Feasibility study of a hybrid ice protection system

A key design factor impacting the utilization of electrical power to drive aircraft systems and subsystems is energy efficiency. With the design of an all-electric, hybrid ice protection system, energy consumption can be reduced to a large extent. The hybridization is achieved through an intentional partitioning of the ice at the stagnation line by melting via surface heating and ice shedding in the unheated regions of the airfoil surface via an electro-mechanical deicing system based on piezoelectric multilayer actuators. In addition, to reduce energy consumption, the adhesion forces between the ice and the airfoil surface can be reduced using an ultrasmooth, nanostructured surface with water and ice repellent properties that encourages ice shedding. Experimental investigations, performed in a laboratory-scale icing wind tunnel for a small-scale system configuration, reveal that the hybrid approach for ice protection reliably sheds the ice accreted on the airfoil surface. Compared to conventional state-of-the-art systems for ice protection, the hybrid approach is able to reduce power consumption up to 95%. Beyond the laboratory tests, numerical simulations of the hybrid strategy analogous to the one used for the experiments are performed. The time history of the residual ice shapes aft of the heated region are simulated using the ice accretion prediction software LEWICE2D for a wet-running anti-icing subsystem. Finite element analyses of the effects of the piezoelectric actuators are then performed using Abaqus to investigate the ice shedding capability in the unheated regions of airfoil surface. It is shown that the variation in the thickness of the different ice shapes affects the stiffness of the model, and the ice shedding capability, respectively. Simulation results correlate well with experimental results obtained with the icing wind tunnel. It can be concluded that reliable operation of the hybrid system for ice shedding can be guaranteed when using a harmonic sweep excitation able to excite the structure at its resonance.