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Alasvand Zarasvand, Kamran

University of British Columbia

Ice accretion is substantially detrimental to a range of different industries worldwide. Current methods for reducing ice adhesion include the use of lubricants, hydrophobic coatings, or soft elastomers, all of which exhibit limited durability. As an alternative, here I suspend sparsely confined metallic sheets and tailor the surface buckling instability, resulting in ice adhesion strengths on par with these prior strategies but without the use of any coatings. These Buckling Elastomer-like Anti-icing Metallic Surfaces, or BEAMS, exhibit low ice adhesion (<1 kPa) and the mechanical durability of metals. The BEAMS sheet confinement, boundary conditions, and physical dimensions of both the ice and the metallic plates can be altered to minimize ice adhesion via the mechanics of plate buckling. I also studied how curvature affects the shear ice adhesion strength of BEAMS, understanding that the compliance of the suspension plays a role in reducing the ice adhesion strength by inducing lateral-torsional buckling. Results from an icing wind tunnel confirmed the efficacy of BEAMS towards impact rime- and glaze- type ice accreted in atmospheric icing conditions. Accordingly, numerical investigation confirmed that the extremely low ice adhesion strength of BEAMS, even on curved surfaces, was due to buckling instabilities either within the thin metal plates or the suspension material. Moreover, the airgap underneath the metal sheet can be substituted with a liquid, altering the ice detachment mechanism and durability of BEAMS. We investigated the effect of the type and viscosity of this liquid on ice adhesion strength and impact resistance of BEAMS. In addition to the excellent passive de-icing performance of BEAMS, we further implemented active de-icing in BEAMS by designing elastomeric suspension points shaped as channels to flow air underneath the suspended sheet. Active de-icing was first achieved by pressurizing the air within the channels to bulge the sheet outward and delaminate accreted ice from the interface. Active de-icing was also performed by flowing room temperature air through the channels to melt the interface. Overall, the active and passive de-icing capabilities of BEAMS make it a promising candidate for improving the operational efficiency of infrastructure in cold environments.

Text; Still Image

2022-10-12

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/82852

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/