Nanoscale “Earthquake” Effect Induced by Thin Film Surface Acoustic Waves as a New Strategy for Ice Protection

Abstract

Ice accretion often poses serious operational and safety challenges in a wide range of industries, such as aircraft, wind turbines, power transmission cables, oil field exploration and production, as well as marine transport. Great efforts have been expended to research and develop viable solutions for ice prevention. Effective ice protection techniques, however, have yet to be developed. Ice prevention measures that are currently available often consume significant amounts of de‐icing chemicals or energy, and these approaches are expensive to operate and have long‐term economic and environmental impacts. Here, a new ice protective strategy based on thin film surface acoustic waves (SAWs) is proposed that generates: nanoscale “earthquake”‐like vibrations, acoustic streaming, and acousto‐heating effects, directly at the ice–structure interface, which actively and effectively delays ice nucleation and weakens ice adhesion on the structure surface. Compared with the conventional electro‐thermal de‐icing method, the SAW approach demonstrates much‐improved energy efficiency for ice‐removal. The potential for the dual capability of autonomous ice monitoring and removing functions using the SAW generation elements as transducers is also explored.

Dynamic Mitigation Mechanisms of Rime Icing with Propagating Surface Acoustic Waves

“…For the newly attached supercooled droplets that are generated in the subzero environment, the SAWs prevent ice nucleation and accretion by restricting the size of ice embryos to be smaller than the critical nucleolus radius, r c , and increasing the critical free energy of heterogeneous ice nucleation, Δ G *, which has been reported in ref ( 31 ). The attached supercooled droplets are also affected by vibration and thermal effects.…”

“… 60 , 61 As it is well known, the conventionally used electrothermal de-icing technique generally has low energy efficiency and high energy consumption, 12 , 62 whereas the SAW technology has its advantages such as the high efficiency for the de-icing process because of the combined effects of acoustic vibration and acoustic thermal effects, both of which are localized at the ice/device interface, as reported in Yang et al . 31 …”

“…Nanoscale surface wave vibrations (induced by the propagating SAWs from the surface into ice or liquid) and the acoustic thermal heating effect are two main mechanisms for ice protection using SAW devices. 31 They play key roles in the anti/de-icing process by preventing ice accumulation and effectively removing the formed ice. 31 In this section, we address this issue by considering the phase evolution of ice, water, and vapor and connect them with anti/de-icing mechanisms with SAWs.…”

“… 31 They play key roles in the anti/de-icing process by preventing ice accumulation and effectively removing the formed ice. 31 In this section, we address this issue by considering the phase evolution of ice, water, and vapor and connect them with anti/de-icing mechanisms with SAWs. The hypotheses about the anti/de-icing processes and mechanisms are first established and then proved by the designed experiments.…”

Reduction of Ice Adhesion Using Surface Acoustic Waves: Nanoscale Vibration and Interface Heating Effects

“…New methods for anti/deicing functions which can be achieved economically and safely are still critically needed. 21 This paper presents a fundamental strategy for reducing the ice adhesion and provides first insight in deicing mechanisms using the surface acoustic waves (SAWs) 22,23 (as illustrated in Figure 1). SAW generates high-frequency surface vibrations exhibiting nanoscale "earthquakes" 24 during its propagation on the structural surface, which causes surface vibration and is able to concentrate propagating wave energy into a depth of one or two wavelengths on the SAW device surface.…”