甲烷/空气混合气体放电等离子体动力学机理分析

Analysis on Plasma Kinetic Mechanism of Methane/Air Discharge

为研究甲烷/空气混合气体放电等离子体机理,利用建立耦合组分浓度方程和能量传递方程以及Boltz-mann方程的等离子体动力学模型,分别对不同碰撞类型的电子能量损失比率、等离子体中能量传递过程以及单次放电和重复放电粒子浓度的演化规律进行了分析研究。结果表明:电子能量主要损失于电子与混合气分子的第2类、第3类碰撞过程,与第1类碰撞过程能量损失较小;空气放电的加热能在1 ms时约为输入能的50%,混合气放电的加热能在5.0×10-3ms时达到了输入能,在1 ms时约高出输入能26%,计算得到了空气和混合气温度约为311 K和380 K;单次放电时等离子体没有促进燃料氧化的链锁反应,而重复放电时促进了链锁反应,但其过程不能持续。

For the study of methane/air plasma discharge mechanism,established plasma kinetic model combined with component density equations,energy transfer equations and Boltzmann equations was applied to analyze electronic energy loss rate of different impact types,energy transfer process in the plasma and evolution laws of particle density of single discharge and repetitive discharges.The results show： electronic energy loss mainly exists in the second and third impact types of electronic and mixture gas molecules,and less electronic energy loss in the first type;thermalized energy of air discharge is approximately 50% of its input energy at 1ms,thermalized energy of mixture gas discharge reaches its input energy at about 5.0×10^-3 ms and approximately 26% higher than its input energy at 1ms,plasma temperature of air and mixture discharges were about 311K and 380K respectively;plasma initiates no fuel-oxidant chain reaction in single discharge,and plasma initiates fuel-oxidant chain reaction in repetitive discharges but the chain reaction can＇t sustain for a long time.