The impact, freezing, and melting processes of a water droplet on an inclined cold surface

The present study experimentally investigated the effects of droplet size and surface temperature on the impact, freezing, and melting processes of a water droplet on an inclined cold surface. The temperature of the inclined surface was changed from room temperature 20.0 °C to −14.0 °C while water droplets of three sizes (D0 = 2.21, 2.92, and 3.31 mm) were tested. The results show that the increase of droplet size led to the increases of spreading time, spreading maximum diameter, gliding maximum diameter, and maximum displacement of foremost point. Besides, during the relaxation phase, as the decrease of surface temperature, the formost point retracted a longer distance and the spreading factor decreased more smoothly. In addition, test plate temperature was found to have an effect on the freezing time, air bubble sizes, and frost accretion. At last, the melting processes of the ice beads under different conditions were also illustrated and compared.