羟基分子标记示踪速度测量中的强振动干扰抑制

摘要

In order to suppress the strong vibration disturbance in Hydroxyl Tagging Velocimetry (HTV) in practical experimental environment for an engine,the characteristic of radiation spectrum of tagging laser interacted with different flow fields was analyzed experimentally.In the experiment,two strategies for vibration disturbance suppression were designed by capturing the tagging laser image and moved tagging image simultaneously.For a general flow field,the Rayleigh scattering of the tagging laser was used as reference images,and in a combustion flow field which contained unburned large hydrocarbon fuel like kerosene,CH4,the radiation of the tagging laser induced fuel in the waveband of OH fluorescence spectrum was taken as reference images.The velocity measurement in the flow field of a scramjet engine indicates that the two approaches can suppress the vibration disturbance efficiently.Moreover,the Rayleigh scattering image of the tagging laser is disturbed by wall scattering in the relative pure flow region,making the uncertainty of the base tagging position identification approximate to 0.06 mm.In the follow region with abundant unburned fuels,the latter method can obtain comparatively clear tagging laser images with the uncertainty of base tagging position identification reduced to 0.03 mm,which equals to the uncertainty of the average method.%针对在发动机实验环境中羟基分子标记示踪速度测量技术受到的强振动干扰问题,通过实验研究分析了标记激光与不同流场作用时产生的辐射光谱特性,设计了在实验中同时拍摄标记基准图像和移动图像的振动干扰抑制方法.对于一般流场,在实验中实时拍摄标记激光瑞利散射作为标记基准图像,而对于含有煤油大分子碳氢燃料的流场甚至是CH4燃烧场,用标记激光诱导燃料在OH荧光辐射波段的辐射光作为标记基准图像.在超燃发动机的速度测量应用尝试表明,两种方案均可以达到抑制振动的目的.在相对干净的流场区域,前者得到的标记激光图像会受到壁面散射等干扰,基准位置提取不确定度约为0.06 mm.在流场中未燃燃料含量比较丰富的区域,后者能够得到清晰的标记基准图像,基准位置提取不确定度可以降至0.03 mm,与采用平均方法得到的基准位置提取不确定度相当.