介质阻挡放电中氧原子的数值模拟

Numerical Simulation of Oxygen Radicals in Dielectric Barrier Discharge Plasma

由于介质阻挡放电具有许多独特的性质,已被广泛地应用于等离子体化学、环境工程及材料表面处理等诸多领域。为了对其进行更好的研究与应用,笔者根据介质阻挡放电中的不同能量传递过程,建立了一个包括电子碰撞激发、离解、电离,吸附和解吸,复合以及中性粒子参与的反应等过程的N2-O2介质阻挡放电化学反应动力学模型,并通过求解Boltzmann方程,得到电子能量分布函数,进而通过计算获得了电子—分子碰撞的反应速率系数。代入速率方程,获得了系统中各组分粒子数浓度随时间的变化规律。结果表明:O、O3以及N2和O2分子激发态的粒子数浓度随时间先增加后减小,最后趋于一定值;O原子粒子数浓度受N2激发态分子的影响较大;O原子粒子数浓度随O2体积分数的降低而增加。

A chemical kinetic model of dielectric barrier discharge in N2 and O2 mixtures was established according to different energy transfer processes,which includes the processes of electron impact excitation,dissociation,ionization,electron attachment and detachment,recombination,and neutral molecule involved reaction.The electron energy distribution function was obtained by solving the Boltzmann equation,and then reaction rate constant of electron-molecule collision was calculated by the electron energy distribution function.Substituting the reaction rate constant into the equation,the calculation results show that the particle density of O,O3,N2 excitation states and O2 excitation states increase first and then decrease,finally approaching a constant.The density of O atoms is affected by N2 excitation states,and increases when O2 volume fraction decreases.