Micrometer-scale composite pin-fin diamond microchannel heat sink for near-10-kilowatt-level chip thermal management

This study addresses the thermal management challenge posed by heat flux densities approaching 10,000 W/cm2 in radar chip components through the novel proposal of a near-junction cooling technology utilizing diamond-based microchannel heat sinks (MHS) featuring innovative waist-shaped pin-fins coupled with cylindrical and airfoil shapes. The effects of boundary conditions and geometric dimensions on heat transfer were investigated. The results demonstrate that low mass flow rates cause heat accumulation within the microchannels, exacerbating hotspot temperature rise. While the structural parameters of the pin-fins exhibit limited impact on hotspot temperature, they significantly influence flow and heat transfer performance. To minimize irreversible losses in the heat transfer process and maximize heat transfer enhancement, the recommended parameters are an airfoil fin angle of 45°, a minor axis length of 7 μm, a distance from the origin center of 50 μm, and a waist-shaped pin-fins munber of 16. Notably, micron-scale MHS demonstrate a 33.3 % increase in the heat dissipation limit compared to millimeter-scale MHS, attributable to size effects. Furthermore, the composite pin-fins enhance heat transfer via flow acceleration and secondary flow induction. This approach achieves an unprecedented MHS heat dissipation limit of 7300 W/cm2, elevates the heat transfer coefficient to 661.6 kW/m2·K, and reduces the pressure drop to 132.4 kPa. Additionally, the total thermal resistance is reduced to 0.0059 K cm2/W, representing internationally leading performance. Future work will focus on the design of manifold MHS diamond-based structures to further elevate the heat dissipation limit while reducing thermal and flow resistance.