A characterization study on the electrical and fluid-mechanical efficiency of nanosecond-pulsed dielectric barrier discharge plasma actuators

An experimental study is carried out on the efficiency of nanosecond-pulsed dielectric barrier discharge plasma actuators. Investigated parameters are the material and thickness of the barrier as well as the number of nanosecond pulses per burst. The applied experimental technique includes Schlieren, infrared thermography and a back-current shunt for the exact measurement of the voltage signal. The actuator is set upside down in a quiescent environment. Four different dielectric barrier materials are selected and for each material three different thicknesses are tested. The barrier materials chosen are Lexan©, polytetrafluorethylene (PTFE a.k.a. Teflon©), Kapton© and silicone rubber. The experiments are performed in burst discharge mode. Bursts of 30, 40 and 50 pulses at 10. kV and 10. kHz were investigated. The experimental method used to quantify the efficiency of the actuators makes use of thermography measurements captured right after the discharge of the actuator. Experimental data are used as input to estimate the heat flux during the discharge by means of an Inverse Heat Transfer Problem (IHTP). The same experiments are repeated with a Schlieren technique from which the extend in discharge area can be determined. The back-current shunt technique allows for the determination of the electrical efficiency, thus the energy input by the actuator. Results show for most cases an increasing fluid-mechanical efficiency of the plasma actuator by increasing amount of pulses per burst. Moreover, thinner dielectric barriers also show higher efficiencies compared to the thicker ones.