Numerical simulation of the EM forced flow during Sn-Pb alloy directional horizontal solidification

Abstract

This article presents a study of the influence of electromagnetically (EM) forced convection on segregation formation. As a reference case the solidification of Sn-5 wt pct Pb alloy from the Hebditch and Hunt experiment is taken. Applied forcing of convective flow is determined by the dimensionless electromagnetic forcing parameter F . The study was carried out in the range −3.5 × 10 6 < F < 3.5 × 10 6 . Velocity profiles and flow patterns in the liquid phase are obtained for different applied EM forcing conditions. As a result of parametric analysis, the dependence of the Reynolds number on the electromagnetic forcing parameter was obtained. Electromagnetic forces can significantly affect the flow in the liquid bulk, increasing and slowing down the velocity, as well as changing the circulating flow direction. Solute concentration distribution analysis has shown that EM-forced convection does not affect global solute segregation formation. For the two cases, segregation channels were obtained. However, the analysis of the global segregation index showed that an increase in the Reynolds number provokes a slight decrease in this parameter. The main mechanism of segregation formation is transport of solute rich liquid into the mushy zone. In considered numerical experiment configuration, the penetration into the mushy zone is not large, and even a change in the direction of convection in the liquid bulk does not significantly affect the mushy zone flow. The calculations were made by means of open source code in OpenFOAM and Elmer.