Performance improvement of high power liquid-cooled heat sink via non-uniform metal foam arrangement

The present study proposes a novel concept by employing non-uniform arrangements of metal foams alongside the heat sink applicable for liquid cooling. A total of 7 arrangements by varying PPI (pores per inch) of metal foam are made and additional 4 multiple channel designs are fabricated for comparison. Test results indicate that non-linearity term in Forchheimer equation rises significantly with increase of PPI (or with the decrease of permeability). The results suggest that the transition from the linear Darcy regime to the quadratic Forchheimer regime depends on the metal foam structure. It is also found that metal foam appreciably outperforms conventional multiple channel heat sink. The thermal resistance can be reduced by more than 62% as compared to that of empty plate design. For a given pumping power, the non-uniform arrangement of metal foam shows the best performance by employing a larger PPI metal foam at the inlet, followed by a smaller PPI metal foam, and the least PPI metal foam should be placed at the rear part of the heat sink.