Micro pin fin heat sink design with cyclone generation instinct for hot spot mitigation

Abstract

Hot spots are locations of excessive heat flux on the microprocessor chip base due to sectional non-uniform electrical heating or localized poor heat dissipation. Mitigation of hot spot generation is one of the most critical issues in the microprocessor industry. Three novel designs of micro pin fin heat sink (MPFHS) with multiple inlets/outlets are proposed and compared with the conventional design MPFHS for that purpose. The cases studied are compared using two strategies: equal cooling fluid mass flow rate relative to MPFHS and equal average mass flux between pin fins. The MPFHS design, with multiple inlets and natural cyclone generation, achieved the highest thermo-hydraulic performance. The best design achieved 14.8 °C and 29.8 °C reductions in the maximum temperature compared to the conventional design, with equal mass flow rates for the heat sink and an average equal mass flux between pin–fin approaches. Also, the best proposed design reduces surface temperature non-uniformity by 57.1 % and 61.9 % compared to the conventional design, and improves performance against both approaches. The superior fluid dynamics of the best design are evident in the thermal performance factor, which is 1.32 and 1.38 for equal mass flow rate and equal average mass flux, respectively. The Nusselt number of the conventional design at an average mass flux of 750 kg/m2s is 9.0, whereas the best design offers a Nusselt number of 14.2 (57.3 % enhancement) for the same average mass flux using the pin–fin approach. The pressure drop behavior of the proposed best design is also experimentally verified. © 2025 Elsevier B.V., All rights reserved.