Numerical simulation of melting of ice heated from above

Melting of ice in a cubical enclosure partially heated from above was studied. Half of the upper surface was maintained at room temperature and the other half at 70 °C. The ice cube was maintained at its melting point at the bottom. The other side surfaces were insulated. The process was first modeled by ignoring the effect of natural convection in the liquid phase. The resulting equations of conservation of energy were solved in each phase. The motion of melting front was governed by an energy balance at the interface. This conduction model was verified by applying it to a 1-D phase change problem for which an analytical solution is available. Preliminary experiments conducted resulted in a progress of the phase front faster than that predicted by the conduction model and the interface was smoother due to strong effects of natural convection in the liquid phase, except for the initial start of melting. The model was then extended to include convective heat transfer in such a way that the liquid phase was assumed to be a mixed body subjected to natural convection from the top surface and the liquid-solid interface. The flux at the interface was obtained by finding a heat transfer coefficient for natural convection with a cold plate facing upward. The predictions of this convection model agreed well with the experimental results.