大气压脉冲调制射频氦气放电特性的数值模拟

Numerical Study on the Characteristics of Pulse Modulated Radio-frequency He Discharges at Atmospheric Pressure

采用脉冲调制可以有效优化大气压射频放电行为。为此利用1维流体模型,考虑了氦等离子体放电过程中主要的13个反应及6种粒子,研究了大气压脉冲调制射频氦气放电特性,并分析了调制频率、占空比对放电特性的影响以及输入电压对达到最大电子数密度所需时间的影响。结果表明:脉冲调制之后,固定调制频率时,随着占空比的减小,氦气放电的击穿电压增大;固定输入电压时,最大电子数密度所需时间与剩余电子数密度成反比。利用功率输入时间及最大电子数密度所需时间的关系,合理选择占空比及调制频率可以在满足实际应用的同时,最大地节约功率损耗;固定占空比及调制频率时存在着最优输入电压,使得最大电子数密度所需时间最短。

Using pulse modulation can effectively improve atmospheric radio-frequency discharges. Hence , using aone-dimensional fluid model and taking 13 key reactions and 6 species of pure He discharge into consideration, we inves-tigated the characteristics of pulse modulated radio-frequency He discharge, and discussed the relation between themodulation＇s frequency and duty cycle and the discharge characteristics, as well as the influence of the input voltage onthe time required to reach the maximum electron density. The results show that when the modulation frequency is fixed,the breakdown voltage increases with increasing duty cycle. When the input voltage is fixed, the time required for maxi-mum electron density is inversely proportional to residual electron density. Hence, according to relationship betweenpower-off period and required time for maximum electron density in consideration, a reasonable selection of modulationfrequency and duty cycle can greatly reduce power consumption while satisfying application requirements. Likewise, ifthe duty cycle and modulation frequency are fixed, there is an optimal input voltage which can minimize the required timefor maximum electron density, and a reasonable input voltage helps to improve the discharge characteristics.