Characterization of surface dielectric barrier discharge (SDBD) based on PI/Al₂O₃ nanocomposite

Surface dielectric barrier discharge (SDBD) is widely applied in the field of active flow control. Its carrier is usually called plasma actuator (PA). However, it has a key drawback of short discharge lifetime due to the dielectric degradation under plasma processing. In this paper, polyimide (PI) film incorporated with Al₂O₃ nanoparticles is fabricated and used as dielectric of PA. Dielectric material, plasma, surface temperature, discharge characteristics as well as its performance are experimentally studied and compared with those of a conventional pure PI based control actuator. The results show that at sine peak to peak voltage of 8 kV and 6 kHz frequency, the force efficiency of new designed actuator is 2.5 times higher than that of the control actuator after 30 h discharge. Besides, the discharge lifetime is also 3.2 times as long. In the discharge region, the surface of the control actuator appears serious dielectric degradation, which is accompanied by heat accumulation as well as an increase of gas temperature and electron temperature. While for the new actuator, after selective plasma etching, the inorganic Al₂O₃ nanoparticles can continuously resist the discharge plasma and contributes to effective heat dissipation and more stable plasma parameters.