Cavitating flow dynamics are investigated in an axisymmetric converging–diverging Venturi nozzle. Computational Fluid Dynamics (CFD) results are compared with those from previous experiments. New analysis performed on the quantitative results from both datasets reveals a coherent trend and shows that the simulations and experiments agree well. The CFD results have confirmed the interpretation of the high-speed images of the Venturi flow, which indicated that there are two vapor shedding mechanisms that exist under different running conditions: re-entrant jet and condensation shock. Moreover, they provide further details of the flow mechanisms that cannot be extracted from the experiments. For the first time with this cavitating Venturi nozzle, the re-entrant jet shedding mechanism is reliably achieved in CFD simulations. The condensation shock shedding mechanism is also confirmed, and details of the process are presented. These CFD results compare well with the experimental shadowgraphs, space–time plots, and time-averaged reconstructed computed tomography slices of vapor fraction.

中文翻译：

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文丘里喷嘴中气穴和蒸汽脱落机制的研究

在轴对称会聚-发散文丘里喷嘴中研究空化流动动力学。计算流体动力学 (CFD) 结果与先前实验的结果进行了比较。对两个数据集的定量结果进行的新分析揭示了一致的趋势，并表明模拟和实验吻合良好。CFD结果证实了文丘里流高速图像的解释，表明在不同运行条件下存在两种蒸汽脱落机制：折返射流和凝结激波。此外，它们提供了无法从实验中提取的流动机制的更多细节。首次使用这种空化文丘里喷嘴，在 CFD 模拟中可靠地实现了重入射流脱落机制。还确认了冷凝冲击脱落机制，并介绍了该过程的细节。这些 CFD 结果与实验阴影图、时空图和蒸汽分数的时间平均重建计算机断层扫描切片进行了很好的比较。