A comparison between cooling performances of water-based and gallium-based micro-channel heat sinks with the same dimensions

Liquid metals are very attractive coolants for micro-channel heat sinks with a high heat flux. However, whether liquid metals can achieve a better cooling performance than water in micro-channel heat sinks of the same dimensions has not been fully investigated so far. In the present work, we compared the cooling performances between liquid gallium and water in terms of total thermal resistances of the micro-channel heat sinks. Single-variable study was first carried out and the critical values of geometrical parameters were obtained, under which the micro-channel heat sinks have the same total thermal resistance adopting water or liquid gallium as coolant. Then, multi-variable study was conducted, based on which the 3-D feasible regions (in which liquid gallium has a better cooling performance than water) were plotted in the channel width-fin width-channel height diagram. Finally, for clarity the 3-D feasible regions were transformed into 2-D ones in the channel width-fin width diagram. The overall movement and area change of the 2-D feasible region were investigated by varying one of the geometrical or operational parameters. The results obtained in this work can provide guidance for the design of micro-channel heat sinks employing liquid metals as coolant.