Experimental Research of OH and N 2 + Spatially Resolved Spectra in a Needle-Plate Pulsed Streamer Discharge

Abstract

In this study, the spatial distributions of the emission intensity of OH (A 2 R!X 2 P; 0-0) and N þ 2 ðB 2 R þ u ! X 2 R þ g ; 0-0, 391.4 nm) are investigated in the atmospheric pressure pulsed streamer discharge of H 2 O and N 2 mixture in a needle-plate reactor configuration. The effects of pulsed peak voltage, pulsed repetition rate, input power, and O 2 flow rate on the spatial distributions of the emission intensity of OH (, and the vibrational temperature of N 2 (C) in the lengthwise direction from needle to plate are attained. It is found that the emission intensities of OH (A 2 R!X 2 P; 0-0) and N þ 2 ðB 2 R þ u ! X 2 R þ g ; 0-0, 391.4 nm) rise with increasing the pulsed peak voltage, the pulsed repetition rate and the input power, and decrease with increasing O 2 flow rate. In the direction from needle to plate, the emission intensity of OH (A 2 R!X 2 P; 0-0) decreases firstly, and rises near the plate electrode, while the emission intensity of N þ 2 ðB 2 R þ u ! X 2 R þ g ; 0-0, 391.4 nm) is nearly constant along the needle to plate direction firstly, and rises sharply near the plate electrode. The vibrational temperature of N 2 (C) is almost independent of the pulsed peak voltage and the pulsed repetition rate, but rises with increasing the O 2 flow rate and keeps nearly constant in the lengthwise direction. The main physicochemical processes involved are discussed.

The investigation of OH radicals produced in a DC glow discharge by laser-induced fluorescence spectrometry

“…Many researchers have devoted much effort to measuring the optical emission spectra (OES), laser-induced fluorescence (LIF) spectra, density and lifetime of OH radicals to enhance the number of OH radicals in different kinds of discharges and various electrical structures [19][20][21][22]. Liu et al measured the OES intensity and spatial distribution of OH radicals in a N 2 +H 2 O mixture gas needle-plate and wire-plate pulsed corona streamer discharge and optimized the emission intensity of OH radicals by adjusting the voltage, frequency and O 2 addition [10,[23][24][25]. The production and depletion of OH, O, and H were also calculated from the recorded emission intensities, reaction processes and corresponding reaction rates [26].…”