Homogeneous dielectric barrier discharge in nitrogen at atmospheric pressure

Abstract

A dielectric barrier discharge in nitrogen at atmospheric pressure was investigated by means of the electrical measurement, the fast photography and the time-resolved spectroscopy. By addition of a nitrogen flow, a stable homogeneous discharge was produced in a gap not longer than 3 mm and it was identified with a Townsend discharge. It was found that the discharge was extinguished while the voltage of the gas gap continued to increase. This extraordinary manner of discharge extinction was explained by the limited number of trapped electrons on the dielectric surface that could not provide a long-lasting Townsend discharge with sufficient secondary electrons. Due to the ‘memory effects’ the lowest breakdown voltage for a Townsend discharge in a 2 mm gap is only 4.9 kV in contrast to the streamer breakdown voltage of 8.2 kV. The working domain of the Townsend discharge is dependent on the frequency and the amplitude of the applied voltage. When the flow velocity increases from 0 to 140 cm s−1, the discharge current decreases from 2.9 to 2.3 mA and the breakdown voltage increases from 5.3 to 5.9 kV, which is attributed to the nitrogen pressure in the gap increasing with the flow velocity. With the gas flow, the intensities of the spectral lines from the second positive system of N2 are almost unchanged, whereas those from NOγ systems are significantly reduced. From this phenomenon, it may be inferred that the density of oxygen as impurity in the discharge gap decreases with the gas flow. This result is in agreement with the existing theory that less oxygen leads to more metastables N2(A) surviving to produce more seed electrons for initiating a Townsend discharge in nitrogen at atmospheric pressure.

Thermoluminescence study of the trapped charge at an alumina surface electrode in different dielectric barrier discharge regimes

“…It is also 46 furthermore known that DBD can run under filamentary or diffuse mode depending on discharge geometry and gas mixture. For instance, the nitrogen discharge can be run in different regime depending on the 48 geometry and other discharge parameters [6,7]. Moreover, the addiction of small quantities of oxygen to a 49 nitrogen discharge transform the regime from glow to filamentary [8].…”

How does the moderate wavy surface affect the discharge behavior in an atmospheric helium dielectric barrier discharge model?

“…According to previous reports, the current intensity of a certain discharge is negatively correlated with its seed electron level because, though more seed electrons can cause the gap breakdown earlier, the discharge will be extinguished before it is fully developed due to the averaged electric field strength over the gap is still weak. However, as can be seen in Figure a1,a2, though the seed electron densities (the electron density at the preionization stage) of w‐DBD with different sizes of d z are indeed higher than that of s‐DBD, the gap voltages presented in Figure b1,b2 show a converse relation.…”

Numerical investigation of Ar–NH3mixture in homogenous DBDs

“…A 0D model for a mixture of Ar/NH 3 dielectric barrier discharge at atmospheric pressure has been investigated. We have tried to compare our discharge current with the discharge current measured experimentally by Bazinette [28]. We noticed that the secondary emission due to the impact of ions and photons are very important to describe the electrical properties of a discharge, these parameters are not taken into account in our model.…”

“…We note here that the model used in the present work is similar to [24,25]. Other interest works on homogenous DBDs at atmospheric pressure were carried out in order to give a better understanding of different physical mechanisms that allowed such homogenous DBDs [23][24][25][26][27][28][29][30]. In particular, the DBD working with Ar-NH 3 mixture at atmospheric pressure provides efficiency in deposit silicon nitride material on silicon solar cells [31][32][33][34].…”