Flow boiling heat transfer enhancement using carbon nanotube coatings

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.