Experimental Analysis of Droplet Impact Behavior on Aluminum Plate with Variation in Droplet Height and Surface Temperature

Aircraft icing is one of the most challenging problem that aerospace and aviation industry is facing. Over the years, research is going on to study the impact and freezing process of water droplets on cold surfaces and to subsequently devise counter measures to avoid icing. In the current work, the behavior of water droplet impacting on aluminum plate with surface roughness of 0.1 μm. The effect of droplet height variation and change in surface temperature is observed. The experiments are done at room temperature and it is found that with the increase in height, the droplet impact velocity increases, has more energy to overcome the viscous effects, and spreads more on the surface in relatively less time as compared to small heights. The droplet behavior is further studied through non-dimensional parameters. Higher Reynolds number with increase in height indicates, viscous effects are not prominent and Bond number depicts that gravity does not affect surface tension. Weber number analysis indicates that the kinetic energy is more prominent at higher heights. Then the surface temperatur is varied and experiments are performed at 0°C, -5°C, -10°C and -15°C. The results indicate that contrary to the room temperature, the viscous effects are more prominent at lower temperature and the droplet spreads less on the surface and exerts more energy in overcoming the viscous effects. The retraction rate of the droplet, after reaching the maximum spread diameter, increases with height and decreases with lower surface temperature.