Characteristics of Coaxial Dielectric Barrier Discharge at Atmospheric Pressure

Abstract

To further explore the conditions and mechanisms of generating uniform plasma in the flowing gas at atmospheric pressure, the dielectric barrier discharge (DBD) characteristics of the flowing helium, helium/oxygen mixture and the helium/methane mixture were studied at atmospheric pressure in this paper. A coaxial cylindrical double air gap structure was researched by discharge experiment at atmospheric pressure, using a high frequency and high voltage AC power source at a flow rate of 4 L/min. The discharge current is recorded by camera, the waveforms of current and voltage are recorded by oscilloscope. The discharge patterns and evolution processes of different gases in this structure were analyzed. The experimental results show that the helium can achieve uniform discharge in the structure with the frequency of 12kHz and the voltage of 1-2kV. The discharge pattern is glow discharge. Discharge forms of Helium/methane mixture and helium/oxygen mixture were filament discharge. The current waveform has obvious asymmetry in the positive and negative half cycles. The discharge mainly occurs in the positive half cycle, and the asymmetry gradually decreases with the increase of the voltage.