Streamer Corona Discharge Induced by Laser Pulses During LIF Measurements in a DC Non-thermal Plasma Reactor for NO Oxidation
Streamer Corona Discharge Induced by Laser Pulses During LIF Measurements in a DC Non-thermal Plasma Reactor for NO Oxidation
复制标题
在用于 NO 氧化的直流非热等离子体反应器中进行 LIF 测量期间激光脉冲引起的流光电晕放电
DOI：
10.1515/jaots-2002-0201
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
J. Mizeraczyk
中科院分区：
文献类型：
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作者：
T. Ohkubo;Takeshi Ito;Yasuyuki Shuto;S. Akamine;S. Kanazawa;Y. Nomoto;J. Mizeraczyk
摘要实验研究了直流正电晕放电中激光诱导流光电晕发射的光与激光诱导荧光（LIF）信号在NO浓度测量中的可能干扰。对于原位NO测量，采用由XeF准分子激光器、染料激光器和BBO晶体组成的LIF系统，产生在226 nm处的调谐激光线。从所测量的规则流光电晕、激光脉冲、LIF信号和激光诱导流光之间的发生定时发现，LIF信号几乎在激光入射之后立即出现并且持续超过约30 ns，而诱导流光在LIF信号之后约35 ns开始并且持续约350-500 ns。由于LIF信号和激光诱导流光之间的5 ns间隔，LIF信号的不受干扰的检测可以通过适当调整ICCD相机的定时（门打开和曝光时间）来实现。利用激光诱导荧光技术测量了放电间隙中NO分子浓度的二维分布。利用ICCD相机对激光诱导流光的时间分辨演化进行了可视化，并进行了适当的定时调整。由此确定了拖缆的传播速度（约2.5 × 105 m/s）以及先导通道和先导拖缆的平均直径（分别为200 μm和100 μm）。
Abstract A possible interference of the light emitted by the laser induced streamer coronas and the laser induced fluorescence (LIF) signal during the measurements of NO concentration in a DC positive corona discharge was experimentally investigated. For in-situ NO measurement a LIF system consisting of a XeF excimer laser, dye laser and BBO crystal, generating a tuned laser line at 226 nm was employed. From the measured occurrence timing between the regular streamer coronas, laser pulse, LIF signal and laser induced streamer it was found that the LIF signal appears almost immediately after the laser incidence and lasts over about 30 ns, while the induced streamer starts about 35 ns after the LIF signal and lasts about 350-500 ns. Due to the 5 ns interval between the LIF signal and the laser induced streamer the undisturbed detection of the LIF signal can be possible with a properly adjusted timing of the ICCD camera (the gate opening and exposure time). Two-dimensional distribution of NO molecules concentration in the discharge gap was measured using the LIF technique. The time-resolved evolution of the laser induced streamers was visualized using the ICCD camera with the proper timing adjustment. This resulted in determining the velocity of propagation of the streamer (about 2.5 × 105 m/s) and the averaged diameters of the leader channel and leader streamers (200 μm and 100 μm, respectively).