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.
Icing phenomena occur on aircraft and unmanned aerial vehicles (UAVs) under extreme weather conditions. Ultrasonic detection technology is an effective method for measuring ice formation while maintaining the shape of the structure. However, current ultrasonic sensors, which are large and inflexible, are unsuitable for irregular UAV bodies, limiting their applications in real scenarios. For the detection of icing on curved structure, this study proposes a novel flexible ultra-thin ultrasonic transducer (FUTUT). The transducer exhibits excellent flexibility, making it suitable for use on high-curvature wings. Firstly, the FUTUT was designed based on the material properties of the airframe and the sensitivity requirements for ice detection, following the design guidelines for 1-3 type piezocomposites. The fabrication process for the FUTUT was then investigated, and its flexibility and low-temperature resistance were tested. Finally, icing detection experiments were conducted in an icing wind tunnel (IWT), where the FUTUT of 9.82 MHz demonstrated an ice-thickness-detection sensitivity of 0.29 mm. Experimental results indicate that the FUTUT possesses superior flexibility and exhibits excellent stability in low-temperature environments. These results underscore the FUTUT’s promise for applications in ice detection on curved structures.
The flow and heat transfer of the oblique impact of a droplet on a stationary liquid film with various dimensionless thicknesses (01.0–0.5) are investigated experimentally and numerically. A superhydrophobic guideway is used to create the oblique impact of a droplet, which causes subsequent asymmetric crown structure and splashing. The thermal level set method is employed to capture the deformation and heat transfer of warm droplets' oblique impact on a cold liquid film. A parameter study of the effect of Weber number, oblique angle, and liquid film thickness on geometrical characteristics and wall heat flux is carried out. The results show that in the downstream direction, during the crown rising period, the radius is independent of the normal Weber number but increases for a larger tangential Weber number and a thinner liquid film. The maximum downstream crown height increases with an increase in the Weber number and exhibits a non-monotonic trend with the liquid film thickness. The heat transfer rate between the liquid film and surface decreases with larger oblique angles and thicker liquid films while having a poor dependence on the Weber number. In addition, the critical oblique angles for prompting splashing at different liquid film thicknesses are presented. Finally, modified thermodynamics models and splashing thresholds for the liquid film are developed to further enhance the understanding of aircraft icing.