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.
