Effect of rotation on flow instabilities during solidification of a binary alloy

Abstract

Linear flow instabilities of the liquid and mushy regions during solidification of a binary alloy is investigated under a high gravity environment where the rotation axis is inclined to the high gravity vector. Results of stability analyses and numerical computations for a centrifugal mode of disturbance at several different rotation rates are determined which provide information for various flow features in the liquid and the mushy layers including neutral stability curves, streamlines and density plots for solid fraction perturbation in the mushy layer. The results indicate two distinct modes of convection whose dependences with respect to rotation rate suggest a procedure for possible elimination of chimneys formation tendency in the mushy layer. These chimneys are vertical channels of zero solid fraction and are kind of imperfections that reduce the quality of the solidified materials.