Modelling primary atomization and its effects on spray characteristics under heavy duty diesel engine condition

Diesel engines are most widely used all over the world because of their efficiency, reliability and adaptability. In heavy duty engines we are more interested in the torque produced rather than the speed of an engine, such engines that are being used in the industries have low efficiency and high soot emissions due to inefficient combustion unlike high speed diesel engines that have wide commercial use. Fuel spray atomization is the key process that defines combustion efficiency, which further affects fuel economy and soot emissions. This research is focused on modelling primary atomization under several injection conditions and its effects on spray characteristics and fuel breakup under Heavy duty diesel engine conditions. The computational fluid dynamics (CFD) tools available in Ansys in which basic conservation equations of mass, momentum and energy equations are used. Fluid breakup is modelled using the new VOF-DPM Hybrid approach along with the KH breakup model. Turbulence is incorporated using Realizable kε model. Spray characteristics including penetration length, souter mean diameter (SMD),drop size distribution and drop velocity were studied, all these properties affects engine efficiency,results showed their strong dependence on injection parameters and the back pressure. The new Volume of fluid-Discrete phase model (VOF-DPM) hybrid approach proved much more effective in capturing the spray characteristics and fuel breakup.