Fundamental understanding of chemical kinetics pathways involved in ignition and flame propagation in hydrocarbon flames is essential for designing efficient and clean combustion devices for aerospace applications. In this study, spherically propagating methane-air and methane-ethane-air flames inside a constant-volume vessel were characterized using a species-specific, high-speed chemiluminescence diagnostic to reveal the position of the spatially and temporally resolved flame front and the primary combustion zone. The emission recorded by a high-speed camera with an image intensifier was used to investigate the effects of equivalence ratio on the chemiluminescence from electronically excited hydroxyl (OH*) and methylidyne (CH*) radicals. High-speed movies of OH*, CH*, and total broadband signals were recorded. The line-of-sight integrated images were Abel-inverted to obtain the spatially resolved two-dimensional flame structure and the temporal evolution of radical zone thickness. Features such as direct laminar flame-speed determination, flame wrinkling at elevated pressures, and the reaction zones of flames propagating under well-characterized initial turbulent conditions were all well-captured by the high-speed chemiluminescence imaging. In addition to visualizing the flame fronts and subsequent determination of the flame speed, this technique provides the simultaneous information of reactive chemical species that is not available using commonly used schlieren-based imaging methods.

对涉及碳氢化合物火焰中点火和火焰传播的化学动力学途径的基本了解对于设计用于航空航天应用的高效清洁燃烧装置至关重要。在这项研究中，恒定体积容器内的球形传播甲烷-空气和甲烷-乙烷-空气火焰使用特定物种的高速化学发光诊断进行表征，以揭示空间和时间分辨的火焰前沿和初级的位置燃烧区。带有图像增强器的高速相机记录的发射用于研究当量比对电子激发的羟基 (OH*) 和甲基炔 (CH*) 自由基的化学发光的影响。记录了 OH*、CH* 和总宽带信号的高速电影。对视线综合图像进行阿贝尔反演，获得空间分辨的二维火焰结构和自由基区厚度的时间演变。诸如直接层流火焰速度测定、高压下的火焰起皱以及在充分表征的初始湍流条件下传播的火焰反应区等特征都被高速化学发光成像很好地捕获。除了可视化火焰前沿和随后确定火焰速度之外，该技术还提供了使用常用的基于纹影的成像方法无法获得的反应性化学物质的同步信息。诸如直接层流火焰速度测定、高压下的火焰起皱以及在充分表征的初始湍流条件下传播的火焰反应区等特征都被高速化学发光成像很好地捕获。除了可视化火焰前沿和随后确定火焰速度外，该技术还提供了使用常用的基于纹影的成像方法无法获得的反应性化学物质的同步信息。诸如直接层流火焰速度测定、高压下的火焰起皱以及在充分表征的初始湍流条件下传播的火焰反应区等特征都被高速化学发光成像很好地捕获。除了可视化火焰前沿和随后确定火焰速度之外，该技术还提供了使用常用的基于纹影的成像方法无法获得的反应性化学物质的同步信息。