Arc characteristics and tungsten electrode condition under the action of gas flow flexible constraint

This work aims to elucidate the physical characteristics of the arc and the state of the tungsten electrode under the constraint effect of gas flow. Tungsten electrodes containing the elements Ce, Zr, La, and Th were selected for the study. Through high-speed imaging, spectral diagnostics, and numerical simulations, the distribution patterns of the physical fields of the arc were obtained. Compared to pure tungsten, tungsten electrodes containing trace elements are more resistant to erosion and better maintain their integrity. The differences among electrodes with various trace elements are relatively small. When a constrained gas flow is introduced, the arc contracts, and the arc contraction range is 5.8%–8.6%. The gas flow not only increases the energy density of the arc but also provides cooling effect. Changes in the gas flow rate alter the dominance of these two effects, thereby influencing the arc width. By combining the surface morphology of the tungsten electrode with the results of numerical simulations, it is found that the constrained gas flow can effectively inhibit the diffusion of metal vapor. When the gas flow rate is 1–2 l/min, the concentration of metal vapor can be reduced by 75%; when the gas flow rate exceeds 3 l/min, its concentration will increase again. In addition, the degree of metal vapor diffusion under different gas flow rates may be another factor contributing to the changes in arc width.