Three-dimensional simulation analysis of a diesel engine using moving dynamic mesh with different turbulence and combustion models

Due to strict EPA emission regulations and declining naturally available fossil fuels, improving IC engine performance is one of the utmost priorities in automotive and railroad industries. Locomotive diesel engines are one of the major contributors of air-polluting gases like N2O, NO x, SOx and CO. Understanding the factors that affect the engine efficiency and engine exhaust composition through experimental and computational analysis may help to identify concepts to be incorporated into the operation of diesel engines. Simulation of in-cylinder gas motion will be helpful in optimizing engine design parameters to increase efficiency of the engine as well as improving engine exhaust emissions. To better understand combustion and reduce exhaust emissions in a diesel engine, an analysis of air-fuel mixing, fuel injection, combustion reaction, product formation, and heat losses in a four strokes diesel engine has been made by using a Computational Fluid Dynamics (CFD)-based simulation model. A number of different combustion models and turbulence models are also evaluated. Both 2D and 3D simulation models are considered and comparisons are made by comparing results with experiments. Results show that 3D simulation results agree reasonably well with experimental data. However, significantly high deviations are noticed between simulation results and experimental data for the simulation performed based on the Realizable k-epsilon turbulence model and the Eddy Dissipation combustion model. Further refinement of the simulation model is required using different turbulence and combustion models and comparison with additional experimental data.