An Approach to Automated Detection of Sessile Droplets in Mixed Convection

A method for the measurement of position and size of sessile water droplets is presented. Droplets originate from condensation on a plane vertical surface in a vented cuboidal cavity with a mixed convective flow with humid air as the working fluid. Condensation is observed through a transparent cooling device coated with polyvinyl chloride with an average contact angle of 80.0(3) \(^\circ \) . The implemented detection algorithm is based on the circle Hough Transform together with sophisticated pre- and post-processing steps, which are detailed in this work. Validation experiments yield a detection of over 97% of the area covered by droplets by detecting a minimal radius of \({13.8}\,\upmu \textrm{m}\) . Additionally, first experimental results of droplet size distributions are presented.