Spreading and evaporation of droplets at their free falling on a heated copper surface

In this work, we present the experimental results of spreading and droplet evaporation of water, NaCl and CaCl2 aqueous solutions when they freely fall on a heated copper surface. The temperature ranges of droplet evolution were determined. The time dependences of the dimensionless diameter of droplet spreading were obtained. The dependence of the temperature difference of the polished copper surface, when liquid droplets fall on it, on the surface heating temperature was experimentally determined.