نوع مقاله : مقاله پژوهشی
1 دانشکده فنی و مهندسی، بخش مهندسی مکانیک، دانشگاه تربیت مدرس
2 دانشکده فنی و مهندسی، بخش مهندسی مکانیک،دانشگاه تربیت مدرس
عنوان مقاله [English]
Such first order turbulence models i.e. standard k-epsilon shows a poor prediction in modeling of complex in-cylinder turbulent flows. This is mainly due to the high anisotropic turbulence effects in engine flow. Therefore, it is necessary to use the higher order turbulence model like the Reynolds Stress Model (RSM) to capture the details of the flow inside the chamber correctly. In this paper the RSM model (LRR) which was first developed by Launder, Reece and Rodi is utilized in the modeling of engine flow. We have implemented the LRR version with the assumption of nonzero mean velocity divergence to include implicitly the effects of compressibility. This model is examined in prediction of turbulence characteristics of in-cylinder flow during both compression stroke and fuel injection process. Then, Results of the RSM and k-epsilon models are compared with experimental data. Results showed that spray penetration length predicted by RSM is shorter than the one obtained by k-epsilon model. This is due to higher evaporation rate obtained from RSM compared with k-epsilon model. It is also shown that fuel vapor calculated by RSM in the combustion chamber is more widely distributed.