The influence of graphite on the composition and thermodynamic properties of plasma formed in ablated vapour of PMMA, PA6-6, PETP, POM and PE used in circuit-breakers
Résumé
With the Gibbs free energy minimization method, we determine the mole fraction of graphite in plasmas formed in the insulator vapours of PMMA, PA6-6, PETP, POM and PE at LTE. By an approximate method, we compare theoretically the proportion of graphite during the quenching of the electric discharge occurring in circuit breakers. In the temperature range 1000 - 5000 K, the composition and thermodynamic properties (specific enthalpy, specific heat capacity and density) of the plasma phase are given. The results are discussed and compared with those obtained without taking the graphite into account.