Droplet size effects on the dynamics of the impingement of an acetone droplet on a high-temperature surface

The process of the impact of an acetone droplet upon a hot flat surface is analyzed based on a 3-D numerical simulation, which considers the evaporation behavior. The 3-D level-set method is used to track the droplet surface during its deformation. The flow field within the droplet and the surrounding gas phase is solved using the finite volume method with the ALE (Arbitrary Lagrangian Eulerian) technique. The dynamic characteristics of the vapor flow are solved by a vapor flow model that accounts for the lubrication resistant effect of the vapor cushion formed by the film-boiling evaporation. The heat flux across the vapor layer and the temperature fields in all phases are determined by using a full field heat transfer model. The effects of the droplet size are illustrated in this study. The spreading and recoiling motion of the impacting droplets is compared for droplets with three different initial diameters. The extent of the droplet spreading and the residence time of the droplet on the surface both increase with an increase in the droplet size. For all cases, the heat transfer rate at the solid surface is much larger in the spreading process than that in the recoiling and rebounding processes.