Enhancement of boiling heat transfer on hydrophobic fluoropolymer coatings

Abstract

This paper presents results of an experimental study of the effect of hydrophobic fluoropolymer coating on the multiscale characteristics of heat transfer at water boiling. New experimental data on the dynamics of vapor bubble growth and detachment, the evolution of contact line, the nucleation site density, and heat transfer coefficient were obtained using high-speed imaging techniques, including infrared thermography and video recording from the bottom side of the transparent heater. It was shown that using a hydrophobic fluoropolymer coating leads to heat transfer enhancement, to a decrease of the surface temperature at the onset of boiling, to an increase of nucleation site density, and to significant change in the dynamics of growth and departure of vapor bubbles and the evolution of the triple contact line.