Thermodynamics and transport properties of metal/inert-gas mixtures used for arc welding

Abstract

The knowledge of thermodynamics and transport properties of gas mixtures at high temperature is important for many industrial applications. Spark ignition, re-entry problems of space-vehicles, gas dischargers, arc welding, and circuit breakers can be mentioned as examples. This paper focuses on metal/inert-gas mixtures in the temperature range from 300 to 30,000 K, which are important for arc welding processes. As metals we consider iron, copper, aluminium, and calcium and as inert gases nitrogen, argon, and helium. The results are validated by comparison with transport properties from literature. Furthermore, this study also significantly extends and improves the transport model developed earlier [S. Selle, U. Riedel, Ann. NY Acad. Sci. 891 (1999) 72–80; J. Prager, G. Baldea, U. Riedel, J. Warnatz, Equilibrium Composition and Electrical Conductivity of High-Temperature Air, 21st ICDERS (2007); J. Prager, U. Riedel, J. Warnatz, Proc. Combust. Inst. 31 (2007) 1129–1137]. The transport properties are calculated using Chapman–Enskog theory. The model is universally applicable and needs little input data. A multicomponent mixture formulation or simple mixing rules can be used.