70th Annual Meeting of the APS Division of Fluid Dynamics (November 19, 2017 — November 21, 2017)

V0078: Surfaces that force freezing droplets to scrape themselves off

Authors

• Gustav Graeber, Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule Zürich
• Thomas M. Schutzius, Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule Zürich
• Hadi Eghlidi, Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule Zürich
• Dimos Poulikakos, Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule Zürich

DOI: https://doi.org/10.1103/APS.DFD.2017.GFM.V0078

Both in nature and technical applications wetting phenomena and surface icing are important. In this video we present surfaces which force freezing droplets to scrape themselves off. Evaporatively cooled water droplets freeze on engineered surfaces. Heat removal from the droplet free surface results in an inward motion of the freezing front. The volumetric expansion associated with freezing is directed towards the contact area between the droplet and the engineered surface. Here the fluid is not allowed to spread due to the water-repellency of the engineered surface. Further freezing lifts the droplet away from the engineered surface so that it scrapes itself off.