Numerical investigation on rebound dynamics of supercooled water droplet on cold superhydrophobic surface

The rebound dynamics of a microscale supercooled water droplet on cold superhydrophobic surface is numerically studied. A three-dimensional numerical model based on level set method and Enthalpy-Porosity model is developed to study the impacting-freezing behaviors of supercooled water droplet. The retraction rate and the morphology evolution of the supercooled water droplet are focused on. The accuracy of the adopted numerical model is validated via the well agreement with the experimental results. Four different regimes are observed for the impacting-freezing process: fully rebound, satellite rebound, breakup and fully adhesion. The numerical results indicate that the retraction rate is decreased with the cold surface temperature. The heat transfer rate between water droplet and surface is increased with the impact velocity, droplet diameter and supercooled degree of cold surface. The evolution of droplet morphology reveals the competitive relationship between droplet impact dynamics and solidification. Regarding the fully rebound regime, the rebound length increases with the Reynolds number. For the situations that rebound with satellite droplet, with the increase of the impact velocity, the generation of satellite droplet is delayed, while the size of satellite droplet is increased.