Experimental study of the discharge characteristics of a 3D vortex gliding arc plasmatron

Abstract

AbstractThe three‐dimensional (3D) vortex gliding arc plasmatron (GAP) is a promising gliding arc source due to its high reactant conversion rate and high energy efficiency, but there are few studies of its discharge characteristics. In this work, a 3D GAP device with a quartz window on the inner electrode is designed and studied. By means of high‐speed photography, high‐resolution current/voltage signal acquisition, and emission spectra, the effects of arc current, gas flow rate, electrode diameter, and electrode polarity on the discharge characteristics of this GAP are investigated. Results show that the volt‐ampere characteristic of GAP can be accurately predicted by similarity theory, and that the voltage for reverse‐polarity is significantly greater than that for normal‐polarity. Arc dynamics show that the arc at the inner electrode has the feature of high‐speed rotation, while the arc at the outer electrode has an extended current channel along with a large‐scale re‐strike process. The rotation speed and current channel length are closely related to electrode polarity, which can be ascribed to the movability of the cathode arc root. Emission spectra confirm that the plasma produced by GAP has typical non‐equilibrium properties, in which the rotational temperature ranges from 2,400 to 3,000 K and the vibrational temperature from 4,700 to 6,000 K. Moreover, abundant active free radicals, including NO, , O, and N, are detected in the plasma region. This investigation provides a better understanding of the discharge characteristics of 3D GAP, and will help to guide its further design and application.