Temperature Measurement of Tungsten Electrode Surface at Electric Arc Extinction in Air–Power Flux Estimation

This paper deals with temperature measurements of the surface of tungsten electrodes submitted to electric arcs in nonstationary regimes in air at atmospheric pressure and with the estimation of the power and power density brought by electric arcs to the electrodes. Temperature measurements are proposed for tungsten anodes and cathodes for current intensity of ~30 A and duration of 3 ms. The temperature of the electrode surface at the instant the arc extinguishes is estimated in both electrode polarities. These experimental results are used in a model to estimate the power and the power density brought to the tungsten electrode surface by electric arcs. We found that the power surface density brought by electric arcs to the electrodes was in the range 1. × 10⁹-1.5 × 10⁹ W/m² in the case of anodes and in the range 1.3×10⁹-1.9×10⁹ W/m² in the case of cathodes. It has also been found that reactions of tungsten oxidation had to be considered to explain the high values obtained for the power brought to the electrodes.