimental study was conducted in a single cylinder, four stroke port injection Ricardo Hydra test engine in order to determine the effects of pure n-heptane, the blends of n-heptane and n-butanol fuels B20, B30, B40 (including 20%, 30%, 40% n-butanol and 80%, 70%, 60% n-heptane by vol. respectively) and the blends of n-heptane and isopropanol fuels P20, P30, P40 (including 20%, 30%, 40% isopropanol and 80%, 70%, 60% n-heptane by vol. respectively) on HCCI combustion. Combustion and performance characteristics of n-heptane, n-butanol and isopropanol were investigated at constant engine speed of 1500 rpm and λ = 2 in a HCCI engine. The effects of inlet air temperature were also examined on HCCI combustion. The test results showed that the start of combustion was advanced with the increasing of inlet air temperature for all test fuels. Start of combustion delayed with increasing percentage of n-butanol and isopropanol in the test fuels. Knocking combustion was seen with B20 and n-heptane test fuels. Minimum combustion duration was observed in case of using B40. Almost zero NO emissions were measured with test fuels apart from n-heptane and B20. The test results also showed that CO and HC emissions decreased with the increase of inlet air temperature for all test fuels. Isopropanol showed stronger resistance for knocking compared to n-butanol in HCCI combustion due to its higher octane number. It was determined that n-butanol was more advantageous according to isopropanol as thermal efficiency. As a result it was found that the HCCI

Effective sulfur and energy recovery from hydrogen sulfide through incorporating an air-cathode fuel cell into chelated-iron process.

Science.gov (United States)

Sun, Min; Song, Wei; Zhai, Lin-Feng; Cui, Yu-Zhi

2013-12-15

The chelated-iron process is among the most promising techniques for the hydrogen sulfide (H2S) removal due to its double advantage of waste minimization and resource recovery. However, this technology has encountered the problem of chelate degradation which made it difficult to ensure reliable and economical operation. This work aims to develop a novel fuel-cell-assisted chelated-iron process which employs an air-cathode fuel cell for the catalyst regeneration. By using such a process, sulfur and electricity were effectively recovered from H2S and the problem of chelate degradation was well controlled. Experiment on a synthetic sulfide solution showed the fuel-cell-assisted chelated-iron process could maintain high sulfur recovery efficiencies generally above 90.0%. The EDTA was preferable to NTA as the chelating agent for electricity generation, given the Coulombic efficiencies (CEs) of 17.8 ± 0.5% to 75.1 ± 0.5% for the EDTA-chelated process versus 9.6 ± 0.8% to 51.1 ± 2.7% for the NTA-chelated process in the pH range of 4.0-10.0. The Fe (III)/S(2-) ratio exhibited notable influence on the electricity generation, with the CEs improved by more than 25% as the Fe (III)/S(2-) molar ratio increased from 2.5:1 to 3.5:1. Application of this novel process in treating a H2S-containing biogas stream achieved 99% of H2S removal efficiency, 78% of sulfur recovery efficiency, and 78.6% of energy recovery efficiency, suggesting the fuel-cell-assisted chelated-iron process was effective to remove the H2S from gas streams with favorable sulfur and energy recovery efficiencies. Copyright © 2013 Elsevier B.V. All rights reserved.

Comparison of emission inventory and ambient concentration ratios of CO, NMOG, and NOx in California South Coast Air Basin

International Nuclear Information System (INIS)

Fujita, E.M.; Croes, B.E.; Bennett, C.L.; Lawson, D.R.; Lurmann, F.W.; Main, H.H.

1992-01-01

In the present study, the author performed a top-down validation of the reactive organic gas and carbon monoxide emission inventories for California's South Coast Air Basin by comparing speciation profiles for nonmethane organic gases (NMOG) and ratios of CO/NO x and NMOG/NO x derived from early-morning (0700 to 0800) ambient measurements taken during the 1987 Southern California Air Quality Study with the corresponding ratios and speciation profiles derived from day-specific, hourly, gridded emission inventories. Twenty separate comparisons were considered for each ratio, each representing a different combination of season, emission category, and spatial and temporal averaging of emissions. It was determined that the most appropriate comparison in summer was ambient pollutant ratios with ratios derived from morning on-road motrovehicle emission inventories, and in the fall, ambient ratios with ratios derived from overnight on-road motor vehicle emission inventories with some contribution from overnight stationary-source NO x emission inventories. From these comparisons, the ambient CO/CO x and NMOG/NO x ratios are about 1.5 and 2 to 2.5 times higher, respectively, than the corresponding inventory ratios. On the assumption that inventories of NO x emissions are reasonably correct, these results indicate that on-road motor vehicle CO and NMOG emissions are significantly underestimated. Comparisons of measured CO, NMOG, and NO x concentrations and CO/NO x and NMOG/NO x ratios with air quality model predictions obtained by the California Air Resources Board show similar differences

Stress Calculation of a TRISO Coated Particle Fuel by Using a Poisson's Ratio in Creep Condition

International Nuclear Information System (INIS)

Cho, Moon-Sung; Kim, Y. M.; Lee, Y. W.; Jeong, K. C.; Kim, Y. K.; Oh, S. C.; Kim, W. K.

2007-01-01

KAERI, which has been carrying out the Korean VHTR (Very High Temperature modular gas cooled Reactor) project since 2004, has been developing a performance analysis code for the TRISO coated particle fuel named COPA (COated Particle fuel Analysis). COPA predicts temperatures, stresses, a fission gas release and failure probabilities of a coated particle fuel in normal operating conditions. KAERI, on the other hand, is developing an ABAQUS based finite element(FE) model to cover the non-linear behaviors of a coated particle fuel such as cracking or debonding of the TRISO coating layers. Using the ABAQUS based FE model, verification calculations were carried out for the IAEA CRP-6 benchmark problems involving creep, swelling, and pressure. However, in this model the Poisson's ratio for elastic solution was used for creep strain calculation. In this study, an improvement is made for the ABAQUS based finite element model by using the Poisson's ratio in creep condition for the calculation of the creep strain rate. As a direct input of the coefficient in a creep condition is impossible, a user subroutine for the ABAQUS solution is prepared in FORTRAN for use in the calculations of the creep strain of the coating layers in the radial and hoop directions of the spherical fuel. This paper shows the calculation results of a TRISO coated particle fuel subject to an irradiation condition assumed as in the Miller's publication in comparison with the results obtained from the old FE model used in the CRP-6 benchmark calculations

Air humidity and water pressure effects on the performance of air-cathode microbial fuel cell cathodes

KAUST Repository

Ahn, Yongtae

2014-02-01

To better understand how air cathode performance is affected by air humidification, microbial fuel cells were operated under different humidity conditions or water pressure conditions. Maximum power density decreased from 1130 ± 30 mW m-2 with dry air to 980 ± 80 mW m -2 with water-saturated air. When the cathode was exposed to higher water pressures by placing the cathode in a horizontal position, with the cathode oriented so it was on the reactor bottom, power was reduced for both with dry (1030 ± 130 mW m-2) and water-saturated (390 ± 190 mW m-2) air. Decreased performance was partly due to water flooding of the catalyst, which would hinder oxygen diffusion to the catalyst. However, drying used cathodes did not improve performance in electrochemical tests. Soaking the cathode in a weak acid solution, but not deionized water, mostly restored performance (960 ± 60 mW m-2), suggesting that there was salt precipitation in the cathode that was enhanced by higher relative humidity or water pressure. These results showed that cathode performance could be adversely affected by both flooding and the subsequent salt precipitation, and therefore control of air humidity and water pressure may need to be considered for long-term MFC operation. © 2013 Elsevier B.V. All rights reserved.

Multiple Threats to Child Health from Fossil Fuel Combustion: Impacts of Air Pollution and Climate Change

Science.gov (United States)

Perera, Frederica P.

2016-01-01

Background: Approaches to estimating and addressing the risk to children from fossil fuel combustion have been fragmented, tending to focus either on the toxic air emissions or on climate change. Yet developing children, and especially poor children, now bear a disproportionate burden of disease from both environmental pollution and climate change due to fossil fuel combustion. Objective: This commentary summarizes the robust scientific evidence regarding the multiple current and projected health impacts of fossil fuel combustion on the young to make the case for a holistic, child-centered energy and climate policy that addresses the full array of physical and psychosocial stressors resulting from fossil fuel pollution. Discussion: The data summarized here show that by sharply reducing our dependence on fossil fuels we would achieve highly significant health and economic benefits for our children and their future. These benefits would occur immediately and also play out over the life course and potentially across generations. Conclusion: Going beyond the powerful scientific and economic arguments for urgent action to reduce the burning of fossil fuels is the strong moral imperative to protect our most vulnerable populations. Citation: Perera FP. 2017. Multiple threats to child health from fossil fuel combustion: impacts of air pollution and climate change. Environ Health Perspect 125:141–148; http://dx.doi.org/10.1289/EHP299 PMID:27323709

Nitric oxide density measurements in air and air/fuel nanosecond pulse discharges by laser induced fluorescence

International Nuclear Information System (INIS)

Uddi, M; Jiang, N; Adamovich, I V; Lempert, W R

2009-01-01

Laser induced fluorescence is used to measure absolute nitric oxide concentrations in air, methane-air and ethylene-air non-equilibrium plasmas, as a function of time after initiation of a single pulse, 20 kV peak voltage, 25 ns pulse duration discharge. A mixture of NO and nitrogen with known composition (4.18 ppm NO) is used for calibration. Peak NO density in air at 60 Torr, after a single pulse, is ∼8 x 10 12 cm -3 (∼4.14 ppm) occurring at ∼250 μs after the pulse, with decay time of ∼16.5 ms. Peak NO atom mole fraction in a methane-air mixture with equivalence ratio of ψ = 0.5 is found to be approximately equal to that in air, with approximately the same rise and decay rate. In an ethylene-air mixture (also with equivalence ratio of ψ = 0.5), the rise and decay times are comparable to air and methane-air, but the peak NO concentration is reduced by a factor of approximately 2.5. Spontaneous emission measurements show that excited electronic states N 2 (C 3 Π) and NO(A 2 Σ) in air at P = 60 Torr decay within ∼20 ns and ∼1 μs, respectively. Kinetic modelling calculations incorporating air plasma kinetics complemented with the GRI Mech 3.0 hydrocarbon oxidation mechanism are compared with the experimental data using three different NO production mechanisms. It is found that NO concentration rise after the discharge pulse is much faster than predicted by Zel'dovich mechanism reactions, by two orders of magnitude, but much slower compared with reactions of electronically excited nitrogen atoms and molecules, also by two orders of magnitude. It is concluded that processes involving long lifetime (∼100 μs) metastable states, such as N 2 (X 1 Σ,v) and O 2 (b 1 Σ), formed by quenching of the metastable N 2 (A 3 Σ) state by ground electronic state O 2 , may play a dominant role in NO formation. NO decay, in all cases, is found to be dominated by the reverse Zel'dovich reaction, NO + O → N + O 2 , as well as by conversion into NO 2 in a reaction

Nitric oxide density measurements in air and air/fuel nanosecond pulse discharges by laser induced fluorescence

Science.gov (United States)

Uddi, M.; Jiang, N.; Adamovich, I. V.; Lempert, W. R.

2009-04-01

Laser induced fluorescence is used to measure absolute nitric oxide concentrations in air, methane-air and ethylene-air non-equilibrium plasmas, as a function of time after initiation of a single pulse, 20 kV peak voltage, 25 ns pulse duration discharge. A mixture of NO and nitrogen with known composition (4.18 ppm NO) is used for calibration. Peak NO density in air at 60 Torr, after a single pulse, is ~8 × 1012 cm-3 (~4.14 ppm) occurring at ~250 µs after the pulse, with decay time of ~16.5 ms. Peak NO atom mole fraction in a methane-air mixture with equivalence ratio of phiv = 0.5 is found to be approximately equal to that in air, with approximately the same rise and decay rate. In an ethylene-air mixture (also with equivalence ratio of phiv = 0.5), the rise and decay times are comparable to air and methane-air, but the peak NO concentration is reduced by a factor of approximately 2.5. Spontaneous emission measurements show that excited electronic states N2(C 3Π) and NO(A 2Σ) in air at P = 60 Torr decay within ~20 ns and ~1 µs, respectively. Kinetic modelling calculations incorporating air plasma kinetics complemented with the GRI Mech 3.0 hydrocarbon oxidation mechanism are compared with the experimental data using three different NO production mechanisms. It is found that NO concentration rise after the discharge pulse is much faster than predicted by Zel'dovich mechanism reactions, by two orders of magnitude, but much slower compared with reactions of electronically excited nitrogen atoms and molecules, also by two orders of magnitude. It is concluded that processes involving long lifetime (~100 µs) metastable states, such as N2(X 1Σ,v) and O2(b 1Σ), formed by quenching of the metastable N2(A 3Σ) state by ground electronic state O2, may play a dominant role in NO formation. NO decay, in all cases, is found to be dominated by the reverse Zel'dovich reaction, NO + O → N + O2, as well as by conversion into NO2 in a reaction of NO with ozone.

An Investigation of Fuel Mixing and Reaction in a CH4/Syngas/Air Premixed Impinging Flame with Varied H2/CO Proportion

Directory of Open Access Journals (Sweden)

Chih-Pin Chiu

2017-07-01

Full Text Available For industrial applications, we propose a concept of clean and efficient combustion through burning syngas on an impinging burner. We performed experimental measurements of particle image velocimetry, OH radical (OH* chemiluminescence, flame temperature, and CO emission to examine the fuel mixing and reaction of premixed impinging flames of CH4/syngas/air with H2/CO in varied proportions. The velocity distribution of the combustion flow field showed that a deceleration area in the main flow formed through the mutual impingement of two jet flows, which enhanced the mixing of fuel and air because of an increased momentum transfer. The deceleration area expanded with an increased CO proportion, which indicated that the mixing of fuel and air also increased with the increased CO proportion. Our examination of the OH* chemiluminescence demonstrated that its intensity increased with increased CO proportion, which showed that the reaction between fuel and air accordingly increased. CO provided in the syngas hence participated readily in the reaction of the CH4/syngas/air premixed impinging flames when the syngas contained CO in a large proportion. Although the volume flow rate of the provided CO quadrupled, the CO emission increased by only 12% to 15%. The results of this work are useful to improve the feasibility of fuel-injection systems using syngas as an alternative fuel.

Oxygen-to-metal ratio control during fabrication of mixed oxide fast breeder reactor fuel pellets

International Nuclear Information System (INIS)

Rasmussen, D.E.; Benecke, M.W.; Jentzen, W.R.; McCord, R.B.

1979-05-01

Oxygen-to-metal ratio (O/M) of mixed oxide fuel pellets can be controlled during fabrication by proper selection of binder (type and content) and sintering conditions. Sintering condition adjustments involved the passing of Ar--8% H 2 sintering gas across a cryostat ice bath controlled to temperatures ranging from -5 to -60 0 C to control as-sintered pellet O/M ratio. As-sintered fuel pellet O/M decreased with increasing Sterotex binder and PuO 2 concentrations, increasing sintering temperature, and decreasing sintering gas dew point. Approximate relationships between Sterotex binder level and O/M were established for PuO 2 --UO 2 and PuO 2 --ThO 2 fuels. O/M was relatively insensitive to Carbowax binder concentration. Several methods of increasing O/M using post-sintering pellet heat treatments were demonstrated, with the most reliable being a two-step process of first raising the O/M to 2.00 (stoichiometric) at 650 0 C in Ar--8% H 2 bubbled through H 2 O, followed by hydrogen reduction to specification O/M in oxygen-gettered Ar-8% H 2 at temperatures ranging from 1200 to 1690 0 C

Evaluating the Environmental Performance of the U.S. Next Generation Air Transportation System

Science.gov (United States)

Graham, Michael; Augustine, Stephen; Ermatinger, Christopher; Difelici, John; Thompson, Terence R.; Marcolini, Michael A.; Creedon, Jeremiah F.

2009-01-01

The environmental impacts of several possible U.S. Next Generation Air Transportation scenarios have been quantitatively evaluated for noise, air-quality, fuel-efficiency, and CO2 impacts. Three principal findings have emerged. (1) 2025 traffic levels about 30% higher than 2006 are obtained by increasing traffic according to FAA projections while also limiting traffic at each airport using reasonable ratios of demand to capacity. NextGen operational capabilities alone enable attainment of an additional 10-15% more flights beyond that 2025 baseline level with negligible additional noise, air-quality, and fuel-efficiency impacts. (2) The addition of advanced engine and airframe technologies provides substantial additional reductions in noise and air-quality impacts, and further improves fuel efficiency. 2025 environmental goals based on projected system-wide improvement rates of about 1% per year for noise and fuel-efficiency (an air-quality goal is not yet formulated) are achieved using this new vehicle technology. (3) Overall air-transport "product", as measured by total flown distance or total payload distance, increases by about 50% relative to 2006, but total fuel consumption and CO2 production increase by only about 40% using NextGen operational capabilities. With the addition of advanced engine/airframe technologies, the increase in total fuel consumption and CO2 production can be reduced to about 30%.

Disease burden due to biomass cooking-fuel-related household air pollution among women in India.

Science.gov (United States)

Sehgal, Meena; Rizwan, Suliankatchi Abdulkader; Krishnan, Anand

2014-01-01

Household air pollution (HAP) due to biomass cooking fuel use is an important risk factor for a range of diseases, especially among adult women who are primary cooks, in India. About 80% of rural households in India use biomass fuel for cooking. The aim of this study is to estimate the attributable cases (AC) for four major diseases/conditions associated with biomass cooking fuel use among adult Indian women. We used the population attributable fraction (PAF) method to calculate the AC of chronic bronchitis, tuberculosis (TB), cataract, and stillbirths due to exposure to biomass cooking fuel. A number of data sources were accessed to obtain population totals and disease prevalence rates. A meta-analysis was conducted to obtain adjusted pooled odds ratios (ORs) for strength of association. Using this, PAF and AC were calculated using a standard formula. Results were presented as number of AC and 95% confidence intervals (CI). The fixed effects pooled OR obtained from the meta-analysis were 2.37 (95% CI: 1.59, 3.54) for chronic bronchitis, 2.33 (1.65, 3.28) for TB, 2.16 (1.42, 3.26) for cataract, and 1.26 (1.12, 1.43) for stillbirths. PAF varied across conditions being maximum (53%) for chronic bronchitis in rural areas and least (1%) for cataract in older age and urban areas. About 2.4 (95% CI: 1.4, 3.1) of 5.6 m cases of chronic bronchitis, 0.3 (0.2, 0.4) of 0.76 m cases of TB, 5.0 (2.8, 6.7) of 51.4 m cases of cataract among adult Indian women and 0.02 (0.01, 0.03) of 0.15 m stillbirths across India are attributable to HAP due to biomass cooking fuel. These estimates should be cautiously interpreted in the light of limitations discussed which relate to exposure assessment, exposure characterization, and age-specific prevalence of disease. HAP due to biomass fuel has diverse and major impacts on women's health in India. Although challenging, incorporating the agenda of universal clean fuel access or cleaner technology within the broader framework of rural

Market penetration scenarios for fuel cell vehicles

Energy Technology Data Exchange (ETDEWEB)

Thomas, C.E.; James, B.D.; Lomax, F.D. Jr. [Directed Technologies, Inc., Arlington, VA (United States)

1997-12-31

Fuel cell vehicles may create the first mass market for hydrogen as an energy carrier. Directed Technologies, Inc., working with the US Department of Energy hydrogen systems analysis team, has developed a time-dependent computer market penetration model. This model estimates the number of fuel cell vehicles that would be purchased over time as a function of their cost and the cost of hydrogen relative to the costs of competing vehicles and fuels. The model then calculates the return on investment for fuel cell vehicle manufacturers and hydrogen fuel suppliers. The model also projects the benefit/cost ratio for government--the ratio of societal benefits such as reduced oil consumption, reduced urban air pollution and reduced greenhouse gas emissions to the government cost for assisting the development of hydrogen energy and fuel cell vehicle technologies. The purpose of this model is to assist industry and government in choosing the best investment strategies to achieve significant return on investment and to maximize benefit/cost ratios. The model can illustrate trends and highlight the sensitivity of market penetration to various parameters such as fuel cell efficiency, cost, weight, and hydrogen cost. It can also illustrate the potential benefits of successful R and D and early demonstration projects. Results will be shown comparing the market penetration and return on investment estimates for direct hydrogen fuel cell vehicles compared to fuel cell vehicles with onboard fuel processors including methanol steam reformers and gasoline partial oxidation systems. Other alternative fueled vehicles including natural gas hybrids, direct injection diesels and hydrogen-powered internal combustion hybrid vehicles will also be analyzed.

Dual fuel mode operation in diesel engines using renewable fuels: Rubber seed oil and coir-pith producer gas

Energy Technology Data Exchange (ETDEWEB)

Ramadhas, A.S.; Jayaraj, S.; Muraleedharan, C. [Department of Mechanical Engineering, National Institute of Technology Calicut, Calicut-673601 (India)

2008-09-15

Partial combustion of biomass in the gasifier generates producer gas that can be used as supplementary or sole fuel for internal combustion engines. Dual fuel mode operation using coir-pith derived producer gas and rubber seed oil as pilot fuel was analyzed for various producer gas-air flow ratios and at different load conditions. The engine is experimentally optimized with respect to maximum pilot fuel savings in the dual fuel mode operation. The performance and emission characteristics of the dual fuel engine are compared with that of diesel engine at different load conditions. Specific energy consumption in the dual-fuel mode of operation with oil-coir-pith operation is found to be in the higher side at all load conditions. Exhaust emission was found to be higher in the case of dual fuel mode of operation as compared to neat diesel/oil operation. Engine performance characteristics are inferior in fully renewable fueled engine operation but it suitable for stationary engine application, particularly power generation. (author)

Roots Air Management System with Integrated Expander

Energy Technology Data Exchange (ETDEWEB)

Stretch, Dale [Eaton Corporation, Menomonee Falls, WI (United States); Wright, Brad [Eaton Corporation, Menomonee Falls, WI (United States); Fortini, Matt [Eaton Corporation, Menomonee Falls, WI (United States); Fink, Neal [Ballard Power Systems, Burnaby, BC (Canada); Ramadan, Bassem [Kettering Univ., Flint, MI (United States); Eybergen, William [Eaton Corporation, Menomonee Falls, WI (United States)

2016-07-06

PEM fuel cells remain an emerging technology in the vehicle market with several cost and reliability challenges that must be overcome in order to increase market penetration and acceptance. The DOE has identified the lack of a cost effective, reliable, and efficient air supply system that meets the operational requirements of a pressurized PEM 80kW fuel cell as one of the major technological barriers that must be overcome. This project leveraged Roots positive displacement development advancements and demonstrated an efficient and low cost fuel cell air management system. Eaton built upon its P-Series Roots positive displacement design and shifted the peak efficiency making it ideal for use on an 80kW PEM stack. Advantages to this solution include: • Lower speed of the Roots device eliminates complex air bearings present on other systems. • Broad efficiency map of Roots based systems provides an overall higher drive cycle fuel economy. • Core Roots technology has been developed and validated for other transportation applications. Eaton modified their novel R340 Twin Vortices Series (TVS) Roots-type supercharger for this application. The TVS delivers more power and better fuel economy in a smaller package as compared to other supercharger technologies. By properly matching the helix angle with the rotor’s physical aspect ratio, the supercharger’s peak efficiency can be moved to the operating range where it is most beneficial for the application. The compressor was designed to meet the 90 g/s flow at a pressure ratio of 2.5, similar in design to the P-Series 340. A net shape plastic expander housing with integrated motor and compressor was developed to significantly reduce the cost of the system. This integrated design reduced part count by incorporating an overhung expander and motor rotors into the design such that only four bearings and two shafts were utilized.

Air quality impacts of increased use of indigenous fuels for power generation in the Philippines

International Nuclear Information System (INIS)

Orbeta, E.M.

2003-01-01

The 2002-2011 Philippine Energy plan promotes the restructuring of its troubled power sector to ensure efficiency, reliability in supply and competitive electricity pricing. In particular, the plan promotes the use of indigenous fuels to increase self-sufficiency and reduce dependence on imported fuels. However, the indigenous fuel that will replace imported oil includes coal (a highly polluting energy source) and geothermal power. This paper assessed the environmental and health impacts associated with the development of coal and geothermal energy in the Philippines. It was determined that from 2001 to 2011, the development of geothermal energy could result in less air pollution than a scenario in which only current energy sources are developed. However, the expected increase in generating capacity in the Philippines will result in a general increase in air pollution levels. Local coal is singled out as the primary polluting energy source. Several pollution reduction initiatives were recommended, including improved pollution monitoring and energy efficiency measures. 18 refs., 21 tabs., 4 figs., 8 appendices

Commuters’ Exposure to Particulate Matter Air Pollution Is Affected by Mode of Transport, Fuel Type, and Route

Science.gov (United States)

Zuurbier, Moniek; Hoek, Gerard; Oldenwening, Marieke; Lenters, Virissa; Meliefste, Kees; van den Hazel, Peter; Brunekreef, Bert

2010-01-01

Background Commuters are exposed to high concentrations of air pollutants, but little quantitative information is currently available on differences in exposure between different modes of transport, routes, and fuel types. Objectives The aim of our study was to assess differences in commuters’ exposure to traffic-related air pollution related to transport mode, route, and fuel type. Methods We measured particle number counts (PNCs) and concentrations of PM2.5 (particulate matter ≤ 2.5 μm in aerodynamic diameter), PM10, and soot between June 2007 and June 2008 on 47 weekdays, from 0800 to 1000 hours, in diesel and electric buses, gasoline- and diesel-fueled cars, and along two bicycle routes with different traffic intensities in Arnhem, the Netherlands. In addition, each-day measurements were taken at an urban background location. Results We found that median PNC exposures were highest in diesel buses (38,500 particles/cm3) and for cyclists along the high-traffic intensity route (46,600 particles/cm3) and lowest in electric buses (29,200 particles/cm3). Median PM10 exposure was highest from diesel buses (47 μg/m3) and lowest along the high- and low-traffic bicycle routes (39 and 37 μg/m3). The median soot exposure was highest in gasoline-fueled cars (9.0 × 10−5/m), diesel cars (7.9 × 10−5/m), and diesel buses (7.4 × 10−5/m) and lowest along the low-traffic bicycle route (4.9 × 10−5/m). Because the minute ventilation (volume of air per minute) of cyclists, which we estimated from measured heart rates, was twice the minute ventilation of car and bus passengers, we calculated that the inhaled air pollution doses were highest for cyclists. With the exception of PM10, we found that inhaled air pollution doses were lowest for electric bus passengers. Conclusions Commuters’ rush hour exposures were significantly influenced by mode of transport, route, and fuel type. PMID:20185385

Numerical investigation of combustion phenomena in pulse detonation engine with different fuels

Science.gov (United States)

Alam, Noor; Sharma, K. K.; Pandey, K. M.

2018-05-01

The effects of different fuel-air mixture on the cyclic operation of pulse detonation engine (PDE) are numerically investigated. The present simulation is to be consider 1200 mm long straight tube combustor channel and 60 mm internal diameter, and filled with stoichiometric ethane-air and ethylene-air (C2H6-air & C2H4) fuel mixture at atmospheric pressure and temperature of 0.1 MPa and 300 K respectively. The obstacles of blockage ratio (BR) 0.5 and having 60 mm spacing among them are allocated inside the combustor tube. There are realizable k-ɛ turbulence model used to analyze characteristic of combustion flame. The objective of present simulation is to analyze the variation in combustion mechanism for two different fuels with one-step reduced chemical reaction model. The obstacles were creating perturbation inside the PDE tube. Therefore, flame surface area increases and reduces deflagration-to-detonation transition (DDT) run-up length.

Premixer assembly for mixing air and fuel for combustion

Science.gov (United States)

York, William David; Johnson, Thomas Edward; Keener, Christopher Paul

2016-12-13

A premixer assembly for mixing air and fuel for combustion includes a plurality of tubes disposed at a head end of a combustor assembly. Also included is a tube of the plurality of tubes, the tube including an inlet end and an outlet end. Further included is at least one non-circular portion of the tube extending along a length of the tube, the at least one non-circular portion having a non-circular cross-section, and the tube having a substantially constant cross-sectional area along its length

Bi-fuel System - Gasoline/LPG in A Used 4-Stroke Motorcycle - Fuel Injection Type

Science.gov (United States)

Suthisripok, Tongchit; Phusakol, Nachaphat; Sawetkittirut, Nuttapol

2017-10-01

Bi-fuel-Gasoline/LPG system has been effectively and efficiently used in gasoline vehicles with less pollutants emission. The motorcycle tested was a used Honda AirBlade i110 - fuel injection type. A 3-litre LPG storage tank, an electronic fuel control unit, a 1-mm LPG injector and a regulator were securely installed. The converted motorcycle can be started with either gasoline or LPG. The safety relief valve was set below 48 kPa and over 110 kPa. The motorcycle was tuned at the relative rich air-fuel ratio (λ) of 0.85-0.90 to attain the best power output. From dynamometer tests over the speed range of 65-100 km/h, the average power output when fuelling LPG was 5.16 hp; dropped 3.9% from the use of gasoline91. The average LPG consumption rate from the city road test at the average speed of 60 km/h was 40.1 km/l, about 17.7% more. This corresponded to lower LPG’s energy density of about 16.2%. In emission, the CO and HC concentrations were 44.4% and 26.5% lower. Once a standard gas equipment set with ECU and LPG injector were securely installed and the engine was properly tuned up to suit LPG’s characteristics, the converted bi-fuel motorcycle offers efficiently, safely and economically performance with environmental friendly emission.

The ratio of long-lived to short-lived radon-222 progeny concentrations in ground-level air

International Nuclear Information System (INIS)

Hoetzl, H.; Winkler, R.

1996-01-01

The ratio of 210 Pb air concentration to the short-lived radon ( 222 Rn) decay products concentration at ground level was investigated at a semi-rural location 10 km north of Munich, south Germany, for a period of 11 years (1982-1992). The average ratio from 132 monthly mean values has been found to be (7.5±2.2) x 10 -5 (arithmetic mean±S.D.). While the time series of the short-lived radon daughter concentration exhibit a distinct seasonal pattern with maxima mostly in October of each year, the course of 210 Pb air concentration is characterized by high values from October through February. Consequently, high ratios of 210 Pb to short-lived decay product concentration are often observed in the winter months of December-February. To study the influence of meteorological conditions on this behaviour, 210 Pb and 214 Pb concentrations were measured on a short-term basis with sampling intervals of 2-3 days from October 1991 to November 1992. The air concentrations obtained within those intervals were then correlated with actual meteorological parameters. On the base of this investigation the seasonal behaviour can essentially be explained by the more frequent inversion weather conditions in winter than in the summer months. At the same location, the average ratio of 210 Po to 210 Pb concentration in ground level air has been found to be 0.079 from 459 weakly mean values between 1976 and 1985. Hence, the corresponding average ratios of the short-lived radon daughters (EEC) to 210 Pb and 210 Po, were 1:7.5x10 -5 and 1:0.6 x 10 -5 , respectively

Power, heat and chilliness with natural gas - fuel cells and air conditioning

International Nuclear Information System (INIS)

Krein, Stephan; Ruehling, Karin

1999-01-01

A new and innovative concept of the supply with power, heat and chilliness will realise in the new Malteser-hospital in Kamenz. The core of this demonstration-plant are a fuel cell, an adsorption cooling machine as well as multi-solar collectors. The fuel cell has two goals. Primary it produces power for the own demand. The selected dimension guarantees, that the power will consume nearly continuously. Secondly the produced heat of the fuel cell (and the solar-heat too) will use for heating and preparation of warm water. In the summer, the heat will use for the adsorption cooling machine, which produces chilliness for air-conditioning. The advantage in the face of common concepts of combining power and heat is the high-efficiently use of the fuel-energy for electric power generation on the one hand. Fuel cells work with high efficiency also at partial load. On the other hand, with the adsorption cooling machine the produced heat of fuel cell and multi-solar collectors can be used also in the summer. First experiences with this concept show, that an optimised co-operation of the components with an adaptive, self-learning control system based on the weather forecast as well as various storages for heat and chilliness can be achieve. A continuously operation, high fuel utilisation and reduced environmental pollution can be demonstrated. (author)

Numerical simulations of the industrial circulating fluidized bed boiler under air- and oxy-fuel combustion

International Nuclear Information System (INIS)

Adamczyk, Wojciech P.; Kozołub, Paweł; Klimanek, Adam; Białecki, Ryszard A.; Andrzejczyk, Marek; Klajny, Marcin

2015-01-01

Measured and numerical results of air-fuel combustion process within large scale industrial circulating fluidized bed (CFB) boiler is presented in this paper. For numerical simulations the industrial compact CFB boiler was selected. Numerical simulations were carried out using three-dimensional model where the dense particulate transport phenomenon was simultaneously modelled with combustion process. The fluidization process was modelled using the hybrid Euler-Lagrange approach. The impact of the geometrical model simplification on predicted mass distribution and temperature profiles over CFB boiler combustion chamber two kinds of geometrical models were used, namely the complete model which consist of combustion chamber, solid separators, external solid super-heaters and simplified boiler geometry which was reduced to the combustion chamber. The evaluated temperature and pressure profiles during numerical simulations were compared against measured data collected during boiler air-fuel operation. Collected data was also used for validating numerical model of the oxy-fuel combustion model. Stability of the model and its sensitivity on changes of several input parameters were studied. The comparison of the pressure and temperature profiles for all considered cases gave comparable trends in contrary to measured data. Moreover, some additional test was carried out the check the influence of radiative heat transfer on predicted temperature profile within the CFB boiler. - Highlights: • Hybrid Euler-Lagrange approach was used for modelling particle transport, air- and oxy-fuel combustion process. • Numerical results were validated against measured data. • The influence of different boiler operating conditions on calculated temperature profile was investigated. • New strategy for resolving particle transport in circulating fluidized bed was shown

Jatropha oil and biogas in a dual fuel CI engine for rural electrification

International Nuclear Information System (INIS)

Luijten, C.C.M.; Kerkhof, E.

2011-01-01

This work presents the first dual fuel measurements with pure jatropha oil and biogas, using a 12 kW diesel engine generator. Reference tests are done with pure jatropha oil and with diesel to characterize the engine's thermal efficiency η t , volumetric efficiency η v and air-excess ratio λ versus output power. An extensive parameter study is done to predict/explain the effect of dual fuel operation on η v and λ. Dual fuel experiments, adding different qualities (CH 4 /CO 2 ratios) of synthetic biogas to the intake air, show that thermal efficiency is hardly affected for higher loads. For lower loads, biogas addition results in a decrease up to 10% in thermal efficiency, independent of biogas quality. Both η v and λ decrease with addition of biogas, in quantitative agreement with predictions. The engine runs well up to a certain heat release fraction of methane; at higher fractions irregularities are observed, probably attributable to light end-gas knock.

Methanol commercial aviation fuel

International Nuclear Information System (INIS)

Price, R.O.

1992-01-01

Southern California's heavy reliance on petroleum-fueled transportation has resulted in significant air pollution problems within the south Coast Air Basin (Basin) which stem directly from this near total dependence on fossil fuels. To deal with this pressing issue, recently enacted state legislation has proposed mandatory introduction of clean alternative fuels into ground transportation fleets operating within this area. The commercial air transportation sector, however, also exerts a significant impact on regional air quality which may exceed emission gains achieved in the ground transportation sector. This paper addresses the potential, through the implementation of methanol as a commercial aviation fuel, to improve regional air quality within the Basin and the need to flight test and demonstrate methanol as an environmentally preferable fuel in aircraft turbine engines

Thermal balance of a four stroke SI engine operating on hydrogen as a supplementary fuel

International Nuclear Information System (INIS)

Yueksel, F.; Ceviz, M.A.

2003-01-01

This paper investigates the effects of adding constant quantity hydrogen to gasoline-air mixture on SI engine thermal balance and performance. A four stroke, four-cylinder SI engine was used for conducting this study. Thermal balance tests were conducted for engine thermal efficiency, heat loss through the exhaust gases, heat loss to the cooling water and unaccounted losses (i.e. heat lost by lubricating oil, radiation), while performance tests were in respect to the brake power, specific fuel consumption and air ratio. Hydrogen supplementations were used with three different and fixed mass flow rates; 0.129, 0.168 and 0.208 kg h -1 at near three-fourth throttle opening position and variable engine speed ranging from 1000 to 4500 rpm. The results showed that supplementation of hydrogen to gasoline decreases the heat loss to cooling water and unaccounted losses, and the heat loss through the exhaust gas is nearly the same with pure gasoline experiments. Additionally, specific fuel consumption decreases, while the engine thermal efficiency and the air ratio increase. Engine performance parameters such as thermal efficiency and specific fuel consumption improved the level of the ratio of hydrogen mass flow rate to that of gasoline up to 5%

Alternate-Fueled Combustor-Sector Emissions

Science.gov (United States)

Saxena, Nikita T.; Thomas, Anna E.; Shouse, Dale T.; Neuroth, Craig; Hendricks, Robert C.; Lynch, Amy; Frayne, Charles W.; Stutrud, Jeffrey S.; Corporan, Edwin; Hankins, Terry

2013-01-01

In order to meet rapidly growing demand for fuel, as well as address environmental concerns, the aviation industry has been testing alternate fuels for performance and technical usability in commercial and military aircraft. In order to make alternate fuels (and blends) a viable option for aviation, the fuel must be able to perform at a similar or higher level than traditional petroleum fuel. They also attempt to curb harmful emissions, and therefore a truly effective alternate fuel would emit at or under the level of currently used fuel. This report analyzes data from gaseous and particulate emissions of an aircraft combustor sector. The data were evaluated at various inlet conditions, including variation in pressure and temperature, fuel-to-air ratios, and percent composition of alternate fuel. Traditional JP-8+100 data were taken as a baseline, and blends of JP-8+100 with synthetic-paraffinic-kerosene (SPK) fuel (Fischer-Tropsch (FT)) were used for comparison. Gaseous and particulate emissions, as well as flame luminosity, were assessed for differences between FT composition of 0, 50, and 100 percent. The data show that SPK fuel (an FT-derived fuel) had slightly lower harmful gaseous emissions, and smoke number information corroborated the hypothesis that SPK-FT fuels are cleaner burning fuels.

A novel structure of scalable air-cathode without Nafion and Pt by rolling activated carbon and PTFE as catalyst layer in microbial fuel cells.

Science.gov (United States)

Dong, Heng; Yu, Hongbing; Wang, Xin; Zhou, Qixing; Feng, Junli

2012-11-01

Single chambered air-cathode microbial fuel cells (MFCs) are promising to be scaled up as sustainable wastewater treatment systems. However, the current air-cathode made by brushing noble metal catalyst and Nafion binder onto carbon matrix becomes one of the biggest bottlenecks for the further development of MFCs due to its high cost, huge labor-consuming and less accuracy. A novel structure of air-cathode was constructed here by rolling activated carbon (AC) and polytetrafluoroethylene (PTFE) as catalyst layer to enhance the reproducibility and improve the performance by an optimized three-phase interface (TPI). Air-cathodes with AC/PTFE ratios of 3, 5, 6, 8 and 11 in the catalyst layer were prepared, and the physical and electrochemical techniques were employed to investigate their surface microstructure and electrochemical characteristics. Uniform cross-linked ropiness networks were observed from the catalyst layer of all the cathodes and increased as the AC/PTFE ratio decreased, while the exchange currents were positively related to this ratio. Maximum power densities (MPDs) decreased as follows: AC/PTFE = 6 (802 mW m(-2) at 3.4 A m(-2)), 5 (704 mW m(-2) at 2.2 mA m(-2)), 8 (647 mW m(-2) at 2.2 A m(-2)), 3 (597 mW m(-2) at 2.1 A m(-2)) and 11 (584 mW m(-2) at 2.0 mA m(-2)), which was due to the changes of both the capacitance characteristics and conductivities according to the electrochemical impedance spectrum (EIS) analysis. This study demonstrated that inexpensive, highly reproducible, high performance and scalable air-cathode can be produced by rolling method without using noble metal and expensive binder. Copyright © 2012 Elsevier Ltd. All rights reserved.

Performance evaluation of a stack cooling system using CO{sub 2} air conditioner in fuel cell vehicles

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Chul; Won, Jong Phil [Thermal Management Research Center, Korea Automotive Technology Institute, Chungnam 330-912 (Korea); Park, Yong Sun; Lim, Tae Won [Corporate Research and Development Division, Hyundai-Kia Motors, Gyeonggi 449-912 (Korea); Kim, Min Soo [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744 (Korea)

2009-01-15

A relation between the heat release from a fuel cell stack and an air conditioning system's performance was investigated. The air conditioning system installed in a fuel cell vehicle can be used for stack cooling when additional stack heat release is required over a fixed radiator capacity during high vehicle power generation. This study investigated the performance of a stack cooling system using CO{sub 2} air conditioner at various operating conditions. Also, the heat releasing effectiveness and mutual interference were analyzed and compared with those for the conventional radiator cooling system with/without cabin cooling. When the radiator coolant inlet temperature and flow rate were 65 C and 80 L/min, respectively, for the outdoor air inlet speed of 5 m/s, the heat release of the stack cooling system with the aid of CO{sub 2} air conditioner increased up to 36% more than that of the conventional radiator cooling system with cabin cooling. Furthermore, this increased by 7% versus the case without cabin cooling. (author)

Impact of Equivalence Ratio on the Macrostructure of Premixed Swirling CH 4 /Air and CH 4 /O 2 /CO 2 Flames

KAUST Repository

Watanabe, Hirotatsu

2015-06-15

Premixed CH4/O2/CO2 flames (oxy-flames) and CH4/air flames (air-flames) were experimentally studied in a swirl-stabilized combustor. For comparing oxy and air flames, the same equivalence ratio and adiabatic flame temperature were used. CO2 dilution was adjusted to attain the same adiabatic temperature for the oxy-flame and the corresponding air-flame while keeping the equivalence ratio and Reynolds number (=20,000) the same. For high equivalence ratios, we observed flames stabilized along the inner and outer shear layers of the swirling flow and sudden expansion, respectively, in both flames. However, one notable difference between the two flames appears as the equivalence ratio reaches 0.60. At this point, the outer shear layer flame disappears in the air-flame while it persists in the oxy-flame, despite the lower burning velocity of the oxy-flame. Prior PIV measurements (Ref. 9) showed that the strains along the outer shear layer are higher than along the inner shear layer. Therefore, the extinction strain rates in both flames were calculated using a counter-flow premixed twin flame configuration. Calculations at the equivalence ratio of 0.60 show that the extinction strain rate is higher in the oxy than in the air flame, which help explain why it persists on the outer shear layer with higher strain rate. It is likely that extinction strain rates contribute to the oxy-flame stabilization when air flame extinguish in the outer shear layer. However, the trend reverses at higher equivalence ratio, and the cross point of the extinction strain rate appears at equivalence ratio of 0.64.

Advanced Hydrocarbon Fuel Development

Science.gov (United States)

Bai, S. Don; Rodgers, Stephen L. (Technical Monitor)

2000-01-01

As a part of a high energy density materials (HEDM) development, the hot fire tests for Quadricyclane, 1,7 Octadiyne, AFRL-1, Biclopropylidene, and CINCH (Dimethyl amino ethyl azide) have been conducted at NASA/MSFC. The first 4 materials for this task are provided from Air Force Research Laboratory at Edward Air Force Base and US Army provided CINCH. The performance of these fuels is compared with RP-1. The preliminary results of these tests are presented. The preliminary results of Quadricyclane tests indicate that the specific impulse and c-star efficiency for quadricyclane at the mixture ratio 1.94 are approximately 5 sec and 105 ft/sec better than the RP-1 at mixture ratio 1.9. The 1,7 Octadiyne test indicate that the specific impulse and c-star efficiency at the mixture ratio 2.1 are approximately -1 sec and 89 ft/sec differ than the RP-1 at mixture ratio 2.04. The Quadricyclane soot buildup at the combustor is a little more than RP-1, but detail study of soot formation is not considered at this time. There was no visual soot buildup for the 1,7 Octadiyne and AFRL-1.

Compact modeling of a telecom back-up unit powered by air-cooled proton exchange membrane fuel cell

DEFF Research Database (Denmark)

Gao, Xin; Kær, Søren Knudsen

2018-01-01

Applications of proton exchange membrane fuel cells (PEMFC’s) are expanding in portable, automotive and stationary markets. One promising application is the back-up power for telecommunication applications in remote areas where usually air-cooled PMEFC’s are used. An air-cooled PEMFC system is much...

High-Performance Carbon Aerogel Air Cathodes for Microbial Fuel Cells

KAUST Repository

Zhang, Xiaoyuan

2016-08-11

Microbial fuel cells (MFCs) can generate electricity from the oxidation of organic substrates using anodic exoelectrogenic bacteria and have great potential for harvesting electric energy from wastewater. Improving oxygen reduction reaction (ORR) performance at a neutral pH is needed for efficient energy production. Here we show a nitrogen doped (≈4 wt%) ionothermal carbon aerogel (NDC) with a high surface area, large pore volume, and hierarchical porosity, with good electrocatalytic properties for ORR in MFCs. The MFCs using NDC air cathodes achieved a high maximum power density of 2300 mW m−2, which was 1.7 times higher than the most commonly used Pt/C air cathodes and also higher than most state-of-the-art ORR catalyst air cathodes. Rotating disk electrode measurements verified the superior electrocatalytic activity of NDC with an efficient four-electron transfer pathway (n=3.9). These findings highlight NDC as a better-performing and cost-efficient catalyst compared with Pt/C, making it highly viable for MFC applications.

Power generation by packed-bed air-cathode microbial fuel cells

KAUST Repository

Zhang, Xiaoyuan

2013-08-01

Catalysts and catalyst binders are significant portions of the cost of microbial fuel cell (MFC) cathodes. Many materials have been tested as aqueous cathodes, but air-cathodes are needed to avoid energy demands for water aeration. Packed-bed air-cathodes were constructed without expensive binders or diffusion layers using four inexpensive carbon-based materials. Cathodes made from activated carbon produced the largest maximum power density of 676±93mW/m2, followed by semi-coke (376±47mW/m2), graphite (122±14mW/m2) and carbon felt (60±43mW/m2). Increasing the mass of activated carbon and semi-coke from 5 to ≥15g significantly reduced power generation because of a reduction in oxygen transfer due to a thicker water layer in the cathode (~3 or ~6cm). These results indicate that a thin packed layer of activated carbon or semi-coke can be used to make inexpensive air-cathodes for MFCs. © 2013 Elsevier Ltd.

Clean/alternative fueled fleet programs - 1990 Amendments to the Clean Air Act, the Colorado Air Pollution Prevention and Control Act, and Denver City and County regulations

International Nuclear Information System (INIS)

Bowles, S.L.; Manderino, L.A.

1993-01-01

Despite substantial regulations for nearly two decades, attainment of this ambient standards for ozone and carbon monoxide (CO) remain difficult goals to achieve, Even with of ozone precursors and CO. The 1990 Amendments to the Clean Air Act (CAA90) prescribe further reductions of mobile source emissions. One such reduction strategy is using clean fuels, such as methanol, ethanol, or other alcohols (in blends of 85 percent or more alcohol with gasoline or other fuel), reformulated gasoline or diesel, natural gas, liquified petroleum gas, hydrogen, or electricity. There are regulatory measures involving special fuels which will be required in areas heavily polluted with ozone and CO. The state of Colorado recently passed the 1992 Air Pollution Prevention and Control Act which included provisions for the use of alternative fuels which will be implemented in 1994. In addition to adhering to the Colorado state regulations, the city and county of Denver also have regulations pertaining to the use of alternative fuels in fleets of 10 or more vehicles. Denver's program began in 1992. This paper will address the issue of fleet conversion and its impact on industry in Colorado, and Denver in particular

Fuel flexible distributed combustion for efficient and clean gas turbine engines

International Nuclear Information System (INIS)

Khalil, Ahmed E.E.; Gupta, Ashwani K.

2013-01-01

Highlights: • Examined distributed combustion for gas turbines applications using HiTAC. • Gaseous, liquid, conventional and bio-fuels are examined with ultra-low emissions. • Novel design of fuel flexibility without any atomizer for liquid fuel sprays. • Demonstrated fuel flexibility with emissions x and CO, low noise, enhanced stability, higher efficiency and alleviation of combustion instability. Distributed reaction conditions were achieved using swirl for desirable controlled mixing between the injected air, fuel and hot reactive gases from within the combustor prior to mixture ignition. In this paper, distributed combustion is further investigated using a variety of fuels. Gaseous (methane, diluted methane, hydrogen enriched methane and propane) and liquid fuels, including both traditional (kerosene) and alternate fuels (ethanol) that cover a wide range of calorific values are investigated with emphasis on pollutants emission and combustor performance with each fuel. For liquid fuels, no atomization or spray device was used. Performance evaluation with the different fuels was established to outline the flexibility of the combustor using a wide range of fuels of different composition, phase and calorific value with specific focus on ultra-low pollutants emission. Results obtained on pollutants emission and OH * chemiluminescence for the specific fuels at various equivalence ratios are presented. Near distributed combustion conditions with less than 8 PPM of NO emission were demonstrated under novel premixed conditions for the various fuels tested at heat (energy) release intensity (HRI) of 27 MW/m 3 -atm. and a rather high equivalence ratio of 0.6. Higher equivalence ratios lacked favorable distributed combustion conditions. For the same conditions, CO emission varied for each fuel; less than 10 ppm were demonstrated for methane based fuels, while heavier liquid fuels provided less than 40 ppm CO emissions. Lower emissions of NO ( x can be possible by

Kinetics of NO formation and decay in nanosecond pulse discharges in Air, H2-Air, and C2H4-Air mixtures

International Nuclear Information System (INIS)

Burnette, David; Shkurenkov, Ivan; Adamovich, Igor V; Lempert, Walter R

2016-01-01

Time-resolved, absolute NO and N atom number densities are measured by NO Laser Induced Fluorescence (LIF) and N Two-Photon Absorption LIF in a diffuse plasma filament, nanosecond pulse discharge in dry air, hydrogen-air, and ethylene-air mixtures at 40 Torr, over a wide range of equivalence ratios. The results are compared with kinetic modeling calculations incorporating pulsed discharge dynamics, kinetics of vibrationally and electronically excited states of nitrogen, plasma chemical reactions, and radial transport. The results show that in air afterglow, NO decay occurs primarily by the reaction with N atoms, NO  +  N  →  N 2   +  O. In the presence of hydrogen, this reaction is mitigated by reaction of N atoms with OH, N  +  OH  →  NO  +  H, resulting in significant reduction of N atom number density in the afterglow, additional NO production, and considerably higher NO number densities. In fuel-lean ethylene-air mixtures, a similar trend (i.e. N atom concentration reduction and NO number density increase) is observed, although [NO] increase on ms time scale is not as pronounced as in H 2 -air mixtures. In near-stoichiometric and fuel-lean ethylene-air mixtures, when N atom number density was below detection limit, NO concentration was measured to be lower than in air plasma. These results suggest that NO kinetics in hydrocarbon-air plasmas is more complex compared to air and hydrogen-air plasmas, additional NO reaction pathways may well be possible, and their analysis requires further kinetic modeling calculations. (paper)

Optimization of Fuel Cell System Operating Conditions for Fuel Cell Vehicles

OpenAIRE

Zhao, Hengbing; Burke, Andy

2008-01-01

Proton Exchange Membrane fuel cell (PEMFC) technology for use in fuel cell vehicles and other applications has been intensively developed in recent decades. Besides the fuel cell stack, air and fuel control and thermal and water management are major challenges in the development of the fuel cell for vehicle applications. The air supply system can have a major impact on overall system efficiency. In this paper a fuel cell system model for optimizing system operating conditions was developed wh...

The ratio of long-lived to short-lived radon-222 progeny concentrations in ground-level air

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, H.; Winkler, R. [Institut fuer Strahlenschutz, GSF-Forschungszentrum fuer Umwelt und Gesundheit, Neuherberg Oberschleissheim (Germany)

1996-02-09

The ratio of {sup 210}Pb air concentration to the short-lived radon ({sup 222}Rn) decay products concentration at ground level was investigated at a semi-rural location 10 km north of Munich, south Germany, for a period of 11 years (1982-1992). The average ratio from 132 monthly mean values has been found to be (7.5{+-}2.2) x 10{sup -5} (arithmetic mean{+-}S.D.). While the time series of the short-lived radon daughter concentration exhibit a distinct seasonal pattern with maxima mostly in October of each year, the course of {sup 210}Pb air concentration is characterized by high values from October through February. Consequently, high ratios of {sup 210}Pb to short-lived decay product concentration are often observed in the winter months of December-February. To study the influence of meteorological conditions on this behaviour, {sup 210}Pb and {sup 214}Pb concentrations were measured on a short-term basis with sampling intervals of 2-3 days from October 1991 to November 1992. The air concentrations obtained within those intervals were then correlated with actual meteorological parameters. On the base of this investigation the seasonal behaviour can essentially be explained by the more frequent inversion weather conditions in winter than in the summer months. At the same location, the average ratio of {sup 210}Po to {sup 210}Pb concentration in ground level air has been found to be 0.079 from 459 weakly mean values between 1976 and 1985. Hence, the corresponding average ratios of the short-lived radon daughters (EEC) to {sup 210}Pb and {sup 210}Po, were 1:7.5x10{sup -5} and 1:0.6 x 10{sup -5}, respectively.

Logistic Fuel Processor Development

National Research Council Canada - National Science Library

Salavani, Reza

2004-01-01

The Air Base Technologies Division of the Air Force Research Laboratory has developed a logistic fuel processor that removes the sulfur content of the fuel and in the process converts logistic fuel...

The emission analysis of an IDI diesel engine fueled with methyl ester of waste frying palm oil and its blends

Energy Technology Data Exchange (ETDEWEB)

Ozsezen, Ahmet Necati; Canakci, Mustafa [Department of Automotive Engineering Technology, Kocaeli University, 41380, Izmit (Turkey); Alternative Fuels R and D Center, Kocaeli University, 41275, Izmit (Turkey)

2010-12-15

In this study, the exhaust emissions of an unmodified diesel engine fueled with methyl ester of waste frying palm-oil (biodiesel) and its blends with petroleum based diesel fuel (PBDF) were investigated at the full load-variable speed condition. The relationships between the fuel properties and the air-fuel equivalence ratio, fuel line pressure, start of injection (SOI) timing, and ignition delay were also discussed to explain their effects on the emissions. The obtained test results were compared with the reference values which were determined by using PBDF. The results showed that when biodiesel was used in the test engine, the fuel line pressure increased while air-fuel equivalence ratio and ignition delay decreased. These behaviors affected the combustion phenomena of biodiesel which caused to reduction 57% in carbon monoxide (CO) emission, about 40% in unburned hydrocarbon (HC) emission and about 23% in smoke opacity when compared with PBDF. However, NO{sub x} and CO{sub 2} emissions of the biodiesel have showed different behaviors in terms of the engine speed. (author)

Atomization of JP-10/B4C gelled slurry fuel

OpenAIRE

Guglielmi, John David

1992-01-01

The atomization of a gelled boron slurry fuel using two commercially available airblast atomizers was studied at atmospheric pressure in non-reacting flow. The atomization of water was also characterized for comparison. Each atomizer was operated at two different liquid mass flow rates and several air/ fuel ratios. Drop size distribution was measured using a Malvern 2600 HSD Laser Diffraction Particle Sizer, Drop sizes acceptable for use in ramjet combustors could be obtained f...

Electronic modification of Pt via Ti and Se as tolerant cathodes in air-breathing methanol microfluidic fuel cells.

Science.gov (United States)

Ma, Jiwei; Habrioux, Aurélien; Morais, Cláudia; Alonso-Vante, Nicolas

2014-07-21

We reported herein on the use of tolerant cathode catalysts such as carbon supported Pt(x)Ti(y) and/or Pt(x)Se(y) nanomaterials in an air-breathing methanol microfluidic fuel cell. In order to show the improvement of mixed-reactant fuel cell (MRFC) performances obtained with the developed tolerant catalysts, a classical Pt/C nanomaterial was used for comparison. Using 5 M methanol concentration in a situation where the fuel crossover is 100% (MRFC-mixed reactant fuel cell application), the maximum power density of the fuel cell with a Pt/C cathodic catalyst decreased by 80% in comparison with what is observed in the laminar flow fuel cell (LFFC) configuration. With Pt(x)Ti(y)/C and Pt(x)Se(y)/C cathode nanomaterials, the performance loss was only 55% and 20%, respectively. The evaluation of the tolerant cathode catalysts in an air-breathing microfluidic fuel cell suggests the development of a novel nanometric system that will not be size restricted. These interesting results are the consequence of the high methanol tolerance of these advanced electrocatalysts via surface electronic modification of Pt. Herein we used X-ray photoelectron and in situ FTIR spectroscopies to investigate the origin of the high methanol tolerance on modified Pt catalysts.

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

Energy Technology Data Exchange (ETDEWEB)

Seshaiah, N. [Mechanical Engineering Department, M.I.T.S, Madanapalle, Angallu-517325, A.P. (India)

2010-07-01

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.

Combustor exhaust-emissions and blowout-limits with diesel number 2 and Jet A fuels utilizing air-atomizing and pressure-atomizing nozzles

Science.gov (United States)

Ingebo, R. D.; Norgren, C. T.

1975-01-01

The effect of fuel properties on exhaust emissions and blowout limits of a high-pressure combustor segment is evaluated using a splash-groove air-atomizing fuel injector and a pressure-atomizing simplex fuel nozzle to burn both diesel number 2 and Jet A fuels. Exhaust emissions and blowout data are obtained and compared on the basis of the aromatic content and volatility of the two fuels. Exhaust smoke number and emission indices for oxides of nitrogen, carbon monoxide, and unburned hydrocarbons are determined for comparison. As compared to the pressure-atomizing nozzle, the air-atomizing nozzle is found to reduce nitrogen oxides by 20%, smoke number by 30%, carbon monoxide by 70%, and unburned hydrocarbons by 50% when used with diesel number 2 fuel. The higher concentration of aromatics and lower volatility of diesel number 2 fuel as compared to Jet A fuel appears to have the most detrimental effect on exhaust emissions. Smoke number and unburned hydrocarbons are twice as high with diesel number 2 as with Jet A fuel.

Impact of partial fuel switch on household air pollutants in sub-Sahara Africa.

Science.gov (United States)

Tumwesige, Vianney; Okello, Gabriel; Semple, Sean; Smith, Jo

2017-12-01

Over 700 million people in Sub-Saharan Africa depend on solid biomass fuel and use simple cookstoves in poorly ventilated kitchens, which results in high indoor concentrations of household air pollutants. Switching from biomass to biogas as a cooking fuel can reduce airborne emissions of fine particulate matter (PM 2.5 ) and carbon monoxide (CO), but households often only partially convert to biogas, continuing to use solid biomass fuels for part of their daily cooking needs. There is little evidence of the benefits of partial switching to biogas. This study monitored real-time PM 2.5 and CO concentrations in 35 households in Cameroon and Uganda where biogas and firewood (or charcoal) were used. The 24 h mean PM 2.5 concentrations in households that used: (1) firewood and charcoal; (2) both firewood (mean 54% cooking time) and biogas (mean 46% cooking time); and (3) only biogas, were 449 μg m -3 , 173 μg m -3 and 18 μg m -3 respectively. The corresponding 24 h mean CO concentrations were 14.2 ppm, 2.7 ppm and 0.5 ppm. Concentrations of both PM 2.5 and CO were high and exceeded the World Health Organisation guidelines when firewood and charcoal were used. Partially switching to biogas reduced CO exposure to below the World Health Organisation guidelines, but PM 2.5 concentrations were only below the 24 h recommended limits when households fully converted to biogas fuel. These results indicate that partial switching from solid fuels to biogas is not sufficient and continues to produce concentrations of household air pollution that are likely to harm the health of those exposed. Programmes introducing biogas should aim to ensure that household energy needs can be fully achieved using biogas with no requirement to continue using solid fuels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nondestructive analysis of the RA fuel burnup, Calculation of the gamma activity ratio of fission products in the fuel - program QU0C1

International Nuclear Information System (INIS)

Bulovic, V.F.

1973-01-01

The γ radiation of RA reactor fuel element was measured under precisely defined measuring conditions. The spectrum was analysed by spectrometer with semiconductor Ge(Li) detector. The gamma counting rate in the fuel spectrum is defined as a function of fission product activity, gamma energy and yield, fuel thickness and additional absorbers, dimensions of the gamma collimator. Activity ratio of two fission products is defined as a function of counting rate peaks and part of the mentioned quantities. Four options for calculating the activities for fission products are discussed. Three of them are covered by the QU0C1 code written in FORTRAN for the CDC 3600 computer. The code is included in this report [sr

Fossil Fuel-Derived Polycyclic Aromatic Hydrocarbons in the Taiwan Strait, China, and Fluxes across the Air-Water Interface.

Science.gov (United States)

Ya, Miaolei; Xu, Li; Wu, Yuling; Li, Yongyu; Zhao, Songhe; Wang, Xinhong

2018-06-14

On the basis of the application of compound-specific radiocarbon analysis (CSRA) and air-water exchange models, the contributions of fossil fuel and biomass burning derived polycyclic aromatic hydrocarbons (PAHs) as well as their air-water transport were elucidated. The results showed that fossil fuel-derived PAHs (an average contribution of 89%) presented the net volatilization process at the air-water interface of the Taiwan Strait in summer. Net volatile fluxes of the dominant fluorene and phenanthrene (>58% of the total PAHs) were 27 ± 2.8 μg m -2 day -1 , significantly higher than the dry deposition fluxes (average 0.43 μg m -2 day -1 ). The Δ 14 C contents of selected PAHs (fluorene, phenanthrene plus anthracene, fluoranthene, and pyrene) determined by CSRA in the dissolved seawater ranged from -997 ± 4‰ to -873 ± 6‰, indicating that 89-100% (95 ± 4%) of PAHs were supplied by fossil fuels. The South China Sea warm current originating from the southwest China in summer (98%) and the Min-Zhe coastal current originating from the north China in winter (97%) input more fossil fuel PAHs than the Jiulong River estuary (90%) and Xiamen harbor water (93%). The more radioactive decayed 14 C of fluoranthene (a 4-ring PAH) than that of phenanthrene and anthracene (3-ring PAHs) represented a greater fossil fuel contribution to the former in dissolved seawater.

Pressurized air cathodes for enhanced stability and power generation by microbial fuel cells

Science.gov (United States)

He, Weihua; Yang, Wulin; Tian, Yushi; Zhu, Xiuping; Liu, Jia; Feng, Yujie; Logan, Bruce E.

2016-11-01

Large differences between the water and air pressure in microbial fuel cells (MFCs) can deform and damage cathodes. To avoid deformation, the cathode air pressure was controlled to balance pressure differences between the air and water. Raising the air pressures from 0 to 10 kPa at a set cathode potential of -0.3 V (versus Ag/AgCl) enhanced cathode performance by 17%, but pressures ≥25 kPa decreased current and resulted in air leakage into the solution. Matching the air pressure with the water pressure avoided cathode deformation and improved performance. The maximum power density increased by 15%, from 1070 ± 20 to 1230 ± 70 mW m-2, with balanced air and water pressures of 10-25 kPa. Oxygen partial pressures ≥12.5 kPa in the cathode compartment maintained the oxygen reduction rate to be within 92 ± 1% of that in ambient air. The use of pressurized air flow through the cathode compartments can enable closer spacing of the cathodes compared to passive gas transfer systems, which could make the reactor design more compact. The energy cost of pressurizing the cathodes was estimated to be smaller than the increase in power that resulted from the use of pressurized cathodes.

Pressurized air cathodes for enhanced stability and power generation by microbial fuel cells

KAUST Repository

He, Weihua

2016-09-30

Large differences between the water and air pressure in microbial fuel cells (MFCs) can deform and damage cathodes. To avoid deformation, the cathode air pressure was controlled to balance pressure differences between the air and water. Raising the air pressures from 0 to 10 kPa at a set cathode potential of −0.3 V (versus Ag/AgCl) enhanced cathode performance by 17%, but pressures ≥25 kPa decreased current and resulted in air leakage into the solution. Matching the air pressure with the water pressure avoided cathode deformation and improved performance. The maximum power density increased by 15%, from 1070 ± 20 to 1230 ± 70 mW m, with balanced air and water pressures of 10–25 kPa. Oxygen partial pressures ≥12.5 kPa in the cathode compartment maintained the oxygen reduction rate to be within 92 ± 1% of that in ambient air. The use of pressurized air flow through the cathode compartments can enable closer spacing of the cathodes compared to passive gas transfer systems, which could make the reactor design more compact. The energy cost of pressurizing the cathodes was estimated to be smaller than the increase in power that resulted from the use of pressurized cathodes.

Effect of fuel volatility on performance of tail-pipe burner

Science.gov (United States)

Barson, Zelmar; Sargent, Arthur F , Jr

1951-01-01

Fuels having Reid vapor pressures of 6.3 and 1.0 pounds per square inch were investigated in a tail-pipe burner on an axial-flow-type turbojet engine at a simulated flight Mach number of 0.6 and altitudes from 20,000 to 45,000 feet. With the burner configuration used in this investigation, having a mixing length of only 8 inches between the fuel manifold and the flame holder, the low-vapor-pressure fuel gave lower combustion efficiency at a given tail-pipe fuel-air ratio. Because the exhaust-nozzle area was fixed, the lower efficiency resulted in lower thrust and higher specific fuel consumption. The maximum altitude at which the burner would operate was practically unaffected by the change in fuel volatility.

Influence of air mass source sector on variations in CO2 mixing ratio at a boreal site in northern Finland

International Nuclear Information System (INIS)

Aalto, T.; Hatakka, J.; Viisanen, Y.

2003-01-01

CO 2 mixing ratio in air masses coming from different source sectors was studied at Pallas measurement station in Lapland. Source sectors were defined using back trajectories and wind direction measurements. Air masses from the North and West sectors showed an annual variation of 17 ppm, possibly affected by a long range transported marine air. A larger variation of 20 ppm was observed in air masses from the more continental South and East sectors. During late autumn mixing ratios in air masses from the South sector were high in comparison with the other sectors. Different methods for a source sector definition were considered for the site, located in a contoured terrain. 52%-73% of wind direction-based source sector definitions agreed with trajectory- based definitions. However, the number of cases with reliable sector definitions may remain low when considering all observations. Different definition methods can cause differences of the order of 1 ppm in sectorially selected monthly mean CO 2 mixing ratios. (orig.)

Engine combustion control at low loads via fuel reactivity stratification

Science.gov (United States)

Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

2014-10-07

A compression ignition (diesel) engine uses two or more fuel charges during a combustion cycle, with the fuel charges having two or more reactivities (e.g., different cetane numbers), in order to control the timing and duration of combustion. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot). At low load and no load (idling) conditions, the aforementioned results are attained by restricting airflow to the combustion chamber during the intake stroke (as by throttling the incoming air at or prior to the combustion chamber's intake port) so that the cylinder air pressure is below ambient pressure at the start of the compression stroke.

Engine combustion control at low loads via fuel reactivity stratification

Energy Technology Data Exchange (ETDEWEB)

Reitz, Rolf Deneys; Hanson, Reed M.; Splitter, Derek A.; Kokjohn, Sage

2017-12-26

A compression ignition (diesel) engine uses two or more fuel charges during a combustion cycle, with the fuel charges having two or more reactivities (e.g., different cetane numbers), in order to control the timing and duration of combustion. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot). At low load and no load (idling) conditions, the aforementioned results are attained by restricting airflow to the combustion chamber during the intake stroke (as by throttling the incoming air at or prior to the combustion chamber's intake port) so that the cylinder air pressure is below ambient pressure at the start of the compression stroke.

Removal ratio of gaseous toluene and xylene transported from air to root zone via the stem by indoor plants.

Science.gov (United States)

Kim, K J; Kim, H J; Khalekuzzaman, M; Yoo, E H; Jung, H H; Jang, H S

2016-04-01

This work was designed to investigate the removal efficiency as well as the ratios of toluene and xylene transported from air to root zone via the stem and by direct diffusion from the air into the medium. Indoor plants (Schefflera actinophylla and Ficus benghalensis) were placed in a sealed test chamber. Shoot or root zone were sealed with a Teflon bag, and gaseous toluene and xylene were exposed. Removal efficiency of toluene and total xylene (m, p, o) was 13.3 and 7.0 μg·m(-3)·m(-2) leaf area over a 24-h period in S. actinophylla, and was 13.0 and 7.3 μg·m(-3)·m(-2) leaf area in F. benghalensis. Gaseous toluene and xylene in a chamber were absorbed through leaf and transported via the stem, and finally reached to root zone, and also transported by direct diffusion from the air into the medium. Toluene and xylene transported via the stem was decreased with time after exposure. Xylene transported via the stem was higher than that by direct diffusion from the air into the medium over a 24-h period. The ratios of toluene transported via the stem versus direct diffusion from the air into the medium were 46.3 and 53.7% in S. actinophylla, and 46.9 and 53.1% in F. benghalensis, for an average of 47 and 53% for both species. The ratios of m,p-xylene transported over 3 to 9 h via the stem versus direct diffusion from the air into the medium was 58.5 and 41.5% in S. actinophylla, and 60.7 and 39.3% in F. benghalensis, for an average of 60 and 40% for both species, whereas the ratios of o-xylene transported via the stem versus direct diffusion from the air into the medium were 61 and 39%. Both S. actinophylla and F. benghalensis removed toluene and xylene from the air. The ratios of toluene and xylene transported from air to root zone via the stem were 47 and 60 %, respectively. This result suggests that root zone is a significant contributor to gaseous toluene and xylene removal, and transported via the stem plays an important role in this process.

A new air-fuel WSGGM for better utility boiler simulation, design and optimization

DEFF Research Database (Denmark)

Yin, Chungen

in computational fluid dynamics (CFD) simulation of air-fuel combustion processes. The WSGGM coefficients evaluated by Smith et al. (1982) for several partial pressures of CO2 and H2O vapor are often used for gas temperatures up to 2400K, which is supplemented by the coefficient values presented by Coppalle...

Fuel savings through air management optimization; Kraftstoffeinsparung durch Optimierung der Drucklufterzeugung und -aufbereitung

Energy Technology Data Exchange (ETDEWEB)

Wilken, Christoph; Son, Frank van [WABCO, Hannover (Germany)

2009-07-01

Fuel prices, vehicles' total cost of ownership, CO2 reductions by further environmental regulations become more and more a major driver for the development of energy efficient products, operating in a commercial vehicle. By example for the delivery and management of compressed air in a commercial vehicle, a compressor and an electronic controlled air processing unit (WABCO E-APU) are able to contribute a significant impact on energy savings, once through the way of creating compressed air and secondly by intelligent control of the compressor and the pressure levels, through an E-APU. Starting with the generation of compressed air, WABCO offers different systems with varying influence on the vehicle's fuel consumption. Today's conventional compressor systems in Europe are mostly equipped with WABCO PR (Power Reduction) System, reducing the energy consumption of the compressor in its idle phases. Further reduction of energy consumption during compressor idling is given by the usage of clutch principles, where the energy consumption during theses idle phases is greatly reduced. Next step to reduce also the energy consumption during compressor on-load phases, was the development of the WABCO two stage compressors which are using, compared to conventional one stage compressors, a more energy efficient way of compressing the needed air. Most effective intelligent air management systems include a compressor, associated with an electronic controlled air processing system (WABCO E-APU). By performing intelligent regeneration and keeping the compressor line plus cartridge pressurized during compressor idling, it is possible to utilize shortest overrun phases for pumping compressed air into the system and herewith generate additional energy savings. In near future, more and more hybrid vehicles with high voltage systems will enter the market, the WABCO electronic driven compressor (e-comp) stands for the best choice. It runs at different speeds, independent of

Health and Household Air Pollution from Solid Fuel Use: The Needfor Improved Exposure Assessment

Science.gov (United States)

Background: Nearly half the world’s population relies on solid fuel combustion to meet basic household energy needs (e.g., cooking and heating). Resulting air pollution exposures are estimated to cause 3% of the global burden of disease. Large variability and a lack of resource...

Influence of swirl ratio on fuel distribution and cyclic variation under flash boiling conditions in a spark ignition direct injection gasoline engine

International Nuclear Information System (INIS)

Yang, Jie; Xu, Min; Hung, David L.S.; Wu, Qiang; Dong, Xue

2017-01-01

Highlights: • Influence of swirl on fuel distribution studied using laser induced fluorescence. • Gradient is sufficient for fuel spatial distribution variation analysis. • Close relation between fuel distribution and flame initiation/development. • Quantitative analysis shows high swirl suppresses variation of fuel distribution. • High order modes capable of identifying the distribution fluctuation patterns. - Abstract: One effective way of suppressing the cycle-to-cycle variation in engine is to design a combustion system that is robust to the root causes of engine variation over the entire engine working process. Flash boiling has been demonstrated as an ideal technique to produce stable fuel spray. But the generation of stable intake flow and fuel mixture remains challenging. In this study, to evaluate the capability of enhanced swirl flow to produce repeatable fuel mixture formation, the fuel distribution inside a single cylinder optical engine under two swirl ratios were measured using laser induced fluorescence technique. The swirl ratio was regulated by a swirl control valve installed in one of the intake ports. A 266 nm wavelength laser sheet from a frequency-quadrupled laser was directed into the optical engine through the quartz liner 15 mm below the tip of the spark plug. The fluorescence signal from the polycyclic aromatic hydrocarbon in gasoline was collected by applying a 320–420 nm band pass filter mounted in front of an intensified charge coupled device camera. Test results show that the in-cylinder fuel distribution is strongly influenced by the swirl ratio. Specifically, under high swirl condition, the fuel is mainly concentrated on the left side of the combustion chamber. While under the low swirl flow, fuel is distributed more randomly over the observing plane. This agrees well with the measurements of the stable flame location. Additionally, the cycle-to-cycle variation of the fuel distribution were analyzed. Results show that well

Air sea ratio reduction initiative

Energy Technology Data Exchange (ETDEWEB)

Oberle, Jean

2010-09-15

Airfreight is the most expensive mode of transportation as well as the most impacting in terms of CO{sup 2} emissions. It is 7 times more expensive on average to ship by air than shipping by sea 1. Airfreight transportation mode emits 30 times more CO{sup 2} than sea freight mode 2. These elements provided a compelling platform to design a global logistics program to initiate a modal shift from air to sea freight without compromising service to customers.

Aerosols emitted in underground mine air by diesel engine fueled with biodiesel.

Science.gov (United States)

Bugarski, Aleksandar D; Cauda, Emanuele G; Janisko, Samuel J; Hummer, Jon A; Patts, Larry D

2010-02-01

Using biodiesel in place of petroleum diesel is considered by several underground metal and nonmetal mine operators to be a viable strategy for reducing the exposure of miners to diesel particulate matter. This study was conducted in an underground experimental mine to evaluate the effects of soy methyl ester biodiesel on the concentrations and size distributions of diesel aerosols and nitric oxides in mine air. The objective was to compare the effects of neat and blended biodiesel fuels with those of ultralow sulfur petroleum diesel. The evaluation was performed using a mechanically controlled, naturally aspirated diesel engine equipped with a muffler and a diesel oxidation catalyst. The effects of biodiesel fuels on size distributions and number and total aerosol mass concentrations were found to be strongly dependent on engine operating conditions. When fueled with biodiesel fuels, the engine contributed less to elemental carbon concentrations for all engine operating modes and exhaust configurations. The substantial increases in number concentrations and fraction of organic carbon (OC) in total carbon over the baseline were observed when the engine was fueled with biodiesel fuels and operated at light-load operating conditions. Size distributions for all test conditions were found to be single modal and strongly affected by engine operating conditions, fuel type, and exhaust configuration. The peak and total number concentrations as well as median diameter decreased with an increase in the fraction of biodiesel in the fuels, particularly for high-load operating conditions. The effects of the diesel oxidation catalyst, commonly deployed to counteract the potential increase in OC emissions due to use of biodiesel, were found to vary depending upon fuel formulation and engine operating conditions. The catalyst was relatively effective in reducing aerosol number and mass concentrations, particularly at light-load conditions, but also showed the potential for an

Indoor air pollution from solid biomass fuels combustion in rural agricultural area of Tibet, China.

Science.gov (United States)

Gao, X; Yu, Q; Gu, Q; Chen, Y; Ding, K; Zhu, J; Chen, L

2009-06-01

In this study, we are trying to investigate the indoor air pollution and to estimate the residents' pollution exposure reduction of energy altering in rural Tibet. Daily PM(2.5) monitoring was conducted in indoor microenvironments like kitchen, living-room, bedroom, and yard in rural Tibet from December 2006 to March 2007. For kitchen air pollution, impact of two fuel types, methane and solid biomass fuels (SBFs), were compared. Questionnaire survey on the domestic energy pattern and residents' daily activity pattern was performed in Zha-nang County. Daily average PM(2.5) concentrations in kitchen, living-room, bedroom, and yard were 134.91 microg/m(3) (mean, n = 45, 95%CI 84.02, 185.80), 103.61 microg/m(3) (mean, n = 21, 95%CI 85.77, 121.45), 76.13 microg/m(3) (mean, n = 18, 95%CI 57.22, 95.04), and 78.33 microg/m(3) (mean, n = 34, 95%CI 60.00, 96.65) respectively. Using SBFs in kitchen resulted in higher indoor pollution than using methane. PM(2.5) concentrations in kitchen with dung cake, fuel wood and methane use were 117.41 microg/m(3) (mean, n = 18, 95%CI 71.03, 163.79), 271.11 microg/m(3) (mean, n = 12, 95%CI 104.74, 437.48), and 46.96 microg/m(3) (mean, n = 15, 95%CI 28.10, 65.82) respectively. Family income has significant influence on cooking energy choice, while the lack of commercial energy supply affects the energy choice for heating more. The effects of two countermeasures to improve indoor air quality were estimated in this research. One is to replace SBFs by clean energy like methane, the other is to separate the cooking place from other rooms and by applying these countermeasures, residents' exposure to particulate matters would reduce by 25-50% (methane) or 20-30% (separation) compared to the present situation. Indoor air pollution caused by solid biomass fuels is one of the most important burdens of disease in the developing countries, which attracts the attention of environment and public health researchers, as well as policy makers. This paper

Electricity generation from fermented primary sludge using single-chamber air-cathode microbial fuel cells

KAUST Repository

Yang, Fei; Ren, Lijiao; Pu, Yuepu; Logan, Bruce E.

2013-01-01

Single-chamber air-cathode microbial fuel cells (MFCs) were used to generate electricity from fermented primary sludge. Fermentation (30°C, 9days) decreased total suspended solids (26.1-16.5g/L), volatile suspended solids (24.1-15.3g/L) and pH (5

Energetic and exergetic analyses of a variable compression ratio spark ignition gas engine

International Nuclear Information System (INIS)

Javaheri, A.; Esfahanian, V.; Salavati-Zadeh, A.; Darzi, M.

2014-01-01

Highlights: • Effects of CR and λ on CNG SI ICE 1st and 2nd law analyses are experimentally studied. • The performance of pure methane and a real CNG are observed and compared. • The ratio of actual to Otto cycle thermal efficiencies is 0.78 for all cases. • At least 25.5% of destructed availability is due to combustion irreversibility. • With decrease in methane content, CNG shows more combustion irreversibility. - Abstract: Considering the significance of obtaining higher efficiencies from internal combustion engines (ICE) along with the growing role of natural gas as a fuel, the present work is set to explore the effects of compression ratio (CR hereafter) and air/fuel equivalence ratio (AFER hereafter) on the energy and exergy potentials in a gas-fueled spark ignition internal combustion engine. Experiments are carried out using a single cylinder, port injection, water cooled, variable compression ratio (VCR hereafter), spark ignition engine at a constant engine speed of 2000 rpm. The study involves CRs of 12, 14 and 16 and 10 AFERs between 0.8 and 1.25. Pure methane is utilized for the analysis. In addition, a natural gas blend with the minimum methane content among Iranian gas sources is also tested in order to investigate the effect of real natural gas on findings. The energy analysis involves input fuel power, indicated power and losses due to high temperature of exhaust gases and their unburned content, blow-by and heat loss. The exergy analysis is carried out for availability input and piston, exhaust, and losses availabilities along with destructed entropy. The analysis indicates an increase in the ratio of thermo-mechanical exhaust availability to fuel availability by CR with a maximum near stoichiometry, whereas it is shown that chemical exhaust exergy is not dependent on CR and reduces with AFER. In addition, it is indicated that the ratio of actual cycle to Otto cycle thermal efficiencies is about constant (about 0.784) with changing CR

Combustion Characteristics for Turbulent Prevaporized Premixed Flame Using Commercial Light Diesel and Kerosene Fuels

Directory of Open Access Journals (Sweden)

Mohamed S. Shehata

2014-01-01

Full Text Available Experimental study has been carried out for investigating fuel type, fuel blends, equivalence ratio, Reynolds number, inlet mixture temperature, and holes diameter of perforated plate affecting combustion process for turbulent prevaporized premixed air flames for different operating conditions. CO2, CO, H2, N2, C3H8, C2H6, C2H4, flame temperature, and gas flow velocity are measured along flame axis for different operating conditions. Gas chromatographic (GC and CO/CO2 infrared gas analyzer are used for measuring different species. Temperature is measured using thermocouple technique. Gas flow velocity is measured using pitot tube technique. The effect of kerosene percentage on concentration, flame temperature, and gas flow velocity is not linearly dependent. Correlations for adiabatic flame temperature for diesel and kerosene-air flames are obtained as function of mixture strength, fuel type, and inlet mixture temperature. Effect of equivalence ratio on combustion process for light diesel-air flame is greater than for kerosene-air flame. Flame temperature increases with increased Reynolds number for different operating conditions. Effect of Reynolds number on combustion process for light diesel flame is greater than for kerosene flame and also for rich flame is greater than for lean flame. The present work contributes to design and development of lean prevaporized premixed (LPP gas turbine combustors.

Jatropha oil and biogas in a dual fuel CI engine for rural electrification

Energy Technology Data Exchange (ETDEWEB)

Luijten, C.C.M.; Kerkhof, E. [Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 6500 MB Eindhoven (Netherlands)

2011-02-15

This work presents the first dual fuel measurements with pure jatropha oil and biogas, using a 12 kW diesel engine generator. Reference tests are done with pure jatropha oil and with diesel to characterize the engine's thermal efficiency {eta}{sub t}, volumetric efficiency {eta}{sub v} and air-excess ratio {lambda} versus output power. An extensive parameter study is done to predict/explain the effect of dual fuel operation on {eta}{sub v} and {lambda}. Dual fuel experiments, adding different qualities (CH{sub 4}/CO{sub 2} ratios) of synthetic biogas to the intake air, show that thermal efficiency is hardly affected for higher loads. For lower loads, biogas addition results in a decrease up to 10% in thermal efficiency, independent of biogas quality. Both {eta}{sub v} and {lambda} decrease with addition of biogas, in quantitative agreement with predictions. The engine runs well up to a certain heat release fraction of methane; at higher fractions irregularities are observed, probably attributable to light end-gas knock. (author)

77 FR 72746 - Regulation of Fuels and Fuel Additives: Modifications to Renewable Fuel Standard and Diesel...

Science.gov (United States)

2012-12-06

... Fuels and Fuel Additives: Modifications to Renewable Fuel Standard and Diesel Sulfur Programs AGENCY... Fuel Standard (``RFS'') program under section 211(o) of the Clean Air Act. The direct final rule also... marine diesel fuel produced by transmix processors, and the fuel marker requirements for 500 ppm sulfur...

Alternate-Fueled Combustor-Sector Performance

Science.gov (United States)

Thomas, Anna E.; Saxena, Nikita T.; Shouse, Dale T.; Neuroth, Craig; Hendricks, Robert C.; Lynch, Amy; Frayne, Charles W.; Stutrud, Jeffrey S.; Corporan, Edwin; Hankins, Terry

2013-01-01

In order to realize alternative fueling for military and commercial use, the industry has set forth guidelines that must be met by each fuel. These aviation fueling requirements are outlined in MIL-DTL-83133F(2008) or ASTM D 7566 Annex (2011) standards, and are classified as "drop-in" fuel replacements. This report provides combustor performance data for synthetic-paraffinic-kerosene- (SPK-) type (Fischer-Tropsch (FT)) fuel and blends with JP-8+100, relative to JP-8+100 as baseline fueling. Data were taken at various nominal inlet conditions: 75 psia (0.52 MPa) at 500 degF (533 K), 125 psia (0.86 MPa) at 625 degF (603 K), 175 psia (1.21 MPa) at 725 degF (658 K), and 225 psia (1.55 MPa) at 790 degF (694 K). Combustor performance analysis assessments were made for the change in flame temperatures, combustor efficiency, wall temperatures, and exhaust plane temperatures at 3, 4, and 5 percent combustor pressure drop (DP) for fuel:air ratios (F/A) ranging from 0.010 to 0.025. Significant general trends show lower liner temperatures and higher flame and combustor outlet temperatures with increases in FT fueling relative to JP-8+100 fueling. The latter affects both turbine efficiency and blade and vane lives.

Numerical study of turbulent normal diffusion flame CH4-air stabilized by coaxial burner

Directory of Open Access Journals (Sweden)

Riahi Zouhair

2013-01-01

Full Text Available The practical combustion systems such as combustion furnaces, gas turbine, engines, etc. employ non-premixed combustion due to its better flame stability, safety, and wide operating range as compared to premixed combustion. The present numerical study characterizes the turbulent flame of methane-air in a coaxial burner in order to determine the effect of airflow on the distribution of temperature, on gas consumption and on the emission of NOx. The results in this study are obtained by simulation on FLUENT code. The results demonstrate the influence of different parameters on the flame structure, temperature distribution and gas emissions, such as turbulence, fuel jet velocity, air jet velocity, equivalence ratio and mixture fraction. The lift-off height for a fixed fuel jet velocity is observed to increase monotonically with air jet velocity. Temperature and NOx emission decrease of important values with the equivalence ratio, it is maximum about the unity.

UO2 Fuel pellet impurities, pellet surface roughness and n(18O)/n(16O) ratios, applied to nuclear forensic science

International Nuclear Information System (INIS)

Pajo, L.

2001-01-01

In the last decade, law enforcement has faced the problem of illicit trafficking of nuclear materials. Nuclear forensic science is a new branch of science that enables the identification of seized nuclear material. The identification is not based on a fixed scheme, but further identification parameters are decided based on previous identification results. The analysis is carried out by using traditional analysis methods and applying modern measurement technology. The parameters are generally not unambiguous and not self-explanatory. In order to have a full picture about the origin of seized samples, several identification parameters should be used together and the measured data should be compared to corresponding data from known sources. A nuclear material database containing data from several fabrication plants is installed for the purpose. In this thesis the use of UO 2 fabrication plant specific parameters, fuel impurities, fuel pellet surface roughness and oxygen isotopic ratio in UO 2 were investigated for identification purposes in nuclear forensic science. The potential use of these parameters as 'fingerprints' is discussed for identification purposes of seized nuclear materials. Impurities of the fuel material vary slightly according to the fabrication method employed and a plant environment. Here the impurities of the seized UO 2 were used in order to have some clues about the origin of the fuel material by comparing a measured data to nuclear database information. More certainty in the identification was gained by surface roughness of the UO 2 fuel pellets, measured by mechanical surface profilometry. Categories in surface roughness between a different fuel element type and a producer were observed. For the time oxygen isotopic ratios were determined by Thermal Ionisation Mass Speckometry (TIMS). Thus a TIMS measurement method, using U 16 O + and U 18 0 + ions, was developed and optimised to achieve precise oxygen isotope ratio measurements for the

Using cathode spacers to minimize reactor size in air cathode microbial fuel cells

KAUST Repository

Yang, Qiao

2012-04-01

Scaling up microbial fuel cells (MFCs) will require more compact reactor designs. Spacers can be used to minimize the reactor size without adversely affecting performance. A single 1.5mm expanded plastic spacer (S1.5) produced a maximum power density (973±26mWm -2) that was similar to that of an MFC with the cathode exposed directly to air (no spacer). However, a very thin spacer (1.3mm) reduced power by 33%. Completely covering the air cathode with a solid plate did not eliminate power generation, indicating oxygen leakage into the reactor. The S1.5 spacer slightly increased columbic efficiencies (from 20% to 24%) as a result of reduced oxygen transfer into the system. Based on operating conditions (1000ς, CE=20%), it was estimated that 0.9Lh -1 of air would be needed for 1m 2 of cathode area suggesting active air flow may be needed for larger scale MFCs. © 2012 Elsevier Ltd.

Combustion and Emission Characteristics of Variable Compression Ignition Engine Fueled with Jatropha curcas Ethyl Ester Blends at Different Compression Ratio

Directory of Open Access Journals (Sweden)

Rajneesh Kumar

2014-01-01

Full Text Available Engine performance and emission characteristics of unmodified biodiesel fueled diesel engines are highly influenced by their ignition and combustion behavior. In this study, emission and combustion characteristics were studied when the engine operated using the different blends (B10, B20, B30, and B40 and normal diesel fuel (B0 as well as when varying the compression ratio from 16.5 : 1 to 17.5 : 1 to 18.5 : 1. The change of compression ratio from 16.5 : 1 to 18.5 : 1 resulted in 27.1%, 27.29%, 26.38%, 28.48%, and 34.68% increase in cylinder pressure for the blends B0, B10, B20, B30, and B40, respectively, at 75% of rated load conditions. Higher peak heat release rate increased by 23.19%, 14.03%, 26.32%, 21.87%, and 25.53% for the blends B0, B10, B20, B30, and B40, respectively, at 75% of rated load conditions, when compression ratio was increased from16.5 : 1 to 18.5 : 1. The delay period decreased by 21.26%, CO emission reduced by 14.28%, and NOx emission increased by 22.84% for B40 blends at 75% of rated load conditions, when compression ratio was increased from 16.5 : 1 to 18.5 : 1. It is concluded that Jatropha oil ester can be used as fuel in diesel engine by blending it with diesel fuel.

Design and Performance of LPG Fuel Mixer for Dual Fuel Diesel Engine

Science.gov (United States)

Desrial; Saputro, W.; Garcia, P. P.

2018-05-01

Small horizontal diesel engines are commonly used for agricultural machinery, however, availability of diesel fuel become one of big problems especially in remote area. Conversely, in line with government policy for conversion of kerosene into LPG for cooking, then LPG become more popular and available even in remote area. Therefore, LPG is potential fuel to replace the shortage of diesel fuel for operating diesel engine in remote area. The purpose of this study was to design mixing device for using dual fuel i.e. LPG and diesel fuel and evaluate its performance accordingly. Simulation by using CFD was done in order to analyze mixture characteristics of LPG in air intake manifold. The performance test was done by varying the amount of LPG injected in intake air at 20%, 25%, 30%, 35%, until 40%, respectively. Result of CFD contour simulation showed the best combination when mixing 30% LPG into the intake air. Performance test of this research revealed that mixing LPG in air intake can reduce the diesel fuel consumption about 0.7 l/hour (without load) and 1.14 l/hour (with load). Diesel engine revolution increases almost 300 rpm faster than when using diesel fuel only. Based on economic analysis, using the fuel combination (diesel fuel – LPG) is not recommended in the area near SPBU where the price of diesel fuel is standard. However, using the fuel combination LPG-diesel fuel is highly recommended in the remote areas in Indonesia where price of diesel fuel is comparatively expensive which will provide cheaper total fuel cost for diesel engine operation.

Inflight fuel tank temperature survey data

Science.gov (United States)

Pasion, A. J.

1979-01-01

Statistical summaries of the fuel and air temperature data for twelve different routes and for different aircraft models (B747, B707, DC-10 and DC-8), are given. The minimum fuel, total air and static air temperature expected for a 0.3% probability were summarized in table form. Minimum fuel temperature extremes agreed with calculated predictions and the minimum fuel temperature did not necessarily equal the minimum total air temperature even for extreme weather, long range flights.

Optimization of combustion chamber geometry and operating conditions for compression ignition engine fueled with pre-blended gasoline-diesel fuel

International Nuclear Information System (INIS)

Lee, Seokhwon; Jeon, Joonho; Park, Sungwook

2016-01-01

Highlights: • Pre-blended gasoline-diesel fuel was used with direct injection system. • KIVA-CHEMKIN code modeled dual-fuel fuel spray and combustion processes with discrete multi-component model. • The characteristics of Combustion and emission on pre-blended fuel was investigated with various fuel reactivities. • Optimization of combustion chamber shape improved combustion performance of the gasoline-diesel blended fuel engine. - Abstract: In this study, experiments and numerical simulations were used to improve the fuel efficiency of compression ignition engine using a gasoline-diesel blended fuel and an optimization technology. The blended fuel is directly injected into the cylinder with various blending ratios. Combustion and emission characteristics were investigated to explore the effects of gasoline ratio on fuel blend. The present study showed that the advantages of gasoline-diesel blended fuel, high thermal efficiency and low emission, were maximized using the numerical optimization method. The ignition delay and maximum pressure rise rate increased with the proportion of gasoline. As the gasoline fraction increased, the combustion duration and the indicated mean effective pressure decreased. The homogeneity of the fuel-air mixture was improved due to longer ignition delay. Soot emission was significantly reduced up to 90% compared to that of conventional diesel. The nitrogen oxides emissions of the blended fuel increased slightly when the start of injection was retarded toward top dead center. For the numerical study, KIVA-CHEMKIN multi-dimensional CFD code was used to model the combustion and emission characteristics of gasoline-diesel blended fuel. The micro genetic algorithm coupled with the KIVA-CHEMKIN code were used to optimize the combustion chamber shape and operating conditions to improve the combustion performance of the blended fuel engine. The optimized chamber geometry enhanced the fuel efficiency, for a level of nitrogen oxides

Hydrogen as automotive fuel

International Nuclear Information System (INIS)

Dini, D.; Ciancia, A.; Pede, G.; Sglavo, V.; ENEA, Rome

1992-01-01

An assessment of the technical/economic feasibility of the use of hydrogen as an automotive fuel is made based on analyses of the following: the chemical- physical properties of hydrogen in relation to its use in internal combustion engines; the modifications necessary to adapt internal combustion engines to hydrogen use; hydrogen fuel injection systems - with water vapour injection, cryogenic injection, and the low or high pressure injection of hydrogen directly into the combustion chamber; the current commercialization status of hydrogen automotive fuels; energy efficiency ratings; environmental impacts; in-vehicle storage systems - involving the use of hydrides, high pressure systems and liquid hydrogen storage systems; performance in terms of pay-load ratio; autonomous operation; and operating costs. The paper concludes that, considering current costs for hydrogen fuel production, distribution and use, at present, the employment of hydrogen fuelled vehicles is feasible only in highly polluted urban environments where the innovative vehicle's air pollution abatement characteristics would justify its high operating costs as compared with those of conventional automotive alternatives

An experimental and numerical analysis of the influence of the inlet temperature, equivalence ratio and compression ratio on the HCCI auto-ignition process of Primary Reference Fuels in an engine

OpenAIRE

Machrafi, Hatim; Cavadias

2008-01-01

In order to understand better the auto-ignition process in an HCCI engine, the influence of some important parameters on the auto-ignition is investigated. The inlet temperature, the equivalence ratio and the compression ratio were varied and their influence on the pressure, the heat release and the ignition delays were measured, The inlet temperature was changed from 25 to 70 degrees C and the equivalence ratio from 0.18 to 0.41, while the compression ratio varied from 6 to 13.5. The fuels t...

Dynamic Thermal Model And Control Of A Pem Fuel Cell System

DEFF Research Database (Denmark)

Liso, Vincenzo; Nielsen, Mads Pagh

2013-01-01

the fuel cell system. A PID temperature control is implemented to study the effect of stack temperature on settling times of other variables such as stack voltage, air flow rate, oxygen excess ratio and net power of the stack. The model allows an assessment of the effect of operating parameters (stack...... power output, cooling water flow rate, air flow rate, and environmental temperature) and parameter interactions on the system thermal performance. The model represents a useful tool to determine the operating temperatures of the various components of the thermal system, and thus to fully assess......A lumped parameter dynamic model is developed for predicting the stack performance, temperatures of the exit reactant gases and coolant liquid outlet in a proton-exchange membrane fuel cell (PEMFC) system. The air compressor, humidifier and cooling heat exchanger models are integrated to study...

Potential for air quality improvement in the Tokyo metropolitan area from use of hydrogen fuel

International Nuclear Information System (INIS)

Kruger, Paul; Murdock, Mork

1998-01-01

A revised estimation has been made of the local air quality improvement that can be achieved in Tokyo as a byproduct of a word-wide hydrogen energy economy based on global reduction of CO2 emission from fossil fuels. The study for the WE-NET Project in Japan examined the potential for reduction in nitrogen oxide emission with hydrogen fuel in the Tokyo metropolitan area where sufficient data exist on trends in population, vehicle registrations, traffic activity, and exhaust emissions. A dynamic model was developed to extrapolate the trends in these data to estimate future NOx emission rates in comparison to regulatory scenarios based on policy and technical decisions of the Tokyo Metropolitan Government for improvement of air quality in the metropolitan area. The results of the model show significant potential for reduction of NOx emission by the year 2020 with a concomitant reduction in mean roadside NOx concentration. (author)

Pyrolysis of biomass in a semi-industrial scale reactor: Study of the fuel-nitrogen oxidation during combustion of volatiles

International Nuclear Information System (INIS)

Mura, E.; Debono, O.; Villot, A.; Paviet, F.

2013-01-01

In this work, an experimental study of the NOx-fuel formation, carried out on a semi-industrial scale reactor during combustion of volatiles of the pyrolysis, is performed. Two different biomasses with different nitrogen contents such as a mixture of organic sludge and wood were tested. Results show that the temperature of pyrolysis does not obviously affect the production of NOx-fuel because of the most active precursors (NH 3 and HCN) are already released at low temperatures (400 °C). In the case of sludge mixture, the combustion conditions play the discriminating role in the production of NOx-fuel: the higher the excess air ratio the larger the production of nitrogen oxides from N-fuel. -- Highlights: • An experimental study of the pyrolysis of biomass from waste has been carried out. • The study consists in the analysis of NOx-fuel production during combustion. • The temperature of pyrolysis does not affect the production of NOx. • Only a small part of the N-fuel released in the volatile fraction is oxidized. • In the case of sewage sludge the excess air ratio affects the NOx production

78 FR 32223 - Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards

Science.gov (United States)

2013-05-29

...-OAR-2011-0135; FRL-9818-5] RIN 2060-A0 Control of Air Pollution From Motor Vehicles: Tier 3 Motor... extension of the public comment period for the proposed rule ``Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards'' (the proposed rule is hereinafter referred to as...

Extinction of corrugated hydrogen/air flames

International Nuclear Information System (INIS)

Mizomoto, M.; Asaka, Y.; Ikai, S.; Law, C.K.

1982-01-01

Recent studies on flammability limits reveal the importance of flow nonuniformity, flame curvature, and molecular and thermal diffusivities in determining the extinguishability and the associated limits of premixed fuel/air flames. In particular, it is found that conditions which favor extinction of a lean flame may cause intensification of a rich flame. In the present study the authors have experimentally determined the extinction characteristics and limits of highly curved hydrogen/air flames as represented by the opening of bunsen flame tips. Results show that the tip opens at a constant fuel equivalence ratio of phi = 1.15, regardless of the velocity and uniformity of the upstream flow. This critical mixture concentration, while being rich, is still on the lean side of that corresponding to the maximum burning velocity (phi = 1.8), implying that for highly diffusive systems, the relevant reference concentration is that for maximum burning velocity instead of stoichiometry

Performance and exhaust emissions in a natural-gas fueled dual-fuel engine; Tennen gas dual fuel kikan no seino oyobi haiki tokusei

Energy Technology Data Exchange (ETDEWEB)

Shioji, M.; Ishiyama, T.; Shibata, H. [Kyoto Univ., Kyoto (Japan). Inst. of Atomic Energy; Ikegami, M. [Fukui Institute of Technology, Fukui (Japan). Faculty of Engineering

2000-07-25

In order to establish the optimum fueling in a natural gas fueled dual fuel engine, tests were made for some operational parameters and their combination on the engine performances and the exhaust emissions. The results show that the gas oil quantity should be increased and gas oil injection timing should be advanced to suppress unburned hydrocarbon emission at middle and low output range, while the quantity should be reduced and the timing should be retarded to avoid onset of knock at high loads. The unburned hydrocarbon emission and the thermal efficiency are improved at the same load avoiding too lean natural gas premixture by restriction of intake charge air. However the improvement is limited because the ignition and initial combustion of pilot diesel fuel is deteriorated when the cylinder pressure is excessively lowered by throttling. The increase in pilot gas oil amount is effective for low-load operation and the adequate combination of throttle control and equivalence ratio ensures low hydrocarbon emission and the thermal efficiency comparable to diesel operation. (author)

Quantification of the effect of in-situ generated uranium metal on the experimentally determined O/U ratio of a sintered uranium dioxide fuel pellet

International Nuclear Information System (INIS)

Narasimha Murty, B.; Bharati Misra, U.; Yadav, R.B.; Srivastava, R.K.

2005-01-01

This paper describes quantitatively the effect of in-situ generated uranium metal (that could be formed due to the conducive manufacturing conditions) in a sintered uranium dioxide fuel pellet on the experimentally determined O/U ratio using analytical methods involving dissolution of the pellet material. To quantify the effect of in-situ generated uranium metal in the fuel pellet, a mathematical expression is derived for the actual O/U ratio in terms of the O/U ratio as determined by an experiment involving dissolution of the material and the quantity of uranium metal present in the uranium dioxide pellet. The utility of this derived mathematical expression is demonstrated by tabulating the calculated actual O/U ratios for varying amounts of uranium metal (from 5 to 95% in 5% intervals) and different O/U ratio values (from 2.001 to 2.015 in 0.001 intervals). This paper brings out the necessity of care to be exercised while interpreting the experimentally determined O/U ratio and emphasizes the fact that it is always safer to produce the nuclear fuel with oxygen to uranium ratios well below the specified maximum limit of 2.015. (author)

Performance Analysis of Air Breathing Proton Exchange Membrane Fuel Cell Stack (PEMFCS) At Different Operating Condition

Science.gov (United States)

Sunil, V.; Venkata siva, G.; Yoganjaneyulu, G.; Ravikumar, V. V.

2017-08-01

The answer for an emission free power source in future is in the form of fuel cells which combine hydrogen and oxygen producing electricity and a harmless by product-water. A proton exchange membrane (PEM) fuel cell is ideal for automotive applications. A single cell cannot supply the essential power for any application. Hence PEM fuel cell stacks are used. The effect of different operating parameters namely: type of convection, type of draught, hydrogen flow rate, hydrogen inlet pressure, ambient temperature and humidity, hydrogen humidity, cell orientation on the performance of air breathing PEM fuel cell stack was analyzed using a computerized fuel cell test station. Then, the fuel cell stack was subjected to different load conditions. It was found that the stack performs very poorly at full capacity (runs only for 30 min. but runs for 3 hours at 50% capacity). Hence, a detailed study was undertaken to maximize the duration of the stack’s performance at peak load.

Study of ammonia removal from coal-gasified fuel

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, Takeharu; Sato, Mikio [Central Research Inst. of Electric Power Industry, Yokosuka, Kanagawa (Japan)

1998-07-01

In integrated coal gasification combined-cycle power-generation (IGCC) systems, ammonia in gasified fuel is passed through a hot/dry type gas clean-up facility into a gas turbine. The ammonia is converted to nitrogen oxides in the gas turbine combustion process. Therefore, ammonia removal from coal-gasified fuel effectively reduces NO{sub x} emissions in IGCC systems. The authors clarified the optimum NO/NH{sub 3} ratio, the optimum concentration of added O{sub 2}, and the influence of CO, H{sub 2}, and CH{sub 4} in the coal-gasified fuel on NH{sub 3} decomposition and NO reduction through experiments using a tubular flow reactor and numerical analysis based on reaction kinetics. The main results were as follows: (1) The optimum NO/NH{sub 3} ratio for maximizing NH{sub 3} decomposition and NO reduction was about 1. (2) The NH{sub 3} decomposition ratio depended only on H{sub 2}, and decreased rapidly with increasing H{sub 2} concentration. (3) The NO reduction ratio decreased with an increasing H{sub 2} concentration. (4) The remaining CH{sub 4}, which was not decomposed by pyrolysis, increased with an increasing CH{sub 4} concentration and caused the reaction temperature to rise, as opposed to cases of CO and H{sub 2}. (5) The method was effective in decreasing total fixed nitrogen (TFN) by up to 40% and minimizing the total concentration of remaining NH{sub 3} and NO in air-blown, coal-gasified fuel.

Indoor air pollution and the health of children in biomass- and fossil-fuel users of Bangladesh: situation in two different seasons.

Science.gov (United States)

Khalequzzaman, Md; Kamijima, Michihiro; Sakai, Kiyoshi; Hoque, Bilqis Amin; Nakajima, Tamie

2010-07-01

Indoor air pollution levels are reported to be higher with biomass fuel, and a number of respiratory diseases in children are associated with pollution from burning such fuel. However, little is known about the situation in developing countries. The aim of the study was to compare indoor air pollution levels and prevalence of symptoms in children between biomass- and fossil-fuel-using households in different seasons in Bangladesh. We conducted a cross-sectional study among biomass- (n = 42) and fossil-fuel (n = 66) users having children Moulvibazar and Dhaka, Bangladesh. Health-related information of one child from each family was retrieved once in winter (January 2008) and once in summer (June 2008). The measured pollutants were carbon monoxide (CO), carbon dioxide (CO(2)), dust particles, volatile organic compounds (VOCs), and nitrogen dioxide. Mean concentration of dust particles and geometric mean concentrations of VOCs such as benzene, toluene, and xylene, which were significantly higher in biomass- than fossil-fuel-users' kitchens (p < 0.05), were significantly higher in winter than in summer (p < 0.05). Levels of CO and CO(2), which were significantly higher in biomass than fossil-fuel users (p < 0.05), were significantly higher in summer than winter (p < 0.05). However, no significant difference was found in the occurrence of symptoms between biomass- and fossil-fuel users either in winter or in summer. It was suggested that the measured indoor air pollution did not directly result in symptoms among children. Other factors may be involved.

The indicative effects of inefficient urban traffic flow on fuel cost and exhaust air pollutant emissions

CSIR Research Space (South Africa)

Moselakgomo, M

2015-07-01

Full Text Available Poor urban traffic management such as poor intersection controls, congestions, illegal roadway blockages and construction works causes “stop-go” driving conditions with excessive idling resulting in wasted fuel and increased air pollutant emissions...

Alternate-Fueled Combustion-Sector Emissions

Science.gov (United States)

Saxena, Nikita T.; Thomas, Anna E.; Shouse, Dale T.; Neuroth, Craig; Hendricks, Robert C.; Lynch, Amy; Frayne, Charles W.; Stutrud, Jeffrey S.; Corporan, Edwin; Hankins, Terry

2012-01-01

In order to meet rapidly growing demand for fuel, as well as address environmental concerns, the aviation industry has been testing alternate fuels for performance and technical usability in commercial and military aircraft. Currently, alternate aviation fuels must satisfy MIL-DTL- 83133F(2008) (military) or ASTM D 7566- Annex(2011) (commercial) standards and are termed drop-in fuel replacements. Fuel blends of up to 50% alternative fuel blended with petroleum (JP-8), which have become a practical alternative, are individually certified on the market. In order to make alternate fuels (and blends) a viable option for aviation, the fuel must be able to perform at a similar or higher level than traditional petroleum fuel. They also attempt to curb harmful emissions, and therefore a truly effective alternate fuel would emit at or under the level of currently used fuel. This paper analyzes data from gaseous and particulate emissions of an aircraft combustor sector. The data were evaluated at various inlet conditions, including variation in pressure and temperature, fuel-to-air ratios, and percent composition of alternate fuel. Traditional JP-8+100 data were taken as a baseline, and blends of JP- 8+100 with synthetic-paraffinic-kerosene (SPK) fuel (Fischer-Tropsch (FT)) were used for comparison. Gaseous and particulate emissions, as well as flame luminosity, were assessed for differences between FT composition of 0%, 50%, and 100%. The data showed that SPK fuel (a FT-derived fuel) had slightly lower harmful gaseous emissions, and smoke number information corroborated the hypothesis that SPK-FT fuels are cleaner burning fuels.

Control and experimental characterization of a methanol reformer for a 350 W high temperature polymer electrolyte membrane fuel cell system

DEFF Research Database (Denmark)

Andreasen, Søren Juhl; Kær, Søren Knudsen; Sahlin, Simon Lennart

2013-01-01

is the water and methanol mixture fuel flow and the burner fuel/air ratio and combined flow. An experimental setup is presented capable of testing the methanol reformer used in the Serenergy H3 350 Mobile Battery Charger; a high temperature polymer electrolyte membrane (HTPEM) fuel cell system......This work presents a control strategy for controlling the methanol reformer temperature of a 350 W high temperature polymer electrolyte membrane fuel cell system, by using a cascade control structure for reliable system operation. The primary states affecting the methanol catalyst bed temperature....... The experimental system consists of a fuel evaporator utilizing the high temperature waste gas from the cathode air cooled 45 cell HTPEM fuel cell stack. The fuel cells used are BASF P1000 MEAs which use phosphoric acid doped polybenzimidazole membranes. The resulting reformate gas output of the reformer system...

New fuel air control strategy for reducing NOx emissions from corner-fired utility boilers at medium-low loads

DEFF Research Database (Denmark)

Zhao, Sinan; Fang, Qingyan; Yin, Chungen

2017-01-01

Due to the rapidly growing renewable power, the fossil fuel power plants have to be increasingly operated under large and rapid load change conditions, which can induce various challenges. This work aims to reduce NOx emissions of large-scale corner-fired boilers operated at medium–low loads....... The combustion characteristics and NOx emissions from a 1000 MWe corner-fired tower boiler under different loads are investigated experimentally and numerically. A new control strategy for the annular fuel air is proposed and implemented in the boiler, in which the secondary air admitted to the furnace through...... the air annulus around each coal nozzle tip is controlled by the boiler load, instead of being controlled by the output of the connected mill as commonly used in this kind of power plant. Both the experimental and simulation results show that the new control strategy reduces NOx emissions at the entrance...

Experimental determination of spectral ratios and of neutrons energy spectrum in the fuel of the IPEN/MB-01 nuclear reactor

International Nuclear Information System (INIS)

Nunes, Beatriz Guimaraes

2012-01-01

This study aims to determine the spectral ratios and the neutron energy spectrum inside the fuel of IPEN/MB-01 Nuclear Reactor. These parameters are of great importance to accurately determine spectral physical parameters of nuclear reactors like reaction rates, fuel lifetime and also security parameters such as reactivity. For the experiment, activation detectors in the form of thin metal foils were introduced in a collapsible fuel rod. Then the rod was placed in the central position of the core which has a standard rectangular configuration of 26 x 28 fuel rods. There were used activation detectors from different elements such Au-197, U-238, Sc-45, Ni-58, Mg-24, Ti-47 and In-115 to cover a large range of the neutron energy spectrum. After the irradiation, the activation detectors were submitted to gamma spectrometry using a counting system with high purity Germanium, to obtain the reaction rates (saturation activity) per target nucleus. The spectral ratios were compared with calculated values obtained by the Monte Carlo method using the MCNP-4C code. The neutron energy spectrum was obtained inside the fuel rod using the SANDBP code with an input spectrum obtained by the MCNP-4C code, based on the saturation activity per target nucleus values of the activation detectors irradiated. (author)

Thermal management optimization of an air-cooled hydrogen fuel cell system in an extreme environmental condition

DEFF Research Database (Denmark)

Gao, Xin; Olesen, Anders Christian; Kær, Søren Knudsen

2018-01-01

An air-cooled proton exchange membrane (PEM) fuel cell system is designed and under manufacture for telecommunication back-up power. To enhance its competence in various environments, the system thermal feature is optimized in this work via simulation based on a computational fluid dynamics (CFD......, the intake airflow magnitude, is also studied for a more uniform airflow and in turn a suppressed temperature disparity inside the system. Following the guidelines drawn by this work on the system design and the operation setting, the air-cooled fuel cell system can be expected with better performances......) model. The model is three-dimensional (3D) and built in the commercial CFD package Fluent (ANSYS Inc.). It makes the full-scale system-level study feasible by only considering the system essences with adequate accuracy. Through the model, the optimization is attained in several aspects. Firstly...

Design, fabrication and testing of an air-breathing micro direct methanol fuel cell with compound anode flow field

International Nuclear Information System (INIS)

Wang, Luwen; Zhang, Yufeng; Zhao, Youran; An, Zijiang; Zhou, Zhiping; Liu, Xiaowei

2011-01-01

An air-breathing micro direct methanol fuel cell (μDMFC) with a compound anode flow field structure (composed of the parallel flow field and the perforated flow field) is designed, fabricated and tested. To better analyze the effect of the compound anode flow field on the mass transfer of methanol, the compound flow field with different open ratios (ratio of exposure area to total area) and thicknesses of current collectors is modeled and simulated. Micro process technologies are employed to fabricate the end plates and current collectors. The performances of the μDMFC with a compound anode flow field are measured under various operating parameters. Both the modeled and the experimental results show that, comparing the conventional parallel flow field, the compound one can enhance the mass transfer resistance of methanol from the flow field to the anode diffusion layer. The results also indicate that the μDMFC with an anode open ratio of 40% and a thickness of 300 µm has the optimal performance under the 7 M methanol which is three to four times higher than conventional flow fields. Finally, a 2 h stability test of the μDMFC is performed with a methanol concentration of 7 M and a flow velocity of 0.1 ml min −1 . The results indicate that the μDMFC can work steadily with high methanol concentration.

Characterization of laser-induced ignition of biogas-air mixtures

International Nuclear Information System (INIS)

Forsich, Christian; Lackner, Maximilian; Winter, Franz; Kopecek, Herbert; Wintner, Ernst

2004-01-01

Fuel-rich to fuel-lean biogas-air mixtures were ignited by a Nd:YAG laser at initial pressures of up to 3 MPa and compared to the ignition of methane-air mixtures. The investigations were performed in a constant volume vessel heatable up to 473 K. An InGaAsSb/AlGaAsSb quantum well ridge diode laser operating at 2.55 μm was used to track the generation of water in the vicinity of the laser spark in a semi-quantitative manner. Additionally, the flame emissions during the ignition process were recorded and a gas inhomogeneity index was deduced. Laser-induced ignition and its accompanying effects could be characterized on a time scale spanning four orders of magnitude. The presence of CO 2 in the biogas reduces the burning velocity. The flame emissions result in a much higher intensity for methane than it was the case during biogas ignition. This knowledge concludes that engines fuelled with biogas ultimately affect the performance of the process in a different way than with methane. Methane-air mixtures can be utilized in internal combustion engines with a higher air-fuel ratio than biogas. Comparing failed laser-induced ignition of methane-air and biogas-air mixtures similar results were obtained. The three parameters water absorbance, flame emission and the gas inhomogeneity index constitute a suitable tool for judging the quality of laser-induced ignition of hydrocarbon-air mixtures at elevated pressures and temperatures as encountered in internal combustion engines

Characterization of diesel fuel by chemical separation combined with capillary gas chromatography (GC) isotope ratio mass spectrometry (IRMS).

Science.gov (United States)

Harvey, Scott D; Jarman, Kristin H; Moran, James J; Sorensen, Christina M; Wright, Bob W

2012-09-15

The purpose of this study was to perform a preliminary investigation of compound-specific isotope analysis (CSIA) of diesel fuels to evaluate whether the technique could distinguish diesel samples from different sources/locations. The ability to differentiate or correlate diesel samples could be valuable for discovering fuel tax evasion schemes or for environmental forensic studies. Two urea adduction-based techniques were used to isolate the n-alkanes from the fuel. Both carbon isotope ratio (δ(13)C) and hydrogen isotope ratio (δD) values for the n-alkanes were then determined by CSIA in each sample. The samples investigated had δ(13)C values that ranged from -30.1‰ to -26.8‰, whereas δD values ranged from -83‰ to -156‰. Plots of δD versus δ(13)C with sample n-alkane points connected in order of increasing carbon number gave well-separated clusters with characteristic shapes for each sample. Principal components analysis (PCA) with δ(13)C, δD, or combined δ(13)C and δD data was applied to extract the maximum information content. PCA scores plots could clearly differentiate the samples, thereby demonstrating the potential of this approach for distinguishing (e.g., fingerprinting) fuel samples using δ(13)C and δD values. Copyright © 2012 Elsevier B.V. All rights reserved.

On the Experimental and Theoretical Investigations of Lean Partially Premixed Combustion, Burning Speed, Flame Instability and Plasma Formation of Alternative Fuels at High Temperatures and Pressures

Science.gov (United States)

Askari, Omid

This dissertation investigates the combustion and injection fundamental characteristics of different alternative fuels both experimentally and theoretically. The subjects such as lean partially premixed combustion of methane/hydrogen/air/diluent, methane high pressure direct-injection, thermal plasma formation, thermodynamic properties of hydrocarbon/air mixtures at high temperatures, laminar flames and flame morphology of synthetic gas (syngas) and Gas-to-Liquid (GTL) fuels were extensively studied in this work. These subjects will be summarized in three following paragraphs. The fundamentals of spray and partially premixed combustion characteristics of directly injected methane in a constant volume combustion chamber have been experimentally studied. The injected fuel jet generates turbulence in the vessel and forms a turbulent heterogeneous fuel-air mixture in the vessel, similar to that in a Compressed Natural Gas (CNG) Direct-Injection (DI) engines. The effect of different characteristics parameters such as spark delay time, stratification ratio, turbulence intensity, fuel injection pressure, chamber pressure, chamber temperature, Exhaust Gas recirculation (EGR) addition, hydrogen addition and equivalence ratio on flame propagation and emission concentrations were analyzed. As a part of this work and for the purpose of control and calibration of high pressure injector, spray development and characteristics including spray tip penetration, spray cone angle and overall equivalence ratio were evaluated under a wide range of fuel injection pressures of 30 to 90 atm and different chamber pressures of 1 to 5 atm. Thermodynamic properties of hydrocarbon/air plasma mixtures at ultra-high temperatures must be precisely calculated due to important influence on the flame kernel formation and propagation in combusting flows and spark discharge applications. A new algorithm based on the statistical thermodynamics was developed to calculate the ultra-high temperature plasma

Improved ASTM G72 Test Method for Ensuring Adequate Fuel-to-Oxidizer Ratios

Science.gov (United States)

Juarez, Alfredo; Harper, Susana Tapia

2016-01-01

The ASTM G72/G72M-15 Standard Test Method for Autogenous Ignition Temperature of Liquids and Solids in a High-Pressure Oxygen-Enriched Environment is currently used to evaluate materials for the ignition susceptibility driven by exposure to external heat in an enriched oxygen environment. Testing performed on highly volatile liquids such as cleaning solvents has proven problematic due to inconsistent test results (non-ignitions). Non-ignition results can be misinterpreted as favorable oxygen compatibility, although they are more likely associated with inadequate fuel-to-oxidizer ratios. Forced evaporation during purging and inadequate sample size were identified as two potential causes for inadequate available sample material during testing. In an effort to maintain adequate fuel-to-oxidizer ratios within the reaction vessel during test, several parameters were considered, including sample size, pretest sample chilling, pretest purging, and test pressure. Tests on a variety of solvents exhibiting a range of volatilities are presented in this paper. A proposed improvement to the standard test protocol as a result of this evaluation is also presented. Execution of the final proposed improved test protocol outlines an incremental step method of determining optimal conditions using increased sample sizes while considering test system safety limits. The proposed improved test method increases confidence in results obtained by utilizing the ASTM G72 autogenous ignition temperature test method and can aid in the oxygen compatibility assessment of highly volatile liquids and other conditions that may lead to false non-ignition results.

Carbonate-mediated Fe(II) oxidation in the air-cathode fuel cell: a kinetic model in terms of Fe(II) speciation.

Science.gov (United States)

Song, Wei; Zhai, Lin-Feng; Cui, Yu-Zhi; Sun, Min; Jiang, Yuan

2013-06-06

Due to the high redox activity of Fe(II) and its abundance in natural waters, the electro-oxidation of Fe(II) can be found in many air-cathode fuel cell systems, such as acid mine drainage fuel cells and sediment microbial fuel cells. To deeply understand these iron-related systems, it is essential to elucidate the kinetics and mechanisms involved in the electro-oxidation of Fe(II). This work aims to develop a kinetic model that adequately describes the electro-oxidation process of Fe(II) in air-cathode fuel cells. The speciation of Fe(II) is incorporated into the model, and contributions of individual Fe(II) species to the overall Fe(II) oxidation rate are quantitatively evaluated. The results show that the kinetic model can accurately predict the electro-oxidation rate of Fe(II) in air-cathode fuel cells. FeCO3, Fe(OH)2, and Fe(CO3)2(2-) are the most important species determining the electro-oxidation kinetics of Fe(II). The Fe(II) oxidation rate is primarily controlled by the oxidation of FeCO3 species at low pH, whereas at high pH Fe(OH)2 and Fe(CO3)2(2-) are the dominant species. Solution pH, carbonate concentration, and solution salinity are able to influence the electro-oxidation kinetics of Fe(II) through changing both distribution and kinetic activity of Fe(II) species.

A study of air breathing rockets. 3: Supersonic mode combustors

Science.gov (United States)

Masuya, G.; Chinzel, N.; Kudo, K.; Murakami, A.; Komuro, T.; Ishii, S.

An experimental study was made on supersonic mode combustors of an air breathing rocket engine. Supersonic streams of room-temperature air and hot fuel-rich rocket exhaust were coaxially mixed and burned in a concially diverging duct of 2 deg half-angle. The effect of air inlet Mach number and excess air ratio was investigated. Axial wall pressure distribution was measured to calculate one dimensional change of Mach number and stagnation temperature. Calculated results showed that supersonic combustion occurred in the duct. At the exit of the duct, gas sampling and Pitot pressure measurement was made, from which radial distributions of various properties were deduced. The distribution of mass fraction of elements from rocket exhaust showed poor mixing performance in the supersonic mode combustors compared with the previously investigated cylindrical subsonic mode combustors. Secondary combustion efficiency correlated well with the centerline mixing parameter, but not with Annushkin's non-dimensional combustor length. No major effect of air inlet Mach number or excess air ratio was seen within the range of conditions under which the experiment was conducted.

Anti-air pollution & energy conservation system for automobiles using leaded or unleaded gasoline, diesel or alternate fuel

Science.gov (United States)

Bose, Ranendra K.

2002-06-04

Exhaust gases from an internal combustion engine operating with leaded or unleaded gasoline or diesel or natural gas, are used for energizing a high-speed gas turbine. The convoluting gas discharge causes a first separation stage by stratifying of heavier and lighter exhaust gas components that exit from the turbine in opposite directions, the heavier components having a second stratifying separation in a vortex tube to separate combustible pollutants from non-combustible components. The non-combustible components exit a vortex tube open end to atmosphere. The lighter combustible, pollutants effected in the first separation are bubbled through a sodium hydroxide solution for dissolving the nitric oxide, formaldehyde impurities in this gas stream before being piped to the engine air intake for re-combustion, thereby reducing the engine's exhaust pollution and improving its fuel economy. The combustible, heavier pollutants from the second separation stage are piped to air filter assemblies. This gas stream convoluting at a high-speed through the top stator-vanes of the air filters, centrifugally separates the coalescent water, aldehydes, nitrogen dioxides, sulfates, sulfur, lead particles which collect at the bottom of the bowl, wherein it is periodically released to the roadway. Whereas, the heavier hydrocarbon, carbon particles are piped through the air filter's porous element to the engine air intake for re-combustion, further reducing the engine's exhaust pollution and improving its fuel economy.

A Rechargeable Li-Air Fuel Cell Battery Based on Garnet Solid Electrolytes.

Science.gov (United States)

Sun, Jiyang; Zhao, Ning; Li, Yiqiu; Guo, Xiangxin; Feng, Xuefei; Liu, Xiaosong; Liu, Zhi; Cui, Guanglei; Zheng, Hao; Gu, Lin; Li, Hong

2017-01-24

Non-aqueous Li-air batteries have been intensively studied in the past few years for their theoretically super-high energy density. However, they cannot operate properly in real air because they contain highly unstable and volatile electrolytes. Here, we report the fabrication of solid-state Li-air batteries using garnet (i.e., Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 , LLZTO) ceramic disks with high density and ionic conductivity as the electrolytes and composite cathodes consisting of garnet powder, Li salts (LiTFSI) and active carbon. These batteries run in real air based on the formation and decomposition at least partially of Li 2 CO 3 . Batteries with LiTFSI mixed with polyimide (PI:LiTFSI) as a binder show rechargeability at 200 °C with a specific capacity of 2184 mAh g -1 carbon at 20 μA cm -2 . Replacement of PI:LiTFSI with LiTFSI dissolved in polypropylene carbonate (PPC:LiTFSI) reduces interfacial resistance, and the resulting batteries show a greatly increased discharge capacity of approximately 20300 mAh g -1 carbon and cycle 50 times while maintaining a cutoff capacity of 1000 mAh g -1 carbon at 20 μA cm -2 and 80 °C. These results demonstrate that the use of LLZTO ceramic electrolytes enables operation of the Li-air battery in real air at medium temperatures, leading to a novel type of Li-air fuel cell battery for energy storage.

Means of decreasing air pollution in towns by fuel combustion products

Energy Technology Data Exchange (ETDEWEB)

Styrikovich, M A; Minaev, E V; Troitskii, A A; Vnukov, A K

1976-01-01

The main sources of pollution of city air by CO, SO/sub 2/ and NO/sub 2/ are stationary and mobile plants consuming fossil fuel for power generting and manufacturing purposes. The participation of individual sources and of branches of industry in the formation of the general background of pollutant concentration in the air of the city is not directly related to the mass of pollutant emissions by these sources. In particular, for the considered city the power stations and heating plants contribute only a few percent of the average background with respect to SO/sub 2/ and NO/sub 2/ and take virtually no part in the formation of the background CO. The effectiveness of equal investments in gas cleaning in the different branches of the municipal economy with regard to improving the general background of city air pollution can differ by a very great amount. In this connection the planning of measures for reducing the background should be carried out by means of interdepartmental optimization of sizes and distribution of investment between plants. Figures are given and the procedures are used of an evaluating nature are regarded as initial premises for the formulation of appropriate detailed investigations.

Emission factors of air pollutants from CNG-gasoline bi-fuel vehicles: Part I. Black carbon.

Science.gov (United States)

Wang, Yang; Xing, Zhenyu; Xu, Hui; Du, Ke

2016-12-01

Compressed natural gas (CNG) is considered to be a "cleaner" fuel compared to other fossil fuels. Therefore, it is used as an alternative fuel in motor vehicles to reduce emissions of air pollutants in transportation. To quantify "how clean" burning CNG is compared to burning gasoline, quantification of pollutant emissions under the same driving conditions for motor vehicles with different fuels is needed. In this study, a fleet of bi-fuel vehicles was selected to measure the emissions of black carbon (BC), carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NO x ) for driving in CNG mode and gasoline mode respectively under the same set of constant speeds and accelerations. Comparison of emission factors (EFs) for the vehicles burning CNG and gasoline are discussed. This part of the paper series reports BC EFs for bi-fuel vehicles driving on the real road, which were measured using an in situ method. Our results show that burning CNG will lead to 54%-83% reduction in BC emissions per kilometer, depending on actual driving conditions. These comparisons show that CNG is a cleaner fuel than gasoline for motor vehicles in terms of BC emissions and provide a viable option for reducing BC emissions cause by transportation. Copyright © 2016 Elsevier B.V. All rights reserved.

40 CFR 80.602 - What records must be kept by entities in the NRLM diesel fuel, ECA marine fuel, and diesel fuel...

Science.gov (United States)

2010-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel Recordkeeping and Reporting Requirements... in the NRLM diesel fuel, ECA marine fuel, and diesel fuel additive production, importation, and...

Castor oil biodiesel as an alternative fuel for diesel engines

International Nuclear Information System (INIS)

Benavides, Alirio; Benjumea, Pedro; Pashova, Veselina

2007-01-01

In this paper, a study related to the production and use of castor oil biodiesel is presented. The maximum methyl esters yield of the castor oil transesterification reaction is obtained under the following conditions: ambient temperature, a molar ratio of methanol to vegetable oil equal to 9 and a catalyst percentage equal to 0.8%. The castor oil biodiesel can be blended with petroleum diesel as far as 15% in such way that the resulting blend complies with national and international technical standards for diesel fuels. Its high viscosity becomes the main difficulty for using castor oil biodiesel in engines. However this biofuel exhibits excellent cold flow properties (low values of cloud and pour points). The motor tests using castor oil biodiesel petroleum diesel blends, for the biodiesel proportion tested; show that a biodiesel percentage increase leads to an increase in the specific fuel consumption, a decrease in the fuel air ratio, a slight decrease in smoke opacity, while the fuel conversion efficiency and the CO and CO 2 emissions practically remain constants

Experimental study on occurrence-time ratio measurements of air entrainment in a suction sump

International Nuclear Information System (INIS)

Inagaki, K; Funaki, J; Hirata, K

2009-01-01

In order to get accurate measurements of air entrainment in a suction sump, we design some new simple bubble sensors, which can detect the existence of air bubbles inside a suction pipe with no disturbances by the sensors and with a fine spatial resolution. We force on an intermittency factor γ, that is, an occurrence-time ratio of the air entrainment, and compare the result by the present sensor with those by conventional two methods; namely, visual and auditory ones. As a result, we show the criteria which specify lower-accuracy conditions in the conventional methods. By the visual method, the accuracy of the γ becomes low, when γ is less than 0.05. By the auditory method, the accuracy of γ becomes low, when the submergence depth S of the suction pipe is close to the critical one S c .

Thermodynamic Analyses of Biomass Gasification Integrated Externally Fired, Post-Firing and Dual-Fuel Combined Cycles

Directory of Open Access Journals (Sweden)

Saeed Soltani

2015-01-01

Full Text Available In the present work, the results are reported of the energy and exergy analyses of three biomass-related processes for electricity generation: the biomass gasification integrated externally fired combined cycle, the biomass gasification integrated dual-fuel combined cycle, and the biomass gasification integrated post-firing combined cycle. The energy efficiency for the biomass gasification integrated post-firing combined cycle is 3% to 6% points higher than for the other cycles. Although the efficiency of the externally fired biomass combined cycle is the lowest, it has an advantage in that it only uses biomass. The energy and exergy efficiencies are maximized for the three configurations at particular values of compressor pressure ratios, and increase with gas turbine inlet temperature. As pressure ratio increases, the mass of air per mass of steam decreases for the biomass gasification integrated post-firing combined cycle, but the pressure ratio has little influence on the ratio of mass of air per mass of steam for the other cycles. The gas turbine exergy efficiency is the highest for the three configurations. The combustion chamber for the dual-fuel cycle exhibits the highest exergy efficiency and that for the post-firing cycle the lowest. Another benefit of the biomass gasification integrated externally fired combined cycle is that it exhibits the highest air preheater and heat recovery steam generator exergy efficiencies.

Sodium-cooled Fast Reactor Cores using Uranium-Free Metallic Fuels for Maximizing TRU Support Ratio

International Nuclear Information System (INIS)

You, WuSeung; Hong, Ser Gi

2014-01-01

The depleted uranium plays important roles in the SFR burner cores because it substantially contributes to the inherent safety of the core through the negative Doppler coefficient and large delayed neutron. However, the use of depleted uranium as a diluent nuclide leads to a limited value of TRU support ratio due to the generation of TRUs through the breeding. In this paper, we designed sodium cooled fast reactor (SFR) cores having uranium-free fuels 3,4 for maximization of TRU consumption rate. However, the uranium-free fuelled burner cores can be penalized by unacceptably small values of the Doppler coefficient and small delayed neutron fraction. In this work, metallic fuels of TRU-(W or Ni)-Zr are considered to improve the performances of the uranium-free cores. The objective of this work is to consistently compare the neutronic performances of uranium-free sodium cooled fast reactor cores having TRU-Zr metallic fuels added with Ni or W and also to clarify what are the problematic features to be resolved. In this paper, a consistent comparative study of 400MWe sodium cooled burner cores having uranium-based fuels and uranium-free fuels was done to analyze the relative core neutronic features. Also, we proposed a uranium-free metallic fuel based on Nickel. From the results, it is found that tungsten-based uranium-free metallic fuel gives large negative Doppler coefficient due to high resonance of tungsten isotopes but this core has large sodium void worth and small effective delayed neutron fraction while the nickel-based uranium-free metallic fuelled core has less negative Doppler coefficient but smaller sodium void worth and larger effective delayed neutron fraction than the tungsten-based one. On the other hand, the core having TRU-Zr has very high burnup reactivity swing which may be problematic in compensating it using control rods and the least negative Doppler coefficient

Thermodynamic Cycle and CFD Analyses for Hydrogen Fueled Air-breathing Pulse Detonation Engines

Science.gov (United States)

Povinelli, Louis A.; Yungster, Shaye

2002-01-01

This paper presents the results of a thermodynamic cycle analysis of a pulse detonation engine (PDE) using a hydrogen-air mixture at static conditions. The cycle performance results, namely the specific thrust, fuel consumption and impulse are compared to a single cycle CFD analysis for a detonation tube which considers finite rate chemistry. The differences in the impulse values were indicative of the additional performance potential attainable in a PDE.

Fuel consumption in an air blower for agricultural use under different operating conditions

OpenAIRE

Silva, Robson L. da

2017-01-01

ABSTRACT Evaluation of fuel consumption in internal combustion engines (ICE) of agricultural machinery and equipment is important in determining the performance under various operating conditions, especially when using biofuels. This study consisted of experimental evaluation of the gasoline (petrol)/ethanol consumption in a two-stroke 1-cylinder ICE, Otto cycle, functioning as an air blower for agriculture and related applications. A methodology for tests of non-automotive ICE, based on ABNT...

The relationship between air pollution, fossil fuel energy consumption, and water resources in the panel of selected Asia-Pacific countries.

Science.gov (United States)

Rafindadi, Abdulkadir Abdulrashid; Yusof, Zarinah; Zaman, Khalid; Kyophilavong, Phouphet; Akhmat, Ghulam

2014-10-01

The objective of the study is to examine the relationship between air pollution, fossil fuel energy consumption, water resources, and natural resource rents in the panel of selected Asia-Pacific countries, over a period of 1975-2012. The study includes number of variables in the model for robust analysis. The results of cross-sectional analysis show that there is a significant relationship between air pollution, energy consumption, and water productivity in the individual countries of Asia-Pacific. However, the results of each country vary according to the time invariant shocks. For this purpose, the study employed the panel least square technique which includes the panel least square regression, panel fixed effect regression, and panel two-stage least square regression. In general, all the panel tests indicate that there is a significant and positive relationship between air pollution, energy consumption, and water resources in the region. The fossil fuel energy consumption has a major dominating impact on the changes in the air pollution in the region.

Effect of filling ratio on premixed methane/air explosion in an open-end pipe

Directory of Open Access Journals (Sweden)

Chang Guo

2016-06-01

Full Text Available The propagation characteristics of premixed methane/air explosion under different filling ratios (20%, 30%, 40%, 50%, 60%, and 100% were studied using an experimental system. The results indicate that the peak overpressure showed a decreasing trend at the initial stage but then showed an increasing trend until reaching its maximum value under different filling ratios. As the explosion propagated to the open end, the overpressure showed a downtrend. At this point, the flame speed initially increased along the pipe but then dropped dramatically. In addition, the explosion overpressure and flame speed increased with the increase of filling ratio. However, when the filling ratio reached 50%, the explosion overpressure and flame speed tended to be stable and the increase was not obvious. These results will be of great importance in evaluating the explosive damage to equipment and human personnel working in coal mines or other chemical industries.

Optimal fault-tolerant control strategy of a solid oxide fuel cell system

Science.gov (United States)

Wu, Xiaojuan; Gao, Danhui

2017-10-01

For solid oxide fuel cell (SOFC) development, load tracking, heat management, air excess ratio constraint, high efficiency, low cost and fault diagnosis are six key issues. However, no literature studies the control techniques combining optimization and fault diagnosis for the SOFC system. An optimal fault-tolerant control strategy is presented in this paper, which involves four parts: a fault diagnosis module, a switching module, two backup optimizers and a controller loop. The fault diagnosis part is presented to identify the SOFC current fault type, and the switching module is used to select the appropriate backup optimizer based on the diagnosis result. NSGA-II and TOPSIS are employed to design the two backup optimizers under normal and air compressor fault states. PID algorithm is proposed to design the control loop, which includes a power tracking controller, an anode inlet temperature controller, a cathode inlet temperature controller and an air excess ratio controller. The simulation results show the proposed optimal fault-tolerant control method can track the power, temperature and air excess ratio at the desired values, simultaneously achieving the maximum efficiency and the minimum unit cost in the case of SOFC normal and even in the air compressor fault.

Oxidation of Alkane Rich Gasoline Fuels and their Surrogates in a Motored Engine

KAUST Repository

Shankar, Vijai S B

2015-03-30

The validation of surrogates formulated using a computational framework by Ahmed et al.[1]for two purely paraffinic gasoline fuels labelled FACE A and FACE C was undertaken in this study. The ability of these surrogate mixtures to be used in modelling LTC engines was accessed by comparison of their low temperature oxidation chemistry with that of the respective parent fuel as well as a PRF based on RON. This was done by testing the surrogate mixtures in a modified Cooperative Fuels Research (CFR) engine running in Controlled Autoignition Mode (CAI) mode. The engine was run at a constant speed of 600 rpm at an equivalence ratio of 0.5 with the intake temperature at 150 °C and a pressure of 98 kPa. The low temperature reactivity of the fuels were studied by varying the compression ratio of the engine from the point were very only small low temperature heat release was observed to a point beyond which auto-ignition of the fuel/air mixture occurred. The apparent heat release rates of different fuels was calculated from the pressure histories using first law analysis and the CA 50 times of the low temperature heat release (LTHR) were compared. The surrogates reproduced the cool flame behavior of the parent fuels better than the PRF across all compression ratios.

Oxidation of Alkane Rich Gasoline Fuels and their Surrogates in a Motored Engine

KAUST Repository

Shankar, Vijai S B; Al-Qurashi, Khalid; Ahmed, Ahfaz; Atef, Nour; Chung, Suk-Ho; Roberts, William L.; Sarathy, Mani

2015-01-01

The validation of surrogates formulated using a computational framework by Ahmed et al.[1]for two purely paraffinic gasoline fuels labelled FACE A and FACE C was undertaken in this study. The ability of these surrogate mixtures to be used in modelling LTC engines was accessed by comparison of their low temperature oxidation chemistry with that of the respective parent fuel as well as a PRF based on RON. This was done by testing the surrogate mixtures in a modified Cooperative Fuels Research (CFR) engine running in Controlled Autoignition Mode (CAI) mode. The engine was run at a constant speed of 600 rpm at an equivalence ratio of 0.5 with the intake temperature at 150 °C and a pressure of 98 kPa. The low temperature reactivity of the fuels were studied by varying the compression ratio of the engine from the point were very only small low temperature heat release was observed to a point beyond which auto-ignition of the fuel/air mixture occurred. The apparent heat release rates of different fuels was calculated from the pressure histories using first law analysis and the CA 50 times of the low temperature heat release (LTHR) were compared. The surrogates reproduced the cool flame behavior of the parent fuels better than the PRF across all compression ratios.

Recent decreases in fossil-fuel emissions of ethane and methane derived from firn air.

Science.gov (United States)

Aydin, Murat; Verhulst, Kristal R; Saltzman, Eric S; Battle, Mark O; Montzka, Stephen A; Blake, Donald R; Tang, Qi; Prather, Michael J

2011-08-10

Methane and ethane are the most abundant hydrocarbons in the atmosphere and they affect both atmospheric chemistry and climate. Both gases are emitted from fossil fuels and biomass burning, whereas methane (CH(4)) alone has large sources from wetlands, agriculture, landfills and waste water. Here we use measurements in firn (perennial snowpack) air from Greenland and Antarctica to reconstruct the atmospheric variability of ethane (C(2)H(6)) during the twentieth century. Ethane levels rose from early in the century until the 1980s, when the trend reversed, with a period of decline over the next 20 years. We find that this variability was primarily driven by changes in ethane emissions from fossil fuels; these emissions peaked in the 1960s and 1970s at 14-16 teragrams per year (1 Tg = 10(12) g) and dropped to 8-10 Tg  yr(-1) by the turn of the century. The reduction in fossil-fuel sources is probably related to changes in light hydrocarbon emissions associated with petroleum production and use. The ethane-based fossil-fuel emission history is strikingly different from bottom-up estimates of methane emissions from fossil-fuel use, and implies that the fossil-fuel source of methane started to decline in the 1980s and probably caused the late twentieth century slow-down in the growth rate of atmospheric methane.

Research of power fuel low-temperature vortex combustion in industrial boiler based on numerical modelling

Directory of Open Access Journals (Sweden)

Orlova K.Y.

2017-01-01

Full Text Available The goal of the presented research is to perform numerical modelling of fuel low-temperature vortex combustion in once-through industrial steam boiler. Full size and scaled-down furnace model created with FIRE 3D software and was used for the research. All geometrical features were observed. The baseline information for the low-temperature vortex furnace process are velocity and temperature of low, upper and burner blast, air-fuel ratio, fuel consumption, coal dust size range. The obtained results are: temperature and velocity three dimensional fields, furnace gases and solid fuel ash particles concentration.

The effect of water injection on nitric oxide emissions of a gas turbine combustor burning ASTM Jet-A fuel

Science.gov (United States)

Marchionna, N. R.; Diehl, L. A.; Trout, A. M.

1973-01-01

Tests were conducted to determine the effect of water injection on oxides of nitrogen (NOx) emissions of a full annular, ram induction gas turbine combustor burning ASTM Jet-A fuel. The combustor was operated at conditions simulating sea-level takeoff and cruise conditions. Water at ambient temperature was injected into the combustor primary zone at water-fuel ratios up to 2. At an inlet-air temperature of 589 K (600 F) water injection decreased the NOx emission index at a constant exponential rate: NOx = NOx (o) e to the -15 W/F power (where W/F is the water-fuel ratio and NOx(o) indicates the value with no injection). The effect of increasing combustor inlet-air temperature was to decrease the effect of the water injection. Other operating variables such as pressure and reference Mach number did not appear to significantly affect the percent reduction in NOx. Smoke emissions were found to decrease with increasing water injection.

Reforming performance of a plasma-catalyst hybrid converter using low carbon fuels

International Nuclear Information System (INIS)

Horng, R.-F.; Lai, M.-P.; Huang, H.-H.; Chang, Y.-P.

2009-01-01

The reforming performance of a plasma-catalyst hybrid converter using different low carbon fuels was investigated. The methodology was to use arc from spark discharge combined with an appropriate oxygen/carbon molar ratio (O 2 /C) and feeding rate of the supplied mixture. To enhance the mixing and reforming reaction, a gas intake swirl was generated by inducing the mixture tangentially into the reaction chamber. The required energy for fuel processing was provided by heat released through the oxidation of the air-fuel mixture. The reforming temperature as well as the effect of steam addition on the hydrogen production was studied. The results showed that reformate gas temperature had a profound effect on the overall reaction. The H 2 /(CO + CO 2 ) ratio reformed by both methane and propane was shown to increase with temperature and that the optimum ratio was obtained when reforming methane under 650 deg. C. The conversion efficiency of the fuel was also shown to increase with increasing temperature. The best thermal efficiency of 72.01% was obtained near 750 deg. C. The theoretical equilibrium calculations and the experimental results were compared.

Role of Fluid-Dynamics in Soot Formation and Microstructure in Acetylene-Air Laminar Diffusion Flames

Directory of Open Access Journals (Sweden)

Praveen Pandey

2015-03-01

Full Text Available Residence time and thermo-chemical environment are important factors in the soot-formation process in flames. Studies have revealed that flow-dynamics plays a dominant role in soot formation process. For understanding the effect of flow dynamics on soot formation and physical structure of the soot formed in different combustion environments two types of laminar diffusion flames of Acetylene and air, a normal diffusion flame (NDF and an inverse diffusion flame (IDF have been investigated. The fuel and air supply in the reaction zone in two flame types were kept constant but the interchange of relative position of fuel and air altered the burner exit Reynolds and Froude numbers of gases, fuel/air velocity ratio and flame shape. Soot samples were collected using thermophoretic sampling on transmission electron microscope (TEM grids at different flame heights and were analyzed off-line in a Transmission Electron Microscope. Soot primary particle size, soot aggregate size and soot volume fraction were measured using an image analysis software. In NDF the maximum flame temperature was about 1525 K and 1230 K for IDF. The soot primary particles are distinctly smaller in size in IDF (between 19 – 26 nm compared to NDF (between 29–34 nm. Both NDF and IDF show chainlike branched structure of soot agglomerate with soot particles of a nearly spherical shape. The average number of soot primary particles per aggregate in NDF was in the range of 24 to 40 and in IDF it varied between 16 to 24. Soot volume fraction was between 0.6 to 1.5 ppm in NDF where as it was less than 0.2 ppm in IDF. The change in sooting characteristics of the two flame types is attributed to changed fuel/air velocity ratio, entrainment of gas molecules and thermophoresis on soot particles.

Flame kernel characterization of laser ignition of natural gas-air mixture in a constant volume combustion chamber

Science.gov (United States)

Srivastava, Dhananjay Kumar; Dharamshi, Kewal; Agarwal, Avinash Kumar

2011-09-01

In this paper, laser-induced ignition was investigated for compressed natural gas-air mixtures. Experiments were performed in a constant volume combustion chamber, which simulate end of the compression stroke conditions of a SI engine. This chamber simulates the engine combustion chamber conditions except turbulence of air-fuel mixture. It has four optical windows at diametrically opposite locations, which are used for laser ignition and optical diagnostics simultaneously. All experiments were conducted at 10 bar chamber pressure and 373 K chamber temperature. Initial stage of combustion phenomena was visualized by employing Shadowgraphy technique using a high speed CMOS camera. Flame kernel development of the combustible fuel-air mixture was investigated under different relative air-fuel ratios ( λ=1.2-1.7) and the images were interrogated for temporal propagation of flame front. Pressure-time history inside the combustion chamber was recorded and analyzed. This data is useful in characterizing the laser ignition of natural gas-air mixture and can be used in developing an appropriate laser ignition system for commercial use in SI engines.

Sulphur capture by co-firing sulphur containing fuels with biomass fuels - optimization

International Nuclear Information System (INIS)

Nordin, A.

1992-12-01

Previous results concerning co-firing of high sulphur fuels with biomass fuels have shown that a significant part of the sulphur can be absorbed in the ash by formation of harmless sulphates. The aim of this work has been to (i) determine the maximum reduction that can be obtained in a bench scaled fluidized bed (5 kW); (ii) determine which operating conditions will give maximum reduction; (iii) point out the importance and applicability of experimental designs and multivariate methods when optimizing combustion processes; (iv) determine if the degree of sulphur capture can be correlated to the degree of slagging, fouling or bed sintering; and (v) determine if further studies are desired. The following are some of the more important results obtained: - By co-firing peat with biomass, a total sulphur retention of 70 % can be obtained. By co-firing coal with energy-grass, the total SO 2 emissions can be reduced by 90 %. - Fuel feeding rate, amount of combustion air and the primary air ratio were the most important operating parameters for the reduction. Bed temperature and oxygen level seem to be the crucial physical parameters. - The NO emissions also decreased by the sulphur reducing measures. The CO emissions were relatively high (130 mg/MJ) compared to large scale facilities due to the small reactor and the small fluctuations in the fuel feeding rate. The SO 2 emissions could however be reduced without any increase in CO emissions. - When the reactor was fired with a grass, the bed sintered at a low temperature ( 2 SO 4 and KCl are formed no sintering problems were observed. (27 refs., 41 figs., 9 tabs., 3 appendices)

Improving of diesel combustion-pollution-fuel economy and performance by gasoline fumigation

International Nuclear Information System (INIS)

Şahin, Zehra; Durgun, Orhan

2013-01-01

Highlights: • The effects of gasoline fumigation on the engine performance and NO x emission were investigated in Ford XLD 418 T automotive diesel engine. • Gasoline at approximately (2, 4, 6, 8 10, and 12)% (by vol.) ratios was injected into intake air by a carburetor. • GF enhances effective power and reduces brake specific fuel consumption, cost, and NO x emission. - Abstract: One of the most important objectives of the studies worldwide is to improve combustion of diesel engine to meet growing energy needs and to reduce increasing environmental pollution. To accomplish this goal, especially to reduce pollutant emissions, researchers have focused their interest on the field of alternative fuels and alternative solutions. Gasoline fumigation (GF) is one of these alternative solutions, by which diesel combustion, fuel economy, and engine performance are improved, and environmental pollution is decreased. In the fumigation method, gasoline is injected into intake air, either by a carburetor, which main nozzle section is adjustable or by a simple injection system. In the present experimental study, a simple carburetor was used, and the effects of gasoline fumigation at (2, 4, 6, 8, 10, 12)% (by vol.) gasoline ratios on the combustion, NO x emission, fuel economy, and engine performance sophisticatedly investigated for a fully instrumented, four-cylinder, water-cooled indirect injection (IDI), Ford XLD 418 T automotive diesel engine. Tests were conducted for each of the above gasoline fumigation ratios at three different speeds and for (1/1, 3/4, and 1/2) fuel delivery ratios (FDRs). GF test results showed that NO x emission is lower than that of neat diesel fuel (NDF). NO x emission decreases approximately 4.20%, 2.50%, and 9.65% for (1/1, 3/4, and 1/2) FDRs, respectively. Effective power increases approximately 2.38% for 1/1 FDR. At (2500 and 3000) rpms, effective power decreases at low gasoline ratios, but it increases at high gasoline ratios for 3/4 and 1

Volatile organic compound mixing ratios above Beijing in November and December 2016

Science.gov (United States)

Acton, William; Shaw, Marvin; Huang, Zhonghui; Wang, Zhaoyi; Wang, Xinming; Zhang, Yanli; Davison, Brian; Langford, Ben; Mullinger, Neil; Nemitz, Eiko; Fu, Pingqing; Squires, Freya; Carpenter, Lucy; Lewis, Alastair; Hewitt, Nick

2017-04-01

Volatile organic compounds (VOCs) are emitted into the atmosphere from vegetation and anthropogenic sources such as fossil fuel combustion, biomass burning and the evaporation of petroleum products. These compounds play an important role in the chemistry of the lower atmosphere through secondary organic aerosol (SOA) formation and facilitating the formation of tropospheric ozone. As well as their indirect impact on human health via the formation of ozone and SOA, some VOCs, including benzene, directly affect human health adversely. Here we report VOC mixing ratios measured in Beijing during a 5 week intensive field campaign from the 7th November to the 10th December 2016. This work was carried out as part of the Sources and Emissions of Air Pollutants in Beijing (AIRPOLL-Beijing) work project within the Air Pollution and Human Health in a Developing Megacity (APHH-Beijing) research programme. APHH is a large multi-institutional study which aims to record the concentrations and identify the sources of urban air pollutants in Beijing, determine exposure, understand their effects on human health, and to identify solutions. VOC mixing ratios were recorded using a Proton Transfer Reaction-Time of Flight-Mass Spectrometer (PTR-ToF-MS, Ionicon Analytik) and a Selected Ion Flow Tube-Mass Spectrometer (SIFT-MS, SYFT Technologies). During the measurement period Beijing was subject to multiple pollution events that alternated with periods of relatively good air quality, allowing the VOCs within the polluted air masses to be identified and quantified. VOCs were sampled at 102 m with additional gradient measurements made at 3, 15, 32 and 64 m providing a vertical profile of VOC mixing ratios. Mixing ratios of methanol, acetonitrile, acetaldehyde, acetone, isoprene and aromatics species will be reported together with a discussion of potential sources. Comparisons will then be drawn with other large cities.

NOx reduction using biomass as reburning fuel

Energy Technology Data Exchange (ETDEWEB)

Niu Sheng-li; Lu Chun-mei; Gao Pan; Han Kui-hua; Geng Ping; Cheng Zhong-jie [Shandong University, Jinan (China). School of Energy and Power Engineering

2008-10-15

A series of experiments were conducted in a multiple-functional combustion test bed with several kinds of biomass as reburning fuel to reduce NOx. The character and experimental parameters are, emphasized to examine the influences on NOx reduction. The results show that biomass could get about 55% to 70% NOx reduction. Within a certain range of the parameters tested, NOx reduction increases with the increasing temperature of reburning zone and initial concentration of NOx and with decreasing excess air ratio and diameter of fuel particle. Under the same test conditions, cornstalk gets the highest NOx reduction and wheat straw, peanut shell, wood chip follow in turn. 14 refs., 7 figs., 1 tab.

Jatropha oil and biogas in a dual fuel CI engine for rural electrification

NARCIS (Netherlands)

Luijten, C.C.M.; Kerkhof, E.

2011-01-01

This work presents the first dual fuel measurements with pure jatropha oil and biogas, using a 12 kW diesel engine generator. Reference tests are done with pure jatropha oil and with diesel to characterize the engine’s thermal efficiency eta_t, volumetric efficiency eta_v and air excess ratio lambda

CFD Analysis on the Passive Heat Removal by Helium and Air in the Canister of Spent Fuel Dry Storage System

Energy Technology Data Exchange (ETDEWEB)

Shin, Do Young; Jeong, Ui Ju; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

2016-05-15

In the current commercial design, the canister of the dry storage system is mainly backfilled with helium gas. Helium gas shows very conductive behavior due to high thermal conductivity and small density change with temperature. However, other gases such as air, argon, or nitrogen are expected to show effective convective behavior. Thus these are also considered as candidates for the backfill gas to provide effective coolability. In this study, to compare the dominant cooling mechanism and effectiveness of cooling between helium gas and air, a computational fluid dynamics (CFD) analysis for the canister of spent fuel dry storage system with backfill gas of helium and air is carried out. In this study, CFD simulations for the helium and air backfilled gas for dry storage system canister were carried out using ANSYS FLUENT code. For the comparison work, two backfilled fluids were modeled with same initial and boundary conditions. The observed major difference can be summarized as follows. - The simulation results showed the difference in dominant heat removal mechanism. Conduction for helium, and convection for air considering Reynolds number distribution. - The temperature gradient inside the fuel assembly showed that in case of air, more effective heat mixing occurred compared to helium.

Spatial distribution of bacterial communities on volumetric and planar anodes in single-chamber air-cathode microbial fuel cells

KAUST Repository

Vargas, Ignacio T.; Albert, Istvan U.; Regan, John M.

2013-01-01

Pyrosequencing was used to characterize bacterial communities in air-cathode microbial fuel cells across a volumetric (graphite fiber brush) and a planar (carbon cloth) anode, where different physical and chemical gradients would be expected

Ignition of alkane-rich FACE gasoline fuels and their surrogate mixtures

KAUST Repository

Sarathy, Mani

2015-01-01

Petroleum derived gasoline is the most used transportation fuel for light-duty vehicles. In order to better understand gasoline combustion, this study investigated the ignition propensity of two alkane-rich FACE (Fuels for Advanced Combustion Engines) gasoline test fuels and their corresponding PRF (primary reference fuel) blend in fundamental combustion experiments. Shock tube ignition delay times were measured in two separate facilities at pressures of 10, 20, and 40 bar, temperatures from 715 to 1500 K, and two equivalence ratios. Rapid compression machine ignition delay times were measured for fuel/air mixtures at pressures of 20 and 40 bar, temperatures from 632 to 745 K, and two equivalence ratios. Detailed hydrocarbon analysis was also performed on the FACE gasoline fuels, and the results were used to formulate multi-component gasoline surrogate mixtures. Detailed chemical kinetic modeling results are presented herein to provide insights into the relevance of utilizing PRF and multi-component surrogate mixtures to reproduce the ignition behavior of the alkane-rich FACE gasoline fuels. The two FACE gasoline fuels and their corresponding PRF mixture displayed similar ignition behavior at intermediate and high temperatures, but differences were observed at low temperatures. These trends were mimicked by corresponding surrogate mixture models, except for the amount of heat release in the first stage of a two-stage ignition events, when observed. © 2014 The Combustion Institute.

Fuel assembly

International Nuclear Information System (INIS)

Sano, Hiroki; Fushimi, Atsushi; Tominaga, Kenji; Aoyama, Motoo; Ishii, Kazuya.

1997-01-01

In burnable poison-incorporated uranium fuels of a BWR type reactor, the compositional ratio of isotopes of the burnable poisons is changed so as to increase the amount of those having a large neutron absorbing cross sectional area. For example, if the ratio of Gd-157 at the same burnable poison enrichment degree is made greater than the natural ratio, this gives the same effect as the increase of the enrichment degree per one fuel rod, thereby providing an effect of reducing a surplus reactivity. Gadolinium, hafnium and europium as burnable poisons have an absorbing cross sectional area being greater in odd numbered nuclei than in even numbered nuclei, on the contrary, boron has a cross section being greater in even numbered nucleus than odd numbered nuclei. Accordingly, if the ratio of isotopes having greater cross section at the same burnable poison enrichment degree is made greater than the natural ratio, surplus reactivity at the initial stage of the burning can be reduced without greatly increasing the amount of burnable poison-incorporated uranium fuels, fuel loading amount is not reduced and the fuel economy is not worsened. (N.H.)

Numerical Study on the Performance Characteristics of Hydrogen Fueled Port Injection Internal Combustion Engine

OpenAIRE

Rosli A. Bakar; Mohammed K. Mohammed; M. M. Rahman

2009-01-01

This study was focused on the engine performance of single cylinder hydrogen fueled port injection internal combustion engine. GT-Power was utilized to develop the model for port injection engine. One dimensional gas dynamics was represented the flow and heat transfer in the components of the engine model. The governing equations were introduced first, followed by the performance parameters and model description. Air-fuel ratio was varied from stoichiometric limit to a lean limit and the rota...

Determination of curie content and 134/137cesium ratios by gamma spectroscopy of high burnup plutonium-aluminum fuel assemblies

International Nuclear Information System (INIS)

Haggard, D.L.; Tanner, J.E.

1997-06-01

Nondestructive assay (NDA) gamma spectroscopy techniques were used to measure 134/137 Cs ratios on nine PuAl Mark 42 fuel assemblies. The purpose of the ratio measurement was to confirm theoretical burnup calculations. 134/137 Cs ratios were determined from the measured activity based on corrected net peak area counts for the 605 keV peak from 134 Cs and the 662 keV peak from 137 Cs/ 137m Ba. Assembly No. 2 134/137 Cs ratio measured on 4-15-92 was 0.19. The measured 134/137 Cs ratio was decay corrected to be 2.11 on 8-1-84 based on the half lives of 134 Cs and 137 Cs. The measured 134/137 Cs ratio range was 1.90--2.14 for all nine assemblies. These measured values compare to a theoretical ratio of 1.7 on 8-1-84 determined by burnup calculations. Total cesium curie content was also requested and determined using the NDA direct measurements. Gamma spectral data were measured on the nine sectioned Mark 42 fuel assemblies. Measured cesium curie content, decay corrected to 8-1-84, ranged from 18170--24480 curies of 134 Cs and 8620--11646 curies of 137 Cs. Theoretical cesium curie content of 8-1-84 was 15200 curies 134 Cs and 8973 curies 137 Cs. Direct assay cesium ratio is 12% to 26% higher than the predicted ratio of 1.7. The measured 134 Cs data indicate between 20%--61% more activity than that predicted by the burnup code, whereas the measured 137 Cs activity is between 4% less to 30% more than the predicted activity. This information may be used to address issues concerning criticality safety, storage, and shipping of this type of material

Air pollution and urban air quality management in Indonesia

Energy Technology Data Exchange (ETDEWEB)

Santosa, Sri J. [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Gadjah Mada University, Yogyakarta (Indonesia); Okuda, Tomoaki; Tanaka, Shigeru [Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama (Japan)

2008-06-15

The trade-led industry and economic development after the Asian financial crisis a decade ago has been accelerated in Indonesia to improve the quality of life of its population. This rapid development of Indonesia was in fact heavily fueled by fossil fuels, especially oil, followed by natural gas and coal. The exploitation of fossil fuel in fueling the development resulted in significant environmental quality degradation. Air pollution is perhaps Indonesia's most severe environmental problem. Industry and transportation were the typical main sources of urban air pollutants. Moreover, Indonesia also failed to reach its original 2005 target for a complete phase-out of leaded gasoline. As a result, the level of Pb together with other pollutants such as CO, NO{sub x}, SO{sub 2}, and total suspended particulates has exceeded or at least approached the designated ambient air quality standards. The urban air pollution will not be lesser in extent, but surely will be more severe in the future. Unfortunately, the capability of the Indonesian authorities to manage the urban air quality is still very limited and the portion of the budget allocated to the improvement of urban air quality is still remarkably low, typically 1% of total. This is why the efforts to enhance the capability to manage the urban air quality could not be handled by the environmental authorities in Indonesia's cities themselves, but outside stimulation in the form of man power, consultant and equipment assistance along with financial support has been very important. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Measurement of the Tracer Gradient and Sampling System Bias of the Hot Fuel Examination Facility Stack Air Monitoring System

Energy Technology Data Exchange (ETDEWEB)

Glissmeyer, John A.; Flaherty, Julia E.

2011-07-20

This report describes tracer gas uniformity and bias measurements made in the exhaust air discharge of the Hot Fuel Examination Facility at Idaho National Laboratory. The measurements were a follow-up on earlier measurements which indicated a lack of mixing of the two ventilation streams being discharged via a common stack. The lack of mixing is detrimental to the accuracy of air emission measurements. The lack of mixing was confirmed in these new measurements. The air sampling probe was found to be out of alignment and that was corrected. The suspected sampling bias in the air sample stream was disproved.

Factors that determine the emission of gaseous and particle pollutants for the combustion of fossil fuels

International Nuclear Information System (INIS)

Bobadilla Edgar; Gomez Elias; Ramirez Beatriz

1997-01-01

The effect of physical-chemical, kinetic, estequiometric factors and of the mixture conditions on the emissions of five main classes of pollutants produced by the combustion equipments is analyzed. The emissions of monoxide of carbon (CO) are ruled by temperature and the proportion air - fuel. The production of nitrogen oxides (NOx) is determined by operation conditions (mainly temperature) and the composition of the fuel. The oxides of sulfur (SOx) are highly influenced by the temperature; in general, the formation of SO2 is faster than the oxidation of SO3. The temperature and the degree of homogenization of the mixture are decisive in the formation of organic volatile compounds. The emission of soot and fine ashes depends basically on the temperature, ratio air - fuel and conditions of homogenization of the mixture

Panorama 2013 - Air transport and the problem of CO2: ETS mechanisms and bio-jet fuels

International Nuclear Information System (INIS)

Jean-Francois Gruson

2013-01-01

Air transport currently accounts for only 2% (∼600 Mt/year) of global CO 2 emissions from human activity. Despite this 2% level, this industry is targeted by governments - especially European Union - and initiatives targeting zero growth in carbon from 2020 onwards, and a 50% reduction by 2050. Over and above aircraft technical innovations and the way in which air traffic is organised, the introduction of ETS (Emissions Trading System) mechanisms and the development of bio-jet fuels are the options most commonly cited in discussions on how to achieve that target. (author)

Increased power to heat ratio of small scale CHP plants using biomass fuels and natural gas

International Nuclear Information System (INIS)

Savola, Tuula; Fogelholm, Carl-Johan

2006-01-01

In this paper, we present a systematic study of process changes for increased power production in 1-20 MW e combined heat and power (CHP) plants. The changes are simulated, and their economic feasibility evaluated by using existing small scale CHP case plants. Increasing power production in decentralised CHP plants that operate according to a certain heat demand could reduce the fuel consumption and CO 2 emissions per power unit produced and improve the feasibility of CHP plant investments. The CHP plant process changes were simulated under design and off design conditions and an analysis of power and heat production, investment costs and CO 2 emissions was performed over the whole annual heat demand. The results show that using biomass fuels, there are profitable possibilities to increase the current power to heat ratios, 0.23-0.48, of the small scale CHP plants up to 0.26-0.56, depending on the size of the plant. The profitable changes were a two stage district heat exchanger and the addition of a steam reheater and a feed water preheater. If natural gas is used as an additional fuel, the power to heat ratio may be increased up to 0.35-0.65 by integrating a gas engine into the process. If the CO 2 savings from the changes are also taken into account, the economic feasibility of the changes increases. The results of this work offer useful performance simulation and investment cost knowledge for the development of more efficient and economically feasible small scale CHP processes

Experimental simulation of air quality in street canyon under changes of building orientation and aspect ratio.

Science.gov (United States)

Yassin, Mohamed F; Ohba, Masaake

2012-09-01

To assist validation of numerical simulations of urban pollution, air quality in a street canyon was investigated using a wind tunnel as a research tool under neutral atmospheric conditions. We used tracer gas techniques from a line source without buoyancy. Ethylene (C(2)H(4)) was used as the tracer gas. The street canyon model was formed of six parallel building rows of the same length. The flow and dispersion field was analyzed and measured using a hot-wire anemometer with split fiber probe and fast flame ionization detector. The diffusion flow field in the boundary layer within the street canyon was examined at different locations, with varying building orientations (θ=90°, 112.5°, 135° and 157.5°) and street canyon aspect ratios (W/H=1/2, 3/4 and 1) downwind of the leeward side of the street canyon model. Results show that velocity increases with aspect ratio, and with θ>90°. Pollutant concentration increases as aspect ratio decreases. This concentration decreases exponentially in the vertical direction, and decreases as θ increases from 90°. Measured pollutant concentration distributions indicate that variability of building orientation and aspect ratio in the street canyon are important for estimating air quality in the canyon. The data presented here can be used as a comprehensive database for validation of numerical models.

Estimation of average burnup of damaged fuels loaded in Fukushima Dai-ichi reactors by using the 134Cs/137Cs ratio method