Modeling of transport phenomena in continuous casting of non-dendritic billets

Abstract

A macroscopic model for simulating the phase change process and transport of solid fraction is developed for the case of solidification during direct chill continuous casting of a non-dendritic Al-alloy billet, in presence of electromagnetic stirring. Maxwell's equations are solved to obtain the electromagnetic force field, which is incorporated in the momentum conservation equations as body force source terms. Thereafter, the complete set of equivalent single-phase governing equations (mass, momentum, energy, species conservation and transport of solid fraction) are solved using a pressure-based finite volume method. A variable viscosity approach is employed to model fluid flow in presence of phase change. The model is first validated against some experimental and numerical results available in the literature, pertaining to the case of conventional continuous casting without any externally imposed stirring. The model predicts the temperature, velocity, species and most importantly, the solid fraction distribution in the mold. These predictions are then used for studying the influence of initial superheat, stirring intensity and cooling rate on the macroscopic behavior of the system.