Multidimensional Modeling and Simulation of Diesel Engine Combustion Using Multi-Pulse Injections by CFD

Due to the stringent legislation for emission of diesel engines and also increasing demand on fuel consumption the importance of detailed simulation of fuel injection, mixing and combustion have been increased in the recent years. In this research a numerical simulation is carried out on direct injection diesel engine to study the flow, combustion and emission phenomenon. In a diesel engine the flow pattern that is the turbulence inside the engine will control the combustion and thereby the emission mainly NOx, Sox and soot. So it is very important to study the flow phenomenon first before the emission study is carried. In this work an attempt is made to study the flow patterns for a cylinder design using split injection. Commercial validation tool FLUENT was used for numerical simulation. This tool solves the basic governing equations of fluid flow that is continuity, momentum, species transport and energy equation. Using finite volume method Turbulence was modeled by using standard k-ɛ model. Injection was modeled using LaGrangian approach. The reaction was modeled using non–premixed combustion which considers the effects of turbulence and detailed chemical mechanism into account to model the reaction rates. The specific heats for all the species was approximated by using piecewise polynomials. In this research simulation has been carried for triple injection and compared with experimental results and found simulation results of triple injections have shown good agreement.