In this research, a numerical method for simulation of droplet impact on a heated surface in the film boiling regime is proposed. In the film boiling regime, droplet evaporates immediately after impact and a vapor layer is formed between droplet and surface. In this research, the simulation model is based on the finite difference method on a staggered grid. The level set method in conjunction with the ghost fluid method is used for interface modeling. Using the ghost fluid method, discontinuity of quantities such as pressure, velocity, density and viscosity is preserved across the interface. Vaporization rate is computed using energy balance at the interface and is accurately applied in the solution process. Mesh is clustered near the surface to take into account the effect of the vapor layer in the solution process accurately. Using the presented numerical method, impacts with low and moderate Weber numbers are simulated. Comparison of results with experimental observations confirms the accuracy of the proposed model. Different stages of the impact including spreading, recoiling and rebounding are predicted accurately. Effect of various parameters such as impact velocity, impact angle and also surfactant and polymeric additives on the total heat removal is considered. Keywords Droplet impact, Film boiling, Hot surface, Level set, Ghost fluid method.
