Effect of surface modification with copper nanowire arrays on nucleate boiling in a liquid cooler

This experimental study explores the enhancement of nucleate boiling heat transfer in a liquid-cooled system using copper nanowire arrays, addressing the escalating thermal demands of electronic devices. Nanowire arrays are synthesized on copper substrates by electrodeposition. The flow boiling performance is tested with nanowire arrays in the fluorinated fluid TUW-52 (boiling point: 52 °C) under subcooling degrees of 21–26 °C, Reynolds numbers of 251.4–400, and heat fluxes of 0–12.25 W cm−2. Nucleation site density increases due to the nanowire arrays, promoting bubble growth and detachment generation (bubble diameters: 0.1–0.35 mm), thus enhancing the heat transfer coefficient. The onset of nucleate boiling (ONB) temperature is reduced by 43.28 % (e.g., from 72.0 °C to 40.9 °C at Re = 316, ΔTsub = 26 °C) on the nanowire array substrate compared to a plain copper substrate, attributed to nanostructure-induced heat confinement and subcooling effects. Single-phase heat transfer performance remains comparable between the plain copper substrate and nanowire array substrate, however, the heat transfer coefficient is enhanced by 47.16 % (e.g., 5200 vs. 3530 W·m−2·K at qeff = 12.25 W cm−2) with two-phase boiling on the nanowire array substrate. The improvements stem from enhanced bubble dynamics and surface rewetting, validated by SEM analysis and repeatability tests (error <2.4 %). This work pioneers nanowire arrays in flow boiling with fluorinated fluids, offering a scalable approach for electronics cooling.