A robust approach for numerical modeling of non-isothermal multiphase flows*

Several manufacturing processes such as casting, welding, and additive manufacturing are inherently multiphysics problems with a wide range of thermo-physical properties. These processes involve fluid flow, heat transfer, solidification/melting, and fluid-structure interaction. Numerical simulation of these multiphysics problems is quite challenging due to several length and time scales. In this presentation, we present a robust approach for the numerical modeling of non-isothermal multiphase flows with phase change. To ensure the numerical stability of the scheme in presence of high-contrasting thermo-physical properties, we consistently treat the mass, momentum, and energy transport in the conservative form of discrete equations. We combine the phase-field model with a level-set advection equation to track the solid, liquid, and gas phases in the computational domain. The proposed model discretely satisfies mass, momentum, and energy conservation, which is tested and presented in our problems. We also present results for several benchmarking cases, including the Stefan problem, melting of ice in water, and thermocapillary droplet migration in liquid metal.