Droplet Impact, Spreading and Freezing on Metallic Surfaces of varying Wettability

Ice formation and accumulation can lead to operational failure and risks for structures, including power transmission lines, aircraft, offshore platforms, marine vessels, and wind turbines. Liquid repellent and icephobic surfaces can reduce ice accretion and improve asset integrity and safety in harsh environments. There are significant needs to probe how wettability affects the droplet impact, ice nucleation and ice accretion processes on different kinds of micro-structured surfaces. This paper presents experimental results of droplet impact, icing delay time and ice accumulation on metallic surfaces with varying wettability. Several different designs of the hydrophobic surfaces are considered. A commercial hydrophobic coating is also used to enhance liquid repellent features and reduce ice accumulation. The results demonstrated that when the static contact angle increases, the total icing time increases, suggesting desirable icing delays. The total icing time decreases with lower surface temperature, higher impact velocity or smaller droplet diameter.