Thermal performance of pin-fin fan-sink assemblies

Experiments are reported on the thermal performance of model fan-sink assemblies consisting of a small axial flow San which impinges air on a square array of pin-fins. Cylindrical, square, and diamond shape cross section pin-fins are considered. The pin;fin heat transfer coefficient is found to be maximum immediately under the fan blades and minimum below the fan hub and near the corners of the array. The overall heat sink thermal resistance, R, decreases with an increase in either applied pressure rise or fan power and fin height. At fixed applied pressure rise, R is minimized when the fin pitch-to-diameter ratio is maximum. At fixed fan power, R is minimized when the pitch-to-diameter ratio is reduced toward unity. Finally, cylindrical pin-fins give the best overall fan-sink performance.