Global model simulation of OH production in pulsed-DC atmospheric pressure helium-air plasma jets

Abstract

The results of global model simulation of an atmospheric pressure pulsed-DC helium plasma jet propagated in humid air, compared to the results of fluid model, are presented in this paper. The primary tasks of presented simulation were determination of the density and the main production pathways of OH radicals. The calculation reveals that global model gives higher OH densities than fluid model, especially at higher electron temperatures. This overestimation is mainly caused by the intrinsic assumptions of the global model, which impose limitations on its application for modelling of very transient physical processes such are streamers or plasma bullets. The main OH production and loss processes are well recognized by global model, and additional mechanisms are involved with respect to the case of fluid modelling. According to the presented results, global model will give satisfactory assessment of OH density and overall chemical composition of modelled plasmas, if the air fraction, electron density and temperature are correctly determined.

Keywords

• global model
• atmospheric pressure plasmas
• oh radicals
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