Numerical analysis of various combustion chamber bowl geometries on combustion, performance, and emissions parameters in a diesel engine

Abstract

In this paper, numerical analysis of a diesel engine with various combustion chamber bowl geometries was investigated. Numerical analyses of asymmetrical bowl forms were carried out using the Ansys Forte software. Analyses were done for three different piston bowl geometries in a single-cylinder, air-cooled diesel engine at 1500 rpm engine speed. Three different bowl geometries were created, the piston-1 model is a commercial one for used engine, in the piston-2 pedestal area is removed from the piston, and in the cylindrical model bowl geometry has more straight borders. The results of the numerical study were confirmed with the results of experiments which is carried out for the piston-1 model. Simulation results showed a good correlation with experimental results. According to the results of the numerical study, the highest in-cylinder temperature was determined as 1213 K for the piston-1 model. In the piston-1 model, the combustion efficiency was improved with the increase of the swirl by the increased combustion temperature. As a result of the analysis, the thermal and combustion efficiencies of the piston-1 model were higher than the other models. The maximum turbulence velocity was observed at -12 CA for three different piston bowl models as 4.1 m/s, 4.06 m/s, and 3.9 m/s for piston-1, piston-2, and cylindrical respectively.