NUMERICAL MODELLING OF A PLASMA TORCH. COMPARISON WITH EXPERIMENTAL RESULTS

This paper presents a comparison between experimental and theoretical studies of a DC plasma torch. A mathematical 2D model including both the arc and plume regions was developed by using Patankar's resolution method. In parallel, emission spectroscopy was performed on an identical DC plasma torch geometry for the temperature determination of the plume. The plasma gas is argon and the ambient gas is air or argon at atmospheric pressure. The results of the experiments and of the code give similar behaviours such as an increase of the temperature on the axis with an increase of the arc current. The rise of inlet gas flow rate tends to constrict the plasma leading to a heating of the axis region. The radial temperature gradients were sharper in air than in argon. Due to the differences on thermal conductivity and heat capacity, the cooling effect is more pronounced in air than in argon.