Transient Flowfield Characteristics of Polycarbonate Plasma Discharge from Pulse-Powered Electrothermal Gun Operation

摘要

An electrothermal gun is the device that produces high-temperature and high-velocity plasma vapor using high current pulsed power and has a potential to be an efficient method for producing a variety of nanomaterials. Pulsed plasma discharge from the electrothermal gun into the open air has been investigated numerically, and the time-dependent inviscid gas dynamics equations are solved for the two-dimensional computational domain including electrothermal gun and the open-air space using flux-corrected transport (FCT) scheme. The modeling of the Joule heating and the mass ablation from the bore wall are incorporated in the computation. The computational results yield the details of the plasma discharge behavior inside and outside the capillary bore including choked condition at the bore exit and complex shock structure of external plasma discharge. The flow structure of freely expanding plasma discharge in the open air is essentially the highly underexpanded supersonic jet featuring Mach disk, barrel shock, contact surface, and spherical blast wave. Compared to the experiments, the numerical simulation agrees well with the experimental data such as the capillary mass ablation and shock structure of the plasma jet.