A numerical investigation on the effect of shape-size-number of drills on heat transfer characteristics of a circular pin fin

An increased circuit density with digitalization and miniaturization demands a compact design for the heatsink with enhanced heat dissipation capabilities. The performance of an active air-cooled pin fin heatsink depends on the geometry of the fin, which should offer more surface area for the given volume (Compact). Providing drills in a pin fin offers a more convective surface with conduction loss, and is function of place, size, shape, and number of drills. So, this investigation is focused on studying the heat transfer characteristics of a drilled pin fin of length L and diameter D to elucidate the effect of (1) shapes; circular, elliptical, and triangular, (2) locations; L/4, L/2, and 3 L/4, (3) sizes between 0.3D and 0.5D, and (4) number; 1, 2, 4, and 6 of drills on maximum fin temperature (<i>T_max</i>) and convective resistance for differential heat inputs in different convection environments. It throws light on the possible replacement of solid fins with drilled fins for enhanced heat dissipation. It offers either more heat transfer, for the given volume with reduced weight, or decreased volume for the mandated heat load. The results demonstrated that the drill location has a mere or insignificant effect on T_max. For all the shapes considered in the study, T_max first decreases with the enlarging drill size reaches it’s minimum at 0.5D, and increases after that. The increased number of drills from 1 to 6, of size 0.5D, brings down the T_max by 20%, 20%, and 25% with circular, elliptical, and triangular drills, respectively.