空气介质阻挡放电发射光谱测量及放电过程粒子分析

摘要

发射光谱是对等离子体进行检测和诊断最常见的应用方法 ,提供了等离子体的化学和物理过程丰富的信息 ,放电过程中等离子的动力学行为的分析研究对于气体放电机理及其应用具有重要的作用.设计了一套介质阻挡空气放电光谱测量装置 ,测量了在实验条件下的发射光谱数据 ,通过发射光谱分析了介质阻挡放电等离子体的粒子演化.建立了数值计算模型 ,耦合了密度方程、能量传递方程以及Boltzmann方程 ,对于介质阻挡空气放电过程中的各种粒子变化规律进行了分析 ,解释了发射光谱的特征.结果表明 ,约化场强越大 ,激发的粒子数的浓度越大.对于40 ,60与80 T d的约化场强 ,同一时刻同种粒子数的浓度会有一到两个数量级的差距.电场的激发产生了大量的N2 (A3 ) ,N2 (B3 )与N2 (C3 )的粒子 ,但是由于其能级较高 ,而迅速发生了转化 ,并且在放电的10-6 s后 ,这些粒子的产生与转化达到了平衡.相比激发态氮分子 , O2 (A1 ) O2 (B1 )与O2 (A3Σ+u )的峰值浓度并不低 ,这些粒子的能量相对较低 ,跃迁产生的谱线波长较长 ,光谱仪并未清晰捕捉到氧分子的发射光谱.O粒子的峰值浓度较小 ,因此其跃迁产生的发射光谱较弱.放电过程中产生的较为稳定的O3 浓度持续增加 ,NO2 的浓度达到峰值后也不会下降.建立的模型计算结果可以很好地解释实验中测量得到的发射光谱数据.%The emission spectrum detection and diagnosis is one of the most common methods of application to the plasma .It provides wealth of information of the chemical and physical process of the plasma .The analysis of discharge plasma dynamic be-havior plays an important role in the study of gas discharge mechanism and application .An air dielectric discharge spectrum measuring device was designed and the emission spectrum data was measured under the experimental condition .The plasma par-ticles evolution was analyzed from the emission spectrum .The numerical calculation model was established and the density equa-tion ,energy transfer equation and the Boltzmann equation was coupled to analyze the change of the particle density to explain the emission spectrum characteristics .The results are that the particle density is growing with the increasing of reduced electric field .The particle density is one or two orders of magnitude difference for the same particle at the same moment for the reduced electric field of 40 ,60 or 80 Td .A lot of N2 (A3 ) ,N2 (A3 ) and N2 (C3 ) particles are generated by the electric field excitation . However ,it transforms quickly due to the higher energy level .The transformation returns to the balance after the discharge of 10-6 s .The emission spectrometer measured in the experiments is mostly generated by the transition of excited nitrogen .The peak concentration of O2 (A1 ) ,O2 (B1 ) and O2 (A3Σ+u ) is not low compared to the excited nitrogen molecules .These particles energy is relatively low and the transition spectral is longer .The spectrometer does not capture the oxygen emission spectrum . And the peak concentration of O particles is small ,so the transition emission spectrum is weak .The calculation results of the stabled model can well explain the emission spectrum data .