Bifurcated divergent microchannel heat sinks for enhanced micro-electronic cooling

Abstract

The thermal performance of microchannel heat sinks (MHSs) can be enhanced by utilizing extended surfaces such as pin fins, ribs, and bifurcation plates. Extended surfaces, however, adversely affect the hydraulic performance of the MHSs. Divergent microchannels, on the other hand, offer higher hydraulic performances but lower thermal performances than parallel microchannels. Here, bifurcated divergent MHSs are studied to examine the opposing effects of bifurcation and divergence on the thermo-hydraulic performance. Bifurcation plates with constant cross-section, variable width, and variable height are considered. Results showed that the pressure drop penalty and average heat transfer coefficient of bifurcated divergent MHSs are lower than the parallel MHSs. Considering the performance index (PI) defined as the ratio of heat transfer coefficient to pressure drop penalty, the bifurcated divergent microchannels outperform the parallel MHSs. Results also revealed that increasing the width of the bifurcation plate in the flow direction decreases the overall performance of the bifurcated divergent microchannels. The divergent bifurcation microchannels with a variable height bifurcation plate outperform the ones with a constant cross-section bifurcation plate. This study confirms the advantage of bifurcated divergent microchannels for increasing the cooling performance of the MHSs.