Thermal enhancement of microchannel heat sink using pin-fin configurations and geometric optimization

Abstract

The microchannel heat sink (MCHS) is a robust cooling technique that ensures the efficiency and reliability of compact electronic devices by dissipating a large amount of heat because of its high surface area-to-volume ratio. This study proposes a novel modification of the pin-fins geometry in MCHS, and geometric optimization using response surface methodology (RSM) to build a low thermal resistant MCHS with enhanced heat transfer efficiency with low-pressure drop. Three dimensional numerical simulations using ANSYS FLUENT 2021 R2 are performed on three pin-fins configurations, i.e., MC-BW (pins mounted transversely to the bottom wall), MC-SW (pins mounted transversely to the side wall), and MC-Mixed (pins mounted transversely to the bottom and side wall). The thermal and flow characteristics are investigated using a laminar conjugate heat transfer model at Reynolds numbers 100–1000. Results show that introducing pin-fins significantly enhances heat dissipation as it continuously breaks the boundary layer and generates flow separation downstream of the pin-fins, which enhances fluid mixing and increases heat transfer augmentation inside MCHS. Among different configurations, the MC-Mixed gives the highest improvement of 50% in the convective heat transfer coefficient at Re = 1000. The highest thermal enhancement factor of η = 1.4 is obtained for the MC-Mixed configuration at Re = 600. For the base wall pin fin configuration RSM yields optimized values of 2.50 mm, 0.25 mm, and 0.045 mm for transverse pitch, longitudinal pitch, and diameter of pin respectively, and for the mixed pin fin configuration it gives 1.0 mm, 0.150 mm, 0.035 mm and 1.250 mm values for transverse pitch, longitudinal pitch, diameter of pin and pitch of side wall pins respectively for the maximum heat transfer and minimum pressure drop.