Realization of homogeneous dielectric barrier discharge in atmospheric pressure argon and the effect of beads on its characteristics

Abstract

This paper describes the realization of homogeneous dielectric barrier discharge (DBD) in argon at atmospheric pressure. The effect of the morphology of the dielectric surface (especially the dielectric surface covered by hollow ceramic beads (99% Al2O3) with different diameters) on discharge is investigated. With different dielectrics, the argon DBD presents two discharge modes, namely, a filamentary mode and a homogeneous one. Fast photography shows that the filamentary mode operates in a streamer discharge, and the homogeneous mode operates in a Townsend discharge regime. It is found that a homogeneous discharge can be generated within a certain voltage range. The range of voltage amplitude decreases, and the breakdown voltage increases with the increase of the mean diameter of the ceramic beads. Waveforms of the total current and optical emission signal present stochastic pulses per half voltage cycle for the filamentary mode, whereas one single hump per half voltage cycle for the homogeneous mode. In the homogeneous mode, the intensity of optical emission decreases with the mean diameter of the ceramic beads. The optical emission spectrum is mainly composed of atomic lines of argon and the second positive system of molecular nitrogen. It reveals that the electron density decreases with increasing mean diameter of the ceramic beads. The vibrational temperature increases with increasing mean diameter of the ceramic beads. It is believed that a large number of microdischarges are formed and smaller ceramic beads have a larger activation surface area and more point discharge. Electrons liberated in the shallow well and electrons generated from microdischarges can increase the secondary electron emission coefficient of the cathode and provide initial electrons for discharge continuously. Therefore, the breakdown electric field is reduced, which contributes to easier generation of homogeneous discharge. It is confirmed by the simulation results.

Research on new ceramic debinding technology with low energy consumption via dielectric barrier discharge

“…In addition, the method can be improved in the following aspects. Firstly, by customizing the electrode shape [25] and utilizing various dielectric barrier materials [26], the uniformity of the electric field can be increased. Secondly, we can make the sample bigger and create a multi-layer reactor to process several samples simultaneously [27].…”

Full cycle, self-consistent, two-dimensional analysis of a packed bed DBD reactor for plasma-assisted CO2 splitting: spatiotemporal inhomogeneous, glow to streamer to surface discharge transitions

“…It is known that the operation of DBDs in various gases present both homogeneous (glow or Townsend or diffuse) and filamentary (streamer or MD regimes) modes. Homogeneous DBDs have been realized and studied in several studies [61] including operation in pure atmospheric pressure CO 2 [62]. The transition to the filamentary mode (streamer/MD regimes) is surely more complex and typically relates to small inhomogeneities of the reactor, surface imperfections, etc which lead to the initiation of multiple filamentary discharges along the z-(axial) direction.…”