Quantitative Flow Visualization of Slightly Underexpanded Microjets by Mach-Zehnder Interferometers
Quantitative Flow Visualization of Slightly Underexpanded Microjets by Mach-Zehnder Interferometers
复制标题
通过马赫-曾德干涉仪对稍微欠膨胀的微射流进行定量流动可视化
DOI：
10.1007/s10494-020-00211-4
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Yojiro Ishino & Kenji Miki
中科院分区：
文献类型：
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作者：
Sugawara;S.;Nakao;S.;Miyazato;Yojiro Ishino & Kenji Miki
采用有限条纹设置的马赫-曾德尔干涉仪对出口内径为1.0mm的轴对称收敛喷管中的含激波微射流进行了测量。实验在喷嘴压力比为3.0时进行，以产生略微欠膨胀的音速射流，其中雷诺数基于喷嘴出口处的直径和流动特性。射流密度场的重建是在轴对称流动的假设下使用Abel反演方法以及干涉图相移分析的傅里叶变换方法进行的。该方法可获得含激波微喷流的三维密度场，空间分辨率为4 m，在含喷流中心线的截面上的密度等值线图显示了喷流羽流内部近场激波结构。此外，密度场的微射流说明与各种技术，包括表示，如垂直刀口纹影，水平刀口纹影，明场纹影，和阴影。除了实验，雷诺平均Navier-Stokes（RANS）模拟与SSTk湍流模型进行模拟的微射流，并与实验进行定量比较。通过本实验获得的射流中心线密度分布定量地比较从以前的马赫-曾德尔干涉仪，背景定向纹影，以及RANS模拟。
The Mach–Zehnder interferometer with the finite fringe setting is applied for a shock-containing microjet issued from an axisymmetric convergent nozzle with an inner diameter of 1.0 mm at the exit. Experiments are performed at a nozzle pressure ratio of 3.0 to produce a slightly underexpanded sonic jet where the Reynolds number, based upon the diameter and flow properties at the nozzle exit, is. The reconstruction of the jet density field is performed using the Abel inversion method under the assumption of an axisymmetric flow as well as the Fourier transform method for the phase shift analyses of interferograms. The three-dimensional density field of a shock-containing microjet can be captured with a spatial resolution of 4m, and the near-field shock structure inside the jet plume is shown in the density contour plot at the cross-section including the jet centerline. In addition, the density field of the microjet is illustrated with various techniques, including representation such as the vertical-knife-edge schlieren, the horizontal-knife-edge schlieren, the bright-field schlieren, and the shadowgraphy. In addition to experiments, the Reynolds averaged Navier–Stokes (RANS) simulation with the SSTk–turbulence model is carried out to model the microjets, and a quantitative comparison with the experiments is performed. The jet centerline density profile obtained by the present experiment is quantitatively compared with those from the previous Mach–Zehnder interferometer, the background oriented schlieren, as well as the RANS simulation.