Optical and electrical measurements of a novel dielectric barrier discharge system exhibiting species gain

Abstract

Summary form only given. In this paper, optical and electrical measurements of a novel multi-electrode dielectric barrier discharge (DBD) plasma system exhibiting active species gain are performed. This gain in species density is accomplished by arranging four electrode pairs vertically and forcing compressed air through their volumes. This forces the filamentary striations together through lateral pressure, thus aiding in the formation of an extremely dense plasma. The multi-electrode system operates in an effective feed-forward mechanism to create a denser plasma than reported previously. By increasing the initial conditions for oxygen metastables and radicals and other reactive species at each electrode pair, the overall density is increased also for successive electrode pairs. Optical measurements are performed by means of a photomultiplier tube with a quartz window (electron tubes module P30232-07) in order to analyse the deep UV region of the spectrum accurately. These are taken at each of the four electrode stages and at the output of the system. The copious quantities of ozone produced in this DBD plasma are evident from focusing in on the 250-260 nm regime and analysing the associated optical emissions. In addition, the electrical measurements from the quad IGBTs acting as the drive circuitry are analysed and drive circuitry is outlined to create as noiseless an environment as possible. Results indicate that the optical emission around the 250 nm mark throughout the system increases thus showing the increase in the concentration of species with this characteristic wavelength from one plasma volume to the next. The output of the system shows a high density of these species, gradually diminishing as diffusion takes over. The need for compressed air is additionally highlighted by the individual DBD striations being clearly visible when it is not applied. This results in little or no species gain as no accelerant exists in the system. This research has enormous potential in industrial applications due to the high concentration of ozone produced coupled with the prospective in-line set-up of the system.