Investigation on the reaction mechanisms of generation and loss of oxygen-related species in atmospheric-pressure pulsed dielectric barrier discharge in argon/oxygen mixture

This work presents a numerical investigation, using a 1-D fluid model, on the generation and loss of oxygen-related species and the spatial-temporal evolutions of the species densities in the atmospheric-pressure pulsed dielectric barrier discharge in the argon/oxygen mixture. The reaction pathways as well as their contributions to the generation and loss of oxygen-related species are given. The considered oxygen-related species include O, O(1D), O2(1Δg), O3, O+, O2 +, O−, O2 −, and O3 −. The following significant results are obtained. O, O(1D), O2(1Δg), and O− are produced mainly via the electron impact with O2. Ar+ plays an essential role in the generation of O+ and O2 +. Almost all of O3 derives from the reaction O2 + O2 + O → O3 + O2. The O3-related reactions produce an essential proportion of O2 − and O3 −. The substantial loss of O−, O2 −, and O3 − is induced by their reactions with O2 +. Loss of O+, O, and O(1D) is mainly due to their reactions with O2, loss of O2(1Δg) due to O2(1Δg) impacts with O3 as well as the de-excitation reactions between O2(1Δg) and e, O2, and O, and loss of O3 due to the reactions between O3 and other neutral species. In addition, the densities of O+ and O(1D) present two obvious peaks at the pulse duration, but the densities of O2 +, O, O2(1Δg), and O3 are almost unchanged. The densities of negative oxygen ions increase at the pulse duration and then decline. O− density is obviously large nearby the dielectric surfaces and the densities of O2 − and O3 − present generally uniform distributions.