Motion and evaporation characteristics of water droplets on different heating surfaces

Anti-icing systems are crucial subsystems for ensuring aircraft safety. The movement of water droplets on protective surfaces and evaporation are common phenomena during flight. Understanding water droplets' movement and evaporation characteristics is critical to designing an effective active or passive anti-icing system. Experimental setups were conducted to investigate water droplets' motion characteristics and evaporation performance on heating surfaces with various coatings. The results indicated that the critical diameter for droplet motion was affected by surface hydrophilicity. A water droplet of th e same size could move more readily on hydrophobic surfaces. The results also revealed that the evaporation time of water droplets decreased with increasing surface hydrophilicity. This effect was more pronounced with the droplet size increase, as larger droplets exhibited higher temperature gradients than smaller droplets. The evaporation time of 6 µL water droplets on superhydrophobic coating surfaces was more than 3.5 times longer than that on hydrophilic coating surfaces. The findings of this paper reveal the mechanisms of water droplet motion and evaporation, which can benefit future anti-icing system design.