1997 Volume 15 Issue 3 Pages 459-466
In this paper, energy balance of an argon-helium mixed gas tungsten arc was systematically discussed as corresponding to the demixing effect proposed in the previous reports.
Arc voltage increased as introducing helium gas into argon gas shielded arc. This tendency was caused by the increase of space potential near the cathode region in 75% below helium contents and the increase of potential gradient of arc plasma and space potential near the anode in almost pure helium content.
Anode heat input and thermal efficiency increased as introducing helium gas into argon gas shielded arc. It was found that the increase of anode heat input was independent on the energy transported by electrons, but was depend on the heat conduction and convection.
Furthermore, it was shown that the heat losses of the arcs reached to the minimum in 75% helium content. The results were caused by two phenomena that the radiative power decreased as increasing in the helium content, and the losses of heat conduction and convection gradually increased as increasing in the helium content and then steeply increased in almost pure helium content.