381 / 2017-04-20 15:44:55

Composition and thermodynamic properties of air thermal plasmas mixed with ablated Copper and polytetrafluoroethylene vapor and simulation of arcing process

In order to study the characteristic of fault arc in aircraft electrical system, this paper is devoted to calculate chemical equilibrium composition and thermodynamic properties (mass density, enthalpy and specific heat at constant pressure) of reacting mixtures contained by air, Cu and polytetrafluoroethylene at temperatures of 300–3 000 K and pressures of 0.02–0.1 MPa and simulate the corresponding arc process. Under the assumption of local thermodynamic equilibrium, chemical equilibrium composition is solved by the method of Gibbs free energy minimization together with Lagrange multiplier. Debye–Hückel corrections are applied to the free energies of ionized species. Thermodynamic properties are obtained by the standard thermodynamic relationships. The simulation of the arcing process of the fault arc is carried out by the magneto-hydrodynamic arc model, which lays the theoretical foundation for the study of ablation and protection characteristics of fault arc.