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 cro ss section pin-fins are considered. The pin;fin heat transfer coeffici ent is found to be maximum immediately under the fan blades and minimu m below the fan hub and near the corners of the array. The overall hea t sink thermal resistance, R, decreases with an increase in either app lied pressure rise or fan power and fin height. At fixed applied press ure rise, R is minimized when the fin pitch-to-diameter ratio is maxim um. At fixed fan power, R is minimized when the pitch-to-diameter rati o is reduced toward unity. Finally, cylindrical pin-fins give the best overall fan-sink performance.