Feasibility Study of a Hybrid Ice Protection System

Abstract

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 electromechanical 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. NomenclatureA = surface area α = mass proportional Rayleigh damping coefficient β = stiffness proportional Rayleigh damping coefficient C3D8E = 8-node three-dimensional linear piezoelectric brick elements C3D8R = 8-node three-dimensional linear brick elements EDM = electro-discharge machining f = frequency FEA = finite element analysis 2 IPS = ice protection system LWC = liquid water content MVD = median volume diameter NACA = National Advisory Committee for Aeronautics p d = power density q = heater density Q m = mechanical quality factor R a = arithmetic mean value of surface roughness SEM = scanning electron microscope T = air temperature  = shear stress V air = velocity of the airstream Subscripts exp = experimental FEA = finite element analysis heater = carbon fiber cord heater int = interface n = natural piezo = piezoelectric st = static condition surf_ice = surface of the ice tot = total condition

Power Management Problem for Civil Aircraft under More Electric Environment

“…Finally, we have known that the electrical load required by the flight control system in period s P 3 ðsÞ is K leak ⋅ ðL e ðsÞ/A e Þ 2 /ρ hy where K leak is the leak coefficient addressing the relationship between the air-dynamical force on elevators and required hydraulic oil mass flow rate [29]. ρ hy is the density of the elevators' hydraulic oil and A e is the area of the elevators (4) The fourth kind of the increased loads for the MEA is the electrical warming of the leading-edge wings and elevators for ice protection [30,31]. The icing, which is usually caused by the supercooled water droplets in clouds where the aircraft is passing by, has been recognized as a potentially dangerous phenomenon for aircraft's flight, since the buildup of ice on the leading edges of wings/elevators can cause an irregular change of the aircraft's maneuverability characteristics and may finally result in the aircraft's loss of control [30].…”

“…Since the above two kinds of costs are only corresponding to the variable x based on (25), the objective function can be stated as the linear expression in (30). The linear constraints in (31), involving only the variable x, contain the constraints which are stated by (3), (13), (14), (26), and (27). The nonlinear constraints in (32), which represent part of the constraints stipulating the stable operation for the engine and ECS while corresponding only to the variables x, include (12) and (28).…”

“…The structure for the PMP formulation stated by (30), (31), (32), (33), (34), (35), (36), and (37) has the following special characteristics: (1) the variables have a clear partition structure which has a merit on using the decomposition method; (2) although the nonlinear expression in (30), (31), (32), (33), (34), (35), (36), and (37) has a nonconvex basics, if we take x as the complicating variables under the GBD architecture, (33) and (34) will separately have a convex form for y and z with given x. Meanwhile, the master problem can be represented by a simplified MINLP formulation and be easily linear-approximately restated by a MILP problem which is finally solved by the mature commercialized software package.…”

Hydrophobic/icephobic coatings based on thermal sprayed metallic layers with subsequent surface functionalization

“…Aiming for applications as icephobic coatings in aircraft, a single hydrophobic coating to prevent or delay ice formation is not likely to be accepted considering strict safety reasons in the aerospace industry. An integration between the electro-thermal de-icing system with the icephobic coatings will have a better chance to be used in aircraft for reduction of energy consumption during electro-thermal heating to remove ice [42,43]. Therefore, an electrothermal heating test rig was applied to evaluate the energy consumption during heating until the ice block detached from the surface of the samples.…”

Feasibility Study of Ultrasonic De-Icing Technique for Aircraft Wing Ice Protection

“…However, the power consumption values are very high for the most common ice protection systems which are thermal. It was reported that consumed power density can reach up to 62 kW/m 2 for electro-resistive anti-/de-icing system [7]. Hot air systems, lead to a loss of power (thrust) from 10 to 15% for a turboprop engine [8].…”