Temperature In Combustion Chamber Research Articles

Detailed Kinetic Mechanism of CNG Combustion in an IC Engine

In this study, the four kinetic reaction mechanisms were developed to simulate the formation of pollutant species in CNG fired IC engine. The reactions were generated using EXGAS and coupled with Leed’s NOx reactions to develop four kinetic mechanisms. These reaction mechanisms described the combustion of natural gas at low (below 800 K) to high (above 1000 K) temperature in combustion chamber. The simulation studies predicted that the maximum cylinder pressure was achieved up to 18.0 atm & 40.0 atm under fuel leaner conditions (φ ≈0.6) and fuel rich conditions (φ=1.13 to 1.3) respectively. The simulation based data was compared with the experimental data (when engine was operated at 3000 rpm, φ=1.0, Pinlet=0.67 atm). For fuel rich conditions, high concentrations of CO were observed while NOx levels were lowered while the fuel leaner mixture produced the lower CO emissions and moderate levels of NOx emissions. The NOx and CO profiles depicted that Mechanism-I, Mechanism-II and Mechanism III seemed to be inappropriate for predicting the emissions in due to CNG combustion IC engine. The molded data for Mechanism-IV exhibited closer agreement with experimental measurements. The rate of production analysis identified the important reactions in each mechanism which were contributing in the formation of emission concentrations of pollutant species. Although each proposed mechanism illustrated some discrepancies among the profiles, Mechanism-IV (consisting of 208 reactions and 78 species) showed good agreement with experimental data for pressure, temperature and pollutant species profiles.

Combustion chamber temperature and rate of heat release of diesel engines using rape-seed oil as fuel.

Combustion chamber temperature and rate of heat release of diesel engines using rape-seed oil as fuel.

The effects of Al 2O 3–TiO 2 coating in a diesel engine on performance and emission of corn oil methyl ester

Today, as a result of increase in oil prices, limited fossil fuel resources, environmental consideration and global warming, the methyl ester fuels have been focused on alternative fuels. Methyl ester fuels can be used more efficiently in low heat rejection engines (LHR), in which the temperature of combustion chamber is increased by creating a thermal barrier. In this study, the piston, cylinder head, exhaust and inlet valves of a diesel engine were coated with the ceramic material Al 2O 3–TiO 2 by the plasma spray method. Thus, a thermal barrier was provided for the parts of the combustion chamber with these coatings. The effects of corn oil methyl ester that produced by the transesterification method, and No. D2 fuels’ performance and exhaust emissions’ rate were studied by using equal in every respect coated and uncoated engines. Tests were performed on the uncoated engine, and then repeated on the coated engine and the results were compared. A decrease in engine power and specific fuel consumption, as well as significant improvements in exhaust gas emissions (except NOx), were observed for all test fuels used in the coated engine compared with that of the uncoated engine.

Performance and emission studies on biodiesel-liquefied petroleum gas dual fuel engine with exhaust gas recirculation

Biodiesel is an alternative fuel to diesel derived from vegetable oils by transesterification process. It can be used in diesel engines with/without any modification in the engine system. Biodiesel engines emit slightly higher NOx emissions, as compared to that of diesel engines, as higher cylinder temperatures achieved during combustion. To reduce the NOx emissions a small percentage of exhaust gases recirculated into the cylinder in dual mode operation. For the improvement of power, liquefied petroleum gas (LPG) was supplied along with fresh air in dual mode operation. This article describes experimental investigation on performance and emission characteristics of single cylinder, indirect diesel engine fueled with biodiesel-diesel blend and LPG in dual fuel mode operation with exhaust gas recirculation (EGR). Recirculation of exhaust gases into the engine decreases the combustion chamber temperatures and marginal improvement in thermal efficiency was observed with EGR. However, reduction in air flow into the engine slightly increases carbon monoxide and hydrocarbon emissions. The exhaust gas temperature of dual fuel engine with EGR is lower than that of engine without EGR.

가스엔진과 디젤엔진의 혼합 EGR시스템이 배기배출물에 미치는 영향

EGR is applied in order to lower temperature of combustion chamber by using the specific heat of carbon dioxide in engine exhaust gas. However, the problem of EGR system in diesel engine is high PM concentration. Combined EGR system can be reduced it by mixing exhaust gas of gas engine into the intake air of diesel engine. This experimental study was designed for EGR system for both engines use. The results of EGR experimental study by using diesel engine and gas engine are as follows. 1) The pressure of combustion and rate of heat release decreased. 2) The specific fuel consumption increased. But, up to middle load, it little increased. 3) NO concentration has decreased up to 50% in almost all combustion area. 4) The variation of the PM concentration at low load is not so seen. But at high load, PM increased rapidly when concentration of oxygen is decreased and most of it caused the increasing of Dry Soot.

Modelling methane-air turbulent diffusion flame in a gas turbine combustor with artifical neural network

AbstractThe present paper reports a way of using an artificial neural network (ANN) for modelling methane-air jet diffusion turbulent flame characteristics, such as temperature and chemical species mass fractions in a gas turbine combustion chamber. Since the neural network needs sets of examples to adapt its synaptic weights in the training phase, we used pre-assumed probability density function (PDF) method and considered chemical equilibrium chemistry model to compute the flame characteristics for generating the examples of input-output data sets. In this approach, flow and mixing field results are presented with a non-linear first order k-ε model. The turbulence model is applied in combination with preassumed β-PDF modelling for turbulence-chemistry interaction. The training algorithm for the neural network is based on a back-propagation supervised learning procedure, and the feed-forward multilayer network is incorporated as neural network architecture. The ability of ANN model to represent a highly non-linear system, such as a turbulent non-premixed flame is illustrated, and it can be summarized that the results of modelling of the combustion characteristics using ANN model are satisfactory, and the CPU-time and memory savings encouraging.

Incineration and gasification technologies completed with up-to-date off-gas cleaning system for meeting environmental limits

It is shown how gasification can be used for processing wastes including “waste to energy” system. First, an analysis of incineration of wastes taking into account environmental limits is performed. This analysis is aimed at a typical arrangement of a conventional oxidizing incineration plant consisting of waste storage and feeding systems, two-stage incinerator (primary and secondary combustion chambers), heat recovery system involving co-generation and off-gas cleaning system. It is also focused on a new arrangement where the primary combustion chamber (rotary kiln) is substituted by gasification reactor. The proposed concept with a fluidised bed reactor utilizes results of experimental research with various mixtures of wastes (e.g. shredded textile and rubber) considering typical conditions of operation. Experiments provide us with various important characteristics (heat value of produced syngas vs. temperature in the gasification reactor, temperature in the secondary combustion chamber vs. oxygen concentration in outlet flue gas and heat value of syngas, etc.). Then it is possible to make a comparison of conventional incineration and gasification for a concrete industrial process involving a unit for thermal treatment of hazardous industrial waste mixed with municipal solid wastes with capacity of 10,000 t/year. The application of gasification technology brings about the whole range of benefits like minimizing the consumption of auxiliary fuel and decreasing size of the secondary combustion chamber and other subsystems of the incineration plants. Involving such a system with energy and investment cost reduction into an industrial process contributes to meeting cleaner production and environmental legislation regulations.

Diagnosis analysis of a small-scale incinerator by neural networks model

The formation of PCDD/Fs (dioxins/furans) due to incomplete combustion in waste combustion process caused tremendous public concern in the last two decades. Since then, more stringent standards for combustion and emission control have been implemented for mitigating such impacts. This change resulted in shutting down many small-scale incinerators because of costly expense in retrofit for meeting higher emission standards. Yet there is still an acute need for building small-scale incinerators for the purpose of disease control, environmental sanitation, and budget saving in rural areas and remote communities. For this reason, improving the diagnosis skill that leads to identifying the optimal management strategy of those small-scale incinerators is still worthwhile to pursue. Using a neural networks model in conjunction with Garson index in this paper, the generation of a series of element contribution analyses helps to diagnose operating discrepancies and differentiate the most influential parameter tied in with the combustion process. Research findings clearly indicate that injecting the auxiliary fuel via an on/off control unit is not an ideal way, as evidenced by its relatively lower Garson index. The process control of auxiliary fuel injection system should be properly upgraded, in order to improve its handling. The results also show that the amount of waste in batch-charging mode and the lowest temperature in the primary combustion chamber during the last feeding are two critical operating factors. Controlling the charging amount per each feed to be 30 kg is a good choice to mitigate the discrepancies of the combustion process in this type of small-scale incinerator.

Simulation of truncated ideal contour nozzle separation considering external stream interactions

The multi-block computational approach is used to study the physics of shock and turbulent flow separation in the truncated ideal contour nozzle, considering the jet and external stream interactions. The code employs a fully implicit finite volume, lower—upper symmetric successive overreaction scheme with van Leer flux vector splitting using monotone upstream-centred schemes for conservation law technique to get a higher-order spatial accuracy for the total variation diminishing property. Several combustion-chamber-to-ambient pressure ratios at surrounding Mach range from 0.5 to 1.2 for both cold and hot gases are investigated to study their effects on the wall pressure, the separation point, and the thrust force. It is observed that although the flight Mach number and ambient pressure decrements delay the separation and raise the specific impulse, the combustion chamber temperature has a reverse effect on the separation point. Crisscrossing (or diamond-shaped) shock waves in the supersonic exit jet enforce the compressible flow properties to oscillate because of the external jet and ambient flow interactions. These oscillations are damped effectively by viscous and turbulent dissipations as one goes farther from the jet centreline and/or moves downstream. The position of separation point, oblique shock, and lambda shock structure angles are compared rigorously with experimental data of a two-dimensional convergent—divergent nozzle, and reasonable agreements are achieved.

Combustion Chamber Steam Injection for Gas Turbine Performance Improvement During High Ambient Temperature Operations

The gas turbines are generally used for large scale power generation. The basic gas turbine cycle has low thermal efficiency, which decreases in the hard climatic conditions of operation, so the cycles with thermodynamic improvement is found to be necessary. Among several methods shown their success in increasing the performances, the steam injected gas turbine cycle (STIG) consists of introducing a high amount of steam at various points in the cycle. The main purpose of the present work is to improve the principal characteristics of gas turbine used under hard condition of temperature in Algerian Sahara by injecting steam in the combustion chamber. The suggested method has been studied and compared to a simple cycle. Efficiency, however, is held constant when the ambient temperature increases from ISO conditions to 50°C. Computer program has been developed for various gas turbine processes including the effects of ambient temperature, pressure ratio, injection parameters, standard temperature, and combustion chamber temperature with and without steam injection. Data from the performance testing of an industrial gas turbine, computer model, and theoretical study are used to check the validity of the proposed model. The comparison of the predicted results to the test data is in good agreement. Starting from the advantages, we recommend the use of this method in the industry of hydrocarbons. This study can be contributed for experimental tests.

Oxygen-enriched air for co-incineration of organic sludges with municipal solid waste: A pilot plant experiment

Pilot-plant experiments were performed to evaluate the effect of oxygen enrichment on the co-incineration of MSW and organic sludge from a wastewater treatment facility. Combustion chamber temperatures, stack gas concentrations, i.e., CO(2) and CO, and the residual oxygen were measured. The maximum ratio of organic sludge waste to total waste input was 30 wt.%. Oxygen-enriched air, 22 vol.% (dry basis) oxygen, was used for stable combustion. As the co-incineration ratio of the sludge increased, the primary and secondary combustion chamber temperatures were decreased to 900 and 750 degrees C, respectively, approximately 100 degrees C below the proper incineration. However, if the supplied air was enriched with 22 vol.% (dry basis) oxygen content, the incinerator temperature was high enough to burn the waste mixture containing 30 wt.% moisture sludge, with an estimated heating value of 6.72 MJ/kg. There are two main benefits of using oxygen enrichment in the co-incineration. First, the sensible heat can be reduced as the quantity of nitrogen in the flue gas will be decreased. Second, the unburned carbon formation is reduced due to the oxygen-enriched burning of the waste, despite an increase in the sludge co-incineration ratio.

Study on Characteristics of Auto-ignition and Combustion in Hydrogen Jet with a Rapid Compression and Expansion Machine

Hydrogen has a potential alternative to conventional hydrocarbon fuels, because no CO2 is emitted followed by combustion and it is able to make it by electroanalysis of water. This study aims to obtain stable ignition timing and combustion processes of hydrogen when it is applied into the direct-injection diesel engine. This report, it thought about the influence of the ambient conditions on the auto-ignition and combustion behavior of the hydrogen jet was investigated with a rapid compression and expansion machine (RCEM). First, the ambient temperature in combustion chamber is raised by adding argon into the ambient gas. Second, that is raised through the oxidation process of lean DME mixture. In addition, the effect of intermediates of DME reaction on the autoignition of hydrogen jet was investigated by use of CHEMKIN III code. Moreover, this effect was experimentally clarified.

Parametric simulation of steam injected gas turbine combined cycle

In the current work, thermodynamic analysis has been conducted for a steam injected gas turbine (STIG) in the combined cycle system with the dual pressure heat-recovery steam generator. Effect of operating variables such as low-pressure (LP) steam temperature ratio, steam reheat pressure ratio, steam turbine inlet pressure, gas cycle pressure ratio and combustion chamber temperature on the efficiency of the combined cycle has been investigated. Exergy efficiency of the cycle is compared with and without the steam injection with respect to the above-mentioned parameters. Maximum mass ratio of steam injection to fuel has been examined as 6 kg/kg fuel with the complete combustion of the fuel due to excess air supply in the combustion chamber and gas reheater. Results are plotted from the case of without steam injection to the maximum possible steam ratio. LP temperature ratio is identified as a dominant parameter having impact on the efficiency of the combined cycle as the steam is injected at this pressure. Component exergetic losses of the combined cycle as a fraction of exergy of fuel are compared with and without the steam injection. The results showed that the major exergetic loss in the combustion chamber decreased with the steam injection.

횡단류에 분사되는 액체 제트의 분무 및 연소 특성

The spray and combustion characteristics of liquid jet in cross flow with variation of injection angle are numerically studied. Numerical analysis was carried out using KIVA code, which may be used to generate numerical solutions to spray and chemical reactive fluid problem in three space dimensions and modified to be suitable for simulating liquid jet ejected into the cross flow. Wave model and KelvinHelmholtz(KH) /Rayleigh-Taylor(RT) hybrid model were used for the purpose of analyzing liquid column, ligament, and the breakup of droplet. Penetration length increases as flow velocity decreases and injection velocity increases. Numerical error increases as inflow velocity increases. The results of flame propagation contour in combustion chamber and local temperature distribution, combustion emissions were obtained.

Rocket Propellant Characteristics of Silanes/O2

We present a theoretical analysis of the applicability of various silicon hydrides (silanes) as rocket propellants. Thermodynamic data sets for 12 different silanes ranging from monosilane SiH4 to pentasilane Si5H12 were generated based on existing data. They were derived from empirically corrected thermochemical ab initio calculations and used in conjunction with the well-known computer packages NASA CEA2 and CHEMKIN to calculate equilibrium compositions and rocket performance indices. The thermodynamic datasets are now publicly available online for future calculations. Chemical equilibrium combustion compositions and adiabatic flame temperatures in rocket combustion chambers and the specific impulses at the nozzle exit assuming shifting equilibrium were calculated for several silane fuels using oxygen as oxidizer. The computational results created by CEA2 and CHEMKIN are in very good agreement to each other and are compared to conventional fuels such as liquid hydrogen (LH), hydrocarbons and hydrazines. Compared to alkane fuels, the combustion of silanes with oxygen-despite the much higher average molecular mass of the combustion products-results in similar maximum specific impulses and adiabatic flame temperatures due to the high positive values of the heats of formation of the silanes, indicating that silanes may be interesting candidates as rocket propulsion fuels.

EFFECT OF COMBUSTION CHAMBER'S WALL TEMPERATURE IN TRANSIENT CONDITIONS ON COMBUSTION NOISE OF INTERNAL COMBUSTION ENGINE

Study the effect of combustion chamber's temperature in transient conditions on combustion noise mechanism of DI-Diesel engines. By developing testing technique and method of transient conditions and studying the difference of combustion chamber's wall temperature between transient conditions and steady conditions, the different combustion noise mechanism between transient conditions and steady conditions is analyzed from the point of aerodynamic load and high-frequency oscillation of combustion pressure. The combustion chamber's wall temperature in transient conditions is higher than steady conditions in the same load and at the same rotation speed. It results in the changing of ignition delay in two conditions and affects the combustion pressure, rate of pressure rise, frequency and amplitude of the high-frequency oscillation of combustion pressure. The result shows that the difference of combustion chamber's wall temperature between transient and steady conditions in the same load and at the same rotation speed affects the dynamic load and high-frequency oscillation of combustion noise. It is one of the important second level factors resulting in the difference of combustion noise in two conditions.

C113 赤外カメラによる点火プラグの温度計測

The technique to measure spark plug temperature in an engine combustion chamber was developed. As for this technique, the infrared image of a spark plug in a visualization engine is captured with an IR camera. The visualization window which stands up to the environment of the combustion chamber which reaches 100 atm and 2000°C is attached, and this technology can measure a plug temperature to drive in the high load. Furthermore, this technology can measure a change in plug temperature in every cycle.

A Study of the Heat Flux on Combustion Chamber in Diesel Engines

Maintenance and inspection work during operation for the low speed diesel engines have to be minimized to rationalize the work and reduce the maintenance cost. For higher reliability and automatic surveillance, the detection of abnormal conditions and diagnosis of troubles have become necessary for engines.This study analyses the temperature of combustion chamber of the low speed diesel engine at simulated operation. The heat flux inside the combustion chamber rises up suddenly at severe conditions of operation, and that results in the abnormal temperature change, especially at piston, piston ring and cylinder liner. The temperature distribution is estimated by calculations and analyzed by finite element method (FEM) . Time-aging effect of diesel engines raises heat flux on combustion chamber to the trouble of engines.

In Situ Measurement of Average Surface Temperature of a Diesel Engine's Combustion Chamber

In Situ Measurement of Average Surface Temperature of a Diesel Engine's Combustion Chamber

Computer simulation of the new ring seal coaction in combustion engine

A computer simulation which as model loads uses program KIVA 3 for combustion engine work process (combustion chamber heat flux, pressure and temperature) computations has been developed. It makes it possible to compute the pressure and temperature distributions and the motion of the charge in the combustion chamber at a particular point in the work cycle. Computer models of the ring seal components were constructed using computer code Parasolid v. 11. The models render to the finest detail the design‐material features of the ring seal components. The Nastran program was used to perform FEM computations for a selected point of engine work (at a crank angle of 10°) at which the maximum averaged temperatures and pressures were found to occur in the combustion chamber. Finally, 3D temperature and pressure distributions for the whole ring seal were obtained. On their basis, inferences can be made about the design‐technological nature of the seal under development.