Optical study of temperature characteristic and NO oxidization process by OH radicals in DBD by Optical Emission Spectroscopy

The optical spectroscopy characteristic of dielectric barrier discharge( DBD) plasma in NO /H2O / N2mixture was studied by Optical Emission Spectroscopy( OES). DBD plasmas was generated in a 4mm wire-cylinder gap in atmospheric- pressure,spectrum of NO( A2Σ + →X2Π,0- 3,1- 4),N2( C3Πu→B3Πg,0- 0) and OH( A2Σ+→X2Π,0-0) was observed. The plasma gas temperature was determined by comparing the experimental spectrum and the best fitted spectrum. From the NO( A2Σ + →X2Π,0-3,1-4) rotational transition band,the temperature was about 320K. One-dimensional distribution of NO( A2Σ+→X2Π,0-3) and N2( C3Πu→B3Πg,0-0) emission intensity was obtained. When RH = 20%,OH emission intensity reached the maximum. As the peak voltage increased,NO( A2Σ + →X2Π,0-0) and OH( A2Σ+→X2Π,0- 0) emission intensity rised. As the RH increased,NO emission intensity decreased,emission intensity decreased about 93% when RH = 100% compared with RH = 20%; NO concentration increased,OH emission intensity decreased,emission intensity decreased about 27% at NO concentration of600mL / m3compared with NO concentration of 200mL / m3,which could reveal the importance of OH radicals in NO conversion process.