Reducing Static and Impact Ice Adhesion with a Self-Lubricating Icephobic Coating (SLIC)

Edem Tetteh,Eric Loth

doi:10.3390/coatings10030262

Abstract

Ice accumulation and adhesion can problematically occur on many engineering systems, such as electrical power networks, wind turbines, communication towers, and aircraft. An optional solution to these icing problems is the use of surfaces/coatings with low ice adhesion properties: Icephobic surfaces. Icephobic surfaces/coatings are very beneficial, as they facilitate the removal of ice or retard its formation and do not require the use of any sort of energy. A compact icing research tunnel (CIRT) was employed to measure ice tensile adhesion strength for both impact and static ice on a conventional metal surface (aluminum) and on a Self-Lubricating Icephobic Coating (SLIC) surface. The static ice consisted of deionized water slowly poured over the surface and left to be frozen on the test specimen surface at stationary conditions, while impact ice consisted of droplets of mean volumetric diameter (MVD) of 13 μm impacting the test specimen surface at a velocity of 40 m/s and freezing and accreting dynamically. The results revealed that static ice has an ice tensile adhesion stress higher than that of impact ice for the conditions used, consistent with previous studies. Additionally, a reduction of more than half was observed in ice tensile adhesion stress for SLIC compared to aluminum for both impact and static ice, and this performance stayed consistent even after multiple icing tests on the same sample. The SLIC coating hydrophobicity (roll-off angle and contact angle) also demonstrated resilience to icing and mechanical abrasion, confirming the self-healing properties.

Highlights

Atmospheric ice accretion is a great concern for several engineering applications
The static ice consisted of deionized water contained in a cylindrical mold left to freeze over time on the tested surfaces at a temperature of −20 ◦ C
The results showed that generally, impact ice has a tensile adhesion strength lower than that of static ice

Summary

Introduction

Atmospheric ice accretion is a great concern for several engineering applications. For engines, ice accretion on various components (as shown in Figure 1a) was reported to result in problems such as engine rollback, compressor stall/surge, and flameout. Other applications that suffer heavily from icing are wind turbines. Ice accumulation on wind turbine blades, as shown, modifies their aerodynamic characteristics, resulting in a decrease of power production [2,4,5]. Up to a 17% loss in Annual Energy Production (AEP) and a power coefficient reduction into the range of 20–50% were reported for wind turbines due to icing [4]. Ice accretion on these blades and irregular shedding typically result in load imbalances and, subsequently, in an excessive turbine vibration [6]

Objectives

Results

Conclusion