Design and Testing of an Efficient and Rapid Electro-Thermal Pulsed Interfacial De-Icing Framework for Electrified Aircraft

Ice and frost accretion on the wings of aircraft can destabilize the air flowpath and cause a drastic increase in stall speed and reduction of lift, putting pilots and passengers at critical risk. While conventional jet-engine aircraft can redirect bleed air from the compressor stage to the leading edges to prevent ice accretion in-flight, electrified aircraft must rely on other means of ice prevention and removal while flying through critical icing regions. The current work outlines the development of an ultra-efficient electrothermal pulsed interfacial de-icing framework which can utilize existing battery power on electrified aircraft for resistive Joule heating for ice and frost removal and mitigation. By supplying a high power pulse to a thin film heater on the leading edges of the wings, the temperature of the interface between the wing and the accreted ice layer can be raised drastically in a short amount of time. This reduces heat diffusion losses of the generated electro-thermal energy through the ice layer and substrate, concentrating the thermal gradient to the interface and allowing rapid de-icing by free-stream shear forces causing shedding of the ice chip. The current design proposes a thin film (400 nm) Indium Tin Oxide (ITO) heating layer on an electrically insulated anodized aluminum substrate. A material survey and selection process considering the ideal voltage and current requirements based on the chosen electrified aircraft's battery voltage and current output limitations guided material selection. Wind tunnel tests under low and high speed freestream velocities of 50 km/h and 100 km/h and sample attack angles of 0 and 45 degrees relative to freestream demonstrate de-icing capabilities for 1-second pulses with power densities < 25 W/cm². Laboratory de-icing tests suggest further reduction in required power densities is likely with the addition of a superhydrophobic layer atop the heating interface. Infrared imaging of patterned heating elements (e.g., parallel bar, serpentine) during pulse testing indicate that localized heating of heater subsections is possible through constricting current pathways in select locations. Increasing local current density may be helpful for introducing localized thermal stresses near the edges of the heater resulting in ice chip cracking and easier removal, as well as potentially reducing power draw requirements from the battery as a result of reduced pulsed surface area at the interface.