Combining pin-fins and superhydrophobic surfaces to enhance the performance of microchannel heat sinks

Electronics cooling and thermal management presents an immense challenge to the electrification of society. From mobile devices to stationary systems, power densification of electronics platforms is putting pressureon thermal systems. This research uniquely combines superhydrophobic surfaces with pin-fin structures to investigate their combined effects on thermal performance and fluid dynamics. We examine the impact of superhydrophobic surfaces on different internal walls for both finned and non-finned microchannels. Three-dimensional finite volume method simulations are used to analyze fluid flow and heat transfer, with surface wettability modeled using a custom user-defined function. The results of the simulations were first validated against experimental data. Thermal-hydraulic performance for finned and non-finned microchannels was studied for both conventional and superhydrophobic surfaces. Superhydrophobic properties on different internal surfaces of the microchannel yielded different outcomes for finned versus non-finned designs. We show that superhydrophobic surfaces are effective in enhancing the performance of finned channels at high Reynolds number (Re). At Re = 500, finned microchannels with superhydrophobic side walls have the same performance factor ($\eta$) as a conventional microchannel without fins with a 9.4 °C lower average base surface temperature. Additionally, superhydrophobic side walls increase the pressure drop and Nusselt number by 8.9 % and 6.6 %, respectively, compared to conventional non-superhydrophobic finned surfaces. Conversely, superhydrophobic top and bottom surfaces reduce the pressure drop and Nusselt number by 13 % and 18.5 %, respectively. Our findings reveal that the location and intensity of vortices, influenced by fins, vary with different superhydrophobic surface configurations.