Thermodynamic properties and transport coefficients of C4F7N/CO2 thermal plasma as an alternative to SF6

Abstract

The paper is devoted to the calculation of equilibrium compositions, thermodynamic properties (mass density, enthalpy and specific heat at constant pressure) and transport coefficients (electrical conductivity, viscosity and thermal conductivity) of C4F7N/CO2 thermal plasma. Assuming local thermodynamic equilibrium, the species composition is determined using the principle of minimization of the Gibbs free energy. The transport properties are calculated by the Chapman-Enskog method. Some recently updated cross-sections or interaction potentials in the literature is adopted to obtain collision integrals. These data are computed in the temperature range between 300 K-30 kK, for a pressure between 0.1 MPa and 1 MPa and for several CO2 proportions. Transport coefficients of pure CO2 plasma are also compared with previously published values. The results clarify some basic chemical process in C4F7N/CO2 mixtures and provide reliable reference data for the arc simulations.