ON MEASUREMENT AND PREDICTION OF THE SOLID FRACTION WITHIN MUSHY LAYERS

We present a mathematical model of a mushy layer that incorporates transport of heat and solute by the flow of interstitial fluid caused by expansion during solidification. We also reinterpret the data of Shirtcliffe et al. J. Crystal Growth 113 (1992) 566, by taking into account the anisotropy of the mushy layer, in order to determine better estimates of the local solid fraction in mushy layers produced experimentally. Very good agreement is found between the theoretical predictions and the experimental results, which suggests that certain geometrical effects that were thought to have influenced the experimental measurements may in fact be negligible.