Flow modeling in a DI diesel engine combustion chamber using CFD

Abstract

In the main study, the flow characteristics inside the engine cylinder equipped with three piston configurations were compared. For this, complete calculations of the intake and compression strokes were performed under realistic operating conditions and the ensemble-averaged velocity and turbulence flow fields obtained in each combustion chamber analyzed in detail. Turbulent flow field in a heavy-duty diesel engine combustion chamber has been simulated using computational fluid dynamics. Three different geometrical shapes of piston bowl were considered in the flow analysis in order to clarify the effect of combustion chamber geometry on the flow field characteristics. The first two models represent a toroidal shape (A and B), whilst the third one is simply rectangular shape of combustion chamber (C). The combustion chambers of the B and the C pistons have same bowl volume and similar bowl entry diameters, but theirs bowl shapes are quite different. The bowl volume of piston A is higher than that of the others. The simulation results showed that the bowl shapes of the combustion chambers greatly influenced the pressure, velocity and temperature distributions at the end of the compression stroke.