A computational study of binary alloy solidification in the MEPHISTO experiment

A computational model is presented for the study of the solidification of a binary alloy. The enthalpy method has been modified and incorporated into both an in-house code SOLCON (Heat Transfer 98, 1998, p. 241) and the commercial CFD code CFX (CFX 4.2: Solver, 1997). The model has been used to simulate experiments on solidification of a bismuth–tin alloy which were performed during the 1997 flight of the MEPHISTO-4 experiment on the US Space Shuttle Columbia. The effects of thermal and solutal convection in the microgravity environment and of concentration-dependent melting temperature on the phase change processes are included. Comparisons of numerical solutions with actual microprobe results obtained from the MEPHISTO experiments are presented.