Eur. Phys. J. D (2016) 70: 233
https://doi.org/10.1140/epjd/e2016-70241-3

Regular Article

Effects of copper vapour on thermophysical properties of CO₂-N₂ plasma

¹ State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, No. 28 Xianning West Road, Xi’an, Shaanxi Province 710049, P.R. China
² LAPLACE (Laboratoire Plasma et Conversion d’Énergie), Université de Toulouse, CNRS, UPS, INPT, 118 route de Narbonne, 31062 Toulouse, France

^a e-mail: xhw@mail.xjtu.edu.cn
^b e-mail: cressault@laplace.univ-tlse.fr

Received: 5 April 2016
Received in final form: 20 June 2016
Published online: 3 November 2016

Abstract

CO₂-N₂ mixtures are often used as arc quenching medium (to replace SF₆) in circuit breakers and shielding gas in arc welding. In such applications, copper vapour resulting from electrode surfaces can modify characteristics of plasmas. This paper therefore presents an investigation of the effects of copper on thermophysical properties of CO₂-N₂ plasma. The equilibrium compositions, thermodynamic properties (including mass density, specific enthalpy, and specific heat), transport coefficients (including electrical conductivity, viscosity, and thermal conductivity), and four kinds of combined diffusion coefficients due to composition gradients, applied electric fields, temperature gradients, and pressure gradients respectively, were calculated and discussed for CO₂-N₂ (mixing ratio 7:3) plasma contaminated by different proportions of copper vapour. The significant influences of copper were observed on all the properties of CO₂-N₂-Cu mixtures. The better ionization ability and larger molar mass of copper and larger collision integrals related to copper, should be responsible for such influences.