锯齿波频率对介质阻挡放电光谱特性的影响

采用微间隙平行平板介质阻挡放电(DBD)装置，以氩气作为工作气体，研究了锯齿波激励下DBD的放电图像、发光信号、发射光谱与锯齿波频率的关系。研究发现随锯齿波频率增加，DBD会从均匀模式(低于10 kHz)，经历微放电丝与均匀放电共存，并最终过渡到微放电丝占据全部的电极区(频率高于35 kHz)。外加电压和发光波形表明，锯齿波频率较低时的均匀放电对应高占空比的阶梯放电。随频率增大，出现微放电丝后，发光波形呈现多脉冲形式，且电压半周期中的发光脉冲个数随着锯齿波频率的增大而减小。当锯齿波频率高于35 kHz时，每半个电压周期的发光脉冲个数减小为一个(单脉冲放电)。通过对放电的发射光谱进行研究，发现发射光谱中包含氮分子的第二正带系(C3Π_u→B3Π_u)，OH(A2Σ+→X2Π)和ArI的特征谱线。研究表明OH(308.8 nm)和ArI(750.4 nm)的谱线强度均随锯齿波频率的增大而增大。

Effect of Frequency on Spectral Charteristics of Dielectric Barrier Discharge Excited by a Saw-Tooth Voltage

Using a micro-gap dielectric barrier discharge (DBD) decive in a parallel plate geometry, the frequency of the saw-tooth voltage has been varied to investigate the discharge image, the light emission signal and the optical emission spectrum of the DBD by using argon as the working gas. It is found that with increasing frequency of the saw-tooth wave, DBD could be in a diffuse mode less than 10 kHz, then it transits to many micro-discharge filaments occupying the whole electrode area (higher than 35 kHz) after the coexistence of micro-discharge filaments and diffuse discharge. Waveform of the applied voltage and the light emission indicates that, at a lower saw-tooth wave frequency, the diffuse discharge emits a stepped light emission signal with a high duty ratio. When increasing the saw-tooth wave frequency, the light emission transits into a multi-pulsed mode after the emergence of micro-discharge filaments. Moreover, the number of the light pulses per half voltage cycle decreases with increasing the driving frequency. The light pulse number presents one per half voltage cycle (single pulsed discharge) when the saw-tooth wave frequency is higher than 35 kHz. Scanning the optiacl spectra of the discharge, it can find the second positive system of nitrogen molecule(C3Π_u→B3Π_u), OH(A2Σ+→X2Π) and ArI. The spectral intensity of OH (308.8 nm) and ArI (750.4 nm) is investigated as a function of the saw-tooth wave frequency, and the results show that they both increase when increasing the saw-tooth wave frequency.