Calculation of thermodynamic properties and transport coefficients of C₅F₁₀O-CO₂ thermal plasmas

The thermodynamic properties and transport coefficients of C₅F₁₀O-CO₂ gas mixtures, which are being considered as substitutes for SF₆ in circuit breaker applications, are calculated for the temperature range from 300 K to 30 000 K and the pressure range from 0.05 MPa to 1.6 MPa. Special attention is paid on investigating the evolution of thermophysical properties of C₅F₁₀O-CO₂ mixtures with different mixing ratios and with different pressures; both the mixing ratio and pressure significantly affect the properties. This is explained mainly in terms of the changes in the temperatures at which the dissociation and ionization reactions take place. Comparisons of different thermophysical properties of C₅F₁₀O-CO₂ mixtures with those of SF₆ are also carried out. It is found that most of the thermophysical properties of the C₅F₁₀O-CO₂ mixtures, such as thermal conductivity, viscosity, and electrical conductivity, become closer to those of SF₆ as the C₅F₁₀O concentration increases. The composition and thermophysical properties of pure C₅F₁₀O in the temperature range from 300 K to 2000 K based on the decomposition pathway are also given. The calculation results provide a basis for further study of the insulation and arc-quenching capability of C₅F₁₀O-CO₂ gas mixtures as substitutes for SF₆.