Study on Splash of Oil Droplets Colliding with Wall in Engine Crankcase

In the engine crankcase, the splash of oil droplets colliding with the wall has a significant impact on the formation of oil mist. In order to clarify the influencing factors of droplet impact splash, this paper establishes a calculation model of droplet impact wetting wall surface by using local mesh instantaneous refinement technology combined with volume of fluid (VOF) and wall wetting model, and verifies the reliability of the model through experiments. The results show that the thickness of oil film on the wall, the viscosity and surface tension of the oil all affect the splash behavior of oil colliding with wall. The larger the oil viscosity, the less secondary droplets produced by splashing, but the viscosity has no significant effect on the Sauter mean diameter (SMD) of secondary droplets. The bigger the surface tension of the oil, the less secondary droplets are produced, and the SMD of the secondary droplets will obviously increase. The thicker the oil film on the wall, the more secondary droplets with the larger average size produced by the splash.