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Numerical Study on Cavities Shape for the Hydrothermal Performance of Microchannel Heat Sinks with Elliptical Ribs and Secondary Channels

In order to explore the effect of the different combinations of cavities, ribs, and secondary channels on the performance and efficiency of the microchannel heat sink (MCHS), this paper numerically investigated the heat transfer and fluid flow characteristics of MCHS with different shapes of cavities, elliptic ribs, and secondary channels, where the shapes of cavities include trapezoid, fan, elliptic, elliptic rectangle and triangle, named as MC-TraS, MC-FS, MC-ES, MC-ERS, MC-TriS, respectively. The results have verified that the overall performance of all the above radiators is better than that of smooth rectangular microchannels and the shape of cavities has an important effect on the pressure drop and the average temperature of the bottom surface. More specifically, compared with other optimized structures, MC-ERS has achieved the maximum system pressure drop but the highest overall heat dissipation performance with a maximum PEC of 1.73, while the MC-TriS has the minimum comprehensive performance with a minimum PEC of 1.26. In addition, there is little difference in heat dissipation performance between MC-FS and MC-ES.