Heat transfer enhancement of three-dimensional oscillating heat pipe based on evaporation surface hydrophilicity regulation for thermal management

Abstract

To improve the thermal management performance of high heat flux components in confined spaces, two three-dimensional oscillating heat pipes (3D-OHPs) with different adiabatic section lengths were designed in this work. 3D-OHPs with surfaces of different hydrophilicity was fabricated using alkaline-assisted oxidation technology, and the impact of surface hydrophilicity on the heat transfer performance of 3D-OHPs was investigated experimentally. The results indicated that the greater the hydrophilicity of the 3D-OHP, the better its start-up and heat transfer performance. A 3D-OHP with a shorter adiabatic section demonstrates slightly inferior start-up performance under identical hydrophilicity conditions but exhibits better overall heat transfer performance. It is also found that the 3D-OHP can initiate at 20 W under four distinct hydrophilicity conditions. Compared to the untreated 3D-OHP, the super-hydrophilic 3D-OHP reduces start-up temperature by 17.76 % and start-up time by 35.31 %. Under high-power conditions, the super-hydrophilic 3D-OHP exhibits a 37.6 % increase in thermal conductivity and a 61.5 % improvement in temperature uniformity compared to the untreated 3D-OHP. Furthermore, the thermal resistance and evaporation section temperature of the super-hydrophilic 3D-OHP are reduced by 56.69 % and 14.33 %, respectively. This study can broaden the approach to enhance the heat transfer performance of 3D-OHP and provide more application scenarios for the thermal management of power devices.