Concentrations of active species in a bulk barrier discharge in a plasmochemical reactor

Abstract

The results of theoretical and experimental studies of the chemical composition of the ensemble of active species formed in a plasmochemical reactor that consists of a multicell bulk-barrier-discharge generator of active species and a working chamber are presented. To calculate the composition of the neutral species in the barrier discharge, an approach based on the averaging of the power input over the entire volume of the discharge gap was proposed. One advantage of this approach is that it involves no adjustable parameters, such as the sizes of the microdischarges, their surface density, and frequency of breakdowns. The calculations and measurements were performed using dry air (with a relative humidity of 20%) as the plasma-forming medium. The concentrations of O3, HNO3, HNO2, N2O5, and NO3 in the discharge gap and working chamber were measured at a mean residence time of the species in the discharge gap of τ = 0.3 s and a specific power input of 1.5 W/cm3. The best agreement between the calculation results and the experimental data was obtained when the temperature of the gas mixture in the discharge was set equal to 400–425 K, a value that coincided with the measured rotational temperature of molecular nitrogen. Generally, the calculated and measured concentrations of O3, HNO3, HNO2, N2O5, and NO3 in both the bulk barrier discharge and the working chamber were found to be in close agreement.