Numerical Simulation of Icing Characteristics of Double Droplets Impacting on Cold Surfaces with Different Wettability

In this work, an improved solidification model based on volume of fluid (VOF) multiphase model is proposed by introducing a temperature-dependent viscosity method. The model is verified with the experimental data of a single droplet impacting and icing on the cold surface, and then applied in the study of the process of double droplets impacting on cold surfaces with different wettability. The influences of solid surface wettability, initial temperature of the droplets and impact time of the secondary droplet on droplet behavior are discussed. Simulation results show that, the impact of the secondary droplet can significantly increase the contact area between the droplet and the solid surface and reduce the restitution coefficient of the rebounded droplet in the condition of normal temperature surface without icing on the surface. However, this effect is much reduced when the droplets impact on the cold surface when ice is formed. Especially for the superhydrophobic surface, the difference of wetting factors between the single droplet impact and the double droplet impact is minor, showing that the superhydrophobic surface performs effectively in preventing icing accumulation in the case of multi-droplet impact