Prediction of the critical reduced electric field strength for carbon dioxide and its mixtures with copper vapor from Boltzmann analysis for a gas temperature range of 300 K to 4000 K at 0.4 MPa

The influence of copper vapor mixed in hot CO₂ on dielectric breakdown properties of gas mixture at a fixed pressure of 0.4 MPa for a temperature range of 300 K-4000 K is numerically analyzed. First, the equilibrium composition of hot CO₂ with different copper fractions is calculated using a method based on mass action law. The next stage is devoted to computing the electron energy distribution functions (EEDF) by solving the two-term Boltzmann equation. The reduced ionization coefficient, the reduced attachment coefficient, and the reduced effective ionization coefficient are then obtained based on the EEDF. Finally, the critical reduced electric field (E/N)_cr is obtained. The results indicate that an increasing mole fraction of copper markedly reduces (E/N)_cr of the CO₂-Cu gas mixtures because of copper's low ionization potential and large ionization cross section. Additionally, the generation of O₂ from the thermal dissociation of CO₂ contributes to the increase of (E/N)_cr of CO₂-Cu hot gas mixtures from about 2000 K to 3500 K.