预混甲烷/空气激光等离子体点火火焰传播与发展过程研究

Study on the Flame Propagation of the Laser Induced Plasma Ignition of the Premixed Methane/Air Mixtures

基于平面火焰燃烧器设计并搭建了层流甲烷/空气预混燃气激光等离子体点火系统,研究了甲烷/空气预混燃气激光等离子体点火火焰传播与发展过程,发现将激光聚焦在层流火焰与扩散火焰交界面时点火成功率更高。通过大量重复性实验,获得了不同点火位置、当量比、入射激光能量下激光等离子体点火的成功率,发现贫燃、高激光能量更利于稳定燃烧火焰的形成。利用高速摄影技术获得了不同点火条件下火焰前沿位置随时间的变化规律,对火焰吹熄现象进行了研究,发现提高预混燃气当量比、增大入射激光能量能够降低火焰吹熄概率。

Design and construct a laser induced plasma ignition system of the premixed methane/air mixtures based on a flat-flamed burner.The flame propagation of the laser induced plasma ignition of the premixed methane/air mixtures is investigated. The steady-state flame is observed and the results show that the rate of the successful ignition will be higher when focusing lasers at the interface between the laminar flame and the diffusion flame. Through the rate of the successful ignition gained from a large number of repetitive experiments, it is found that a lean-burn condition and a high laser energy will be more conducive to the formation of a steady flame. Researches on the blow out of the flame under different ignition conditions is carried out by analyzing the properties of the temporal evolution of the flame front gained from the CCD camera, and results show that the increase of the laser energy and the equivalence ratio will result in a lower ratio of the blow out of the flame.