206 / 2024-04-17 11:12:06

Thermodynamic and transport Properties of Non-equilibrium C4F7N Plasmas

High-voltage circuit breakers,Arc,C4F7N,Two-temperature plasma,Thermodynamic properties,Transport coefficients

High-voltage gas circuit breakers are essential for maintaining the stability of power systems. Due to the strong greenhouse effect of SF₆ arc extinguishing medium, C₄F₇N mixture has become one of the most promising alternatives. In this work, a computational framework for thermodynamic properties and transport coefficients of two-temperature arcs in C₄F₇N plasma at critical interruption moments in the current-zero region is established. The non-equilibrium phenomena of C₄F₇N plasma are investigated to reveal the particle evolution behavior and physical properties under non-equilibrium conditions. The results indicate that with increasing non-equilibrium degree, the dissociation process of C₄F₇N molecules is suppressed, and the peak of specific heat at constant pressure of the plasma shifts towards higher temperatures. A higher non-equilibrium degree leads to a larger contribution of chemical reactions to gas thermal conductivity, resulting in a significant increase in the peak of thermal conductivity. Additionally, due to the lesser impact of heavy particle collisions on electron mobility, the conductivity of non-equilibrium plasma increases to some extent in the high-temperature region. Both increasing pressure and non-equilibrium phenomena hinder chemical reactions, while higher pressure increases the particle density per unit volume, thereby leading to higher conductivity and viscosity. The results provide fundamental parameters for magnetohydrodynamic simulations of non-equilibrium arcs.