Modeling and Simulation of Low Current Atmospheric and High-Pressure Helium Plasma Discharges

Abstract

A plasma discharge in a Helium gas reactor at different pressures and at low currents (0.25–0.45 A) has been investigated by Computational Fluid Dynamic modeling coupled with the Maxwell’s equations. The results show different discharge dynamics across the pressure range (0.1–8 MPa), with an arc discharge obtained at high pressure and a low current arc discharge observed at atmospheric pressure. A large density gradient at higher pressure causes a strong natural convection effect in the reactor. This density gradient affects drastically the discharge shape and the velocity field at high pressures while at atmospheric pressure, a lower density gradient was observed resulting in a low velocity magnitude. It has been observed that the velocity magnitude is not affected by the electric current. The discharge electric potential has been calculated by considering the electrical characterization of the electrodes and numerical results have been compared with experimental results. The comparison shows a good agreement between the measured and calculated discharge electric potential at lower pressures. These devices can be used as plasma sources for wastewater treatment.

Modeling and Comparative Analysis of Atmospheric Pressure Anodic Carbon Arc Discharge in Argon and Helium–Producing Carbon Nanostructures

“…To date, there are various models of arc discharges in 0D [ 32 ], 1D and 2D formulations in the framework of LTE and non-LTE approximations. For quite a long time, it was the LTE approximation that was used in modeling arc discharges, which is still used in scientific research [ 33 , 34 , 35 , 36 , 37 ]. On the other hand, a series of experimental and theoretical works showed a deviation from the local thermodynamic equilibrium [ 38 , 39 , 40 ] at the periphery of the arc discharge and in the near-electrode regions.…”