Gas flow dependence of atmospheric pressure plasma needle discharge characteristics

Abstract

In this paper, a two-dimensional coupled model of neutral gas flow and plasma dynamics is presented to explain the gas flow dependence of discharge characteristics in helium plasma needle at atmospherics pressure. The diffusional mixing layer between the helium jet core and the ambient air has a moderate effect on the streamer propagation. The obtained simulation results present that the streamer shows the ring-shaped emission profile at a moderate gas flow rate. The key chemical reactions which drive the streamer propagation are electron-impact ionization of helium neutral, nitrogen and oxygen molecules. At a moderate gas flow rate of 0.5 slm, a significant increase in propagation velocity of the streamer is observed due to appropriate quantity of impurities air diffuse into the helium. Besides, when the gas flow rate is below 0.35 slm, the radial density of ground-state atomic oxygen peaks along the axis of symmetry. However, when the gas flow rate is above 0.5 slm, a ring-shaped density distribution appears. The peak density is on the order of 1020 m−3 at 10 ns in our work.

Influence of operating conditions on electron density in atmospheric pressure helium plasma jets

“…N 2 (V) and O 2 (V), are also considered. Previous studies [30,42] have demonstrated that photoionization is unnecessary for this discharge model to be sustained if a sufficient background electron density (10 8 -10 16 m −3 ) is present. Hence, we set the initial electron density to 10 15 m −3 in this study.…”

A review of the gas and liquid phase interactions in low-temperature plasma jets used for biomedical applications

“…The choice of feeding gas has a major impact on the physicochemical processes at play. For example, the role played by the Penning ionisation in helium fed APPJs has increased the propagation speed of an IW, compared to that observed in argon for similar configuration [35,97]. While the flow rate does not directly affect the physical properties of the jet, it influences the mixing of impurities downstream of the capillary and thus is able to impact ionisation and attachment processes altering the charge density and the electric field distribution [85,98].…”

Global modeling on partial oxidation of methane to oxygenates and syngas in non-equilibrium plasma

“…In our previous works, 2D axisymmetric fluid model was used to study discharge characteristics of methane-air plasma jet. 39,40) Although only less than 100 chemical reactions are taken into account in 2D fluid model, calculation efficiency is still very low. The reason is that simulation process requires a lot of iterative calculations for 2D fluid model, which is very demanding on hardware resources.…”