Multidimensional Modeling of Temperature Distribution in Engine Combustion Chamber

2011 ◽  
Author(s):  
Yuanhong Li ◽  
Song-Charng Kong
Keyword(s):  
Heat Conduction ◽  
Combustion Chamber ◽  
Thermal Stresses ◽  
Combustion Process ◽  
Numerical Procedure ◽  
Heat Fluxes ◽  
Operating Conditions ◽  
Uniform Temperature ◽  
Temperature Distributions ◽  
Engine Combustion

Heat conduction calculations are coupled with in-cylinder combustion modeling for engine simulation in this study. Heat transfer on the fluid-solid interface will affect the in-cylinder combustion process, emissions formation, and thermal loading on the combustion chamber surface. Full knowledge of heat fluxes on the interface is important in helping improve engine efficiency, reduce exhaust emissions, and reduce combustion chamber thermal stresses. To account for the unsteady, non-uniform temperature distributions on the combustion chamber surface, a fully coupled numerical procedure was developed and applied to calculate in-cylinder flows and heat conduction in solids simultaneously. The current approach was first validated against analytical heat conduction solutions. The model was then applied to simulate diesel engine combustion under different operating conditions. Unsteady, non-uniform temperature distributions on the piston surface were successfully predicted. Global engine parameters including in-cylinder pressure, heat release rate, and emissions were also comparable to the experimental data.

Characterization of Tumble Motion in SI Engines: A New Parameter

2002 ◽  
Author(s):  
Pramod S. Mehta ◽  
M. Achuth
Keyword(s):  
Life Span ◽  
Combustion Chamber ◽  
Flow Analysis ◽  
Combustion Process ◽  
Operating Conditions ◽  
Mean Flow ◽  
Detailed Mechanism ◽  
Engine Combustion ◽  
Si Engines

A well-timed turbulence due to tumble in SI engines is found to be of substantial benefit to the engine combustion process. A mean flow analysis of tumble motion in conjunction with k-ε turbulence model has been developed to provide a detailed mechanism for turbulence enhancement due to tumble. Considering that the tumble phenomenon is highly geometry dependant, an attempt is made to relate tumble-generated turbulence to the parameters relating to intake conditions and combustion chamber geometry. Finally, a new parameter ‘vortex life span’ has been proposed to characterize tumble and its turbulence, which globally encompasses intake and combustion chamber related features. The sensitivity of this parameter is demonstrated at various operating conditions. It is found that the ‘vortex life span’ has an inverse relationship with commonly measured BDC tumble ratio and is more sensitive to the chamber geometry effects.

scholarly journals On the Turbulence-Chemistry Interaction of an HCCI Combustion Engine

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5876
Author(s):  
Marco D’Amato ◽  
Annarita Viggiano ◽  
Vinicio Magi
Keyword(s):  
Combustion Chamber ◽  
Numerical Study ◽  
Combustion Process ◽  
Operating Conditions ◽  
Chemical Mechanism ◽  
Model Parameters ◽  
Time Duration ◽  
Hcci Engine ◽  
Hcci Combustion ◽  
Engine Combustion

A numerical study was carried out to evaluate the influence of engine combustion chamber geometry and operating conditions on the performance and emissions of a homogeneous charge compression ignition (HCCI) engine. Combustion in an HCCI engine is a very complex phenomenon that is influenced by several factors that need to be controlled, such as gas temperature, heat transfer, turbulence and auto-ignition of the gas mixture. An eddy dissipation concept (EDC) combustion model was used to take into account the interaction between turbulence and chemistry. The model assumed that reactions occur in small turbulent structures called fine-scales, whose characteristic lengths and times depend mainly on the turbulence level. The model parameters were slightly modified with respect to the standard model proposed by Magnussen, to correctly simulate the characteristics of the HCCI combustion process. A reduced iso-octane chemical mechanism with 186 species and 914 chemical reactions was employed together with a sub-mechanism for NOx. The model was validated by comparing the results with available experimental data in terms of pressure and instantaneous heat release rate. Two engine chamber geometries with and without a cavity in the piston were considered, respectively. The two engines provided significant differences in terms of fluid-dynamic patterns and turbulence intensity levels in the combustion chamber. The results show that combustion started earlier and proceeded faster for the flat piston, leading to an increase in both the peak pressure and gross indicated mean effective pressure, as well as a reduction of CO and UHC emissions. An additional analysis was performed by considering a case without swirl for the flat-piston case. Such an analysis shows that the swirl motion reduces the time duration of combustion and slightly increases the gross indicated work per cycle.

scholarly journals Optimizing the Shape of a Compression-Ignition Engine Combustion Chamber by Using Simulation Tests

2019 ◽  
Vol 26 (3) ◽  
pp. 138-146
Author(s):  
Ireneusz Pielecha ◽  
Jerzy Merkisz
Keyword(s):  
Combustion Chamber ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Operating Conditions ◽  
Multidimensional Data ◽  
Compression Ignition ◽  
System Quality ◽  
Compression Ignition Engine ◽  
Engine Combustion

Abstract Modern solutions used in compression-ignition internal combustion engines are quite similar to each other. The use of high-pressure, direct fuel injection results in high combustion rates with controlled exhaust emissions. One of the combustion system quality criteria is to obtain adequately high thermodynamic indicators of the combustion process, which are obtained through, among others, the right combustion chamber geometry. Its shape influences the fuel atomization process, turbulence of fuel dose, evaporation and the combustion process. Optimizing the combustion chamber shape is one of the decisive factors proving the correct execution of the combustion process. This article presents the methodology of choosing the combustion chamber shape (changes of three selected combustion chamber dimensions) by using the optimization methods. Generating multidimensional data while maintaining the correlation structure was performed by using the Latin hypercube method. Chamber optimization was carried out by using the Nelder-Mead method. The combustion chamber shape was optimized for three engine load values (determined by the average indicated pressure) at selected engine operating conditions. The presented method of engine combustion chamber optimization can be used in low and high speed diesel propulsion engines (especially in maritime transport applications).

Analysis and Research of the Combustion Process of YN4100QB Diesel Engine

2013 ◽  
Vol 744 ◽  
pp. 35-39
Author(s):  
Lei Ming Shi ◽  
Guang Hui Jia ◽  
Zhi Fei Zhang ◽  
Zhong Ming Xu
Keyword(s):  
Diesel Engine ◽  
Internal Combustion Engine ◽  
Combustion Chamber ◽  
Optimization Design ◽  
Combustion Engine ◽  
Geometric Model ◽  
Combustion Process ◽  
Internal Combustion ◽  
Engine Combustion ◽  
Exhaust Noise

In order to obtain the foundation to the research on the Diesel Engine YN4100QB combustion process, exhaust, the optimal design of combustion chamber and the useful information for the design of exhaust muffler, the geometric model and mesh model of a type internal combustion engine are constructed by using FIRE software to analyze the working process of internal combustion engine. Exhaust noise is the main component of automobile noise in the study of controlling vehicle noise. It is primary to design a type of muffler which is good for agricultural automobile engine matching and noise reduction effect. The present car mufflers are all development means. So it is bound to cause the long cycle of product development and waste of resources. Even sometimes not only can it not reach the purpose of reducing the noise but also it leads to reduce the engine dynamic. The strength of the exhaust noise is closely related to engine combustion temperature and pressure. The calculation and initial parameters are applied to the software based on the combustion model and theory. According to the specific operation process of internal combustion engine. Five kinds of common operation condition was compiled. It is obtained for the detailed distribution parameters of combusted gas temperature pressure . It is also got for flow velocity of the fields in cylinder and given for the relation of the parameters and crankshaft angle for the further research. At the same time NOx emissions situation are got. The numerical results show that not only does it provide the 3D distribution data in different crank shaft angle inside the cylinder in the simulation of combustion process, but also it provides a basis for the engine combustion ,emission research, the optimization design of the combustion chamber and the useful information for the designs of muffler.

Effects of Fuel Nozzle Condition on Gas Turbine Combustion Chamber Exit Temperature Distributions

2010 ◽  
Author(s):  
Kristen Bishop ◽  
William Allan
Keyword(s):  
Combustion Chamber ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Operating Conditions ◽  
Spray Cone Angle ◽  
Mixing Processes ◽  
Spray Cone ◽  
Temperature Distributions ◽  
Fuel Nozzle ◽  
Exit Temperature

The effects of fuel nozzle condition on the temperature distributions experienced by the nozzle guide vanes have been investigated using an optical patternator. Average spray cone angle, symmetry, and fuel streaks were quantified. An ambient pressure and temperature combustion chamber test rig was used to capture exit temperature distributions and to determine the pattern factor. The rig tests matched representative engine operating conditions by matching Mach number, equivalence ratio, and fuel droplet size. It was observed that very small deviations (± 10° in spray cone angle) from a nominal distribution in the fuel nozzle spray pattern correlated to increases in pattern factor, apparently due to a degradation of mixing processes, which created larger regions of very high temperature core flow and smaller regions of cooler temperatures within the combustion chamber exit plane. The spray cone angle had the most measureable influence while the effects of spray roundness and streak intensity had slightly less influence. Comparisons were made with published studies conducted on the combustion chamber geometry, and recommendations were made for fuel nozzle inspections.

scholarly journals Flow field and species concentration measurements in the primary zone of an aero-engine combustion chamber

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774805
Author(s):  
Yinli Xiao ◽  
Zupeng Wang ◽  
Zhengxin Lai ◽  
Kefei Chen ◽  
Wenyan Song
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Operating Conditions ◽  
Chamber Pressure ◽  
Species Concentration ◽  
Primary Zone ◽  
Major Species ◽  
Engine Combustion ◽  
Aero Engine ◽  
Concentration Measurements

The principal features of primary zone determine the performance parameters of the whole combustion chamber, such as the pollutant emissions and combustion efficiency. In this work, flow field and major species concentration measurements are conducted in the primary zone of an aero-engine combustion chamber. The operating conditions such as air inlet temperature, chamber pressure, and air-to-fuel ratio are chosen to replicate the realistic operating conditions. The velocity field and streamlines are obtained by particle imaging velocimetry technology. The concentrations of major species are acquired by a spontaneous Raman scattering system. This article validates the feasibility of two laser diagnostic measurement techniques and presents the initial results under realistic aero-engine conditions.

Effects of Inlet Air Distortion on Gas Turbine Combustion Chamber Exit Temperature Profiles

2015 ◽  
Author(s):  
O. Maqsood ◽  
M. LaViolette ◽  
R. Woodason
Keyword(s):  
Combustion Chamber ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Temperature Profiles ◽  
Toroidal Vortex ◽  
Uniform Temperature ◽  
Sauter Mean Diameter ◽  
Test Rig ◽  
Turbine Performance ◽  
Exit Temperature

Localized damage to turbine inlet nozzles is typically caused by non-uniform temperature distributions at the combustion chamber exit. This damage results in decreased turbine performance and can lead to expensive repair or replacement. A test rig was designed and constructed for the Rolls-Royce Allison 250-C20B dual-entry combustion chamber to investigate the effects of inlet air distortion on the combustion chamber’s exit temperature fields. The rig includes a purposely built water cooled thermocouple rake to sweep the exit plane of the combustion chamber. Test rig operating conditions simulated normal engine cruise conditions by matching the quasi-non-dimensional Mach number, equivalence ratio and Sauter mean diameter. The combustion chamber was tested with an even distribution of inlet air and a 4% difference in airflow at either combustion chamber inlet. An even distribution of inlet air to the combustion chamber did not produce a uniform temperature profile and varying the inlet distribution of air exacerbated the profile’s non-uniformity. The design of the combustion chamber promoted the formation of an oval-shaped toroidal vortex inside the combustion liner, causing localized hot and cool sections separated by 90° that were apparent in the exhaust. Uneven inlet air distributions skewed the oval vortex, increasing the temperature of the hot section nearest the side with the most airflow and decreasing the temperature of the hot section on the opposite side.

Computational and Experimental Analysis of Direct CNG Injection and Mixture Formation in a Spark Ignition Research Engine

2010 ◽  
Author(s):  
Mirko Baratta ◽  
Andrea E. Catania ◽  
Francesco C. Pesce
Keyword(s):  
Numerical Model ◽  
Combustion Chamber ◽  
Cone Angle ◽  
Combustion Process ◽  
Laser Induced Fluorescence ◽  
Operating Conditions ◽  
Design Parameters ◽  
Experimental Investigations ◽  
Injection Timing ◽  
Mixture Formation

Direct injection (DI) of compressed natural gas (CNG) under high pressure conditions is a topic of great interest, owing to its potential for improving SI engine performance and fuel consumption. However, relevant technical difficulties have yet to be resolved in order to stabilize combustion process, especially for stratified engine operating conditions. The present paper is focused on experimental and numerical investigations of the jet formation and fuel-air mixing process in a research optical-access single-cylinder engine. The engine is based on the multi-cylinder engine under development within the European Community (EC) VII Framework Program (FP) InGAS Integrated Project, and features a centrally mounted poppet-valve injector on a pent-roof combustion chamber with a bowl in piston. Experimental investigations were made by means of the planar laser-induced fluorescence technique, and revealed a cycle-to-cycle jet shape variability. In particular, for specific cylinder pressure values at the start of injection, the jet can adhere to chamber walls for a relevant number of cycles, leading to an ‘umbrella-like’ shape. This can change the mixing capabilities of the combustion chamber and cause instabilities in the combustion process. The mentioned behaviour is strongly dependent not only on the injection and cylinder pressures, but also on important design parameters, such as needle cone angle and in-chamber injector protrusion. For this reason, in order to obtain a deep insight into the injected gas behaviour on an average cycle basis, the experimental investigation was supported by a numerical analysis. Simulations were carried out by an optimized variable-density finite-volume numerical model which was built within the Star-CD environment. A previously developed and validated ‘virtual injector’ model was implemented. The outcomes of the numerical model were compared to laser-induced fluorescence images, for both stratified- and homogeneous-charge engine operating conditions and a good agreement was obtained, substantiating the reliability of the applied computational model. Then, the effects of the injector protrusion in the combustion chamber and of injection timing were analyzed, and their impact on jet stability and mixture-formation process was analyzed.

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