Homogeneous dielectric barrier discharges in atmospheric air and its influencing factor

Abstract

The stable homogeneous dielectric barrier discharge (DBD) is obtained in atmospheric 2–3 mm air gap. It is generated using center frequency 1 kHz high voltage power supply between two plane parallel electrodes with specific alumina ceramic plates as the dielectric barriers. The discharge characteristics are studied by a measurement of its electrical discharge parameters and observation of its light emission phenomena. The results show that a large single current pulse of about 200 μs duration appearing in each voltage pulse, and its light emission is radially homogeneous and covers the entire surface of the two electrodes. The homogeneous discharge generated is a Townsend discharge during discharge. The influences of applied barrier, its thickness, and surface roughness on the transition of discharge modes are studied. The results show that it is difficult to produce a homogeneous discharge using smooth plates or alumina plate surface roughness Ra < 100 nm even at a 1 mm air gap. If the alumina plate is too thin, the discharge also transits to filamentary discharge. If it is too thick, the discharge is too weak to observe. With the increase of air gap distance and applied voltage, the discharge can also transit from a homogeneous mode to a filamentary mode. In order to generate stable and homogeneous DBD at a larger air gap, proper dielectric material, dielectric thickness, and dielectric surface roughness should be used, and proper applied voltage amplitude and frequency should also be used.

On the chronological understanding of the homogeneous dielectric barrier discharge

“…The "shallow trap" effect on the surface of alumina ceramics provides additional seed electrons and forms a uniform discharge in the air. Ran et al [21,101] studied the influence of dielectric surface morphology on discharge mode using different dielectric materials with similar equivalent capacitance and barrier media with surface morphology as shown in Figure 16. The results showed that the surface morphology of the dielectric materials played an important role in the discharge mode.…”

“…Non-equilibrium atmospheric pressure plasma (N-APP) is a promising technology for generating high concentration reactive species at a relatively low gas temperature or room temperature [1-8], making it highly attractive for a variety of applications such as surface modification, decontamination of temperature-sensitive materials, and more [9][10][11][12][13][14][15]. Among the different methods used for generating N-APP, dielectric barrier discharge (DBD) is one of the most widely studied techniques and has been explored for more than a century [16][17][18][19][20][21][22]. In DBD, one or two dielectrics are inserted into the discharge circuit, which requires ignition of the discharge using alternating-current (AC) voltage or pulsed direct-current (DC) voltage.…”

“…In short, DBD has been under investigation for decades; however, numerous unanswered questions remain. One particular example pertains to the proposed theory on N 2 homogeneous DBD, which suggests that generating a homogeneous DBD in the air is a difficult task [54][55][56][57][58][59][60]. This is due to the high concentration of O 2 , which swiftly extinguishes the metastable state of N 2 , within a timeframe much shorter than the period between consecutive discharges.…”

Influence of N 2 pressure on surface discharge characteristics of PEEK under positive repetitive square voltage

“…In terms of IGBT device package insulation, Mark Sweet found that both N 2 pressure and gas type have a significant impact on the insulation strength through electric field simulation [22]. All in all, research into the influence of gas pressure on partial discharge mainly focuses on DC, AC voltage [5,6] and nanosecond pulse sequence [17,18,23]. The influence of N 2 pressure on the surface discharge under positive repetitive square voltage has rarely been investigated.…”

“…Besides, it was found by spectrum analysis that the proportion of the corresponding high-frequency components of the discharge current increases with the increase in gas pressure [6]. Research has indicated that the characteristics of dielectric barrier discharge (DBD) under nanosecond pulse sequence are affected by gas pressure [17,18].…”