Lattice Boltzmann-large eddy simulation modeling of heat transfer and solute segregation during vacuum arc remelting under an external magnetic field

Vacuum arc remelting (VAR) is essential for producing large, high-performance alloy ingots due to its effectiveness in impurity removal and segregation control. However, the influence mechanism of externally applied stirring magnetic fields (ESMF) on solute segregation during VAR remains unclear. In this study, a three-dimensional multiphysics model combining the lattice Boltzmann method (LBM) and large eddy simulation (LES) is developed to simulate the VAR process. The model couples melt flow, heat transfer, and solute transport, while electromagnetic fields are solved using electric potential and magnetic vector potential formulations. Thermophysical properties are dynamically linked to Pandat data for multicomponent alloys. The model is validated against benchmark and experimental results. Parametric studies on Ti–6Al–4V VAR under varying ESMF intensities and reversal periods reveal non-monotonic trends in flow strength, melt pool size, and macrosegregation, driven by the competition between self-induced and ESMF-driven convection. These results offer deeper insight compared to the monotonic trends reported in many experimental and numerical studies, helping to reveal the control mechanisms of ESMF in VAR. The developed model provides a feasible numerical framework for simulating the complex physical phenomena during the remelting of large alloy ingots.