Development of a hybrid ice protection system based on nanostructured hydrophobic surfaces

Eliminating the hazard of aircraft icing still remains a challenge. Thermal-based ice protection systems are widely used to remove in-flight ice accretions. For reasons of power consumption, coatings that reduce the adhesion of the ice represent suitable approaches to protect aircraft surfaces susceptible to ice accretion. This effort intends to tailor an ultrasmooth surface with hydrophobic and icephobic properties, respectively, which are obtained by nanostructuring and subsequent surface hydrophobizing. A hybrid method of ice protection is presented in this study, where the ultrasmooth hydrophobic surface is applied on the surface of a small-scale NACA 0012 airfoil. The hybrid system further consists of a thermo-electric heater element for ice partitioning at the stagnation line by melting. Ice shedding in the unheated portion of the airfoil surface is performed by piezoelectric multilayer actuators. System performance is studied in a laboratory icing wind tunnel where it becomes evident that using the ultrasmooth, nanostructured hydrophobic surface encourages ice shedding from the airfoil surface. Measurement results also reveal that the hybrid system reduces the amount of power consumption by up to 95 % compared to state-of-the-art ice protection systems.