Optimization of Microchannel Heat Sink with Concave Compound Triangular Prism

To address the thermal management challenges of high-heat-flux electronic devices, this study investigates heat transfer enhancement in microchannels with composite cavity-rib triangular prism structures through numerical simulations. Three cavity configurations (arc-shaped, rectangular, and trapezoidal) with depths ranging from 0.2 to 0.35 mm were analyzed. The results reveal that increasing the cavity depth elevated the friction resistance, with the trapezoidal cavities exhibiting the highest increase in friction resistance at Re > 550. The heat transfer performance exhibited a nonlinear improvement with depth: arc-shaped cavities (D = 0.35 mm) achieved maximum Nusselt numbers at low Reynolds numbers, whereas trapezoidal cavities excelled at high Reynolds numbers. The thermal-hydraulic performance evaluation criterion (PEC) identified the arc-shaped cavity (D = 0.35 mm) as optimal, achieving a maximum PEC value of 1.7495, which surpassed the rectangular and trapezoidal configurations by 4.3% and 0.7%, respectively. This study demonstrates that composite cavity-rib structures enhance secondary flow disturbances, providing critical insights for cross-scale parameter optimization in microchannel design.