EFFECTS OF SHAPE AND STREAMWISE SPACING OF PIN-FINS ARRAYS ON FLOW AND HEAT TRANSFER

Pin-fins are widely used to cool the trailing edge of the rotor and stator blades, which could enhance the heat transfer by increasing the heat transfer area and the turbulence intensity of cooling air. In current study, relatively large aspect ratio pin-fin arrays (the height-to-diameter ratio of the pins is 2.5) are investigated numerically through a range of Reynolds numbers between 5,000 and 50,000 to determine the effects of shape and streamwise spacing on the heat transfer augment ability and array friction factor in the channel. Staggered pin-fins of different cross-sectional shapes (circular, elliptic and teardrop) are studied in a rectangular channel with the aspect ratio of 4.8:1, and the ratio of streamwise spacing to diameter (X/d) varies from 2.0 to 3.0. Current results show that the overall performance of the elliptical-shaped pin-fin is better than the other two pin-fins, and the pins with X/d = 2.0 behave relatively better in flow and heat transfer performance when considering the variation of X/d of the elliptic pin-fin. Moreover, for the elliptical pin-fins with H/d = 2.5 in this study, Nup is less affected by streamwise spacing than Nue, and the ratio of Nup,ave/Nue,ave ranges from 1.30 to 1.65 for the elliptic pin-fins studied in this article.