Fabricating and developing superhydrophobic anti-icing surfaces have been a research hotspot for eliminating undesired icing issues. Among various fabricating strategies, ultrafast laser micro-nano fabrication is regarded as a greatly promising technique owing to its advantages of high geometric accuracy, highly flexible microstructure or dimension availability, no contact, and no material limitation. A number of diverse micro-nanostructured superhydrophobic surfaces have been developed by ultrafast lasers and demonstrated extraordinary anti-icing properties. They are collectively known as ultrafast laser-fabricated superhydrophobic anti-icing surfaces (ULSASs). In this article, we reviewed the recent advances in ULSASs from micro-nano structure fabricating to anti-icing performances and to potential applications. The surface wettability and mechanisms of ultrafast laser micro-nano fabrication are first introduced, showing the strong ability of ultrafast laser for fabricating superhydrophobic surfaces. Then the deepened understanding of the relationship between superhydrophobicity and icephobicity is discussed in detail, including Cassie–Baxter stability, surface durability and environmental adaptability. Eventually, the passive anti-icing technique, the passive/active combined anti-icing technique and their practical applications are presented together with current challenges and future prospects.

When an aircraft passes through clouds containing supercooled water droplets, the leading edge’s surface will gradually accumulate ice. Ice surface roughness is an important parameter affecting the local convective heat transfer coefficient and the water collection coefficient, which in turn affect the ice’s shape. However, because the surface roughness of aircraft icing is a transient value varying in time and space, it is extremely difficult to measure with existing methods in real time. In this study, a noncontact ultrasonic pulse-echo (UPE) technique is applied to characterize the ice roughness of an airfoil model’s surface. A multilayer model with equivalent bead-like roughness profiles is established to study the effects of changes in ice roughness on ultrasonic echo signals. A series of simulations indicated that ice roughness can be measured quantitatively and effectively in the range of [11.6, 120] μm. Based on these simulations, an experimental UPE device was developed to measure echo signals on top of the ice corresponding to surface roughness. The results show that for both the regular and irregular surface roughness samples, the maximum relative error in the roughness is less than 15%. Meanwhile, we designed and supplemented the experiment with the NACA-0012 airfoil model to realize the online measurement of ice roughness in an icing research tunnel.

The hybrid Ice Protection System combining thermoelectric and superhydrophobic coating is efficient and benefits from low-energy consumption. In order to explore the application details of superhydrophobic coating, this paper investigated the sensitivities of the Ice Protection System parameters including the range of the superhydrophobic coating, heating range and power to icing environmental parameters. In this paper, an icing wind tunnel test was adopted to study the performance of this Ice Protection System under different icing conditions, as well as the influence of the superhydrophobic coating range, heating range and power variation on ice protection. The results showed that the superhydrophobic coating is effective only when it covers the droplet impingement area, with the heating power requirement emerging as a critical design consideration that is extremely sensitive to environmental temperature changes. Additionally, median volumetric diameter determines the protection area to be protected, while liquid water content variation has little effect on the designed Ice Protection System in contrast.

A series of experimental studies were conducted to explore the fluctuation characteristics of the water film under the air flow condition with the research background of the anti-icing system. The dynamic measurement of the water film on the surface of the aluminum-based plate was achieved using the digital image projection measurement technology. The influence of diverse wind speeds and Reynolds numbers on the average water film thickness, fluctuation intensity, and velocity of the liquid film was analyzed. The piecewise characteristics of the wind speed and Reynolds number for the fluctuation characteristics of the water film were analyzed innovatively. The fluctuation characteristics and formation principle of each stage were also examined. The results had a significant impact on establishing and modifying the mesoscopic models of aircraft icing to improve the design methodology of the anti-icing process.

Supercooled droplets that collide with the windward surface of the aircraft will freeze, which results in icing on both stationary and rotating components. The ice accretion on rotating surfaces is physically different from those on stationary components. The icing phenomenon on the surface of a rotating intake cone was investigated in an icing wind tunnel, and the influence of icing conditions of supercooled large droplets on the experimental results was analyzed. In the experiments, the ice accretion of the intake cone was studied under various conditions, including rotational speed, wind speed, icing temperature, droplet diameter, and icing time. The ice shape on the surface of the intake cone is notably unique due to the influence of centrifugal force, which produces a longer feather-like ice structure that has a significant effect on the performance of the engine. The process of ice shedding caused by centrifugal force is also critical for the engine anti-icing process. Therefore, it is essential to study the icing characteristics under rotational effects during the design and verification process of engine anti-icing systems.