Validation of a grid independent spray model and fuel chemistry mechanism for low temperature diesel combustion

Spray and combustion submodels used in a Computational Fluid Dynamics (CFD) code, KIVA-CHEMKIN, were validated for Low Temperature Combustion (LTC) in a diesel engine by comparing measured and model predicted fuel spray penetrations, and in-cylinder distributions of OH and soot. The conditions considered were long ignition delay, early and late fuel injection cases. It was found that use of a grid independent spray model, called the GASJET model, with an improved n-heptane chemistry mechanism can well predict the heat release rate, not only of the main combustion stage, but also of the cool flame stage. Additionally, the GASJET model appropriately predicts the distributions of OH and soot in the cylinder even when the resolution of the computational mesh is decreased by half, which significantly reduces the required computational time.