Simultaneous Spreading and Solidification of an Impacting Molten Droplet With Substrate Remelting

Abstract

The nonisothermal phase-change behavior of droplet deposition on a substrate has been studied. The governing equation for the flow field is solved using a finite-volume scheme with a two-step projection method on a fixed computational grid. The volume-of-fluid (VOF) method is used to track the free surface, and the continuum surface force (CSF) method is used to model the surface tension. An enthalpy formulation with a porosity model is adopted for solving the energy equation. A comparison with published experimental findings has been done to validate the numerical model. The effects of convection terms in the energy equation are examined, and droplet spreading and solidification along with substrate remelting have been analyzed. A parametric study relating the effects of substrate preheating and impact velocity on remelting, cooling rate, spreading, and solidification has also been carried out. It has been observed that the flow field within the droplet has a significant effect on the overall deposition process.