Dynamic behavior of micrometric single water droplets impacting onto heated surfaces with TiO2 hydrophilic coating

Abstract

Dynamic behavior of micrometric single water droplets impacting onto heated surfaces with and without superhydrophilic coating is investigated using a high-speed video camera in this research study. Superhydrophilic surface coating, SHS, is achieved by coating the surface with Titanium dioxide, TiO 2, and by exposing the surface to ultraviolet, UV. Mirror heat transfer surfaces of different metals have been considered. The experimental runs are carried out by spraying single water droplets onto heated surfaces where, the droplet diameter and velocity were independently controlled. The droplet behavior during the collision with the hot surface has been observed with the high-speed video camera. By analyzing the experimental results and comparison between the present results and the results due to other investigators, the effects of surface wettability, thermal properties of the heat transfer surface, droplet velocity, droplet size and surface superheat on the dynamic behavior of micrometric single water droplets impacting onto the heated surfaces were investigated. Empirical correlations are presented describing the hydrodynamic characteristics of an individual droplet impinging onto the heated surfaces, and concealing the affecting parameters in such process. © 2013 Elsevier Masson SAS. All rights reserved.