Numerical Modeling of Electric Discharges Generated in Supersonic Flows

A numerical solver is developed for the modeling of electric discharges in high-speed flows. For the formulation of the physicochemical model, common electric discharge modeling approaches are combined with detailed models for nonequilibrium aerothermodynamics and finite-rate chemical kinetics. The physicochemical model is based on the single-fluid assumption and takes into account the thermal and chemical nonequilibria in the gas mixture. For the numerical implementation, the finite-volume-based open-source CFD software package OpenFOAM is used. The verification of the calculation models for thermodynamic and transport properties as well as finite-rate chemical kinetics is carried out by means of one-dimensional simulations. The first validation of the solver is carried out by means of a three-dimensional simulation of an electric discharge with a constant input power of 10 kW generated on the surface of a wedge in a supersonic nitrogen flow. The numerically obtained results are compared with corresponding experimental measurements and theoretical calculations and show a fair agreement. The numerically calculated maximum temperature values, for example, are 20–40% above the measured values. However, it should be noted that the experimentally obtained values represent a spatial integration over the entire measurement volume and therefore do not indicate maximum temperature values.