RADIATIVE-TRANSFER CALCULATION IN SF6 ARC PLASMAS USING PARTIAL CHARACTERISTICS

The partial characteristics of the radiation which correspond to partial sources and partial sinks of radiation along a given direction, were calculated for a SF6 arc plasma between 3 000 and 30 000 K. These partial characteristics allow rapid calculation of the 3D radiative transfer in this type of plasma. The method was applied to several simple cases and showed the validity limits of the use of a net emission coefficient in the modelling of the arcs. It was shown that, to calculate the radiative transfer and the temperature in the hot regions, the use of a net emission coefficient is valid when the plasma is approximately isothermal. In the case of strong temperature gradients in the hot regions, the net emission coefficient depends strongly on the chosen plasma thickness whose value is difficult to estimate.