Thermohydraulics of microfluidic heat sinks with pin-fins: Effect of arrangement and cross-section of the fins

• Published in: International communications in heat and mass transfer 2024-12, Vol.159, p.108026, Article 108026
• Main Authors: Patra, Chinmaya Kumar, Bhattacharya, Anandaroop, Das, Prasanta Kumar
• Format: Article
• Language: English
• Subjects: 3-D integrated circuits; Hotspot; Intra-chip cooling; Micro pin-fin; Thermal management
• ISSN: 0735-1933
• DOI: 10.1016/j.icheatmasstransfer.2024.108026

The present study evaluates the impacts of the design of a micro pin-fin (MPF) array on the thermo-hydraulics of a silicon heat sink in the presence of a hotspot over a range of heat flux values. MPFs with circular, elliptical and hexagonal cross-sections having homogeneous and heterogeneous arrangements are considered. The heat sink base centerline temperature (THS,C), total thermal resistance, maximum temperature differential (∆THS,max) and temperature uniformity index (TUI) are chosen as thermal performance indicators while pumping power is used as hydraulic performance indicator. The heterogenous MPF distribution gives the best thermal performance, maintaining maximum THS,C well below 358 K with a minimum 45.3 % reduction in ∆THS,max compared to homogeneous distribution even at the highest heat flux of the hotspot. The TUI could be maintained at 4.7 K with a moderate increase in pumping power. Fins with hexagonal cross-section exhibit the lowest thermal performance. MPFs with elliptical cross-section consume 41 % lower pumping power compared to the array with fins of circular cross-section. However, none of the fin cross-sections can ensure the best performance for all the three thermal indicators. Irrespective of the cross-section of MPFs, the thermal performance is controlled by the heat transfer rate through the fins and the size of vortex core generated, while the projected area of MPF normal to flow direction controls the hydraulic performance.