Study on flow and heat transfer of liquid metal in the microchannel heat sink

In order to overcome the shortcoming of high resistance of liquid metal flow, three new types of microchannel heat sinks, namely top-slotted microchannel, bottom-extension microchannel and composite microchannel are proposed, and the flow and heat transfer characteristics of liquid metal galinstan are numerically studied. It is found that all three new microchannel heat sinks can reduce the flow resistance effectively. The optimized geometric structure is obtained by analyzing the effect of geometry parameters on total thermal resistance and pump power, including the slot height, the length of extension area, the distance from the entrance to the extension point and the extension height. The lowest flow resistance is obtained in the composite microchannel and the pump power is 54.9% lower than that of the traditional channel with only 0.7% increase of total thermal resistance. Based on the geometry parameter of the slot height, the distance from the entrance to the extension point and the extension height, two factors are proposed to revise the empirical correlation of friction factor f for the top-slotted and bottom-extension channel. The corrected results are in good agreement with the numerical results.