摘要
针对稀释气体影响离子电流前锋区特征峰的研究比较缺乏,以甲烷/空气/稀释气体为对象,通过在定容燃烧弹内布置离子电流测量电极,获得了稀释气种类N2/CO2/Ar和0%、5%、10%、15%几种不同稀释比条件下离子电流的特征峰值,结合CHEMKIN化学反应动力学数值模拟结果,分析了主导离子电流前锋区信号生成的带电组分的数密度、敏感性系数及其生成路径。试验结果表明:相同的稀释比下,CO2稀释对离子电流信号的抑制作用最大;在不同的稀释气体种类下,离子电流前锋区峰值均在过量空气系数λ为0.95时达到最大。数值计算结果表明,对离子电流前锋区信号贡献最大的组分是H3O+和电子e,链分支反应R38、链终止反应R52和离子化初始反应R326对这两种组分浓度的影响较大。在过量空气系数λ为0.95时,O和CH数密度都较大且反应区温度最高,导致化学离子化程度最大,离子电流值前锋区峰值也达到最大值。该结论为研究稀释气体对燃料燃烧的离子电流信号影响和火焰锋面电学特性提供了一定的机理支撑。
To explore the influence of dilution gases on the characteristic peaks of the flame front ion current,methane-air-dilution gases were selected as the objects,and the characteristic peak values of ion current under dilution gases(N2/Ar/CO2) and different dilution ratios (0%,5%,10% and 15%) were obtained by arranging electrodes in the constant volume combustion bomb.The number densities,sensitivity coefficients and generation paths of the dominant charged species affecting flame front ion current signals were analyzed by CHEMKIN chemical reaction numerical simulation.The experimental results show that there is the greatest inhibitory effect on ion current signal under the condition of CO2 dilution.The flame front ion current peak reaches its maximum values when excess air coefficient λ is equal to 0.95 under the condition of different dilution gases.The numerical results indicate that the species which contribute most to the flame front ion current signal are H3O^+ and electron.The chain branching reaction R38,the chain termination reaction R52 and the ionization initial reaction R326 have greater influences on the concentration of the two species.When λ is equal to 0.95,the number densities of O and CH radicals and the reaction zone temperature are the highest,resulting in the largest degree of chemical ionization,and the flame front ion current peak value also reaches its maximum.The conclusions of this paper provide a support for the study of the effects of dilution gas on the ion current signal in fuel combustion and the electrical characteristics of the flame front.
作者
贾伟东
何子奇
杨猛
魏旭星
邓宇
高忠权
JIA Weidong;HE Ziqi;YANG Meng;WEI Xuxing;DENG Yu;GAO Zhongquan(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2019年第1期142-149,共8页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(51306143)
中央高校基本科研业务费专项资金资助项目(xjj2013001)
关键词
定容燃烧弹
离子电流
离子反应机理
稀释气体
constant volume combustion bombs
ion current
ion reaction mechanism
dilution gas
