平面激光诱导荧光技术在超声速燃烧火焰结构可视化中的应用

平面激光诱导荧光（PLIF）技术能够高时空分辨成像火焰结构并用于研究超声速燃烧机理。利用OH-PLIF与CH-PLIF技术研究了超声速燃烧的火焰结构。其中，利用OH-PLIF技术对燃烧室中3个展向截面与2个流向截面的凹腔稳定火焰反应区结构进行成像，利用CH-PLIF技术观测凹腔火焰放热区结构。实验结果表明:全局当量比较低时燃烧主要发生在凹腔中，OH沿中轴线对称分布；高当量比时火焰位置更高，OH主要沿燃烧室两侧壁面分布；CH所存在的超声速燃烧放热区呈现高度褶皱和破碎结构，放热区分布在比反应区更窄的区域。

Visualization of flame structure in supersonic combustion by Planar Laser Induced Fluorescence technique

Planar Laser Induced Fluorescence (PLIF) can be used to visualize the flame structure with high temporal and spatial resolution and investigate the mechanism of supersonic combustion. In this paper, OH-PLIF and CH-PLIF techniques were used to study the flame structure in supersonic combustion. The cavity-stabilized reaction zone structure of the three streamwise sections and two spanwise sections in a supersonic combustor was obtained by using the OH-PLIF technique. The experimental results show that the combustion occurs in the inner cavity and the OH radicals are distributed symmetrically along the central axis at a low global equivalence ratio. The OH radicals are primarily distributed at two-side-wall of the combustor and the location of the flame is higher than that of the cavity at a high equivalence ratio. The heat-release structure of the cavity-stabilized flame was observed by the CH-PLIF technique. It is found that the heat-release zone is highly wrinkled and distorted in the supersonic combustion and it is distributed in a narrower region than the reaction zone.