NUMERICAL MODELLING OF THE INTERACTION OF SPHERICAL PARTICLES WITH AN ADVANCING CONVEX SOLIDIFYING FRONT

ELIANA M. AGALIOTIS; MARIO R. ROSENBERGER; ALICIA E. ARES; CARLOS E. SCHVEZOV

Rio de Janeiro, Brasil

Conferencia; ICAM 2009 11th International Conference on Advanced Materials,; 2009

VIII Brazilian MRS Meeting. VIII Encontro SBPMat

A moving solidifing front interacts with a steady solid particle in the melt producing what is normallycalled as pushing. When the particle has a different thermal conductivity than the solid and melt the interfacecould adopt a convex or concave shape if the particle has a smaller or larger conductivity, respectively.In the present report the case of particles generating a convex interface is considered. The two mainforces acting during pushing are the drag and the pushing forces. The calculations are made in a decoupledway determining first the shape of the interface then the drag force and also the pushing force. The thermaland fluid flow fields were calculated using the finite element methods assuming the system is axi-symmetric.Both, the drag and pushing forces are integrated at each step and compared until both are equal and thesteady state of pushing is reached. The pushing force is integrated using the Casimir-Lifshitz-van der Waalsinteraction.The steady state of pushing is characterized by a separation distance between particle and interfacewhich decreases with the solidifying velocity. The results are compared with those obtained for the case ofplanar interfaces which is obtained for systems with the same thermal conductivity. As a result it is shown thereduction of equilibrium separation distance for a convex interface with respect to a planar interface whichresults in a larger solidification velocity for trapping.