New Approach to Dielectric Barrier Discharge Plasma Actuator Materials for Active Flow Control Applications
Dielectric Barrier Discharge (DBD) plasma actuators are simple devices with great potential for active flow control applications due to their low cost, low weight, compatibility with aerodynamic surfaces, absence of moving parts, real-time control and fast response ability. A DBD plasma actuator is typically composed by two asymmetric electrodes (exposed and embedded) separated by a dielectric layer, which plays an essential role in the actuating performance. The most used material to produce the dielectric layer of DBD actuators is the commercial polyimide Kapton, due to its outstanding features for this application, such as dielectric strength, large withstanding temperature range, chemical and radiation resistance, among others. However, the pursue of even better performances has driven the scientific community for novel alternatives to this material and to explore the possibility of producing multifunctional dielectrics. In this sense, novel commercial polyimides such as Cirlex (high temperature resistance, dimensional stability, chemical resistance), fluorinated polymers PVDF � polyvinylidene fluoride (low density, remarkable electroactive properties) and Teflon � polytetrafluoroethylene (dielectric strength, flexibility, high strength), or reinforced thermosets (excellent mechanical properties, dimensional stability up to high temperature, easy to functionalize) are being evaluated for DBD plasma actuator applications. These materials were used to produce DBD plasma actuators and their performance in terms of power consumption, induced flow velocity, mechanical efficiency and thermal behavior was studied. Since some of them can be used as structural materials, the actuators can thus be an integral part of the structure instead of being attached to the surface, thus giving multifunctional character to the structure. Further, some of the aforementioned materials also present electroactive properties (piezo- and pyroelectricity), being therefore also suitable as self-sensing materials. These approach enables the fabrication of structures with self-flow control capabilities, without the integration of external devices that can affect the aerodynamics, and pave the way for the sensing of the structures taking advantage of the electroactive nature of the materials.