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 \(4.45 \times 10^4\). 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 4 \(\upmu\)m, 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 SST k–\(\omega\) 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.

具有有限边缘设置的Mach-Zehnder干涉仪适用于由轴对称会聚喷嘴发出的含冲击的微型射流，出口处的内径为1.0 mm。在喷嘴压力比为3.0的条件下进行实验，以产生略微膨胀不足的声速射流，根据喷嘴出口处的直径和流动特性，雷诺数为\（4.45 \乘以10 ^ 4 \）。射流密度场的重建是在假设轴对称流动的情况下使用Abel反演方法以及用于干涉图相移分析的傅里叶变换方法进行的。包含冲击的微射流的三维密度场可以以4 \（\ upmu \）的空间分辨率捕获m，并且在包括射流中心线的横截面的密度等高线图中显示了射流羽内部的近场冲击结构。另外，用各种技术示出了微射流的密度场，包括诸如垂直刀边缘的纹影，水平刀边缘的纹影，明场纹影和阴影照相法的表示。除实验外，雷诺兹用SST k – \（\ omega \）对Navier–Stokes（RANS）进行平均模拟进行湍流模型以对微射流建模，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与先前的Mach-Zehnder干涉仪，背景取向的schlieren以及RANS模拟进行了定量比较。