Enhancement of the anti-icing performance by surface modification during droplet impact on subcooled surfaces

Icing phenomena during droplet impact on subcooled surfaces frequently cause economic losses and safety problems in industry. In this paper, the processes of droplet impact on subcooled flat surfaces were experimentally studied by high-speed camera technique. The results indicated that increases in Weber number (We) and surface subcooling (ΔT) were unfavorable to anti-icing on the copper surface. This was caused by shortening the icing delay time and icing time, while increasing the icing diameter. The connection between icing morphology and icing characteristics was established. Through surface modification, the copper surface was successfully converted into a superhydrophobic one. This superhydrophobic surface enhanced anti-icing performance by promoting droplet rebound or reducing the icing diameter. A critical formula for predicting droplet rebound under different We and ΔT was provided. Increasing both We and ΔT was unfavorable for droplet to leave the surface. When the droplet rebounded from the surface, the contact time increased slightly with ΔT, but was less significantly affected by We. When the droplet failed to rebound, the icing diameter increased with We and ΔT. However, it remained smaller than that on copper surfaces under the same conditions, which was beneficial for anti-icing. These findings provide valuable insights for the advancement of anti-icing technologies.