Eur. Phys. J. D (2015) 69: 223
https://doi.org/10.1140/epjd/e2015-60163-y

Regular Article

Light emission spectra of molecules in negative and positive back discharges in nitrogen with carbon dioxide mixture at atmospheric pressure

Institute of Fluid Flow Machinery Polish Academy of Science, ul. Fiszera 14, 80-231 Gdańsk, Poland

^a e-mail: czech@imp.gda.pl

Received: 11 March 2015
Received in final form: 5 August 2015
Published online: 6 October 2015

Abstract

Results of spectroscopic investigations and current-voltage characteristics of back discharge generated in point-plane electrode geometry with plate covered fly ash layer in a mixture of N₂ + CO₂ at atmospheric pressure, for positive and negative polarity of the discharge electrode are presented in this paper. Point-plane electrode configuration was chosen in these studies in order to simulate the physical processes occurring in electrostatic precipitator. Three forms of back discharge for both polarities were investigated: glow, streamers and low-current back-arc. Diatomic reactions and dissociation products of N₂ and CO₂ (OH, NO, CN), atoms from fly ash layer (N, Ti, Na), free radicals, molecules or ions, which have unpaired valence electrons, and other active species, e.g., N₂ (in C,B,A-state), N (B) were identified in the discharges by the method of optical emission spectroscopy (OES). The measurements shown that atomic and molecular optical emission spectral lines from back discharge depend on the forms of discharge and the discharge current. In normal electrical discharges, the emission spectra are dominated by gaseous components, but in the case of back discharge, atomic lines belonging to chemical compounds of fly ash were also recorded and identified.