Parametric Comparison of Combustion Performance Between Two Different Piston Head Configurations for Diesel Engines using Numerical Simulations

Abstract

In the present work, a full scale computational analysis is performed inside the combustion chamber of a heavy duty industrial diesel engine for two different piston head configurations namely the Open W type and the Omega type. The complete domain is converted into a sector of 60 degrees as the combustion chamber is axi-symmetric consists of 6 nozzles located at the top centre. The extracted sector is enabled with dynamic computational grid control consisting of a baseline computational grid of 0.004 m with suitable adaptive refinements and embeddings to capture the various physical phenomena happening simultaneously inside the chamber. Appropriate physical models are set in place in order to model fuel atomization, turbulent dispersion, and air fuel mixing, evaporation, and vapourization, combustion and flame propagation. A transient simulation is performed for both the piston configurations. The two piston head configurations are compared on the basis of Indicated Mean Effective Pressure (IMEP), Mean Temperature, Integrated Heat Release, Integrated Heat Release Rate, Work Done and Emissions released for the same range of crank angles. It was found out that the performance parameters for both the piston configurations are fundamentally influenced by the fuel spray length for each of the piston type.