화학공학소재연구정보센터
Atomization and Sprays, Vol.25, No.7, 587-615, 2015
DEVELOPMENT OF AN IMPROVED SPRAY/WALL INTERACTION MODEL FOR DIESEL-LIKE SPRAY IMPINGEMENT SIMULATIONS
A new spray/wall interaction model was developed with emphasis on the simulation of diesel-like spray impingement generated by high injection pressures, which is widely used in direct-injection gasoline and diesel engines. In contrast to traditional spray/wall interaction models, lift forces were considered on the wall spray droplets in the new model, which generates a vortex at the leading edge of the wall spray instead of droplet rebound or splash. In addition, a wall-jet submodel was adopted to correct the droplet-gas relative velocity in the calculation of drag and lift forces on the droplets. Grid dependency was also significantly reduced in the new model due to the implementation of the wall-jet submodel. The wall-jet submodel was extended to cover both normal and oblique impingements, which are relevant in engines with a side-mounted injector. In the new model a new correlation was also developed to estimate the splashed mass ratio for each individual impact droplet, which provides a more accurate prediction of the overall spray impingement process. Extensive validations of the new model were performed through comparisons against measurements from a variety of diesel spray impingement experiments, instead of just using single drop or drop train impingement experiments. The results indicate that the new model matches experimental measurements very well and can be used for the prediction of spray/wall interaction, especially under the conditions relevant to modern direct-injection diesel and gasoline engines.