Estimating the volume of frozen water droplets on a cold surface during the phase change with thermal image processing

Abstract

In this paper, a new technique to estimate a frozen water droplet’s volume on a cold solid surface is presented, based on the contact angle and thermal images. The factors that can vary the contact angle, such as the temperature, surface roughness, and droplet size, are considered in the study. This technique can detect and obtain the volume of a single or a group of frozen droplets as soon as they are directly deposited on a cold hydrophilic surface and during the phase change from water to ice. The contact angle is pre-estimated, and the equivalent diameter is extracted from droplet's thermal image using image processing. From information on the contact angle and diameter of the deposited frozen droplet, the volume of the frozen droplet can be predicted. The evaluations show there is an average overestimation in droplets’ volumes of about 19%.