Effects of regular triangular prisms on thermal and hydraulic characteristics in a minichannel heat sink

Abstract

Micro/mini-channel heat sinks (MCHSs) are currently projected as an advance cooling solution for heat dissipation in the high heat flux devices. Triangular prism (TP) has a special effect on forced-convection heat transfer due to the specificity of its flow separation. To further improve the thermal performance in MCHS, this study explores the effects of regular TPs on thermal and hydraulic characteristics in a minichannel heat sink under inlet Reynolds number (Re) of 221–884 using numerical simulation. The orientation arrangement and height (Hp = 0.5–2 mm) of TP, as well as the offset value (S = 0–1.2 mm) between two adjacent TPs in the width direction of the minichannel are selected as studied parameters. The results show that the minichannel with backward triangular prism (MC-BTP, apex of TP points to outlet) performs the best heating wall temperature uniformity, highest Nusselt number (Nu) and largest friction coefficient (f). The MC-BTP also presents the greatest comprehensive performance evaluation criterion (PEC) at most of operation condition, especially at high Re. For MC-BTP, with the increase in Hp, the f increases, but the Nu and PEC increase at first and then decrease; moreover, increasing S results in the f, Nu and PEC declining. Overall, the MC-BTP with Hp = 1 mm and S = 0 yields highest PEC at most of operation condition. The friction coefficient ratio, heat transfer enhancement factor and PEC in this minichannel are in ranges of 1.45–2.22, 1.39–2.33 and 1.23–1.79, respectively. Also the maximum PEC value (1.79) is obtained at Re = 884.