Enhanced heat transfer study of microchannel heat sink with periodically arranged triangular cavities and arc-shaped ribs

The microchannel heat sink with periodically arranged triangular cavities and arc-shaped ribs (MC-ARTC) is investigated numerically under the conditions of Reynolds number 147–736. The effects of triangular cavities and arc-shaped ribs on velocity, pressure, and temperature distribution in the channel are analyzed in comparison with a rectangular microchannel heat sink, microchannel heat sink with arc-shaped ribs, and microchannel heat sink with triangular cavities. The results show that the triangular cavity and the arc-shaped rib have important effects on the flow and heat transfer characteristics in the microchannel heat sink. Both rib and cavity can cause a change in fluid flow direction and disturb the development of the flow boundary layer. The fluid flow and heat transfer characteristics of microchannels are improved. Among the four microchannels, the MC-ARTC has the optimum comprehensive performance for the combined effect of the rib and cavity. Relative cavity width ($\beta$) and relative rib height ($\theta$) are also defined to study the effects of cavity width ($W_t$ = 89–200 μm) and rib height ($H_a$ = 8.9–28.9 μm) on the flow and heat transfer characteristics. It is found that the heat transfer of MC-ARTC is enhanced with increasing $W_t$ and $H_a$, while lead to higher pressure drop. When $\beta$ and $\theta$ are 252 and 249 μm, respectively, the comprehensive performance factor ($P_f$) of MC-ARTC reaches 1.76.