Effect of Square Pin-Fin Twist on Thermo-Hydraulic Performance of a Rectangular Channel in Forced Convection

Abstract

This study dealt with an experimental/numerical investigation to manage the thermo-hydraulic performance of a heat sink with square pin-fins at various twist angles and operating conditions. An experimental test platform, which utilized low-pressure air as cooling medium, was established. Steady-state liquid crystal thermography was employed to determine the Nusselt number of the heated surface. Through numerical simulations and experiments at Re = 11400-19000, it was observed that the overall performance of rectangular channels with square pin-fins was significantly better than that of flat rectangular channels. As the Reynolds number increases, the thermal resistance of the rectangular channel with square pin-fins decreased. In addition, the Nusselt number increased with an increase of the twist angle. For large twist angles (θ = 90° and θ = 180°), the friction factor reached a minimum value at Re = 15200, while the performance factor attained a maximum value at Re = 15200. For high Reynolds number (Re = 19000) and large twist angle (θ = 180°), the cooling channel with square pin-fins demonstrated optimal heat transfer and heat dissipation effects. Furthermore, twist fins at α = 0° and α = 45° exhibited distinct local heat transfer performances within the cooling channel.

Keywords: Rectangular pin-fin, Twist angle, Thermal resistance, Pressure drop