Study On The Discharge Characteristics Of Corona-dielectric Barrier Discharge

Corona discharge and dielectric barrier discharge are the techniques that produce non-thermal plasma at atmospheric pressure. The high-energy activated species that needed in chemic reaction are generated by dielectric barrier discharge, and the electron density is high, but the high onset voltage and the small discharge space are disadvantages. The discharge space of corona discharge is large and the onset voltage is low, but discharge power and electron density are low. The corona-dielectric barrier discharge can depress onset voltage, improve electron density and augment discharge space.The needle-to-plate corona-dielectric barrier discharge are designed in this paper, the discharge characteristics are investigated by measurements of voltage-current waveforms and discharge photograph. Compared the discharge between with ceramic fiber as packing dielectric and without ceramic fiber, it shows that: when without ceramic fiber,during the positive voltage, discharge represents streamer discharge; During the negative voltage, discharge represents Trichel pulses or corona glow. It can be explained by transference of space charge that showed in the ICCD pictures. When with ceramic fiber as packing dielectric,there are obvious discharge pulses during the positive and negative voltage, the discharge pulse number and current amplitude during positive voltage are much more than negative voltage. The later has less onset voltage of discharge than the former.The discharge power of single needle-to-plate and multi needle-to-plate are calculated. Result shows that: under the same discharge voltage, the discharge power of packing with ceramic fiber is greater than that without ceramic fiber; it decreases with the increasing of gas gap distance, but the unit space discharge power increases. The discharge power increases with gas flow,but the influence of gas flow is faint. Because of inhibition among needles, at the same onset voltage and same discharge gap, the discharge power of single needle is higher than the per needle discharge power of multi-needle.At the same conditions, compared with traditional DBD, the discharge voltage of Corona induced DBD is lower and the amount of charge transmission is larger. The discharge streamer development of Corona induced DBD is that the streamers come from positive cathode then some stop at the corona induced wire, the others arrive at negative cathode.