Efficient thermal management of high-heat-flux electrical/electronic components requires heat-sink designs that enhance heat transfer while limiting hydraulic penalties. In this work, a hybrid microchannel heat sink (MCHS) combining oblique grooves and a circular micro pin-fin array is investigated using three-dimensional conjugate heat transfer simulations and multi-objective Pareto optimization. The geometric variables (groove width W g , groove angle (θ), pin-fin diameter D p , and fin-region length L f ) are optimized over Re= 400–700 under a constant heat flux of 80 W/cm 2 to maximize heat-transfer enhancement and minimize pressure-drop penalty. The best Pareto designs achieve a thermo-hydraulic performance index of η= 3.91–4.24. Relative to the baseline straight-channel case (Case I), the optimized designs increase the Nusselt number by 205–290% while reducing pressure drop by 10–60%, and decrease the outlet temperature by 2.93–12.48 K across the investigated Reynolds range. Detailed flow field analysis demonstrates that the optimal geometry promotes intense secondary vortices from the oblique grooves and robust vortex shedding from the pin fins, which collectively disrupt thermal boundary layers and enhance fluid mixing. The results provide quantitative design guidance for hybrid microchannel heat sinks and indicate strong potential for compact cooling of power-dense electronic modules where thermo-hydraulic trade-offs are critical.
Gazeri et al. (Mon,) studied this question.