A series of turbulent premixed methane/air jet flames are studied using simultaneous planar laser diagnostic imaging of OH/CH/temperature and CH/OH/CH₂O. The Karlovitz number of the flames ranges from 25 to 1500, and the turbulence intensity ranges from 16 to 200. These flames can be classified as highly turbulent flames in the thin reactions zone (TRZ) regime and distributed reaction zone (DRZ) regime. The aims of this study are to investigate the structural change of the preheat zone and the reaction zone as the Karlovitz number and turbulent intensity increase, to study the impact of the structural change of the flame on the propagation speed of the flame, and to evaluate the turbulent burning velocity computed in different layers in the preheat zone and reaction zone. It is found that for all investigated flames the preheat zone characterized with planar laser-induced fluorescence (PLIF) of CH₂O is broadened by turbulent eddies. The thickness of the preheat zone increases with the turbulent intensity and it can be on the order of the turbulent integral length at high Karlovitz numbers. The reaction zone characterized using the overlapping layer of OH and CH₂O PLIF signals is not significantly broadened by turbulence eddies; however, the CH PLIF layer is found to be broadened significantly by turbulence. The turbulent burning velocity is shown to monotonically increase with turbulent intensity and Karlovitz number. The increase in turbulent burning velocity is mainly due to the enhanced turbulent heat and mass transfer in various layers of the flame, while the contribution of flame front wrinkling to the turbulent burning velocity is rather minor.

使用OH / CH /温度和CH / OH / CH _2的同时平面激光诊断成像研究了一系列湍流的甲烷/空气混合预混火焰O.火焰的卡洛维兹数在25到1500之间，湍流强度在16到200之间。这些火焰在稀薄反应区（TRZ）和分布式反应区（DRZ）中可以归类为高湍流火焰。 。这项研究的目的是研究随着卡洛维兹数和湍流强度增加预热区和反应区的结构变化，研究火焰的结构变化对火焰传播速度的影响，并评估在预热区和反应区的不同层中计算出的湍流燃烧速度。发现对于所有研究的火焰，预热区的特征在于CH _2的平面激光诱导荧光（PLIF）O因湍流涡旋而扩大。预热区的厚度随着湍流强度的增加而增加，并且在高卡洛维兹数下可以达到湍流积分长度的数量级。使用OH和CH ₂ O PLIF信号的重叠层表征的反应区不会被湍流涡旋显着加宽；然而，发现CH PLIF层由于湍流而显着变宽。湍流燃烧速度显示出随着湍流强度和卡洛维兹数单调增加。湍流燃烧速度的增加主要归因于火焰各层中湍流热和质量传递的增强，而火焰前沿起皱对湍流燃烧速度的贡献却很小。