MODELING OF FUEL SPRAY CHARACTERISTICS AND DIESEL COMBUSTION CHAMBER PARAMETERS

Directory of Open Access Journals (Sweden)

G. M. Kukharonak

2011-01-01

Full Text Available The computer model for coordination of fuel spray characteristics with diesel combustion chamber parameters has been created in the paper.  The model allows to observe fuel sprays  develоpment in diesel cylinder at any moment of injection, to calculate characteristics of fuel sprays with due account of a shape and dimensions of a combustion chamber, timely to change fuel injection characteristics and supercharging parameters, shape and dimensions of a combustion chamber. Moreover the computer model permits to determine parameters of holes in an injector nozzle that provides the required fuel sprays characteristics at the stage of designing a diesel engine. Combustion chamber parameters for 4ЧН11/12.5 diesel engine have been determined in the paper.

Space shuttle orbit maneuvering engine reusable thrust chamber program

Science.gov (United States)

Senneff, J. M.

1975-01-01

Reusable thrust chamber and injector concepts were evaluated for the space shuttle orbit maneuvering engine (OME). Parametric engine calculations were carried out by computer program for N2O4/amine, LOX/amine and LOX/hydrocarbon propellant combinations for engines incorporating regenerative cooled and insulated columbium thrust chambers. The calculation methods are described including the fuel vortex film cooling method of combustion gas temperature control, and performance prediction. A method of acceptance of a regeneratively cooled heat rejection reduction using a silicone oil additive was also demonstrated by heated tube heat transfer testing. Regeneratively cooled thrust chamber operation was also demonstrated where the injector was characterized for the OME application with a channel wall regenerative thrust chamber. Bomb stability testing of the demonstration chambers/injectors demonstrated recovery for the nominal design of acoustic cavities. Cavity geometry changes were also evaluated to assess their damping margin. Performance and combustion stability was demonstrated of the originally developed 10 inch diameter combustion pattern operating in an 8 inch diameter thrust chamber.

Investigation of the cooling film distribution in liquid rocket engine

Directory of Open Access Journals (Sweden)

Luís Antonio Silva

2011-05-01

Full Text Available This study presents the results of the investigation of a cooling method widely used in the combustion chambers, which is called cooling film, and it is applied to a liquid rocket engine that uses as propellants liquid oxygen and kerosene. Starting from an engine cooling, whose film is formed through the fuel spray guns positioned on the periphery of the injection system, the film was experimentally examined, it is formed by liquid that seeped through the inner wall of the combustion chamber. The parameter used for validation and refinement of the theoretical penetration of the film was cooling, as this parameter is of paramount importance to obtain an efficient thermal protection inside the combustion chamber. Cold tests confirmed a penetrating cold enough cooling of the film for the length of the combustion chamber of the studied engine.

Molecular beam sampling from a rocket-motor combustion chamber

International Nuclear Information System (INIS)

Houseman, John; Young, W.S.

1974-01-01

A molecular-beam mass-spectrometer sampling apparatus has been developed to study the reactive species concentrations as a function of position in a rocket-motor combustion chamber. Unique design features of the sampling system include (a) the use of a multiple-nozzle end plate for preserving the nonuniform properties of the flow field inside the combustion chamber, (b) the use of a water-injection heat shield, and (c) the use of a 300 CFM mechanical pump for the first vacuum stage (eliminating the use of a huge conventional oil booster pump). Preliminary rocket-motor tests have been performed using the highly reactive propellants nitrogen tetroxide/hydrazine (N 2 O 4 /N 2 H 4 ) at an oxidizer/fuel ratio of 1.2 by weight. The combustion-chamber pressure is approximately 60psig. Qualitative results on unreacted oxidizer/fuel ratio, relative abundance of oxidizer and fuel fragments, and HN 3 distribution across the chamber are presented

Development and test of combustion chamber for Stirling engine heated by natural gas

Science.gov (United States)

Li, Tie; Song, Xiange; Gui, Xiaohong; Tang, Dawei; Li, Zhigang; Cao, Wenyu

2014-04-01

The combustion chamber is an important component for the Stirling engine heated by natural gas. In the paper, we develop a combustion chamber for the Stirling engine which aims to generate 3˜5 kWe electric power. The combustion chamber includes three main components: combustion module, heat exchange cavity and thermal head. Its feature is that the structure can divide "combustion" process and "heat transfer" process into two apparent individual steps and make them happen one by one. Since natural gas can mix with air fully before burning, the combustion process can be easily completed without the second wind. The flame can avoid contacting the thermal head of Stirling engine, and the temperature fields can be easily controlled. The designed combustion chamber is manufactured and its performance is tested by an experiment which includes two steps. The experimental result of the first step proves that the mixture of air and natural gas can be easily ignited and the flame burns stably. In the second step of experiment, the combustion heat flux can reach 20 kW, and the energy utilization efficiency of thermal head has exceeded 0.5. These test results show that the thermal performance of combustion chamber has reached the design goal. The designed combustion chamber can be applied to a real Stirling engine heated by natural gas which is to generate 3˜5 kWe electric power.

Internal combustion engine using premixed combustion of stratified charges

Science.gov (United States)

Marriott, Craig D [Rochester Hills, MI; Reitz, Rolf D [Madison, WI

2003-12-30

During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

Experience Gained from Construction of Low-Emission Combustion Chambers for On-Land Large-Capacity Gas-Turbine Units: GT24/26

Science.gov (United States)

Bulysova, L. A.; Vasil'ev, V. D.; Berne, A. L.; Gutnik, M. M.

2018-06-01

This article is the third in a planned series of articles devoted to the experience gained around the world in constructing low-emission combustion chambers for on-land large-capacity (above 250 MW) gas-turbine units (GTUs). The aim of this study is to generalize and analyze the ways in which different designers apply the fuel flow and combustion arrangement principles and the fuel feed control methods. The considered here GT24 and GT26 (GT24/26) gas-turbine units generating electric power at the 60 and 50 Hz frequencies, respectively, are fitted with burners of identical designs. Designed by ABB, these GTUs were previously manufactured by Alstom, and now they are produced by Ansaldo Energia. The efficiency of these GTUs reaches 41% at the 354 MW power output during operation in the simple cycle and 60.5% at the 505MW power output during operation in the combined cycle. Both GTUs comply with all requirements for harmful emissions. The compression ratio is equal to 35. In this article, a system is considered for two-stage fuel combustion in two sequentially arranged low-emission combustion chambers, one of which is placed upstream of the high-pressure turbine (CC1) and the other upstream of the low-pressure turbine (CC2). The article places the main focus on the CC2, which operates with a decreased content of oxygen in the oxidizer supplied to the burner inlets. The original designs of vortex generators and nozzles placed in the flow of hot combustion products going out from the high-pressure turbine are described in detail. The article also presents an original CC2 front plate cooling system, due to which a significantly smaller amount of air fed for cooling has been reached. The article also presents the pressure damping devices incorporated in the chamber, the use of which made it possible to obtain a significantly wider range of CC loads at which its low-emission operation is ensured. The fuel feed adjustment principles and the combustion control methods

Scaling of the flow field in a combustion chamber with a gas–gas injector

International Nuclear Information System (INIS)

Xiao-Wei, Wang; Guo-Biao, Cai; Ping, Jin

2010-01-01

The scaling of the flow field in a gas–gas combustion chamber is investigated theoretically, numerically and experimentally. To obtain the scaling criterion of the gas–gas combustion flowfield, formulation analysis of the three-dimensional (3D) Navier–Stokes equations for a gaseous multi-component mixing reaction flow is conducted and dimensional analysis on the gas–gas combustion phenomena is also carried out. The criterion implies that the size and the pressure of the gas–gas combustion chamber can be changed. Based on the criterion, multi-element injector chambers with different geometric sizes and at different chamber pressures ranging from 3 MPa to 20 MPa are numerically simulated. A multi-element injector chamber is designed and hot-fire tested at five chamber pressures from 1.64 MPa to 3.68 MPa. Wall temperature measurements are used to understand the similarity of combustion flowfields in the tests. The results have verified the similarities between combustion flowfields under different chamber pressures and geometries, with the criterion applied. (geophysics, astronomy and astrophysics)

Quasi-dimensional modeling of a fast-burn combustion dual-plug spark-ignition engine with complex combustion chamber geometries

International Nuclear Information System (INIS)

Altın, İsmail; Bilgin, Atilla

2015-01-01

This study builds on a previous parametric investigation using a thermodynamic-based quasi-dimensional (QD) cycle simulation of a spark-ignition (SI) engine with dual-spark plugs. The previous work examined the effects of plug-number and location on some performance parameters considering an engine with a simple cylindrical disc-shaped combustion chamber. In order to provide QD thermodynamic models applicable to complex combustion chamber geometries, a novel approach is considered here: flame-maps, which utilizes a computer aided design (CAD) software (SolidWorks). Flame maps are produced by the CAD software, which comprise all the possible flame radiuses with an increment of one-mm between them, according to the spark plug positions, spark timing, and piston position near the top dead center. The data are tabulated and stored as matrices. Then, these tabulated data are adapted to the previously reported cycle simulation. After testing for simple disc-shaped chamber geometries, the simulation is applied to a real production automobile (Honda-Fit) engine to perform the parametric study. - Highlights: • QD model was applied in dual plug engine with complex realistic combustion chamber. • This method successfully modeled the combustion in the dual-plug Honda-Fit engine. • The same combustion chamber is tested for various spark plug(s) locations. • The centrally located single spark-plug results in the fastest combustion

Spray combustion of Jet-A and diesel fuels in a constant volume combustion chamber

KAUST Repository

Jing, Wei; Roberts, William L.; Fang, Tiegang

2015-01-01

This work investigates the spray combustion of Jet-A fuel in an optical constant-volume combustion chamber under different ambient initial conditions. Ambient temperature was varied at 800 K, 1000 K, and 1200 K and five different ambient O2

Robust Low Cost Liquid Rocket Combustion Chamber by Advanced Vacuum Plasma Process

Science.gov (United States)

Holmes, Richard; Elam, Sandra; Ellis, David L.; McKechnie, Timothy; Hickman, Robert; Rose, M. Franklin (Technical Monitor)

2001-01-01

Next-generation, regeneratively cooled rocket engines will require materials that can withstand high temperatures while retaining high thermal conductivity. Fabrication techniques must be cost efficient so that engine components can be manufactured within the constraints of shrinking budgets. Three technologies have been combined to produce an advanced liquid rocket engine combustion chamber at NASA-Marshall Space Flight Center (MSFC) using relatively low-cost, vacuum-plasma-spray (VPS) techniques. Copper alloy NARloy-Z was replaced with a new high performance Cu-8Cr-4Nb alloy developed by NASA-Glenn Research Center (GRC), which possesses excellent high-temperature strength, creep resistance, and low cycle fatigue behavior combined with exceptional thermal stability. Functional gradient technology, developed building composite cartridges for space furnaces was incorporated to add oxidation resistant and thermal barrier coatings as an integral part of the hot wall of the liner during the VPS process. NiCrAlY, utilized to produce durable protective coating for the space shuttle high pressure fuel turbopump (BPFTP) turbine blades, was used as the functional gradient material coating (FGM). The FGM not only serves as a protection from oxidation or blanching, the main cause of engine failure, but also serves as a thermal barrier because of its lower thermal conductivity, reducing the temperature of the combustion liner 200 F, from 1000 F to 800 F producing longer life. The objective of this program was to develop and demonstrate the technology to fabricate high-performance, robust, inexpensive combustion chambers for advanced propulsion systems (such as Lockheed-Martin's VentureStar and NASA's Reusable Launch Vehicle, RLV) using the low-cost VPS process. VPS formed combustion chamber test articles have been formed with the FGM hot wall built in and hot fire tested, demonstrating for the first time a coating that will remain intact through the hot firing test, and with

Experimental study of improvement on combustion control of fluidized bed combustion chamber; Ryudosho shokyakuro no nenshosei no kaizen ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Izumiya, T.; Baba, K.; Koshida, H.; Uetani, J.; Furuta, M.

1998-10-29

Nippon Steel Corporation has carried out an experimental study using the Yawata waste incinerator plant in order to improve combustion control of a fluidized bed combustion chamber. For controlling the forming of dioxin, combustion control is very important in addition to conventional methods. In this paper, we report two studies about improvements on combustion control. In the first study, we verified improvement on combustion control by modifying gas flow at the freeboard. The operational results of the experiments were studied using the numerical model of the combustion chamber. The modification of gas flow at freeboard was confirmed to be effective to obtain a compact design of fluidized bed combustion chamber for municipal waste. In the second, study we improved combustion control for sewage combustion with municipal waste. In burning municipal waste and sewage, it is especially required to take combustion control into careful consideration. In this experiment, we developed a new device for supplying sewage for the appropriate controlling combustion, and verified its effectiveness to combustion control and an effective reduction of dioxin. (author)

Hot Firing of a Full Scale Copper Tubular Combustion Chamber

National Research Council Canada - National Science Library

Cooley, C

2002-01-01

This paper describes the chamber design and hot firing test results for a full-scale copper tubular combustion chamber that has future application in a high-thrust, upper-stage expander cycle engine...

DIAGNOSIS OF FAILURE OF COMBUSTION IN THE COMBUSTION CHAMBER WITH A THERMOVISION EQUIPMENT

Directory of Open Access Journals (Sweden)

S. V. Vorobiev

2014-01-01

Full Text Available The use of thermovision technology to diagnose failure of the combustion flame test tube of the main combustion chamber gas turbine engine is deal with in the article. Join the thermal radiation of the jet of combustion products and the internal elements was carried out using short-wave thermovision system AGA-782 with spectral spectral filters in several ranges from 3.2 to 5.6 microns. Thermovision is mounted on the axis of the flame tube. The output signal was recorded and processed on a computer in real time, allowing monitor the combustion process and the thermal state of the object during the experiment.

Experimental validation for combustion analysis of GOTHIC code in 2-dimensional combustion chamber

International Nuclear Information System (INIS)

Lee, J. W.; Yang, S. Y.; Park, K. C.; Jung, S. H.

2002-01-01

In this study, the prediction capability of GOTHIC code for hydrogen combustion phenomena was validated with the results of two-dimensional premixed hydrogen combustion experiment executed by Seoul National University. The experimental chamber has about 24 liter free volume (1x0.024x1 m 3 ) and 2-dimensional rectangular shape. The test were preformed with 10% hydrogen/air gas mixture and conducted with combination of two igniter positions (top center, top corner) and two boundary conditions (bottom full open, bottom right half open). Using the lumped parameter and mechanistic combustion model in GOTHIC code, the SNU experiments were simulated under the same conditions. The GOTHIC code prediction of the hydrogen combustion phenomena did not compare well with the experimental results. In case of lumped parameter simulation, the combustion time was predicted appropriately. But any other local information related combustion phenomena could not be obtained. In case of mechanistic combustion analysis, the physical combustion phenomena of gas mixture were not matched experimental ones. In boundary open cases, the GOTHIC predicted very long combustion time and the flame front propagation could not simulate appropriately. Though GOTHIC showed flame propagation phenomenon in adiabatic calculation, the induction time of combustion was still very long compare with experimental results. Also, it was found that the combustion model of GOTHIC code had some weak points in low concentration of hydrogen combustion simulation

Shale oil combustion

International Nuclear Information System (INIS)

Al-dabbas, M.A.

1992-05-01

A 'coutant' carbon steel combustion chamber cooled by water jacket was conslructed to burn diesel fuel and mixlure of shale oil and diesel fuels. During experimental work nir fuel ratio was determined, temperaturces were measured using Chromel/ Almel thermocouple, finally the gasous combustion product analysis was carricd out using gas chromatograph technique. The constructed combustion chamber was operating salisfactory for several hours of continous work. According to the measurements it was found that: the flame temperature of a mixture of diesel and shale oil fuels was greater than the flame temperature of diesel fuel. and the sulfer emissious of a mixture of diesel and shale oil fuels was higher than that of diesel fuel. Calculation indicated that the dry gas energy loss was very high and the incomplete combustion energy loss very small. (author). 23 refs., 35 figs

Shale oil combustion

Energy Technology Data Exchange (ETDEWEB)

Al-dabbas, M A

1992-05-01

A `coutant` carbon steel combustion chamber cooled by water jacket was conslructed to burn diesel fuel and mixlure of shale oil and diesel fuels. During experimental work nir fuel ratio was determined, temperaturces were measured using Chromel/ Almel thermocouple, finally the gasous combustion product analysis was carricd out using gas chromatograph technique. The constructed combustion chamber was operating salisfactory for several hours of continous work. According to the measurements it was found that: the flame temperature of a mixture of diesel and shale oil fuels was greater than the flame temperature of diesel fuel. and the sulfer emissious of a mixture of diesel and shale oil fuels was higher than that of diesel fuel. Calculation indicated that the dry gas energy loss was very high and the incomplete combustion energy loss very small. (author). 23 refs., 35 figs.

Modeling and simulation of combustion chamber and propellant dynamics and issues in active control of combustion instabilities

Science.gov (United States)

Isella, Giorgio Carlo

A method for a comprehensive approach to analysis of the dynamics of an actively controlled combustion chamber, with detailed analysis of the combustion models for the case of a solid rocket propellant, is presented here. The objective is to model the system as interconnected blocks describing the dynamics of the chamber, combustion and control. The analytical framework for the analysis of the dynamics of a combustion chamber is based on spatial averaging, as introduced by Culick. Combustion dynamics are analyzed for the case of a solid propellant. Quasi-steady theory is extended to include the dynamics of the gas-phase and also of a surface layer. The models are constructed so that they produce a combustion response function for the solid propellant that can be immediately introduced in the our analytical framework. The principal objective mechanisms responsible for the large sensitivity, observed experimentally, of propellant response to small variations. We show that velocity coupling, and not pressure coupling, has the potential to be the mechanism responsible for that high sensitivity. We also discuss the effect of particulate modeling on the global dynamics of the chamber and revisit the interpretation of the intrinsic stability limit for burning of solid propellants. Active control is also considered. Particular attention is devoted to the effect of time delay (between sensing and actuation); several methods to compensate for it are discussed, with numerical examples based on the approximate analysis produced by our framework. Experimental results are presented for the case of a Dump Combustor. The combustor exhibits an unstable burning mode, defined through the measurement of the pressure trace and shadowgraph imaging. The transition between stable and unstable modes of operation is characterized by the presence of hysteresis, also observed in other experimental works, and hence not a special characteristic of this combustor. Control is introduced in the

Friction Stir Welding of GR-Cop 84 for Combustion Chamber Liners

Science.gov (United States)

Russell, Carolyn K.; Carter, Robert; Ellis, David L.; Goudy, Richard

2004-01-01

GRCop-84 is a copper-chromium-niobium alloy developed by the Glenn Research Center for liquid rocket engine combustion chamber liners. GRCop-84 exhibits superior properties over conventional copper-base alloys in a liquid hydrogen-oxygen operating environment. The Next Generation Launch Technology program has funded a program to demonstrate scale-up production capabilities of GR-Cop 84 to levels suitable for main combustion chamber production for the prototype rocket engine. This paper describes a novel method of manufacturing the main combustion chamber liner. The process consists of several steps: extrude the GR-Cop 84 powder into billets, roll the billets into plates, bump form the plates into cylinder halves and friction stir weld the halves into a cylinder. The cylinder is then metal spun formed to near net liner dimensions followed by finish machining to the final configuration. This paper describes the friction stir weld process development including tooling and non-destructive inspection techniques, culminating in the successful production of a liner preform completed through spin forming.

RESULTS OF THE DIESEL COMBUSTION CHAMBER OPTIMIZED DESIGN IN THE MULTICRITERIAL TASK ENVIRONMENT

Directory of Open Access Journals (Sweden)

A. Wrublewski

2015-12-01

Full Text Available The results of optimized designing of the higi-speed vehicle diesel engine combustion chamber based on application of the method of parameters space investingation are given. The optimal form of the combustion chamber and the direction of fuel jets at adjusted pressure rate and other functional resrictions are determined according to three criteria of quality – fuel consumption, hard particles and nitric oxide emissions.

Design and Fabrication of Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged Combustion Thrust Chamber Injectors

Science.gov (United States)

Garcia, C. P.; Medina, C. R.; Protz, C. S.; Kenny, R. J.; Kelly, G. W.; Casiano, M. J.; Hulka, J. R.; Richardson, B. R.

2016-01-01

As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. On the current project, several configurations of new main injectors were considered for the thrust chamber assembly of the integrated test article. All the injector elements were of the gas-centered swirl coaxial type, similar to those used on the Russian oxidizer-rich staged-combustion rocket engines. In such elements, oxidizer-rich combustion products from the preburner/turbine exhaust flow through a straight tube, and fuel exiting from the combustion chamber and nozzle regenerative cooling circuits is injected near the exit of the oxidizer tube through tangentially oriented orifices that impart a swirl motion such that the fuel flows along the wall of the oxidizer tube in a thin film. In some elements there is an orifice at the inlet to the oxidizer tube, and in some elements there is a sleeve or "shield" inside the oxidizer tube where the fuel enters. In the current project, several variations of element geometries were created, including element size (i.e., number of elements or pattern density), the distance from the exit of the sleeve to the injector face, the width of the gap between the oxidizer tube inner wall and the outer wall of the sleeve, and excluding the sleeve entirely. This paper discusses the design rationale for each of these element variations, including hydraulic, structural

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.

Development of a self-ignition and combustion model for diesel engines; Modelisation de l`auto-inflammation et de la combustion pour les moteurs diesel

Energy Technology Data Exchange (ETDEWEB)

Pires Da Cruz, A.

1997-12-09

The work concerns self-ignition and combustion modelling in Diesel engines. Special attention is given to turbulence induced effects. Only gas fuel injection is taken into account. Turbulent mixing is identified as one of the main parameters controlling self-ignition in Diesel engines. However, turbulence effects are often neglected by models currently used in engine calculation codes. A new model based on results obtained by direct numerical simulation (DNS) is proposed. It includes turbulence effects by means of the scalar dissipation rate and presumed pdf of the mixture fraction and a chemical reaction progress variable. The model is validated through several steps. First, its results are compared to DNS in simple mixing and self-ignition cases. Then, its averaged version is integrated into the KIVA2-MB calculation code, where its behavior is tested in a one dimensional version and compared to other formulations. Finally, the model is validated with comparisons to experimental results of methane injection into a high pressure combustion chamber filled with hot air. The combustion chamber allows large optical access and therefore, optical diagnostics can be made. (author) 101 refs.

Assesment of PM2.5 emission from corn stover burning determining in chamber combustion

Science.gov (United States)

Hafidawati; Lestari, P.; Sofyan, A.

2018-04-01

Chamber measurement were conducted to determine Particulate Matter (PM2.5) emission from open burning of corn straw at Garut District, West Java. The of this study is to estimate the concentration of PM2.5 for two types of corn (corncobs and cornstover) for five varieties (Bisma, P29, NK, Bisma, NW). Corn residues were collected and then burned in the chamber combustion. The chamber was designed to simulate the burning in the field, which was observed in the field experiment that meteorological condition was calm wind. The samples were collected using a minivol air sampler. The assessment results of PM2.5 concentrations (mg/m3) from open burning experiment in the chamber for five varieties of corn cobs (Bisma, P29, NK, Bisi, NW) was 9.187; 2.843; 7.409; 3.781; 1.895 respectively. Concentration for corn stover burn was 2.060; 5.283; 4.048; 5.306 and 5.697 respectively. Fluctuations in the value of concentration among these varieties reflect variations in combustion conditions (combustion efficiency) and other parameters including water content, biomass conditions and the meteorological conditions. The combustion efficiency (MCE) of the combustion chamber simulation of corncobs ia lower than the MCE of corn stover, that the concentration PM2.5 more emitted from the burning of corn stover. The results of this study presented provide useful information for the development of local emission factors for PM2.5 from open burning of corn stover in Indonesia.

Explosion-induced combustion of hydrocarbon clouds in a chamber

International Nuclear Information System (INIS)

Neuwald, P; Reichenbach, H; Kuhl, A L

2001-01-01

The interaction of the detonation of a solid HE-charge with a non-premixed cloud of hydro-carbon fuel in a chamber was studied in laboratory experiments. Soap bubbles filled with a flammable gas were subjected to the blast wave created by the detonation of PETN-charges (0.2 g < mass < 0.5 g). The dynamics of the combustion system were investigated by means of high-speed photography and measurement of the quasi-static chamber pressure

Premixed combustion under electric field in a constant volume chamber

KAUST Repository

Cha, Min Suk

2012-12-01

The effects of electric fields on outwardly propagating premixed flames in a constant volume chamber were experimentally investigated. An electric plug, subjected to high electrical voltages, was used to generate electric fields inside the chamber. To minimize directional ionic wind effects, alternating current with frequency of 1 kHz was employed. Lean and rich fuel/air mixtures for both methane and propane were tested to investigate various preferential diffusion conditions. As a result, electrically induced instability showing cracked structure on the flame surface could be observed. This cracked structure enhanced flame propagation speed for the initial period of combustion and led to reduction in flame initiation and overall combustion duration times. However, by analyzing pressure data, it was found that overall burning rates are not much affected from the electric field for the pressurized combustion period. The reduction of overall combustion time is less sensitive to equivalence ratio for methane/air mixtures, whereas the results demonstrate pronounced effects on a lean mixture for propane. The improvement of combustion characteristics in lean mixtures will be beneficial to the design of lean burn engines. Two hypothetical mechanisms to explain the electrically induced instability were proposed: 1) ionic wind initiated hydrodynamic instability and 2) thermodiffusive instability through the modification of transport property such as mass diffusivity. © 2012 IEEE.

Premixed combustion under electric field in a constant volume chamber

KAUST Repository

Cha, Min; Lee, Yonggyu

2012-01-01

The effects of electric fields on outwardly propagating premixed flames in a constant volume chamber were experimentally investigated. An electric plug, subjected to high electrical voltages, was used to generate electric fields inside the chamber. To minimize directional ionic wind effects, alternating current with frequency of 1 kHz was employed. Lean and rich fuel/air mixtures for both methane and propane were tested to investigate various preferential diffusion conditions. As a result, electrically induced instability showing cracked structure on the flame surface could be observed. This cracked structure enhanced flame propagation speed for the initial period of combustion and led to reduction in flame initiation and overall combustion duration times. However, by analyzing pressure data, it was found that overall burning rates are not much affected from the electric field for the pressurized combustion period. The reduction of overall combustion time is less sensitive to equivalence ratio for methane/air mixtures, whereas the results demonstrate pronounced effects on a lean mixture for propane. The improvement of combustion characteristics in lean mixtures will be beneficial to the design of lean burn engines. Two hypothetical mechanisms to explain the electrically induced instability were proposed: 1) ionic wind initiated hydrodynamic instability and 2) thermodiffusive instability through the modification of transport property such as mass diffusivity. © 2012 IEEE.

Measurement of O2 in the Combustion Chamber of Apulverized Coal Boiler

Directory of Open Access Journals (Sweden)

Břetislav Janeba

2012-01-01

Full Text Available Operational measurements of the O2 concentration in the combustion chamber of a pulverized coal boiler are not yet common practice. Operators are generally satisfied with measuring the O2 concentration in the second pass of the boiler, usually behind the economizer, where a flue gas sample is extracted for analysis in a classical analyzer. A disadvantage of this approach is that there is a very weak relation between the measured value and the condition in specific locations in the fireplace, e.g. the function of the individual burners and the combustion process as a whole. A new extractionline was developed for measuring the O2 concentration in the combustion chamber. A planar lambda probe is used in this approach. The extraction line is designed to get outputs that can be used directly for diagnosis or management of the combustion in the boiler.

Development and Hotfire Testing of Additively Manufactured Copper Combustion Chambers for Liquid Rocket Engine Applications

Science.gov (United States)

Gradl, Paul R.; Greene, Sandy; Protz, Chris

2017-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM), commonly referred to as additive manufacturing (AM). The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for GRCop-84 (a NASA Glenn Research Center-developed copper, chrome, niobium alloy) commensurate with powder bed AM, evaluate bimetallic deposition, and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. To advance the processes further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic AM chambers. In addition to the LCUSP program, NASA’s Marshall Space Flight Center (MSFC) has completed a series of development programs and hot-fire tests to demonstrate SLM GRCop-84 and other AM techniques. MSFC’s efforts include a 4,000 pounds-force thrust liquid oxygen/methane (LOX/CH4) combustion chamber. Small thrust chambers for 1,200 pounds-force LOX/hydrogen (H2) applications have also been designed and fabricated with SLM GRCop-84. Similar chambers have also completed development with an Inconel 625 jacket bonded to the GRCop-84 material, evaluating direct metal deposition (DMD) laser- and arc-based techniques. The same technologies for these lower thrust applications are being applied to 25,000-35,000 pounds-force main combustion chamber (MCC) designs. This paper describes the design, development, manufacturing and testing of these numerous combustion chambers, and the associated lessons learned throughout their design and development processes.

Investigation on heat transfer enhancement and pressure loss of double swirl chambers cooling

Directory of Open Access Journals (Sweden)

Gang Lin

2013-09-01

Full Text Available By merging two standard swirl chambers, an alternative cooling configuration named double swirl chambers (DSC has been developed. In the DSC cooling configuration, the main physical phenomena of the swirl flow in swirl chamber and the advantages of swirl flow in heat transfer augmentation are maintained. Additionally, three new physical phenomena can be found in DSC cooling configuration, which result in a further improvement of the heat transfer: (1 impingement effect has been observed, (2 internal heat exchange has been enhanced between fluids in two swirls, and (3 “∞” shape swirl has been generated because of cross effect between two chambers, which improves the mixing of the fluids. Because of all these improvements, the DSC cooling configuration leads to a higher globally-averaged thermal performance parameter (Nu¯¯/Nu∞/(f/f01/3 than standard swirl chamber. In particular, at the inlet region, the augmentation of the heat transfer is nearly 7.5 times larger than the fully developed non-swirl turbulent flow and the circumferentially averaged Nusselt number coefficient is 41% larger than the standard swirl chamber. Within the present work, a further investigation on the DSC cooling configuration has been focused on the influence of geometry parameters e.g. merging ratio of chambers and aspect ratio of inlet duct on the cooling performance. The results show a very large influence of these geometry parameters in heat transfer enhancement and pressure drop ratio. Compared with the basic configuration of DSC cooling, the improved configuration with 20% to 23% merging ratio shows the highest globally-averaged thermal performance parameter. With the same cross section area in tangential inlet ducts, the DSC cooling channel with larger aspect ratio shows larger heat transfer enhancement and at the same time reduced pressure drop ratio, which results in a better globally-averaged thermal performance parameter.

Device for combusting spent car tyres made of rubber etc. Anlage zum Verbrennen von nicht mehr erneuerbaren Fahrzeugreifen aus Gummi u. dgl

Energy Technology Data Exchange (ETDEWEB)

Sprunck, H

1980-09-11

The combustion system for rubber tyres etc. consists of a trolley conveyor, an automatic throw-off unit, and an airlock leading to the combustion grate in the furnace. The furnace has a travelling grate which lowers from the airlock to the ash chamber and whose hydraulically moved rods have protruding cooling tongues and drilled holes to supply primary air or cooling air. At the ends of the grate, above the ash box, the combustion chamber is enclosed by a battered brick-and-mortar wall. There are two post-combustion chambers behind the combustion chamber. The ash is transported to the ashbox via spiral conveyors. The high temperature of the flue gases, i.e. 1000 to 1200/sup 0/C, is utilized by a boiler. With its high combustion temperatures (800 to 1400/sup 0/C), the plant assures complete combustion and a metal-containing slag.

Smog chamber study on the evolution of fume from residential coal combustion.

Science.gov (United States)

Geng, Chunmei; Wang, Kun; Wang, Wei; Chen, Jianhua; Liu, Xiaoyu; Liu, Hongjie

2012-01-01

Domestic coal stoves are widely used in countryside and greenbelt residents in China for heating and cooking, and emit considerable pollutants to the atmosphere because of no treatment of their exhaust, which can result in deteriorating local air quality. In this study, a dynamic smog chamber was used to investigate the real-time emissions of gaseous and particulate pollutants during the combustion process and a static smog chamber was used to investigate the fume evolution under simulate light irradiation. The real-time emissions revealed that the total hydrocarbon (THC) and CO increased sharply after ignition, and then quickly decreased, indicating volatilization of hydrocarbons with low molecular weight and incomplete combustion at the beginning stage of combustion made great contribution to these pollutants. There was evident shoulder peak around 10 min combustion for both THC and CO, revealing the emissions from vitrinite combustion. Additionally, another broad emission peak of CO after 30 min was also observed, which was ascribed to the incomplete combustion of the inertinite. Compared with THC and CO, there was only one emission peak for NOx, SO2 and particular matters at the beginning stage of combustion. The fume evolution with static chamber simulation indicated that evident consumption of SO2 and NOx as well as new particle formation were observed. The consumption rates for SO2 and NOx were about 3.44% hr(-1) and 3.68% hr(-1), the new particle formation of nuclei particles grew at a rate of 16.03 nm/hr during the first reaction hour, and the increase of the diameter of accumulation mode particles was evident. The addition of isoprene to the diluted mixture of the fume could promote 03 and secondary particle formation.

Novel application of a combustion chamber for experimental assessment of biomass burning emission

Czech Academy of Sciences Publication Activity Database

Lusini, I.; Pallozi, E.; Corona, P.; Calfapietra, Carlo

2014-01-01

Roč. 94, sep (2014), s. 117-125 ISSN 1352-2310 Institutional support: RVO:67179843 Keywords : forest fires * combustion chamber * combustion gases * volatile organic compounds emission Subject RIV: EH - Ecology, Behaviour Impact factor: 3.281, year: 2014

Development and Hot-fire Testing of Additively Manufactured Copper Combustion Chambers for Liquid Rocket Engine Applications

Science.gov (United States)

Gradl, Paul R.; Greene, Sandy Elam; Protz, Christopher S.; Ellis, David L.; Lerch, Bradley A.; Locci, Ivan E.

2017-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM), commonly referred to as additive manufacturing (AM). The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for GRCop-84 (a NASA Glenn Research Center-developed copper, chrome, niobium alloy) commensurate with powder-bed AM, evaluate bimetallic deposition, and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. To advance the processes further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic AM chambers. In addition to the LCUSP program, NASA has completed a series of development programs and hot-fire tests to demonstrate SLM GRCop-84 and other AM techniques. NASA's efforts include a 4K lbf thrust liquid oxygen/methane (LOX/CH4) combustion chamber and subscale thrust chambers for 1.2K lbf LOX/hydrogen (H2) applications that have been designed and fabricated with SLM GRCop-84. The same technologies for these lower thrust applications are being applied to 25-35K lbf main combustion chamber (MCC) designs. This paper describes the design, development, manufacturing and testing of these numerous combustion chambers, and the associated lessons learned throughout their design and development processes.

Ignition of a Droplet of Composite Liquid Fuel in a Vortex Combustion Chamber

Science.gov (United States)

Valiullin, T. R.; Vershinina, K. Yu; Glushkov, D. O.; Strizhak, P. A.

2017-11-01

Experimental study results of a droplet ignition and combustion were obtained for coal-water slurry containing petrochemicals (CWSP) prepared from coal processing waste, low-grade coal and waste petroleum products. A comparative analysis of process characteristics were carried out in different conditions of fuel droplet interaction with heated air flow: droplet soars in air flow in a vortex combustion chamber, droplet soars in ascending air flow in a cone-shaped combustion chamber, and droplet is placed in a thermocouple junction and motionless in air flow. The size (initial radii) of CWSP droplet was varied in the range of 0.5-1.5 mm. The ignition delay time of fuel was determined by the intensity of the visible glow in the vicinity of the droplet during CWSP combustion. It was established (under similar conditions) that ignition delay time of CWSP droplets in the combustion chamber is lower in 2-3.5 times than similar characteristic in conditions of motionless droplet placed in a thermocouple junction. The average value of ignition delay time of CWSP droplet is 3-12 s in conditions of oxidizer temperature is 600-850 K. Obtained experimental results were explained by the influence of heat and mass transfer processes in the droplet vicinity on ignition characteristics in different conditions of CWSP droplet interaction with heated air flow. Experimental results are of interest for the development of combustion technology of promising fuel for thermal power engineering.

Optical Pressure-Temperature Sensor for a Combustion Chamber

Science.gov (United States)

Wiley, John; Korman, Valentin; Gregory, Don

2008-01-01

A compact sensor for measuring temperature and pressure in a combusti on chamber has been proposed. The proposed sensor would include two optically birefringent, transmissive crystalline wedges: one of sapph ire (Al2O3) and one of magnesium oxide (MgO), the optical properties of both of which vary with temperature and pressure. The wedges wou ld be separated by a vapor-deposited thin-film transducer, which wou ld be primarily temperaturesensitive (in contradistinction to pressur e- sensitive) when attached to a crystalline substrate. The sensor w ould be housed in a rugged probe to survive the extreme temperatures and pressures in a combustion chamber.

Computational fluid dynamics (CFD) analysis of an industrial gas turbine combustion chamber

Energy Technology Data Exchange (ETDEWEB)

Anzai, Thiago Koichi; Fontes, Carlo Eduardo; Ropelato, Karolline [Engineering Simulation and Scientic Software Ltda. (ESSS), Rio de Janeiro, RJ (Brazil)], E-mails: anzai, carlos.fontes, ropelato@esss.com.br; Silva, Luis Fernando Figueira da; Huapaya, Luis Enrique Alva [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. of Mechanical Engineering], E-mail: luisfer.luisalva@esp.puc-rio.br

2010-07-01

The accurate determination of pollutant emission from gas turbine combustors is a crucial problem in situations when such equipment is subject to long periods of operation away from the design point. In such operating conditions, the flow field structure may also drastically differ from the design point one, leading to the presence of undesirable hot spots or combustion instabilities, for instance. A priori experiments on all possible operation conditions is economically unfeasible, therefore, models that allow for the prediction of combustion behavior in the full operation range could be used to instruct power plant operators on the best strategies to be adopted. Since the direct numerical simulation of industrial combustors is beyond reach of the foreseeable computational resources, simplified models should be used for such purpose. This works presents the results of the application to an industrial gas turbine combustion chamber of the CFD technique to the prediction of the reactive flow field. This is the first step on the coupling of reactive CFD results with detailed chemical kinetics modeling using chemical reactor networks, toward the goal of accurately predicting pollutant emissions. The CFD model considers the detailed geometrical information of such a combustion chamber and uses actual operating conditions, calibrated via an overall gas turbine thermodynamical simulation, as boundary conditions. This model retains the basic information on combustion staging, which occurs both in diffusion and lean premixed modes. The turbulence has been modeled using the SST-CC model, which is characterized by a well established regime of accurate predictive capability. Combustion and turbulence interaction is accounted for by using the Zimont et al. model, which makes use of on empirical expression for the turbulent combustion velocity for the closure of the progress variable transport equation. A high resolution scheme is used to solve the advection terms of the

Ceramic Matrix Composite Combustion Chamber for HAN-Based Monopropellants, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Ultramet will design and fabricate a lightweight, high temperature 5-lbf combustion chamber. The system will be designed for use with the AF-315 family of...

Lightweight Ultrahigh Temperature CMC-Lined C/C Combustion Chambers, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — NASA and DoD are seeking high-performance, lightweight liquid rocket combustion chambers with future performance goals that cannot be achieved using state-of-the-art...

Closed loop steam cooled airfoil

Science.gov (United States)

Widrig, Scott M.; Rudolph, Ronald J.; Wagner, Gregg P.

2006-04-18

An airfoil, a method of manufacturing an airfoil, and a system for cooling an airfoil is provided. The cooling system can be used with an airfoil located in the first stages of a combustion turbine within a combined cycle power generation plant and involves flowing closed loop steam through a pin array set within an airfoil. The airfoil can comprise a cavity having a cooling chamber bounded by an interior wall and an exterior wall so that steam can enter the cavity, pass through the pin array, and then return to the cavity to thereby cool the airfoil. The method of manufacturing an airfoil can include a type of lost wax investment casting process in which a pin array is cast into an airfoil to form a cooling chamber.

Optimization of combustion chamber geometry for natural gas engines with diesel micro-pilot-induced ignition

International Nuclear Information System (INIS)

Wang, Bin; Li, Tie; Ge, Linlin; Ogawa, Hideyuki

2016-01-01

Highlights: • Combustion chamber geometry is optimized to reduce the HC/CO emissions. • CFD model is calibrated against the spray visualization and engine bench test data. • Design space is explored by the multi-objective NSGA-II with Kriging meta-model. • HC and CO emissions are respectively reduced by 56.47% and 33.55%. - Abstract: Smokeless, low nitrogen oxides (NOx), and high thermal efficiency have been achieved through the lean-burn concept for natural gas engine with diesel micro-pilot-induced ignition (MPII). However, the combustion chamber is usually not specialized for natural gas combustion, and increases in the unburned hydrocarbon (HC) and carbon monoxide (CO) emissions are still a challenge for this type of engines. This paper describes optimization of the combustion chamber geometry to reduce the HC and CO emissions and improve the combustion efficiency in the MPII natural gas engine. The 3-D computational fluid dynamics (CFD) simulation model coupled with a chemical reaction mechanism is described. The temporal development of the short-pulsed diesel spray in a high pressure constant-volume vessel is measured and used to calibrate the spray model in the CFD simulation. The simulation models are validated by the experimental data of the in-cylinder pressure trace, apparent heat release rate (AHRR) and exhaust gas emissions from a single-cylinder MPII natural gas engine. To generate the various combustion chamber geometries, the bowl outline is parameterized by the two cubic Bezier curves while keeping the compression ratio constant. The available design space is explored by the multi-objective non-dominated sorting genetic algorithm II (NSGA-II) with Kriging-based meta-model. With the optimization, the HC and CO emissions are reduced by 56.47% and 33.55%, respectively, while the NOx emissions, the maximum rate of pressure rise and the gross indicated thermal efficiency that are employed as the constraints are slightly improved. Finally, the

LOX/Methane Regeneratively-Cooled Rocket Engine Development

Data.gov (United States)

National Aeronautics and Space Administration — The purpose of this project is to advance the technologies required to build a subcritical regeneratively cooled liquid oxygen/methane rocket combustion chamber for...

AUTOMATIC CONTROL SYSTEM FOR REGULATED HIGH TEMPERATURE MAIN COMBUSTION CHAMBER OF MANEUVERABLE AIRCRAFT MULTIMODE GAS TURBINE ENGINE

Directory of Open Access Journals (Sweden)

T. V. Gras’Ko

2014-01-01

Full Text Available The paper describes choosing and substantiating the control laws, forming the appearance the automatic control system for regulated high temperature main combustion chamber of maneuverable aircraft multimode gas turbine engine aimed at sustainable and effective functioning of main combustion chamber within a broad operation range.

Soot temperature and KL factor for biodiesel and diesel spray combustion in a constant volume combustion chamber

KAUST Repository

Zhang, Ji; Jing, Wei; Roberts, William L.; Fang, Tiegang

2013-01-01

This paper presents measurements of the soot temperature and KL factor for biodiesel and diesel combustion in a constant volume chamber using a two-color technique. This technique uses a high-speed camera coupled with two narrowband filters (550. nm

Numerical analysis of the thermo-fluid-dynamic field in the combustion chamber of an incinerator plant

International Nuclear Information System (INIS)

Costa, M.; Dell'Isola, M.; Massarotti, N.

2009-01-01

As the interest for energy recovery from waste incineration has increased over the years, concern for the impact such processes have on the environment has also grown. To reduce such an impact, the legislation enforced in Italy and Europe imposes important restrictions on the temperature of the exhausts in the combustion chamber, which must be kept above certain values depending on the type of waste that is being incinerated, for a given period of time. Such conditions can be rather difficult and certainly very expensive to monitor with acceptable accuracy. In this work, a numerical approach is presented for modelling waste combustion in a full scale incineration plant. Both solid and gas phase reactions are considered. Various modes of heat and mass transfer between the waste bed, the air and the combustion products are taken into account, as well as radiation from the combustion chamber walls and the combustion products. The temperature distribution in the combustion chamber is obtained considering either forced or mixed convection. It is therefore shown that neglecting buoyancy effects may lead to appreciable errors. Verification of the code performance is based on comparison with the results of an experimental campaign at a full scale plant in Italy.

Combustion chamber for solid and liquid waste

Energy Technology Data Exchange (ETDEWEB)

Vcelak, L.; Kocica, J.; Trnobransky, K.; Hrubes, J. (VSCHT, Prague (Czechoslovakia))

1989-04-01

Describes combustion chamber incorporated in a new boiler manufactured by Elitex of Kdyne to burn waste products and occasionally liquid and solid waste from neighboring industries. It can handle all kinds of solids (paper, plastics, textiles, rubber, household waste) and liquids (volatile and non-volatile, zinc, chromium, etc.) and uses coal as a fuel additive. Its heat output is 3 MW, it can burn 1220 kg/h of coal (without waste, calorific value 11.76 MJ/kg) or 500 kg/h of coal (as fuel additive, calorific value 11.76 MJ/kg) or 285 kg/h of solid waste (calorific value 20.8 MJ/kg). Efficiency is 75%, capacity is 103 m{sup 3} and flame temperature is 1,310 C. Individual components are designed for manufacture in small engineering workshops with basic equipment. A disk absorber with alkaline filling is fitted for removal of harmful substances arising when PVC or tires are combusted.

Design, Fabrication and Test of a Full Scale Copper Tubular Combustion Chamber

National Research Council Canada - National Science Library

Cooley, Christine

2002-01-01

This paper presents the design fabrication and test of a full scale copper tubular combustion chamber as an enabling technology for future application in a high thrust upper-stage expander-cycle engine...

Emission characteristics of premixed lean diesel combustion. Effects of injection nozzle and combustion chamber shape on combustion and emission characteristics; Kihaku yokongo diesel nensho no haishutsubutsu tokusei. Funmu keijo oyobi nenshoshitsu keijo ga haishutsu gas tokusei ni oyobosu eikyo

Energy Technology Data Exchange (ETDEWEB)

Harada, A; Sasaki, S; Miyamoto, T; Akagawa, H; Tsujimura, K

1997-10-01

Many articles about low NOx emission combustion are reported. A mixture formation is necessary to success low NOx emission combustion. But, there is few reports about the effect of nozzle and combustion shape on emissions which give influence on mixture. In this paper, the effects on characteristic of combustion and emissions of some land of injection nozzle and combustion chamber shape were investigated. As a result, it was cleared that the influence of combustion chamber shape on characteristic of combustion and emissions was varied by spray shape, and pintle type injection nozzle was suitable for PREDIC. 7 refs., 10 figs., 1 tab.

Influence of the Structure of a Solid-Fuel Mixture on the Thermal Efficiency of the Combustion Chamber of an Engine System

Science.gov (United States)

Futko, S. I.; Koznacheev, I. A.; Ermolaeva, E. M.

2014-11-01

On the basis of thermodynamic calculations, the features of the combustion of a solid-fuel mixture based on the glycidyl azide polymer were investigated, the thermal cycle of the combustion chamber of a model engine system was analyzed, and the efficiency of this chamber was determined for a wide range of pressures in it and different ratios between the components of the combustible mixture. It was established that, when the pressure in the combustion chamber of an engine system increases, two maxima arise successively on the dependence of the thermal efficiency of the chamber on the weight fractions of the components of the combustible mixture and that the first maximum shifts to the side of smaller concentrations of the glycidyl azide polymer with increase in the pressure in the chamber; the position of the second maximum is independent of this pressure, coincides with the minimum on the dependence of the rate of combustion of the mixture, and corresponds to the point of its structural phase transition at which the mole fractions of the carbon and oxygen atoms in the mixture are equal. The results obtained were interpreted on the basis of the Le-Chatelier principle.

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.

Low temperature combustion of organic coal-water fuel droplets containing petrochemicals while soaring in a combustion chamber model

Directory of Open Access Journals (Sweden)

Valiullin Timur R.

2017-01-01

Full Text Available The paper examines the integral characteristics (minimum temperature, ignition delay times of stable combustion initiation of organic coal-water fuel droplets (initial radius is 0.3-1.5 mm in the oxidizer flow (the temperature and velocity varied in ranges 500-900 K, 0.5-3 m/s. The main components of organic coal-water fuel were: brown coal particles, filter-cakes obtained in coal processing, waste engine, and turbine oils. The different modes of soaring and ignition of organic coal-water fuel have been established. The conditions have been set under which it is possible to implement the sustainable soaring and ignition of organic coal-water fuel droplets. We have compared the ignition characteristics with those defined in the traditional approach (based on placing the droplets on a low-inertia thermocouple junction into the combustion chamber. The paper shows the scale of the influence of heat sink over the thermocouple junction on ignition inertia. An original technique for releasing organic coal-water fuel droplets to the combustion chamber was proposed and tested. The limitations of this technique and the prospects of experimental results for the optimization of energy equipment operation were also formulated.

Design, Development and Hotfire Testing of Monolithic Copper and Bimetallic Additively Manufactured Combustion Chambers

Science.gov (United States)

Gradl, Paul; Barnett, Greg; Brandsmeier, Will; Greene, Sandy Elam; Protz, Chris

2016-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM) otherwise commonly referred to as additive manufacturing. The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for the GRCop-84 copper-alloy commensurate with powder bed additive manufacturing, evaluate bimetallic deposition and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. As a direct spin off of this program, NASA is working with industry partners to further develop the printing process for the GRCop-84 material in addition to the C-18150 (CuCrZr) material. To advance the process further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic additively manufactured chambers. A 1.2k sized thrust-chamber was designed and developed to compare the printing process of the GRCop-84 and C-18150 SLM materials. A series of similar MCC liners also completed development with an Inconel 625 jacket bonded to the GRcop-84 liner evaluating direct metal deposition (DMD) laser and arc-based techniques. This paper describes the design, development, manufacturing and testing of these combustion chambers and associated lessons learned throughout the design and development process.

Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber

KAUST Repository

Shi, Xian

2017-01-05

Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber are numerically investigated using an 1-D unsteady, shock-capturing, compressible and reacting flow solver. Different combinations of reaction front propagation and end-gas combustion modes are observed, i.e., 1) deflagration without end-gas combustion, 2) deflagration to end-gas autoignition, 3) deflagration to end-gas detonation, 4) developing or developed detonation, occurring in the sequence of increasing initial temperatures. Effects of ignition location and chamber size are evaluated: the asymmetric ignition is found to promote the reactivity of unburnt mixture compared to ignitions at center/wall, due to additional heating from asymmetric pressure waves. End-gas combustion occurs earlier in smaller chambers, where end-gas temperature rise due to compression heating from the deflagration is faster. According to the ξ−ε regime diagram based on Zeldovich theory, modes of reaction front propagation are primarily determined by reactivity gradients introduced by initial ignition, while modes of end-gas combustion are influenced by the total amount of unburnt mixture at the time when autoignition occurs. A transient reactivity gradient method is provided and able to capture the occurrence of detonation.

Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber

KAUST Repository

Shi, Xian; Ryu, Je Ir; Chen, Jyh-Yuan; Dibble, Robert W.

2017-01-01

Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber are numerically investigated using an 1-D unsteady, shock-capturing, compressible and reacting flow solver. Different combinations of reaction front propagation and end-gas combustion modes are observed, i.e., 1) deflagration without end-gas combustion, 2) deflagration to end-gas autoignition, 3) deflagration to end-gas detonation, 4) developing or developed detonation, occurring in the sequence of increasing initial temperatures. Effects of ignition location and chamber size are evaluated: the asymmetric ignition is found to promote the reactivity of unburnt mixture compared to ignitions at center/wall, due to additional heating from asymmetric pressure waves. End-gas combustion occurs earlier in smaller chambers, where end-gas temperature rise due to compression heating from the deflagration is faster. According to the ξ−ε regime diagram based on Zeldovich theory, modes of reaction front propagation are primarily determined by reactivity gradients introduced by initial ignition, while modes of end-gas combustion are influenced by the total amount of unburnt mixture at the time when autoignition occurs. A transient reactivity gradient method is provided and able to capture the occurrence of detonation.

Device for automatically operating cooling mode of water in a pressure suppression chamber

International Nuclear Information System (INIS)

Sato, Hideyuki.

1975-01-01

Object: To provide a system for removing residual heat in a reactor safety system, which can automatically cool water in a pressure suppression chamber when a load on a generator is cut off, so as not to scram the reactor. Structure: When a load cut-off signal is generated by means of rapid closure of a turbine regulating valve or due to the load unbalance relay of generator output, or the like, a sea water pump is started to fully open an outlet valve for the sea water pump, a heat exchanging inlet valve and a minimum crow valve and to fully close a heat exchanging bypass valve. In this manner, cooling water for the heat exchanger is secured to start the pump in the system for removing residual heat, and when the pump discharge pressure is in normal condition, the inlet valve in pressure suppression chamber and the spray valve in the pressure suppression chamber are fully opened to automatically cool water in the pressure suppression chamber. (Hanada, M.)

High resolution real time capable combustion chamber simulation; Zeitlich hochaufloesende echtzeitfaehige Brennraumsimulation

Energy Technology Data Exchange (ETDEWEB)

Piewek, J. [Volkswagen AG, Wolfsburg (Germany)

2008-07-01

The article describes a zero-dimensional model for the real time capable combustion chamber pressure calculation with analogue pressure sensor output. The closed-loop-operation of an Engine Control Unit is shown at the hardware-in-the-loop-simulator (HiL simulator) for a 4-cylinder common rail diesel engine. The presentation of the model focuses on the simulation of the load variation which does not depend on the injection system and thus the simulated heat release rate. Particular attention is paid to the simulation and the resulting test possibilities regarding to full-variable valve gears. It is shown that black box models consisting in the HiL mean value model for the aspirated gas mass, the exhaust gas temperature after the outlet valve and the mean indicated pressure can be replaced by calculations from the high-resolution combustion chamber model. (orig.)

A numerical investigation of the entropy generation in and thermodynamic optimization of a combustion chamber

International Nuclear Information System (INIS)

Arjmandi, H.R.; Amani, E.

2015-01-01

In this study, we are simulating the turbulent combustion of a mixed bluff-body swirl stabilized flame in a gas turbine combustion chamber and investigating the effects of different parameters, including the swirl number, distance between the air and fuel nozzle which is called bluff size, equivalence ratio, inlet fuel flow rate, and the inlet air velocity, on the entropy generation. We perform the process of the design of the combustion chamber by proposing the optimal value of each parameter based on the EGM (entropy generation minimization) method under the two maximum allowable temperature and size constraints. Two common methods of entropy generation calculation, one based on the overall entropy balance on a system and the other based on the local entropy generation rate calculation, are used and compared in this study. Our results show that the deviation between the total entropy generations calculated by the two methods is 6.4% in average which is an acceptable error in turbulent combustion simulations. Also, the two opposing factors, namely chemical reaction and heat transfer, have the main contribution to the total entropy generation. - Highlights: • We perform the design of a combustion chamber using CFD and based on the EGM method. • We use and compare two methods for computing the total entropy generation. • We also study the entropy generation due to different phenomena separately. • Reaction and heat transfer have the dominant contribution to the entropy generation

Hybrid energy converter based on swirling combustion chambers: the hydrocarbon feeding analysis

Directory of Open Access Journals (Sweden)

Angelo Minotti

2017-05-01

Full Text Available This manuscript reports the latest investigations about a miniaturized hybrid energy power source, compatible with thermal/electrical conversion, by a thermo-photovoltaic cell, and potentially useful for civil and space applications. The converter is a thermally-conductive emitting parallelepiped element and the basic idea is to heat up its emitting surfaces by means of combustion, occurred in swirling chambers, integrated inside the device, and/or by the sun, which may work simultaneously or alternatively to the combustion. The current upgrades consist in examining whether the device might fulfill specific design constraints, adopting hydrocarbons-feeding. Previous papers, published by the author, demonstrate the hydrogen-feeding effectiveness. The project’s constraints are: 1 emitting surface dimensions fixed to 30 × 30 mm, 2 surface peak temperature T > 1000 K and the relative ∆T < 100 K (during the combustion mode, 3 the highest possible delivered power to the ambient, and 4 thermal efficiency greater than 20% when works with solar energy. To this end, a 5 connected swirling chambers configuration (3 mm of diameter, with 500 W of injected chemical power, stoichiometric conditions and detailed chemistry, has been adopted. Reactive numerical simulations show that the stiff methane chemical structure obliges to increase the operating pressure, up to 10 atm, and to add hydrogen, to the methane fuel injection, in order to obtain stable combustion and efficient energy conversion.

High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner For Advanced Rocket Engines

Science.gov (United States)

Bhat, Biliyar N.; Ellis, David; Singh, Jogender

2014-01-01

Advanced high thermal conductivity materials research conducted at NASA Marshall Space Flight Center (MSFC) with state of the art combustion chamber liner material NARloy-Z showed that its thermal conductivity can be increased significantly by adding diamond particles and sintering it at high temperatures. For instance, NARloy-Z containing 40 vol. percent diamond particles, sintered at 975C to full density by using the Field assisted Sintering Technology (FAST) showed 69 percent higher thermal conductivity than baseline NARloy-Z. Furthermore, NARloy-Z-40vol. percent D is 30 percent lighter than NARloy-Z and hence the density normalized thermal conductivity is 140 percent better. These attributes will improve the performance and life of the advanced rocket engines significantly. By one estimate, increased thermal conductivity will directly translate into increased turbopump power up to 2X and increased chamber pressure for improved thrust and ISP, resulting in an expected 20 percent improvement in engine performance. Follow on research is now being conducted to demonstrate the benefits of this high thermal conductivity NARloy-Z-D composite for combustion chamber liner applications in advanced rocket engines. The work consists of a) Optimizing the chemistry and heat treatment for NARloy-Z-D composite, b) Developing design properties (thermal and mechanical) for the optimized NARloy-Z-D, c) Fabrication of net shape subscale combustion chamber liner, and d) Hot fire testing of the liner for performance. FAST is used for consolidating and sintering NARlo-Z-D. The subscale cylindrical liner with built in channels for coolant flow is also fabricated near net shape using the FAST process. The liner will be assembled into a test rig and hot fire tested in the MSFC test facility to determine performance. This paper describes the development of this novel high thermal conductivity NARloy-Z-D composite material, and the advanced net shape technology to fabricate the combustion

Effect of Chamber Pressurization Rate on Combustion and Propagation of Solid Propellant Cracks

Science.gov (United States)

Yuan, Wei-Lan; Wei, Shen; Yuan, Shu-Shen

2002-01-01

area of the propellant grain satisfies the designed value. But cracks in propellant grain can be generated during manufacture, storage, handing and so on. The cracks can provide additional surface area for combustion. The additional combustion may significantly deviate the performance of the rocket motor from the designed conditions, even lead to explosive catastrophe. Therefore a thorough study on the combustion, propagation and fracture of solid propellant cracks must be conducted. This paper takes an isolated propellant crack as the object and studies the effect of chamber pressurization rate on the combustion, propagation and fracture of the crack by experiment and theoretical calculation. deformable, the burning inside a solid propellant crack is a coupling of solid mechanics and combustion dynamics. In this paper, a theoretical model describing the combustion, propagation and fracture of the crack was formulated and solved numerically. The interaction of structural deformation and combustion process was included in the theoretical model. The conservation equations for compressible fluid flow, the equation of state for perfect gas, the heat conducting equation for the solid-phase, constitutive equation for propellant, J-integral fracture criterion and so on are used in the model. The convective burning inside the crack and the propagation and fracture of the crack were numerically studied by solving the set of nonlinear, inhomogeneous gas-phase governing equations and solid-phase equations. On the other hand, the combustion experiments for propellant specimens with a precut crack were conducted by RTR system. Predicted results are in good agreement with experimental data, which validates the reasonableness of the theoretical model. Both theoretical and experimental results indicate that the chamber pressurization rate has strong effects on the convective burning in the crack, crack fracture initiation and fracture pattern.

Numerical analysis on the effect of swirl ratios on swirl chamber combustion system of DI diesel engines

International Nuclear Information System (INIS)

Wei, Shengli; Wang, Feihu; Leng, Xianyin; Liu, Xin; Ji, Kunpeng

2013-01-01

Highlights: • A new swirl chamber combustion system of DI diesel engines is proposed. • The appropriate vortex motion can reduce the wall concentration of mixture. • It has best emissions at swirl ratio of 0.8. • Before spray, the turbulent kinetic energy is primarily controlled by the squish. • After spray, the combustion swirl and reverse squish have a great impact on TKE. - Abstract: In order to improve the spray spatial distribution and promote the mixture quality, enhancing airflow movement in a combustion chamber, a new swirl chamber combustion system in direct injection (DI) diesel engines is proposed. The mixture formation and combustion progress in the cylinder are simulated and investigated at several different swirl ratios by using the AVL-FIRE code. The results show that in view of the fuel/air equivalence ratio distribution, the uniformity of mixture with swirl ratio of 0.2 is better. Before spray injection, the turbulent kinetic energy distribution is primarily controlled by the squish. After spray, the combustion swirl and reverse squish swirl have an effect on temperature distribution and turbulent kinetic energy (TKE) in the cylinder. The NO mass fraction is the lowest at swirl ratio of 0.8 and the highest at swirl ratio of 2.7, while Soot mass fraction is the lowest at swirl ratio of 0.2 and the highest at swirl ratio of 3.2. The appropriate swirl is benefit to improve combustion. To sum up, the emissions at swirl ratio of 0.8 has a better performance in the new combustion system

Rapid Manufacture of Combustion Chambers Using Ductile, High Strength MMCs (1000-803), Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Triton Systems, Inc. (Triton) proposes to develop a cost-effective manufacturing approach to fabricate combustion chambers for a rocket technology demonstrator...

Modeling of atomization and distribution of drop-liquid fuel in unsteady swirling flows in a combustion chamber and free space

Science.gov (United States)

Sviridenkov, A. A.; Toktaliev, P. D.; Tretyakov, V. V.

2018-03-01

Numerical and experimental research of atomization and propagation of drop-liquid phase in swirling flow behind the frontal device of combustion chamber was performed. Numerical procedure was based on steady and unsteady Reynolds equations solution. It's shown that better agreement with experimental data could be obtained with unsteady approach. Fractional time step method was implemented to solve Reynolds equations. Models of primary and secondary breakup of liquid fuel jet in swirling flows are formulated and tested. Typical mean sizes of fuel droplets for base operational regime of swirling device and combustion chamber were calculated. Comparison of main features of internal swirling flow in combustion chamber with unbounded swirling flow was made.

Boiler using combustible fluid

Science.gov (United States)

Baumgartner, H.; Meier, J.G.

1974-07-03

A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.

Laser-assisted homogeneous charge ignition in a constant volume combustion chamber

Science.gov (United States)

Srivastava, Dhananjay Kumar; Weinrotter, Martin; Kofler, Henrich; Agarwal, Avinash Kumar; Wintner, Ernst

2009-06-01

Homogeneous charge compression ignition (HCCI) is a very promising future combustion concept for internal combustion engines. There are several technical difficulties associated with this concept, and precisely controlling the start of auto-ignition is the most prominent of them. In this paper, a novel concept to control the start of auto-ignition is presented. The concept is based on the fact that most HCCI engines are operated with high exhaust gas recirculation (EGR) rates in order to slow-down the fast combustion processes. Recirculated exhaust gas contains combustion products including moisture, which has a relative peak of the absorption coefficient around 3 μm. These water molecules absorb the incident erbium laser radiations ( λ=2.79 μm) and get heated up to expedite ignition. In the present experimental work, auto-ignition conditions are locally attained in an experimental constant volume combustion chamber under simulated EGR conditions. Taking advantage of this feature, the time when the mixture is thought to "auto-ignite" could be adjusted/controlled by the laser pulse width optimisation, followed by its resonant absorption by water molecules present in recirculated exhaust gas.

Modelling of EAF off-gas post combustion in dedusting systems using CFD methods

Energy Technology Data Exchange (ETDEWEB)

Tang, X.; Kirschen, M.; Pfeifer, H. [Inst. for Industrial Furnaces and Heat Engineering in Metallurgy, RWTH Aachen, Aachen (Germany); Abel, M. [VAI-Fuchs GmbH, Willstaett (Germany)

2003-04-01

To comply with the increasingly strict environmental regulations, the poisonous off-gas species, e.g. carbon monoxide (CO), produced in the electric arc furnace (EAF) must be treated in the dedusting system. In this work, gas flow patterns of the off-gas post combustion in three different dedusting system units were simulated with a computational fluid dynamics (CFD) code: (1) post combustion in a horizontal off-gas duct, (2) post combustion in a water cooled post combustion chamber without additional energy supply (no gas or air/oxygen injectors) and (3) post combustion in a post combustion chamber with additional energy input (gas, air injectors and ignition burner, case study of VAI-Fuchs GmbH). All computational results are illustrated with gas velocity, temperature distribution and chemical species concentration fields for the above three cases. In case 1, the effect of different false air volume flow rates at the gap between EAF elbow and exhaust gas duct on the external post combustion of the off-gas was investigated. For case 2, the computed temperature and chemical composition (CO, CO{sub 2} and O{sub 2}) of the off-gas at the post chamber exit are in good agreement with additional measurements. Various operating conditions for case 3 have been studied, including different EAF off-gas temperatures and compositions, i. e. CO content, in order to optimize oxygen and burner gas flow rates. Residence time distributions in the external post combustion chambers have been calculated for cases 2 and 3. Derived temperature fields of the water cooled walls yield valuable information on thermally stressed parts of post combustion units. The results obtained in this work may also gain insight to future investigation of combustion of volatile organic components (VOC) or formation of nitrogen oxide (NO{sub x}) and permit the optimization of the operation and design of the off-gas dedusting system units. (orig.)

Low-Cost and Light-Weight Transpiration-Cooled Thrust Chambers, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The proposed effort aims to evaluate the feasibility of using transpiration-cooled Titanium as the primary material in small-scale thrust chambers for in-space...

Design and testing of a heat pipe gas combustion system for the STM4-120 Stirling engine

Science.gov (United States)

Khalili, K.; Godett, T. M.; Meijer, R. J.; Verhey, R. P.

Evaporators of a novel geometry, designed to have a more compact size yet the same output as larger, conventional heat pipes, have been fabricated and tested. A technique was developed to calculate capillary pressure required inside the heat pipe. Several quarter- and full-scale evaporators were designed and successfully tested. The burner, film-cooled combustion chamber, and preheater were designed and tested separately. A complete heat pipe gas combustion system (HPGC) was tested, showing an efficiency of 89 percent was measured at 20 kWth. A film-cooled combustion chamber was tested with flame temperatures of 2200 C and wall temperatures below 1000 C using preheated air for film cooling. Also, a full-scale HPGC was tested at an excess of 95 kWth, showing efficiency in the range of 85 to 90 percent under steady-state conditions. Results of transient and startup tests, carried out to evaluate the performance of the heat pipe, all also reported.

Hot gas path component cooling system having a particle collection chamber

Science.gov (United States)

Miranda, Carlos Miguel; Lacy, Benjamin Paul

2018-02-20

A cooling system for a hot gas path component includes a substrate having an outer surface and an inner surface. The inner surface defines at least one interior space. A passage is formed in the substrate between the outer surface and the inner surface. An access passage is formed in the substrate and extends from the outer surface to the inner space. The access passage is formed at a first acute angle to the passage and includes a particle collection chamber. The access passage is configured to channel a cooling fluid to the passage. Furthermore, the passage is configured to channel the cooling fluid therethrough to cool the substrate.

Influence of the kind of fuel oil on the deposit composition in the diesel engine combustion chamber

Energy Technology Data Exchange (ETDEWEB)

Tarkowski, P.; Sarzynski, J.; Budzynski, P.; Paluch, R.; Wiertel, M. [Technical University of Lublin, Lublin (Poland)

2001-08-10

The authors studied deposits from combustion chambers of high-pressure engines supplied with standard fuel (SO) and ecological fuel of City-Diesel type. Chemical analysis, X-ray diffractograms, Moessbauer absorption and additionally Raman wavenumber measurements were made. The wearing of some engine elements was examined by the profilometric method. By using ecological fuel, the deposits were shown to contain four to give times less iron compounds than standard fuel supply. This accounts for a smaller attrition of the combustion chamber elements, and thus longer durability of the engine. 7 refs., 4 figs., 5 tabs.

Heat release determination in a constant volume combustion chamber from the instantaneous cylinder pressure

International Nuclear Information System (INIS)

Lapuerta, Magín; Sanz-Argent, Josep; Raine, Robert

2014-01-01

A diagnostic method has been developed to interpret the results of basic combustion studies with diesel-like fuels performed in a constant volume reactor originally conceived for cetane number measurements. The main target of the method is to calculate the instantaneous heat release over time from the chamber pressure experimental signal. The method incorporates filtering of the raw data to eliminate the oscillations recorded as a consequence of the location of the pressure sensor. It considers homogeneity of the gaseous mixture (single zone model) and change in its composition due to the combustion process. A semi-empirical heat transfer model was also proposed and its coefficients were fitted from experimental results obtained in the constant volume chamber using diesel fuel. -- Highlights: • A diagnostic model for constant volume reactors has been developed and tested. • Updating the gas composition after combustion improves accuracy of the method. • Heat transfer coefficients are used for the fulfillment of boundary conditions. • The model provides a deeper insight than the apparent heat release analysis

Thermoelectric self-cooling for power electronics: Increasing the cooling power

International Nuclear Information System (INIS)

Martinez, Alvaro; Astrain, David; Aranguren, Patricia

2016-01-01

Thermoelectric self-cooling was firstly conceived to increase, without electricity consumption, the cooling power of passive cooling systems. This paper studies the combination of heat pipe exchangers and thermoelectric self-cooling, and demonstrates its applicability to the cooling of power electronics. Experimental tests indicate that source-to-ambient thermal resistance reduces by around 30% when thermoelectric self-cooling system is installed, compared to that of the heat pipe exchanger under natural convection. Neither additional electric power nor cooling fluids are required. This thermal resistance reaches 0.346 K/W for a heat flux of 24.1 kW/m"2, being one order of magnitude lower than that obtained in previous designs. In addition, the system adapts to the cooling demand, reducing this thermal resistance for increasing heat. Simulation tests have indicated that simple system modifications allow relevant improvements in the cooling power. Replacement of a thermoelectric module with a thermal bridge leads to 33.54 kW/m"2 of top cooling power. Likewise, thermoelectric modules with shorter legs and higher number of pairs lead to a top cooling power of 44.17 kW/m"2. These results demonstrate the applicability of thermoelectric self-cooling to power electronics. - Highlights: • Cooling power of passive systems increased. • No electric power consumption. • Applicable for the cooling of power electronics. • Up to 44.17 kW/m"2 of cooling power, one order of magnitude higher. • Source-to-ambient thermal resistance reduces by 30%.

Combustion Chamber Fluid Dynamics and Hypergolic Gel Propellant Chemistry Simulations for Selectable Thrust Rocket Engines

National Research Council Canada - National Science Library

Nusca, Michael J; Chen, Chiung-Chu; McQuaid, Michael J

2007-01-01

.... Computational fluid dynamics is employed to model the chemically reacting flow within a system's combustion chamber, and computational chemistry is employed to characterize propellant physical and reactive properties...

Specifics of phytomass combustion in small experimental device

Science.gov (United States)

Lenhard, Richard; Mičieta, Jozef; Jandačka, Jozef; Gavlas, Stanislav

2015-05-01

A wood pellet combustion carries out with high efficiency and comfort in modern pellet boilers. These facts help to increase the amount of installed pellet boilers in households. The combustion process quality depends besides the combustion conditions also on the fuel quality. The wood pellets, which don`t contain the bark and branches represent the highest quality. Because of growing pellet demand, an herbal biomass (phytomass), which is usually an agricultural by-product becomes economically attractive for pellet production. Although the phytomass has the net calorific value relatively slightly lower than the wood biomass, it is often significantly worse in view of the combustion process and an emission production. The combustion of phytomass pellets causes various difficulties in small heat sources, mainly due to a sintering of fuel residues. We want to avoid the ash sintering by a lowering of temperature in the combustion chamber below the ash sintering temperature of phytomass via the modification of a burner design. For research of the phytomass combustion process in the small boilers is constructed the experimental combustion device. There will investigate the impact of cooling intensity of the combustion chamber on the combustion process and emissions. Arising specific requirements from the measurement will be the basis for the design of the pellet burner and for the setting of operating parameters to the trouble-free phytomass combustion was guaranteed.

Specifics of phytomass combustion in small experimental device

Directory of Open Access Journals (Sweden)

Lenhard Richard

2015-01-01

Full Text Available A wood pellet combustion carries out with high efficiency and comfort in modern pellet boilers. These facts help to increase the amount of installed pellet boilers in households. The combustion process quality depends besides the combustion conditions also on the fuel quality. The wood pellets, which don`t contain the bark and branches represent the highest quality. Because of growing pellet demand, an herbal biomass (phytomass, which is usually an agricultural by-product becomes economically attractive for pellet production. Although the phytomass has the net calorific value relatively slightly lower than the wood biomass, it is often significantly worse in view of the combustion process and an emission production. The combustion of phytomass pellets causes various difficulties in small heat sources, mainly due to a sintering of fuel residues. We want to avoid the ash sintering by a lowering of temperature in the combustion chamber below the ash sintering temperature of phytomass via the modification of a burner design. For research of the phytomass combustion process in the small boilers is constructed the experimental combustion device. There will investigate the impact of cooling intensity of the combustion chamber on the combustion process and emissions. Arising specific requirements from the measurement will be the basis for the design of the pellet burner and for the setting of operating parameters to the trouble-free phytomass combustion was guaranteed.

Cool-flame Extinction During N-Alkane Droplet Combustion in Microgravity

Science.gov (United States)

Nayagam, Vedha; Dietrich, Daniel L.; Hicks, Michael C.; Williams, Forman A.

2014-01-01

Recent droplet combustion experiments onboard the International Space Station (ISS) have revealed that large n-alkane droplets can continue to burn quasi-steadily following radiative extinction in a low-temperature regime, characterized by negative-temperaturecoefficient (NTC) chemistry. In this study we report experimental observations of n-heptane, n-octane, and n-decane droplets of varying initial sizes burning in oxygen/nitrogen/carbon dioxide and oxygen/helium/nitrogen environments at 1.0, 0.7, and 0.5 atmospheric pressures. The oxygen concentration in these tests varied in the range of 14% to 25% by volume. Large n-alkane droplets exhibited quasi-steady low-temperature burning and extinction following radiative extinction of the visible flame while smaller droplets burned to completion or disruptively extinguished. A vapor-cloud formed in most cases slightly prior to or following the "cool flame" extinction. Results for droplet burning rates in both the hot-flame and cool-flame regimes as well as droplet extinction diameters at the end of each stage are presented. Time histories of radiant emission from the droplet captured using broadband radiometers are also presented. Remarkably the "cool flame" extinction diameters for all the three n-alkanes follow a trend reminiscent of the ignition delay times observed in previous studies. The similarities and differences among the n-alkanes during "cool flame" combustion are discussed using simplified theoretical models of the phenomenon

Improving the performance and emission characteristics of a single cylinder diesel engine having reentrant combustion chamber using diesel and Jatropha methyl esters.

Science.gov (United States)

Premnath, S; Devaradjane, G

2015-11-01

The emissions from the Compression ignition (CI) engines introduce toxicity to the atmosphere. The undesirable carbon deposits from these engines are realized in the nearby static or dynamic systems such as vehicles, inhabitants, etc. The objective of this research work is to improve the performance and emission characteristics of a diesel engine in the modified re-entrant combustion chamber using a diesel and Jatropha methyl ester blend (J20) at three different injection pressures. From the literature, it is revealed that the shape of the combustion chamber and the fuel injection pressure have an impact on the performance and emission parameters of the CI engine. In this work, a re-entrant combustion chamber with three different fuel injection pressures (200, 220 and 240bars) has been used in the place of the conventional hemispherical combustion chamber for diesel and J20. From the experimental results, it is found that the re-entrant chamber improves the brake thermal efficiency of diesel and J20 in all the tested conditions. It is also found that the 20% blend of Jatropha methyl ester showed 4% improvement in the brake thermal efficiency in the re-entrant chamber at the maximum injection pressure. Environmental safety directly relates to the reduction in the undesirable effects on both living and non-living things. Currently environmental pollution is of major concern. Even with the stringent emission norms new methods are required to reduce the harmful effects from automobiles. The toxicity of carbon monoxide (CO) is well known. In the re-entrant combustion chamber, the amount of CO emission is reduced by 26% when compared with the conventional fuel operation of the engine. Moreover, the amount of smoke is reduced by 24% and hydrocarbons (HC) emission by 24%. Thus, the modified re-entrant combustion chamber reduces harmful pollutants such as unburned HC and CO as well as toxic smoke emissions. Copyright © 2015 Elsevier Inc. All rights reserved.

A refrigerated web camera for photogrammetric video measurement inside biomass boilers and combustion analysis.

Science.gov (United States)

Porteiro, Jacobo; Riveiro, Belén; Granada, Enrique; Armesto, Julia; Eguía, Pablo; Collazo, Joaquín

2011-01-01

This paper describes a prototype instrumentation system for photogrammetric measuring of bed and ash layers, as well as for flying particle detection and pursuit using a single device (CCD) web camera. The system was designed to obtain images of the combustion process in the interior of a domestic boiler. It includes a cooling system, needed because of the high temperatures in the combustion chamber of the boiler. The cooling system was designed using CFD simulations to ensure effectiveness. This method allows more complete and real-time monitoring of the combustion process taking place inside a boiler. The information gained from this system may facilitate the optimisation of boiler processes.

Three-dimensional simulation of flow and combustion for pulverised coal injection

Energy Technology Data Exchange (ETDEWEB)

Guo, B.Y.; Zulli, P.; Rogers, H.; Mathieson, J.G.; Yu, A.B. [BlueScope Steel Research, Port Kembla, NSW (Australia)

2005-07-01

A three-dimensional numerical model of pulverised coal injection has been developed for simulating coal flow and combustion in the tuyere and raceway of a blast furnace. The model has been used to simulate previously reported combustion tests, which feature an inclined co-axial lance with an annular cooling gas. The predicted coal burnout agrees well with that measured for three coals with volatile contents and particle size ranging between 20.2-36.4% and particle sizes 1-200 {mu}m. Many important phenomena including flow asymmetry, recirculating flow and particle dispersion in the combustion chamber have been predicted. The current model can reproduce the experimental observations including the effects on burnout of coal flowrate and the introduction of methane for lance cooling.

Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Silicided niobium alloy (C103) combustion chambers have been used extensively in both NASA and DoD liquid rocket propulsion systems. Niobium alloys offer a good...

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

Combustion chamber heat transfer characterization of LOX/hydrocarbon-type propellants

Science.gov (United States)

Schoenman, Leonard

1987-01-01

The gas-side heat transfer rates for LOX/propane and LOX/ethanol are experimentally characterized using a 1000 lb thrust water-cooled calorimeter chamber. The effects of injector element type and fuel film cooling are defined as a function of mixture ratio. The interaction of fuel injected through the resonator cavities on heat transfer and wall soot buildup are displayed as a function of time, axial distance, fuel coolant flow rate, and mixture ratio. Comparisons between clean-burning ethanol and sooting propane show a large difference between the two fuels and significantly higher than expected heat flux levels for ethanol in the throat region.

Low emission internal combustion engine

Science.gov (United States)

Karaba, Albert M.

1979-01-01

A low emission, internal combustion compression ignition engine having a cylinder, a piston movable in the cylinder and a pre-combustion chamber communicating with the cylinder near the top thereof and in which low emissions of NO.sub.x are achieved by constructing the pre-combustion chamber to have a volume of between 70% and 85% of the combined pre-chamber and main combustion chamber volume when the piston is at top dead center and by variably controlling the initiation of fuel injection into the pre-combustion chamber.

Internal combustion engine

Science.gov (United States)

Baker, Quentin A.; Mecredy, Henry E.; O'Neal, Glenn B.

1991-01-01

An improved engine is provided that more efficiently consumes difficult fuels such as coal slurries or powdered coal. The engine includes a precombustion chamber having a portion thereof formed by an ignition plug. The precombustion chamber is arranged so that when the piston is proximate the head, the precombustion chamber is sealed from the main cylinder or the main combustion chamber and when the piston is remote from the head, the precombustion chamber and main combustion chamber are in communication. The time for burning of fuel in the precombustion chamber can be regulated by the distance required to move the piston from the top dead center position to the position wherein the precombustion chamber and main combustion chamber are in communication.

Residual gas analysis of a cryostat vacuum chamber during the cool down of SST - 1 superconducting magnet field coil

International Nuclear Information System (INIS)

Semwal, P.; Joshi, K.S.; Thankey, P.L.; Pathan, F.S.; Raval, D.C.; Patel, R.J.; Pathak, H.A.

2005-01-01

One of the most important feature of Steady state Superconducting Tokamak -1 (SST-l) is the Nb-Ti superconducting magnet field coils. The coils will be kept in a high vacuum chamber (Cryostat) and liquid Helium will be flown through it to cool it down to its critical temperature of 4.5K. The coil along with its hydraulics has four types of joints (1) Stainless Steel (S.S.) to Copper (Cu) weld joints (2) S. S. to S. S. weld joints (3) Cu to Cu brazed joints and (4) G-10 to S. S. joints with Sti-cast as the binding material. The joints were leak tested with a Helium mass spectrometer leak detector in vacuum as well as in sniffer mode. However during the cool-down of the coil, these joints may develop leaks. This would deteriorate the vacuum inside the cryostat and coil cool-down would subsequently become more difficult. To study the effect of cooling on the vacuum condition of the Cryostat, a dummy Cryostat chamber was fabricated and a toroidal Field (TF) magnet was kept inside this chamber and cooled down to 4.5 K.A residual gas analyzer (RGA) was connected to the Cryostat chamber to study the behaviour of major gases inside this chamber with temperature. An analysis of the RGA data acquired during the coo-down has been presented in this chamber. (author)

Three-step approach for prediction of limit cycle pressure oscillations in combustion chambers of gas turbines

Science.gov (United States)

Iurashev, Dmytro; Campa, Giovanni; Anisimov, Vyacheslav V.; Cosatto, Ezio

2017-11-01

Currently, gas turbine manufacturers frequently face the problem of strong acoustic combustion driven oscillations inside combustion chambers. These combustion instabilities can cause extensive wear and sometimes even catastrophic damages to combustion hardware. This requires prevention of combustion instabilities, which, in turn, requires reliable and fast predictive tools. This work presents a three-step method to find stability margins within which gas turbines can be operated without going into self-excited pressure oscillations. As a first step, a set of unsteady Reynolds-averaged Navier-Stokes simulations with the Flame Speed Closure (FSC) model implemented in the OpenFOAM® environment are performed to obtain the flame describing function of the combustor set-up. The standard FSC model is extended in this work to take into account the combined effect of strain and heat losses on the flame. As a second step, a linear three-time-lag-distributed model for a perfectly premixed swirl-stabilized flame is extended to the nonlinear regime. The factors causing changes in the model parameters when applying high-amplitude velocity perturbations are analysed. As a third step, time-domain simulations employing a low-order network model implemented in Simulink® are performed. In this work, the proposed method is applied to a laboratory test rig. The proposed method permits not only the unsteady frequencies of acoustic oscillations to be computed, but the amplitudes of such oscillations as well. Knowing the amplitudes of unstable pressure oscillations, it is possible to determine how these oscillations are harmful to the combustor equipment. The proposed method has a low cost because it does not require any license for computational fluid dynamics software.

Piston surface heat transfer during combustion in large marine diesel engines

DEFF Research Database (Denmark)

Jensen, Michael Vincent; Walther, Jens Honore

2010-01-01

In the design process of large marine diesel engines information on the maximum heat load on the piston surface experienced during the engine cycle is an important parameter. The peak heat load occurs during combustion when hot combustion products impinge on the piston surface. Although the maximum...... heat load is only present for a short time of the total engine cycle, it is a severe thermal load on the piston surface. At the same time, cooling of the piston crown is generally more complicated than cooling of the other components of the combustion chamber. This can occasionally cause problems...... with burning off piston surface material. In this work the peak heat load on the piston surface of large marine diesel engines during combustion was investigated. Measurements of the instantaneous surface temperature and surface heat flux on pistons in large marine engines are difficult due to expensive...

A Refrigerated Web Camera for Photogrammetric Video Measurement inside Biomass Boilers and Combustion Analysis

Directory of Open Access Journals (Sweden)

Enrique Granada

2011-01-01

Full Text Available This paper describes a prototype instrumentation system for photogrammetric measuring of bed and ash layers, as well as for flying particle detection and pursuit using a single device (CCD web camera. The system was designed to obtain images of the combustion process in the interior of a domestic boiler. It includes a cooling system, needed because of the high temperatures in the combustion chamber of the boiler. The cooling system was designed using CFD simulations to ensure effectiveness. This method allows more complete and real-time monitoring of the combustion process taking place inside a boiler. The information gained from this system may facilitate the optimisation of boiler processes.

Rotary combustion device

NARCIS (Netherlands)

2008-01-01

Rotary combustion device (1) with rotary combustion chamber (4). Specific measures are taken to provide ignition of a combustible mixture. It is proposed that a hollow tube be provided coaxially with the axis of rotation (6), so that a small part of the mixture is guided into the combustion chamber.

Application of C/C composites to the combustion chamber of rocket engines. Part 1: Heating tests of C/C composites with high temperature combustion gases

Science.gov (United States)

Tadano, Makoto; Sato, Masahiro; Kuroda, Yukio; Kusaka, Kazuo; Ueda, Shuichi; Suemitsu, Takeshi; Hasegawa, Satoshi; Kude, Yukinori

1995-04-01

Carbon fiber reinforced carbon composite (C/C composite) has various superior properties, such as high specific strength, specific modulus, and fracture strength at high temperatures of more than 1800 K. Therefore, C/C composite is expected to be useful for many structural applications, such as combustion chambers of rocket engines and nose-cones of space-planes, but C/C composite lacks oxidation resistivity in high temperature environments. To meet the lifespan requirement for thermal barrier coatings, a ceramic coating has been employed in the hot-gas side wall. However, the main drawback to the use of C/C composite is the tendency for delamination to occur between the coating layer on the hot-gas side and the base materials on the cooling side during repeated thermal heating loads. To improve the thermal properties of the thermal barrier coating, five different types of 30-mm diameter C/C composite specimens constructed with functionally gradient materials (FGM's) and a modified matrix coating layer were fabricated. In this test, these specimens were exposed to the combustion gases of the rocket engine using nitrogen tetroxide (NTO) / monomethyl hydrazine (MMH) to evaluate the properties of thermal and erosive resistance on the thermal barrier coating after the heating test. It was observed that modified matrix and coating with FGM's are effective in improving the thermal properties of C/C composite.

Development of Novel Fe-Based Coating Systems for Internal Combustion Engines

Science.gov (United States)

Bobzin, K.; Öte, M.; Königstein, T.; Dröder, K.; Hoffmeister, H.-W.; Mahlfeld, G.; Schläfer, T.

2018-04-01

Nowadays, combustion engines are the most common way to power vehicles. Thereby, losses occur due to cooling, exhaust gas and friction. With regard to frictional losses, highest potentials for optimization can be found in the tribological system of the inner surface of combustion chamber and piston ring. Besides friction, corrosive stress increases, e.g., due to utilization of exhaust gas recovery. In order to save energy, reduce emissions and enhance the life span of combustion engines, the demand for innovative coating material systems, especially for the inner surface of combustion chamber, increases. This study focuses on the development of innovative iron-based coating materials for the combustion chamber. As a first step, the plasma transferred wire arc and rotating single wire arc (RSW) technologies were compared using 0.8% C-steel as a reference. Subsequently, RSW was used for coating deposition using an innovative iron-based feedstock material. In order to improve wear and corrosion resistance, boron and chromium were added to the feedstock material. After deposition, different honing topographies were manufactured and compared under tribological load. Furthermore, electrochemical corrosion tests were conducted using an electrolyte simulating the exhaust gas concentrate. Especially with regard to corrosion, the novel coating system FeCrBMn showed promising results.

Development of Novel Fe-Based Coating Systems for Internal Combustion Engines

Science.gov (United States)

Bobzin, K.; Öte, M.; Königstein, T.; Dröder, K.; Hoffmeister, H.-W.; Mahlfeld, G.; Schläfer, T.

2018-02-01

Nowadays, combustion engines are the most common way to power vehicles. Thereby, losses occur due to cooling, exhaust gas and friction. With regard to frictional losses, highest potentials for optimization can be found in the tribological system of the inner surface of combustion chamber and piston ring. Besides friction, corrosive stress increases, e.g., due to utilization of exhaust gas recovery. In order to save energy, reduce emissions and enhance the life span of combustion engines, the demand for innovative coating material systems, especially for the inner surface of combustion chamber, increases. This study focuses on the development of innovative iron-based coating materials for the combustion chamber. As a first step, the plasma transferred wire arc and rotating single wire arc (RSW) technologies were compared using 0.8% C-steel as a reference. Subsequently, RSW was used for coating deposition using an innovative iron-based feedstock material. In order to improve wear and corrosion resistance, boron and chromium were added to the feedstock material. After deposition, different honing topographies were manufactured and compared under tribological load. Furthermore, electrochemical corrosion tests were conducted using an electrolyte simulating the exhaust gas concentrate. Especially with regard to corrosion, the novel coating system FeCrBMn showed promising results.

Calculation of gas temperature at the outlet of the combustion chamber and in the air-gas channel of a gas-turbine unit by data of acceptance tests in accordance with ISO

Science.gov (United States)

Kostyuk, A. G.; Karpunin, A. P.

2016-01-01

This article describes a high accuracy method enabling performance of the calculation of real values of the initial temperature of a gas turbine unit (GTU), i.e., the gas temperature at the outlet of the combustion chamber, in a situation where manufacturers do not disclose this information. The features of the definition of the initial temperature of the GTU according to ISO standards were analyzed. It is noted that the true temperatures for high-temperature GTUs is significantly higher than values determined according to ISO standards. A computational procedure for the determination of gas temperatures in the air-gas channel of the gas turbine and cooling air consumptions over blade rims is proposed. As starting equations, the heat balance equation and the flow mixing equation for the combustion chamber are assumed. Results of acceptance GTU tests according to ISO standards and statistical dependencies of required cooling air consumptions on the gas temperature and the blade metal are also used for calculations. An example of the calculation is given for one of the units. Using a developed computer program, the temperatures in the air-gas channel of certain GTUs are calculated, taking into account their design features. These calculations are performed on the previously published procedure for the detailed calculation of the cooled gas turbine subject to additional losses arising because of the presence of the cooling system. The accuracy of calculations by the computer program is confirmed by conducting verification calculations for the GTU of the Mitsubishi Comp. and comparing results with published data of the company. Calculation data for temperatures were compared with the experimental data and the characteristics of the GTU, and the error of the proposed method is estimated.

Energy convergence of shock waves and its destruction mechanism in cone-roof combustion chambers

International Nuclear Information System (INIS)

Xu, Han; Yao, Anren; Yao, Chunde; Gao, Jian

2016-01-01

Highlights: • Experiments with simulations are designed to probe into engine severe knock. • Energy convergence at central and edge region is observed in closed-limited space. • Modes with different intensities and mechanism of energy convergence are revealed. • Chamber shape and equivalence ratio can affect the energy convergence. • The destruction effects of energy convergence on pistons are recognized. - Abstract: Energy convergence is considered as an important phenomenon in internal combustion engines under severe knock, in which shock waves caused by violent combustion may aggregate the energy released by fuel burning to damage engine parts like pistons and spark plugs easily. In order to reveal such convergence mechanism and its destruction effects, a novel detonation bomb experiment combined with numerical simulations are conducted. In bomb experiments, a detonation wave is forcibly introduced into a clearance-variable cone-roof combustion chamber by a high energy spark ignition. Four pressure transducers were installed in different positions to monitor the energy convergence. Combined with the experiments, numerical simulations were conducted to reveal the convergence modes and mechanisms. Finally, destruction samples were presented to validate this research. It’s found that the energy convergence of shock waves always occurs in middle and edge region, which are vulnerable to be damaged. Three modes of energy convergence are concluded for middle region while several ways of energy convergence are concluded for edge region, which are all related with the chamber shape and may result in different levels of convergence. It’s also found that though detonation strength (knock intensity) can be changed by both equivalence ratios and initial pressures, only the equivalence ratios can change the convergence modes while the initial pressures cannot.

Ultra-low pollutant emission combustion method and apparatus

International Nuclear Information System (INIS)

Khinkis, M.J.

1992-01-01

This patent describes a method for ultra-low pollutant emission combustion of fossil fuel. It comprises: introducing into a primary combustion chamber a first fuel portion of about 1 percent to about 20 percent of a total fuel to be combusted; introducing primary combustion air into the primary combustion chamber; introducing a first portion of water into the primary combustion chamber, having a first water heat capacity equivalent to a primary combustion air heat capacity of one of a primary combustion air amount of about 10 percent to about 60 percent of the first stoichiometirc requirement for complete combustion of the first fuel portion and an excess primary combustion air amount of about 20 percent to about 150 percent of the first stoichiometric requirement for complete combustion of the first fuel portion; burning the first fuel portion with the primary combustion air in the primary combustion chamber at a temperature abut 2000 degrees F to about 2700 degrees F producing initial combustion products; passing the initial combustion products into a secondary combustion chamber; introducing into the secondary combustion chamber a second fuel portion of about 80 percent to about 99 percent of the total fuel to be combusted; introducing secondary combustion air into the secondary combustion chamber in an amount of about 105 percent to about 130 percent of a second stoichiometric requirement for complete combustion of the second fuel portion; introducing a second portion of water into the secondary combustion chamber; burning the second fuel portion and any remaining fuel in the initial combustion products; passing the final combustion products into a dilution chamber; introducing dilution air into the dilution chamber; discharging the ultra-low pollutant emission vitiated air form the dilution chamber

Experimental determination of temperatures of the inner wall of a boiler combustion chamber for the purpose of verification of a CFD model

Directory of Open Access Journals (Sweden)

Petr Trávníček

2011-01-01

Full Text Available The paper focuses on the non-destructive method of determination of temperatures in the boiler combustion chamber. This method proves to be significant mainly as regards CFD (Computational Fluid Dynamics simulations of combustion processes, in case of which it is subsequently advisable to verify the data calculated using CFD software application with the actually measured data. Verification of the method was based on usage of reference combustion equipment (130 kW which performs combustion of a mixture of waste sawdust and shavings originating in the course of production of wooden furniture. Measuring of temperatures inside the combustion chamber is – considering mainly the high temperature values – highly demanding and requires a special type of temperature sensors. Furthermore, as regards standard operation, it is not possible to install such sensors without performing structural alterations of the boiler. Therefore, for the purpose of determination of these temperatures a special experimental device was constructed while exploiting a thermal imaging system used for monitoring of the surface temperature of outer wall of the reference boiler. Temperatures on the wall of the boiler combustion chamber were determined on the basis of data measured using the experimental device as well as data from the thermal imaging system. These values might serve for verification of the respective CFD model of combustion equipment.

An experimental and numerical investigation of the combustion characteristics of a dual fuel engine with a swirl chamber

Energy Technology Data Exchange (ETDEWEB)

Liu, C.; Karim, G.A.; Xiao, F.; Sohrabi, A. [Calgary Univ., AB (Canada). Schulich School of Engineering, Mechanical and Manufacturing Dept.

2007-07-01

The results of an experimental investigation of the performance of a small bore engine with a swirl chamber when operating as a dual fuel engine with commercial methane as the gaseous fuel were presented in this paper. The experiment involved using a 3-dimensional computational fluid dynamics model to predict the performance of the engine. A detailed chemical kinetics for the gaseous fuel component, consisting primarily of methane and a reduced detailed chemical kinetics for the diesel fuel while considering the turbulent combustion processes an associated performance of a dual fuel engine with a swirl chamber were incorporated in the simulation. The study experimentally and numerically investigated the effects of changes in the quantities of the liquid fuel pilot and gaseous fuels on the combustion processes, engine performance, cyclic variations, and emissions. The paper discussed the experimental approach and results. It also discussed the simulation of the dual fuel engine combustion process. It was concluded that dual fuel combustion was an effective method to burn a gaseous fuel-air mixture with a low energy density. 9 refs., 6 figs.

Energy Converter with Inside Two, Three, and Five Connected H2/Air Swirling Combustor Chambers: Solar and Combustion Mode Investigations

Directory of Open Access Journals (Sweden)

Angelo Minotti

2016-06-01

Full Text Available This work reports the performance of an energy converter characterized by an emitting parallelepiped element with inside two, three, or five swirling connected combustion chambers. In particular, the idea is to adopt the heat released by H2/air combustion, occurring in the connected swirling chambers, to heat up the emitting surfaces of the thermally-conductive emitting parallelepiped brick. The final goal consists in obtaining the highest emitting surface temperature and the highest power delivered to the ambient environment, with the simultaneous fulfillment of four design constraints: dimension of the emitting surface fixed to 30 × 30 mm2, solar mode thermal efficiency greater than 20%, emitting surface peak temperature T > 1000 K, and its relative ∆T < 100 K in the combustion mode operation. The connected swirling meso-combustion chambers, inside the converter, differ only in their diameters. Combustion simulations are carried out adopting 500 W of injected chemical power, stoichiometric conditions, and detailed chemistry. All provide high chemical efficiency, η > 99.9%, and high peak temperature, but the emitting surface ∆T is strongly sensitive to the geometrical configuration. The present work is related to the “EU-FP7-HRC-Power” project, aiming at developing micro-meso hybrid sources of power, compatible with a thermal/electrical conversion by thermo-photovoltaic cells.

Investigating the reactivity controlled compression ignition (RCCI) combustion strategy in a natural gas/diesel fueled engine with a pre-chamber

International Nuclear Information System (INIS)

Salahi, Mohammad Mahdi; Esfahanian, Vahid; Gharehghani, Ayatallah; Mirsalim, Mostafa

2017-01-01

Highlights: • A novel combustion strategy, RCCI with a pre-chamber, is proposed and investigated. • The proposed strategy extends the RCCI operating range to use less intake air temperatures. • The new concept extends the RCCI operating range to use lower portions of the active fuel. • The proposed strategy is sensitive to engine load and is more efficient for high loads. - Abstract: Reactivity controlled compression ignition (RCCI) concept has been proven to be a promising combustion mode for the next generations of internal combustion engines. This strategy is still subject of extensive studies to overcome its operational limitations. In the present work, the effect of using a pre-chamber to extend some operating ranges in a RCCI engine is investigated using coupled multidimensional computational fluid dynamics (CFD) with detailed chemical kinetic mechanisms. To accomplish this, the combustion and flow field in a single cylinder engine with a pre-chamber, working in RCCI mode and fueled with natural gas/diesel are numerically modeled. Experimental data is used to validate the simulation results and then, combustion characteristics and engine emissions in some various operating regions, in terms of initial temperature, fuel equivalence ratio and portions of the two fuels are discussed. The results reveal that the proposed strategy provides the ability to extend the engine operating ranges to use lower intake temperatures, even to 50 K lower for some cases, and also using a larger portion of natural gas instead of diesel fuel. On the other hand, the new strategy could result in incomplete combustion and formation of related emissions in low loads, but for higher engine loads it shows better combustion characteristics.

Modeling of Uneven Flow and Electromagnetic Field Parameters in the Combustion Chamber of Liquid Rocket Engine with a Near-wall Layer Available

Directory of Open Access Journals (Sweden)

A. V. Rudinskii

2015-01-01

Full Text Available The paper concerns modeling of an uneven flow and electromagnetic field parameters in the combustion chamber of the liquid rocket engine with a near-wall layer available.The research objective was to evaluate quantitatively influence of changing model chamber mode of the liquid rocket engine on the electro-physical characteristics of the hydrocarbon fuel combustion by-products.The main method of research was based on development of a final element model of the flowing path of the rocket engine chamber and its adaptation to the boundary conditions.The paper presents a developed two-dimensional non-stationary mathematical model of electro-physical processes in the liquid rocket engine chamber using hydrocarbon fuel. The model takes into consideration the features of a gas-dynamic contour of the engine chamber and property of thermo-gas-dynamic characteristics of the ionized products of combustion of hydrocarbonic fuel. Distributions of magnetic field intensity and electric conductivity received and analyzed taking into account a low-temperature near-wall layer. Special attention is paid to comparison of obtained calculation values of the electric current, which is taken out from intrachamber space of the engine with earlier published data of other authors.

Combustion Stability Verification for the Thrust Chamber Assembly of J-2X Developmental Engines 10001, 10002, and 10003

Science.gov (United States)

Morgan, C. J.; Hulka, J. R.; Casiano, M. J.; Kenny, R. J.; Hinerman, T. D.; Scholten, N.

2015-01-01

The J-2X engine, a liquid oxygen/liquid hydrogen propellant rocket engine available for future use on the upper stage of the Space Launch System vehicle, has completed testing of three developmental engines at NASA Stennis Space Center. Twenty-one tests of engine E10001 were conducted from June 2011 through September 2012, thirteen tests of the engine E10002 were conducted from February 2013 through September 2013, and twelve tests of engine E10003 were conducted from November 2013 to April 2014. Verification of combustion stability of the thrust chamber assembly was conducted by perturbing each of the three developmental engines. The primary mechanism for combustion stability verification was examining the response caused by an artificial perturbation (bomb) in the main combustion chamber, i.e., dynamic combustion stability rating. No dynamic instabilities were observed in the TCA, although a few conditions were not bombed. Additional requirements, included to guard against spontaneous instability or rough combustion, were also investigated. Under certain conditions, discrete responses were observed in the dynamic pressure data. The discrete responses were of low amplitude and posed minimal risk to safe engine operability. Rough combustion analyses showed that all three engines met requirements for broad-banded frequency oscillations. Start and shutdown transient chug oscillations were also examined to assess the overall stability characteristics, with no major issues observed.

Soot temperature and KL factor for biodiesel and diesel spray combustion in a constant volume combustion chamber

KAUST Repository

Zhang, Ji

2013-07-01

This paper presents measurements of the soot temperature and KL factor for biodiesel and diesel combustion in a constant volume chamber using a two-color technique. This technique uses a high-speed camera coupled with two narrowband filters (550. nm and 650. nm, 10. nm FWHM). After calibration, statistical analysis shows that the uncertainty of the two-color temperature is less than 5%, while it is about 50% for the KL factor. This technique is then applied to the spray combustion of biodiesel and diesel fuels under an ambient oxygen concentration of 21% and ambient temperatures of 800, 1000 and 1200. K. The heat release result shows higher energy utilization efficiency for biodiesel compared to diesel under all conditions; meanwhile, diesel shows a higher pressure increase due to its higher heating value. Biodiesel yields a lower temperature inside the flame area, a longer soot lift-off length, and a smaller soot area compared to diesel. Both the KL factor and the total soot with biodiesel are lower than with diesel throughout the entire combustion process, and this difference becomes larger as the ambient temperature decreases. Biodiesel shows approximately 50-100. K lower temperatures than diesel at the quasi-steady stage for 1000 and 1200. K ambient temperature, while diesel shows a lower temperature than biodiesel at 800. K ambient. This result may raise the question of how important the flame temperature is in explaining the higher NO. x emissions often observed during biodiesel combustion. Other factors may also play an important role in controlling NO. x emissions. Both biodiesel and diesel temperature measurements show a monotonic dependence on the ambient temperature. However, the ambient temperature appears to have a more significant effect on the soot formation and oxidation in diesel combustion, while biodiesel combustion soot characteristics shows relative insensitivity to the ambient temperature. © 2013 Elsevier Ltd.

Spray combustion of Jet-A and diesel fuels in a constant volume combustion chamber

KAUST Repository

Jing, Wei

2015-01-01

This work investigates the spray combustion of Jet-A fuel in an optical constant-volume combustion chamber under different ambient initial conditions. Ambient temperature was varied at 800 K, 1000 K, and 1200 K and five different ambient O2 concentrations were used, spanning 10-21%. These ambient conditions can be used to mimic practical diesel engine working conditions under different fuel injection timings and exhaust gas recirculation (EGR) levels. Both transient and quasi-steady state analyses were conducted. The transient analysis focused on the flame development from the beginning to the end of the combustion process, illustrating how the flame structure evolves with time. The quasi-steady state analysis concentrated on the stable flame structure and compared the flame emissions in terms of spatially integrated intensity, flame effective area, and intensity per pixel. The transient analysis was based on measurements using high-speed imaging of both OH∗ chemiluminescence and broadband natural luminosity (NL). For the quasi-steady state analysis, three flame narrow-band emissions (OH∗ at 310 nm, Band A at 430 nm and Band B at 470 nm) were captured using an ICCD camera. Based on the current Jet-A data and diesel data obtained from previous experiments, a comparison between Jet-A and diesel was made in terms of flame development during the transient state and spatially integrated intensity, flame effective area, and intensity per pixel during the quasi-steady state. For the transient results, Jet-A shares a similar flame development trend to diesel, but featuring a narrower region of NL and a wider region of OH∗ with the increase of ambient temperature and O2 concentration. The soot cloud is oxidized more quickly for Jet-A than diesel at the end of combustion, evident by comparing the area of NL, especially under high O2 concentration. The quasi-steady state results suggest that soot is oxidized effectively under high O2 concentration conditions by the

Passive cooling of condensate chambers as retrofitting measure in boiling water reactors; Passive Kuehlung der Kondensationskammern in Siedewasserreaktoren als Nachruestmassnahme

Energy Technology Data Exchange (ETDEWEB)

Freis, Daniel; Nachtrodt, Frederik; Sporn, Michael; Tietsch, Wolfgang; Sassen, Felix [Westinghouse Electric Germany GmbH, Mannheim (Germany)

2012-11-01

Westinghouse Electric Germany GmbH has developed a concept for passive cooling of condensate chambers of BWR-type reactors. Due to its compactness the system is feasible as retrofitting measure. The passive condensate chamber cooling system is based on a cooling module with ascending and down pipe that are connected with the evaporation condenser to form a cooling circuit. Based on the consequent use of high-effective heat transport mechanisms, as boiling, condensation without non-condensable gases and mass transport a high cooling performance and compact construction is possible. The system is completely passive and completely diverse to existing active cooling systems. In the frame of a true-scale experiment the significant cooling performance was demonstrated. RELAP5 calculations confirmed the functionality of the cooling module.

Matériaux architecturés pour refroidissement par transpiration : application aux chambres de combustion

OpenAIRE

Pinson , Sébastien

2016-01-01

In order to cool aero-engine combustion chambers as efficiently as possible, there is today a special interest given to transpiration cooling technology. The cooling air flows through a porous liner in which a large amount of heat can be exchanged by convection. The air injection could then take benefit of the pore distribution to form a more homogeneous protective boundary layer.Partially sintered metallic materials are potential candidates to form these porous liners. The present work focus...

Combustor nozzle for a fuel-flexible combustion system

Science.gov (United States)

Haynes, Joel Meier [Niskayuna, NY; Mosbacher, David Matthew [Cohoes, NY; Janssen, Jonathan Sebastian [Troy, NY; Iyer, Venkatraman Ananthakrishnan [Mason, OH

2011-03-22

A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

Analysis of the effects of combining air separation with combustion in a zero emissions (ZEITMOP) cycle

International Nuclear Information System (INIS)

Foy, Kirsten; McGovern, Jim

2007-01-01

The ZEITMOP cycle is a zero emissions (oxyfuel) power plant cycle proposed by Evgeny Yantovski that uses oxygen ion transport membranes to extract the oxygen required for combustion from air. A current proposed configuration of the cycle requires an oxygen ion transport membrane air separation unit operating at 920 deg. C and a separate combustion chamber operating at 1400 deg. C. If oxygen is consumed by a chemical reaction on the permeate side of an oxygen transport membrane, the oxygen flux is larger, so the air separation unit can be physically smaller. In addition, if this reaction is exothermic, the air separation unit is heated by the reaction, requiring no additional heating. Combustion fulfils both of these requirements, so combustion in the oxygen transport membrane air separation unit would allow a smaller air separation unit, which would also act as a combustion chamber. Unfortunately, a combustion temperature of 1400 deg. C will damage most oxygen transport membranes available today. However, new materials are continually being developed and investigated, so it may be possible to have an oxygen transport membrane chamber operating at 1400 deg. C in the short to medium term future. Alternatively the combustion chamber may be cooled, allowing it to operate at more realistic temperatures for currently available oxygen transport membranes. Controlling the operation temperature of the combined unit requires changing the mass flow rates of various streams of fluid in the cycle. This will have an effect on the work and heat transfers in the cycle. It is possible to calculate the theoretical effects of these changes in temperature. This paper presents an analysis investigating the impact of combining the air separator and the combustion chamber. The efficiency of the cycle was calculated at various operation temperatures for the combined oxygen transport membrane combustion chamber. The results were compared to the efficiency of the current cycle. The changes

Fabrication of High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner for Advanced Rocket Engines

Science.gov (United States)

Bhat, Biliyar N.; Greene, Sandra E.; Singh, Jogender

2016-01-01

This paper describes the process development for fabricating a high thermal conductivity NARloy-Z-Diamond composite (NARloy-Z-D) combustion chamber liner for application in advanced rocket engines. The fabrication process is challenging and this paper presents some details of these challenges and approaches used to address them. Prior research conducted at NASA-MSFC and Penn State had shown that NARloy-Z-40%D composite material has significantly higher thermal conductivity than the state of the art NARloy-Z alloy. Furthermore, NARloy-Z-40 %D is much lighter than NARloy-Z. These attributes help to improve the performance of the advanced rocket engines. Increased thermal conductivity will directly translate into increased turbopump power, increased chamber pressure for improved thrust and specific impulse. Early work on NARloy-Z-D composites used the Field Assisted Sintering Technology (FAST, Ref. 1, 2) for fabricating discs. NARloy-Z-D composites containing 10, 20 and 40vol% of high thermal conductivity diamond powder were investigated. Thermal conductivity (TC) data. TC increased with increasing diamond content and showed 50% improvement over pure copper at 40vol% diamond. This composition was selected for fabricating the combustion chamber liner using the FAST technique.

Self-quenching streamer discharge in a wire chamber

International Nuclear Information System (INIS)

Alekseev, G.D.; Kruglov, V.V.; Khazins, D.M.

1982-01-01

A summary is given of the investigation of a new mode of operation of a wire chamber involving a self-quenching streamer discharge. The history of the question is briefly discussed. The main characteristics of the self-quenching mode and the influence of the composition and pressure of the gas mixture and the geometrical parameters of the chamber on the characteristics are described. The mechanism of a self-quenching streamer discharge is analyzed. Detectors working in this mode are described, and the prospects for its future use are discussed

Combustion means for solid fuels

Energy Technology Data Exchange (ETDEWEB)

Murase, D.

1987-09-23

A combustion device for solid fuel, suitable for coal, coke, charcoal, coal-dust briquettes etc., comprising:- a base stand with an opening therein, an imperforate heat resistant holding board locatable to close said opening; a combustion chamber standing on the base stand with the holding board forming the base of the combustion chamber; a wiper arm pivoted for horizontal wiping movement over the upper surface of the holding board; an inlet means at a lower edge of said chamber above the base stand, and/or in a surrounding wall of said chamber, whereby combustion air may enter as exhaust gases leave the combustion chamber; an exhaust pipe for the exhaust gases; generally tubular gas-flow heat-exchange ducting putting the combustion chamber and exhaust pipe into communication; and means capable of moving the holding board into and out of the opening for removal of ash or other residue. The invention can be used for a heating system in a house or in a greenhouse or for a boiler.

Heat transfer correlation models for electrospray evaporative cooling chambers of different geometry types

International Nuclear Information System (INIS)

Wang, Hsiu-Che; Mamishev, Alexander V.

2012-01-01

Development of future electronics for high speed computing requires a silent thermal management method capable of dissipating a broad range of heat generated from application-specific integrated circuits, while keeping the skin temperature below 45 °C. Electrospray evaporative cooling (ESEC) chambers show promise because of their ability to dissipate a broad range of heat within a relatively small size. However, the development and the optimization of ESEC chambers are currently restricted, in part due to the lack of sufficient empirical heat transfer correlations. This paper investigates empirical heat transfer correlations for ESEC chambers with three different geometry types. Since the unstable multi-jet behavior of an ESEC chamber is similar to that of a free-surface traditional impinging liquid jet, these correlations are based on the traditional impinging liquid jet’s empirical correlations, yet are modified to factor in the electric field effect. The results show that the heat transfer enhancement ratio correlations and the Nusselt number correlations for different ESEC chambers cover more than 83% of the experimental data, within ±10% deviation. The sensitivity analysis results and experimental data prove that the variation in the enhancement ratio is sensitive to that of the potential and the flow rate. It is not sensitive to the geometric factor of the same ESEC type. This paper presents a natural convection correlation for chip-scale, heated, flat surfaces when the Rayleigh number is below 3000. Further investigation is necessary to extend these heat transfer correlations to cover additional parameters for different thermal management applications. - Highlights: ► We develop empirical heat transfer correlations for electrospray evaporative cooling chambers. ► The developed heat transfer enhancement correlations fit more than 83% experimental data. ► The developed Nusselt number correlations fit more than 89% experimental data. ► We present a

Numerical study of heat transfer enhancement due to the use of fractal-shaped design for impingement cooling

Directory of Open Access Journals (Sweden)

Cai Lin

2017-01-01

Full Text Available This paper describes a numerical analysis of a heat transfer enhancement technique that introduces fractal-shaped design for impingement cooling. Based on the gas turbine combustion chamber cooling, a fractal-shaped nozzle is designed for the constant flow area in a single impingement cooling model. The incompressible Reynolds-averaged Navier-Stokes equations are applied to the system using CFD software. The numerical results are compared with the experiment results for array impingement cooling.

Spray combustion of Jet-A and diesel fuels in a constant volume combustion chamber

International Nuclear Information System (INIS)

Jing, Wei; Roberts, William L.; Fang, Tiegang

2015-01-01

This work investigates the spray combustion of Jet-A fuel in an optical constant-volume combustion chamber under different ambient initial conditions. Ambient temperature was varied at 800 K, 1000 K, and 1200 K and five different ambient O 2 concentrations were used, spanning 10–21%. These ambient conditions can be used to mimic practical diesel engine working conditions under different fuel injection timings and exhaust gas recirculation (EGR) levels. Both transient and quasi-steady state analyses were conducted. The transient analysis focused on the flame development from the beginning to the end of the combustion process, illustrating how the flame structure evolves with time. The quasi-steady state analysis concentrated on the stable flame structure and compared the flame emissions in terms of spatially integrated intensity, flame effective area, and intensity per pixel. The transient analysis was based on measurements using high-speed imaging of both OH ∗ chemiluminescence and broadband natural luminosity (NL). For the quasi-steady state analysis, three flame narrow-band emissions (OH ∗ at 310 nm, Band A at 430 nm and Band B at 470 nm) were captured using an ICCD camera. Based on the current Jet-A data and diesel data obtained from previous experiments, a comparison between Jet-A and diesel was made in terms of flame development during the transient state and spatially integrated intensity, flame effective area, and intensity per pixel during the quasi-steady state. For the transient results, Jet-A shares a similar flame development trend to diesel, but featuring a narrower region of NL and a wider region of OH ∗ with the increase of ambient temperature and O 2 concentration. The soot cloud is oxidized more quickly for Jet-A than diesel at the end of combustion, evident by comparing the area of NL, especially under high O 2 concentration. The quasi-steady state results suggest that soot is oxidized effectively under high O 2 concentration conditions by

The Energy Efficiency of Hot Water Production by Gas Water Heaters with a Combustion Chamber Sealed with Respect to the Room

Directory of Open Access Journals (Sweden)

Grzegorz Czerski

2014-08-01

Full Text Available This paper presents investigative results of the energy efficiency of hot water production for sanitary uses by means of gas-fired water heaters with the combustion chamber sealed with respect to the room in single-family houses and multi-story buildings. Additionally, calculations were made of the influence of pre-heating the air for combustion in the chimney and air supply system on the energy efficiency of hot water production. CFD (Computational Fluid Dynamics software was used for calculation of the heat exchange in this kind of system. The studies and calculations have shown that the use of gas water heaters with a combustion chamber sealed with respect to the room significantly increases the efficiency of hot water production when compared to traditional heaters. It has also been proven that the pre-heating of combustion air in concentric chimney and air supply ducts essentially improves the energy efficiency of gas appliances for hot water production.

Sleeve reaction chamber system

Science.gov (United States)

Northrup, M Allen [Berkeley, CA; Beeman, Barton V [San Mateo, CA; Benett, William J [Livermore, CA; Hadley, Dean R [Manteca, CA; Landre, Phoebe [Livermore, CA; Lehew, Stacy L [Livermore, CA; Krulevitch, Peter A [Pleasanton, CA

2009-08-25

A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

Combustion Chamber Deposits and PAH Formation in SI Engines Fueled by Producer Gas from Biomass Gasification

DEFF Research Database (Denmark)

Ahrenfeldt, Jesper; Henriksen, Ulrik Birk; Schramm, Jesper

2003-01-01

Investigations were made concerning the formation of combustion chamber deposits (CCD) in SI gas engines fueled by producer gas. The main objective was to determine and characterise CCD and PAH formation caused by the presence of the light tar compounds phenol and guaiacol in producer gas from...... on filters and a sorbent was used for collection of vapour phase aromatic compounds. The filters and sorbent were analysed for polycyclic aromatic hydrocarbons (PAH) formed during combustion. The measurements showed that there was no significant increase in particulate PAH emissions due to the tar compounds...

Correlation of photon beam motion with vacuum chamber cooling on the NSLS x-ray ring

International Nuclear Information System (INIS)

Johnson, E.D.; Fauchet, A.M.; Zhang, Xiaohao.

1991-01-01

The NSLS X-ray ring exhibits a direct correlation between photon beam motion, and distortion of the ring vacuum chamber induced by fluctuations in the cooling system. We have made long term measurements of photon beam vertical position, accelerator vacuum chamber motion, process water temperatures, and angular motions of the magnets around one superperiod of the NSLS x-ray ring. Short term transients in water temperature cause deflection of the ring vacuum chamber which have in turn been shown to induce very small angular rotations of the magnets, on the order of 10 micro-radians. A larger and more difficult to correct effect is the drift in beam position over the course of a fill. This problem has been shown to be related to the thermal gradients that develop across the vacuum chamber which, as a consequence of the configuration of the chamber cooling, depend upon stored current. Orbit simulations based upon the measured rotations are in agreement with the observed beam motions, and reveal that certain patterns of correlated motions of the magnets can produce much larger errors than random motion or concerted motion of all the magnets. During the course of these measurements global orbit feedback was installed, and found to significantly reduce the orbit errors which could not be corrected at their source

Dry low NOx combustion system with pre-mixed direct-injection secondary fuel nozzle

Science.gov (United States)

Zuo, Baifang; Johnson, Thomas; Ziminsky, Willy; Khan, Abdul

2013-12-17

A combustion system includes a first combustion chamber and a second combustion chamber. The second combustion chamber is positioned downstream of the first combustion chamber. The combustion system also includes a pre-mixed, direct-injection secondary fuel nozzle. The pre-mixed, direct-injection secondary fuel nozzle extends through the first combustion chamber into the second combustion chamber.

Combustion Chamber Deposits and PAH Formation in SI Engines Fueled by Producer Gas from Biomass Gasification

DEFF Research Database (Denmark)

Ahrenfeldt, Jesper; Henriksen, Ulrik Birk; Schramm, Jesper

2003-01-01

Investigations were made concerning the formation of combustion chamber deposits (CCD) in SI gas engines fueled by producer gas. The main objective was to determine and characterise CCD and PAH formation caused by the presence of the light tar compounds phenol and guaiacol in producer gas from an...

Appraisal of possible combustion hazards associated with a high-temperature gas-cooled reactor

International Nuclear Information System (INIS)

Palmer, H.B.; Sibulkin, M.; Strehlow, R.A.; Yang, C.H.

1978-03-01

The report presents a study of combustion hazards that may be associated with the High Temperature Gas Cooled Reactor (HTGR) in the event of a primary coolant circuit depressurization followed by water or air ingress into the prestressed concrete reactor vessel (PCRV). Reactions between graphite and steam or air produce the combustible gases H 2 and/or CO. When these gases are mixed with air in the containment vessel (CV), flammable mixtures may be formed. Various modes of combustion including diffusion or premixed flames and possibly detonation may be exhibited by these mixtures. These combustion processes may create high over-pressure, pressure waves, and very hot gases within the CV and hence may threaten the structural integrity of the CV or damage the instrumentation and control system installations within it. Possible circumstances leading to these hazards and the physical characteristics related to them are delineated and studied in the report

Industrial development of neutron detectors, fission chambers, self powered detectors, ionization chambers

International Nuclear Information System (INIS)

Constans, H.; Coville, P.; Guerre, J.

1975-01-01

Reactor control requires the determination of neutron flux at all times. The needed characteristics lead to use of several types of detectors: boron lined counters, boron lined ionization chambers, fission ionization chambers and self powered detectors. The principle of the reaction involved the fabrication requirements, the different modes of utilization and the characteristics obtained are examined for each detector. The problem of electric connections in the active area has been solved by developing ''integrated cables'' [fr

Investigating heat and temperature regime of the combustion chamber furnace screen of the TP 100A steam generator in the Varna thermal power plant

Energy Technology Data Exchange (ETDEWEB)

Mikhlevski, A; Buchinski, B; Dashkiev, Yu; Radzievski, V; Petkov, Kh [Kievski Politekhnicheski Institut (USSR)

1988-01-01

In the course of 10 year operation of six TP 100A steam generators 72 emergency operation interruptions occurred due to the piercing of screen pipes in the combustion chamber. According to investigations carried out by the NPO, CKT, VTI, KPI and Soyuzenergo institutes, the damage occurred mainly because of the destructive influence of external gas corrosion processes, overheating and fatigue of metallic pipes, as well as unstable heat and temperature regime in the combustion chamber. Large-scale measurements of the main thermodynamic parameters of the combustion chamber of the TP-100A steam generator were carried out in order to increase service life of screen pipes. It was found that the temperature of screen pipes increases 2.5 C/month because of deposition of sediments. Regular cleaning of screen pipes in intervals of 18 months is recommended as a very efficient means of prolonging their service life. 1 ref.

Hot-Fire Test Results of an Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged-Combustion Integrated Test Article

Science.gov (United States)

Hulka, J. R.; Protz, C. S.; Garcia, C. P.; Casiano, M. J.; Parton, J. A.

2016-01-01

combustion analysis model development. Hot-fire testing was conducted with main combustion chamber pressures ranging from 1400 to 2100 psia, and main combustion chamber mixture ratios ranging from 2.4 to 2.9. Different levels of fuel film cooling injected from the injector face were examined ranging from none to about 12% of the total fuel flow. This paper presents the hot-fire test results of the integrated test article. Combustion performance, stability, thermal, and compatibility characteristics of both the preburner and the thrust chamber are described. Another companion paper at this JANNAF meeting includes additional and more detailed test data regarding the combustion dynamics and stability characteristics.

Technologies for the treatment of the sulfur dioxide and nitrogen oxides generated by the combustion in open chamber; Tecnologias para el tratamiento de dioxido de azufre y oxidos de nitrogeno generados por la combustion en camara abierta

Energy Technology Data Exchange (ETDEWEB)

Salazar Villalpando, Maria Dolores [Instituto Mexicano del Petroleo, Mexico, D. F. (Mexico)

1993-12-31

In general terms, there are only three ways of avoiding the sulfur dioxide and the nitrogen oxides, generated by the combustion in open chamber, from contaminating the air; the first one is utilizing low sulfur and nitrogen content fuels, the second one is by controlling the parameters that affect the combustion and the third one to treat and/or clean the gases before exhausting them to the air. In this document, some of the treatments for diminishing the pollutant emissions generated by the combustion in open chamber, are presented. [Espanol] En terminos generales, solo existen 3 maneras de evitar que el dioxido de azufre y oxidos de nitrogeno generados por la combustion en camara abierta sigan contaminando el aire, la primera es utilizar un combustible de bajo contenido de azufre y nitrogeno, la segunda es controlar los parametros que afectan la combustion, y la tercera es tratar y/o limpiar los gases antes de emitirlos a la atmosfera. En este documento se presentan algunos tratamientos para disminuir las emisiones de contaminantes generados por la combustion en camara abierta.

Technologies for the treatment of the sulfur dioxide and nitrogen oxides generated by the combustion in open chamber; Tecnologias para el tratamiento de dioxido de azufre y oxidos de nitrogeno generados por la combustion en camara abierta

Energy Technology Data Exchange (ETDEWEB)

Salazar Villalpando, Maria Dolores [Instituto Mexicano del Petroleo, Mexico, D. F. (Mexico)

1992-12-31

In general terms, there are only three ways of avoiding the sulfur dioxide and the nitrogen oxides, generated by the combustion in open chamber, from contaminating the air; the first one is utilizing low sulfur and nitrogen content fuels, the second one is by controlling the parameters that affect the combustion and the third one to treat and/or clean the gases before exhausting them to the air. In this document, some of the treatments for diminishing the pollutant emissions generated by the combustion in open chamber, are presented. [Espanol] En terminos generales, solo existen 3 maneras de evitar que el dioxido de azufre y oxidos de nitrogeno generados por la combustion en camara abierta sigan contaminando el aire, la primera es utilizar un combustible de bajo contenido de azufre y nitrogeno, la segunda es controlar los parametros que afectan la combustion, y la tercera es tratar y/o limpiar los gases antes de emitirlos a la atmosfera. En este documento se presentan algunos tratamientos para disminuir las emisiones de contaminantes generados por la combustion en camara abierta.

A REVIEW OF MILD COMBUSTION AND OPEN FURNACE DESIGN CONSIDERATION

Directory of Open Access Journals (Sweden)

M.M. Noor

2012-12-01

Full Text Available Combustion is still very important to generate energy. Moderate or Intense Low-oxygen Dilution (MILD combustion is one of the best new technologies for clean and efficient combustion. MILD combustion has been proven to be a promising combustion technology in industrial applications with decreased energy consumption due to the uniformity of its temperature distribution. It is clean compared to traditional combustion due to producing low NOx and CO emissions. This article provides a review and discussion of recent research and developments in MILD. The issue and applications are summarized, with some suggestions presented on the upgrading and application of MILD in the future. Currently MILD combustion has been successfully applied in closed furnaces. The preheating of supply air is no longer required since the recirculation inside the enclosed furnace already self-preheats the supply air and self-dilutes the oxygen in the combustion chamber. The possibility of using open furnace MILD combustion will be reviewed. The design consideration for open furnace with exhaust gas re-circulation (EGR was discussed.

Proposal of a numerical modeling of reactive flows in combustion chambers of turbojet engines; Proposition d`une modelisation numerique des ecoulements reactifs dans les foyers de turboreacteurs

Energy Technology Data Exchange (ETDEWEB)

Ravet, F. [Rouen Univ., 76 - Mont-Saint-Aignan (France)]|[SNECMA, 77 - Moissy-Cramayel (France); Baudoin, Ch.; Schultz, J.L. [SNECMA, 77 - Moissy-Cramayel (France)

1996-12-31

Simplifying hypotheses are required when combustion and aerodynamic phenomena are considered simultaneously. In this paper, a turbulent combustion model is proposed, in which the combustion chemistry is reduced to a single reaction. In this way, only two variables are needed to describe the problem and combustion can be characterized by the consumption of one of the two reactive species. In a first step, the instantaneous consumption rate is obtained using the Lagrangian form of the mass fraction equation of the species under consideration, and by considering the equilibrium state only. This state is determined in order to preserve the consistency with results that should be obtained using a complete kinetics scheme. In a second step, the average rate is determined using the instantaneous consumption term and a probabilistic density function. This model was tested on various configurations and in particular on an experimental main chamber and on a reheating chamber. Results indicate that this model could be used to predict temperature levels inside these combustion chambers. Other applications, like the prediction of pollutant species emission can be considered. (J.S.) 12 refs.

Combustion characteristics and influential factors of isooctane active-thermal atmosphere combustion assisted by two-stage reaction of n-heptane

Energy Technology Data Exchange (ETDEWEB)

Lu, Xingcai; Ji, Libin; Ma, Junjun; Zhou, Xiaoxin; Huang, Zhen [Key Lab. for Power Machinery and Engineering of MOE, Shanghai Jiao Tong University, 200240 Shanghai (China)

2011-02-15

This paper presents an experimental study on the isooctane active-thermal atmosphere combustion (ATAC) which is assisted by two-stage reaction of n-heptane. The active-thermal atmosphere is created by low- and high-temperature reactions of n-heptane which is injected at intake port, and isooctane is directly injected into combustion chamber near the top dead center. The effects of isooctane injection timing, active-thermal atmosphere intensity, overall equivalence ratio, and premixed ratio on combustion characteristics and emissions are investigated. The experimental results reveal that, the isooctane ignition and combustion can be classified to thermal atmosphere combustion, active atmosphere combustion, and active-thermal atmosphere combustion respectively according to the extent of n-heptane oxidation as well as effects of isooctane quenching and charge cooling. n-Heptane equivalence ratio, isooctane equivalence ratio and isooctane delivery advance angle are major control parameters. In one combustion cycle, the isooctane ignited and burned after those of n-heptane, and then this combustion phenomenon can also be named as dual-fuel sequential combustion (DFSC). The ignition timing of the overall combustion event is mainly determined by n-heptane equivalence ratio and can be controlled in flexibility by simultaneously adjusting isooctane equivalence ratio. The isooctane ignition regime, overall thermal efficiency, and NO{sub x} emissions show strong sensitivity to the fuel delivery advance angle between 20 CA BTDC and 25 CA BTDC. (author)

Evaluation of self-combustion risk in tire derived aggregate fills.

Science.gov (United States)

Arroyo, Marcos; San Martin, Ignacio; Olivella, Sebastian; Saaltink, Maarten W

2011-01-01

Lightweight tire derived aggregate (TDA) fills are a proven recycling outlet for waste tires, requiring relatively low cost waste processing and being competitively priced against other lightweight fill alternatives. However its value has been marred as several TDA fills have self-combusted during the early applications of this technique. An empirical review of these cases led to prescriptive guidelines from the ASTM aimed at avoiding this problem. This approach has been successful in avoiding further incidents of self-combustion. However, at present there remains no rational method available to quantify self-combustion risk in TDA fills. This means that it is not clear which aspects of the ASTM guidelines are essential and which are accessory. This hinders the practical use of TDA fills despite their inherent advantages as lightweight fill. Here a quantitative approach to self-combustion risk evaluation is developed and illustrated with a parametric analysis of an embankment case. This is later particularized to model a reported field self-combustion case. The approach is based on the available experimental observations and incorporates well-tested methodological (ISO corrosion evaluation) and theoretical tools (finite element analysis of coupled heat and mass flow). The results obtained offer clear insights into the critical aspects of the problem, allowing already some meaningful recommendations for guideline revision. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mixture preparation and combustion in an optically-accessible HCCI, diesel engine; La preparation du melange et de la combustion dans un moteur Diesel, HCCI a acces optique

Energy Technology Data Exchange (ETDEWEB)

Kashdan, J.; Bruneaux, G. [Institut Francais du Petrole, 92 - Rueil-Malmaison (France)

2006-07-01

Planar laser-induced fluorescence (LIF) imaging techniques have been applied in order to study the mixture preparation and combustion process in a single cylinder, optically-accessible homogeneous charge, compression ignition (HCCI) engine. In particular, the influence of piston bowl geometry on the in-cylinder mixture distribution and subsequent combustion process has been investigated. A new optically-accessible piston design enabled the application of LIF diagnostics directly within the combustion chamber bowl. Firstly, laser-induced exciplex fluorescence (LIEF) was exploited in order to characterise the in-cylinder fuel spray and vapour distribution. Subsequently a detailed study of the two-stage HCCI combustion process was conducted by a combination of direct chemiluminescence imaging, laser-induced fluorescence (LIF) of the intermediate species formaldehyde (CH{sub 2}O) which is present during the cool flame and LIF of the OH radical which is subsequently present in the reaction and burned gas zones at higher temperature. Finally, spectrometry measurements were performed with the objective of determining the origin of the emitting species of the chemiluminescence signal. The experiments were performed on a single cylinder optical engine equipped with a direct-injection, common rail injection system and narrow angle injector. The experimental results presented reveal the significant role of the combustion chamber geometry on the mixture preparation and combustion characteristics for late HCCI injection strategies particularly in such cases where liquid impingement is unavoidable. Planar LIF 355 imaging revealed the presence of the intermediate species formaldehyde allowing the temporal and spatial detection of auto-ignition precursors prior to the signal observed by chemiluminescence in the early stages of the cool flame. Formaldehyde was then rapidly consumed at the start of main combustion which was marked not only by the increase in the main heat release

LES of explosions in venting chamber: A test case for premixed turbulent combustion models

OpenAIRE

Vermorel , Olivier; Quillatre , Pierre; Poinsot , Thierry

2017-01-01

International audience; This paper presents a new experimental and Large Eddy Simulation (LES) database to study upscaling effects in vented gas explosions. The propagation of premixed flames in three setups of increasing size is investigated experimentally and numerically. The baseline model is the well-known laboratory-scale combustion chamber from Sydney (Kent et al., 2005; Masri et al., 2012); two exact replicas at scales 6 and 24.4 were set up by GexCon (Bergen, Norway). The volume ratio...

Modeling and simulating combustion and generation of NOx

International Nuclear Information System (INIS)

Lazaroiu, Gheorghe

2007-01-01

This paper deals with the modeling and simulation of combustion processes and generation of NO x in a combustion chamber and boiler, with supplementary combustion in a gas turbine installation. The fuel burned in the combustion chamber was rich gas with a chemical composition more complex than natural gas. Pitcoal was used in the regenerative boiler. From the resulting combustion products, 17 compounds were retained, including nitrogen and sulphur compounds. Using the developed model, the simulation resulted in excess air for a temperature imposed at the combustion chamber exhaust. These simulations made it possible to determine the concentrations of combustion compounds with a variation in excess combustion. (author)

Coal-water slurry fuel internal combustion engine and method for operating same

Science.gov (United States)

McMillian, Michael H.

1992-01-01

An internal combustion engine fueled with a coal-water slurry is described. About 90 percent of the coal-water slurry charge utilized in the power cycle of the engine is directly injected into the main combustion chamber where it is ignited by a hot stream of combustion gases discharged from a pilot combustion chamber of a size less than about 10 percent of the total clearance volume of main combustion chamber with the piston at top dead center. The stream of hot combustion gases is provided by injecting less than about 10 percent of the total coal-water slurry charge into the pilot combustion chamber and using a portion of the air from the main combustion chamber that has been heated by the walls defining the pilot combustion chamber as the ignition source for the coal-water slurry injected into the pilot combustion chamber.

Experimental study on combustion and suppression characteristics of sodium fire in a columnar flow using extinguishing powder

International Nuclear Information System (INIS)

Huo Yan; Zhang Zhigang; Li Jinke; Liu Zhongkun; Ma Yaolong

2017-01-01

In the operation of the sodium-cooled fast reactor, the leakage and fire accident of liquid sodium is common and it is frequent in sodium-related facilities. This study focuses on the combustion and suppression characteristics of sodium fire in a columnar flow. Liquid sodium (250°C) is injected into a 7.9 m"3 cylindrical chamber at a flow rate of about 1.0 m"3/h to create a columnar sodium fire, and 18.4 kg class D extinguishing powder is sprayed after the liquid sodium injection. The temperature in the chamber space and sodium collection plate and the heat release rate from sodium fire are measured and analyzed. Based on the temperature data the sodium fire under suppression could be divided into four phases of dropping sharply, continuously remaining lower, rising and declining mildly, and depressing. The sodium fire in the space could be suppressed and cooled down if the extinguishing agent could spray in the early period of the liquid sodium injection. The extinguishing agent could suppress the combustion and spreading of liquid sodium dropping on the collection plate, limit the pool combustion area and postpone the commencement of sodium pool burning in spite of its later re-ignition happening. This study promises to evaluate the combustion and suppression characteristics of sodium fire in the sodium-related facilities. (author)

Improvement of Swirl Chamber Structure of Swirl-Chamber Diesel Engine Based on Flow Field Characteristics

Directory of Open Access Journals (Sweden)

Wenhua Yuan

2014-10-01

Full Text Available In order to improve combustion characteristic of swirl chamber diesel engine, a simulation model about a traditional cylindrical flat-bottom swirl chamber turbulent combustion diesel engine was established within the timeframe of the piston motion from the bottom dead centre (BDC to the top dead centre (TDC with the fluent dynamic mesh technique and flow field vector of gas in swirl chamber and cylinder; the pressure variation and temperature variation were obtained and a new type of swirl chamber structure was proposed. The results reveal that the piston will move from BDC; air in the cylinder is compressed into the swirl chamber by the piston to develop a swirl inside the chamber, with the ongoing of compression; the pressure and temperature are also rising gradually. Under this condition, the demand of diesel oil mixing and combusting will be better satisfied. Moreover, the new structure will no longer forma small fluid retention zone at the lower end outside the chamber and will be more beneficial to the mixing of fuel oil and air, which has presented a new idea and theoretical foundation for the design and optimization of swirl chamber structure and is thus of good significance of guiding in this regard.

KHD combustion chamber. Flexible use of alternative fuels in the cement plant; KHD Brennkammer. Flexibler Einsatz von alternativen Brennstoffen im Zementwerk

Energy Technology Data Exchange (ETDEWEB)

Schuermann, Heiko [Humboldt Wedag GmbH, Koeln (Germany)

2012-07-01

In many parts of the world, the use of alternative fuels is a recognized measure for reducing the CO{sub 2} emissions that result from burning primary fuels such as coal, oil and natural gas. Alternative or secondary fuels are the terms used for combustible residues from industrial and commercial manufacturing processes, agricultural production, and sorted municipal refuse. Due to the wide range of possible sources of alternative fuels, there is very great variation in their energy content, ash, moisture content, particle size, form, density etc., so there is no patent solution for their use in a cement plant. For proper operation of the rotary kiln, it is particularly important to use alternative fuel qualities that have good heat value and reactivity in order to achieve a stable, hot sintering zone and to completely burnout the highest possible amount of the fuel while it is suspended in the air stream. Combustion in the calciner places fewer demands on the properties of the alternative fuels than combustion in the rotary kiln burner does. This means that the calciner is the ideal combustion point for the usage of alternative fuels. To enable maximum possible flexibility for the combustion of widely differing alternative fuels in the calciner, KHD Humboldt Wedag offers the option of installing a combustion chamber in the modular PYROCLON calciner system. Due to the operating characteristics of this combustion chamber, which are described in the following sections of this article, even alternative fuels with low heat values and a low degree of preparation can be safely and completely burnt. (orig.)

Peltier-based cloud chamber

Science.gov (United States)

Nar, Sevda Yeliz; Cakir, Altan

2018-02-01

Particles produced by nuclear decay, cosmic radiation and reactions can be identified through various methods. One of these methods that has been effective in the last century is the cloud chamber. The chamber makes visible cosmic particles that we are exposed to radiation per second. Diffusion cloud chamber is a kind of cloud chamber that is cooled by dry ice. This traditional model has some application difficulties. In this work, Peltier-based cloud chamber cooled by thermoelectric modules is studied. The new model provided uniformly cooled base of the chamber, moreover, it has longer lifetime than the traditional chamber in terms of observation time. This gain has reduced the costs which spent each time for cosmic particle observation. The chamber is an easy-to-use system according to traditional diffusion cloud chamber. The new model is portable, easier to make, and can be used in the nuclear physics experiments. In addition, it would be very useful to observe Muons which are the direct evidence for Lorentz contraction and time expansion predicted by Einsteins special relativity principle.

Ignition system for an internal combustion engine with rotary system

Energy Technology Data Exchange (ETDEWEB)

Hochstein, P A

1977-05-18

In the Wankel engine, the sparking plugs spark three times per rotation of the rotor and are never cooled by the incoming mixture. This constant high temperature environment necessitates the use of special sparking plugs. The covered top of the sparking plug is particularly liable to carbon deposits. This invention makes it possible to use sparking plugs on the rotor, without the disadvantages due to the use of high voltage. Further, the use of distributors or mechanical devices determining the ignition timing is no longer necessary. The fuel/air mixture is ignited in a combustion chamber, which is limited by first and second components moving relative to one another in repeated cycles. A generator device is fitted to the first components and an ignition device to the second components. The magnetic flux linking takes place in a predetermined area of the relative movement between the first and second components in a repeated cycle. An ignition signal is produced in the combustion chamber by the magnetic flux linking.

Spray combustion of biomass-based renewable diesel fuel using multiple injection strategy in a constant volume combustion chamber

KAUST Repository

Jing, Wei

2016-05-26

Effect of a two-injection strategy associated with a pilot injection on the spray combustion process was investigated under conventional diesel combustion conditions (1000 K and 21% O2 concentration) for a biomass-based renewable diesel fuel, i.e., biomass to liquid (BTL), and a regular No. 2 diesel in a constant volume combustion chamber using multiband flame measurement and two-color pyrometry. The spray combustion flame structure was visualized by using multiband flame measurement to show features of soot formation, high temperature and low temperature reactions, which can be characterized by the narrow-band emissions of radicals or intermediate species such as OH, HCHO, and CH. The objective of this study was to identify the details of multiple injection combustion, including a pilot and a main injection, and to provide further insights on how the two injections interact. For comparison, three injection strategies were considered for both fuels including a two-injection strategy (Case TI), single injection strategy A (Case SA), and single injection strategy B (Case SB). Multiband flame results show a strong interaction, indicated by OH emissions between the pilot injection and the main injection for Case TI while very weak connection is found for the narrow-band emissions acquired through filters with centerlines of 430 nm and 470 nm. A faster flame development is found for the main injection of Case TI compared to Cases SA and SB, which could be due to the high temperature environment and large air entrainment from the pilot injection. A lower soot level is observed for the BTL flame compared to the diesel flame for all three injection types. Case TI has a lower soot level compared to Cases SA and SB for the BTL fuel, while the diesel fuel maintains a similar soot level among all three injection strategies. Soot temperature of Case TI is lower for both fuels, especially for diesel. Based on these results, it is expected that the two-injection strategy could be

Multi-objective optimization of cooling air distributions of grate cooler with different clinker particles diameters and air chambers by genetic algorithm

International Nuclear Information System (INIS)

Shao, Wei; Cui, Zheng; Cheng, Lin

2017-01-01

Highlights: • A multi-objective optimization model of air distributions of grate cooler by genetic algorithm is proposed. • Optimal air distributions of different conditions are obtained and validated by measurements. • The most economic average diameters of clinker particles is 0.02 m. • The most economic amount of air chambers is 9. - Abstract: The paper proposes a multi-objective optimization model of cooling air distributions of grate cooler in cement plant based on convective heat transfer principle and entropy generation minimization analysis. The heat transfer and flow models of clinker cooling process are brought out at first. Then the modified entropy generation numbers caused by heat transfer and viscous dissipation are considered as objective functions respectively which are optimized by genetic algorithm simultaneously. The design variables are superficial velocities of air chambers and thicknesses of clinker layer on different grate plates. The model is verified by a set of Pareto optimal solutions and scattered distributions of design variables. Sensitive analysis of average diameters of clinker particles and amount of air chambers are carried out based on the optimization model. The optimal cooling air distributions are compared by heat recovered, energy consumption of cooling fans and heat efficiency of grate cooler. And all of them are selected from the Pareto optimal solutions based on energy consumption of cooling fans minimization. The results show that the most effective and economic average diameter of clinker particles is 0.02 m and the amount of air chambers is 9.

Thermodynamic evaluation of chemical looping combustion for combined cooling heating and power production driven by coal

International Nuclear Information System (INIS)

Fan, Junming; Hong, Hui; Zhu, Lin; Wang, Zefeng; Jin, Hongguang

2017-01-01

Highlights: • An ex-situ coal gasification chemical looping combustion integrated with CCHP process has been presented. • This novel process maintains a maximum energy efficiency of 60.34%. • The fossil energy saving ratio of this process is optimize to be 27.20%. - Abstract: This study carries out an investigation concerning on the benefits of ex-situ coal gasification chemical looping combustion integrated with combined cooling, heating and power generation (CCHP-CLC) by means of thermodynamic evaluation. The coal gasification syngas is introduced into chemical looping combustion for inherent separation of CO_2 without extra energy consumed. The combustion flue gases from both air reactor and fuel reactor are sequentially fed into gas turbines for electricity production, a heat recovery vapor generator unit for further electricity generation with driving a LiBr-H_2O absorption chiller for cooling production in summer and finally a heat exchanger for daily heat water production. A preliminary parameter analysis helps to obtain the optimum operating condition, as steam-to-coal ratio (S/C) of 0.05, oxygen-to-coal ratio (O/C) of 0.75, and operating pressure of chemical looping combustion process of 5 bar. The overall energy efficiency of the CCHP-CLC process is calculated equal to 58.20% in summer compared with that of 60.34% in winter. Importantly, by utilization of such process, the reduction potential of fossil fuel (coal) consumption has been demonstrated to be 23.36% in summer and 27.20% in winter.

Comparison of soot formation for diesel and jet-a in a constant volume combustion chamber using two-color pyrometry

KAUST Repository

Jing, Wei; Roberts, William L.; Fang, Tiegang

2014-01-01

The measurement of the two-color line of sight soot and KL factor for NO.2 diesel and jet-A fuels was conducted in an optical constant volume combustion chamber by using a high speed camera under 1000 K ambient temperature and varied oxygen

Experimental and analytical study on thermoelectric self cooling of devices

International Nuclear Information System (INIS)

Martinez, A.; Astrain, D.; Rodriguez, A.

2011-01-01

This paper presents and studies the novel concept of thermoelectric self cooling, which can be introduced as the cooling and temperature control of a device using thermoelectric technology without electricity consumption. For this study, it is designed a device endowed with an internal heat source. Subsequently, a commonly used cooling system is attached to the device and the thermal performance is statistically assessed. Afterwards, it is developed and studied a thermoelectric self cooling system appropriate for the device. Experimental and analytical results show that the thermal resistance between the heat source and the environment reduced by 25-30% when the thermoelectric self cooling system is installed, and indicates the promising applicability of this technology to devices that generate large amounts of heat, such as electrical power converters, transformers and control systems. Likewise, it was statistically proved that the thermoelectric self cooling system leads to significant reductions in the temperature difference between the heat source and the environment, and, what is more, this reduction increases as the heat flow generated by the heat source increases, which makes evident the fact that thermoelectric self cooling systems work as temperature controllers. -- Highlights: → Novel concept of thermoelectric self cooling is presented and studied. → No extra electricity is needed. → Thermal resistance between the heat source and the environment reduces by 25-30%. → Increasing reduction in temperature difference between heat source and environment. → Great applicability to any device that generates heat and must be cooled.

CFD analysis of combustion of natural gas and syngas from biomass pyrolysis in the combustion chamber of a micro gas turbine

Energy Technology Data Exchange (ETDEWEB)

Fantozzi, Francesco; Laranci, Paolo; D' Alessandro, Bruno [University of Perugia (DII/UNIPG) (Italy). Dept. of Industrial Engineering], Emails: fanto@unipg.it, paolo.laranci@unipg.it, dalessandro@bio-net.it

2009-07-01

Micro gas turbines (MGT) can be profitably used for the production of distributed energy (DE), with the possibility to use gaseous fuels with low BTU derived from biomass or waste through the pyrolysis or gasification processes. These synthesis gases (SG) show significant differences with respect to natural gas (NG), in terms of composition, calorific value, content of hydrogen, tar and particulate matter content; such differences can be turn into problems of ignition, instability burning, difficulties in controlling the emissions and fouling. CFD analysis of the combustion process is an essential tool for identifying the main critical arising in using these gases, in order to modify existing geometries and to develop new generation of combustor for use with low BTU gases. This paper describes the activities of experimental and numerical analysis carried out to study the combustion process occurring inside an existing annular Rich-Quench-Lean (RQL) Combustion Chamber (CC) of a 80 kW MGT. In the paper some results of a CFD study of the combustion process performed with an original developed chemical models are reported in terms of temperature and velocity distributions inside the CC and in terms of compositions of turbine inlet gas and of its thermodynamic parameters (mass flow, temperature, pressure). An evaluation of pollutant emissions of CO, CO{sub 2} and NOx and a comparison with the available experimental data relating to the case of combustion of NG is also provided in the paper. Moreover, the carried out investigation concerns the case of operation with a SG fuel derived from biomass in an Integrated Pyrolysis Regenerated Plant (IPRP). (author)

Gas turbine structural mounting arrangement between combustion gas duct annular chamber and turbine vane carrier

Science.gov (United States)

Wiebe, David J.; Charron, Richard C.; Morrison, Jay A.

2016-10-18

A gas turbine engine ducting arrangement (10), including: an annular chamber (14) configured to receive a plurality of discrete flows of combustion gases originating in respective can combustors and to deliver the discrete flows to a turbine inlet annulus, wherein the annular chamber includes an inner diameter (52) and an outer diameter (60); an outer diameter mounting arrangement (34) configured to permit relative radial movement and to prevent relative axial and circumferential movement between the outer diameter and a turbine vane carrier (20); and an inner diameter mounting arrangement (36) including a bracket (64) secured to the turbine vane carrier, wherein the bracket is configured to permit the inner diameter to move radially with the outer diameter and prevent axial deflection of the inner diameter with respect to the outer diameter.

Pulsating combustion - Combustion characteristics and reduction of emissions

Energy Technology Data Exchange (ETDEWEB)

Lindholm, Annika

1999-11-01

In the search for high efficiency combustion systems pulsating combustion has been identified as one of the technologies that potentially can meet the objectives of clean combustion and good fuel economy. Pulsating combustion offers low emissions of pollutants, high heat transfer and efficient combustion. Although it is an old technology, the interest in pulsating combustion has been renewed in recent years, due to its unique features. Various applications of pulsating combustion can be found, mainly as drying and heating devices, of which the latter also have had commercial success. It is, however, in the design process of a pulse combustor, difficult to predict the operating frequency, the heat release etc., due to the lack of a well founded theory of the phenomenon. Research concerning control over the combustion process is essential for developing high efficiency pulse combustors with low emissions. Natural gas fired Helmholtz type pulse combustors have been the experimental objects of this study. In order to investigate the interaction between the fluid dynamics and the chemistry in pulse combustors, laser based measuring techniques as well as other conventional measuring techniques have been used. The experimental results shows the possibilities to control the combustion characteristics of pulsating combustion. It is shown that the time scales in the large vortices created at the inlet to the combustion chamber are very important for the operation of the pulse combustor. By increasing/decreasing the time scale for the large scale mixing the timing of the heat release is changed and the operating characteristics of the pulse combustor changes. Three different means for NO{sub x} reduction in Helmholtz type pulse combustors have been investigated. These include exhaust gas recirculation, alteration of air/fuel ratio and changed inlet geometry in the combustion chamber. All used methods achieved less than 10 ppm NO{sub x} emitted (referred to stoichiometric

Fuel spray and combustion characteristics of butanol blends in a constant volume combustion chamber

International Nuclear Information System (INIS)

Liu, Yu; Li, Jun; Jin, Chao

2015-01-01

Highlights: • A sudden drop is observed in spray penetration for B10S10D80 fuel at 800 and 900 K. • With increasing of temperature, auto-ignition timings of fuels become unperceivable. • Low n-butanol addition has little effect on autoignition timings from 800 to 1200 K. • n-Butanol additive can reduce soot emissions at the near-wall regions. • Larger soot reduction is seen at higher ambient temperatures for n-butanol addition. - Abstract: The processes of spray penetrations, flame propagation and soot formation and oxidation fueling n-butanol/biodiesel/diesel blends were experimentally investigated in a constant volume combustion chamber with an optical access. B0S20D80 (0% n-butanol, 20% soybean biodiesel, and 80% diesel in volume) was prepared as the base fuel. n-Butanol was added into the base fuel by volumetric percent of 5% and 10%, denoted as B5S15D80 (5% n-butanol/15% soybean biodiesel/80% diesel) and B10S10D80 (10% n-butanol/10% soybean biodiesel/80% diesel). The ambient temperatures at the time of fuel injection were set to 800 K, 900 K, 1000 K, and 1200 K. Results indicate that the penetration length reduces with the increase of n-butanol volumes in blending fuels and ambient temperatures. The spray penetration presents a sudden drop as fueling B10S10D80 at 800 K and 900 K, which might be caused by micro-explosion. A larger premixed combustion process is observed at low ambient temperatures, while the heat release rate of high ambient temperatures presents mixing controlled diffusion combustion. With a lower ambient temperature, the auto-ignition delay becomes longer with increasing of n-butanol volume in blends. However, with increasing of ambient temperatures, the auto-ignition timing between three fuels becomes unperceivable. Generally, low n-butanol addition has a limited or no effect on the auto-ignition timing in the current conditions. Compared with the base fuel of B0S20D80, n-butanol additive with 5% or 10% in volume can reduce soot

One-dimensional flame instability and control of burning in fire-chamber

Directory of Open Access Journals (Sweden)

Victor E. Volkov

2015-03-01

Full Text Available The flame stability with regard to one-dimensional exponential perturbations both for the combustion in the fire-chamber and the flame propagating in closed tubes or chambers is investigated. It is proved that both stability and instability are possible for the combustion process. At the same time the one-dimensional flame instability is guaranteed near the front wall of the fire-chamber where the fuel supply is realized. Therefore the control of combustion in the fire-chamber leads to support of the flame at the maximum possible distance from the front wall of the fire-chamber to prevent the vibratory combustion or to diminish intensity of pulsations if these pulsations are inevitable.

Variation of diesel soot characteristics by different types and blends of biodiesel in a laboratory combustion chamber

Energy Technology Data Exchange (ETDEWEB)

Omidvarborna, Hamid; Kumar, Ashok [Department of Civil Engineering, The University of Toledo, Toledo, OH (United States); Kim, Dong-Shik, E-mail: dong.kim@utoledo.edu [Department of Chemical and Environmental Engineering, The University of Toledo, Toledo, OH (United States)

2016-02-15

Very little information is available on the physical and chemical properties of soot particles produced in the combustion of different types and blends of biodiesel fuels. A variety of feedstock can be used to produce biodiesel, and it is necessary to better understand the effects of feedstock-specific characteristics on soot particle emissions. Characteristics of soot particles, collected from a laboratory combustion chamber, are investigated from the blends of ultra-low sulfur diesel (ULSD) and biodiesel with various proportions. Biodiesel samples were derived from three different feedstocks, soybean methyl ester (SME), tallow oil (TO), and waste cooking oil (WCO). Experimental results showed a significant reduction in soot particle emissions when using biodiesel compared with ULSD. For the pure biodiesel, no soot particles were observed from the combustion regardless of their feedstock origins. The overall morphology of soot particles showed that the average diameter of ULSD soot particles is greater than the average soot particles from the biodiesel blends. Transmission electron microscopy (TEM) images of oxidized soot particles are presented to investigate how the addition of biodiesel fuels may affect structures of soot particles. In addition, inductively coupled plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were conducted for characterization of soot particles. Unsaturated methyl esters and high oxygen content of biodiesel are thought to be the major factors that help reduce the formation of soot particles in a laboratory combustion chamber. - Highlights: • The unsaturation of biodiesel fuel was correlated with soot characteristics. • Average diameters of biodiesel soot were smaller than that of ULSD. • Eight elements were detected as the marker metals in biodiesel soot particles. • As the degree of unsaturation increased, the oxygen content in FAMEs increased. • Biodiesel

Combustion driven NF3 chemical laser

International Nuclear Information System (INIS)

1975-01-01

Stable, inert, non-corrosive nitrogen trifluoride gas and an inorganic source of hydrogen or deuterium gas are used as reactants in a compact combustion driven chemical laser. Nitrogen trifluoride is introduced into the combustion chamber of a chemical laser together with a hydrogen source selected from hydrogen, hydrazine, ammonia, acetylene, or benzene and the deuterated isotopes thereof and an optional inert diluent gas wherein the nitrogen trifluoride and the hydrogen- or deuterium-source gas hypergolically reacted upon heating to initiation temperature. Dissociated products from the reaction pass into a laser cavity at supersonic velocities where they are reacted with a source gas which is the isotopic opposite of the gas introduced into the combustor and which has been heated by regenerative cooling. Excited molecules of hydrogen fluoride or deuterium fluoride produce laser radiation which leaves the optical resonator cavity transversely to the flow of gases

Self pumping magnetic cooling

International Nuclear Information System (INIS)

Chaudhary, V; Wang, Z; Ray, A; Ramanujan, R V; Sridhar, I

2017-01-01

Efficient thermal management and heat recovery devices are of high technological significance for innovative energy conservation solutions. We describe a study of a self-pumping magnetic cooling device, which does not require external energy input, employing Mn–Zn ferrite nanoparticles suspended in water. The device performance depends strongly on magnetic field strength, nanoparticle content in the fluid and heat load temperature. Cooling (Δ T ) by ∼20 °C and ∼28 °C was achieved by the application of 0.3 T magnetic field when the initial temperature of the heat load was 64 °C and 87 °C, respectively. These experiments results were in good agreement with simulations performed with COMSOL Multiphysics. Our system is a self-regulating device; as the heat load increases, the magnetization of the ferrofluid decreases; leading to an increase in the fluid velocity and consequently, faster heat transfer from the heat source to the heat sink. (letter)

Hot-gas-side heat transfer characteristics of subscale, plug-nozzle rocket calorimeter chamber

Science.gov (United States)

Quentmeyer, Richard J.; Roncace, Elizabeth A.

1993-01-01

An experimental investigation was conducted to determine the hot-gas-side heat transfer characteristics for a liquid-hydrogen-cooled, subscale, plug-nozzle rocket test apparatus. This apparatus has been used since 1975 to evaluate rocket engine advanced cooling concepts and fabrication techniques, to screen candidate combustion chamber liner materials, and to provide data for model development. In order to obtain the data, a water-cooled calorimeter chamber having the same geometric configuration as the plug-nozzle test apparatus was tested. It also used the same two showerhead injector types that were used on the test apparatus: one having a Rigimesh faceplate and the other having a platelet faceplate. The tests were conducted using liquid oxygen and gaseous hydrogen as the propellants over a mixture ratio range of 5.8 to 6.3 at a nominal chamber pressure of 4.14 MPa abs (600 psia). The two injectors showed similar performance characteristics with the Rigimesh faceplate having a slightly higher average characteristic-exhaust-velocity efficiency of 96 percent versus 94.4 percent for the platelet faceplate. The throat heat flux was 54 MW/m(sup 2) (33 Btu/in.(sup 2)-sec) at the nominal operating condition, which was a chamber pressure of 4.14 MPa abs (600 psia), a hot-gas-side wall temperature of 730 K (1314 R), and a mixture ratio of 6.0. The chamber throat region correlation coefficient C(sub g) for a Nusselt number correlation of the form Nu =C(sub g)Re(sup 0.8)Pr(sup 0.3) averaged 0.023 for the Rigimesh faceplate and 0.026 for the platelet faceplate.

Development and application of a high-temperature sampling probe for burning chamber conditions of fluidized-bed combustion; Korkean laempoetilan naeytteenottosondin kehittaeminen ja soveltaminen leijukerrospolton tulipesaeolosuhteisiin

Energy Technology Data Exchange (ETDEWEB)

Larjava, K.; Paerkkae, M.; Jormanainen, P.; Roine, J.; Paakkinen, K. [VTT Chemistry, Espoo (Finland); Linna, V. [VTT Energy, Jyvaeskylae (Finland)

1996-12-01

A sampling probe for the burning chamber conditions of fluidized-bed combustion will be developed in this project. The probe will be suitable for sampling vaporous heavy and alkali metals and other condensing compounds (e.g. chlorides) as well combustion gases and alternatively also flue gas particles at high temperatures. The knowledge gained with the probe will help understanding, developing and modeling combustion processes and will thus aid the manufacturers of the boilers. (author)

Experimental investigation of biomimetic self-pumping and self-adaptive transpiration cooling.

Science.gov (United States)

Jiang, Pei-Xue; Huang, Gan; Zhu, Yinhai; Xu, Ruina; Liao, Zhiyuan; Lu, Taojie

2017-09-01

Transpiration cooling is an effective way to protect high heat flux walls. However, the pumps for the transpiration cooling system make the system more complex and increase the load, which is a huge challenge for practical applications. A biomimetic self-pumping transpiration cooling system was developed inspired by the process of trees transpiration that has no pumps. An experimental investigation showed that the water coolant automatically flowed from the water tank to the hot surface with a height difference of 80 mm without any pumps. A self-adaptive transpiration cooling system was then developed based on this mechanism. The system effectively cooled the hot surface with the surface temperature kept to about 373 K when the heating flame temperature was 1639 K and the heat flux was about 0.42 MW m -2 . The cooling efficiency reached 94.5%. The coolant mass flow rate adaptively increased with increasing flame heat flux from 0.24 MW m -2 to 0.42 MW m -2 while the cooled surface temperature stayed around 373 K. Schlieren pictures showed a protective steam layer on the hot surface which blocked the flame heat flux to the hot surface. The protective steam layer thickness also increased with increasing heat flux.

Fuel Combustion Laboratory | Transportation Research | NREL

Science.gov (United States)

Fuel Combustion Laboratory Fuel Combustion Laboratory NREL's Fuel Combustion Laboratory focuses on designs, using both today's technology and future advanced combustion concepts. This lab supports the combustion chamber platform for fuel ignition kinetics research, was acquired to expand the lab's

High Temperature Fission Chamber for He- and FLiBe-cooled Reactors

Energy Technology Data Exchange (ETDEWEB)

Bell, Zane W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giuliano, Dominic R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holcomb, David Eugene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lance, Michael J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, Roger G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Warmack, Robert J. Bruce [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wilson, Dane F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Mark J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-01-01

We have evaluated candidate technologies for in-core fission chambers for high-temperature reactors to monitor power level via measurements of neutron flux from start-up through full power at up to 800°C. This research is important because there are no commercially available instruments capable of operating above 550 °C. Component materials and processes were investigated for fission chambers suitable for operation at 800 °C in reactors cooled by molten fluoride salt (FLiBe) or flowing He, with an emphasis placed on sensitivity (≥ 1 cps/nv), service lifetime (2 years at full power), and resistance to direct immersion in FLiBe. The latter gives the instrument the ability to survive accidents involving breach of a thimble. The device is envisioned to be a two-gap, three-electrode instrument constructed from concentric nickel-plated alumina cylinders and using a noble gas–nitrogen fill-gas. We report the results of measurements and calculations of the response of fill gasses, impurity migration in nickel alloy, brazing of the alumina insulator, and thermodynamic calculations.

Environmental effects of using Methanol as a biofuel into the combustion chamber of a heavy-duty diesel engine

Directory of Open Access Journals (Sweden)

kianoosh shojae

2016-12-01

Full Text Available Methanol as a biofuel is an environmentally friendly substitute for pure diesel and can be obtained from biomasses. The use of biofuels such as methanol for the combustion process is associated with positive impacts on the environment. Using pure methanol or a blend of diesel/methanol fuel in motorized vehicles has been proposed by researchers. In this paper, pure methanol was injected into the combustion chamber of a ISM 370 HD diesel engine and the exhaust emissions were evaluated by using AVL FIRE CFD code software at four engine speeds (1200, 1400, 1600 and 1800 rpm. Additionally, the influences of EGR mass fraction and various injection timings were investigated. In order to validate the simulation results, in-cylinder mean pressure and rate of heat release (RHR were compared with experimental data, and the results gave an acceptable agreement. The obtained results from the conducted simulation showed that the use of methanol fuel in the combustion chamber dramatically reduced the amount of exhaust emissions such as NO, soot, CO, and CO2 to 90%, 75%, 40%, and 26%, respectively. In addition, a mass fraction of EGR (20% caused a reduction in the amount of exhaust NO to about 12%. It was determined that when a system is equipped with a fueling system at 3 deg before top dead center (BTDC, the exhaust NO and soot are reduced by 5.8% and 3%.

An Assessment on Temperature Profile of Jet-A/Biodiesel Mixture in a Simple Combustion Chamber with Plain Orifice Atomiser

Science.gov (United States)

Ng, W. X.; Mazlan, N. M.; Ismail, M. A.; Rajendran, P.

2018-05-01

The preliminary study to evaluate influence of biodiesel/kerosene mixtures on combustion temperature profile is explored. A simple cylindrical combustion chamber configuration with plain orifice atomiser is used for the evaluation. The evaluation is performed under stoichiometric air to fuel ratio. Six samples of fuels are used: 100BD (pure biodiesel), 100KE (pure Jet-A), 20KE80BD (20% Jet-A/80% Biodiesel), 40KE60BD (40% Jet-A/60% Biodiesel), 60KE40BD (60% Jet-A/40% Biodiesel), and 80KE20BD (80% Jet-A/20% Biodiesel). Results showed that the oxygen content, viscosity, and lower heating value are key parameters in affecting the temperature profile inside the chamber. Biodiesel is known to have higher energy content, higher viscosity and lower heating value compared to kerosene. Mixing biodiesel with kerosene improves viscosity and caloric value but reduces oxygen content of the fuel. High oxygen content of the biodiesel resulted to the highest flame temperature. However the flame temperature reduce as the percentage of biodiesel in the fuel mixture reduces.

New Metamaterials with Combined Subnano - and Mesoscale Topology for High-efficiency Catalytic Combustion Chambers of Innovative Gas Turbine Engines

Science.gov (United States)

Knysh, Yu A.; Xanthopoulou, G. G.

2018-01-01

The object of the study is a catalytic combustion chamber that provides a highly efficient combustion process through the use of effects: heat recovery from combustion, microvortex heat transfer, catalytic reaction and acoustic resonance. High efficiency is provided by a complex of related technologies: technologies for combustion products heat transfer (recuperation) to initial mixture, catalytic processes technology, technology for calculating effective combustion processes based on microvortex matrices, technology for designing metamaterials structures and technology for obtaining the required topology product by laser fusion of metal powder compositions. The mesoscale level structure provides combustion process with the use of a microvortex effect with a high intensity of heat and mass transfer. High surface area (extremely high area-to-volume ratio) created due to nanoscale periodic structure and ensures catalytic reactions efficiency. Produced metamaterial is the first multiscale product of new concept which due to combination of different scale level periodic topologies provides qualitatively new set of product properties. This research is aimed at solving simultaneously two global problems of the present: ensure environmental safety of transport systems and power industry, as well as the economy and rational use of energy resources, providing humanity with energy now and in the foreseeable future.

Numerical investigation of unsteady detonation waves in combustion chamber using Shchelkin spirals

Directory of Open Access Journals (Sweden)

Repaka Ramesh

2016-09-01

Full Text Available : Pulse Detonation Engine (PDE is considered to be a propulsive system of future air vehicles. The main objective is to minimizing the Deflagration to Detonation transition run-up distance and time by placing Shchelkin spiral with varying pitch length. Here we have considered blockage-area ratio is 0.5 as optimal value from review of previous studies. In the present study the detonation initiation and propagation is modeled numerically using commercial CFD codes GAMBIT and FLUENT. The unsteady and two-dimensional compressible Reynolds Averaged Navier-Stokes equation is used to simulate the model. Fuel-air mixture of Hydrogen-air is used for better efficiency of PDE. It is very simple straight tube with Shchelkin spirals, one of the methods which is used to initiate detonation is creation of high pressure and temperature chamber region with 0.5cm from closed end of tube where shock will generate and transition into low pressure and temperature region propagates towards end of the tube. Two different zones namely high and low pressure zones are used as interface in modeling and patching has been used to fill the zones with hydrogen and oxygen with different pressure and temperatures hence shock leads to propagate inside the combustion chamber.

Simulation and analysis of the tangential flow in the combustion chamber of a steam generator; Simulacion y analisis del flujo tangencial en la camara de combustion de un generador de vapor

Energy Technology Data Exchange (ETDEWEB)

Hernandez Ramirez, Isaias

1997-06-01

The present thesis work describes the simulation and analysis of the combustion chamber of a steam generator VU-60 of the tangential type, which is based on the solution of the generalized equation of transport, using mathematical models developed for the characterization of physical phenomena to close the governing equations systems. For the solution of the mathematical models and governing equations the method of finite volume was used, which is based on the concept of control volume. A three-dimensional computational model was developed by means of which the velocity, pressure, and temperature profiles were considered and species in steady state in time for the combustion chamber and fuel supplying ducts for an existing design of a steam generator. The model provides information related to the behavior of the connected variables and that are of interest in the design and manufacture of steam generators of the tangential type. Turbulence and combustion models were used for the estimation of the velocity and pressure profiles for the case of the equation of momentum and temperature for the case of the energy equation. The radiation model was not connected to the system of governing equations due to limitations in the memory of the computer used for the simulation of these phenomena. The computational model was developed in a workstation Risc System/6000 and by means of the Code of computational dynamics of fluids Star-CD. 5390 cells and 43350 vertexes constitute the model. With this model information is generated to support the designer of the steam generators in the decision making during the design and the manufacture of the combustion chambers of the steam generators of high performance of the tangential type similar to the one analyzed in this thesis work. The results obtained of the present thesis are: The flow patterns of the combustion gases inside the combustion chamber of the steam generator, as well as the velocity profiles of the oxidant in the

PREMIXED FLAME PROPAGATION AND MORPHOLOGY IN A CONSTANT VOLUME COMBUSTION CHAMBER

Energy Technology Data Exchange (ETDEWEB)

Hariharan, A; Wichman, IS

2014-06-04

This work presents an experimental and numerical investigation of premixed flame propagation in a constant volume rectangular channel with an aspect ratio of six (6) that serves as a combustion chamber. Ignition is followed by an accelerating cusped finger-shaped flame-front. A deceleration of the flame is followed by the formation of a "tulip"-shaped flame-front. Eventually, the flame is extinguished when it collides with the cold wall on the opposite channel end. Numerical computations are performed to understand the influence of pressure waves, instabilities, and flow field effects causing changes to the flame structure and morphology. The transient 2D numerical simulation results are compared with transient 3D experimental results. Issues discussed are the appearance of oscillatory motions along the flame front and the influences of gravity on flame structure. An explanation is provided for the formation of the "tulip" shape of the premixed flame front.

Self-cooled liquid-metal blanket concept

International Nuclear Information System (INIS)

Malang, S.; Arheidt, K.; Barleon, L.

1988-01-01

A blanket concept for the Next European Torus (NET) where 83Pb-17Li serves both as breeder material and as coolant is described. The concept is based on the use of novel flow channel inserts for a decisive reduction of the magnetohydrodynamic (MHD) pressure drop and employs beryllium as neutron multiplier in order to avoid the need for breeding blankets at the inboard side of the torus. This study includes the design, neutronics, thermal hydraulics, stresses, MHDs, corrosion, tritium recovery, and safety of a self-cooled liquid-metal blanket. The results of the investigations indicate that the self-cooled blanket is an attractive alternative to other driver blanket concepts for NET and that it can be extrapolated to the conditions of a DEMO reactor

High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers

NARCIS (Netherlands)

Sliphorst, M.

2011-01-01

Ever since the early stages of space transportation in the 1940’s, and the related liquid propellant rocket engine development, combustion instability has been a major issue. High frequency combustion instability (HFCI) is the interaction between combustion and the acoustic field in the combustion

Modelling auto ignition of hydrogen in a jet ignition pre-chamber

Energy Technology Data Exchange (ETDEWEB)

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

2010-04-15

Spark-less jet ignition pre-chambers are enablers of high efficiencies and load control by quantity of fuel injected when coupled with direct injection of main chamber fuel, thus permitting always lean burn bulk stratified combustion. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the pre-chamber, where it mixes with the air entering from the main chamber. Combustion of the air and fuel mixture then starts within the pre-chamber because of the high temperature of the hot glow plug, and then jets of partially combusted hot gases enter the main chamber igniting there in the bulk, over multiple ignition points, lean stratified mixtures of air and fuel. The paper describes the operation of the spark-less jet ignition pre-chamber coupling CFD and CAE engine simulations to allow component selection and engine performance evaluation. (author)

The atomization and burning of biofuels in the combustion chambers of gas turbine engines

Science.gov (United States)

Maiorova, A. I.; Vasil'ev, A. Yu; Sviridenkov, A. A.; Chelebyan, O. G.

2017-11-01

The present work analyzes the effect of physical properties of liquid fuels with high viscosity (including biofuels) on the spray and burning characteristics. The study showed that the spray characteristics behind devices well atomized fuel oil, may significantly deteriorate when using biofuels, until the collapse of the fuel bubble. To avoid this phenomenon it is necessary to carry out the calculation of the fuel film form when designing the nozzles. As a result of this calculation boundary curves in the coordinates of the Reynolds number on fuel - the Laplace number are built, characterizing the transition from sheet breakup to spraying. It is shown that these curves are described by a power function with the same exponent for nozzles of various designs. The swirl of air surrounding the nozzle in the same direction, as the swirl of fuel film, can significantly improve the performance of atomization of highly viscous fuel. Moreover the value of the tangential air velocity has the determining influence on the film shape. For carrying out of hot tests in aviation combustor some embodiments of liquid fuels were proved and the most preferred one was chosen. Fire tests of combustion chamber compartment at conventional fuel has shown comprehensible characteristics, in particular wide side-altars of the stable combustion. The blended biofuel application makes worse combustion stability in comparison with kerosene. A number of measures was recommended to modernize the conventional combustors when using biofuels in gas turbine engines.

Development of a cooling system and vacuum chamber for the pion tracker for HADES

Energy Technology Data Exchange (ETDEWEB)

Schmitt, Tobias [TU Muenchen, James-Franck-Strasse, D-85748 Garching (Germany); Collaboration: HADES-Collaboration

2014-07-01

One of the future experiments planned at SIS18 with the HADES spectrometer in GSI Darmstadt envisages the employment of a pion beam colliding on a LH2 or a nuclear target. Due to the fact that the secondary pion beam has a high momentum spread, the momentum for each individual pion has to be measured for the planned exclusive measurements. For this purpose our group develops a pion tracking system, consisting of two double sided striped silicon detectors. Both will be located at different positions in the beamline in front of the HADES experiment, therefore they have to deal with high particle rates. Considering the detection of pions (MIPs), the noise of the detectors has to have a very small level. This can be achieved by cooling. For now the final version of the detector chamber and cooling system has been built and is currently tested. The proposed poster shows the current status and performance of the cooling system for the silicon detector, focusing on the reduction of the leakage current and the noise.

Cocaine self-administration in social dyads using custom-built operant conditioning chambers.

Science.gov (United States)

Lacy, Ryan T; Strickland, Justin C; Smith, Mark A

2014-10-30

Traditionally, the analysis of intravenous drug self-administration is limited to conditions in which subjects are tested in isolation. This limits the translational appeal of these studies because drug use in humans often occurs in the presence of others. We used custom-built operant conditioning chambers that allowed social dyads visual, olfactory, auditory, and limited tactile contact while concurrently self-administering cocaine. Male rats were trained to respond according to a fixed interval schedule of reinforcement (with a limited hold) in order to determine if patterns of cocaine (0.75mg/kg/infusion) self-administration became more similar over time in social pairs. Cocaine self-administration was tested across five days according to a 10-min fixed interval schedule (with a 5-min limited hold). Quarter-life values (time at which 25% of responses were emitted per interval) were analyzed using intraclass correlations. The total number of reinforcers obtained did not vary across the five days of testing; however, quarter-life values became progressively more similar between individuals within the social dyads. Standard operant conditioning chambers are unable to assess responding in multiple animals due to their small size, the need to prevent subjects from responding on the lever of their partner, and the need to prevent infusion lines from entangling. By using custom-built social operant conditioning chambers, we assessed the effects of social contact on cocaine self-administration. Social operant conditioning chambers can be used as a preclinical method to examine social influences on drug self-administration under conditions that approximate human substance use. Copyright © 2014 Elsevier B.V. All rights reserved.

A practical approach to estimate emission rates of indoor air pollutants due to the use of personal combustible products based on small-chamber studies.

Science.gov (United States)

Szulejko, Jan E; Kim, Ki-Hyun

2016-02-01

As emission rates of airborne pollutants are commonly measured from combusting substances placed inside small chambers, those values need to be re-evaluated for the possible significance under practical conditions. Here, a simple numerical procedure is investigated to extrapolate the chamber-based emission rates of formaldehyde that can be released from various combustible sources including e-cigarettes, conventional cigarettes, or scented candles to their concentration levels in a small room with relatively poor ventilation. This simple procedure relies on a mass balance approach by considering the masses of pollutants emitted from source and lost through ventilation under the assumption that mixing occurs instantaneously in the room without chemical reactions or surface sorption. The results of our study provide valuable insights into re-evaluation procedure of chamber data to allow comparison between extrapolated and recommended values to judge the safe use of various combustible products in confined spaces. If two scented candles with a formaldehyde emission rate of 310 µg h(-1) each were lit for 4 h in a small 20 m(3) room with an air change rate of 0.5 h(-1), then the 4-h (candle lit) and 8-h (up to 8 h after candle lighting) TWA [FA] were determined to be 28.5 and 23.5 ppb, respectively. This is clearly above the 8-h NIOSH recommended exposure limit (REL) time weighted average of 16 ppb. Copyright © 2015 Elsevier Ltd. All rights reserved.

Process gas generator feeding internal combustion piston engines

Energy Technology Data Exchange (ETDEWEB)

Iwantscheff, G; Kostka, H; Henkel, H J

1978-10-26

The invention relates to a process gas generator feeding gaseous fuel to internal combustion piston engines. The cylinder linings of the internal combustion engine are enclosed by the catalytic reaction chamber of the process gas generator which contains perforated sintered nozzle bricks as carriers of the catalysts needed for the conversion. The reaction chamber is surrounded by the exhaust gas chamber around which a tube coil is ound which feeds the fuel charge to the reaction chamber after evaporation and mixing with exhaust gas and air. The fuel which may be used for this purpose, e.g., is low-octane gasoline or diesel fuel. In the reaction chamber the fuel is catalytically converted at temperatures above 200/sup 0/C, e.g., into low-molecular paraffins, carbon monoxide and hydrogen. Operation of the internal combustion engine with a process gas generator greatly reduces the pollutant content of the exhaust gases.

Development and application of a high-temperature sampling probe for burning chamber conditions in fluidized-bed combustion; Korkean laempoetilan naeytteenottosondin kehittaeminen ja soveltaminen leijukerrospolton tulipesaeolosuhteisiin

Energy Technology Data Exchange (ETDEWEB)

Larjava, K.; Paerkkae, M. [VTT Chemical Technology, Espoo (Finland); Linna, V. [VTT Energy, Jyvaeskylae (Finland). Environmental Technology

1997-10-01

Determination of heavy and alkali metals and other condensing compounds (e.g. chlorides) in combustion chamber conditions is limited by the poor suitability of traditional methods for sampling at high temperatures. IFRF has developed a high-temperature sampling probe for sampling HCN and NH{sub 3}, which has been tested for sampling of NH{sub 3} by Chalmers University of Technology in Sweden. VTT Chemical Technology and Chalmers University of Technology have in their preliminary experiments determined contents of vaporous heavy metals in the combustion chamber of a 12 MW circulating fluidized-bed boiler using this probe. According to the results, the modified probe is suitable for heavy metal determination in combustion chamber. Based on this series of experiments, modification of the probe has been started on the own financing of VTT Chemical Technology and a field measurement was performed in November 1994 to test the present version of the probe. Based on the results of that measurement, the probe has been modified further on as a part of this LIEKKI 2 project. Similar kind of a principle has been applied in the probe which has been developed by VTT Energy during 1994. The probe is built for determination of gas composition of fluidized bed in full-scale boilers. The purpose of this project is to develop and test a sampling probe for fluidized bed combustion. The main advantage of the probe is that condensation losses in sampling due to high temperature gradients can be avoided. Thus, the probe is very suitable for sampling vaporous heavy and alkali metals and other condensing species as well as burning gases and alternatively also solids at high temperatures

Numerical investigation of biogas flameless combustion

International Nuclear Information System (INIS)

Hosseini, Seyed Ehsan; Bagheri, Ghobad; Wahid, Mazlan Abdul

2014-01-01

Highlights: • Fuel consumption decreases from 3.24 g/s in biogas conventional combustion to 1.07 g/s in flameless mode. • The differences between reactants and products temperature intensifies irreversibility in traditional combustion. • The temperature inside the chamber is uniform in biogas flameless mode and exergy loss decreases in this technique. • Low O 2 concentration in the flameless mode confirms a complete and quick combustion process in flameless regime. - Abstract: The purpose of this investigation is to analyze combustion characteristics of biogas flameless mode based on clean technology development strategies. A three dimensional (3D) computational fluid dynamic (CFD) study has been performed to illustrate various priorities of biogas flameless combustion compared to the conventional mode. The effects of preheated temperature and wall temperature, reaction zone and pollutant formation are observed and the impacts of combustion and turbulence models on numerical results are discussed. Although preheated conventional combustion could be effective in terms of fuel consumption reduction, NO x formation increases. It has been found that biogas is not eligible to be applied in furnace heat up due to its low calorific value (LCV) and it is necessary to utilize a high calorific value fuel to preheat the furnace. The required enthalpy for biogas auto-ignition temperature is supplied by enthalpy of preheated oxidizer. In biogas flameless combustion, the mean temperature of the furnace is lower than traditional combustion throughout the chamber. Compared to the biogas flameless combustion with uniform temperature, very high and fluctuated temperatures are recorded in conventional combustion. Since high entropy generation intensifies irreversibility, exergy loss is higher in biogas conventional combustion compared to the biogas flameless regime. Entropy generation minimization in flameless mode is attributed to the uniform temperature inside the chamber

Improvement of fire-tube boilers calculation methods by the numerical modeling of combustion processes and heat transfer in the combustion chamber

Science.gov (United States)

Komarov, I. I.; Rostova, D. M.; Vegera, A. N.

2017-11-01

This paper presents the results of study on determination of degree and nature of influence of operating conditions of burner units and flare geometric parameters on the heat transfer in a combustion chamber of the fire-tube boilers. Change in values of the outlet gas temperature, the radiant and convective specific heat flow rate with appropriate modification of an expansion angle and a flare length was determined using Ansys CFX software package. Difference between values of total heat flow and bulk temperature of gases at the flue tube outlet calculated using the known methods for thermal calculation and defined during the mathematical simulation was determined. Shortcomings of used calculation methods based on the results of a study conducted were identified and areas for their improvement were outlined.

Fluidized bed combustion: mixing and pollutant limitation

Energy Technology Data Exchange (ETDEWEB)

Leckner, B. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Energy Conversion

1997-10-01

Fluidized bed combustion (FBC) has been applied commercially during a few decades, and sufficient knowledge is gained to design boilers with sizes of up to several hundreds of megawatt thermal power (MW{sub th}). The knowledge of what goes on inside a large combustion chamber is still limited, however, and this impedes further optimization and efficient solution of problems that might occur. Despite this lack of knowledge the present survey deals with combustion chamber processes and discusses mixing and distribution of fuel and air in the combustion chamber and its importance for sulphur capture and reduction of emissions of nitrogen oxides. It is desirable to present the material in a general way and to cover the entire field of FBC. However, the scarce openly published information deals mostly with coal combustion in atmospheric circulating fluidized bed (CFB) combustors, and therefore this application will receive most attention, but reference is also made to pressurized combustion and to other fuels than coal. In this context the important work made in the LIEKKI project on the analysis of different fuels and on the influence of pressure should be especially pointed out. (orig.)

Engine combustion control via fuel reactivity stratification

Science.gov (United States)

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

2013-12-31

A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choose 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).

Experimental study of combustion behavior during continuous hydrogen injection with an operating igniter

Energy Technology Data Exchange (ETDEWEB)

Liang, Zhe, E-mail: zhe.liang@cnl.ca; Clouthier, Tony; Thomas, Bryan

2016-03-15

Highlights: • Combustion during continuous hydrogen release. • Periodical slow burning with a low release rate or weak turbulence. • Fast global burning with stratified hydrogen or strong turbulence. • Initiation of standing flame. - Abstract: Deliberate hydrogen ignition systems have been widely installed in many water cooled nuclear power plants to mitigate hydrogen risk in a loss-of-coolant accident. Experimental studies were performed at a large scale facility to simulate a post-accident containment scenario, where hydrogen is released into a volume (not closed) with an energized igniter. The test chamber had a volume of 60 m{sup 3}. The test parameters included hydrogen injection mass flow rate, injection elevation, igniter elevation, and level of turbulence in the chamber. Several dynamic combustion behaviors were observed. Under certain conditions, slow burning occurred periodically or locally without significant pressurization, and the hydrogen concentration could be maintained near the lean hydrogen flammability limit or a steady hydrogen distribution profile could be formed with a maximum hydrogen concentration less than 9 vol.%. Under other conditions, a global fast burn or a burn moving along the hydrogen dispersion pathway was observed and was followed by an immediate initiation of a standing flame. The study provided a better understanding of the dynamic combustion behavior induced by a deliberate igniter during a continuous hydrogen release. The data can be used for validation of combustion models used for hydrogen safety analysis.

Flex-flame burner and combustion method

Science.gov (United States)

Soupos, Vasilios; Zelepouga, Serguei; Rue, David M.; Abbasi, Hamid A.

2010-08-24

A combustion method and apparatus which produce a hybrid flame for heating metals and metal alloys, which hybrid flame has the characteristic of having an oxidant-lean portion proximate the metal or metal alloy and having an oxidant-rich portion disposed above the oxidant lean portion. This hybrid flame is produced by introducing fuel and primary combustion oxidant into the furnace chamber containing the metal or metal alloy in a substoichiometric ratio to produce a fuel-rich flame and by introducing a secondary combustion oxidant into the furnace chamber above the fuel-rich flame in a manner whereby mixing of the secondary combustion oxidant with the fuel-rich flame is delayed for a portion of the length of the flame.

Performance evaluation of Iranian cooling vest on the physiological indices in hot climatic chamber.

Science.gov (United States)

Dehghan, Habibollah; Gharehbaei, Somayeh; Mahaki, Behzad

2016-01-01

Heat stress is a threat to those who work in high temperatures. The purpose in this study was an examination of the cooling ability of Iranian phase change material (PCM) cold vest in hot and dry conditions in a climatic chamber. This experimental study was implemented on 12 male students (age 23.7 ± 2.8 years, weight 66.1 ± 11.4 kg, and VO2 max 2.53 L/min) in 2013. The heat strain score index (HSSI), skin temperature and oral temperature, and heartbeat in two phases with and without cooling vest was measured during 30 min in a climatic chamber (temperature 38.8 ± 1.3°C humidity ratio 32.9 ± 2.3%) and in two activity intensity of 2.4 and 4.8 km/h speed on the treadmill, and the data differences between groups "with" and "without" vest were tested by t-test and repeated measurement. The level of significance was considered as 0.05. The change in heartbeat at two activities, the oral temperature and heat strain score at 4.8 km/h, did not differ significantly between groups (with and without vest), as expected (P > 0.05). However, the change in skin temperature at two activities, oral temperature and heat strain score at 2.4 km/h, was significant between groups, as expected (P climate can affect the reduction of skin temperature, oral temperature, and HSSI in light activities.

Investigation of combustion characteristics of methane-hydrogen fuels

Science.gov (United States)

Vetkin, A. V.; Suris, A. L.; Litvinova, O. A.

2015-01-01

Numerical investigations of combustion characteristics of methane-hydrogen fuel used at present in tube furnaces of some petroleum refineries are carried out and possible problems related to change-over of existing furnaces from natural gas to methane-hydrogen fuel are analyzed. The effect of the composition of the blended fuel, associated temperature and emissivity of combustion products, temperature of combustion chamber walls, mean beam length, and heat release on variation in the radiation heat flux is investigated. The methane concentration varied from 0 to 100%. The investigations were carried out both at arbitrary given gas temperatures and at effective temperatures determined based on solving a set of equations at various heat-release rates of the combustion chamber and depended on the adiabatic combustion temperature and the temperature at the chamber output. The approximation dependence for estimation of the radiation heat exchange rate in the radiant chamber of the furnace at change-over to fuel with a greater hydrogen content is obtained. Hottel data were applied in the present work in connection with the impossibility to use approximated formulas recommended by the normative method for heat calculation of boilers to determine the gas emissivity, which are limited by the relationship of partial pressures of water steam and carbon dioxide in combustion products . The effect of the methane-hydrogen fuel on the equilibrium concentration of nitrogen oxides is also investigated.

Development of a cooling system and vacuum chamber for the pion tracker for HADES

Energy Technology Data Exchange (ETDEWEB)

Wirth, Joana [Technische Univ. Muenchen, Garching (Germany). Excellence Cluster Universe; Collaboration: HADES-Collaboration

2013-07-01

One of the future experiments planned at SIS18 with the HADES spectrometer in GSI Darmstadt envisages the employment of pion beam colliding on LH2 or nuclear target. Due to the fact that secondary pion beam has high momentum spread, since the precise knowledge of pion momentum is mandatory to carry out the planned exclusive measurements, we have to measure the momentum for each individual pion. For this purpose our group is developing a pion beam tracking system, which consists of two silicon detectors. Both detectors are located in the beamline and therefore have to cope the high-intensity secondary beam. Cooling of a silicon detector strongly improves its radiation hardness and performance. It reduces the leakage current and thus the noise, which is important for the detection of MIPs like pions. We have designed and built a complete prototype system of vacuum chamber and detector cooling. With use of the Finite Element Method we simulated the mechanical and thermal properties of the prototype. The proposed poster shows the current status and performance of the cooling system for a test-detector, focusing on the reduction of the leakage current and the noise.

Effects of ambient temperature and oxygen concentration on diesel spray combustion using a single-nozzle injector in a constant volume combustion chamber

KAUST Repository

Jing, Wei

2013-09-02

This work investigates the effects of ambient conditions on diesel spray combustion in an optically accessible, constant volume chamber using a single-nozzle fuel injector. The ambient O2 concentration was varied between five discrete values from 10% to 21% and three different ambient temperatures (800 K, 1000 K, and 1200 K). These conditions simulate different exhaust gas recirculation (EGR) levels and ambient temperatures in diesel engines. Both conventional diesel combustion and low temperature combustion (LTC) modes were observed under these conditions. A transient analysis and a quasi-steady state analysis are employed in this article. The transient analysis focuses on the flame development from beginning to the end, illustrating how the flame structure changes during this process; the quasi-steady state analysis focuses on the stable flame structure. The transient analysis was conducted using high-speed imaging of both OH* chemiluminescence and natural luminosity (NL). In addition, three different images were acquired using an ICCD camera, corresponding to OH* chemiluminescence, narrow-band flame emission at 430 nm (Band A) and at 470 nm (Band B), and were used to investigate the quasi-steady state combustion process. From the transient analysis, it was found that the NL signal becomes stronger and confined to narrow regions when the temperature and O2 concentration increase during the development of flame. The OH* intensity is much lower for the 10% ambient O2 and 800 K conditions compared to the higher temperatures and O2 levels. This implies the occurrence of LTC under these conditions. Results from the quasi-steady combustion stage indicate that high-temperature reactions effectively oxidize the soot in the downstream locations where only OH* signal is observed. In addition, an area was calculated for each spectral region, and results show that the area of Band A and Band B emissions in these images is larger than the area of OH* emissions at the lower O2

Effects of ambient temperature and oxygen concentration on diesel spray combustion using a single-nozzle injector in a constant volume combustion chamber

KAUST Repository

Jing, Wei; Roberts, William L.; Fang, Tiegang

2013-01-01

This work investigates the effects of ambient conditions on diesel spray combustion in an optically accessible, constant volume chamber using a single-nozzle fuel injector. The ambient O2 concentration was varied between five discrete values from 10% to 21% and three different ambient temperatures (800 K, 1000 K, and 1200 K). These conditions simulate different exhaust gas recirculation (EGR) levels and ambient temperatures in diesel engines. Both conventional diesel combustion and low temperature combustion (LTC) modes were observed under these conditions. A transient analysis and a quasi-steady state analysis are employed in this article. The transient analysis focuses on the flame development from beginning to the end, illustrating how the flame structure changes during this process; the quasi-steady state analysis focuses on the stable flame structure. The transient analysis was conducted using high-speed imaging of both OH* chemiluminescence and natural luminosity (NL). In addition, three different images were acquired using an ICCD camera, corresponding to OH* chemiluminescence, narrow-band flame emission at 430 nm (Band A) and at 470 nm (Band B), and were used to investigate the quasi-steady state combustion process. From the transient analysis, it was found that the NL signal becomes stronger and confined to narrow regions when the temperature and O2 concentration increase during the development of flame. The OH* intensity is much lower for the 10% ambient O2 and 800 K conditions compared to the higher temperatures and O2 levels. This implies the occurrence of LTC under these conditions. Results from the quasi-steady combustion stage indicate that high-temperature reactions effectively oxidize the soot in the downstream locations where only OH* signal is observed. In addition, an area was calculated for each spectral region, and results show that the area of Band A and Band B emissions in these images is larger than the area of OH* emissions at the lower O2

Experimental and numerical study of the active control of jets inside combustion chambers; Etude experimentale et numerique du controle actif de jets dans des chambres de combustion

Energy Technology Data Exchange (ETDEWEB)

Faivre, V

2003-12-15

Combustion instabilities occur when the flame heat release couples with the acoustic waves propagating in the combustion chamber. This phenomenon can lead to strong vibrations and noise but also, sometimes, to the complete combustion device failure. That is the reason why so many studies focus on the control of those instabilities. The method chosen in this study consists in an active control device (or set of actuators) having a strong effect on the mixing of the burner exhaust flow with the ambient fluid. The model configuration studied consists in a non reactive jet of air controlled by four small tangential secondary jets. Experiments have been carried out to optimize the control device geometry. The configuration identified as the most efficient, in terms of mixing enhancement, has been simulated through Large Eddy Simulations (LES). The objective of the numerical part of the present work is double. First, the numerical simulations provide a better understanding of the phenomena occurring when the control is on. Then, it is shown that LES can be considered as a tool to predict the effects of a control device on a flow. (author)

Measures for a quality combustion (combustion chamber exit and downstream); Mesures pour une combustion de qualite (sortie de chambre de combustion et en aval)

Energy Technology Data Exchange (ETDEWEB)

Epinat, G. [APAVE Lyonnaise, 69 (France)

1996-12-31

After a review of the different pollutants related to the various types of stationary and mobile combustion processes (stoichiometric, reducing and oxidizing combustion), measures and analyses than may be used to ensure the quality and efficiency of combustion processes are reviewed: opacimeters, UV analyzers, etc. The regulation and control equipment for combustion systems are then listed, according to the generator capacity level

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

KAUST Repository

Wolk, Benjamin

2013-07-01

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

Influence of cooled exhaust gas recirculation on performance, emissions and combustion characteristics of LPG fuelled lean burn SI engine

Science.gov (United States)

Ravi, K.; Pradeep Bhasker, J.; Alexander, Jim; Porpatham, E.

2017-11-01

On fuel perspective, Liquefied Petroleum Gas (LPG) provides cleaner emissions and also facilitates lean burn signifying less fuel consumption and emissions. Lean burn technology can attain better efficiencies and lesser combustion temperatures but this temperature is quite sufficient to facilitate formation of nitrogen oxide (NOx). Exhaust Gas Recirculation (EGR) for NOx reduction has been considered allover but extremely little literatures exist on the consequence of EGR on lean burn LPG fuelled spark ignition (SI) engine. The following research is carried out to find the optimal rate of EGR addition to reduce NOx emissions without settling on performance and combustion characteristics. A single cylinder diesel engine is altered to operate as LPG fuelled SI engine at a compression ratio of 10.5:1 and arrangements to provide different ratios of cooled EGR in the intake manifold. Investigations are done to arrive at optimum ratio of the EGR to reduce emissions without compromising on performance. Significant reductions in NOx emissions alongside HC and CO emissions were seen. Higher percentages of EGR further diluted the charge and lead to improper combustion and thus increased hydrocarbon emissions. Cooled EGR reduced the peak in-cylinder temperature which reduced NOx emissions but lead to misfire at lower lean limits.

Cooling the thermal grill illusion through self-touch.

Science.gov (United States)

Kammers, Marjolein P M; de Vignemont, Frédérique; Haggard, Patrick

2010-10-26

Acute peripheral pain is reduced by multisensory interactions at the spinal level [1]. Central pain is reduced by reorganization of cortical body representations [2, 3]. We show here that acute pain can also be reduced by multisensory integration through self-touch, which provides proprioceptive, thermal, and tactile input forming a coherent body representation [4, 5]. We combined self-touch with the thermal grill illusion (TGI) [6]. In the traditional TGI, participants press their fingers on two warm objects surrounding one cool object. The warm surround unmasks pain pathways, which paradoxically causes the cool object to feel painfully hot. Here, we warmed the index and ring fingers of each hand while cooling the middle fingers. Immediately after, these three fingers of the right hand were touched against the same three fingers on the left hand. This self-touch caused a dramatic 64% reduction in perceived heat. We show that this paradoxical release from paradoxical heat cannot be explained by low-level touch-temperature interactions alone. To reduce pain, we often clutch a painful hand with the other hand. We show here that self-touch not only gates pain signals reaching the brain [7-9] but also, via multisensory integration, increases coherence of cognitive body representations to which pain afferents project [10]. Copyright © 2010 Elsevier Ltd. All rights reserved.

Numerical Analysis on Combustion Characteristic of Leaf Spring Rotary Engine

Directory of Open Access Journals (Sweden)

Yan Zhang

2015-08-01

Full Text Available The purpose of this paper is to investigate combustion characteristics for rotary engine via numerical studies. A 3D numerical model was developed to study the influence of several operative parameters on combustion characteristics. A novel rotary engine called, “Leaf Spring Rotary Engine”, was used to illustrate the structure and principle of the engine. The aims are to (1 improve the understanding of combustion process, and (2 quantify the influence of rotational speed, excess air ratio, initial pressure and temperature on combustion characteristics. The chamber space changed with crankshaft rotation. Due to the complexity of chamber volume, an equivalent modeling method was presented to simulate the chamber space variation. The numerical simulations were performed by solving the incompressible, multiphase Unsteady Reynolds-Averaged Navier–Stokes Equations via the commercial code FLUENT using a transport equation-based combustion model; a realizable  turbulence model and finite-rate/eddy-dissipation model were used to account for the effect of local factors on the combustion characteristics.

Experimental study of acoustic damping induced by gas-liquid scheme injectors in a combustion chamber

International Nuclear Information System (INIS)

Kim, Hak Soon; Sohn, Chae Hoon

2007-01-01

In a liquid rocket engine, acoustic damping induced by gas-liquid scheme injectors is studied experimentally for combustion stability by adopting linear acoustic test. In the previous work, it has been found that gas-liquid scheme injector can play a significant role in acoustic damping or absorption when it is tuned finely. Based on this finding, acoustic-damping characteristics of multi-injectors are intensively investigated. From the experimental data, it is found that acoustic oscillations are almost damped out by multi-injectors when they have the tuning length proposed in the previous study. The length corresponds to a half wavelength of the first longitudinal overtone mode traveling inside the injector with the acoustic frequency intended for damping in the chamber. But, new injector-coupled acoustic modes show up in the chamber with the injectors of the tuning length although the target mode is nearly damped out. And, appreciable frequency shift is always observed except for the case of the worst tuned injector. Accordingly, it is proposed that the tuning length is adjusted to have the shorter length than a half wavelength when these phenomena are considered

Study on Combustion Characteristics and Propelling Projectile Motion Process of Bulk-Loaded Liquid Propellant

Science.gov (United States)

Xue, Xiaochun; Yu, Yonggang; Mang, Shanshan

2017-07-01

Data are presented showing that the problem of gas-liquid interaction instability is an important subject in the combustion and the propellant projectile motion process of a bulk-loaded liquid propellant gun (BLPG). The instabilities themselves arise from the sources, including fluid motion, to form a combustion gas cavity called Taylor cavity, fluid turbulence and breakup caused by liquid motion relative to the combustion chamber walls, and liquid surface breakup arising from a velocity mismatch on the gas-liquid interface. Typically, small disturbances that arise early in the BLPG combustion interior ballistic cycle can become amplified in the absence of burn rate limiting characteristics. Herein, significant attention has been given to developing and emphasizing the need for better combustion repeatability in the BLPG. Based on this goal, the concept of using different geometries of the combustion chamber is introduced and the concept of using a stepped-wall structure on the combustion chamber itself as a useful means of exerting boundary control on the combustion evolution to thus restrain the combustion instability has been verified experimentally in this work. Moreover, based on this background, the numerical simulation is devoted to a special combustion issue under transient high-pressure and high-temperature conditions, namely, studying the combustion mechanism in a stepped-wall combustion chamber with full monopropellant on one end that is stationary and the other end can move at high speed. The numerical results also show that the burning surface of the liquid propellant can be defined geometrically and combustion is well behaved as ignition and combustion progressivity are in a suitable range during each stage in this combustion chamber with a stepped-wall structure.

Experimental Study of Ignition by Hot Spot in Internal Combustion Engines

Science.gov (United States)

Serruys, Max

1938-01-01

In order to carry out the contemplated study, it was first necessary to provide hot spots in the combustion chamber, which could be measured and whose temperature could be changed. It seemed difficult to realize both conditions working solely on the temperature of the cooling water in a way so as to produce hot spots on the cylinder wall capable of provoking autoignition. Moreover, in the majority of practical cases, autoignition is produced by the spark plug, one of the least cooled parts in the engine. The first procedure therefore did not resemble that which most generally occurs in actual engine operation. All of these considerations caused us to reproduce similar hot spots at the spark plugs. The hot spots produced were of two kinds and designated with the name of thermo-electric spark plug and of metallic hot spot.

Ejector device for returning incomplete combustion products

Energy Technology Data Exchange (ETDEWEB)

Szule, T.; Minas, E.; Pietrowski, K.

1977-12-19

A device is proposed for separating the fine fraction of incompletely burned clinker and delivering it to the firebox for combustion. The clinker is fed into the two-chambered device from the top through an open gate. The inside chamber of the device consists of a side enclosure with an inspection hole and a hatch, and a gate with a screen on top. An ejector is located in the chamber. The case of the outside chamber, also with an inspection hole and hatch, forms a bypass channel with the enclosure of the inside chamber. Fine clinker is poured through the screen into the inside chamber, and some of it is removed by the ejector for combustion; the coarser fraction builds up on top of the gate, and is periodically passed through it. Large pieces of clinker which do not fit through the screen pass down through the bypass channel.

Combustion response to acoustic perturbation in liquid rocket engines

Science.gov (United States)

Ghafourian, Akbar

An experimental study of the effect of acoustic perturbations on combustion behavior of a model liquid propellant rocket engine has been carried out. A pair of compression drivers were used to excite transverse and longitudinal acoustic fields at strengths of up to 156.6 dB and 159.5 dB respectively in the combustion chamber of the experimental rocket engine. Propellant simulants were injected into the combustion chamber through a single element shear coaxial injector. Water and air were used in cold flow studies and ethanol and oxygen-enriched air were used as fuel and oxidizer in reacting hot flow studies. In cold flow studies an imposed transverse acoustic field had a more pronounced effect on the spray pattern than a longitudinal acoustic fields. A transverse acoustic field widened the spray by as much as 33 percent and the plane of impingement of the spray with chamber walls moved up closer to the injection plane. The behavior was strongly influenced by the gas phase velocity but was less sensitive to changes in the liquid phase velocity. In reacting hot flow studies the effects of changes in equivalence ratio, excitation amplitude, excitation frequency, liquid and gas phase velocity and chamber pressure on the response of the injector to imposed high frequency transverse acoustic excitation were measured. Reducing the equivalence ratio from 7.4 to 3.8 increased the chamber pressure response to the imposed excitation at 3000 Hz. Increasing the excitation amplitude from 147 dB to 155.6 dB at 3000 Hz increased the chamber pressure response to the excitation. In the frequency range of 1240 Hz to 3220 Hz, an excitation frequency of 3000 Hz resulted in the largest response of the chamber pressure indicating the importance of fluid dynamic coupling. Increasing the liquid phase velocity from 9.2 m/sec to 22.7 m/sec, did not change the amplitude of the chamber pressure response to excitation. This implied the importance of local equivalence ratio and not the overall

Applications of the Aqueous Self-Cooled Blanket concept

International Nuclear Information System (INIS)

Steiner, D.; Embrechts, M.J.; Varsamis, G.; Wrisley, K.; Deutch, L.; Gierszewski, P.

1986-01-01

In this paper a novel water-cooled blanket concept is examined. This concept, designated the Aqueous Self-Cooled Blanket (ASCB), employs water with small amounts of dissolved fertile compounds as both the coolant and the breeding medium. The ASCB concept is reviewed and its application in three different contexts is examined: (1) power reactors; (2) near-term devices such as NET; and (3) fusion-fission hybrids

Self-shielding characteristics of aqueous self-cooled blankets for next generation fusion devices

International Nuclear Information System (INIS)

Pelloni, S.; Cheng, E.T.; Embrechts, M.J.

1987-11-01

The present study examines self-shielding characteristics for two aqueous self-cooled tritium producing driver blankets for next generation fusion devices. The aqueous Self-Cooled Blanket concept (ASCB) is a very simple blanket concept that relies on just structural material and coolant. Lithium compounds are dissolved in water to provide for tritium production. An ASCB driver blanket would provide a low technology and low temperature environment for blanket test modules in a next generation fusion reactor. The primary functions of such a blanket would be shielding, energy removal and tritium production. One driver blanket considered in this study concept relates to the one proposed for the Next European Torus (NET), while the second concept is indicative for the inboard shield design for the Engineering Test Reactor proposed by the USA (TIBER II/ETR). The driver blanket for NET is based on stainless steel for the structural material and aqueous solution, while the inboard shielding blanket for TIBER II/ETR is based on a tungsten/aqueous solution combination. The purpose of this study is to investigate self-shielding and heterogeneity effects in aqueous self-cooled blankets. It is found that no significant gains in tritium breeding can be achieved in the stainless steel blanket if spatial and energy self-shielding effects are considered, and the heterogeneity effects are also insignificant. The tungsten blanket shows a 5 percent increase in tritium production in the shielding blanket when energy and spatial self-shielding effects are accounted for. However, the tungsten blanket shows a drastic increase in the tritium breeding ratio due to heterogeneity effects. (author) 17 refs., 9 figs., 9 tabs

Two-coordinate mini drift chamber operating in a self-quenching streamer mode

International Nuclear Information System (INIS)

Chernenko, S.P.; Smykov, L.P.; Zanevskij, Yu.V.

1993-01-01

Two-coordinate mini drift chambers operating in a self-quenching streamer mode have been developed. The tests have demonstrated these chambers to possess an extended counting plateau, a high operating stability and a high uniformity of efficiency over detecting area. The space resolution along anode wires is not worse than 250μm; the expected space resolution for the second coordinate is about 100 μm

Experimental and computational studies of film cooling with compound angle injection

Energy Technology Data Exchange (ETDEWEB)

Goldstein, R.J.; Eckert, E.R.G.; Patankar, S.V. [Univ. of Minnesota, Minneapolis, MN (United States)] [and others

1995-10-01

The thermal efficiency of gas turbine systems depends largely on the turbine inlet temperature. Recent decades have seen a steady rise in the inlet temperature and a resulting reduction in fuel consumption. At the same time, it has been necessary to employ intensive cooling of the hot components. Among various cooling methods, film cooling has become a standard method for cooling of the turbine airfoils and combustion chamber walls. The University of Minnesota program is a combined experimental and computational study of various film-cooling configurations. Whereas a large number of parameters influence film cooling processes, this research focuses on compound angle injection through a single row and through two rows of holes. Later work will investigate the values of contoured hole designs. An appreciation of the advantages of compound angle injection has risen recently with the demand for more effective cooling and with improved understanding of the flow; this project should continue to further this understanding. Approaches being applied include: (1) a new measurement system that extends the mass/heat transfer analogy to obtain both local film cooling and local mass (heat) transfer results in a single system, (2) direct measurement of three-dimensional turbulent transport in a highly-disturbed flow, (3) the use of compound angle and shaped holes to optimize film cooling performance, and (4) an exploration of anisotropy corrections to turbulence modeling of film cooling jets.

49 CFR 173.220 - Internal combustion engines, self-propelled vehicles, mechanical equipment containing internal...

Science.gov (United States)

2010-10-01

... and vehicles with certain electronic equipment when transported by aircraft or vessel. When an... vehicles, mechanical equipment containing internal combustion engines, and battery powered vehicles or... Than Class 1 and Class 7 § 173.220 Internal combustion engines, self-propelled vehicles, mechanical...

Evidence of refilled chamber gas pressure enhancing cooling rate during melt spinning of a Zr50Cu40Al10 alloy

Directory of Open Access Journals (Sweden)

Hong-wang Yang

2015-07-01

Full Text Available The influence of the refilled gas pressure on the glass forming behaviour of one of the best ternary glass forming alloys Zr50Cu40Al10 was studied for the melt spinning process. The amorphicity of as-quenched ribbons was characterized by X-ray diffraction (XRD and differential scanning calorimetry (DSC. The refilled chamber atmospheric pressure is crucial to the cooling rate of melt spinning. At high vacuum, at pressure less than 0.0001 atm, fully crystalline fragments are obtained. Monolithic amorphous ribbons were only obtained at a gas pressure of 0.1 atm or higher. The extended contact length between thecribbons and the copper wheel contributes to the high cooling rate of melt spinning. Higher chamber gas pressure leads to more turbulence of liquid metal beneath the nozzle; therefore, lower pressure is preferable at practical melt spinning processes once glass forming conditions are fulfilled.

Self-ignition combustion synthesis of TiFe in hydrogen atmosphere

Energy Technology Data Exchange (ETDEWEB)

Wakabayashi, R. [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)], E-mail: ryuta@eng.hokudai.ac.jp; Sasaki, S. [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Saita, I. [National Institute of Advanced Industrial Science and Technology (AIST), AIST Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Sato, M. [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Uesugi, H. [Bio Coke Lab., Ltd., 5-34-20 Hirato, Totsuka-ku, Yokohama, Kanagawa 244-0802 (Japan); Akiyama, T. [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

2009-07-08

This paper describes the self-ignition combustion synthesis (SICS) of highly active titanium iron (TiFe) in a high-pressure hydrogen atmosphere without employing an activation process. In the experiments, well-mixed powders of Ti and Fe in the molar ratio of 1:1 were uniformly heated up to 1085 deg. C, the eutectic temperature of Ti-Fe binary system, in pressurized hydrogen at 0.9 MPa. The electric source was disconnected immediately after the ignition between Ti and Fe, and the mixture was cooled naturally. In this study, the exothermic reaction Ti + Fe = TiFe + 40 kJ occurred at around 1085 deg. C after the hydrogenation and decomposition of Ti. X-ray diffraction analysis showed that the final product had only one phase-TiFeH{sub 0.06}-which can store hydrogen of 1.55 mass% under hydrogen pressure of 4 MPa. The product obtained by SICS contained considerably more hydrogen quickly as compared to the commercially available product; this fact can be explained by the porous structure of the obtained product, which was observed using a scanning electron microscope. In conclusion, the SICS of TiFe saved time and energy, yields products with high porosity and small crystals, enabled easy hydrogenation, and did not require activation processes.

Numerical investigation of the flow inside the combustion chamber of a plant oil stove

Science.gov (United States)

Pritz, B.; Werler, M.; Wirbser, H.; Gabi, M.

2013-10-01

Recently a low cost cooking device for developing and emerging countries was developed at KIT in cooperation with the company Bosch und Siemens Hausgeräte GmbH. After constructing an innovative basic design further development was required. Numerical investigations were conducted in order to investigate the flow inside the combustion chamber of the stove under variation of different geometrical parameters. Beyond the performance improvement a further reason of the investigations was to rate the effects of manufacturing tolerance problems. In this paper the numerical investigation of a plant oil stove by means of RANS simulation will be presented. In order to reduce the computational costs different model reduction steps were necessary. The simulation results of the basic configuration compare very well with experimental measurements and problematic behaviors of the actual stove design could be explained by the investigation.

Spectroscopy, Kinetics, and Dynamics of Combustion Radicals

Energy Technology Data Exchange (ETDEWEB)

Nesbitt, David J. [Research/Professor

2013-08-06

Spectroscopy, kinetics and dynamics of jet cooled hydrocarbon transients relevant to the DOE combustion mission have been explored, exploiting i) high resolution IR lasers, ii) slit discharge sources for formation of jet cooled radicals, and iii) high sensitivity detection with direct laser absorption methods and near the quantum shot noise limit. What makes this combination powerful is that such transients can be made under high concentrations and pressures characteristic of actual combustion conditions, and yet with the resulting species rapidly cooled (T ≈10-15K) in the slit supersonic expansion. Combined with the power of IR laser absorption methods, this provides novel access to spectral detection and study of many critical combustion species.

Plasma igniter for internal combustion engine

Science.gov (United States)

Fitzgerald, D. J.; Breshears, R. R. (Inventor)

1978-01-01

An igniter for the air/fuel mixture used in the cylinders of an internal combustion engine is described. A conventional spark is used to initiate the discharge of a large amount of energy stored in a capacitor. A high current discharge of the energy in the capacitor switched on by a spark discharge produces a plasma and a magnetic field. The resultant combined electromagnetic current and magnetic field force accelerates the plasma deep into the combustion chamber thereby providing an improved ignition of the air/fuel mixture in the chamber.

Analysis of the microturbine combustion chamber by using the CHEMKIN III computer code; Analise da camara de combustao de microturbinas empregando-se o codigo computacional CHEMKIN III

Energy Technology Data Exchange (ETDEWEB)

Madela, Vinicius Zacarias; Pauliny, Luis F. de A.; Veras, Carlos A. Gurgel [Brasilia Univ., DF (Brazil). Dept. de Engenharia Mecanica]. E-mail: gurgel@enm.unb.br; Costa, Fernando de S. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Combustao e Propulsao]. E-mail: fernando@cptec.inpe.br

2000-07-01

This work presents the results obtained with the simulation of multi fuel micro turbines combustion chambers. In particular, the predictions for the methane and Diesel burning are presented. The appropriate routines of the CHEMKIN III computer code were used.

Vacuum Chambers for LEP sections

CERN Multimedia

1983-01-01

The picture shows sections of the LEP vacuum chambers to be installed in the dipole magnets (left) and in the quadrupoles (right). The dipole chamber has three channels: the beam chamber, the pumping duct where the NEG (non-evaporabe getter) is installed and the water channel for cooling (on top in the picture). The pumping duct is connected to the beam chamber through holes in the separating wall. The thick lead lining to shield radiation can also be seen. These chambers were manufactured as extruded aluminium alloy profiles.

In-reactor testing of self-powered neutron detectors and miniature fission chambers

International Nuclear Information System (INIS)

Duchene, J.; LeMeur, R.; Verdant, R.

1975-01-01

The CEA has tested a variety of ''slow'' self-powered neutron detectors with rhodium, silver and vanadium emitters. Currently there are 120 vanadium detectors in the EL4 heavy water reactor. In addition, ''fast'' detectors with cobalt emitters have been tested at Saclay and 50 of these are in reactor. Other studies are concerned with 6 mm diameter miniature fission chambers. Two fast response chambers with argon-nitrogen filling gas became slow during irradiation, but operated to 600 deg C. An argon filled chamber of 4.7 mm diameter, for traversing in core system in pressurized water reactor, has shown satisfactory test results. (author)

Cálculo de la temperatura en el interior de la cámara de combustión en motores de combustión interna. // Calculation of temperature into combustion chamber of internal combustion engines.

Directory of Open Access Journals (Sweden)

F. Soto Pau

2002-05-01

Full Text Available El trabajo aquí presentado tiene como objetivo llegar a expresiones de cálculo de la temperatura en el interior de la cámarade combustión como vía de diagnostico de la combustión en motores térmicos. Este trabajo consiste en un modelo físicomatemático,el cual usa como herramientas fundamentalmente, los valores de presión medidos en el interior de la cámarade combustión, las características geométricas del motor y todos los valores normalmente medidos en el bancodinamométrico. El procesamiento teórico de este modelo consiste fundamentalmente en la determinación de la evoluciónde la combustión a partir de la curva de presión, basada en la Primera Ley de la Termodinámica, adoptando Modelo deGases Perfectos. A partir de la posición angular de cierre de la válvula de admisión es posible calcular la derivada de latemperatura en relación a la posición angular del cigüeñal para los gases quemados T&b y no quemados T&u . Teniendo estosvalores de T&u y T&b calculados, es posible integrar numéricamente las temperaturas utilizando el método de integración deEuler. Conociendo la composición química del combustible, es posible calcular la temperatura adiabática de llama, estesería el valor de temperatura inicial Tb que nos permitiría calcular un valor de entalpía específica de los gases quemados. Deigual forma con el valor de la temperatura inicial para los gases no quemados Tu se tiene el valor de temperatura inicial parael proceso de integración.Palabras claves: Proceso de combustión en motores térmicos, temperatura en el interior de la cámara decombustión, presión en el interior de la cámara de combustión.____________________________________________________________________________Abstract.This paper presents calculation expressions of the temperature inside the combustion chamber in order to diagnose thecombustion in termic engines. This analysis consists in a physical-mathematical model, which uses

SELF-CONVERGENCE OF RADIATIVELY COOLING CLUMPS IN THE INTERSTELLAR MEDIUM

International Nuclear Information System (INIS)

Yirak, Kristopher; Frank, Adam; Cunningham, Andrew J.

2010-01-01

Isolated regions of higher density populate the interstellar medium (ISM) on all scales-from molecular clouds, to the star-forming regions known as cores, to heterogeneous ejecta found near planetary nebulae and supernova remnants. These clumps interact with winds and shocks from nearby energetic sources. Understanding the interactions of shocked clumps is vital to our understanding of the composition, morphology, and evolution of the ISM. The evolution of shocked clumps is well understood in the limiting 'adiabatic' case where physical processes such as self-gravity, heat conduction, radiative cooling, and magnetic fields are ignored. In this paper, we address the issue of evolution and convergence when one of these processes-radiative cooling-is included. Numeric convergence studies demonstrate that the evolution of an adiabatic clump is well captured by roughly 100 cells per clump radius. The presence of radiative cooling, however, imposes limits on the problem due to the removal of thermal energy. Numerical studies which include radiative cooling typically adopt the 100-200 cells per clump radius resolution. In this paper, we present the results of a convergence study for radiatively cooling clumps undertaken over a broad range of resolutions, from 12 to 1536 cells per clump radius, employing adaptive mesh refinement (AMR) in a two-dimensional axisymmetric geometry (2.5 dimensions). We also provide a fully three-dimensional simulation, at 192 cells per clump radius, which supports our 2.5 dimensional results. We find no appreciable self-convergence at ∼100 cells per clump radius as small-scale differences owing to increasingly resolving the cooling length have global effects. We therefore conclude that self-convergence is an insufficient criterion to apply on its own when addressing the question of sufficient resolution for radiatively cooled shocked clump simulations. We suggest the adoption of alternate criteria to support a statement of sufficient

Influence of the combustion chamber during the transient performance of gas turbines; Influencias da camara de combustao durante o transitorio de turbinas a gas

Energy Technology Data Exchange (ETDEWEB)

Cunha Alves, M.A. da [Centro Tecnico Aeroespacial, Sao Jose dos Campos, SP (Brazil). Inst. de Pesquisas e Desenvolvimento

1991-12-31

It has been realised that heat transfer and others secondary effects have an important influence on the transient performance of a gas turbine, but until very recently, modelling was carried out either assuming adiabatic conditions, or using expedient but unrealistic models to simulate these effects. This work describes the effects of combustion chamber heat storage and of dead time lag of the combustion process, during a gas turbine transient. These effects have been investigated and the analysis has indicated that these effects do not play an important role in the transient performance of the engine analysed, but in certain circumstances they may become important. (author). 5 refs., 4 figs.

System and method for reducing combustion dynamics in a combustor

Science.gov (United States)

Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; Srinivasan, Shiva; York, William David

2016-11-29

A system for reducing combustion dynamics in a combustor includes an end cap that extends radially across the combustor and includes an upstream surface axially separated from a downstream surface. A combustion chamber is downstream of the end cap, and tubes extend from the upstream surface through the downstream surface. Each tube provides fluid communication through the end cap to the combustion chamber. The system further includes means for reducing combustion dynamics in the combustor. A method for reducing combustion dynamics in a combustor includes flowing a working fluid through tubes that extend axially through an end cap that extends radially across the combustor and obstructing at least a portion of the working fluid flowing through a first set of the tubes.

Combustion suppressing device for leaked sodium

International Nuclear Information System (INIS)

Ooto, Akihiro.

1985-01-01

Purpose: To suppress the atmospheric temperature to secure the building safety and shorten the recovery time after the leakage in a chamber for containing sodium leaked from coolant circuit equipments or pipeways of LMFBR type rector by suppressing the combustion of sodium contained in the chamber. Constitution: To the inner wall of a chamber for containing sodium handling equipments, are vertically disposed a panel having a coolant supply port at the upper portion and a coolant discharge port at the lower portion thereof and defined with a coolant flowing channel and a panel for sucking the coolant discharged from the abovementioned panel and exhausting the same externally. Further, a corrugated combustion suppressing plate having apertures for draining the condensated leaked sodium is disposed near the sodium handling equipments. If ruptures are resulted to the sodium handling equipments or pipeway, leaked sodium is passed through the drain apertures in the suppressing plate and stored at the bottom of the containing chamber. (Horiuchi, T.)

Effect of Metal Additives on the Combustion Characteristics of High-Energy Materials

Directory of Open Access Journals (Sweden)

Korotkikh Alexander

2016-01-01

Full Text Available Thermodynamic calculation of combustion parameters and equilibrium composition of HEMs combustion products showed, that at the increase of aluminum powder dispersity the specific impulse and combustion temperature of solid propellants are reduced due to the decrease of the mass fraction of active aluminum in particles. Partial or complete replacement of aluminum by metal powder (B, Mg, AlB2, Al\\Mg alloy, Fe, Ti and Zr in HEMs composition leads to the reduce of the specific impulse and combustion temperature. Replacement of aluminum powder by boron and magnesium in HEM reduces the mass fraction of condensed products in the combustion chamber of solid rocket motor. So, for compositions HEMs with boron and aluminum boride the mass fraction in chamber is reduced by 24 and 36 %, respectively, with respect to the composition HEMs with Al powder. But the mass fraction of CCPs in the nozzle exit increases by 13 % for HEMs with aluminum boride due to the formation of boron oxide in the condensed combustion products. Partial replacement of 2 wt. % aluminum powder by iron and copper additives in HEM leads to the reduce of CCPs mass fraction in chamber by 4–10 % depending on the aluminum powder dispersity duo to these metals are not formed condensed products at the HEMs combustion in chamber.

Fast Ignition and Sustained Combustion of Ionic Liquids

Science.gov (United States)

Joshi, Prakash B. (Inventor); Piper, Lawrence G. (Inventor); Oakes, David B. (Inventor); Sabourin, Justin L. (Inventor); Hicks, Adam J. (Inventor); Green, B. David (Inventor); Tsinberg, Anait (Inventor); Dokhan, Allan (Inventor)

2016-01-01

A catalyst free method of igniting an ionic liquid is provided. The method can include mixing a liquid hypergol with a HAN (Hydroxylammonium nitrate)-based ionic liquid to ignite the HAN-based ionic liquid in the absence of a catalyst. The HAN-based ionic liquid and the liquid hypergol can be injected into a combustion chamber. The HAN-based ionic liquid and the liquid hypergol can impinge upon a stagnation plate positioned at top portion of the combustion chamber.

E25 stratified torch ignition engine performance, CO_2 emission and combustion analysis

International Nuclear Information System (INIS)

Rodrigues Filho, Fernando Antonio; Moreira, Thiago Augusto Araujo; Valle, Ramon Molina; Baêta, José Guilherme Coelho; Pontoppidan, Michael; Teixeira, Alysson Fernandes

2016-01-01

Highlights: • A torch ignition engine prototype was built and tested. • Significant reduction of BSFC was achieved due to the use of the torch ignition system. • Low cyclic variability characterized the lean combustion process of the torch ignition engine prototype. • The torch ignition system allowed an average reduction of 8.21% at the CO_2 specific emissions. - Abstract: Vehicular emissions significantly increase atmospheric air pollution and the greenhouse effect. This fact associated with the fast growth of the global motor vehicle fleet demands technological solutions from the scientific community in order to achieve a decrease in fuel consumption and CO_2 emission, especially of fossil fuels to comply with future legislation. To meet this goal, a prototype stratified torch ignition engine was designed from a commercial baseline engine. In this system, the combustion starts in a pre-combustion chamber where the pressure increase pushes the combustion jet flames through a calibrated nozzle to be precisely targeted into the main chamber. These combustion jet flames are endowed with high thermal and kinetic energy being able to promote a stable lean combustion process. The high kinetic and thermal energy of the combustion jet flame results from the load stratification. This is carried out through direct fuel injection in the pre-combustion chamber by means of a prototype gasoline direct injector (GDI) developed for low fuel flow rate. During the compression stroke, lean mixture coming from the main chamber is forced into the pre-combustion chamber and, a few degrees before the spark timing, fuel is injected into the pre-combustion chamber aiming at forming a slightly rich mixture cloud around the spark plug which is suitable for the ignition and kernel development. The performance of the torch ignition engine running with E25 is presented for different mixture stratification levels, engine speed and load. The performance data such as combustion phasing

Combustion Dynamics and Stability Modeling of a Liquid Oxygen/RP-2 Oxygen-Rich Staged Combustion Preburner and Thrust Chamber Assembly with Gas-Centered Swirl Coaxial Injector Elements

Science.gov (United States)

Casiano, M. J.; Kenny, R. J.; Protz, C. S.; Garcia, C. P.; Simpson, S. P.; Elmore, J. L.; Fischbach, S. R.; Giacomoni, C. B.; Hulka, J. R.

2016-01-01

The Combustion Stability Tool Development (CSTD) project, funded by the Air Force Space and Missile Systems Center, began in March 2015 supporting a renewed interest in the development of a liquid oxygen/hydrocarbon, oxygen-rich combustion engine. The project encompasses the design, assembly, and hot-fire testing of the NASA Marshall Space Flight Center 40-klbf Integrated Test Rig (MITR). The test rig models a staged-combustion configuration by combining an oxygen-rich preburner (ORPB), to generate hot gas, with a thrust chamber assembly (TCA) using gas-centered swirl coaxial injector elements. There are five separately designed interchangeable injectors in the TCA that each contain 19- or 27- injector elements. A companion paper in this JANNAF conference describes the design characteristics, rationale, and fabrication issues for all the injectors. The data acquired from a heavily instrumented rig encompasses several injectors, several operating points, and stability bomb tests. Another companion paper in this JANNAF conference describes this test program in detail. In this paper, dynamic data from the hot-fire testing is characterized and used to identify the responses in the ORPB and TCA. A brief review of damping metrics are discussed and applied as a measure of stability margin for damped acoustic modes. Chug and longitudinal combustion stability models and predictions are described which includes new dynamic models for compressible flow through an orifice and a modification to incorporate a third feed line for inclusion of the fuel-film coolant. Flow-acoustics finite element modeling is used to investigate the anticipated TCA acoustics, the effects of injector element length on stability margin, and the potential use of an ORPB orifice trip ring for improving longitudinal stability margin.

High resolution drift chambers

International Nuclear Information System (INIS)

Va'vra, J.

1985-07-01

High precision drift chambers capable of achieving less than or equal to 50 μm resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs

KEROMIX. Sub-project: Basic experimental studies on mixing in swirl flow in gas turbine combustion chambers. Final report; KEROMIX. Arbeitspaket: Grundlegende experimentelle Untersuchungen der Mischungsvorgaenge drallbehafteter Stroemungen in Gasturbinenbrennkammern. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Hennecke, D K

2000-07-01

This report describes investigations on advanced lean fuel combustion technologies with stable and low-pollution combustion in an aircraft gas turbine in all load stages. The key factors, i.e. stability and low pollutant concentrations, are closely related to the mixing characteristic of the combustion chamber. Lean fuel combustion does not go well with stable combustion which is indispensable inan aircraft engine. Further, the lean mixture must be maintained throughout the combustion chamber as local stoichiometries would automatically result in higher concentrations of nitric oxides. To solve the problems related to these processes, detailed knowledge of the mixing processes is required. [German] Als Teilprojekt des Vorhabens 'KEROMIX, stabile, schadstoffarme Magerverbrennung' leistet die vorliegende Arbeit einen wichtigen Beitrag zur Beherrschung fortschrittlicher Verbrennungstechniken unter Anwendung des Mager-Konzeptes. Im Rahmen des Verbundprogrammes zum Technologieprogramm ENGINE 3E steht die Entwicklung von Verbrennungskonzepten, die eine stabile und schadstoffarme Verbrennung ueber den gesamten Lastbereich einer Flugzeug-Gasturbine hinweg gewaehrleisten. Die hier entscheidenden Attribute der Verbrennung, naemlich Stabilitaet und Schadstoffarmut sind eng mit der Mischungscharakteristik einer Brennkammer verbunden. Hier gilt es, die zum Teil gegenlaeufigen Effekte, die in einer Brennkammer auftreten, kontrollierbar zu machen. So steht die zur Verminderung der Stickoxidproduktion geforderte magere Verbrennung im ausgesprochenen Gegensatz zur Forderung einer in allen Betriebsbereichen stabilen Verbrennung, die allein schon aus Flugsicherheitsgruenden unabdingbar ist. Desweiteren muss der magere Gemischzustand unbedingt in der gesamten Brennkammer eingehalten werden, da lokale stoechiometrische Zustaende sofort zum Anstieg der Stickoxidproduktion fuehren. Um diese Prozesse beherrschen zu koennen, ist eine detaillierte Kenntnis der Mischungsvorgaenge bezueglich

Experimental study on combustion of biomass micron fuel (BMF) in cyclone furnace

International Nuclear Information System (INIS)

Luo Siyi; Xiao Bo; Hu Zhiquan; Liu Shiming; He Maoyun

2010-01-01

Based on biomass micron fuel (BMF) with particle size less than 250 μm, a cyclone combustion concept was presented and a lab-scale cyclone furnace was designed to evaluate the feasibility. The influences of equivalence ration (ER) and particle size of BMF on combustion performance were studied, as well as temperature distribution in the combustion chamber. The results show that BMF combustion in the cyclone furnace is reliable, with rational temperature distribution inside furnace hearth, lower CO emission, soot concentration and C content in ashes. As ER being 1.2, the temperature in the chamber is maximized up to 1200 deg. C. Smaller particles results in better combustion performances.

E25 stratified torch ignition engine emissions and combustion analysis

International Nuclear Information System (INIS)

Rodrigues Filho, Fernando Antonio; Baêta, José Guilherme Coelho; Teixeira, Alysson Fernandes; Valle, Ramón Molina; Fonseca de Souza, José Leôncio

2016-01-01

Highlights: • A stratified torch ignition (STI) engine was built and tested. • The STI engines was tested in a wide range of load and speed. • Significant reduction on emissions was achieved by means of the STI system. • Low cyclic variability characterized the lean combustion process of the torch ignition engine. • HC emission is the main drawback of the stratified torch ignition engine. - Abstract: Vehicular emissions significantly increase atmospheric air pollution and greenhouse gases (GHG). This fact associated with fast global vehicle fleet growth calls for prompt scientific community technological solutions in order to promote a significant reduction in vehicle fuel consumption and emissions, especially of fossil fuels to comply with future legislation. To meet this goal, a prototype stratified torch ignition (STI) engine was built from a commercial existing baseline engine. In this system, combustion starts in a pre-combustion chamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main chamber. These combustion jet flames are endowed with high thermal and kinetic energy, being able to generate a stable lean combustion process. The high kinetic and thermal energy of the combustion jet flame results from the load stratification. This is carried out through direct fuel injection in the pre-combustion chamber by means of a prototype gasoline direct injector (GDI) developed for a very low fuel flow rate. In this work the engine out-emissions of CO, NOx, HC and CO_2 of the STI engine are presented and a detailed analysis supported by the combustion parameters is conducted. The results obtained in this work show a significant decrease in the specific emissions of CO, NOx and CO_2 of the STI engine in comparison with the baseline engine. On the other hand, HC specific emission increased due to wall wetting from the fuel hitting in the pre-combustion chamber wall.

Experimental investigation concerning the influence of fuel type and properties on the injection and atomization of liquid biofuels in an optical combustion chamber

International Nuclear Information System (INIS)

Galle, J.; Defruyt, S.; Van de Maele, C.; Rodriguez, R. Piloto; Denon, Q.; Verliefde, A.; Verhelst, S.

2013-01-01

Due to the scarcity of fossil fuels and the future stringent emission limits, there is an increasing interest for the use of renewable biofuels in compression ignition engines. However, these fuels have different physical, chemical and thermodynamic properties affecting atomization, spray development and combustion processes. The results reported in this paper have been obtained by experimentation with a constant volume combustion chamber. The influences of physical fuel properties on injections under non-evaporating conditions are studied, using a pump-line-nozzle system from a medium speed diesel engine with injection pressures up to 1200 bar, by changing the fuel type and temperature. Experiments were conducted for diesel, biodiesel, straight vegetable oils and animal fats. Injection pressure and needle lift measurements were analyzed. A high speed camera was used to visualize the spray, which enabled us to study the spray penetration and spray angle. Our results show that the fuel temperature is an important parameter to control because it significantly affects the fuel properties. Both the injection timing and injection duration are affected by the fuel properties. The influences of these properties on the spray development were less pronounced. At low temperatures, a strongly deteriorated atomization of oils and fats was observed. -- Highlights: • Spray measurements in an optical combustion chamber. • Influence on the injections system is compared for different bio-fuels. •Temperature effects the fuel properties, with strong influence on the injection system. • Viscosity has significant influence on atomization, especially for viscous fuels. • No difference for spray penetration and angle unlike the mass distribution

New class of combustion processes

International Nuclear Information System (INIS)

Merzhanov, A.G.; Borovinskaya, I.P.

1975-01-01

A short review is given of the results of work carried out since 1967 on studying the combustion processes caused by the interaction of chemical elements in the condensed phase and leading to the formation of refractory compounds. New phenomena and processes are described which are revealed when investigating the combustion of the systems of this class, viz solid-phase combustion, fast combustion in the condensed phase, filtering combustion, combustion in liquid nitrogen, spinning combustion, self-oscillating combustion, and repeated combustion. A new direction in employment of combustion processes is discussed, viz. a self-propagating high-temperature synthesis of refractory nitrides, carbides, borides, silicides and other compounds

Thermo-acoustic instabilities of high-frequency combustion in rocket engines; Instabilites thermo-acoustiques de combustion haute-frequence dans les moteurs fusees

Energy Technology Data Exchange (ETDEWEB)

Cheuret, F

2005-10-15

Rocket motors are confined environments where combustion occurs in extreme conditions. Combustion instabilities can occur at high frequencies; they are tied to the acoustic modes of the combustion chamber. A common research chamber, CRC, allows us to study the response of a turbulent two-phase flame to acoustic oscillations of low or high amplitudes. The chamber is characterised under cold conditions to obtain, in particular, the relative damping coefficient of acoustic oscillations. The structure and frequency of the modes are determined in the case where the chamber is coupled to a lateral cavity. We have used a powder gun to study the response to a forced acoustic excitation at high amplitude. The results guide us towards shorter flames. The injectors were then modified to study the combustion noise level as a function of injection conditions. The speed of the gas determines whether the flames are attached or lifted. The noise level of lifted flames is higher. That of attached flames is proportional to the Weber number. The shorter flames whose length is less than the radius of the CRC, necessary condition to obtain an effective coupling, are the most sensitive to acoustic perturbations. The use of a toothed wheel at different positions in the chamber allowed us to obtain informations on the origin of the thermo-acoustic coupling, main objective of this thesis. The flame is sensitive to pressure acoustic oscillations, with a quasi-zero response time. These observations suggest that under the conditions of the CRC, we observe essentially the response of chemical kinetics to pressure oscillations. (author)

IEA combustion agreement : a collaborative task on alternative fuels in combustion

International Nuclear Information System (INIS)

Larmi, M.

2009-01-01

The focus of the alternative fuels in combustion task of the International Energy Agency is on high efficiency engine combustion, furnace combustion, and combustion chemistry. The objectives of the task are to develop optimum combustion for dedicated fuels by fully utilizing the physical and chemical properties of synthetic and renewable fuels; a significant reduction in carbon dioxide, NOx and particulate matter emissions; determine the minimum emission levels for dedicated fuels; and meet future emission standards of engines without or with minimum after-treatment. This presentation discussed the alternative fuels task and addressed issues such as synthetic fuel properties and benefits. The anticipated future roadmap was presented along with a list of the synthetic and renewable engine fuels to be studied, such as neat oxygenates like alcohols and ethers, biogas/methane and gas combustion, fuel blends, dual fuel combustion, high cetane number diesel fuels like synthetic Fischer-Tropsch diesel fuel and hydrogenated vegetable oil, and low CN number fuels. Implementation examples were also discussed, such as fuel spray studies in optical spray bombs; combustion research in optical engines and combustion chambers; studies on reaction kinetics of combustion and emission formation; studies on fuel properties and ignition behaviour; combustion studies on research engines; combustion optimization; implementing the optimum combustion in research engines; and emission measurements. Overall milestone examples and the overall schedule of participating countries were also presented. figs.

Stratified charge rotary engine combustion studies

Science.gov (United States)

Shock, H.; Hamady, F.; Somerton, C.; Stuecken, T.; Chouinard, E.; Rachal, T.; Kosterman, J.; Lambeth, M.; Olbrich, C.

1989-07-01

Analytical and experimental studies of the combustion process in a stratified charge rotary engine (SCRE) continue to be the subject of active research in recent years. Specifically to meet the demand for more sophisticated products, a detailed understanding of the engine system of interest is warranted. With this in mind the objective of this work is to develop an understanding of the controlling factors that affect the SCRE combustion process so that an efficient power dense rotary engine can be designed. The influence of the induction-exhaust systems and the rotor geometry are believed to have a significant effect on combustion chamber flow characteristics. In this report, emphasis is centered on Laser Doppler Velocimetry (LDV) measurements and on qualitative flow visualizations in the combustion chamber of the motored rotary engine assembly. This will provide a basic understanding of the flow process in the RCE and serve as a data base for verification of numerical simulations. Understanding fuel injection provisions is also important to the successful operation of the stratified charge rotary engine. Toward this end, flow visualizations depicting the development of high speed, high pressure fuel jets are described. Friction is an important consideration in an engine from the standpoint of lost work, durability and reliability. MSU Engine Research Laboratory efforts in accessing the frictional losses associated with the rotary engine are described. This includes work which describes losses in bearing, seal and auxillary components. Finally, a computer controlled mapping system under development is described. This system can be used to map shapes such as combustion chamber, intake manifolds or turbine blades accurately.

Self-similar collapse with cooling and heating in an expanding universe

OpenAIRE

Uchida, Shuji; Yoshida, Tatsuo

2003-01-01

We derive self-similar solutions including cooling and heating in an Einstein de-Sitter universe, and investigate the effects of cooling and heating on the gas density and temperature distributions. We assume that the cooling rate has a power-law dependence on the gas density and temperature, $\\Lambda$$\\propto$$\\rho^{A}T^{B}$, and the heating rate is $\\Gamma$$\\propto$$\\rho T$. The values of $A$ and $B$ are chosen by requiring that the cooling time is proportional to the Hubble time in order t...

Fretting fatigue cracking of a center guide bolt supporting the combustion chamber in a heavy-duty gas turbine engine

Energy Technology Data Exchange (ETDEWEB)

Neidel, Andreas; Fischer, Boromir; Gaedicke, Tobias [Siemens AG, Energy Sector, Gasturbinenwerk Berlin (Germany). Werkstoffprueflabor

2018-04-01

The slotted center guide bolt of the center guide feature of the lower part of the outer shell of an annular combustion chamber was found fractured in a heavy-duty gas turbine engine used for power generation, after approximately 5.500 operating hours. The incident was a one-off event and not a recurring incident. No similar events were reported from the fleet; hence the failure was not considered a field issue. The metallurgical root cause investigation that was ordered to determine the failure mechanism revealed that the incident center guide bolt failed by fretting fatigue cracking, a high cycle fatigue (HCF) phenomenon.

Real-time combustion control and diagnostics sensor-pressure oscillation monitor

Science.gov (United States)

Chorpening, Benjamin T [Morgantown, WV; Thornton, Jimmy [Morgantown, WV; Huckaby, E David [Morgantown, WV; Richards, George A [Morgantown, WV

2009-07-14

An apparatus and method for monitoring and controlling the combustion process in a combustion system to determine the amplitude and/or frequencies of dynamic pressure oscillations during combustion. An electrode in communication with the combustion system senses hydrocarbon ions and/or electrons produced by the combustion process and calibration apparatus calibrates the relationship between the standard deviation of the current in the electrode and the amplitudes of the dynamic pressure oscillations by applying a substantially constant voltage between the electrode and ground resulting in a current in the electrode and by varying one or more of (1) the flow rate of the fuel, (2) the flow rate of the oxidant, (3) the equivalence ratio, (4) the acoustic tuning of the combustion system, and (5) the fuel distribution in the combustion chamber such that the amplitudes of the dynamic pressure oscillations in the combustion chamber are calculated as a function of the standard deviation of the electrode current. Thereafter, the supply of fuel and/or oxidant is varied to modify the dynamic pressure oscillations.

The Multi-User Droplet Combustion Apparatus: the Development and Integration Concept for Droplet Combustion Payloads in the Fluids and Combustion Facility Combustion Integrated Rack

Science.gov (United States)

Myhre, C. A.

2002-01-01

The Multi-user Droplet Combustion Apparatus (MDCA) is a multi-user facility designed to accommodate four different droplet combustion science experiments. The MDCA will conduct experiments using the Combustion Integrated Rack (CIR) of the NASA Glenn Research Center's Fluids and Combustion Facility (FCF). The payload is planned for the International Space Station. The MDCA, in conjunction with the CIR, will allow for cost effective extended access to the microgravity environment, not possible on previous space flights. It is currently in the Engineering Model build phase with a planned flight launch with CIR in 2004. This paper provides an overview of the capabilities and development status of the MDCA. The MDCA contains the hardware and software required to conduct unique droplet combustion experiments in space. It consists of a Chamber Insert Assembly, an Avionics Package, and a multiple array of diagnostics. Its modular approach permits on-orbit changes for accommodating different fuels, fuel flow rates, soot sampling mechanisms, and varying droplet support and translation mechanisms to accommodate multiple investigations. Unique diagnostic measurement capabilities for each investigation are also provided. Additional hardware provided by the CIR facility includes the structural support, a combustion chamber, utilities for the avionics and diagnostic packages, and the fuel mixing capability for PI specific combustion chamber environments. Common diagnostics provided by the CIR will also be utilized by the MDCA. Single combustible fuel droplets of varying sizes, freely deployed or supported by a tether are planned for study using the MDCA. Such research supports how liquid-fuel-droplets ignite, spread, and extinguish under quiescent microgravity conditions. This understanding will help us develop more efficient energy production and propulsion systems on Earth and in space, deal better with combustion generated pollution, and address fire hazards associated with

Apparatus for incinerating hazardous waste

Science.gov (United States)

Chang, R.C.W.

1994-12-20

An apparatus is described for incinerating wastes, including an incinerator having a combustion chamber, a fluid-tight shell enclosing the combustion chamber, an afterburner, an off-gas particulate removal system and an emergency off-gas cooling system. The region between the inner surface of the shell and the outer surface of the combustion chamber forms a cavity. Air is supplied to the cavity and heated as it passes over the outer surface of the combustion chamber. Heated air is drawn from the cavity and mixed with fuel for input into the combustion chamber. The pressure in the cavity is maintained at least approximately 2.5 cm WC higher than the pressure in the combustion chamber. Gases cannot leak from the combustion chamber since the pressure outside the chamber (inside the cavity) is higher than the pressure inside the chamber. The apparatus can be used to treat any combustible wastes, including biological wastes, toxic materials, low level radioactive wastes, and mixed hazardous and low level transuranic wastes. 1 figure.

Thermal barrier coatings (TBC's) for high heat flux thrust chambers

Science.gov (United States)

Bradley, Christopher M.

The last 30 years materials engineers have been under continual pressure to develop materials with a greater temperature potential or to produce configurations that can be effectively cooled or otherwise protected at elevated temperature conditions. Turbines and thrust chambers produce some of the harshest service conditions for materials which lead to the challenges engineers face in order to increase the efficiencies of current technologies due to the energy crisis that the world is facing. The key tasks for the future of gas turbines are to increase overall efficiencies to meet energy demands of a growing world population and reduce the harmful emissions to protect the environment. Airfoils or blades tend to be the limiting factor when it comes to the performance of the turbine because of their complex design making them difficult to cool as well as limitations of their thermal properties. Key tasks for space transportation it to lower costs while increasing operational efficiency and reliability of our space launchers. The important factor to take into consideration is the rocket nozzle design. The design of the rocket nozzle or thrust chamber has to take into account many constraints including external loads, heat transfer, transients, and the fluid dynamics of expanded hot gases. Turbine engines can have increased efficiencies if the inlet temperature for combustion is higher, increased compressor capacity and lighter weight materials. In order to push for higher temperatures, engineers need to come up with a way to compensate for increased temperatures because material systems that are being used are either at or near their useful properties limit. Before thermal barrier coatings were applied to hot-section components, material alloy systems were able to withstand the service conditions necessary. But, with the increased demand for performance, higher temperatures and pressures have become too much for those alloy systems. Controlled chemistry of hot

Numerical investigation of CAI Combustion in the Opposed- Piston Engine with Direct and Indirect Water Injection

Science.gov (United States)

Pyszczek, R.; Mazuro, P.; Teodorczyk, A.

2016-09-01

This paper is focused on the CAI combustion control in a turbocharged 2-stroke Opposed-Piston (OP) engine. The barrel type OP engine arrangement is of particular interest for the authors because of its robust design, high mechanical efficiency and relatively easy incorporation of a Variable Compression Ratio (VCR). The other advantage of such design is that combustion chamber is formed between two moving pistons - there is no additional cylinder head to be cooled which directly results in an increased thermal efficiency. Furthermore, engine operation in a Controlled Auto-Ignition (CAI) mode at high compression ratios (CR) raises a possibility of reaching even higher efficiencies and very low emissions. In order to control CAI combustion such measures as VCR and water injection were considered for indirect ignition timing control. Numerical simulations of the scavenging and combustion processes were performed with the 3D CFD multipurpose AVL Fire solver. Numerous cases were calculated with different engine compression ratios and different amounts of directly and indirectly injected water. The influence of the VCR and water injection on the ignition timing and engine performance was determined and their application in the real engine was discussed.

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.

Increased combustion stability in modulating biomass boilers for district heating systems

Energy Technology Data Exchange (ETDEWEB)

Eriksson, Gunnar; Hermansson, Roger (eds.) [Lulea Univ. of Technology (Sweden)

2002-09-01

One of the problems in small district heating systems is the large load variation that must be handled by the system. If the boiler is designed to cover the needs during the coldest day in winter time in northern Europe it would have to run at loads as low as 10% of full load during summer time, when heat is needed only for tap water production. Load variations in small networks are quite fast and earlier investigations have shown that existing biomass boilers give rise to large amounts of harmful emissions at fast load variations and at low loads. The problem has been addressed in different ways: Three new boiler concepts have been realized and tested: A prototype of a 500 kW boiler with partitioned primary combustion chamber and supplied with a water heat store. A 10 kW bench scale combustor and a 500 kW prototype boiler based on pulsating combustion. Bench scale boilers to test the influence from applied sound on emissions and a 150 kW prototype boiler with a two-stage secondary vortex combustion chamber. Development of control and regulating equipment: Glow Guard, a control system using infra-red sensors to detect glowing char on the grate, has been constructed and tested. A fast prediction model that can be used in control systems has been developed. Simulation of the combustion process: Code to simulate pyrolysis/gasification of fuel on the grate has been developed. Combustion of the gas phase inside the combustion chamber has been simulated. The two models have been combined to describe the combustion process inside the primary chamber of a prototype boiler. A fast simulation code based on statistical methods that can predict the environmental performance of boilers has been developed. One of the boiler concepts matches the desired load span from 10 to 100% of full load with emissions far below the set limits for CO and THC and close to the set limits for NO{sub x}. The other boilers had a bit more narrow load range, one with very low emissions except for NO

Experimental research on combustion fluorine retention using calcium-based sorbents during coal combustion (II)

Energy Technology Data Exchange (ETDEWEB)

Qi, Q.; Ma, X.; Liu, J.; Wu, X.; Zhou, J.; Cen, K. [Liaoning Technical University, Fuxin (China). College of Resource and Environment Engineering

2008-12-15

Fluoride pollution produced by coal burning can be controlled with the calcium-based sorbent combustion fluorine technique in which calcium-based sorbents are mixed with the coal or sprayed into the combustion chamber. In a fixed bed tube furnace combustion experiment using one calcium-based natural mineral, limestone and one calcium-based building material, it was shown that the calcium-based sorbent particle grain size and pore structure have a big influence on the combustion fluorine retention effect. Reducing the calcium-based sorbent particle grain size and improving the calcium sorbent structure characteristics at very high temperature to enhance the fluorine retention effect is the important approach to the fluorine retention agent development. 8 refs., 1 fig., 5 tabs.

A novel split cycle internal combustion engine with integral waste heat recovery

International Nuclear Information System (INIS)

Dong, Guangyu; Morgan, Robert; Heikal, Morgan

2015-01-01

Highlights: • A novel engine thermodynamic cycle is proposed. • Theoretical analysis is applied to identify the key parameters of the thermodynamic cycle. • The key stages of the split cycle are analysed via one-dimensional modelling work. • The effecting mechanism of the split cycle efficiency is analysed. - Abstract: To achieve a step improvement in engine efficiency, a novel split cycle engine concept is proposed. The engine has separate compression and combustion cylinders and waste heat is recovered between the two. Quasi-isothermal compression of the charge air is realised in the compression cylinder while isobaric combustion of the air/fuel mixture is achieved in the combustion cylinder. Exhaust heat recovery between the compression and combustion chamber enables highly efficient recovery of waste heat within the cycle. Based on cycle analysis and a one-dimensional engine model, the fundamentals and the performance of the split thermodynamic cycle is estimated. Compared to conventional engines, the compression work can be significantly reduced through the injection of a controlled quantity of water in the compression cylinder, lowering the gas temperature during compression. Thermal energy can then be effectively recovered from the engine exhaust in a recuperator between the cooled compressor cylinder discharge air and the exhaust gas. The resulting hot high pressure air is then injected into a combustor cylinder and mixed with fuel, where near isobaric combustion leads to a low combustion temperature and reduced heat transferred from the cylinder wall. Detailed cycle simulation indicates a 32% efficiency improvement can be expected compared to the conventional diesel engines.

Narrow band flame emission from dieseline and diesel spray combustion in a constant volume combustion chamber

KAUST Repository

Wu, Zengyang

2016-08-18

In this paper, spray combustion of diesel (No. 2) and diesel-gasoline blend (dieseline: 80% diesel and 20% gasoline by volume) were investigated in an optically accessible constant volume combustion chamber. Effects of ambient conditions on flame emissions were studied. Ambient oxygen concentration was varied from 12% to 21% and three ambient temperatures were selected: 800 K, 1000 K and 1200 K. An intensified CCD camera coupled with bandpass filters was employed to capture the quasi-steady state flame emissions at 430 nm and 470 nm bands. Under non-sooting conditions, the narrow-band flame emissions at 430 nm and 470 nm can be used as indicators of CH∗ (methylidyne) and HCHO∗ (formaldehyde), respectively. The lift-off length was measured by imaging the OH∗ chemiluminescence at 310 nm. Flame emission structure and intensity distribution were compared between dieseline and diesel at wavelength bands. Flame emission images show that both narrow band emissions become shorter, thinner and stronger with higher oxygen concentration and higher ambient temperature for both fuels. Areas of weak intensity are observed at the flame periphery and the upstream for both fuels under all ambient conditions. Average flame emission intensity and area were calculated for 430 nm and 470 nm narrow-band emissions. At a lower ambient temperature the average intensity increases with increasing ambient oxygen concentration. However, at the 1200 K ambient temperature condition, the average intensity is not increasing monotonically for both fuels. For most of the conditions, diesel has a stronger average flame emission intensity than dieseline for the 430 nm band, and similar phenomena can be observed for the 470 nm band with 800 K and 1200 K ambient temperatures. However, for the 1000 K ambient temperature cases, dieseline has stronger average flame emission intensities than diesel for all oxygen concentrations at 470 nm band. Flame emissions for the two bands have a

Superheated fuel injection for combustion of liquid-solid slurries

Science.gov (United States)

Robben, F.A.

1984-10-19

A method and device are claimed for obtaining, upon injection, flash evaporation of a liquid in a slurry fuel to aid in ignition and combustion. The device is particularly beneficial for use of coal-water slurry fuels in internal combustion engines such as diesel engines and gas turbines, and in external combustion devices such as boilers and furnaces. The slurry fuel is heated under pressure to near critical temperature in an injector accumulator, where the pressure is sufficiently high to prevent boiling. After injection into a combustion chamber, the water temperature will be well above boiling point at a reduced pressure in the combustion chamber, and flash boiling will preferentially take place at solid-liquid surfaces, resulting in the shattering of water droplets and the subsequent separation of the water from coal particles. This prevents the agglomeration of the coal particles during the subsequent ignition and combustion process, and reduces the energy required to evaporate the water and to heat the coal particles to ignition temperature. The overall effect will be to accelerate the ignition and combustion rates, and to reduce the size of the ash particles formed from the coal. 2 figs., 2 tabs.

Core of a liquid-cooled nuclear reactor

International Nuclear Information System (INIS)

Wright, J.R.; McFall, A.

1975-01-01

The core of a liquid-cooled nuclear reactor, e.g. of a sodium-cooled fast reactor, is protected in such a way that the recoil wave resulting from loss of coolant in a cooling channel and caused by released gas is limited to a coolant inlet chamber of this cooling channel. The channels essentially consist of the coolant inlet chamber and a fuel chamber - with a fission gas storage plenum - through which the coolant flows. Between the two chambers, a locking device within a tube is provided offering a much larger flow resistance to the backflow of gas or coolant than in flow direction. The locking device may be a hydraulic countertorque control system, e.g. a valvular line. Other locking devices have got radially helical vanes running around an annular flow space. Furthermore, the locking device may consist of a number of needles running parallel to each other and forming a circular grid. Though it can be expanded by the forward flow - the needles are spreading - , it acts as a solid barrier for backflows. (TK) [de

Ozone Activated Cool Diffusion Flames of Butane Isomers in a Counterflow Facility

KAUST Repository

Al Omier, Abdullah Abdulaziz

2017-04-01

Proceeding from the aim to reduce global pollution emissions from the continuous burning of hydrocarbons stimulated by increasing energy demand, more efficient and ultra-low emissions’ combustion concepts such as the homogenous charge compression ignition engines (HCCI) have been developed. These new engines rely on the low temperature chemistry (LTC) combustion concept. A detailed investigation of the properties of cool flames, governed by LTC, is essential for the design of these new engines. The primary goal of this work was to build a fundamental counterflow experiment for cool flames studies in a diffusive system, to better understand combustion in LTC engines. The project was intended to provide a basic understanding of the low-temperature reactivity and cool flames properties of butane isomers under atmospheric pressure conditions. This was achieved by establishing self-sustaining cool flames through a novel technique of ozone addition to an oxygen stream in a non-premixed counterflow model. The ignition and extinction limits of butane isomers’ cool flames have been investigated under a variety of strain rates. Results revealed that establishment of cool flames are favored at lower strain rates. Iso-butane was less reactive than n-butane by showing higher ignition and extinction limits. Ozone addition showed a significant influence on cool flame ignition and sustenance; it was found that increasing ozone concentration in the oxidizer stream dramatically increased the reactivity of both fuels. Results showed increased fuel reactivity as the temperature of the fuel stream outlet increased. 4 A numerical analysis was performed to simulate ignition and extinction of the cool flame in diffusive systems. The results revealed that ignition and extinction limits of cool flames are predominantly governed by LTC. The model qualitatively captured experimental trends for both fuels; however, it overpredicted both ignition and extinction limits under all strain rates

Analysis of combustion turbine inlet air cooling systems applied to an operating cogeneration power plant

International Nuclear Information System (INIS)

Chacartegui, R.; Jimenez-Espadafor, F.; Sanchez, D.; Sanchez, T.

2008-01-01

In this work, combustion turbine inlet air cooling (CTIAC) systems are analyzed from an economic outlook, their effects on the global performance parameters and the economic results of the power plant. The study has been carried out on a combined cogeneration system, composed of a General Electric PG 6541 gas turbine and a heat recovery steam generator. The work has been divided into three parts. First, a revision of the present CTIAC technologies is shown, their effects on power plant performance and evaluation of the associated investment and maintenance costs. In a second phase of the work, the cogeneration plant was modelled with the objective of evaluating the power increase and the effects on the generated steam and the thermal oil. The cogeneration power plant model was developed, departing from the recorded operational data of the plant in 2005 and the gas turbine model offered by General Electric, to take into consideration that, in 2000, the gas turbine had been remodelled and the original performance curves should be corrected. The final objective of this model was to express the power plant main variables as a function of the gas turbine intake temperature, pressure and relative humidity. Finally, this model was applied to analyze the economic interest of different intake cooling systems, in different operative ranges and with different cooling capacities

Combustion performance evaluation of air staging of palm oil blends.

Science.gov (United States)

Mohd Jaafar, Mohammad Nazri; Eldrainy, Yehia A; Mat Ali, Muhammad Faiser; Wan Omar, W Z; Mohd Hizam, Mohd Faizi Arif

2012-02-21

The problems of global warming and the unstable price of petroleum oils have led to a race to develop environmentally friendly biofuels, such as palm oil or ethanol derived from corn and sugar cane. Biofuels are a potential replacement for fossil fuel, since they are renewable and environmentally friendly. This paper evaluates the combustion performance and emission characteristics of Refined, Bleached, and Deodorized Palm Oil (RBDPO)/diesel blends B5, B10, B15, B20, and B25 by volume, using an industrial oil burner with and without secondary air. Wall temperature profiles along the combustion chamber axis were measured using a series of thermocouples fitted axially on the combustion chamber wall, and emissions released were measured using a gas analyzer. The results show that RBDPO blend B25 produced the maximum emission reduction of 56.9% of CO, 74.7% of NOx, 68.5% of SO(2), and 77.5% of UHC compared to petroleum diesel, while air staging (secondary air) in most cases reduces the emissions further. However, increasing concentrations of RBDPO in the blends also reduced the energy released from the combustion. The maximum wall temperature reduction was 62.7% for B25 at the exit of the combustion chamber.

Gasdynamic modeling and parametric study of mesoscale internal combustion swing engine/generator systems

Science.gov (United States)

Gu, Yongxian

The demand of portable power generation systems for both domestic and military applications has driven the advances of mesoscale internal combustion engine systems. This dissertation was devoted to the gasdynamic modeling and parametric study of the mesoscale internal combustion swing engine/generator systems. First, the system-level thermodynamic modeling for the swing engine/generator systems has been developed. The system performance as well as the potentials of both two- and four-stroke swing engine systems has been investigated based on this model. Then through parameterc studies, the parameters that have significant impacts on the system performance have been identified, among which, the burn time and spark advance time are the critical factors related to combustion process. It is found that the shorter burn time leads to higher system efficiency and power output and the optimal spark advance time is about half of the burn time. Secondly, the turbulent combustion modeling based on levelset method (G-equation) has been implemented into the commercial software FLUENT. Thereafter, the turbulent flame propagation in a generic mesoscale combustion chamber and realistic swing engine chambers has been studied. It is found that, in mesoscale combustion engines, the burn time is dominated by the mean turbulent kinetic energy in the chamber. It is also shown that in a generic mesoscale combustion chamber, the burn time depends on the longest distance between the initial ignition kernel to its walls and by changing the ignition and injection locations, the burn time can be reduced by a factor of two. Furthermore, the studies of turbulent flame propagation in real swing engine chambers show that the combustion can be enhanced through in-chamber turbulence augmentation and with higher engine frequency, the burn time is shorter, which indicates that the in-chamber turbulence can be induced by the motion of moving components as well as the intake gas jet flow. The burn time

Analysis of the internal temperature of the combustion chamber of a compact system of co-generation; Analise das temperaturas internas da camara de combustao de um sistema compacto de co-geracao

Energy Technology Data Exchange (ETDEWEB)

Duarte, Joao B.F. [Universidade de Fortaleza (UNIFOR), CE (Brazil)], email: furlan@unifor.br; Couto, Heraldo S. [Instituto Nacional de Pesquisas Espaciais (INPE), Cachoeira Paulista, SP (Brazil)], email: heraldo@lcp.inpe.br; Holanda, Carlos A.M. de [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Engenharia Metalurgica e de Materiais], email: almir@metalmat.ufc.br

2008-07-01

Nowadays, the energy deficit represents one of the biggest governmental challenges, since there is still a great number of communities living in areas without electricity energy; and thus without access to electro-electronic equipment such as television, refrigerators, computers. The main focus of this work is to present the possibility of electricity energy generation in conjunction with the frozen or hot water production in for places without electricity transmission nets or even any type of alternative power plants. The system is based on the standard air cycle called Brayton cycle composed of a turbo-compressor model 4LGZ from BorgWarner, a combustion chamber, a power turbine, a heat exchanger, a water-ammonia chiller, a 5.0 kV A generator, and a command panel for automation and distribution of energy. This system that uses natural gas or LPG, will supply electric energy from the generator, hot water from the heat exchange with the gases of combustion, and water frozen from chiller using as the hot source the gases proceeding from the power system. The prototype is already being tested and the first results obtained are excellent. In this paper, we analyze the internal combustion chamber temperatures. (author)

Development of flameless combustion; Desarrollo de la combustion sin flama

Energy Technology Data Exchange (ETDEWEB)

Flores Sauceda, M. Leonardo; Cervantes de Gortari, Jaime Gonzalo [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: 8344afc@prodigy.net.mx; jgonzalo@servidor.unam.mx

2010-11-15

The paper intends contribute to global warming mitigation joint effort that develops technologies to capture the CO{sub 2} produced by fossil fuels combustion and to reduce emission of other greenhouse gases like the NO{sub x}. After reviewing existing combustion bibliography is pointed out that (a) touches only partial aspects of the collective system composed by Combustion-Heat transfer process-Environment, whose interactions are our primary interest and (b) most specialists think there is not yet a clearly winning technology for CO{sub 2} capture and storage. In this paper the study of combustion is focused as integrated in the aforementioned collective system where application of flameless combustion, using oxidant preheated in heat regenerators and fluent gas recirculation into combustion chamber plus appropriated heat and mass balances, simultaneously results in energy saving and environmental impact reduction. [Spanish] El trabajo pretende contribuir al esfuerzo conjunto de mitigacion del calentamiento global que aporta tecnologias para capturar el CO{sub 2} producido por la combustion de combustibles fosiles y para disminuir la emision de otros gases invernadero como NOx. De revision bibliografica sobre combustion se concluye que (a) trata aspectos parciales del sistema compuesto por combustion-proceso de trasferencia de calor-ambiente, cuyas interacciones son nuestro principal interes (b) la mayoria de especialistas considera no hay todavia una tecnologia claramente superior a las demas para captura y almacenaje de CO{sub 2}. Se estudia la combustion como parte integrante del mencionado sistema conjunto, donde la aplicacion de combustion sin flama, empleando oxidante precalentado mediante regeneradores de calor y recirculacion de gases efluentes ademas de los balances de masa y energia adecuados, permite tener simultaneamente ahorros energeticos e impacto ambiental reducido.

Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

Science.gov (United States)

Verma, V.; Barbot, L.; Filliatre, P.; Hellesen, C.; Jammes, C.; Svärd, S. Jacobsson

2017-07-01

Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment.

Method of calculating heat transfer in furnaces of small power

Directory of Open Access Journals (Sweden)

Khavanov Pavel

2016-01-01

Full Text Available This publication presents the experiences and results of generalization criterion equation of importance in the analysis of the processes of heat transfer and thermal calculations of low-power heat generators cooled combustion chambers. With generalizing depending estimated contribution of radiation and convective heat transfer component in the complex for the combustion chambers of small capacity boilers. Determined qualitative and quantitative dependence of the integrated radiative-convective heat transfer from the main factors working combustion chambers of small volume.

Numerical simulation of reacting and non-reacting flow in a combustion chamber; Numerisk simulering av reagerande och icke-reagerande stroemning i en braennkammare

Energy Technology Data Exchange (ETDEWEB)

Borg, A.; Revstedt, J.

1996-04-01

The purpose of this work has been to do a preliminary study of how well numerical calculations with different turbulence models can predict the flow and temperature fields of a strongly swirling and combusting flow in an experimental combustion chamber and to see which parameters in the mathematical model are the most important. The combustion chamber on which we have done the calculations is called Validation Rig II and was designed by Volvo Aero Corporation. The main part of the study has been carried out on a non-reacting flow but some work has also been done on reacting flow. In most cases it has not been meaningful to compare the calculations with the measurements because they differ quite a lot from each other. For the non-reacting case the following investigations have been made: * How the solution differs for different turbulence models, * The solutions sensitivity to inlet boundary conditions, * How different types of leakage disturb the flow, and * The difference in results between two different CFD-codes, the commercial code CFDS-Flow3D and a code developed at the department of fluid mechanics. For the reacting cases we have studied the influence of: * one or two reaction steps, * the effects of a change in reaction rate, * the influence of thermal radiation, and * the effects of changing the boundary conditions for temperature on the walls. The results from these calculations show that the inlet turbulence intensity has very little effect on the values of the turbulent quantities as well as the velocity profiles at the outlet. Changing the turbulence model or the outlet boundary conditions gives some change in velocity profiles at the outlet but only marginal effects on the swirl number. 21 refs, 54 figs, 19 tabs

Computational combustion and emission analysis of hydrogen-diesel blends with experimental verification

International Nuclear Information System (INIS)

Masood, M.; Ishrat, M.M.; Reddy, A.S.

2007-01-01

The paper discusses the effect of blending hydrogen with diesel in different proportions on combustion and emissions. A comparative study was carried out to analyze the effect of direct injection of hydrogen into the combustion chamber with that of induction through the inlet manifold for dual fueling. Percentage of hydrogen substitution varied from 20% to 80%, simultaneously reducing the diesel percentages. CFD analysis of dual fuel combustion and emissions were carried out for both the said methods using the CFD software FLUENT, meshing the combustion chamber was carried out using GAMBIT. The standard combustion and emission models were used in the analysis. In the second part of the paper, the effect of angle of injection in both the methods of hydrogen admission, on performance, combustion and emissions were analyzed. The experimental results were compared with that of simulated values and a good agreement between them was noticed. (author)

Combustor assembly for use in a turbine engine and methods of assembling same

Science.gov (United States)

Uhm, Jong Ho; Johnson, Thomas Edward

2013-05-14

A fuel nozzle assembly for use with a turbine engine is described herein. The fuel nozzle assembly includes a plurality of fuel nozzles positioned within an air plenum defined by a casing. Each of the plurality of fuel nozzles is coupled to a combustion liner defining a combustion chamber. Each of the plurality of fuel nozzles includes a housing that includes an inner surface that defines a cooling fluid plenum and a fuel plenum therein, and a plurality of mixing tubes extending through the housing. Each of the mixing tubes includes an inner surface defining a flow channel extending between the air plenum and the combustion chamber. At least one mixing tube of the plurality of mixing tubes including at least one cooling fluid aperture for channeling a flow of cooling fluid from the cooling fluid plenum to the flow channel.

Furnace for degasification and gasification of combustibles rich in ashes

Energy Technology Data Exchange (ETDEWEB)

1952-05-13

A furnace is described for the degasification and the gasification of combustibles rich in ashes with continuous-functioning vertical chambers of transversal rectangular sections in which the washing gas flows from one side to the other, traversing the combustible, characterized by the fact that the height of the combustible surrounded by the washing gas stays in a proportion higher than 10:1 to the thickness of the width of combustible.

Combustion flame-plasma hybrid reactor systems, and chemical reactant sources

Science.gov (United States)

Kong, Peter C

2013-11-26

Combustion flame-plasma hybrid reactor systems, chemical reactant sources, and related methods are disclosed. In one embodiment, a combustion flame-plasma hybrid reactor system comprising a reaction chamber, a combustion torch positioned to direct a flame into the reaction chamber, and one or more reactant feed assemblies configured to electrically energize at least one electrically conductive solid reactant structure to form a plasma and feed each electrically conductive solid reactant structure into the plasma to form at least one product is disclosed. In an additional embodiment, a chemical reactant source for a combustion flame-plasma hybrid reactor comprising an elongated electrically conductive reactant structure consisting essentially of at least one chemical reactant is disclosed. In further embodiments, methods of forming a chemical reactant source and methods of chemically converting at least one reactant into at least one product are disclosed.

Combustion physics

Science.gov (United States)

Jones, A. R.

1985-11-01

Over 90% of our energy comes from combustion. By the year 2000 the figure will still be 80%, even allowing for nuclear and alternative energy sources. There are many familiar examples of combustion use, both domestic and industrial. These range from the Bunsen burner to large flares, from small combustion chambers, such as those in car engines, to industrial furnaces for steel manufacture or the generation of megawatts of electricity. There are also fires and explosions. The bountiful energy release from combustion, however, brings its problems, prominent among which are diminishing fuel resources and pollution. Combustion science is directed towards finding ways of improving efficiency and reducing pollution. One may ask, since combustion is a chemical reaction, why physics is involved: the answer is in three parts. First, chemicals cannot react unless they come together. In most flames the fuel and air are initially separate. The chemical reaction in the gas phase is very fast compared with the rate of mixing. Thus, once the fuel and air are mixed the reaction can be considered to occur instantaneously and fluid mechanics limits the rate of burning. Secondly, thermodynamics and heat transfer determine the thermal properties of the combustion products. Heat transfer also plays a role by preheating the reactants and is essential to extracting useful work. Fluid mechanics is relevant if work is to be performed directly, as in a turbine. Finally, physical methods, including electric probes, acoustics, optics, spectroscopy and pyrometry, are used to examine flames. The article is concerned mainly with how physics is used to improve the efficiency of combustion.

An Experimental Investigation of Self-Excited Combustion Dynamics in a Single Element Lean Direct Injection (LDI) Combustor

Science.gov (United States)

Gejji, Rohan M.

The management of combustion dynamics in gas turbine combustors has become more challenging as strict NOx/CO emission standards have led to engine operation in a narrow, lean regime. While premixed or partially premixed combustor configurations such as the Lean Premixed Pre-vaporized (LPP), Rich Quench Lean burn (RQL), and Lean Direct Injection (LDI) have shown a potential for reduced NOx emissions, they promote a coupling between acoustics, hydrodynamics and combustion that can lead to combustion instabilities. These couplings can be quite complex, and their detailed understanding is a pre-requisite to any engine development program and for the development of predictive capability for combustion instabilities through high-fidelity models. The overarching goal of this project is to assess the capability of high-fidelity simulation to predict combustion dynamics in low-emissions gas turbine combustors. A prototypical lean-direct-inject combustor was designed in a modular configuration so that a suitable geometry could be found by test. The combustor comprised a variable length air plenum and combustion chamber, air swirler, and fuel nozzle located inside a subsonic venturi. The venturi cross section and the fuel nozzle were consistent with previous studies. Test pressure was 1 MPa and variables included geometry and acoustic resonance, inlet temperatures, equivalence ratio, and type of liquid fuel. High-frequency pressure measurements in a well-instrumented metal chamber yielded frequencies and mode shapes as a function of inlet air temperature, equivalence ratio, fuel nozzle placement, and combustor acoustic resonances. The parametric survey was a significant effort, with over 105 tests on eight geometric configurations. A good dataset was obtained that could be used for both operating-point-dependent quantitative comparisons, and testing the ability of the simulation to predict more global trends. Results showed a very strong dependence of instability amplitude on

Analysis of knocking combustion with the aid of pressure sensors; Einsatz von Drucksensoren zur Beurteilung klopfender Verbrennung

Energy Technology Data Exchange (ETDEWEB)

Stadler, J.; Walter, T. [Kistler AG, Winterthur (Switzerland); Bertola, A.; Wolfer, P.; Hoewing, J. [Kistler Instrumente GmbH, Ostfildern (Germany); Gossweiler, C. [Fachhochschule Nordwestschweiz (Switzerland). ITFE; Rothe, M.; Spicher, U. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Kolbenmaschinen

2006-07-01

Depending on its frequency and intensity, knocking combustion can cause engine damage due to excessive thermal or mechanical stress on components. During knocking combustion, the cylinder pressure signal is overlaid with high-frequency pressure oscillations. Reliable detection of the knock timing and quantification of the knock intensity based on local measurement of the cylinder pressure demand for particular care, especially when it comes to selecting and adapting the sensor technology and also during the evaluation process using customary knock analysis methods. This publication examines various types of cylinder pressure sensors, how they are installed in the combustion chamber, the effect of sensor positioning and assesses them with regard to accuracy. Finally, on the basis of the test results, recommendations are given for selecting sensors and adapting them within the combustion chamber. A crucial factor for pressure measurement during knocking combustion is the sensor position within the combustion chamber. The sensor type is of secondary importance; at most, cavities between the combustion chamber and the sensor may influence the measuring signal. To assess the sensitivity of the knock evaluation algorithms to various mounting positions and sensor types, it is advisable to carry out comparative measurements between different sensor positions and the measuring spark plug. (orig.)

Barium fluoride crystals and self-quenching streamer chambers as a position sensitive gamma-ray detector

International Nuclear Information System (INIS)

Salomon, M.; DeMooy, S.; Ruggier, L.

1985-01-01

We have studied the possibility of using selfquenching streamer chambers to detect photoelectrons produced by a photoconverter in conjunction with Barium Fluoride scintillators. With the purpose to obtain a high efficiency detector, we attempted to combine a BaF 2 scintillator with a gas chamber operating at large electric fields and a high fraction of quenching gas like self-quenching streamer (SQS) chamber, as the electric fields at the cathode could be made larger than in the proportional mode. Furthermore, previous results indicated that in this mode, part of the large amplification was obtained through strong absorption of uv photons near the anode

Effects of Port Shape on Steady Flow Characteristics in an SI Engine with Semi-Wedge Combustion Chamber (2) - Velocity Distribution (2)

Energy Technology Data Exchange (ETDEWEB)

Yoon, Inkyoung; Ohm, Inyong [Seoul Nat’l Univ. of Science and Technology, Seoul (Korea, Republic of)

2017-02-15

This study is the second investigation on the steady flow characteristics of an SI engine with a semi-edge combustion chamber as a function of the port shape with varying evaluation positions. For this purpose, the planar velocity profiles were measured from 1.75B, 1.75 times of bore position apart from the bottom of head, to 6.00B positions using particle – image velocimetry. The flow patterns were examined with both a straight and a helical port. The velocity profiles, streamlines, and centers of swirl were almost the same at the same valve lift regardless of the measuring position, which is quite different from the case of the pent-roof combustion chamber. All the eccentricity values of the straight port were out of distortion criterion 0.15 through the lifts and the position. However, the values of the helical port exceeded the distortion criterion by up to 4 mm lift, but decreased rapidly above the 3.00B position and the 5 mm lift. There always existed a relative offset effect in the evaluation of the swirl coefficient using the PIV method due to the difference of the ideal impulse swirl meter velocity profile assumption, except for the cylinder-center-base estimation that was below 4 mm of the straight port. Finally, it was concluded that taking the center as an evaluation basis and the assumption about the axial velocity profile did not have any qualitative effect on swirl evaluation, but affected the value owing to the detailed profile.

Optimization of combustion process for radiation-treated solid fuels in dust state

International Nuclear Information System (INIS)

Askarova, A.S.; Bajdullaeva, G.E.

1997-01-01

Computation experiment on combustion of solid radiation-treated fuel in burning chamber of boiler at Pavlodar thermal electric plant is carried out. Velocity, temperature distribution and concentration of combustion products by height of chamber are received. Analysis of received results shows that radiation treatment of fuels exerts substantial effect on egress parameters of thermal electric plant. It is shown, that radiation treatment allows to improve effectiveness of boiler device and reduce of harmful substances discharge in atmosphere. Results of conducted numerical experiments allow to create complete methods of solid fuel combustion with high moisture and ashiness

Small-scale, self-propagating combustion realized with on-chip porous silicon.

Science.gov (United States)

Piekiel, Nicholas W; Morris, Christopher J

2015-05-13

For small-scale energy applications, energetic materials represent a high energy density source that, in certain cases, can be accessed with a very small amount of energy input. Recent advances in microprocessing techniques allow for the implementation of a porous silicon energetic material onto a crystalline silicon wafer at the microscale; however, combustion at a small length scale remains to be fully investigated, particularly with regards to the limitations of increased relative heat loss during combustion. The present study explores the critical dimensions of an on-chip porous silicon energetic material (porous silicon + sodium perchlorate (NaClO4)) required to propagate combustion. We etched ∼97 μm wide and ∼45 μm deep porous silicon channels that burned at a steady rate of 4.6 m/s, remaining steady across 90° changes in direction. In an effort to minimize the potential on-chip footprint for energetic porous silicon, we also explored the minimum spacing between porous silicon channels. We demonstrated independent burning of porous silicon channels at a spacing of 0.5 m on a chip surface area of 1.65 cm(2). Smaller porous silicon channels of ∼28 μm wide and ∼14 μm deep were also utilized. These samples propagated combustion, but at times, did so unsteadily. This result may suggest that we are approaching a critical length scale for self-propagating combustion in a porous silicon energetic material.

Emergency reactor container cooling facility

International Nuclear Information System (INIS)

Suzuki, Hiroaki; Matsumoto, Tomoyuki.

1992-01-01

The present invention concerns an emergency cooling facility for a nuclear reactor container having a pressure suppression chamber, in which water in the suppression chamber is effectively used for cooling the reactor container. That is, the lower portion of a water pool in the pressure suppression chamber and the inside of the reactor container are connected by a pipeline. The lower end of the pipeline and a pressurized incombustible gas tank disposed to the outside of the reactor container are connected by a pipeline by way of valves. Then, when the temperature of the lower end of the pressure vessel exceeds a predetermined value, the valves are opened. If the valves are opened, the incombustible gas flows into the lower end of the pipeline connecting the lower portion of the water pool in the pressure suppression chamber and the inside of the reactor container. Since the inside of the pipeline is a two phase flow comprising a mixture of a gas phase and a liquid phase, the average density is decreased. Therefore, the water level of the two phase flow is risen by the level difference between the inside and the outside of the pipeline and, finally, the two phase mixture is released into the reactor container. As a result, the reactor container can be cooled by water in the suppression chamber by a static means without requiring pumps. (I.S.)

SO2 emission reducing by Ca(OH)2 using at combustion of coal from East-Maritsa basin

International Nuclear Information System (INIS)

Batov, S.; Gadzhanov, P.; Popov, D.; Panchev, T.; Mikhajlov, Ya.; Shushulov, D.; Grozev, A.

1997-01-01

The 'Maritsa-Iztok' coal field contains about 65% of the lignite and 57% of the Bulgarian coal resources.The 'Maritsa-Iztok' lignite coal have a low combustion temperature and high concentration of ashes, moisture and sulfur. The concentration of sulphur oxides emitted is about 800 000 t per year, which is among the highest concentrations for Europe. In order to reduce the sulphur concentration, theoretical and experimental studies have been performed. A determination of the efficiency of some new methods for SO 2 reduction has been done. In this paper the results from experiments using Ca(OH) 2 as reagent, are presented. The experimental facility is a non-cooled combustion chamber which provides the same conditions as in the lignite coal boilers. In the experiments ground and dried lignite coal have been used. The controlled values are O 2 , CO, NO x , SO 2 , as well as the temperature of the hot and cold air and the combustion products after the cooler and absorber. Four different technologies have been performed. The first is adding of Ca(OH) 2 which give about 30% maximal SO 2 reducing for grain size 45μm and Ca/S=1.6. The obtaining of this small size is now difficult. The second technology is introduction of Ca(OH) 2 in the combustion chamber at a temperature 900-1050 o C. The cleaning efficiency is about 48.5% for the optimal concentration of the additive. As a washing of the combustion product with water in the absorber after the desulfurization. The second phase give 20% additional cleaning. Thus the total cleaning effect is 65-70%. The third method used lime washing of the combustion products. For the Bulgarian coal with a great S content it is the most suitable method. It gives a SO 2 cleaning up to 95%. Lime wash with pH=12.3 has been used with various amounts of the reagent. Experiments with different amounts of lime wash and different quality of the coal are performed and the specific reagent consumption has been determined

Spray combustion of biomass-based renewable diesel fuel using multiple injection strategy in a constant volume combustion chamber

KAUST Repository

Jing, Wei; Wu, Zengyang; Roberts, William L.; Fang, Tiegang

2016-01-01

Effect of a two-injection strategy associated with a pilot injection on the spray combustion process was investigated under conventional diesel combustion conditions (1000 K and 21% O2 concentration) for a biomass-based renewable diesel fuel, i

Efficient energy recovering air inlet system for an internal combustion engine

NARCIS (Netherlands)

2011-01-01

An air inlet system (10) for an internal combustion engine (200) is provided. The air inlet system comprises an air intake port (20), an air output port (30) for providing air for a combustion chamber (202) of the combustion engine (200), and a turbine (40). The turbine (40) is situated in between

Efficient energy recovering air inlet system for an international combustion engine

NARCIS (Netherlands)

2013-01-01

An air inlet system (10) for an internal combustion engine (200) is provided. The air inlet system comprises an air intake port (20), an air output port (30) for providing air for a combustion chamber (202) of the combustion engine (200), and a turbine (40). The turbine (40) is situated in between

Flow and Combustion in Advanced Gas Turbine Combustors

CERN Document Server

Janicka, Johannes; Schäfer, Michael; Heeger, Christof

2013-01-01

With regard to both the environmental sustainability and operating efficiency demands, modern combustion research has to face two main objectives, the optimization of combustion efficiency and the reduction of pollutants. This book reports on the combustion research activities carried out within the Collaborative Research Center (SFB) 568 “Flow and Combustion in Future Gas Turbine Combustion Chambers” funded by the German Research Foundation (DFG). This aimed at designing a completely integrated modeling and numerical simulation of the occurring very complex, coupled and interacting physico-chemical processes, such as turbulent heat and mass transport, single or multi-phase flows phenomena, chemical reactions/combustion and radiation, able to support the development of advanced gas turbine chamber concepts.

Global cloud condensation nuclei influenced by carbonaceous combustion aerosol

Directory of Open Access Journals (Sweden)

D. V. Spracklen

2011-09-01

Full Text Available Black carbon in carbonaceous combustion aerosol warms the climate by absorbing solar radiation, meaning reductions in black carbon emissions are often perceived as an attractive global warming mitigation option. However, carbonaceous combustion aerosol can also act as cloud condensation nuclei (CCN so they also cool the climate by increasing cloud albedo. The net radiative effect of carbonaceous combustion aerosol is uncertain because their contribution to CCN has not been evaluated on the global scale. By combining extensive observations of CCN concentrations with the GLOMAP global aerosol model, we find that the model is biased low (normalised mean bias = −77 % unless carbonaceous combustion aerosol act as CCN. We show that carbonaceous combustion aerosol accounts for more than half (52–64 % of global CCN with the range due to uncertainty in the emitted size distribution of carbonaceous combustion particles. The model predicts that wildfire and pollution (fossil fuel and biofuel carbonaceous combustion aerosol causes a global mean cloud albedo aerosol indirect effect of −0.34 W m⁻², with stronger cooling if we assume smaller particle emission size. We calculate that carbonaceous combustion aerosol from pollution sources cause a global mean aerosol indirect effect of −0.23 W m⁻². The small size of carbonaceous combustion particles from fossil fuel sources means that whilst pollution sources account for only one-third of the emitted mass they cause two-thirds of the cloud albedo aerosol indirect effect that is due to carbonaceous combustion aerosol. This cooling effect must be accounted for, along with other cloud effects not studied here, to ensure that black carbon emissions controls that reduce the high number concentrations of fossil fuel particles have the desired net effect on climate.

Combustible structural composites and methods of forming combustible structural composites

Science.gov (United States)

Daniels, Michael A.; Heaps, Ronald J.; Steffler, Eric D.; Swank, W. David

2013-04-02

Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

Cooled airfoil in a turbine engine

Science.gov (United States)

Vitt, Paul H; Kemp, David A; Lee, Ching-Pang; Marra, John J

2015-04-21

An airfoil in a gas turbine engine includes an outer wall and an inner wall. The outer wall includes a leading edge, a trailing edge opposed from the leading edge in a chordal direction, a pressure side, and a suction side. The inner wall is coupled to the outer wall at a single chordal location and includes portions spaced from the pressure and suction sides of the outer wall so as to form first and second gaps between the inner wall and the respective pressure and suction sides. The inner wall defines a chamber therein and includes openings that provide fluid communication between the respective gaps and the chamber. The gaps receive cooling fluid that provides cooling to the outer wall as it flows through the gaps. The cooling fluid, after traversing at least substantial portions of the gaps, passes into the chamber through the openings in the inner wall.

System and method for reducing combustion dynamics in a combustor

Science.gov (United States)

Uhm, Jong Ho; Johnson, Thomas Edward; Zuo, Baifang; York, William David

2013-08-20

A system for reducing combustion dynamics in a combustor includes an end cap having an upstream surface axially separated from a downstream surface, and tube bundles extend through the end cap. A diluent supply in fluid communication with the end cap provides diluent flow to the end cap. Diluent distributors circumferentially arranged inside at least one tube bundle extend downstream from the downstream surface and provide fluid communication for the diluent flow through the end cap. A method for reducing combustion dynamics in a combustor includes flowing fuel through tube bundles that extend axially through an end cap, flowing a diluent through diluent distributors into a combustion chamber, wherein the diluent distributors are circumferentially arranged inside at least one tube bundle and each diluent distributor extends downstream from the end cap, and forming a diluent barrier in the combustion chamber between at least one pair of adjacent tube bundles.

New type of microengine using internal combustion of hydrogen and oxygen

Science.gov (United States)

Svetovoy, Vitaly B.; Sanders, Remco G. P.; Ma, Kechun; Elwenspoek, Miko C.

2014-01-01

Microsystems become part of everyday life but their application is restricted by lack of strong and fast motors (actuators) converting energy into motion. For example, widespread internal combustion engines cannot be scaled down because combustion reactions are quenched in a small space. Here we present an actuator with the dimensions 100 × 100 × 5 μm3 that is using internal combustion of hydrogen and oxygen as part of its working cycle. Water electrolysis driven by short voltage pulses creates an extra pressure of 0.5–4 bar for a time of 100–400 μs in a chamber closed by a flexible membrane. When the pulses are switched off this pressure is released even faster allowing production of mechanical work in short cycles. We provide arguments that this unexpectedly fast pressure decrease is due to spontaneous combustion of the gases in the chamber. This actuator is the first step to truly microscopic combustion engines. PMID:24599052

New type of microengine using internal combustion of hydrogen and oxygen.

Science.gov (United States)

Svetovoy, Vitaly B; Sanders, Remco G P; Ma, Kechun; Elwenspoek, Miko C

2014-03-06

Microsystems become part of everyday life but their application is restricted by lack of strong and fast motors (actuators) converting energy into motion. For example, widespread internal combustion engines cannot be scaled down because combustion reactions are quenched in a small space. Here we present an actuator with the dimensions 100 × 100 × 5 μm(3) that is using internal combustion of hydrogen and oxygen as part of its working cycle. Water electrolysis driven by short voltage pulses creates an extra pressure of 0.5-4 bar for a time of 100-400 μs in a chamber closed by a flexible membrane. When the pulses are switched off this pressure is released even faster allowing production of mechanical work in short cycles. We provide arguments that this unexpectedly fast pressure decrease is due to spontaneous combustion of the gases in the chamber. This actuator is the first step to truly microscopic combustion engines.

Air fuel ratio detector corrector for combustion engines using adaptive neurofuzzy networks

Directory of Open Access Journals (Sweden)

Nidhi Arora

2013-07-01

Full Text Available A perfect mix of the air and fuel in internal combustion engines is desirable for proper combustion of fuel with air. The vehicles running on road emit harmful gases due to improper combustion. This problem is severe in heavy vehicles like locomotive engines. To overcome this problem, generally an operator opens or closes the valve of fuel injection pump of locomotive engines to control amount of air going inside the combustion chamber, which requires constant monitoring. A model is proposed in this paper to alleviate combustion process. The method involves recording the time-varying flow of fuel components in combustion chamber. A Fuzzy Neural Network is trained for around 40 fuels to ascertain the required amount of air to form a standard mix to produce non-harmful gases and about 12 fuels are used for testing the network’s performance. The network then adaptively determines the additional/subtractive amount of air required for proper combustion. Mean square error calculation ensures the effectiveness of the network’s performance.

Strong Electron Self-Cooling in the Cold-Electron Bolometers Designed for CMB Measurements

Science.gov (United States)

Kuzmin, L. S.; Pankratov, A. L.; Gordeeva, A. V.; Zbrozhek, V. O.; Revin, L. S.; Shamporov, V. A.; Masi, S.; de Bernardis, P.

2018-03-01

We have realized cold-electron bolometers (CEB) with direct electron self-cooling of the nanoabsorber by SIN (Superconductor-Insulator-Normal metal) tunnel junctions. This electron self-cooling acts as a strong negative electrothermal feedback, improving noise and dynamic properties. Due to this cooling the photon-noise-limited operation of CEBs was realized in array of bolometers developed for the 345 GHz channel of the OLIMPO Balloon Telescope in the power range from 10 pW to 20 pW at phonon temperature Tph =310 mK. The negative electrothermal feedback in CEB is analogous to TES but instead of artificial heating we use cooling of the absorber. The high efficiency of the electron self-cooling to Te =100 mK without power load and to Te=160 mK under power load is achieved by: - a very small volume of the nanoabsorber (0.02 μm3) and a large area of the SIN tunnel junctions, - effective removal of hot quasiparticles by arranging double stock at both sides of the junctions and close position of the normal metal traps, - self-protection of the 2D array of CEBs against interferences by dividing them between N series CEBs (for voltage interferences) and M parallel CEBs (for current interferences), - suppression of Andreev reflection by a thin layer of Fe in the AlFe absorber. As a result even under high power load the CEBs are working at electron temperature Te less than Tph . To our knowledge, there is no analogue in the bolometers technology in the world for bolometers working at electron temperature colder than phonon temperature.

Detailed Measurement of ORSC Main Chamber Injector Dynamics

Science.gov (United States)

Bedard, Michael J.

Improving fidelity in simulation of combustion dynamics in rocket combustors requires an increase in experimental measurement fidelity for validation. In a model rocket combustor, a chemiluminescence based spectroscopy technique was used to capture flame light emissions for direct comparison to a computational simulation of the production of chemiluminescent species. The comparison indicated that high fidelity models of rocket combustors can predict spatio-temporal distribution of chemiluminescent species with trend-wise accuracy. The comparison also indicated the limited ability of OH* and CH* emission to indicate flame heat release. Based on initial spectroscopy experiments, a photomultiplier based chemiluminescence sensor was designed to increase the temporal resolution of flame emission measurements. To apply developed methodologies, an experiment was designed to investigate the flow and combustion dynamics associated with main chamber injector elements typical of the RD-170 rocket engine. A unique feature of the RD-170 injector element is the beveled expansion between the injector recess and combustion chamber. To investigate effects of this geometry, a scaling methodology was applied to increase the physical scale of a single injector element while maintaining traceability to the RD-170 design. Two injector configurations were tested, one including a beveled injector face and the other a flat injector face. This design enabled improved spatial resolution of pressure and light emission measurements densely arranged in the injector recess and near-injector region of the chamber. Experimental boundary conditions were designed to closely replicate boundary conditions in simulations. Experimental results showed that the beveled injector face had a damping effect on pressure fluctuations occurring near the longitudinal resonant acoustic modes of the chamber, implying a mechanism for improved overall combustion stability. Near the injector, the beveled geometry

Direct synthesis of La9.33Si6O26 ultrafine powder via sol-gel self-combustion method

International Nuclear Information System (INIS)

Tian Changan; Liu Junliang; Cai Jun; Zeng Yanwei

2008-01-01

Single phase La 9.33 Si 6 O 26 ultrafine powder, as a kind of highly activated precursor to prepare medium-to-low temperature electrolyte for solid oxide fuel cells (SOFCs), has been successfully synthesized via a non-aqueous sol-gel and self-combustion approach from the starting materials: lanthanum nitrate (La(NO 3 ) 3 .6H 2 O), citric acid, ethylene glycol (EG), tetraethyl orthosilicate (TEOS) and ammonium nitrate. The details of gel's self-combustion were investigated by DTA-TG and the structural characterization of as-synthesized powder from self-combustion was performed by XRD and SEM. The results show that La 9.33 Si 6 O 26 single phase of apatite-type crystal structure can be directly synthesized by sol-gel self-combustion method without further calcinations on the condition that the molar ratio (R) of NO 3 - to citric acid and ethylene glycol being 6:1. Such powders composed of well-dispersed particles with an average size of 200 nm and a specific surface area of 5.54 m 2 /g. It can be sintered to 90% of its theoretical density at 1500 deg. C for 10 h, about 200 deg. C lower than the sintering temperature for the powder derived from traditional solid reactions. The sintered material has a thermal expansion coefficient of 9.2 x 10 -6 K -1 between room temperature and 800 deg. C

Relativistic Turbulence with Strong Synchrotron and Synchrotron-Self-Compton Cooling

Science.gov (United States)

Uzdensky, D. A.

2018-03-01

Many relativistic plasma environments in high-energy astrophysics, including pulsar wind nebulae, hot accretion flows onto black holes, relativistic jets in active galactic nuclei and gamma-ray bursts, and giant radio lobes, are naturally turbulent. The plasma in these environments is often so hot that synchrotron and inverse-Compton (IC) radiative cooling becomes important. In this paper we investigate the general thermodynamic and radiative properties (and hence the observational appearance) of an optically thin relativistically hot plasma stirred by driven magnetohydrodynamic (MHD) turbulence and cooled by radiation. We find that if the system reaches a statistical equilibrium where turbulent heating is balanced by radiative cooling, the effective electron temperature tends to attain a universal value θ = kT_e/m_e c^2 ˜ 1/√{τ_T}, where τT = neσTL ≪ 1 is the system's Thomson optical depth, essentially independent of the strength of turbulent driving and hence of the magnetic field. This is because both MHD turbulent dissipation and synchrotron cooling are proportional to the magnetic energy density. We also find that synchrotron self-Compton (SSC) cooling and perhaps a few higher-order IC components are automatically comparable to synchrotron in this regime. The overall broadband radiation spectrum then consists of several distinct components (synchrotron, SSC, etc.), well separated in photon energy (by a factor ˜ τ_T^{-1}) and roughly equal in power. The number of IC peaks is checked by Klein-Nishina effects and depends logarithmically on τT and the magnetic field. We also examine the limitations due to synchrotron self-absorption, explore applications to Crab PWN and blazar jets, and discuss links to radiative magnetic reconnection.

Laboratory study on the cooling effect of flash water evaporative cooling technology for ventilation and air-conditioning of buildings

DEFF Research Database (Denmark)

Fang, Lei; Yuan, Shu; Yang, Jianrong

environments and the other simulated an air-conditioned indoor environment. The flash water evaporation cooling device was installed in the chamber that simulated indoor environment. The air from the chamber simulating outdoor environment was introduced into the cooling device and cooled by the flash water......, is effective for ventilation and air-conditioning in warm/hot and dry climate zones. The technology can provide fresh outdoor air with a temperature of 4 to 7 °C lower than room air temperature.......This paper presents a simple cooling technology using flash water evaporation. The technology combines a water atomizer with a plate heat exchanger used for heat recovery of a ventilation system. It is mainly used to cool the ventilation airflow from outdoors and is particularly suitable to be used...

Ionization chamber for smoke detector and the like

International Nuclear Information System (INIS)

Rork, G.D.; Thorp, E.J.; Zegarski, R.J.

1985-01-01

This invention relates to detectors of the ionization type for detecting airborne particulate matter and, in particular, to the construction of an ionization chamber for such a detector. This invention may be used for detecting a variety of materials, such as dust, fog and the like, but is particularly useful for detecting combustion products such as smoke. The smoke detector ionization chamber has two electrodes connected to a source of electric power; means defining access openings for enabling air flow into and out of the chamber; and means for causing ionization within the chamber. It has control structure means within the chamber in the path of the airflow cooperating with the electrodes to establish within the chamber an electric field having a higher intensity close to the access openings and a lower intensity in the remainder of the chamber without significantly impairing the flow of neutral particles into the chamber. The control structure reduces airflow velocity within the chamber without adversely affecting the access of airborne particles to the chamber

Vertex chamber for the KEDR detector

International Nuclear Information System (INIS)

Aulchenko, V.M.; Chilingarov, A.G.; Kolachev, G.M.; Lazarenko, O.B.; Nagaslaev, V.P.; Romanov, L.V.

1989-01-01

The project and design of the vertex chamber for the KEDR detector is described. The chamber consists of 6 cylindrical layers of tubes with 10 mm diameter and 800 mm length. The tubes are made of 20 μm thick aluminized mylar. The prototype tests show that it is possible to achieve a resolution of 20-30 μm using the cool gas mixtures. (orig.)

Dilution refrigeration with multiple mixing chambers

International Nuclear Information System (INIS)

Coops, G.M.

1981-01-01

A dilution refrigerator is an instrument to reach temperatures in the mK region in a continuous way. The temperature range can be extended and the cooling power can be enlarged by adding an extra mixing chamber. In this way we obtain a double mixing chamber system. In this thesis the theory of the multiple mixing chamber is presented and tested on its validity by comparison with the measurements. Measurements on a dilution refrigerator with a circulation rate up to 2.5 mmol/s are also reported. (Auth.)

Transient Heat Transfer Properties in a Pulse Detonation Combustor

Science.gov (United States)

2011-03-01

appreciation to my wife Shelly , and my sons Cody, Brandon, and Tyler for their encouragement, support, and understanding during this challenging time...operation frequencies. 56 B. FUTURE WORK A redesign of the cooled combustor chamber is currently in progress and will result in a cast mold. A...water-cooled combustor with casted swept ramps in the combustion chamber that are cooled as well maximizes the amount cooling to the ramps to help

Combustion characteristics of the LO2/GCH4 fuel-rich preburners for staged combustion cycle rocket engines

Science.gov (United States)

Ono, Fumiei; Tamura, Hiroshi; Sakamoto, Hiroshi; Sasaki, Masaki

1991-09-01

The combustion characteristics of Liquid Oxygen (LO2)/Gaseous Methane (GCH4) fuel rich preburners were experimentally studied using subscale hardware. Three types of preburners with coaxial type propellant injection elements were designed and fabricated, and were used for hot fire testing. LO2 was used as oxidizer, and GCH4 at room temperature was used as fuel. The tests were conducted at chamber pressures ranging from 6.7 to 11.9 M Pa, and oxidizer to fuel ratios ranged from 0.16 to 0.42. The test results, which include combustion gas temperature T(sub c), characteristic velocity C(sup *) and soot adhesion data, are presented. The T(sub c) efficiency and the C(sup *) efficiency were found to be a function of oxidizer to fuel ratio and chamber pressure. These efficiencies are correlated by an empirical correlation parameter which accounts for the effects of oxidizer to fuel ratio and chamber pressure. The exhaust plumes were colorless and transparent under all tests conditions. There was some soot adhesion to the chamber wall, but no soot adhesion was observed on the main injector simulator orifices. Higher temperature igniter gas was required to ignite the main propellants of the preburner compared with that of the LO2/Gaseous Hydrogen (GH2) propellants combination.

Combustion in a High-Speed Compression-Ignition Engine

Science.gov (United States)

Rothrock, A M

1933-01-01

An investigation conducted to determine the factors which control the combustion in a high-speed compression-ignition engine is presented. Indicator cards were taken with the Farnboro indicator and analyzed according to the tangent method devised by Schweitzer. The analysis show that in a quiescent combustion chamber increasing the time lag of auto-ignition increases the maximum rate of combustion. Increasing the maximum rate of combustion increases the tendency for detonation to occur. The results show that by increasing the air temperature during injection the start of combustion can be forced to take place during injection and so prevent detonation from occurring. It is shown that the rate of fuel injection does not in itself control the rate of combustion.

Flow directing means for air-cooled transformers

Science.gov (United States)

Jallouk, Philip A.

1977-01-01

This invention relates to improvements in systems for force-cooling transformers of the kind in which an outer helical winding and an insulation barrier nested therein form an axially extending annular passage for cooling-fluid flow. In one form of the invention a tubular shroud is positioned about the helical winding to define an axially extending annular chamber for cooling-fluid flow. The chamber has a width in the range of from about 4 to 25 times that of the axially extending passage. Two baffles extend inward from the shroud to define with the helical winding two annular flow channels having hydraulic diameters smaller than that of the chamber. The inlet to the chamber is designed with a hydraulic diameter approximating that of the coolant-entrance end of the above-mentioned annular passage. As so modified, transformers of the kind described can be operated at significantly higher load levels without exceeding safe operating temperatures. In some instances the invention permits continuous operation at 200% of the nameplate rating.

Up-date on cyclone combustion and cyclone boilers

Energy Technology Data Exchange (ETDEWEB)

Carmo, Felipe Alfaia do; Nogueira, Manoel Fernandes Martins; Rocha, Rodrigo Carnera Castro da; Gazel, Hussein Felix; Martins, Diego Henrique dos Reis [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Campus Universitario Jose da Silveira Netto], E-mails: mfmn@ufpa.br, mfmn@ufpa.br

2010-07-01

The boiler concept has been around for more than 70 years, and there are many types available. Boilers provide steam or hot water for industrial and commercial use. The Federal University of Para (UFPA) through the research group EBMA (Energy,Biomass and Environment) has been developing cyclonic furnace with a water wall, a boiler, aiming to use regional timbers (sawdust) and agro-industries residues as fuel to produce steam to be used in industrial processes as well as in power generation,. The use of cyclonic combustion for burning waste instead of burning in a fixed bed is mainly due to two factors efficiency improvement causing a more compact boiler and less risk of explosion, since their process does not generate an accumulation of volatile. Present state-of-art for commercial cyclone boilers has as set up a cyclone combustor with two combustion chambers, in fluid communication, where there ducts for supplying air and fuel directly into the first chamber and for forming a cyclonic flow pattern and a heat exchanger surrounding the second chamber for keeping low combustion temperature in both chambers. This paper shows the results of a literature review about design, construction and operation of cyclonic boilers using solid, liquid or gaseous fuel. This information has been used for the design of a cyclone boiler to be constructed at UFPA for research purposes and its basic concept is presented at the end of this article. (author)

FAILURE MECHANISMS OF THERMAL BARRIER COATINGS INTERNAL COMBUSTION ENGINES AND llMPROVEMENTS

Directory of Open Access Journals (Sweden)

ADNAN PARLAK

2003-04-01

Full Text Available MechanicaJ properties of high performance ceramics have been improved to the point where their use in heat engines is possible. The high temperature strength and low thermal expansion properties of bigh performance ceramics offer an advantage over metals in the development of non-water cooling engine. However, because bard environment in diesel engine combustion chamber, solving the problem of durabiUty of TBC is important. DurabiUty of thermal barrier coatings(TBC is liınited by two main failure mechanisms: Therınal expansion nlİsmatch betwcen bond coat and top coat and bond coat oxidation. Both of these can cause failure of the ceramic top coat. Developments of recent years sholv that bond coats \\Vith higher oxidation resistance tend to have better coating system cyclic lives

LEP vacuum chamber, cross-section

CERN Multimedia

CERN PhotoLab

1983-01-01

Cross-section of the final prototype for the LEP vacuum chamber. The elliptic main-opening is for the beam. The small channel to the left is for the cooling water, to carry away the heat deposited by the synchrotron radiation. The square channel to the right houses the Non-Evaporable Getter (NEG) pump. The chamber is made from extruded aluminium. Its outside is clad with lead, to stop the synchrotron radiation emitted by the beam. For good adherence between Pb and Al, the Al chamber was coated with a thin layer of Ni. Ni being slightly magnetic, some resulting problems had to be overcome. See also 8301153.

Magma Chambers, Thermal Energy, and the Unsuccessful Search for a Magma Chamber Thermostat

Science.gov (United States)

Glazner, A. F.

2015-12-01

Although the traditional concept that plutons are the frozen corpses of huge, highly liquid magma chambers ("big red blobs") is losing favor, the related notion that magma bodies can spend long periods of time (~106years) in a mushy, highly crystalline state is widely accepted. However, analysis of the thermal balance of magmatic systems indicates that it is difficult to maintain a significant portion in a simmering, mushy state, whether or not the system is eutectic-like. Magma bodies cool primarily by loss of heat to the Earth's surface. The balance between cooling via energy loss to the surface and heating via magma accretion can be denoted as M = ρLa/q, where ρ is magma density, L is latent heat of crystallization, a is the vertical rate of magma accretion, and q is surface heat flux. If M>1, then magma accretion outpaces cooling and a magma chamber forms. For reasonable values of ρ, L, and q, the rate of accretion amust be > ~15 mm/yr to form a persistent volume above the solidus. This rate is extremely high, an order of magnitude faster than estimated pluton-filling rates, and would produce a body 10 km thick in 700 ka, an order of magnitude faster than geochronology indicates. Regardless of the rate of magma supply, the proportion of crystals in the system must vary dramatically with depth at any given time owing to transfer of heat. Mechanical stirring (e.g., by convection) could serve to homogenize crystal content in a magma body, but this is unachievable in crystal-rich, locked-up magma. Without convection the lower part of the magma body becomes much hotter than the top—a process familiar to anyone who has scorched a pot of oatmeal. Thermal models that succeed in producing persistent, large bodies of magma rely on scenarios that are unrealistic (e.g., omitting heat loss to the planet's surface), self-fulfilling prophecies (e.g., setting unnaturally high temperatures as fixed boundary conditions), or physically unreasonable (e.g., magma is intruded

LEP Vacuum Chamber

CERN Multimedia

1983-01-01

This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

Control device for combustible gas concentration

International Nuclear Information System (INIS)

Osawa, Yasuo.

1988-01-01

Purpose: To control the concentration of combustible gases such as hydrogen evolved in a reactor container upon loss-of-coolant accidents. Constitution: Combustible gases evolved from the lower area of a drywell in which a combustible atmosphere is liable to be formed locally are taken out through a take-out pipeway to the outside of a reactor container and processed by a hydrogen-oxygen recombiner. Combustible gases in other areas of the drywell are also introduced to the lower area of the drywell and then taken-out externally for procession. Further, combustible gases in the suppression chamber are introduced by the opening of a vacuum breaking valve through a gas supply pipe to the lower area of the drywell and fluids in the drywell are stirred and diluted with fluids exhausted from the gas supply pipe. Disposition of such take-out pipeway and gas supply pipe can reduce the possibility of forming local combustible atmosphere to improve the integrity of the reactor container. (Kamimura, M.)

Volatile Organic Compounds from Logwood Combustion: Emissions and Transformation under Dark and Photochemical Aging Conditions in a Smog Chamber.

Science.gov (United States)

Hartikainen, Anni; Yli-Pirilä, Pasi; Tiitta, Petri; Leskinen, Ari; Kortelainen, Miika; Orasche, Jürgen; Schnelle-Kreis, Jürgen; Lehtinen, Kari E J; Zimmermann, Ralf; Jokiniemi, Jorma; Sippula, Olli

2018-04-17

Residential wood combustion (RWC) emits high amounts of volatile organic compounds (VOCs) into ambient air, leading to formation of secondary organic aerosol (SOA), and various health and climate effects. In this study, the emission factors of VOCs from a logwood-fired modern masonry heater were measured using a Proton-Transfer-Reactor Time-of-Flight Mass Spectrometer. Next, the VOCs were aged in a 29 m 3 Teflon chamber equipped with UV black lights, where dark and photochemical atmospheric conditions were simulated. The main constituents of the VOC emissions were carbonyls and aromatic compounds, which accounted for 50%-52% and 30%-46% of the detected VOC emission, respectively. Emissions were highly susceptible to different combustion conditions, which caused a 2.4-fold variation in emission factors. The overall VOC concentrations declined considerably during both dark and photochemical aging, with simultaneous increase in particulate organic aerosol mass. Especially furanoic and phenolic compounds decreased, and they are suggested to be the major precursors of RWC-originated SOA in all aging conditions. On the other hand, dark aging produced relatively high amounts of nitrogen-containing organic compounds in both gas and particulate phase, while photochemical aging increased especially the concentrations of certain gaseous carbonyls, particularly acid anhydrides.

Combustion of Solid Fuel in a Vortex Furnace with Counter-swirling Flows

Directory of Open Access Journals (Sweden)

Redko A.A.

2017-12-01

Full Text Available The results of computer simulation of the processes of incineration of low-grade solid fuel-pulverized peat with a moisture content of 40%, an ash content of 6% are given. It has been determined the fields of distribution of temperature, velocity of gases and particles in the volume and at the outlet from the furnace. The three-dimensional temperature distribution in the combustion chamber indicates high-temperature combustion of peat particles at temperatures above 1700°C with liquid ash removal in the lower part of the furnace. It has been determined that when the furnace is cooled, it is not ensured combustion of the fuel completely. The value of the swirling flow rate at the outlet from the furnace (up to 370 m/s ensures the efficiency of separation of fuel particles, reducing heat losses from mechanical underburning. It is determined that the concentration of oxygen is close to zero over the entire height of the furnace, at an outlet from the furnace the oxygen concentration is 5...6%, since oxygen is supplied with excess (αв=1,2. The results of a numerical study showed that the diameter of peat particles affects the process of their combustion: coke particles with an initial diameter of 25 mkm to 250 mkm burn out by 96%. With an increase in particle diameter up to 1000 mkm, the degree of burn-out of coke decreases, but at the same time their removal decreases. It is shown that the furnace ensures the completeness of combustion of peat particles of peat 99.8%, volatiles is 100%.

Low pressure cooling seal system for a gas turbine engine

Science.gov (United States)

Marra, John J

2014-04-01

A low pressure cooling system for a turbine engine for directing cooling fluids at low pressure, such as at ambient pressure, through at least one cooling fluid supply channel and into a cooling fluid mixing chamber positioned immediately downstream from a row of turbine blades extending radially outward from a rotor assembly to prevent ingestion of hot gases into internal aspects of the rotor assembly. The low pressure cooling system may also include at least one bleed channel that may extend through the rotor assembly and exhaust cooling fluids into the cooling fluid mixing chamber to seal a gap between rotational turbine blades and a downstream, stationary turbine component. Use of ambient pressure cooling fluids by the low pressure cooling system results in tremendous efficiencies by eliminating the need for pressurized cooling fluids for sealing this gap.

Numerical investigation of high temperature synthesis gas premixed combustion via ANSYS Fluent

Directory of Open Access Journals (Sweden)

Pashchenko Dmitry

2018-01-01

Full Text Available A numerical model of the synthesis gas pre-mixed combustion is developed. The research was carried out via ANSYS Fluent software. Verification of the numerical results was carried out using experimental data. A visual comparison of the flame contours that obtained by the synthesis gas combustion for Re = 600; 800; 1000 was performed. A comparison of the wall temperature of the combustion chamber, obtained with the help of the developed model, with the results of a physical experiment was also presented. For all cases, good convergence of the results is observed. It is established that a change in the temperature of the syngas/air mixture at the inlet to the combustion chamber does not significantly affect the temperature of the combustion products due to the dissipation of the H2O and CO2 molecules. The obtained results are of practical importance for the design of heat engineering plants with thermochemical heat recovery.

Characterisation of laser ignition in hydrogen-air mixtures in a combustion bomb

Energy Technology Data Exchange (ETDEWEB)

Srivastava, Dhananjay Kumar; Agarwal, Avinash Kumar [Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur-208016 (India); Weinrotter, Martin; Wintner, Ernst [Photonics Institute, Vienna University of Technology, Gusshausstrasse 27, A-1040 Vienna (Austria); Iskra, Kurt [Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz (Austria)

2009-03-15

Laser-induced spark ignition of lean hydrogen-air mixtures was experimentally investigated using nanosecond pulses generated by Q-switched Nd:YAG laser (wavelength 1064 nm) at initial pressure of 3 MPa and temperature 323 K in a constant volume combustion chamber. Laser ignition has several advantages over conventional ignition systems especially in internal combustion engines, hence it is necessary to characterise the combustion phenomena from start of plasma formation to end of combustion. In the present experimental investigation, the formation of laser plasma by spontaneous emission technique and subsequently developing flame kernel was measured. Initially, the plasma propagates towards the incoming laser. This backward moving plasma (towards the focusing lens) grows much faster than the forward moving plasma (along the direction of laser). A piezoelectric pressure transducer was used to measure the pressure rise in the combustion chamber. Hydrogen-air mixtures were also ignited using a spark plug under identical experimental conditions and results are compared with the laser ignition ones. (author)

Visualization of flows in a motored rotary combustion engine using holographic interferometry

Science.gov (United States)

Hicks, Y. R.; Schock, H. J.; Craig, J. E.; Umstatter, H. L.; Lee, D. Y.

1986-01-01

The use of holographic interferometry to view the small- and large-scale flow field structures in the combustion chamber of a motored Wankel engine assembly is described. In order that the flow patterns of interest could be observed, small quantities of helium were injected with the intake air. Variation of the air flow patterns with engine speed, helium flow rate, and rotor position are described. The air flow at two locations within the combustion chamber was examined using this technique.

Universal crystal cooling device for precession cameras, rotation cameras and diffractometers

International Nuclear Information System (INIS)

Hajdu, J.; McLaughlin, P.J.; Helliwell, J.R.; Sheldon, J.; Thompson, A.W.

1985-01-01

A versatile crystal cooling device is described for macromolecular crystallographic applications in the 290 to 80 K temperature range. It utilizes a fluctuation-free cold-nitrogen-gas supply, an insulated Mylar crystal cooling chamber and a universal ball joint, which connects the cooling chamber to the goniometer head and the crystal. The ball joint is a novel feature over all previous designs. As a result, the device can be used on various rotation cameras, precession cameras and diffractometers. The lubrication of the interconnecting parts with graphite allows the cooling chamber to remain stationary while the crystal and goniometer rotate. The construction allows for 360 0 rotation of the crystal around the goniometer axis and permits any settings on the arcs and slides of the goniometer head (even if working at 80 K). There are no blind regions associated with the frame holding the chamber. Alternatively, the interconnecting ball joint can be tightened and fixed. This results in a set up similar to the construction described by Bartunik and Schubert where the cooling chamber rotates with the crystal. The flexibility of the systems allows for the use of the device on most cameras or diffractometers. THis device has been installed at the protein crystallographic stations of the Synchrotron Radiation Source at Daresbury Laboratory and in the Laboratory of Molecular Biophysics, Oxford. Several data sets have been collected with processing statistics typical of data collected without a cooling chamber. Tests using the full white beam of the synchrotron also look promising. (orig./BHO)

How to build a cloud chamber?

International Nuclear Information System (INIS)

Mariaud, C.

2012-01-01

The cloud chamber had its heyday in the first half of last century and allowed the discovery of new particles such as the anti-electron, the muon and the neutral and the charged kaon. The bubble chamber replaced it in the mid fifties. This article recalls the principle of the cloud chamber and shows, in a detailed way, how to proceed to build one with on-the-shelf materials. This design is based on the use of isopropanol whose liquefaction through the form of droplets materializes the track of the particle and on the use of combined Peltier cells (instead of CO 2 snow) to cool the chamber. This cloud chamber has been successfully used in schools to observe particles mainly electrons, alphas and muons generated by cosmic rays. (A.C.)

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

Energy Technology Data Exchange (ETDEWEB)

Duong Viet, D.

2002-07-01

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

Dust Combustion Safety Issues for Fusion Applications

Energy Technology Data Exchange (ETDEWEB)

L. C. Cadwallader

2003-05-01

This report summarizes the results of a safety research task to identify the safety issues and phenomenology of metallic dust fires and explosions that are postulated for fusion experiments. There are a variety of metal dusts that are created by plasma erosion and disruptions within the plasma chamber, as well as normal industrial dusts generated in the more conventional equipment in the balance of plant. For fusion, in-vessel dusts are generally mixtures of several elements; that is, the constituent elements in alloys and the variety of elements used for in-vessel materials. For example, in-vessel dust could be composed of beryllium from a first wall coating, tungsten from a divertor plate, copper from a plasma heating antenna or diagnostic, and perhaps some iron and chromium from the steel vessel wall or titanium and vanadium from the vessel wall. Each of these elements has its own unique combustion characteristics, and mixtures of elements must be evaluated for the mixture’s combustion properties. Issues of particle size, dust temperature, and presence of other combustible materials (i.e., deuterium and tritium) also affect combustion in air. Combustion in other gases has also been investigated to determine if there are safety concerns with “inert” atmospheres, such as nitrogen. Several coolants have also been reviewed to determine if coolant breach into the plasma chamber would enhance the combustion threat; for example, in-vessel steam from a water coolant breach will react with metal dust. The results of this review are presented here.

Engine 3E. NO{sub x} reduction by means of homogenisation of mixtures inside combustion chambers. Final report; Engine 3E. NO{sub x}-Reduktion durch Homogenisierung des Gemisches in Brennkammern. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Zarzalis, N.; Homann; Schubert

1999-11-05

This is the final report of the Technology Project 'NO{sub x} reduction by means of homogenisation of mixtures inside combustion chambers', which is part of the Engine 3E 2010 programme of the BMBF, which was to promote research in aircraft engineering. In this project, technologies were developed to achieve a 60% reduction of NO{sub x} emissions as compared to ICAO '95 in an annular combustion chamber in realistic operating conditions where the emissions of substances oher than NO{sub x} were to be of the same level as the emissions of modern jet drives. Further, the design of the new combustion chamber was to be conventional in order to retain the possibility of converting existing propulsion systems to the new technology. [German] Diese Notiz enthaelt den Abschlussbericht des Technologievorhabens 'NO{sub x}-Reduktion durch Homogenisierung des Gemisches in Brennkammern'. Das Vorhaben ist Teil des Luftfahrtfoerderprogramms Engine 3E 2010 der Bundesregierung und wird vom Bundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie (BMBF) unter dem Foerderkennzeichen 20T9540 gefoerdert. Das Programm wurde am 01. Juli 1995 begonnen und endete am 30. Juni 1999. Entsprechend dem Foerderantrag wurden in dem Vorhaben Einzeltechnologien erarbeitet, die erforderlich sind, um eine 60% Reduktion der NO{sub x}-Emissionen gegenueber ICAO '95 in einer Ringbrennkammer unter realistischen Betriebsbedingungen zu demonstrieren, wobei die restlichen Emissionen das Emissionsniveau moderner Triebwerke nicht ueberschreiten sollten. Darueber hinaus sollte das aeussere Design der zu entwickelnden Brennkammer sind von konventionellen Brennkammern nicht unterscheiden, um die Moeglichkeit der Umruestung von alten Triebwerken mit der Brennkammern der neuen Technologie offen zu halten. (orig.)

Experimental investigation of flash pyrolysis oil droplet combustion

DEFF Research Database (Denmark)

Ibrahim, Norazana; Jensen, Peter A.; Dam-Johansen, Kim

2013-01-01

at a temperature ranging between 1000 and 1400°C with an initial gas velocity of 1.6 m/s and oxygen concentration of 3%. The evolution of combustion of bio-oil droplets was recorded by a digital video camera. It was observed that the combustion behaviour of pyrolysis oil droplet differ from the heavy oil in terms......The aim of this work is to investigate and compare the combustion behaviour of a single droplet of pyrolysis oil derived from wheat straw and heavy fossil oil in a single droplet combustion chamber. The initial oil droplet diameters were in between 500 μm to 2500 μm. The experiments were performed...

LES and RANS modeling of pulverized coal combustion in swirl burner for air and oxy-combustion technologies

International Nuclear Information System (INIS)

Warzecha, Piotr; Boguslawski, Andrzej

2014-01-01

Combustion of pulverized coal in oxy-combustion technology is one of the effective ways to reduce the emission of greenhouse gases into the atmosphere. The process of transition from conventional combustion in air to the oxy-combustion technology, however, requires a thorough investigations of the phenomena occurring during the combustion process, that can be greatly supported by numerical modeling. The paper presents the results of numerical simulations of pulverized coal combustion process in swirl burner using RANS (Reynolds-averaged Navier–Stokes equations) and LES (large Eddy simulation) methods for turbulent flow. Numerical simulations have been performed for the oxyfuel test facility located at the Institute of Heat and Mass Transfer at RWTH Aachen University. Detailed analysis of the flow field inside the combustion chamber for cold flow and for the flow with combustion using different numerical methods for turbulent flows have been done. Comparison of the air and oxy-coal combustion process for pulverized coal shows significant differences in temperature, especially close to the burner exit. Additionally the influence of the combustion model on the results has been shown for oxy-combustion test case. - Highlights: • Oxy-coal combustion has been modeled for test facility operating at low oxygen ratio. • Coal combustion process has been modeled with simplified combustion models. • Comparison of oxy and air combustion process of pulverized coal has been done. • RANS (Reynolds-averaged Navier–Stokes equations) and LES (large Eddy simulation) results for pulverized coal combustion process have been compared

Cooled spool piston compressor

Science.gov (United States)

Morris, Brian G. (Inventor)

1993-01-01

A hydraulically powered gas compressor receives low pressure gas and outputs a high pressure gas. The housing of the compressor defines a cylinder with a center chamber having a cross-sectional area less than the cross-sectional area of a left end chamber and a right end chamber, and a spool-type piston assembly is movable within the cylinder and includes a left end closure, a right end closure, and a center body that are in sealing engagement with the respective cylinder walls as the piston reciprocates. First and second annual compression chambers are provided between the piston enclosures and center housing portion of the compressor, thereby minimizing the spacing between the core gas and a cooled surface of the compressor. Restricted flow passageways are provided in the piston closure members and a path is provided in the central body of the piston assembly, such that hydraulic fluid flows through the piston assembly to cool the piston assembly during its operation. The compressor of the present invention may be easily adapted for a particular application, and is capable of generating high gas pressures while maintaining both the compressed gas and the compressor components within acceptable temperature limits.

Propagation of a premixed flame in a divided-chamber combustor

Science.gov (United States)

Cattolica, R. J.; Barr, P. K.; Mansour, N. N.

1989-01-01

Experimental observations on the propagation of lean premixed ethylene-air flames in a divided-chamber combustion vessel have been compared with the results of numerical simulations based on a flame sheet-vortex dynamics model in axisymmetric coordinates. Flame speeds were found to increase from 10-24 cm/s as the equivalence ratio was varied from 0.5-0.65 in the experiments. Using the associated increase in gas velocity with equivalence ratio, the estimated Reynolds number in the experiment was changed from 1870 to 8090. Good agreement between experimental and theoretical results was obtained for the prechamber flame propagation rates and for the spatial and temporal development of the flame in the main combustion chamber at the lowest Reynolds number.

High temperature corrosion investigation in an oxyfuel combustion test rig

DEFF Research Database (Denmark)

Montgomery, Melanie; Bjurman, M.; Hjörnhede, A

2014-01-01

Oxyfuel firing and subsequent capture of CO2 is a way to reduce CO2 emissions from coal‐fired boilers. Literature is summarized highlighting results which may contribute to understanding of the corrosion processes in an oxyfuel boiler.Tests were conducted in a 500 kWth oxyfuel test facility...... constructed by Brandenburg Technical University to gain understanding into oxyfuel firing. Two air‐cooled corrosion probes were exposed in this oxyfuel combustion chamber where the fuel was lignite. Gas composition was measured at the location of testing. Various alloys from a 2½ Cr steel, austenitic steels...... to nickel alloys were exposed at set metal temperatures of 570 and 630 °C for 287 h. The specimens were investigated using light optical and scanning electron microscopy and X‐ray diffraction.The deposit on the probe contained predominantly CaSO4 and Fe2O3. Oxide thickness and depth of the precipitated...

Unsteady Motions in Combustion Chambers for Propulsion Systems

Science.gov (United States)

2006-12-01

active in wind musical instruments. In all such cases, °ow separation is involved, followed by instability of a shear layer and formation of vortices... musical instruments. The idea that vortices might be responsible for oscillations in a solid propellant rocket seems to have been proposed ¯rst by...Combustion Oscillation in a Ducted Premixed Flame," Inst. Mech. Engineers, Int. Conf. on Comb. in Eng., Oxford, pp. 85{94. Campos -Delgado, D.V., Scheuermans

System for cooling hybrid vehicle electronics, method for cooling hybrid vehicle electronics

Science.gov (United States)

France, David M.; Yu, Wenhua; Singh, Dileep; Zhao, Weihuan

2017-11-21

The invention provides a single radiator cooling system for use in hybrid electric vehicles, the system comprising a surface in thermal communication with electronics, and subcooled boiling fluid contacting the surface. The invention also provides a single radiator method for simultaneously cooling electronics and an internal combustion engine in a hybrid electric vehicle, the method comprising separating a coolant fluid into a first portion and a second portion; directing the first portion to the electronics and the second portion to the internal combustion engine for a time sufficient to maintain the temperature of the electronics at or below 175.degree. C.; combining the first and second portion to reestablish the coolant fluid; and treating the reestablished coolant fluid to the single radiator for a time sufficient to decrease the temperature of the reestablished coolant fluid to the temperature it had before separation.

A two-dimensional numerical study of the flow inside the combustion chamber of a motored rotary engine

Science.gov (United States)

Shih, T. I-P.; Yang, S. L.; Schock, H. J.

1986-01-01

A numerical study was performed to investigate the unsteady, multidimensional flow inside the combustion chambers of an idealized, two-dimensional, rotary engine under motored conditions. The numerical study was based on the time-dependent, two-dimensional, density-weighted, ensemble-averaged conservation equations of mass, species, momentum, and total energy valid for two-component ideal gas mixtures. The ensemble-averaged conservation equations were closed by a K-epsilon model of turbulence. This K-epsilon model of turbulence was modified to account for some of the effects of compressibility, streamline curvature, low-Reynolds number, and preferential stress dissipation. Numerical solutions to the conservation equations were obtained by the highly efficient implicit-factored method of Beam and Warming. The grid system needed to obtain solutions were generated by an algebraic grid generation technique based on transfinite interpolation. Results of the numerical study are presented in graphical form illustrating the flow patterns during intake, compression, gaseous fuel injection, expansion, and exhaust.

A two-dimensional numerical study of the flow inside the combustion chambers of a motored rotary engine

Science.gov (United States)

Shih, T. I. P.; Yang, S. L.; Schock, H. J.

1986-01-01

A numerical study was performed to investigate the unsteady, multidimensional flow inside the combustion chambers of an idealized, two-dimensional, rotary engine under motored conditions. The numerical study was based on the time-dependent, two-dimensional, density-weighted, ensemble-averaged conservation equations of mass, species, momentum, and total energy valid for two-component ideal gas mixtures. The ensemble-averaged conservation equations were closed by a K-epsilon model of turbulence. This K-epsilon model of turbulence was modified to account for some of the effects of compressibility, streamline curvature, low-Reynolds number, and preferential stress dissipation. Numerical solutions to the conservation equations were obtained by the highly efficient implicit-factored method of Beam and Warming. The grid system needed to obtain solutions were generated by an algebraic grid generation technique based on transfinite interpolation. Results of the numerical study are presented in graphical form illustrating the flow patterns during intake, compression, gaseous fuel injection, expansion, and exhaust.

Multi-stage combustion using nitrogen-enriched air

Science.gov (United States)

Fischer, Larry E.; Anderson, Brian L.

2004-09-14

Multi-stage combustion technology combined with nitrogen-enriched air technology for controlling the combustion temperature and products to extend the maintenance and lifetime cycles of materials in contact with combustion products and to reduce pollutants while maintaining relatively high combustion and thermal cycle efficiencies. The first stage of combustion operates fuel rich where most of the heat of combustion is released by burning it with nitrogen-enriched air. Part of the energy in the combustion gases is used to perform work or to provide heat. The cooled combustion gases are reheated by additional stages of combustion until the last stage is at or near stoichiometric conditions. Additional energy is extracted from each stage to result in relatively high thermal cycle efficiency. The air is enriched with nitrogen using air separation technologies such as diffusion, permeable membrane, absorption, and cryogenics. The combustion method is applicable to many types of combustion equipment, including: boilers, burners, turbines, internal combustion engines, and many types of fuel including hydrogen and carbon-based fuels including methane and coal.

Analysis of energy cascade utilization in a chemically recuperated scramjet with indirect combustion

International Nuclear Information System (INIS)

Qin, Jiang; Cheng, Kunlin; Zhang, Silong; Zhang, Duo; Bao, Wen; Han, Jiecai

2016-01-01

The working process of scramjet with regenerative cooling, which was actually the chemical recuperation process, was analyzed in view of energy cascade utilization. The indirect combustion was realized through pyrolysis reaction of fuel. The relative yields of thermal exergy obtained by indirect combustion have been predicted both assuming an ideal pyrolysis reaction and using the experimental results of thermal pyrolysis of n-decane. The results showed that the influence mechanism of regenerative cooling improved the scramjet engine performance by the energy cascade utilization, and the combustion process was supposed to be designed with the cooling process together to utilize the chemical energy of fuel in a more effective way. A maximum value of 11% of the relative yield was obtained with the ideal pyrolysis reaction while a value less than 3% existed in the thermal pyrolysis experiments because of the domination of chemical kinetics rather than chemical thermodynamics in the real experiments. In spite of the difference between the ideal and the present experimental results, the indirect combustion was prospective to achieve a better energy cascade utilization in a chemically recuperated scramjet if the pyrolysis reaction was further optimized. The results in this paper were beneficial for the performance optimization of a regenerative cooling scramjet. - Highlights: • A new method of energy cascade utilization in a chemically recuperated scramjet. • 11% exergy loss is reduced by ideal pyrolysis reaction with indirect combustion. • Regenerative cooling with chemical recuperation can improve engine performance.

INVESTIGATION OF THE FATE OF MERCURY IN A COAL COMBUSTION PLUME USING A STATIC PLUME DILUTION CHAMBER

Energy Technology Data Exchange (ETDEWEB)

Dennis L. Laudal

2001-11-01

The overall goal of the project was to further develop and then verify SPDC's ability to determine the physical and chemical transformations of mercury in combustion stack plumes. Specific objectives of the project were to perform controlled tests at the pilot scale using dynamic spiking of known mercury compounds (i.e., Hg{sup 0} and HgCl{sub 2}) to prove the ability of the SPDC to determine the following: whether mercury condenses onto particulate matter in a cooling plume; whether there is reduction of Hg{sup 2+} to Hg{sup 0} occurring in hygroscopic aerosols; whether condensed Hg{sup 2+} on particles is photochemically reduced to Hg{sup 0}; and whether or not the Solid Ontario Hydro mercury speciation method (SOH) provides the same results as the Ontario Hydro (OH) mercury speciation method.

Shock and vibration protection of submerged jet impingement cooling systems: Theory and experiment

International Nuclear Information System (INIS)

Haji Hosseinloo, Ashkan; Tan, Siow Pin; Yap, Fook Fah; Toh, Kok Chuan

2014-01-01

In the recent years, advances in high power density electronics and computing systems have pushed towards more advanced thermal management technologies and higher-capacity cooling systems. Among different types of cooling systems, jet impingement technology has gained attention and been widely used in different industries for its adaptability, cooling uniformity, large heat capacity, and ease of its localization. However, these cooling systems may not function properly in dynamically harsh environment inherent in many applications such as land, sea and air transportation. In this research article, a novel double-chamber jet impingement cooling system is fabricated and its performance is studied in harsh environment. Using the authors' previous studies, isolators with optimum properties are selected to ruggedize the chassis containing the cooling chamber against shock and random vibration. Experiments are conducted on both hard-mounted and isolated chassis and the cooling performance of the system is assessed using the inlet, and impingement surface temperatures of the cooling chamber. The experimental results show the isolation system prevents any failure that otherwise would occur, and also does not compromise the thermal performance of the system. - Highlights: • A novel double-chamber jet impingement cooling system was designed and fabricated. • Comprehensive set of random vibration and shock tests are conducted. • The isolation system proved to protect the cooling system properly against mechanical failure. • Cooling system performance was not significantly affected by the input random vibration and shock

CFD simulations for premixed hydrogen-air deflagration from a vented chamber

International Nuclear Information System (INIS)

Gera, B.; Ganju, S.

2015-01-01

In water cooled power reactors, significant quantities of hydrogen could be produced by a steam-zirconium (fuel clad) reaction following a postulated loss-of-coolant accident (LOCA) along with non-availability of Emergency Core Cooling System (ECCS). Hydrogen in air has the potential for uncontrolled combustion, which has given rise to public concern over the years. The generated hydrogen gets distributed in the different compartment of nuclear reactor containment and may form combustible mixture. Hence, various experimental activities have been performed around the world to investigate severe accident phenomena related to hydrogen combustion. Recently, with the rising concerns for local hydrogen control, numerical calculations for space resolved hydrogen distribution and combustion in the compartment have become an important requirement. Considering all these issues computations have been performed using commercial CFD code CFDACE+ for deflagration of lean dry hydrogen air mixture for a reported experiment. The paper describes the modelling details and main results of the investigation and comparison with experiments

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

KAUST Repository

Alfazazi, Adamu

2016-08-10

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

ANALYSIS OF INTERNAL COMBUSTION ENGINE WITH A NEW CONCEPT OF POROUS MEDIUM COMBUSTION FOR THE FUTURE CLEAN ENGINE

Directory of Open Access Journals (Sweden)

Ashok A Dhale

2010-01-01

Full Text Available At present, the emissions of internal combustion engine can only be improved by catalytic treatments of the exhaust gases. Such treatments, however, result in high costs and relatively low conversion efficiency. This suggests that a new combustion technique should be developed to yield improved primary combustion processes inside the engine with drastically reduced exhaust gas emissions. To fulfill all requirements, Dr. Franz Drust has proposed a new combustion concept to perform homogenous combustion in internal combustion engines. This concept used the porous medium combustion technique and is called "PM-engine". It is shown that the PM combustion technique can be applied to internal combustion engines. Theoretical considerations are presented for internal combustion engines, indicating that an overall improvement in thermal efficiency can be achieved for the PM-engine. This is explained and general performance of the new PM-engines is demonstrated for a single cylinder, water cooled, direct injection diesel engine. Verification of experiments at primary stage is described that were carried out as a part of the present study.

Effect of cooled EGR on performance and exhaust gas emissions in EFI spark ignition engine fueled by gasoline and wet methanol blends

Science.gov (United States)

Rohadi, Heru; Syaiful, Bae, Myung-Whan

2016-06-01

Fuel needs, especially the transport sector is still dominated by fossil fuels which are non-renewable. However, oil reserves are very limited. Furthermore, the hazardous components produced by internal combustion engine forces many researchers to consider with alternative fuel which is environmental friendly and renewable sources. Therefore, this study intends to investigate the impact of cooled EGR on the performance and exhaust gas emissions in the gasoline engine fueled by gasoline and wet methanol blends. The percentage of wet methanol blended with gasoline is in the range of 5 to 15% in a volume base. The experiment was performed at the variation of engine speeds from 2500 to 4000 rpm with 500 intervals. The re-circulated exhaust gasses into combustion chamber was 5%. The experiment was performed at the constant engine speed. The results show that the use of cooled EGR with wet methanol of 10% increases the brake torque up to 21.3%. The brake thermal efficiency increases approximately 39.6% using cooled EGR in the case of the engine fueled by 15% wet methanol. Brake specific fuel consumption for the engine using EGR fueled by 10% wet methanol decreases up to 23% at the engine speed of 2500 rpm. The reduction of CO, O2 and HC emissions was found, while CO2 increases.

Dew point measurements of flue gases in steam generators with brown coal combustion

Energy Technology Data Exchange (ETDEWEB)

Schinkel, W.

1980-01-01

This paper examines empirical data on sulfuric acid condensation and resulting internal corrosion in brown coal fired steam generators. Due to the high sulfur content in brown coal (0.5% to 5.0%) and relative short duration of the gases in the combustion chamber the concentrations of sulfur trioxide present in the flue gases can condense at the heat exchange surfaces of the steam generators. A number of diagrams show sulfuric acid dew point temperatures depending on brown coal sulfur content, the influence of combustion air supply on the dew point, and condensing speed and the rate of corrosion in relation to different heat exchange surface temperatures. The conclusion is made that a five-fold increase in corrosion can be caused by a 10 K higher flue gas dew point, a 5 K cooling of heating surfaces can also cause heavy corrosion at a certain dew point. Maximum corrosion results at 20 to 50 K differences between flue gas dew point and heat exchange surfaces. Optimum operation of steam generators with minimal internal corrosion requires the consideration of flue gas and heating surface temperatures as well as flue gas sulfur acid dew points. (10 refs.) (In German)

Cooling of wood briquettes

Directory of Open Access Journals (Sweden)

Adžić Miroljub M.

2013-01-01

Full Text Available This paper is concerned with the experimental research of surface temperature of wood briquettes during cooling phase along the cooling line. The cooling phase is an important part of the briquette production technology. It should be performed with care, otherwise the quality of briquettes could deteriorate and possible changes of combustion characteristics of briquettes could happen. The briquette surface temperature was measured with an IR camera and a surface temperature probe at 42 sections. It was found that the temperature of briquette surface dropped from 68 to 34°C after 7 minutes spent at the cooling line. The temperature at the center of briquette, during the 6 hour storage, decreased to 38°C.

Fluidised bed combustion system

International Nuclear Information System (INIS)

McKenzie, E.C.

1976-01-01

Fluidized bed combustion systems that facilitates the maintenance of the depth of the bed are described. A discharge pipe projects upwardly into the bed so that bed material can flow into its upper end and escape downwardly. The end of the pipe is surrounded by an enclosure and air is discharged into the enclosure so that material will enter the pipe from within the enclosure and have been cooled in the enclosure by the air discharged into it. The walls of the enclosure may themselves be cooled

Bottoming organic Rankine cycle configurations to increase Internal Combustion Engines power output from cooling water waste heat recovery

International Nuclear Information System (INIS)

Peris, Bernardo; Navarro-Esbrí, Joaquín; Molés, Francisco

2013-01-01

This work is focused on waste heat recovery of jacket cooling water from Internal Combustion Engines (ICEs). Cooling water heat does not always find use due to its low temperature, typically around 90 °C, and usually is rejected to the ambient despite its high thermal power. An efficient way to take benefit from the ICE cooling water waste heat can be to increase the power output through suitable bottoming Organic Rankine Cycles (ORCs). Thereby, this work simulates six configurations using ten non flammable working fluids and evaluates their performances in efficiency, safety, cost and environmental terms. Results show that the Double Regenerative ORC using SES36 gets the maximum net efficiency of 7.15%, incrementing the ICE electrical efficiency up to 5.3%, although requires duplicating the number of main components and high turbine size. A more rigorous analysis, based on the system feasibility, shows that small improvements in the basic cycle provide similar gains compared to the most complex schemes proposed. So, the single Regenerative ORC using R236fa and the Reheat Regenerative ORC using R134a seem suitable cycles which provide a net efficiency of 6.55%, incrementing the ICE electrical efficiency up to 4.9%. -- Highlights: • Suitable bottoming cycles for ICE cooling water waste heat recovery are studied. • Non flammable working fluids and various ORC configurations are evaluated. • Double regenerative cycle using SES36 is the most efficient configuration. • Regenerative and reheat regenerative ORCs seem feasible cycles. • Electrical efficiency of the ICE can be improved up to 5.3%

Experimental assessment of film cooling performance of short cylindrical holes on a flat surface

Science.gov (United States)

Singh, Kuldeep; Premachandran, B.; Ravi, M. R.

2016-12-01

The present study is an experimental investigation of film-cooling over a flat surface from the short cylindrical holes. The film cooling holes used in the combustion chamber and the afterburner liner of an aero engine has length-to-diameter (L/D) typically in the range 1-2, while the cooling holes used in turbine blades has L/D > 3. Based on the classification given in the literature, cooling holes with L/D ≤ 3 are named as short holes and cooling holes with L/D > 3 are named as long holes. Short film cooling holes cause jetting of the secondary fluid whereas the secondary fluid emerging from long holes has characteristics similar to fully developed turbulent flow in pipe. In order to understand the difference in the film cooling performance of long and short cooling holes, experimental study is carried out for five values of L/D in the range 1-5, five injection angles, α = 15°-90° and five mainstream Reynolds number 1.25 × 105-6.25 × 105 and two blowing ratios, M = 0.5-1.0. The surface temperature of the test plate is monitored using infrared thermography. The results obtained from the present study showed that the film-cooling effectiveness is higher for the longest holes (L/D = 5) investigated in the present work in comparison to that for the shorter holes. Short holes are found to give better effectiveness at the lowest investigated injection angle i.e. α = 15° in the near cooling hole region, whereas film cooling effectiveness obtained at injection angle, α = 45° is found to be better than other injection angles for longest investigated holes, i.e. L/D = 5.

Biogas utilization: Experimental investigation on biogas flameless combustion in lab-scale furnace

International Nuclear Information System (INIS)

Hosseini, Seyed Ehsan; Wahid, Mazlan Abdul

2013-01-01

Highlights: • High costs of biogas purification and low calorific value of biogas are the main obstacles of biogas utilization. • The energy of biogas can be extracted by flameless combustion without any modification in burner or combustion system. • The efficiency of biogas flameless combustion and conventional combustion were 53% and 32% respectively. • The temperature inside the biogas flameless chamber is uniform. • In biogas flameless combustion, NO x and CO 2 formation decrease drastically in comparison with traditional combustion. - Abstract: Biogas generated in the anaerobic digestion of biomass and organic wastes by micro-organisms can be applied for heating, transportation and power generation as a renewable energy source. However, low calorific value (LCV) of biogas is one the most important bottlenecks of biogas conversion into electrical or thermal energy. Indeed, the presence of corrosive gases such as H 2 S and water vapor in biogas components makes some dilemmas in biogas purification and utilization. In order to obtain the efficient biogas utilization method, different biogas resources, physical and chemical properties of biogas and biogas combustion characteristics should be considered. In this paper biogas was utilized in lab-scale flameless combustion furnace and the performance of flameless combustion chamber fueled by biogas has been presented. Results demonstrated that flameless combustion is one of the best feasible strategies for biogas utilization. Uniformity of temperature in the flameless furnace increases the durability of refractory and related equipment. Simplicity of the flameless burner, pollutant formation reduction and fuel consumption decreases are the main causes of biogas flameless combustion supremacy

Cooling facility of nuclear power plant

International Nuclear Information System (INIS)

Arai, Kenji; Nagasaki, Hideo.

1992-01-01

In a cooling device of a nuclear power plant, an exhaust pipe for an incondensible gas is branched. One of the branched exhaust pipes is opened in a pressure suppression pool water in a suppression chamber containing pool water and the other is opened at a lower portion of a dry well incorporating a pressure vessel. In a state where the pressure in the dry well is higher than that in the suppression chamber, an off-gas is exhausted effectively by way of the exhaustion pipe in communication with the suppression chamber. In a state where there is no difference between the pressures and the opening end of the exhaustion pipe in communication with the suppression chamber is sealed with water, off-gas is exhausted by way of the exhaustion pipe in communication with the lower portion of the dry well. Then, since the incondensible gas in a heat transfer pipe is not accumulated, after-heat can be removed efficiently. Satisfactory cooling is maintained even after the coincidence of the pressures in the dry well with that in the suppression chamber, to decrease a pressure in a reactor container. (N.H.)

Destruction of nuclear graphite using closed chamber incineration

International Nuclear Information System (INIS)

Senor, D.J.; Hollenberg, G.W.; Morgan, W.C.; Marianowski, L.G.

1994-01-01

Closed chamber incineration (CCI) is a novel technique by which irradiated nuclear graphite may be destroyed without the risk of radioactive cation release into the environment. The process utilizes an enclosed combustion chamber coupled with molten carbonate fuel cells (MCFCs). The transport of cations is intrinsically suppressed by the MCFCs, such that only the combustion gases are conducted through for release to the environment. An example CCI design was developed which had as its goal the destruction of graphite fuel elements from the Fort St. Vrain reactor (FSVR). By employing CCI, the volume of high level waste from the FSVR will be reduced by approximately 87 percent. Additionally, the incineration process will convert the SiC coating on the FSVR fuel particles to SiO 2 , thus creating a form potentially suitable for direct incorporation in a vitrification process stream. The design is compact, efficient, and makes use of currently available technology

Potentiality of low cost environmentally friendly chamber for storage of irradiated potato and onion

International Nuclear Information System (INIS)

Roy, S.K.; Chakrabarti, A.K.; Pal, R.K.

1994-01-01

Potatoes and onions are two important horticultural commodities in India. Refrigeration is an expensive system and it is beyond the means of the poor, small and marginal farmers. Based on the principle of direct evaporative cooling, the scientists of the Indian Agricultural Research Institute developed a zero energy cool chamber. The zero energy cool chamber was tried at different locations in the country and was found to be very effective in increasing the shelf life of the fruits and vegetables and decreasing the physiological loss in weight

Solid waste combustion for alpha waste incineration

International Nuclear Information System (INIS)

Orloff, D.I.

1981-02-01

Radioactive waste incinerator development at the Savannah River Laboratory has been augmented by fundamental combustion studies at the University of South Carolina. The objective was to measure and model pyrolysis and combustion rates of typical Savannah River Plant waste materials as a function of incinerator operating conditions. The analytical models developed in this work have been incorporated into a waste burning transient code. The code predicts maximum air requirement and heat energy release as a function of waste type, package size, combustion chamber size, and temperature. Historically, relationships have been determined by direct experiments that did not allow an engineering basis for predicting combustion rates in untested incinerators. The computed combustion rates and burning times agree with measured values in the Savannah River Laboratory pilot (1 lb/hr) and full-scale (12 lb/hr) alpha incinerators for a wide variety of typical waste materials

Device for flame combustion of liquid or solid samples in radioactive isotope trace indication

International Nuclear Information System (INIS)

Kaartinen, N.H.

1979-01-01

The plant or animal tissue containing T and/or 14 C isotope indicator is in a small ignition cage within the combustion chamber. The ignition cage consists of Nichrome which supports the ignition procedure. The combustion chamber is maintained at a temperature above the condensation temperature of the vapours escaping from the tissue (e.g. H 2 O). The thimble type ignition cage burns uniformly together with the sample. It is no longer necessary to make pellets of the sample. (DG) [de

Biomass downdraft gasifier with internal cyclonic combustion chamber: design, construction, and experimental results.

Science.gov (United States)

Patil, Krushna; Bhoi, Prakash; Huhnke, Raymond; Bellmer, Danielle

2011-05-01

An exploratory downdraft gasifier design with unique biomass pyrolysis and tar cracking mechanism is evolved at Oklahoma State University. This design has an internal separate combustion section where turbulent, swirling high-temperature combustion flows are generated. A series of research trials were conducted using wood shavings as the gasifier feedstock. Maximum tar cracking temperatures were above 1100°C. Average volumetric concentration levels of major combustible components in the product gas were 22% CO and 11% H(2). Hot and cold gas efficiencies were 72% and 66%, respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

Utilization of biogas released from palm oil mill effluent for power generation using self-preheated reactor

International Nuclear Information System (INIS)

Hosseini, Seyed Ehsan; Wahid, Mazlan Abdul

2015-01-01

Highlights: • A lab-scale reactor called self-preheating flameless combustion (SPFC) system is experimented. • Feasibility of power generation by POME biogas is modeled using SPFC system. • 4 MW power is available by POME biogas utilization in a typical palm oil mill with 300,000 tons production. • The rate of power generation increases when 2% hydrogen is added to POME biogas ingredients. - Abstract: In palm oil mills, for one ton crude palm oil (CPO) production, 70 m"3 biogas is released from palm oil mill effluent (POME) which can endanger the environment. Palm oil mills without appropriate strategies for biogas collection can participate in greenhouse gases (GHGs) generation actively. In this paper, a typical palm oil mill with annual capacity of 300,000 ton oil palm production and 3 MW electricity demand is considered as a pilot plant and feasibility of power generation by POME biogas is modeled by Aspen Plus considering flameless mode in combustion system. A new design of lab-scale flameless reactor called self-preheated flameless combustion (SPFC) system is presented and employed in power generation modeling. In SPFC system, the flameless chamber is employed as a heater to preheat an oxidizer over the self-ignition temperature of the fuel. A helical stainless steel pipe (called self-preheating pipe) is installed inside the chamber to conduct the oxidizer from exhaust zone to the combustion zone inside the chamber and preheat oxidizer. In the flameless mode, the diluted oxidizer is injected to the helical pipe from the exhaust zone and the preheated oxidizer at the burner is conducted to the flameless furnace through a distributor. In SPFC system external heater for preheating oxidizer is removed and the rate of power generation increases. The results show that 10.8 MW power could be generated in ultra-lean POME biogas SPFC. However, the rate of pollutant especially CO_2 and NO_x is high in this circumstances. In stoichiometric condition, 4 MW power

Fire-detection device with an ionization chamber

Energy Technology Data Exchange (ETDEWEB)

Conforti, F J; Ogden, W L

1974-10-14

The invention fire-detector in which a detecting circuit of adjustable sensitivity is connected to an ionization chamber sensitive to combustion products. An appropriate circuit is adapted to check the operation and to determine if: the apparatus is duly fed with power; the detector is working; and the apparatus is working at the appropriate sensitivity.

Hydrocarbon-Fuel/Combustion-Chamber-Liner Materials Compatibility

Science.gov (United States)

1991-04-01

Grains, Leaving a Rough, Highly Pitted Surface 13 V (a) (b) ALA " I~ 4~ (0) (d) Figure 7. Cooling Channel Surface Features Resulting From the Overall...Canada or Terrell County, Texas as compared to natural gas from Rio Arriba County, New Mexico. Thus, the viability of using field gas feedstock...possible source of higher volumes in the more distant future. TABLE.14 COMPOSITION OF VARIOUS NATURAL GAS FIELDS Rio Olds Cliffside Arriba Terrel

Method and Apparatus for Thermal Spraying of Metal Coatings Using Pulsejet Resonant Pulsed Combustion

Science.gov (United States)

Paxson, Daniel E. (Inventor)

2014-01-01

An apparatus and method for thermal spraying a metal coating on a substrate is accomplished with a modified pulsejet and optionally an ejector to assist in preventing oxidation. Metal such as Aluminum or Magnesium may be used. A pulsejet is first initiated by applying fuel, air, and a spark. Metal is inserted continuously in a high volume of metal into a combustion chamber of the pulsejet. The combustion is thereafter controlled resonantly at high frequency and the metal is heated to a molten state. The metal is then transported from the combustion chamber into a tailpipe of said pulsejet and is expelled therefrom at high velocity and deposited on a target substrate.

Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion

KAUST Repository

Jing, Wei; Wu, Zengyang; Roberts, William L.; Fang, Tiegang

2016-01-01

Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement

Aqueous self-cooled blanket concepts for fusion reactors

International Nuclear Information System (INIS)

Varsamis, G.; Embrechts, M.J.; Steiner, D.; Deutsch, L.; Gierszewski, P.

1987-01-01

A novel aqueous self-cooled blanket (ASCB) concept has been proposed. The water coolant also serves as the tritium breeding medium by dissolving small amounts of lithium compound in the water. The tritium recovery requirements of the ASCB concept may be facilitated by the novel in-situ radiolytic tritium separation technique in development at Chalk River Nuclear Laboratories. In this separation process deuterium gas is bubbled through the blanket coolant. Due to radiation induced processes, the equilibrium constant favors tritium migration to the deuterium gas stream. It is expected that the inherent simplicity of this design will result in a highly reliable, safe and economically attractive breeding blanket for fusion reactors. The available base of relevant information accumulated through water-cooled fission reactor programs should greatly facilitate the R and D effort required to validate the proposed blanket concept. Tests for tritium separation and corrosion compatibility show encouraging results for the feasibility of this concept

Combustion modelling of a fuel oil flame; Modelisation de la combustion d`une flamme de fuel

Energy Technology Data Exchange (ETDEWEB)

Flour, I.; Mechitouan, N.

1996-10-01

The combustion modelling of a fuel oil flame has been realised in the scope of the R and D `Combustion Turbines`. This report presents the results of the 2D simulation of a fuel oil flame (n-octane), at atmospherical pressure, without swirl, realised using the Eulerian two-phase flow software Melodif. This calculation has been defined in collaboration with IFP, using experimental data from the IFRP. The hollow cone spray of liquid fuel is injected in the middle of the combustion chamber, with a co-flowing annular air. The furnace diameter is 2 meter and its length is 6,25 meter. A large recirculation zone is induced by the air flow, and leads to take into account the whole furnace, in order to avoid some problems with the limit conditions at the outlet. This calculation deals with droplets evaporation, gaseous phase combustion and radiation heat transfer. Predictions concerning gaseous axial mean velocity and mean temperature gradient in the flame, are in good agreement with measurements. However the temperature is too low in the peripheral zone of the flow. This is probably due to the fact that heat exchanges at the wall furnace are not correctly represented, because of a lack of detailed limit conditions for the walls. The mean radial velocity is not so well predicted, but this measurement is also quite difficult in a strongly longitudinal flow. The results concerning the dispersed phase will not be compared, because no measurements on the liquid fuel were available. As it has been experimentally observed, the simulation shows that the fuel oil spray quickly evaporates as it enters the combustion chamber. This result allows to propose to use an homogeneous approach (hypothesis of no-slipping between the two phases) in an Eulerian one-phase flow code, in case of a 3D simulation of liquid fuel turbine. (authors)

Experimental investigation of wood combustion in a fixed bed with hot air

NARCIS (Netherlands)

Markovic, Miladin; Bramer, Eduard A.; Brem, Gerrit

2014-01-01

Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically,

Hydrogen-oxygen powered internal combustion engine

Science.gov (United States)

Cameron, H.; Morgan, N.

1970-01-01

Hydrogen at 300 psi and oxygen at 800 psi are injected sequentially into the combustion chamber to form hydrogen-rich mixture. This mode of injection eliminates difficulties of preignition, detonation, etc., encountered with carburated, spark-ignited, hydrogen-air mixtures. Ignition at startup is by means of a palladium catalyst.

Printed indium gallium zinc oxide transistors. Self-assembled nanodielectric effects on low-temperature combustion growth and carrier mobility.

Science.gov (United States)

Everaerts, Ken; Zeng, Li; Hennek, Jonathan W; Camacho, Diana I; Jariwala, Deep; Bedzyk, Michael J; Hersam, Mark C; Marks, Tobin J

2013-11-27

Solution-processed amorphous oxide semiconductors (AOSs) are emerging as important electronic materials for displays and transparent electronics. We report here on the fabrication, microstructure, and performance characteristics of inkjet-printed, low-temperature combustion-processed, amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) grown on solution-processed hafnia self-assembled nanodielectrics (Hf-SANDs). TFT performance for devices processed below 300 °C includes >4× enhancement in electron mobility (μFE) on Hf-SAND versus SiO2 or ALD-HfO2 gate dielectrics, while other metrics such as subthreshold swing (SS), current on:off ratio (ION:IOFF), threshold voltage (Vth), and gate leakage current (Ig) are unchanged or enhanced. Thus, low voltage IGZO/SAND TFT operation (IGZO combustion processing leaves the underlying Hf-SAND microstructure and capacitance intact. This work establishes the compatibility and advantages of all-solution, low-temperature fabrication of inkjet-printed, combustion-derived high-mobility IGZO TFTs integrated with self-assembled hybrid organic-inorganic nanodielectrics.

Quantification and characterization of emissions from small-scale biofuel combustion; Kvantifiering och karakterisering av faktiska utslaepp fraan smaaskalig biobraensleeldning

Energy Technology Data Exchange (ETDEWEB)

Johansson, Linda; Gustavsson, Lennart; Johansson, Mathias; Oesterberg, Stefan; Tullin, Claes; Persson, Henrik [Swedish National Testing and Research Inst., Boraas (Sweden); Cooper, David; Sjoedin, Aake; Potter, Annika; Brorstroem-Lunden, Eva [Swedish Environmental Research Institute, Goeteborg (Sweden)

2003-09-01

This report is the final report of a project within the BHM research program. A comprehensive set of emission measurements has been conducted on domestic biomass boilers for wood logs and wood pellets. Within the project development of a simple method for field sampling has also been included. During the emission studies, different boilers with respect to age, design, and biomass fuels are included in the study, which also covers two oil-fired boilers for comparison. The total number of measurements cases was 29, from which 25 were measured at the laboratory and the remaining in field. Two of the cases were domestic oil burning, and were included as a comparison. The gas measurements comprised carbon monoxide (CO), carbon dioxide (CO{sub 2} ), oxygen (O{sub 2} ), total organic carbons (TOC), nitrogen oxides (NO{sub x} ), polycyclic aromatic hydrocarbons (PAH), and 33 volatile organic compounds (VOC). Particle emissions were characterised by mass concentration, number concentration, and the corresponding particle size distributions. The mass concentration of particles ranged from 13 mg/MJ (wood pellets) up to 2200 mg/MJ for a water cooled wood boiler without heat storage tank. The CO emission increased with increased air ratio, which indicates that air supply was not the limiting parameter for CO burnout. Poor combustion conditions could instead be explained by poor mixing conditions, or that the excess air was that large that it can be suspected to cool the combustion chamber, resulting in high CO emissions. The TOC emission was shown to correlate to the CO emission. TOC varied between 1 and 4800 mg/MJ, presented as methane-equivalents, and CO-emissions between 30 and 16400 mg/MJ. Both TOC and CO are indicators of combustion conditions. The large variations in concentrations can be explained by the large differences in combustion devices, operation of the equipment, and fuel-quality, investigated. Methane made up the largest fraction of the VOC emissions in all of

Performance of a Compression-ignition Engine with a Precombustion Chamber Having High-Velocity Air Flow

Science.gov (United States)

Spanogle, J A; Moore, C S

1931-01-01

Presented here are the results of performance tests made with a single-cylinder, four stroke cycle, compression-ignition engine. These tests were made on a precombustion chamber type of cylinder head designed to have air velocity and tangential air flow in both the chamber and cylinder. The performance was investigated for variable load and engine speed, type of fuel spray, valve opening pressure, injection period and, for the spherical chamber, position of the injection spray relative to the air flow. The pressure variations between the pear-shaped precombustion chamber and the cylinder for motoring and full load conditions were determined with a Farnboro electric indicator. The combustion chamber designs tested gave good mixing of a single compact fuel spray with the air, but did not control the ensuing combustion sufficiently. Relative to each other, the velocity of air flow was too high, the spray dispersion by injection too great, and the metering effect of the cylinder head passage insufficient. The correct relation of these factors is of the utmost importance for engine performance.

Experimental apparatus with full optical access for combustion experiments with laminar flames from a single circular nozzle at elevated pressures.

Science.gov (United States)

Joo, Peter H; Gao, Jinlong; Li, Zhongshan; Aldén, Marcus

2015-03-01

The design and features of a high pressure chamber and burner that is suitable for combustion experiments at elevated pressures are presented. The high pressure combustion apparatus utilizes a high pressure burner that is comprised of a chamber burner module and an easily accessible interchangeable burner module to add to its flexibility. The burner is well suited to study both premixed and non-premixed flames. The optical access to the chamber is provided through four viewports for direct visual observations and optical-based diagnostic techniques. Auxiliary features include numerous access ports and electrical connections and as a result, the combustion apparatus is also suitable to work with plasmas and liquid fuels. Images of methane flames at elevated pressures up to 25 atm and preliminary results of optical-based measurements demonstrate the suitability of the high pressure experimental apparatus for combustion experiments.

HYLIFE-II reactor chamber design refinements

International Nuclear Information System (INIS)

House, P.A.

1994-06-01

Mechanical design features of the reactor chamber for the HYLIFE-II inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams (Li 2 BeF 4 ) are used for shielding and blast protection of the chamber walls. The system is designed for a 6 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (>12 m/s) salt streams and also recover up to half of the dynamic head. Cost estimates for a 1 GWe and 2 GWe reactor chamber are presented

PEP cooling water systems and underground piped utilities design criteria report

International Nuclear Information System (INIS)

Hall, F.; Robbins, D.

1975-10-01

This paper discusses the cooling systems required by the PEP Storage Ring. Particular topics discussed are: Cooling tower systems, RF cavity and vacuum chamber LCW cooling systems, klystron and ring magnet LLW cooling systems, Injection magnet LCW Cooling Systems; PEP interaction area detector LCW Cooling Systems; and underground piped utilities. 1 ref., 20 figs

Multidisciplinary approach to materials selection for bipropellant ...

Indian Academy of Sciences (India)

The second method to cool combustion chamber is the unsteady state ... propellant. Engines that have this kind of cooling are, for .... tion velocity and CAbl is ablation heat coefficient. ... propellant flow, TPS and control volume lead to Eq. (9).

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

Film Cooled Recession of SiC/SiC Ceramic Matrix Composites: Test Development, CFD Modeling and Experimental Observations

Science.gov (United States)

Zhu, Dongming; Sakowski, Barbara A.; Fisher, Caleb

2014-01-01

SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. However, the environmental stability of Si-based ceramics in high pressure, high velocity turbine engine combustion environment is of major concern. The water vapor containing combustion gas leads to accelerated oxidation and corrosion of the SiC based ceramics due to the water vapor reactions with silica (SiO2) scales forming non-protective volatile hydroxide species, resulting in recession of the ceramic components. Although environmental barrier coatings are being developed to help protect the CMC components, there is a need to better understand the fundamental recession behavior of in more realistic cooled engine component environments.In this paper, we describe a comprehensive film cooled high pressure burner rig based testing approach, by using standardized film cooled SiCSiC disc test specimen configurations. The SiCSiC specimens were designed for implementing the burner rig testing in turbine engine relevant combustion environments, obtaining generic film cooled recession rate data under the combustion water vapor conditions, and helping developing the Computational Fluid Dynamics (CFD) film cooled models and performing model validation. Factors affecting the film cooled recession such as temperature, water vapor concentration, combustion gas velocity, and pressure are particularly investigated and modeled, and compared with impingement cooling only recession data in similar combustion flow environments. The experimental and modeling work will help predict the SiCSiC CMC recession behavior, and developing durable CMC systems in complex turbine engine operating conditions.

EXPERIMENTAL INSTALLATION FOR AN ASSESSMENT OF METHODS OF WATER SUPPLY IN AN INTERNAL COMBUSTION ENGINE

Directory of Open Access Journals (Sweden)

A. V. Bizhaev

2015-01-01

Full Text Available The water additive to fuel became one of effective ways of the solution of the main problems of the piston internal combustion engines (ICE as it reduces thermal factor of the engine, toxic emissions of exhaust products, and also increases efficiency by some operating modes. The way of fuel and air mix with water feeding in the combustion chamber has a great influence on process of combustion. Experimental installation for obtaining comparative characteristics of the main methods of water supply in the ICE combustion chamber was created. It was defined that there are two ways of water supply in the combustion chamber. At the first way water feed is carried out in the form of a water fuel emulsion which moves to the combustion chamber through a nozzle by means of the fuel pump with a high pressure. At the second way water arrives with air through the spraying element - the carburetor or a nozzle. This way is very simple in difference of emulsion feeding. The easiest way is nozzles application. It was established that the emulsion as the non-uniform highly dispersed fluid can be divide into components. Therefore it is necessary to use during the feeding system operation special emulsifiers with air for the uniformity water getting to the cylinder. The system for each nozzle opening at some point was offered. System of feedback with sensors of exhaust gases temperature in a final collector for adjustment of duration of injection was worked out. It was showed that at the developed experimental stand it is possible to carry out tests at various power modes. As result it will be possible to estimate both ways of fuel and air mix with water feeding.

Numerical analysis on the combustion and emission characteristics of forced swirl combustion system for DI diesel engines

International Nuclear Information System (INIS)

Su, LiWang; Li, XiangRong; Zhang, Zheng; Liu, FuShui

2014-01-01

Highlights: • A new combustion system named FSCS for DI diesel engines was proposed. • Fuel/air mixture formation was improved for the application of FSCS. • The FSCS showed a good performance on emission characteristics. - Abstract: To optimize the fuel/air mixture formation and improve the environmental effect of direct injection (DI) diesel engines, a new forced swirl combustion system (FSCS) was proposed concerned on unique design of the geometric shape of the combustion chamber. Numerical simulation was conducted to verify the combustion and emission characteristics of the engines with FSCS. The fuel/air diffusion, in-cylinder velocity distribution, turbulent kinetic energy and in-cylinder temperature distribution were analyzed and the results shown that the FSCS can increase the area of fuel/air diffusion and improve the combustion. The diesel engine with FSCS also shown excellent performance on emission. At full load condition, the soot emission was significantly reduced for the improved fuel/air mixture formation. There are slightly difference for the soot and NO emission between the FSCS and the traditional omega combustion system at lower load for the short penetration of the fuel spray

CFD modelling wall heat transfer inside a combustion chamber using ANSYS forte

Science.gov (United States)

Plengsa-ard, C.; Kaewbumrung, M.

2018-01-01

A computational model has been performed to analyze a wall heat transfer in a single cylinder, direct injection and four-stroke diesel engine. A direct integration using detailed chemistry CHEMKIN is employed in a combustion model and the Reynolds Averaged Navier Stokes (RANS) turbulence model is used to simulate the flow in the cylinder. To obtain heat flux results, a modified classical variable-density wall heat transfer model is also performed. The model is validated using experimental data from a CUMMINs engine operated with a conventional diesel combustion. One operating engine condition is simulated. Comparisons of simulated in-cylinder pressure and heat release rates with experimental data shows that the model predicts the cylinder pressure and heat release rates reasonably well. The contour plot of instantaneous temperature are presented. Also, the contours of predicted heat flux results are shown. The magnitude of peak heat fluxes as predicted by the wall heat transfer model is in the range of the typical measure values in diesel combustion.

Whole-body pre-cooling and heat storage during self-paced cycling performance in warm humid conditions.

Science.gov (United States)

Kay, D; Taaffe, D R; Marino, F E

1999-12-01

The aim of this study was to establish the effect that pre-cooling the skin without a concomitant reduction in core temperature has on subsequent self-paced cycling performance under warm humid (31 degrees C and 60% relative humidity) conditions. Seven moderately trained males performed a 30 min self-paced cycling trial on two separate occasions. The conditions were counterbalanced as control or whole-body pre-cooling by water immersion so that resting skin temperature was reduced by approximately 5-6 degrees C. After pre-cooling, mean skin temperature was lower throughout exercise and rectal temperature was lower (P body sweat fell from 1.7+/-0.1 l x h(-1) to 1.2+/-0.1 l h(-1) (P < 0.05). The distance cycled increased from 14.9+/-0.8 to 15.8+/-0.7 km (P < 0.05) after pre-cooling. The results indicate that skin pre-cooling in the absence of a reduced rectal temperature is effective in reducing thermal strain and increasing the distance cycled in 30 min under warm humid conditions.

Biomass utilization for green environment: Co-combustion of diesel fuel and producer gas in thermal application

International Nuclear Information System (INIS)

Hussain, A.; Ani, F.N.; Mehamed, A.F.

2007-01-01

Study of co-combustion of diesel oil and producer gas from a gasifier, individually as well as combined, in an experimental combustion chamber revealed that the producer gas can be co-combusted with liquid fuel. The process produced more CO, NO/sub x/, SO/sub 2/ and CO/sub 2/ as compared to the combustion of diesel oil alone; the exhaust temperature for the process was higher than the diesel combustion alone. (author)

Roof slab cooling device in a FBR type reactor

International Nuclear Information System (INIS)

Tarutani, Kohei

1987-01-01

Purpose: To obtain a roof slab cooling device capable of retaining cooling performance even in a case of electric power supply stop or failure and effective from economical point of view. Constitution: Atmospheric air is introduced into the cooling chamber of a proof slab and spontaneously passed to a exit pipeway connected to a stack thereby cooling the roof slab. Specifically, atmospheric air entered from the inlet pipeway is introduced to the cooling chamber and absorbs heat generate from the inside of the reactor container. Warmed air is sucked from the exit pipeway and then released into the atmosphere passing through the stack. The air cools the roof slab during circulation due to spontaneous passage and keeps the slab at a low temperature. Since the air is passed spontaneously, no power such as for a blower is required at all and, if the electric power supply should be lost, the cooling power can be maintained as it is to provide a high reliability. Further, since no electric power is required for the blowing power, it has high economical merit. (Horiuchi, T.)

Low temperature spray combustion of acetone–butanol–ethanol (ABE) and diesel blends

International Nuclear Information System (INIS)

Zhou, Nan; Huo, Ming; Wu, Han; Nithyanandan, Karthik; Lee, Chia-fon F.; Wang, Qingnian

2014-01-01

Highlights: • Combustion characteristics of acetone–butanol–ethanol (ABE) and diesel blends. • Feasibility of ABE to be blended directly with diesel in engine. • Conventional and low temperature combustion in constant volume chamber. • ABE–diesel blends can suppress the soot formation and achieve better combustion. - Abstract: The combustion characteristics of acetone–butanol–ethanol (ABE) and diesel blends were studied in a constant volume chamber under both conventional diesel combustion and low temperature combustion (LTC) conditions. In this work, 20 vol.% ABE without water (ABE20) was mixed with diesel and the vol.% of acetone, butanol and ethanol were kept at 30%, 60% and 10% respectively. The advantageous combustion characteristics of ABE-diesel include higher oxygen content which promotes soot oxidation compared to pure diesel; longer ignition delay and soot lift-off length allowing more air entrainment upstream of the spray jet thus providing better air–fuel mixing. Based on the analysis, it is found that at low ambient temperature of 800 K and ambient oxygen of 11%, ABE20 presented close-to-zero soot luminosity with better combustion efficiency compared to D100 suggesting that ABE, an intermediate product during ABE fermentation, is a very promising alternative fuel to be directly used in diesel engines especially under LTC conditions. Meanwhile, ABE–diesel blends contain multiple components possessing drastically different volatilities, which greatly favor the occurrence of micro-explosion. This feature may result in better atomization and air–fuel mixing enhancement, which all contribute to the better combustion performance of ABE20 at LTC conditions

Flame behavior and thermal structure of combusting plane jets with and without self-excited transverse oscillations

Science.gov (United States)

Huang, Rong Fung; Kivindu, Reuben Mwanza; Hsu, Ching Min

2018-06-01

The flame behavior and thermal structure of combusting plane jets with and without self-excited transverse oscillations were investigated experimentally. The transversely-oscillating plane jet was generated by a specially designed fluidic oscillator. Isothermal flow patterns were observed using the laser-assisted smoke flow visualization method. Meanwhile, the flame behaviour was studied using instantaneous and long-exposure photography techniques. Temperature distributions and combustion-product concentrations were measured using a fine-wire type R thermocouple and a gas analyzer, respectively. The results showed that the combusting transversely-oscillating plane jets had distributed turbulent blue flames with plaited-like edges, while the corresponding combusting non-oscillating plane jet had laminar blue-edged flames in the near field. At a high Reynolds number, the transversely-oscillating jet flames were significantly shorter and wider with shorter reaction-dominated zones than those of the non-oscillating plane jet flames. In addition, the transversely-oscillating combusting jets presented larger carbon dioxide and smaller unburned hydrocarbon concentrations, as well as portrayed characteristics of partially premixed flames. The non-oscillating combusting jets presented characteristics of diffusion flames, and the transversely-oscillating jet flame had a combustion performance superior to its non-oscillating plane jet flame counterpart. The high combustion performance of the transversely-oscillating jets was due to the enhanced entrainment, mixing, and lateral spreading of the jet flow, which were induced by the vortical flow structure generated by lateral periodic jet oscillations, as well as the high turbulence created by the breakup of the vortices.

Flame behavior and thermal structure of combusting plane jets with and without self-excited transverse oscillations

Science.gov (United States)

Huang, Rong Fung; Kivindu, Reuben Mwanza; Hsu, Ching Min

2017-12-01

The flame behavior and thermal structure of combusting plane jets with and without self-excited transverse oscillations were investigated experimentally. The transversely-oscillating plane jet was generated by a specially designed fluidic oscillator. Isothermal flow patterns were observed using the laser-assisted smoke flow visualization method. Meanwhile, the flame behaviour was studied using instantaneous and long-exposure photography techniques. Temperature distributions and combustion-product concentrations were measured using a fine-wire type R thermocouple and a gas analyzer, respectively. The results showed that the combusting transversely-oscillating plane jets had distributed turbulent blue flames with plaited-like edges, while the corresponding combusting non-oscillating plane jet had laminar blue-edged flames in the near field. At a high Reynolds number, the transversely-oscillating jet flames were significantly shorter and wider with shorter reaction-dominated zones than those of the non-oscillating plane jet flames. In addition, the transversely-oscillating combusting jets presented larger carbon dioxide and smaller unburned hydrocarbon concentrations, as well as portrayed characteristics of partially premixed flames. The non-oscillating combusting jets presented characteristics of diffusion flames, and the transversely-oscillating jet flame had a combustion performance superior to its non-oscillating plane jet flame counterpart. The high combustion performance of the transversely-oscillating jets was due to the enhanced entrainment, mixing, and lateral spreading of the jet flow, which were induced by the vortical flow structure generated by lateral periodic jet oscillations, as well as the high turbulence created by the breakup of the vortices.

Laboratory study on the cooling effect of flash water evaporative cooling technology for ventilation and air-conditioning of buildings

DEFF Research Database (Denmark)

Fang, Lei; Yuan, Shu; Yang, Jianrong

2016-01-01

in warm/hot and dry environment where dehumidification of outdoor air is not needed. A laboratory experiment was designed and conducted to evaluate the cooling effectiveness of this technology. The experiment was conducted in a twin-climate chamber. One chamber simulated warm/hot and dry outdoor...... evaporation. Two outdoor summer climates were simulated in the study, i.e. the design summer climate of Las Vegas and the extreme summer climate of Copenhagen represented hot/dry and warm/dry climates. The results showed that the flash evaporative cooling technology, a simple and green cooling technology......, is effective for ventilation and air-conditioning in warm/hot and dry climate zones. The technology can provide fresh outdoor air with a temperature of 4 to 7 °C lower than room air temperature....

Pyrolysis oil combustion in a horizontal box furnace with an externally mixed nozzle

Science.gov (United States)

Combustion characteristics of neat biomass fast-pyrolysis oil were studied in a horizontal combustion chamber with a rectangular cross-section. An air-assisted externally mixed nozzle known to successfully atomize heavy fuel oils was installed in a modified nominal 100 kW (350,000 BTU/h nominal cap...

Improved thermal/MHD design of self-cooled blankets for high-power-density fusion reactors

International Nuclear Information System (INIS)

Sedehi, S.; Lund, K.O.

1986-01-01

In this work, an improved self-cooled blanket design is conceived that seeks to minimize the induced current and pressure loss, while maintaining effective cooling and power output. Standard solutions for fully developed MHD flows in rectangular ducts are utilized to describe the magnetic pressure drop in rectangular ducts in terms of the duct aspects ratio. A newly available analytical result for developing and fully developed temperatures is utilized in determining the maximum wall temperature and outlet temperature. Based on results from rectangular ducts, improved annular-type duct designs are proposed and evaluated. The results from the rectangular duct analysis indicate reduced pressure drop and increased thermal performance for large aspect ratio (ratio of duct width in the toroidal B-field direction to width normal to B-field). An infinite aspect ratio occurs for the annular duct design and it is shown that this configuration has superior characteristics as a self-cooled blanket design concept

Emissions from small scale biomass combustion - Research needs

International Nuclear Information System (INIS)

Gustavsson, L.; Karlsson, M.L.; Larfeldt, J.; Leckner, B.

1994-01-01

Earlier investigations have shown that small scale biomass combustion leads to unacceptable emissions in the air. The most important problem is high levels of unburnt hydrocarbons. This report analyzes which are the most important reasons to these emissions and which research efforts that are necessary to increase the knowledge about the combustion processes, thereby promoting the development of environmentally feasible equipment. The following factors are defined as most crucial to emission levels: size of combustion chamber, air excess ratio, means of combustion air supply, mixing between air and fuel, transient events, and fuel quality. It is concluded that both basic and research within the area is needed. More specific, research in the form of systematic analysis of best available technology, reactor experiments, compilation of knowledge about relevant basic combustion processes, mathematical modelling as well as development of measurement techniques are called for. 15 refs, 11 figs, 1 tab

Estimates of Two-Phase Flow Parameters in the Cyclone Chamber

Directory of Open Access Journals (Sweden)

Razva Aleksandr

2016-01-01

Full Text Available It provides analysis of methods for assessing circumferential speeds distribution of pressure in the cyclone chamber. It is shown that for cylindrical chambers of less than two diameters and the inlet section of at least 0.1 square cross section the maximum peripheral speed and rate distributions circumferential speeds along the current line is not changed. Analysis of the distribution shows that the concentration of small particles that are typical for gas dedusting systems have a significant impact on the distribution of pressure, vacuum and on the axis of the absolute value decreases toward dust of output section unlike the swirl chambers fuel combustion.

Mitigating the effect of siloxanes on internal combustion engines using landfill gasses

Science.gov (United States)

Besmann, Theodore M

2014-01-21

A waste gas combustion method that includes providing a combustible fuel source, in which the combustible fuel source is composed of at least methane and siloxane gas. A sodium source or magnesium source is mixed with the combustible fuel source. Combustion of the siloxane gas of the combustible fuel source produces a silicon containing product. The sodium source or magnesium source reacts with the silicon containing product to provide a sodium containing glass or sodium containing silicate, or a magnesium containing silicate. By producing the sodium containing glass or sodium containing silicate, or the magnesium containing silicate, or magnesium source for precipitating particulate silica instead of hard coating, the method may reduce or eliminate the formation of silica deposits within the combustion chamber and the exhaust components of the internal combustion engine.

Design and testing of a combustion-heated nineteen-converter SAVTEC array

International Nuclear Information System (INIS)

Nyren, T.; Fitzpatrick, G.O.; Korringa, M.; McVey, J.; Sahines, T.

1984-01-01

The SAVTEC (Self-Adjusting Versatile Thermionic Energy Converter) is a new design approach for achieving very close (<12μ) interelectrode spacing in a thermionic converter. Techniques were developed for fabricating an array of nineteen SAVTEC converters. The array was incorporated in an SiC protective ''hot shell'' which also served as a radiant heat source for the emitter of each converter. The completed assembly was tested with a specially constructed combustion heat source. Electric output was generated by sixteen of the nineteen converters, despite poor thermal contact in a cooling block, which resulted in high collector temperatures. Details of the array design and test results are described

Numerical investigation of a straw combustion boiler – Part I: Modelling of the thermo-chemical conversion of straw

Directory of Open Access Journals (Sweden)

Dernbecher Andrea

2016-01-01

Full Text Available In the framework of a European project, a straw combustion boiler in conjunction with an organic Rankine cycle is developed. One objective of the project is the enhancement of the combustion chamber by numerical methods. A comprehensive simulation of the combustion chamber is prepared, which contains the necessary submodels for the thermo-chemical conversion of straw and for the homogeneous gas phase reactions. Part I introduces the modelling approach for the thermal decomposition of the biomass inside the fuel bed, whereas part II deals with the simulation of the gas phase reactions in the freeboard.

Fundamental and applied research on core engine/combustion noise of aircraft engines

Science.gov (United States)

Plett, E. G.; Leshner, M. D.; Summerfield, M.

1974-01-01

Some results of a study of the importance of geometrical features of the combustor to combustion roughness and resulting noise are presented. Comparison is made among a perforated can flame holder, a plane slotted flame holder and a plane slotted flame holder which introduces two counter swirling streams. The latter is found to permit the most stable, quiet combustion. Crosscorrelations between the time derivative of chamber pressure fluctuations and far field noise are found to be stronger than between the far field noise and the direct chamber pressure signal. Temperature fluctuations in the combustor nozzle are also found to have a reasonably strong crosscorrelation with far field sound.

Development of Cloud Chamber by Using Peltier Device

International Nuclear Information System (INIS)

Woo, Jong Kwan; Kwon, Jin Young; Park, Sang Tae

2011-01-01

In this research, we developed the newly cloud chamber apparatus by using Peltier device to apply nuclear physics experiment in high school or university. We observed the cosmic rays track by using the developed apparatus and a camcorder. And we compared and analyzed the acquired data. From the results, we acquired the following conclusions and suggestions : First, it is very difficult to observe the cosmic rays track in the typical cloud chamber because of the low frequency of it. But in the newly developed cloud chamber we can observe easily the cosmic rays track owing to the high frequency of it. Second, when we do the experiment with the newly developed apparatus, we found that the cosmic rays track happens well under the condition that the temperature of the upper place of cooling plate must be below 5 degree Celsius with more than isopropanol 1.04X10 -5 ml.mm -3 . Third, the newly developed apparatus will be improved to have better precision by controlling the temperature of cooling plate in the cloud chamber by current intensity. Therefore we think that it is very useful to use the newly developed apparatus in the nuclear physics experiment in high school or university.

Development of Cloud Chamber by Using Peltier Device

Energy Technology Data Exchange (ETDEWEB)

Woo, Jong Kwan [Jae Hyun High School, Seoul (Korea, Republic of); Kwon, Jin Young [Jeon Min High School, Daejeon (Korea, Republic of); Park, Sang Tae [Dept. of Physics Education, Kongju National University, Kongju (Korea, Republic of)

2011-09-15

In this research, we developed the newly cloud chamber apparatus by using Peltier device to apply nuclear physics experiment in high school or university. We observed the cosmic rays track by using the developed apparatus and a camcorder. And we compared and analyzed the acquired data. From the results, we acquired the following conclusions and suggestions : First, it is very difficult to observe the cosmic rays track in the typical cloud chamber because of the low frequency of it. But in the newly developed cloud chamber we can observe easily the cosmic rays track owing to the high frequency of it. Second, when we do the experiment with the newly developed apparatus, we found that the cosmic rays track happens well under the condition that the temperature of the upper place of cooling plate must be below 5 degree Celsius with more than isopropanol 1.04X10{sup -5}ml.mm{sup -3}. Third, the newly developed apparatus will be improved to have better precision by controlling the temperature of cooling plate in the cloud chamber by current intensity. Therefore we think that it is very useful to use the newly developed apparatus in the nuclear physics experiment in high school or university.

NUMERICAL INVESTIGATION OF THE COUPLED TURBULENT COMBUSTION-RADIATION IN AN

Directory of Open Access Journals (Sweden)

BRAHIM ZITOUNI

2017-06-01

Full Text Available A turbulent non-premixed methane-air flame was studied in an axisymmetric cylindrical combustion chamber, focusing on thermal radiation effects on temperature and soot concentration fields. The simulation is based on the solution of the mass, energy, momentum and chemical species conservation equations. The turbulence and its interaction with combustion are modelled by the standard k-ε model and eddy dissipation concept, respectively. The semiempirical model of Syed is implemented to deal with soot formation and oxidation and thus ensuring the overall efficiency of the present investigation. The radiative heat transfer is surveyed, for two cases: with and without soot radiation. The numerical resolution has been achieved using the Hottel’s zonal method and the standard weighted-sum-of-gray-gases model, to predict the real gas-soot mixture radiation effect. A new concept of optical exchange gap has been recently proposed and applied here after avoiding the singularities obviously encountered in the calculation of the direct exchange areas of volume zones self-irradiance. The obtained numerical results are compared to experimental data due to Brookes and Moss. Radiation exchange is found to noticeably affect temperature and soot volume fraction predictions and slightly the mixture fraction solutions. The present paper shows that taking into account turbulent combustion-radiation interactions leads to more accurate results by comparison to available experimental data.

Thermodynamic analysis of an absorption refrigeration system used to cool down the intake air in an Internal Combustion Engine

International Nuclear Information System (INIS)

Novella, R.; Dolz, V.; Martín, J.; Royo-Pascual, L.

2017-01-01

Highlights: • Enough power in the exhaust gases is available to operate the absorption cycle. • Three engine operating points are presented in the article. • Improvement potential up to 4% is possible in the engine indicated efficiency. • Engine indicated efficiency benefit was experimentally confirmed by direct testing. - Abstract: This paper deals with the thermodynamic analysis of an absorption refrigeration cycle used to cool down the temperature of the intake air in an Internal Combustion Engine using as a heat source the exhaust gas of the engine. The solution of ammonia-water has been selected due to the stability for a wide range of operating temperatures and pressures and the low freezing point. The effects of operating temperatures, pressures, concentrations of strong and weak solutions in the absorption refrigeration cycle were examined to achieve proper heat rejection to the ambient. Potential of increasing Internal Combustion Engine efficiency and reduce pollutant emissions was estimated by means of theoretical models and experimental tests. In order to provide boundary conditions for the absorption refrigeration cycle and to simulate its effect on engine performance, a 0D thermodynamic model was used to reproduce the engine performance when the intake air is cooled. Furthermore, a detailed experimental work was carried out to validate the results in real engine operation. Theoretical results show how the absorption refrigeration system decreases the intake air flow temperature down to a temperature around 5 °C and even lower by using the bottoming waste heat energy available in the exhaust gases in a wide range of engine operating conditions. In addition, the theoretical analysis estimates the potential of the strategy for increasing the engine indicated efficiency in levels up to 4% also at the operating conditions under evaluation. Finally, this predicted benefit in engine indicated efficiency has been experimentally confirmed by direct

Analysis Of Primary Coolant Suction Side Pressure In The Delay Chamber Of The RSG-GAS

International Nuclear Information System (INIS)

Dibyo, Sukmanto

2000-01-01

Delay chamber is a tank to delay flow that located in the primary cooling suction side of RSG-GAS. A void occurred when operation reactor caused by too high the delta P at inlet suction pump. The condition may be avoided by using one line mode of the cooling flow. The analysis show that void volume in the delay chamber is occurred because the coolant negative pressure lowers the saturation pressure should be avoided though decreasing the delta P until about 0.1 bar at about 45 exp 0 C. Solution suggested are to use bypass flow from the spent fuel to the delay chamber. Coolant temperature can be also decreased by decreasing the power level of the reactor as well as improving the heat exchanger and cooling tower performances

Cool Girls, Inc. and Self-Concept: The Role of Social Capital

Science.gov (United States)

Thomason, Jessica D.; Kuperminc, Gabriel

2014-01-01

Social capital was examined as a mediator of the association between youth development program participation and gains in self-concept in a sample of 86 primarily African American female adolescents in the Cool Girls, program, and 89 comparisons. Two dimensions of social capital (the diversity of girls' social networks and the number of life…

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

Directory of Open Access Journals (Sweden)

Qiang Zhang

2014-07-01

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

Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

Energy Technology Data Exchange (ETDEWEB)

Verma, V., E-mail: vasudha.verma@physics.uu.se [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Barbot, L.; Filliatre, P. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Hellesen, C. [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Jammes, C. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Svärd, S. Jacobsson [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

2017-07-11

Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment. - Highlights: • Studied possibility of using SPNDs as in-core detectors in SFRs. • Study done to detect local power profile changes when reactor is at nominal power. • SPND with a Pt-emitter gives measurable prompt current of the order of 600 nA/m. • Dominant proportion of prompt response is maintained throughout the operation. • Detector signal gives dynamic information on the power fluctuations.

A parametric investigation of hydrogen hcci combustion using a multi-zone model approach

International Nuclear Information System (INIS)

Komninos, N.P.; Hountalas, D.T.; Rakopoulos, C.D.

2007-01-01

The purpose of the present study is to examine the effect of various operating variables of a homogeneous charge compression ignition (HCCI) engine fueled with hydrogen, using a multi-zone model developed by the authors. The multi-zone model consists of zones, which are allotted spatial locations within the combustion chamber. The model takes into account heat transfer between the zones and the combustion chamber walls, providing a spatial temperature distribution during the closed part of the engine cycle, i.e. compression, combustion and expansion. Mass transfer between zones is also accounted for, based on the geometric configuration of the zones, and includes the flow of mass in and out of the crevice regions, represented by the crevice zone. Combustion is incorporated using chemical kinetics based on a chemical reaction mechanism for the oxidation of hydrogen. This chemical reaction mechanism also includes the reactions for nitrogen oxides formation. Using the multi-zone model a parametric investigation is conducted, in order to determine the effect of engine speed, equivalence ratio, compression ratio, inlet pressure and inlet temperature, on the performance, combustion characteristics and emissions of an HCCI engine fueled with hydrogen

Simulation and experiment for oxygen-enriched combustion engine using liquid oxygen to solidify CO2

Science.gov (United States)

Liu, Yongfeng; Jia, Xiaoshe; Pei, Pucheng; Lu, Yong; Yi, Li; Shi, Yan

2016-01-01

For capturing and recycling of CO2 in the internal combustion engine, Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle. However, due to the water spray nozzle need to be installed on the cylinder, which increases the cylinder head design difficulty and makes the combustion conditions become more complicated. In this paper, a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines. The proposed new method uses liquid oxygen to solidify part of cooled CO2 from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system. The other part of CO2 is sent to inlet system and mixed with oxygen, which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable. Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program. The effects of exhaust gas recirculation (EGR) rate are analyzed on the temperatures, the pressures and the instantaneous heat release rates when the EGR rate is more than 8%. The possibility of enclosing intake and exhaust system for engine is verified. The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO2 capture experiment is carried out. The experimental results show that when the EGR rate is 36% for the optimum EGR rate. When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min, respectively, 21.50-701.30 g dry ice is obtained. This research proposes a new design method which can capture CO2 for vehicular internal combustion engine.

Storage chamber for container of radiation-contaminated material

International Nuclear Information System (INIS)

Takakura, Masahide.

1996-01-01

The present invention concerns a storage chamber for containing radiation-contaminated materials in containing tubes and having cooling fluids circulated at the outer side of the containing tubes. The storage chamber comprises a gas supply means connected to the inside of the container tube for supplying a highly heat-conductive gas and a gas exhaustion means for discharging the gas present in the container tube. When containing vessels for radiation-contaminated materials are contained in the container tube, the gases present inside of the container tube is exhausted by means of the gas exhaustion means, and highly heat conductive gases are filled from the gas supply means to the space between the container tube and the containing vessels for the radiation-contaminated materials. When the temperature of the highly heat conductive gas is elevated due to the heat generation of the radiation-contaminated materials, the container tube is heated, and then cooled by the cooling fluid at the outer side of the container tube. In this case, the heat of the radiation-contaminated material-containing vessels is removed by the heat conduction by the highly heat conductive gas to reduce temperature gradient between the containing vessels and the containing tube. This can enhance the cooling effect. (T.M.)

Super low NO.sub.x, high efficiency, compact firetube boiler

Science.gov (United States)

Chojnacki, Dennis A.; Rabovitser, Iosif K.; Knight, Richard A.; Cygan, David F.; Korenberg, Jacob

2005-12-06

A firetube boiler furnace having two combustion sections and an in-line intermediate tubular heat transfer section between the two combustion sections and integral to the pressure vessel. This design provides a staged oxidant combustion apparatus with separate in-line combustion chambers for fuel-rich primary combustion and fuel-lean secondary combustion and sufficient cooling of the combustion products from the primary combustion such that when the secondary combustion oxidant is added in the secondary combustion stage, the NO.sub.x formation is less than 5 ppmv at 3% O.sub.2.

Design and experimental investigation of an oxy-fuel combustion system for magnetohydrodynamic power extraction

Science.gov (United States)

Hernandez, Manuel Johannes

A general consensus in the scientific and research community is the need to restrict carbon emissions in energy systems. Therefore, extensive research efforts are underway to develop the next generation of energy systems. In the field of power generation, researchers are actively investigating novel methods to produce electricity in a cleaner, efficient form. Recently, Oxy-Combustion for magnetohydrodynamic power extraction has generated significant interest, since the idea was proposed as a method for clean power generation in coal and natural gas power plants. Oxy-combustion technologies have been proposed to provide high enthalpy, electrically conductive flows for direct conversion of electricity. Direct power extraction via magnetohydrodynamics (MHD) can occur as a consequence of the motion of "seeded" combustion products in the presence of magnetic fields. However, oxy-combustion technologies for MHD power extraction has not been demonstrated in the available literature. Furthermore, there are still fundamental unexplored questions remaining, associated with this technology, for MHD power extraction. In this present study, previous magnetohydrodynamic combustion technologies and technical issues in this field were assessed to develop a new combustion system for electrically conductive flows. The research aims were to fully understand the current-state-of-the-art of open-cycle magnetohydrodynamic technologies and present new future directions and concepts. The design criteria, methodology, and technical specifications of an advanced cooled oxy-combustion technology are presented in this dissertation. The design was based on a combined analytical, empirical, and numerical approach. Analytical one-dimensional (1D) design tools initiated design construction. Design variants were analyzed and vetted against performance criteria through the application of computational fluid dynamics modeling. CFD-generated flow fields permitted insightful visualization of the

HYLIFE-II reactor chamber mechanical design: Update

International Nuclear Information System (INIS)

House, P.A.

1992-01-01

Mechanical design features of the reactor chamber for the HYLIFE-II inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams (Li 2 BeF 4 ) are used for shielding and blast protection of the chamber walls. The system is designed for a 6 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (17 m/s) salt streams and also recover up to half of the dynamic head. Cost estimates for a 1 GW e and 2 GW e reactor chamber are presented

Bending-magnet vacuum chambers for VUV ring at LNLS

International Nuclear Information System (INIS)

Castro, A.R.B. de; Rodrigues, A.R.D.; Gomes, P.A.P.; Baptista, C.A.R.

1990-01-01

We discuss design criteria dictated by optical, thermal, electrical impedance and structural considerations. The proposed chambers will provide 3 conventional light ports. A fourth port will allow extraction of back scattered soft X-rays. Cooled absorbers will collect the unused radiation while confining the photo-stimulated desorption to a vacuum antechamber away from the electron beam path. We describe the thermal considerations relating to the cooled sapphire filters needed in the visible light ports and the cooling requirements for the copper radiation absorbers. (author)

Bending-magnet vacuum chambers for VUV ring at LNLS

International Nuclear Information System (INIS)

de Castro, A.R.B.; Rodrigues, A.R.D.; Gomes, P.A.P.; Baptista, C.A.R.P.

1990-01-01

This paper discusses design criteria dictated by optical, thermal, electrical impedance and structural considerations. The proposed chambers will provide 3 conventional light ports. A fourth port will allow extraction of back scattered soft X-rays. Cooled absorbers will collect the unused radiation while confining the photo-stimulated desorption to a vacuum antechamber away from the electron beam path. The authors describe the thermal considerations relating to the cooled sapphire filters needed in the visible light ports and the cooling requirements for the copper radiation absorbers