Optimization of tapered pin fins for enhanced heat transfer in microchannel heat sink

Abstract

Microchannel heat sinks (MHSs) are critical components in thermal management applications, such as photovoltaic thermal (PVT) collectors, where efficient heat dissipation is essential to enhance system performance and maintain temperature stability. Despite the growing adoption of MHS, there remain research gaps concerning the optimization of pin fin geometries for improved thermohydraulic performance. This study investigates tapered-angle pin fins with angles of 15°, 20°, 25°, 30°, and 35° along with similar dissected ribs on the wall in MHS under laminar flow conditions with Reynolds numbers ranging from 100 to 900. Numerical simulations were conducted to evaluate the effects of these pin fin angles on key performance parameters: Nusselt number, friction factor, pumping power, and Thermo-hydraulic Performance Parameter (THPP). The results indicate that smaller taper angles (e.g., θ = 15°) are more effective at lower Reynolds numbers (e.g., Re = 100), achieving a Nusselt number of 9.81. However, as the flow rate increases (e.g., Re = 900), larger taper angles such as θ = 30° perform better, with the Nusselt number reaching approximately 30.62. The friction factor data reveal that larger angles, while enhancing heat transfer, also increase flow resistance, impacting the overall hydraulic efficiency. At Re = 900, the highest friction factor is observed for θ = 35° (0.191). THPP values consistently remain above 1, confirming the effectiveness of pin fin designs, with θ = 30° achieving the highest value (1.77) at Re = 900. These findings highlight the importance of selecting optimal taper angles to balance thermal performance and hydraulic efficiency, filling existing research gaps and advancing the design of MHS for PVT collectors and other high-performance applications.