Date of Award

Fall 2025

Document Type

Open Access Thesis

Department

Mechanical Engineering

First Advisor

Chen Li

Abstract

Modern, high-performance technology presents challenges for thermal management based on power density. To cool heat fluxes to this degree, conventional liquid-cooled heat sinks are utilized because air cooling becomes insufficient (>100 π‘Š/π‘π‘š2 ). This study introduces a hybrid heat sink that integrates liquid cooling with a dropwise-enhanced vapor chamber, contains a hermetic seal, and achieves high thermal performance with low energy consumption. The temperature hotspots, thermal resistances, gravitational/pin effects, temperature uniformity, and coefficient of performance were investigated. Experimental results demonstrate a high cooling capacity of 600 W over a 6.25 π‘π‘š2 heating area with a low cooling water flow rate of 10-25 gph. The lowest thermal resistance achieved was 0.0743 ℃/π‘Š with a hotspot temperature of 66.17℃ at 600W of dissipated heat. Integrating the dropwise condensation, via a nickelgraphene coating, lowered the hotspot temperature by 4.81β—¦C at the 0-degree orientationΒ (25 gph), and, at the 180-degree orientation, a 13.42℃ difference (25gph), which was compared to the hybrid heat sink without dropwise enhancement. Additionally, when bottom sided heating is tested, sintered mesh without pin fins demonstrated 13.2% - 15.8% gain in filmwise condensation (25-10 gph) while a 3.1% - 6.4% gain in dropwise condensation (25-10 gph) (based on thermal resistance). These results highlight the hybrid heat sink as a promising solution for next-generation electronic devices requiring high-performance cooling.

Rights

Β© 2025, Walker Ryan Champion

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