Effect of water temperature on ice melting characteristics under a bubbly flow

Icing is widespread in the waters of cold regions, affecting the movement of ships, and effective de-icing methods are very necessary. The method of de-icing under a bubbly flow has the advantage of environmental protection and low energy consumption, and the effect of water temperature as a key factor deserves to be studied. An experimental set-up is designed to explore the ice melting process at different initial water temperatures ranging from 3–9 °C. Based on the experimental results, ice morphology, melting rate, heat transfer coefficient, and ice melting efficiency are analyzed. As the ice melts, a depression appears on the ice bottom surface and the depression profile gradually stabilizes with a change ratio of less than 10 %. The depression profiles at the same normalized time during under different water temperatures are almost identical, with a difference of less than 5 %. The melting rate decreases with increasing distance from the central axis in the beginning, while that in different locations gradually decreases to an almost equal constant due to the heat insulation of the remarkable bubble as the melting proceeds. The average melting rate in the height direction is linearly related to water temperature. The heat transfer coefficient is independent of water temperature. The heat transfer coefficient at each location of the ice bottom surface will gradually approach each other as melting proceeds. The findings are expected to be meaningful in the optimization of bubble de-icing systems.