Abstract
Dielectric Barrier Discharge (DBD) plasma actuators are simple devices with great potential for active flow control applications. Further, it has been recently proven their ability for applications in the area of heat transfer, such as film cooling of turbine blades or ice removal. The dielectric material used in the fabrication of these devices is essential in determining the device performance. However, the variety of dielectric materials studied in the literature is very limited and the majority of the authors only use Kapton, Teflon, Macor ceramic or poly(methyl methacrylate) (PMMA). Furthermore, several authors reported difficulties in the durability of the dielectric layer when the actuators operate at high voltage and frequency. Also, it has been reported that, after long operation time, the dielectric layer suffers degradation due to its exposure to plasma discharge, degradation that may lead to the failure of the device. Considering the need of durable and robust actuators, as well as the need of higher flow control efficiencies, it is highly important to develop new dielectric materials which may be used for plasma actuator fabrication. In this context, the present study reports on the experimental testing of dielectric materials which can be used for DBD plasma actuators fabrication. Plasma actuators fabricated of poly(vinylidene fluoride) (PVDF) and polystyrene (PS) have been fabricated and evaluated. Although these dielectric materials are not commonly used as dielectric layer of plasma actuators, their interesting electrical and dielectric properties and the possibility of being used as sensors, indicate their suitability as potential alternatives to the standard used materials. The plasma actuators produced with these nonstandard dielectric materials were analyzed in terms of electrical characteristics, generated flow velocity and mechanical efficiency, and the obtained results were compared with a standard actuator made of Kapton. An innovative calorimetric method was implemented in order to estimate the thermal power transferred by these devices to an adjacent flow. These results allowed to discuss the ability of these new dielectric materials not only for flow control applications but also for heat transfer applications.
Active Flow Control of Wind Turbine Blades
