Experimental study of nucleate pool boiling heat transfer of water by surface functionalization with crystalline TiO2 nanostructure

Abstract

The recent astonishing development in nanoscience created a profound space of works for state-of-the-art technology in conserving the energy by reducing the dissipation in energy conversion devices. An enhancement in boiling heat transfer is reported in this article through surface modification of Cu substrate by crystalline TiO2 nanostructure coating. The TiO2 nanostructure coating was done by electron beam evaporation technique on copper substrate at different thickness. The coated surfaces were studied by X-ray diffraction, field emission scanning electron microscopic measurement, transmission electron microscopic measurement and atomic force microscope measurement. Crystalline TiO2 nanostructure modified surfaces have been employed for the studies on nucleate pool boiling and an excellent enhancement was observed in heat transfer coefficient. The mechanism of enhancement of heat transfer coefficient in nucleate pool boiling with TiO2 nanostructure modified surface involves several effects, which includes enhancement in effective surface, facilitating generation of larger nucleation sites and enhanced surface wettability. The effect of the thickness of TiO2 nanostructure coating on heat transfer during nucleate pool boiling was extensively studied and this indicates that the boiling heat transfer coefficient increases significantly with increase of TiO2 coating thickness. The nanostructured surfaces in repeated test runs for the heat transfer process was found to remain stable with almost same heat transfer coefficient after three test runs.