Electromagnetic and thermal-flow modeling of a cold-wall crucible induction melter

Abstract

An approach for modeling cold-wall crucible induction melters is described. Materials in the melt and melter are nonferromagnetic. In contrast to other modeling studies reported in the literature, the numerical models use commercial codes. The ANSYS finite-element code[1] is employed for electromagnetic field simulations and the STAR-CD finite-volume code[2] for thermal-flow calculations. Results from the electromagnetic calculations in the form of local Joule heat and Lorentz force distributions are included as source terms in the thermal-flow analysis. This loosely coupled approach is made possible by the small variation in temperature and, consequently, small variation in electrical properties across the melt as well as the quasi-steady-state nature of the thermal-flow calculations. A three-dimensional finite-element grid for electromagnetic calculations is adapted to a similar axisymmetric finite-volume grid for data transfer to the thermal-flow model. Results from the electromagnetic model compare well with operational data from a 175-mm-diameter melter. REsults from the thermal-flow simulation provide insight about molten metal circulation patterns, temperature variations, and velocity magnitudes. Initial results are included for a model that simulates the formation of a solid (skull) layer on the crucible base and wall. Overall, the modeling approach is shown to produce useful results that relate operational parameters to the physics of steady-state melter operation.