Session BB2.8

4:30 PM BB2.8
MODELING OF SPREADING AND SOLIDIFICATION OF MOLTEN DROPLETS ON A COLD SUBSTRATE. H. Zhang, V. Prasad, and S. Sampath, State University of New York, Center for Thermal Spray Research and Process Modeling Laboratory, Stony Brook, NY.

Several models have been developed based on deforming finite-element method with adaptive grid generation and finite difference based volume of fluid (VOF) technique to study the spreading and solidification of splat(s). Both schemes have their own advantages in modeling the spray coating processes. The deforming finite element scheme is more accurate in the tracking of the free surface and solidification interface. However, it is very difficult to handle free surface merger and separation. The phenomena of splashing can be better studied using the VOF or other capturing scheme. To alleviate these problems and build a numerical model capable of handling all aspects of spray coating process, we have developed a high-resolution numerical scheme based on finite volume front tracking method and level set formulation (LSF). This model can predict more accurately the melt/solid interface shape and its dynamics due to the use of the front tracking scheme. The contact resistance and kinetics of solidification can also be accounted for by using this scheme. The deforming shape of the splat's free surface is captured by the curvilinear level set function which is able to simulate the free surface oscillations, merger and separation. Spreading and solidification of one and two nickel droplets on a cold nickel substrate are modeled and the effect of the splat temperature, velocity, surface tension and rate of substrate cooling have been investigated. The simulation begins at the time when the molten droplet comes in contact with the substrate until the entire droplet(s) has been solidified or the deposit layer has been formed. The results have been compared with the analytical solutions of Madejski as well as with the experimental data.