MHD Modeling of the Tip-to-Plane Plasma Arc Behaviour at Very High Pressure in CF4

Abstract

In this paper, the behaviour of a tetrafluoromethane (CF4) plasma arc under conditions of low current (0.25–0.4 A) and very high pressure (10 and 50 atm) in a batch reactor is presented using a three-dimensional magnetohydrodynamic model. Our previous study provided an understanding to the influence of pressure on the experimentally observed instabilities in the horizontal configuration. For a deeper understanding of the influence of other plasma operating parameters on the instabilities observed for pure CF4, the interelectrode gap, as well as the operating current was investigated in this study. The interelectrode distance is investigated since, experimentally, the longer the arc, the more unstable. In case of a stable arc, it has been observed with the model that a higher pressure and a higher interelectrode distance leads to higher values in terms of quantity of gas treated and volumetric power; two parameters of significant interest to improve the efficiency of the process. In order to validate the results of the previous paper, original experiments were carried out successfully in a vertical configuration at pressures ranging from 10 to 50 atm. Indeed, the horizontal configuration does not permit the ignition of the arc discharge for pure CF4 at pressure higher than 3 atm. Thus, the potential of the high-pressure arc discharge for pure CF4 using the vertical configuration against the horizontal configuration is demonstrated.