Visualization study of melting of an ice sphere in a pool of water

A unique, non-intrusive experimental method is developed to visualize the melting of ice spheres in a pool of water with possible applications of this technique to many other problems. A novel method is also devised to prepare a clear, crack-free ice sphere. Video recording and image processing help in visualizing the flow field, measuring the size of the sphere, and analyzing the change of shape from experimental data. Experiments are performed on ice spheres of three different sizes to study the effects of density anomaly on dual boundary layer behavior, one flowing upward and the other downward. The video images demonstrate asymmetry of the melting process as the ice sphere assumes an ellipsoidal profile with time, as well as the oscillatory behavior of the upward plume. The rate of melting is found to be highest at the bottom as shown by the formation of a scallop in the bottom region. It is demonstrated that a one-dimensional conduction phase-change model with constant or varying heat transfer coefficient cannot accurately predict the melting phenomena of ice.