为了进一步揭示等离子体强化甲烷点火过程的化学动力学机理, 设计和搭建了介质阻挡放电等离子体激励空气的实验系统, 实验测量了在空气中介质阻挡放电等离子体激励器产生的发射光谱, 利用光谱技术分析了等离子体激励空气产生的若干活性粒子, 给出了零维均质点火模型以及敏感性分析和化学路径分析的计算方法, 模拟了不同初始温度下NO和O3对甲烷点火延迟时间的影响, 并分析了活性粒子NO和O3强化甲烷点火的化学动力学过程。 研究表明: 介质阻挡放电等离子体激励空气主要产生N2和O2的若干激发态粒子, 并最终转化成存活时间较长的活性粒子NOx和O3, 等离子体对甲烷点火过程的影响可以简化成活性粒子NOx和O3对甲烷点火过程的影响; CH3的氧化速率决定了甲烷点火过程的快慢, 在自点火过程中CH3的氧化路径是反应式R155和R156, 初始温度较低时R155和R156的反应速率慢, 所以甲烷的点火延迟时间长; NO缩短点火延迟时间是由于CH3的氧化路径由自点火过程中的反应式R155和R156改为反应式R327 CH3O2+NO=CH3O+NO2和R328 CH3+NO2=CH3O+NO; O3强化甲烷点火过程同样是由于O3改变CH3的氧化路径, 从化学动力学上缩短点火延迟时间。

To reveal the mechanism of plasma (assisted the ignition process of methane/air further, schematic of dielectric barrier discharge plasma system with atmospheric air was designed and set up, the emission spectrum of dielectric barrier discharge plasma with atmospheric air was measured, and the active particles produced by the interaction of dielectric barrier discharge plasma with atmospheric air were analyzed with the spectrum technology, the ignition model and calculation methods of sensitivity analysis and reaction path analysis were given, effects of NO and O3 on the ignition delay time were simulated, and the chemical kinetics mechanism of NO andO3 assisted ignition was revealed via sensitivity analysis and reaction path analysis. The results show that main excited particles of N2 and O3 are generated via effect of plasma on the atmospheric air, which are converted into active particles of NOx and O3 in the end, the life of which are longer than any other active particles, effects of plasma on the ignition is simplified as effects of NOx and O3 on the ignition; NO and O3 could reduce the ignition delay time significantly, but the amplitude decrease with increase of the initial temperature, this is because the rate of ignition is decided by the oxidation rate of CH3, the oxidized pathway of CH3 is R155 and R156 for auto-ignition and their rates are slower when temperature is low, so the ignition delay time of methane/air is longer; NO could reduce the ignition delay time significantly because of the oxidized pathway of CH3 is changed to R327 CH3O2+NO=CH3O+NO2, R328 CH3+NO2=CH3O+NO for NOx(assisted ignition process from R155 and R156 for auto-ignition; and the chemical kinetic effect is the dominating factor of O3 on the ignition and which change the reaction path.