The Flow Resistance and Heat Transfer Characteristics of Micro Pin-Fins with Different Cross-Sectional Shapes

The flow resistance and heat transfer characteristics of deionized water flowing through a rectangular channel (60 mm x 5.2 mm x 0.5 mm) with staggered array micro pin-fin circular, diamond, and elliptical groups are experimentally investigated over Reynolds numbers ranging from 8 to 1,000, and the investigation shows that the flow resistance increases due to the endwall effect and large pin-fins density at low Re. With the increase in Re, the endwall effect is weakened, but the flow resistance still increases due to the appearance of vortex resistance, and the heat transfer is enhanced due to the flow disturbance or transition from laminar flow to turbulent flow. The experimental results are also compared with predictions of the theoretical correlations for the staggered array micro pin-fin groups, and the comparisons indicate that only the correlation related to the diamond shaped micro pin-fin groups approximately agrees with experimental data, and the other correlations do not describe well the flow and heat transfer characteristics covering laminar, transitional, and turbulent states in circular and elliptical test sections.