Flow boiling heat transfer enhancement using carbon nanotube coatings

• Published in: Applied thermal engineering 2014-04, Vol.65 (1-2), p.166-175
• Main Authors: Sujith Kumar, C.S., Suresh, S., Yang, Lezhi, Yang, Qiaqin, Aravind, S.
• Format: Article
• Language: English
• Subjects: Applied sciences; CNT coating; Critical heat flux; Diamond coating; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Flow boiling heat transfer; Heat transfer; MEMS; Mini-channel; Theoretical studies. Data and constants. Metering
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2013.12.053

In the present study, experiments are performed to understand the effect of carbon nanotubes (CNTs) and diamond coating over copper substrates on flow boiling heat transfer performance. Using de-mineralized water as the working fluid, heat transfer experiments were conducted in a mini-channel with an overall dimension of 25 × 20 × 0.4 mm. Each of the coated surfaces was tested repeatedly at different velocities to explore the dependence of heat transfer performance on parameters, especially the critical heat flux (CHF). The effect of wettability of the surface on flow boiling heat transfer was also studied. A remarkable increase in the critical heat flux was observed on CNT-coated surface when compared with bare Cu or diamond coated Cu substrate. An enhancement of 21.6% in the CHF was observed for a mass flux of 283 kg/m2 s. •Vertically aligned carbon nanotubes were coated on the copper substrate.•Diamond used as the intermediate diamond layer for improving the adhesion.•Leftward shift in boiling curve was obtained for carbon nanotube coating.•Enhancement in the critical heat flux was achieved using carbon nanotube coating.