Surface-charge control strategy for enhanced electrohydrodynamic force in dielectric barrier discharge plasma actuators
Shintaro Sato, Kodai Mitsuhashi, Tomoki Enokido, Atsushi Komuro, Akira Ando, Naofumi Ohnishi
Abstract
Abstract A relationship between electric potential distribution on a dielectric surface and electrohydrodynamic (EHD) force generation is experimentally investigated to improve the performance of dielectric-barrier-discharge (DBD) plasma actuators. Direct current (DC) biased repetitive pulses are applied to the DBD plasma actuator, which has two or three electrodes. Although the additional downstream exposed electrode has little effect on the electrical and optical characteristics of the DBD plasma actuator, the electric potential distribution strongly depends on the presence of the additional exposed electrode. Moreover, the saturation time of the surface charge is hundreds of milliseconds when the pulse repetition frequency is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>5</mml:mn> <mml:mtext> </mml:mtext> <mml:mrow> <mml:mi mathvariant="normal">k</mml:mi> <mml:mi mathvariant="normal">H</mml:mi> <mml:mi mathvariant="normal">z</mml:mi> </mml:mrow> </mml:math> , showing a large difference in the time scale of surface DBD. We also demonstrated a significant improvement in the generation of ionic wind by adding an additional downstream exposed electrode owing to the prevention of the electric field screening. A concept that separates the ionization process and the acceleration process works properly for improving the performance of the DBD plasma actuators, but at the same time, the dynamics of the surface charge should be controlled so that a strong electric field is generated rather than the electric field being screened by surface charge.