Influence of fin length and width on flow and heat transfer performance of miniature heat sinks

Miniature heat sinks are employed in electronic cooling applications owing to greater heat transfer characteristics and better surface-to-volume ratio. Pin fins are typically used to further enhance the thermal-hydraulic performance of such heat sinks. The present numerical investigation analyses the effect of both relative height (Hr = h/hc) as well as relative width (Wr = w/wc) of pinfin for the channel having a rectangular cross-section of 1.5 mm and 1 mm in width (wc) and height (hc) respectively while keeping the flow laminar. Five models having different Hr (0.2 to 1.0) and five models having different Wr(0.066 to 0.333) are investigated and the results are compared with the rectangular channel without fin. Findings indicate significant enhancement of thermal-hydraulic performance with increasing fin relative height as well as relative width which tends to increase flow resistance. Relative height on fins improves the Nusselt number by 11.40 %–84.81 %, while relative width increases it by 14.92 %–94.32 % for the examined range of Reynolds numbers. The microchannel that has the highest value of thermal performance factor (1.46) in the model has Hr = 0.8 and Wr = 0.333.