NUMERICAL INVESTIGATION OF FLAT PLATE FIN HEAT SINK CONFIGURATIONS UNDER FORCED CONVECTION: A COMPARATIVE CFD STUDY

Abstract

The effectiveness of air-cooled plate-fin heat sinks is limited by the gradual buildup of the thermal boundary layer on typical flat fin surfaces, and these heat sinks are increasingly used for effective thermal control of electronic systems. In the present study, the performance of a conventional flat plate fin heat sink with three geometric modifications is systematically investigated using the three-dimensional computational fluid dynamics. The modifications include a tapered fin with a draft angle of 5 degree, a notched fin with five alternating rectangular slots, and a perforated fin with twelve circular through-holes. The base plate dimensions, fin height and fin count are same for all the four configurations. The four configurations are simulated in ANSYS Fluent 2022 R1 with realizable k-epsilon turbulence model and conjugate heat transfer with uniform velocity of 3 m/s at inlet, inlet temperature of 300 K and base heat flux of 10000 W/m2. The tapered fin yields the maximum heat transfer coefficient (169.38 W/m2K, +6.4% from the flat plate reference) and is the only Performance Evaluation Criterion over unity (PEC = 1.004) even with a 19% increase in pressure drop. The perforated and notched fins have the PECs of 0.983 and 0.962, respectively. This means that their hydraulic penalties are not completely compensated by the thermal benefits for the given geometric parameters. The temperature contour analysis shows that the notched fin has the highest peak temperature (81.1 °C) owing to the flow recirculation in the notch cavities and highly interrupted conduction channel. The results show that the tapered fin profile has the best overall thermo-hydraulic performance of all the configurations investigated and may give useful guidelines for the design of forced air-cooled electronic heat sinks.