Robust temperature uniformity via double-layered microchannel heat sink embed thermal insulating plate

The double-layered microchannel heat sink (DL-MCHS) has been widely used due to its excellent temperature distribution uniformity and lower pressure drop, but the overall heat dissipation performance is limited by the thermal effect caused by the counterflow arrangement of the coolant. In this work, a double-layered microchannel heat sink embed thermal insulating plate (IP-DL-MCHS) is designed to mitigate the thermal effects in the microchannels, specifically reducing the impact of the coolant from the upper channel outlet on the bottom channel inlet. The new design uses thermal insulating plate to replace part of the parallel rib between the bottom channel inlet and the upper channel outlet, and a 3D solid-fluid model is established to numerically investigate its performance. Various parameters including channel length, inlet velocity, channel aspect ratio and channel pitch-width ratio on the performance of the IP-DL-MCHS are studied. The results demonstrate that compared to the DL-MCHS, the IP-DL-MCHS with appropriate thermal insulating plate length exhibits better heat dissipation performance and temperature distribution uniformity, and reaches the optimal performance as thermal insulating plate length ratio around 0.4. Additionally, the IP-DL-MCHS with thermal insulating plate length ratio of 0.4 can meet the heat dissipation requirements at the assumed critical temperature with a heat flux density of 135 W/cm2, which is 17% higher than DL-MCHS.