Application of Rainbow Schlieren Deflectometry for Shock-Containing Supersonic Jets

采用彩虹纹影系统测定了圆柱形喷嘴发出的欠膨胀声波射流中的密度场。结果表明，利用水平和垂直彩虹滤光片可以清晰地观察到射流结构。从纹影图像的阿贝尔反演可以有效地推断出任何射流截面的密度分布。此外，本文还建立了圆柱喷管流动特性的解析模型，并与实验结果进行了比较。此外，采用彩虹纹影偏转法对传统和改进的韭菜去皮喷嘴的射流进行了定性和定量比较。与传统喷嘴相比，改进喷嘴的射流对韭菜脱皮具有较高的脱皮潜力。

A rainbow schlieren system has been employed to determine the density fields in the underexpanded sonic jet from a cylindrical nozzle. As a result, the jet structure can be clearly observed by schlieren pictures with horizontal and vertical rainbow filters. Density profiles at any jet cross-section can be efficiently inferred from the Abel inversion of the schlieren images. Also, an analytical model to predict the flow properties through the cylindrical nozzle is proposed and compared with the present experimental results. Furthermore, conventional and improved nozzles for peeling leeks are used for qualitative and quantitative comparison of jets from their nozzles by the rainbow schlieren deflectometry. It is found that the jet from the improved nozzle has a high removing potential for peeling leeks in comparison with the conventional one.