| High-voltage pulsed corona discharge plasma has been widely studied in the removal of toxic pollutant, the removal of acid gases from flues gas, and other environment management. The radicals and active spices produced by the pulsed corona discharge play important role in the removal process. Especially, OH radicals with their stronger oxidation play the central role in many physicochemical processes.In this article, the OH radials produced by positive and bi-directional pulse corona discharge in a wire-plate reactor are studied by emission spectra technology I . The emission spectra of OH (A2∑→X2П , 0-0) radicalsThe emission spectrum of OH (A2∑→X2П , 0-0) emitted from the high-voltage positive and bi-directional pulse corona discharge of N2 and H2O mixture gas in a wire-plate reactor is successfully recorded. And in the humid air, the emission spectrum of OH (A2∑→X2П, 0-0) emitted from the high-voltage positive pulse corona discharge has also been obtained.II. The calculation of the relative population of the OH radicalsThe relative vibration population and the vibration temperature of N2(C, v') are obtained by the emission intensity of the Av = -3 and Av = -4 vibration transition band of N2 (C3Пu→B3Пg). The emission spectrum of the Av = +1 (1-0, 2-1, 3-2, 4-3) vibration transition band of N2 (C3Пu →B3Пg) is simulated through gauss distribution. The emission intensity of OH (A2∑→ X2П, 0-0) has been exactly gotten by subtracting the emission intensity of the Av = +1 vibration transition band of N2 (C3Пu→ B3Пg) from the overlapping spectra. The relative population of OH (A2∑) can be obtained by the emission intensity of OH (A2∑→X2П, 0-0).III. The influences of the discharge voltage, discharge frequency and the added O2 on the production of the OH radicalsThe influences of peak voltage, discharge frequency of the positive and the bi-directional pulse discharge and the added O2 on the emission intensity and the relative population of the OH radicals produced in the N2 and H2O mixture gas have been studied. The effects of the positive pulse peak voltage and frequency on the relative population of the OH radicals produced in the humid air have also been investigated. Moreover, the important physicochemical reaction processes of active spices have also been discussed.The experimental results indicate that: the emission intensity of the OH radicals increase with increasing the peak voltage and the frequency, and decrease with increasing the O2 flow rate; the relative population of the OH radicals increase linearly with increasing the peak voltage and the frequency, and decrease exponentially with increasing the flow rate of added oxygen.
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