Interaction between shrinkage-induced fluid flow and natural convection during alloy solidification

Abstract

Solidification of alloys in a two-dimensional rectangular cavity with riser is analyzed. Results for the following three cases are presented: (1) natural convection due to a temperature gradient with constant domain; (2) shrinkage-induced fluid flow with domain change; and (3) interactions between cases (1) and (2). For the alloy under study (1% Cr-steel), it is found that at the beginning and the final stage of solidification, the shrinkage-induced fluid flow is stronger than the natural convection, while in the middle stage of solidification the natural convection dominates. Also, the fluid flow caused by shrinkage in the mushy zone is more significant than that by natural convection, which implies that the shrinkage effect should be included in the modeling if the prediction of flow-related casting defects is desired.