Influence of non-uniform electric field distribution on the atmospheric pressure air dielectric barrier discharge

Abstract

The dielectric barrier discharge (DBD) in air at atmospheric pressure is not suitable for industrial applications due to its randomly distributed discharge filaments. In this paper, the influence of the electric field distribution on the uniformity of DBD is theoretically analyzed and experimentally verified. It is found that a certain degree of uneven electric field distributions can control the development of electron avalanches and regulate their transition to streamers in the gap. The discharge phenomena and electrical characteristics prove that an enhanced Townsend discharge can be formed in atmospheric-pressure air with a curved-plate electrode. The spectral analysis further confirms that the gas temperature of the plasma produced by the curved-plate electrode is close to room temperature, which is beneficial for industrial applications. This paper presents the relationship between the electron avalanche transition and the formation of a uniform DBD, which can provide some references for the development and applications of the DBD in the future.

On the chronological understanding of the homogeneous dielectric barrier discharge

“…In 2017, Liu et al [97] proposed a line-plane electrode with floating voltage electrode, which was composed of high-voltage electrode, floating voltage electrode, air gap, barrier medium, and metal electrode. The research on the electric field of the line-plane electrode with floating voltage electrode showed that the strong electric field regions that were conducive to the initial discharge were F I G U R E 1 5 DBD experimental device (a) water electrode air DBD [96]; (b) floating voltage electrode DBD [97]; (c) multilayer DBD [98]; and (d) curved plate electrode DBD [99].…”

“…However, in air, due to the quenching of the nitrogen metastable N 2 (A) by O 2 , Penning ionisation cannot be used for the electron creation to maintain discharge at a low electric field. Consequently, specific electrode structures such as mesh electrodes [68,[87][88][89] and asymmetric electrical structures with small radius components [97,99] were designed to produce seed electrons. Some materials such as electret material [68,[87][88][89][90][91][92][93][94][95][96][97][98][99] and porous alumina ceramic [21,100,101] can also facilitate the seed electron generation in favour of the homogeneous mode.…”

“…Consequently, specific electrode structures such as mesh electrodes [68,[87][88][89] and asymmetric electrical structures with small radius components [97,99] were designed to produce seed electrons. Some materials such as electret material [68,[87][88][89][90][91][92][93][94][95][96][97][98][99] and porous alumina ceramic [21,100,101] can also facilitate the seed electron generation in favour of the homogeneous mode. The mechanism for an electret material to generate a homogeneous discharge can be explained as the desorption current density j des of the electret material (on the order of 10 4 -10 5 cm −2 s −1 , that is only one electron may be emitted from an area of 1 cm 2 during 10 −4 -10 −5 s) is much less than that of an ordinary dielectric barrier material (on the order of 10 10 -10 12 cm −2 s −1 ) after discharge [95,104].…”

“… DBD experimental device (a) water electrode air DBD [96]; (b) floating voltage electrode DBD [97]; (c) multilayer DBD [98]; and (d) curved plate electrode DBD [99]. …”

“…With more than 4 mm gas gap, the discharge stayed in a filamentary mode. In 2021, Cui et al [99] realised the enhanced Townsend discharge in air with a curved plate electrode. Due to low discharge voltage and weak filament discharge intensity, the number of spikes in the current waveform of uneven plate electrode was reduced, and the spikes in the current waveform of curved plate electrode were almost eliminated.…”