Comprehensive Study of the Effect of Ribs and Cavities on Thermal-Hydraulic Performance of Mini-Channel Heat Sinks

In this work, numerical simulations are performed to investigate the influence of combining ribs and triangular cavities on the thermal-hydraulic performance (THP) of MCHS at fluid velocities ranging from 1 to 4 m/s (corresponding to Reynolds numbers (Re) of 129.75 to 519). Specifically, the ribs are positioned on the bottom wall, and the rib width is equal to the mini-channel width, while the triangular cavities are arranged on the two side walls of the MCHS. By analyzing and comparing key parameters such as velocity distribution, streamline patterns, pressure drop, skin friction coefficient (C_f), Nusselt number (Nu), friction factor (f), temperature fields, and performance evaluation criterion (PEC), the advantages of rib-cavity coupling configuration in enhancing THP are systematically discussed. Furthermore, the effects of cavity distribution (left, middle, and right), cavity depth (0.04, 0.06, and 0.08 mm), and rib height (0.02, 0.04, and 0.06 mm) on THP are analyzed to optimize the geometric parameters of the ribs and the cavities. The numerical simulation results indicate that, in comparison to the use of ribs or cavities alone, rib-cavity coupling can further improve the THP of MCHS without causing a significant increase in pressure drop. The downstream wall of the cavity is perpendicular to the flow direction which is more favorable for enhancing the heat transfer performance. Increasing the cavity depth improves the heat transfer performance of MCHS, the maximum Nu ratio increase by 35% at a rib height of 0.06 mm. However the increase in the rib height leads to a significant increase in the pressure drop, which in turn exerts a negative impact on THP, a maximum PEC of 1.198 is obtained at a rig height of 0.02 mm. The greatest improvement in THP, reaching 19.8%, is achieved when the cavity depth is 0.08 mm and the rib height is 0.02 mm.