This paper studies the unsteady three-dimensional cavitating turbulent flow in a jet pump. Specifically, thefocus is on the unstable limited operation stage, and both the computational and experimental methods are used. In the experiments, the distribution of the wall pressure, as well as the evolution of cavitation over time, are obtained for a jet pump. Computation is carried out using the large eddy simulation, combined with a mass transfer cavitation model. The numerical results are compared with the experimental results, including the fundamental performances (the pressure ratio h and the efficiency η), as well as the wall pressure distribution. Both the experimental and computational results indicate that the evolution of the cavitation over time in a jet pump is a quasi-periodic process during the unstable limited operation stage. The annular vortex cavitation inception, development and collapse predicted by the large eddy simulation agree fairly well with the experimental observations. Furthermore, the relationship between the cavitation and the vortex structure is discussed based on the numerical results, and it is shown that the development of the vortex structures in the jet pump is closely related to the evolution of the cavitation. The cavitation-vortex interaction is thoroughly analyzed based on the vorticity transport equation. This analysis reveals that the cavitation in a jet pump dramatically influences the distribution and the production of the vorticity. The process of the annular cavitation inception, development, and collapse involves a significant increase of the vorticity.

中文翻译：

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喷射泵中瞬态空化涡流的大涡模拟，特别强调不稳定的有限运行阶段

本文研究了射流泵中的非定常三维空化湍流。具体而言，重点是在不稳定的受限操作阶段，并且使用了计算和实验方法。在实验中，对于喷射泵，获得了壁压力的分布以及空化随时间的变化。计算是使用大型涡流模拟结合传质空化模型进行的。将数值结果与实验结果进行比较，包括基本性能（压力比h和效率η）。）以及壁面压力分布。实验和计算结果均表明，在不稳定的有限运行阶段，喷射泵中的气穴现象是随时间变化的。大涡模拟预测的环形涡流空化开始，发展和坍塌与实验观测结果吻合得很好。此外，基于数值结果讨论了空化与涡旋结构之间的关系，结果表明，射流泵中涡旋结构的发展与空化的发展密切相关。基于涡度输运方程对空化-涡旋相互作用进行了全面分析。该分析表明，喷射泵中的气穴现象会极大地影响涡度的分布和产生。环形空化开始，发展和崩溃的过程涉及涡度的显着增加。