Computational analysis on thermal enhancement of a heat sink mounted with vented-roughened pin-fins

The research focuses on optimizing pin-fin heat sinks to address the challenges posed by increased circuit densities by modifying the fins. The geometry considered is a circular pin-fin heat sink of base 100 mm × 100 mm × 3 mm with fins of 10 mm diameter and 50 mm height, arranged in both inline and staggered patterns on its base. Three peripheral modifications were implemented: (1) equilateral triangular air vents, (2) roughened fin surfaces, and (3) vented-roughened (hybrid) fins. In total, eight different heat sink models were designed and simulated. Comparative studies were conducted among all. The extracted results included the local and maximum temperatures of the sink, Nusselt number, pressure loss, and the thermal enhancement factor (TEF) for varying air velocities. The findings revealed that either roughened surfaces or convective air vents significantly reduced both local and maximum temperatures for inline and staggered patterns, with the effects more pronounced at lower air velocities. Specifically, the maximum system temperature was reduced by 2°C, 8°C, and 10°C with vented, roughened, and vented-roughened surfaces, respectively, for the inline configuration. For staggered arrangement, these reductions were 9°C, 13°C, and 15°C, respectively. Replacing the conventional heat sink with a staggered-vented-roughened model resulted in a 44% increase in the Nusselt number. In addition to enhanced heat transfer, the inline configuration experienced lower pressure drops with the proposed fin modifications. Conversely, staggered configurations observed an increase in pressure drop with roughened fins and a decrease with vented fins. The TEF was calculated for all configurations and showed marginal improvements with individual modifications, reaching its maximum with hybrid surface. The enhancement was significant at lower air velocities: for hybrid fins, the TEF was 1.32 and 1.40 for inline and staggered patterns, respectively, at an air velocity of 4 m/s, and 1.09 and 1.07, respectively, at 8 m/s.