摘要
介质阻挡放电(DBD)辅助燃烧是等离子体技术领域发展起来的新的应用途径.本文利用CCD相机及光谱仪记录并分析甲烷-空气旋流扩散燃烧火焰形态及特征光谱,研究了等离子体激励的助燃、稳燃机理,分析了不同激励方式对等离子激励效果的影响。实验结果表明,等离子体激励放电会产生大量的自由基及活性基团,如CH,OH,O^+,O原子的各激发态能级及N_2第一正带系等谱线,其中重点分析了加电前后及不同激励方式下O原子(3s^3S^0→3p^5P,λ=777.5 nm)及氮气第一正带系B^3Π_g→A^3∑_u^+粒子(振动带波长为λ=891.2 nm)发射光谱变化,由于氮原子与氧原子均为加速燃烧的重要活性粒子,这些基团的产生使得甲烷更容易发生一系列链式氧化反应。定常激励产生的活性粒子浓度大于未经过等离子体激励及非定常激励下所产生的活性粒子浓度;经过等离子体激励后火焰根部更靠近燃烧器喷嘴底部,说明等离子体激励产生的活性粒子加速了链式反应的进行,缩短了点火迟滞时间.
Ignition and stable combustion pulsed by the dielectric barrier discharge （DBD） is a new way in the field of applying of plasma. In this paper, CCD camera and spectrograph were used to record methane - air mixture combustion flame and obtain the characteristic spectrum. The paper has studied the mechanism of the combustion pulsed by plasma. The results show that the discharge plasma will produce a number of free radicals such as CH, OH, O atoms in the excited level and the N2 first positive band system and other lines. The experiment focuses on the differences on the emission spectrum of incentives O atoms （3s^3s^0 - 3p^5P,λ=777.5nm） and the first brand of the nitrogen B^3Пg-A3∑u^＋（A = 891.2 nm）, which is responsible for the acceleration of the reactions, between when and after the plasma excited. Besides, the active particle exited by the steady mode is greater than that generated by the unsteady mode, which provides evidence that the steady mode could produce more active radicals. At the same time, the root of the flame actuated by the plasma turns to be closer to the bottom of the burner nozzle, which provides additional evidence for that the active particles generated by the plasma has shorten the ignition lag time.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2014年第2期396-400,共5页
Journal of Engineering Thermophysics
基金
国家自然科学基金项目(No.51076150)
国家国际科技合作专项对R项目(No.2013DFR61080)
