超声速火焰的3DLIF可视化技术研究

Study on visualization of supersonic flame using Three Dimensional Laser–Induced Fluorescence(3DLIF)

为满足超燃冲压发动机燃烧诊断尤其是燃烧空间结构可视化的迫切需求,亟需实现超声速火焰三维测量。三维激光诱导荧光(3DLIF)技术作为一种立体测量技术具有超声速火焰三维测量的潜力。利用该技术的特点与优势,设计了基于扫描振镜的多平面3DLIF成像系统,在超声速同轴射流燃烧试验装置上实现了超声速火焰的多平面3DLIF空间结构可视化。为了实现大尺寸成像,提出了一种扩大扫描范围的片光整形方案,利用该方案获得了空间尺度50 mm×85 mm×20 mm、时间尺度5 ms的超声速火焰平均三维图像,对3DLIF技术用于超燃冲压发动机试验台架燃烧空间结构可视化进行了可行性分析,基于时均三维图像讨论了喷口火焰速度对火焰结构形状的影响。

In view of the urgent need of scramjet combustion diagnosis, especially the visualization of flame space structure, it needs to realize three– dimensional measurement of the supersonic flames. The Three Dimensional Laser–Induced Fluorescence(3DLIF) technology can realize the visualization of the flame combustion space. For the supersonic coaxial jet combustion,a scanning galvanometer multi– plane 3DLIF experimental device was built, and a laser sheet shaping scheme with expanded scanning range was proposed, which realizes the multi– plane3DLIF visualization of the supersonic flames. The interpolation algorithm was used to reconstruct the three–dimensional average image of supersonic flame with a spatial scale of 50 mm×85 mm×20 mm and a time scale of 5 ms, which verifies the feasibility of using the 3DLIF technology to visualize the combustion space structure of the scramjet test bench. The effect of the flame speed on the flame structure shape using the three–dimensional images is discussed.