Multidimensional Numerical Simulation On Combustion Process Of4D24Diesel Engine

With the depletion of oil and the problem of environment pollution,the development of internal combustion engine is facing a more and more severe challenge,this makes the study on internal combustion engine getting more focused on combustion process in diesel engine, with the advantages of low cost, less time and effort, and intutive results, numerical simulation has become one of the main methods in the analysis of combustion process.Based on the experiment data,this dissertation made a numerical simulation on4D24diesel engine,established the simulation model and made calculation on diesel engine’s combustion process under the standard conditions by CFD software FIRE,byobserving the micro changes such as flow field and macroeconomic indicators in cylinder,madeanalyse on the factors which affect the combustion performance of diesel engine and the generation of pollutants. By the simulation calculations on combustion process under different conditions,observe and compare the results,choose the best solution from the pre-selected factors and discussed the influences on combustion process,the conclusions are as follows:(1) Higher the temperature is,the generation of nitrogen oxide is faster,the content gradually increased and become stable at last/the content of soot is first rise then fell,the maximum value appeared when temperatuesurted.(2) The fuel injection advance angle has a significantly effect on cylinder’s maximum pressure and the pollutant content in exhaust gas.With the retarding of advance angle,the content of nitrogen oxide was reduced,but themaximum pressure in cylinder decreased,at the same time the soot’s content increased hugely.(3) The nozzle height will affect the fuel’s blending in cylinder,the height should be moderate.(4) The cone angle of nozzle hole will affect the fuel’s blending position in cylinder and the oil droplets’collision position,the angle should be as large as possible.