Using radius of influence and adaptive collision mesh to capture droplet collision of a diesel engine

Abstract

The collision of fuel droplets is a vital part of diesel engines. In this work, a three-dimensional (3D) model of diesel combustion in the cylinder of a diesel engine was constructed, and the radius of influence (ROI) and adaptive collision mesh (ACM) models were used to simulate the collision behavior of the droplets. For comparison, analysis was also conducted for when the droplet collision model was not used. The impacts of the ROI and ACM models were analyzed based on the engine operating conditions, and the relevant parameters of the ROI and ACM models were modified. It was found that if the ROI model was used with different influence radius, the average Sauter mean diameter (SMD) of the diesel droplets was affected. The ROI model had a larger impact on the computational fluid dynamics calculation time than the ACM model and a smaller impact on the engine power and pollutant emissions. A large number of parcels could be used to simulate diesel spray to reduce the dependence on grids. For simulations with more parcels, the efficiency of the ACM model was much higher than that of the ROI model.