脉冲电晕放电电子能量及OH,O或O_3对NO氧化的光谱学研究

Diagnosis of Electron Energy and Comparative Effects of OH,O or O_3 on NO Oxidation in Pulsed Corona Discharge

采用发射光谱法测量了线板式脉冲电晕放电中激发态氮气分子N2*和离子N2+的光谱强度,并与数值计算获得的结果进行对比,确定放电电场的空间分布及平均电子能量。水平与竖直方向离开线电极0～2cm,随着距离的增加,平均电子能量和电场均呈先减后增的变化趋势;放电电场变化范围11.05～19.6MV.m-1,对应的平均电子能量的变化范围10.10～13.92eV。这一能量水平的电子足以与O2,H2O分子碰撞产生O,OH自由基,并进一步反应生成O3。在NO氧化过程中,NO可与OH自由基共存,但不能与O3共存;且O3或O氧化NO的效率高于OH自由基,推断O3或O在NO的氧化过程中起关键作用。

The spectrum of excited N2 molecules and ions was measured by optical emission spectroscopy in pulsed corona discharge with a wire-to-plate reactor.The ratio of emission intensities emitted by the excited molecules and ions of N2 was compared with numerical simulation to determine average electron energies and electric field distributions.Within 2 cm distance from wire electrode in horizontal and vertical directions,electric field and average electron energies appear to be in the ranges of 11.05~19.6 MV·m-1 and 10.10~13.92 eV respectively;as the distance increases,average electron energies and electric field show a similar trend： first decrease and then increase.Chemically active species,such as OH,O and O3,can be generated through the energetic electron collisions with H2O and O2 directly or indirectly.For the NO oxidation,there is no coexistence of NO and O3,whereas there is a coexistence of NO and OH.NO is oxidized by O3 or O more efficiently than by OH radical.