INFLUENCE OF DEMIXING EFFECT ON THE TEMPERATURE IN WALL-STABILIZED SF6 ARCS

The demixing effect in a SF6 wall-stabilized are leads to sulphur depl etion in the central part of the are where the ratio between fluorine concentration and sulphur concentration becomes higher than six We hav e calculated material functions for different real or fictitious gases SFM, with 6 less than or equal to M less than or equal to 15 (specifi c heat, electrical and thermal conductivities, net emission coefficien t) and used them in a one-dimensional model based on Patankar's algori thms. The electric field and the temperature radial profile have been calculated versus the current intensity using 5 mm and 3.2 mm are diam eters. Comparison with experimental results in the literature shows th at the influence of demixing on the axis temperature is greater than t he experimental error. Thus, we conclude that validating material func tions of SF6 plasma by comparing experimental and theoretical values o f temperature in wall-stabilized arcs needs to take into account demix ing effects.