Solidification of aqueous ammonium chloride in a rectangular cell under constant wall temperature - An experimental study

The effect of a binary alloy solidification process was investigated for fo ur different initial ammonium chloride concentrations (5%, 10%. 15% and 25% ) and for four different constant wall temperature conditions (-13 degreesC , -20 degreesC, -25 degreesC and -30 degreesC). The solidification process inside the test cell was interrupted at various time steps to capture the p hase front profile. Results show that a higher initial concentration and a lower constant wall temperature tend to increase the strength of thermal-dr iven buoyancy flow and solute-driven buoyancy flow respectively. The shape of both the solid and mushy phase Front profiles are affected by the streng th of these two flows. Isotherm plots and superimposed images are used to d etermine the location of solid-mush interface and mush-liquid interface res pectively, inside the test cell at any time interval. (C) 2001 Elsevier Sci ence Ltd.