Atmospheric Pressure Dielectric Barrier Discharge Emission Spectrometry Diagnostics,

Atmospheric pressure dielectric barrier discharge is a kind of non-local thermodynamic equilibrium plasmas. It has a number of important industrial applications. In this work, a set-up of atmospheric pressure dielectric barrier discharges had been established and its discharge mechanism had been diagnosticated by measuring its figure of voltage and current, Lissajous figure and temporal resolution spectrum. Three discharge modes of filamentary, homogeneous and glow discharge can appear at different conditions.Optical emission spectroscopy is a in-situ, real-time, on-line and non-disturbed high temporal-spatial resolution diagnostic method. In this paper, atmospheric pressure dielectric barrier discharges in N2 and N2+O2, N2+Ar, N2+He had been diagnosticated by this technique. The experimental results are as follows:1, Optical emission spectrum of atmospheric pressure dielectric barrier discharges in N2 had been measured . The relationships between the intensity of N2(C3Пu-B3Пg)and gas flow, electrode gap, voltage and frequency of power supply had been obtained. It was found that the intensity of N2(C3Пu-B3Пg)had a maximum value when gas flow rate was 300mL/min or electrode gap was 1.5mm. The intensity of N2(C3Пu-B3Пg)increased with the increasing of voltage or frequency of power supply, but the intensity of N2(C3Пu-B3Пg)had a sharp increasing when the voltage or frequency of power supply increased to some extent, then the filamentary dielectric barrier discharges transferred into homogeneous dielectric barrier discharges.2, Optical emission spectra of atmospheric pressure dielectric barrier discharges in N2+O2, N2+Ar, N2+He had been measured and explained3, O2 can quench excited N2 species at atmospheric pressure dielectric barrier discharges in N2+O2, but there are no quenching selectivity on excited N2 species for O2. NO can be produced in atmospheric pressure dielectric barrier discharges in N2+O2 when concentration of O2 is below 5%. The intensity of NO(A-X) decreases exponentially with the increasing of concentration of O2 .The results have an important reference value in analysis of the mechanism of de-NOX.4, Energy transfer should be the main pathway for excition of N2 in atmospheric pressure dielectric barrier discharges in N2+Ar, N2+He. Energy transfer efficiency to N2 is larger for He than for Ar. Energy transfer selectivity is higher for Ar than for He. The reason may be the energy of Ar metastable is near the energy of excited N2 species. N2 can quench the excited Ar or He , The rate of quenching for He is larger than that for Ar. And the quenching selectivity for He is larger than that for Ar, the reason may be N2 has a high vibration state .5, The excited temperature of He in He atmospheric pressure dielectric barrier discharges varies from 2500K to 4200K with the increasing of voltage from 3KV to 7KV. It increases linearly with the increasing of the voltage, but the gas temperature is always at about room temperature.