Free-surface lattice Boltzmann modeling of the impact effects of droplets on heat and solute transport in the vacuum arc remelting process

Vacuum arc remelting (VAR) is one of the mainstream methods for producing large-scale alloy ingots; however, studies on droplet impact during the VAR process remain very limited. In this study, a multiphysics coupling model based on the lattice Boltzmann method (LBM) is developed and validated using benchmark cases and benchmark experiments. The validated model is then employed to numerically investigate the effects of droplet impact on multicomponent alloy VAR processes under different melt driving forces. The results show that, under buoyancy alone, the flow intensity is weak, and droplet impact has little influence on ingot segregation. When buoyancy and self-induced Lorentz force act together, droplet impact and convection driven by the self-induced Lorentz force are aligned in the same direction, thereby enhancing solute transport and aggravating ingot segregation. In contrast, when buoyancy, self-induced Lorentz force, and stirring Lorentz force are all present, the droplet impact effect and stirring-induced convection mutually suppress each other, leading to weakened solute transport and reduced ingot segregation. This study provides new insights into VAR process research and offers a feasible numerical framework for simulating VAR processes involving gas–liquid interfaces.