Calculation of Thermodynamic Properties and Transport Coefficients of C4F7N–PTFE Mixtures

The thermodynamic properties and transport coefficients of C4F7N–PTFE gas mixtures in the temperature range from 300 to 30,000 K and the pressure range from 0.1 to 1.6 MPa are calculated. Special attention is paid to the effects of different PTFE ratios and gas pressures on the physical properties of C4F7N–PTFE mixed gases. The composition of arc plasma particles was determined based on the principle of minimizing Gibbs free energy, and the thermodynamic parameters and transport coefficients were determined by standard thermodynamic equations and Chapman-Enskog theory. It can be concluded that the addition of PTFE will have a certain degree of impact on the specific heat at constant pressure and thermal conductivity of the mixture. However, due to the compositional similarity between C4F7N and PTFE elements, a small amount of PTFE is not expected to result in significant changes to the performance of the plasma. Elevating the gas pressure can lead to an augmentation of the transport coefficients, particularly within the domain of elevated temperatures. The calculation results provide basic data for the simulation of plasmas using magnetohydrodynamics arc models, also provide a reference for the design of environmentally-friendly high-voltage circuit breakers; some examples are presented.