The effects of sidewalls on pressure drop and heat transfer in a pin-finned microchannel

As a result of high specific surface area and heat transfer coefficient, microchannels incorporating micro pin-fins are promising candidates for high-power cooling systems. Four cases of in-lined circular pin-finned microchannels with different column numbers are designed in present numerical study to investigate the fluid flow and heat transfer characteristics. The Reynolds number based on the pin diameter is less than 60, corresponding to the creeping flow regime. Results show that pressure drop is proportional to the inlet velocity for all cases. At a fixed inlet velocity, pressure drop is decreased with the increase of pin-fin column number. Heat transfer coefficient of microchannel with 1 column pin-fins shows a great discrepancy of 35% at the inlet velocity of 5 m/s, while other cases have no significant differences compared to microchannel with 9 column pin-fins. The restriction of sidewalls remarkably affects the thermal-hydraulic performance of the microchannel with 1 column pin-fins; the effects of sidewalls on pressure drop and heat transfer are gradually weakened with increasing the pin-fin column number.