Investigating Diesel Engine Performance and Emissions Using CFD

Abstract

Fluid flow in an internal combustion engine presents one of the mostchallenging fluid dynamics problems to model. This is because the flow is associatedwith large density variations. So, a detailed understanding of the flow and combustionprocesses is required to improve performance and reduce emissions without compromisingfuel economy. The simulation carried out in the present work to model DI dieselengine with bowl in piston for better understanding of the in cylinder gas motionwith details of the combustion process that are essential in evaluating the effectsof ingesting synthetic atmosphere on engine performance. This is needed for thecourse of developing a non-air recycle diesel with exhaust management system [1].A simulation was carried out using computational fluid dynamics (CFD) code FLU- ENT. Theturbulence and combustion processes are modeled with sufficient generality to includespray formation, delay period, chemical kinetics and on set of ignition. Resultsfrom the simulation compared well with that of experimental results. The model provedinvaluable in obtaining details of the in cylinder flow patterns, combustion processand combustion species during the engine cycle. The results show that the modelover predicting the maximum pressure peak by 6%, (p-θ), (p-v) diagrams for different engine loadsare predicted. Also the study shows other engine parameters captured by the simulationsuch as engine emissions, fuel mass fraction, indicated gross work, ignition delayperiod and heat release rate.