Theoretical study of column of discharge with liquid non-metallic (tap water) electrodes in air at atmospheric pressure

Abstract

The discharge established between two liquid non-metallic electrodes (DLNME) is investigated. This d.c. discharge burns between two streams of tap water in open air at atmospheric pressure in diffuse form. In the plasma column two zones are defined: one close to the near-cathode and the other one close to the near-anode regions of the discharge. In each zone, the composition, massic enthalpy, volumetric emissivity of N2(2+) spectral band (376-380 nm), hydrogen spectral line (Hα) and triplet oxygen spectral lines (777 nm) have been calculated in non-equilibrium conditions. The comparison with experimental results allows determining the ratio between translational temperature of electrons and that of heavy species and an upper limit of the air humidity in both zones. This type of calculation describes satisfactorily the previously obtained experimental results.

Measurement of OH radicals at stateX2Π in an atmospheric-pressure micro-flow dc plasma with liquid electrodes in He, Ar and N2by means of laser-induced fluorescence spectroscopy

“…The measured H 2 O content is in agreement with the result for the glow discharge above water obtained by the Rayleigh scattering technique [24] where the highest limit of H 2 O density for a short gap of 3 mm, in contrast to 7 mm in the present work, is estimated as 30% (current 50 mA). Andre et al [25] estimated the upper limit of water content in the anode and cathode zones of the glow discharge in between two water layers as 25% and 45%, respectively. Smaller H 2 O density of 10% measured in the present work can be explained by the fact that measurements were done in the positive column in contrast to the work of Andre et al [25] and also a gas flow was used which can decrease the H 2 O density in the discharge.…”

“…Andre et al [25] estimated the upper limit of water content in the anode and cathode zones of the glow discharge in between two water layers as 25% and 45%, respectively. Smaller H 2 O density of 10% measured in the present work can be explained by the fact that measurements were done in the positive column in contrast to the work of Andre et al [25] and also a gas flow was used which can decrease the H 2 O density in the discharge. Based on the above-presented data, the groundstate OH density in the positive column of the discharge can be calculated when calibration of the detection system, e.g.…”

Validation of gas temperature measurements by OES in an atmospheric air glow discharge with water electrode using Rayleigh scattering

“…When the water concentration increases to 10% or more the effective radiative lifetime reduces so much that almost all emission occurs during the first few nanoseconds and thermalization is no longer possible. These concentrations are realistic for plasmas in contact with liquids [9,18,19].…”

A simple generator of a stationary flow of non-equilibrium atmospheric-pressure plasma

“…The opinion that the rotation temperature obtained from N 2 2+ system emission is a good estimation of the gas temperature is confirmed by the results of number investigations (see, for example, [9] and the references therein). Also, this part of the spectrum can be used for the estimation of the degree of the non-equilibrium, because the temperature of excitation of N 2 (C) is close to the electrons temperature [5].…”

“…The first publications on investigations of such discharges appeared in the early 1980s (see [3] and the references in it). Later it was proven that this discharge really generated plasma out of thermal equilibrium [4,5]. In the paper the simple source of non-thermal atmospheric pressure plasma on the basis of the DLNME with tap-water cathode and ring metallic anode is presented.…”