Effect of variation in heights of cylindrical pinfins on the thermo-hydraulic performance of an open-microchannel heat sink

Abstract

This article investigates the impact of different heights of cylindrical micropillars on the thermo-fluid properties of an open microchannel heat sink. The dimensions of the microchannel considered in this study are 0.1 mm × 0.2 mm × 10 mm. Computational fluid dynamics has been employed to simulate seven distinct microchannel layouts. These configurations are Case 1 (Closedmicrochannel with full height pinfins), Case 2 (Openmicrochannel with reduced height pinfins), Case 3 (Openmicrochannel with half height pinfins), Case 4 (Open microchannel with reduced height pinfins at upstream and half height pinfins at downstream), Case 5 (Open microchannel with reduced height pinfins at upstream and half height pinfins at downstream). Case 6 (Open microchannel with two half-height pinfins at upstream and downstream regions, respectively). Case 7 (Open microchannel with two reduced height pinfins at upstream and downstream regions, respectively). Nusselt number, pressure drop, and overall thermal performance of all the considered open configurations of microchannels are evaluated and compared with the plain and closed microchannel for the range of Reynolds number between 150 and 350 by considering water as a working fluid. The results depict that the maximum augmentation in the Nusselt number is about 16.8% achieved by the open microchannel heatsink (Case 2) corresponding to the closed microchannel (Case 1) with a reduction in pressure drop of about 7.32%. To evaluate the mutual effect of heat transfer and pressure drop, overall thermal performance is evaluated. At a lower Reynolds number, the highest performance is associated with Case 2 but at the elevated range of Reynolds number, the maximum performance is acquired by Case 4.