Solidification of an aqueous solution in a rectangular cell with hot and cold vertical walls.

Abstract

The solidification process of aqueous sodium chloride solutions in a rectangular cell was studied experimentally and analytically. The solution, which was initially at 1°C and of 3, 5, or 10 wt% concentration, was solidified from one of the vertical walls of the cell. The other vertical wall was maintained at the initial temperature and the horizontal walls were thermally insulated. The temperature and concentration distributions, the shape of the mush-liquid interface, and the heat fluxes at the vertical walls were measured. In the analysis, the natural convection caused by the gradients of both the temperature and the concentration was calculated. The solid phase was assumed to be pure and the mushy region was not considered. It was clarified from the results of the experiments and the analyses that the growth of the high-concentration layer suppressed the natural convection in the liquid phase. The cold energy storage by the latent heat at the steady state was obtained as a function of two nondimensional variables.