Abstract:To explore the impact characteristics of oil droplets impacting onto the oil film inside aero-engine bearing chamber, a three-dimensional numerical model was established using VOF (volume of fluid) method to predict the air/oil two-phase flow during the normal impact between oil droplet and deep pool. The dynamic morphologies of splashing film and cavity, and the initial characteristics of secondary oil droplets were analyzed. Subsequently the effects of droplet diameter and impact velocity were discussed in detail. The results show that the splashing film produced by the impact eventually evolves into a crown film, during which a large number of secondary droplets with different diameters are formed. An approximate hemispherical cavity is formed by the discharged oil in the pool, and the diameters of the secondary droplets satisfy a log-normal probability density function. The crown height and the cavity depth and diameter increase with the increasing droplet diameter and impact velocity. The diameter interval of secondary droplet can become more dispersed with the increasing droplet diameter and the decreasing impact velocity. Finally, the correctness and reliability of the model presented were validated by comparing with relevant experimental data.