Characteristics of boiling heat transfer on hydrophilic surface with SiO₂ coating

The paper presents the results of an experimental study of the effect of wetting properties on the local and integral characteristics of heat transfer at water boiling on the saturation line under atmospheric pressure. To control the wetting characteristics, the nanocoatings of SiO2 were synthesized on the sapphire substrate surface using various chemical methods including dip coating and spin coating. New experimental data on dynamics of vapor bubble growth and detachment, evolution of microlayer and dry spot regions, nucleation site density and bubble emission frequency, heat transfer, etc., were obtained using the high-speed imaging techniques, including infrared thermography and video recording from the bottom side of transparent heater. The analysis of experimental data on the local and integral characteristics of the boiling process made it possible to determine the mechanisms of the influence of deposited hydrophilic coatings on the heat transfer intensity.