氢氧预混气中等离子体放电的影响因素

Influential Factors on Plasma Discharge in Mixtures of Hydrogen and Oxygen

为研究交流激励介质阻挡放电等离子体活性粒子对氢氧预混气体起爆过程的影响,仿真模拟了不同工作条件下氢氧预混气体中的等离子体放电过程,研究了混合气当量比、等离子体激励电压、频率以及电极间隙对活性粒子的影响。结果表明,当量比为4/3时电离度最高,不过当量比对O、H原子数密度的影响受到气体压力的耦合影响;电离度随着激励电压的增大而快速增大,且激励频率较低为好。电极间隙较小时出现2次放电,随着电极间隙增大,第1次放电的强度、范围逐渐增大,而第2次放电则逐渐消失,恰好仅出现1次放电时为最佳放电间隙。建议采用大直径或宽度的进气道、燃烧室,同时采用高电压进行激励。

In order to study the effect of active species which is produced by AC driving dielectric barrier discharge on the detonation process, we simulated the discharge processes in mixtures of hydrogen and oxygen for different work conditions. Moreover, we analyzed the equivalence ratio, voltage and frequency of power source, and gap between two electrodes. The results show the ionization degree reaches the highest when the equivalence ratio is 4/3;however, it should be noted that the effect of equivalence ratio on the density of atom O and H couples is affected by the gas pressure.The ionization degree increases rapidly with applied voltage, and the excitation frequency should be low. When the gap width is little, two times of discharge appear, and the plasma intensity and extent of first discharge will increase but the second discharge will disappear eventually as the gap width increases. The gap width is the best when just only one discharge occurs. It is suggested that a inlet and combustor of large diameter or width should be applied while a plasma actuator is driven by high applied voltage.