On the Impact of Viscous Droplets on Wet Solid Surfaces for Spray Painting Processes

The present contribution deals with numerical studies of the impact of viscous droplets on solid surfaces, focusing especially on prewetted substrates covered with a thin liquid film during spray painting processes. Numerical simulations using the volume of fluid (VOF) approach were carried out to investigate the evolution of the shape of the impacting droplet. Both Newtonian and non-Newtonian viscous fluids were considered. The evolution of the droplet contour, especially the crater shape and size were estimated in the simulations. Effects of impact conditions and liquid properties on the crater shape and size were analyzed in detail through an appropriate parameter study.