激发态粒子是化学反应过程的天然示踪剂, 当前激发态粒子研究主要都是在一维简单火焰下进行。 为了考察复杂情况下激发态分布对化学反应热的定量表征规律, 进行了甲烷/空气同轴射流扩散火焰的试验, 开展了甲烷/空气详细燃烧机理与激发态燃烧机理的同轴射流预混火焰和扩散火焰的数值模拟, 分析了OH*和CH*的分布特性, 研究了激发态对反应热的表征关系。 结果表明: 通过试验ICCD相机和相应滤光片获取的OH*和CH*的化学发光图像和数值模拟中OH*和CH*摩尔分数分布的模拟结果吻合, OH*分布主要分为三个燃烧区域, CH*分布主要为两个燃烧区域。 扩散火焰中OH*和CH*分布呈现单峰, 反应热呈现双峰现象, 反应热与激发态变化趋势相似, 达到第一峰值后激发态逐渐减小为零, 而反应热达到第一峰值后先降低再缓慢上升到第二峰值, 最后减小至零。 扩散火焰中沿轴向方向, 当C2H+O=CH*+CO(R12)反应速率达到峰值时, 反应热达到第一波峰; H+O+M=OH*+M(R2)反应速率达到峰值时, 反应热达到第二波峰。 预混火焰中随着局部当量比的增加, OH*和CH*的摩尔分数明显增大, 分布区域更广; 反应热和激发态粒子OH*和CH*的分布趋势一样, 在激发态粒子OH*和CH*质量分数增大时, 反应热也增大, 当激发态粒子OH*和CH*的质量分数达到峰值的时候, 反应热也达到峰值; 沿轴向方向, OH*和CH*的四个生成反应速率的峰值都在同一位置, 反应热也达到最大值, CH+O2=OH*+CO(R1)和C2H+O=CH*+CO(R12)反应速率相比H+O+M=OH*+M(R2)和C2H+O2=CH*+CO2(R11)反应速率更快。

Excited particle is a natural tracer of the chemical reaction process, but the research on the excited particle is mainly carried out under simple one-dimensional flame. In order to investigate the distributions excited state under complex conditions of chemical reaction heat quantitative characterization of rule, the methane/air coaxial jet diffusion flame test has carried out detailed ground state and excited of methane/air premixed flame burning mechanism of coaxial jet diffusion flamen and numerical simulation, analyzes the distribution characteristics of OH* and CH*, the excited state is studied on the relationship of the heat of reaction. The results showed that the chemiluminescence diagram of OH* and CH* obtained by ICCD camera and corresponding filter and the simulated results of the mole fraction distribution of OH* and CH* in the numerical were consistent. The OH* distribution was mainly divided into three combustion regions, and the CH* distribution was mainly divided into two combustion regions. The distribution of OH* and CH* in the diffusion flame presents a single peak, and the reaction heat presents a bimodal phenomenon. The changing trend of the reaction heat is similar to that of the excited state. After reaching the first peak, the exciter state gradually decreases to zero, while the reaction heat first decreases and then slowly increases to the second peak, and finally reduces to zero. In the diffusion flame, when the mass fraction of OH* and CH* in the radial direction reaches the peak, the heat of reaction also reaches the first peak. In the axial direction when the reaction rate of C2H+O=CH*+CO(R12) reaches the peak, the heat of reaction reaches the second peak. In premixed flames, with the increase of local equivalent ratio, the mass fraction of OH* and CH* increases obviously, and the distribution area is wide. When the mass fraction of OH* and CH* in the radial direction reaches the peak, the heat of reaction also reaches the peak. In the axial direction, the peaks of the four reactions rates of OH* and CH* are all in the same position, and the heat of reaction also reaches the maximum. The reaction rates of CH+O2=OH*+CO(R1) and C2H+O=CH*+CO(R12) are faster than that of H+O+M=OH*+M(R2) and C2H+O2=CH*+CO2(R11).