Modelling the interaction of particles with a concave solidifying interface

Abstract

The interaction of a foreign particle with a solidifying interface is studied with numerical modelling. The model includes two main forces; the drag and the pushing forces. The drag force is calculated from the fluid flow, the repulsion force by the Lifshitz-Van der Waal force. The thermal field is decoupled from the force field. The model is applied to a metallic matrix and particles with similar and higher thermal conductivities; giving planar and concave interface shapes respectively. The steady state of pushing is studied for the same conditions and different solidification velocities and particle radius. The results show that a concave interface shape generates higher drag forces about one order the magnitude higher than those for a planar interface. As a result the critical velocity is less than that corresponding to a planar interface. The magnitude of the effect of the different parameters in the phenomenon is presented and discussed.