Performance analysis of a mini-channel heat sink: Effects of helical screw tape inserts

This study numerically investigates the formation of longitudinal vortex flow in mini-channel heat sinks (MCHs) to improve their performance, using six novel helical screw tape structures within the channels. The study deals with single and double tapes. It focuses on the effects of changes in inner tape diameter as well as the change in the direction of helical winding. Results showed that employing helical screw tapes enhanced the MCH's performance. Across all tape structures, the MCHs with a smaller inner diameter demonstrated better thermal performance compared to their counterpart with a larger diameter; however, the hydraulic performance displayed the reverse pattern. In the Reynolds number range of 200–1000, the use of double tapes resulted in a Nusselt number enhancement of 160%–172%, which is significantly greater than the 63%–79% increase observed with single tapes. Additionally, the incorporation of double tapes with opposing helices produced a slight improvement in the Nusselt number and a considerable reduction in the Fanning friction factor compared to the utilisation of identical helices. Finally, a thermal performance criterion of 1.55 was achieved under optimal hydrothermal conditions using double tapes with opposing helices within a 1 mm inner diameter at a Reynolds number of 600.