Numerical study of conjugate heat transfer in stacked microchannels

Microchannel heat sinks feature a high convective heat transfer coefficient, which is particularly beneficial to high-end electronics cooling. There are some issues to be addressed before these can be commercially implemented, among which pressure drop penalty and temperature non-uniformity are critical. Recently, a stacked microchannel heat sink has been proposed to address these two issues. Stacked microchannels provide larger flow passage, so that for a fixed heat load the required pressure drop is significantly reduced. One unique feature of the stacked microchannel heat sink is that individual layers populated with parallel microchannels can be stacked independently. As a beneficial result, flexible control over the flow direction and flow rate can be harnessed to achieve better temperature uniformity and the lowest silicon temperature. The present study conducts numerical study of heat transfer inside stacked microchannels with different flow arrangements including parallel, counter-flow, and serial. For the serial arrangement both top feeding and bottom feeding are considered. The predicted heat removal performance is compared with single layer microchannels that have the same effective flow area. It has been identified that counter-flow arrangement has the best overall performance for temperature uniformity, while parallel flow has the best performance in reducing the peak temperature. This can be explained by the detailed heat transfer information obtained through the conjugate numerical study.