Phase-change materials, metals or salt hydrates, are usually subjected to subcooling at their solidification. Our present investigation is aimed at the solidification of liquid gallium. The gallium, in its liquid state, is poured into a vertical cylindrical mold, which is immersed in a cold bath. Two molds, 2 inch in diameter each, were experimented with: a polypropylene mold and a copper mold. The two were chosen due to the extreme difference in their thermal conductivity. The liquid gallium was poured into the molds through nozzles of different sizes, in order to control the rate of flow. Four thermocouple probes were mounted in each mold at different heights and radial distances. The temperatures measured by the four probes both in the polypropylene mold, and in the copper mold. In the polypropylene mold the time interval, when solidification was completed, 5-7 times bigger than in the copper mold. The present numerical study explored solidification of the poured liquid gallium by a two-dimensional (axially symmetric) model, using Fluent 6.2 software. In each case, the point of nucleation had to be known experimentally. Previous investigations in our laboratory, using other phase-change materials in a stationary state, have demonstrated that the solidified phase at the cooled boundaries adheres to the walls without cavities. Such experimental and numerical results were obtained in a spherical mold and in a cylindrical mold. However, the numerical model has closely predicted the entire process of solidification and cooling of the solid.
