PTFE掺杂浓度对高温CO2气体物性参数的影响

As one of the potential alternatives of SF6 gas which produces a remarkable greenhouse effect，CO2 gas has been adopted by circuit breaker as insulation and arc⁃extinguishing medium. In fact，PTFE vapor resulting from nozzle ablation may modify fundamental properties of plasma，which then has an effect on interruption performance of circuit breaker. The determination of plasma fundamental properties is the prerequisite to arc physical modeling es⁃ tablishment and interruption performance optimization for circuit breaker. Thus，this paper investigates the funda⁃ mental properties of CO2 ⁃ PTFE thermal plasma for the temperature range 300-30，000 K under 0.6 MPa. First， Gibbs free energy minimization method is utilized to determine plasma equilibrium composition which then uses to determine thermodynamic properties with standard thermodynamic equations. Finally，transport coefficients（electri⁃ cal conductivity，thermal conductivity and viscosity）for CO2⁃PTFE plasma is calculated based on Chapman⁃Enskog theory. It can be observed that PTFE modifies plasma fundamental properties. More specifically，PTFE results in a dramatic influence on viscosity，thermal conductivity and electrical conductivity at low temperature for CO2 ⁃PTFE thermal plasma and the influence of PTFE with a small proportion（less than 25%）on electrical conductivity is limited.