A novel electro-thermal anti-icing system for fiber-reinforced polymer composite airfoils

For the first time, the concept of embedded thermal elements as an anti-icing system for polymer composite airfoils used in wind turbine blades and aircraft wing structures is proposed, and developed experimentally and numerically. A manufacturing technique was developed to implement the electro-thermal anti-icing system in the form of discrete constantan thermal elements with a specific pattern inside the composite airfoil. Thermography was used to understand the surface temperature distribution of the composite airfoil surface in cold (dry) and icing (wet) condition tests. Two composite airfoil samples with two different thermal elements' patterns were made to study the effect of wires' spacing on the airfoils' surface temperature distribution, and the effectiveness of the thermal elements' pattern for icing mitigation. Thermal elements of the anti-icing systems were energized by using two different power schemes to determine and adjust the required power to have an ice free composite airfoil, and adjust the amount of power consumption. A numerical thermal analysis was performed to determine the power threshold in the anti-icing system to prevent thermal degradation of the polymer composite. Thermal modeling was also used to explain some of the experimental observations. Experimental data and thermal analysis are in a good agreement, indicating the feasibility of using thermal elements as anti-icing system for surface heating in order to prevent ice accretion on polymer composite airfoils.