The present study provides flow visualization on complex internal flows in a radial diffuser pump under part-load conditions by using the three-dimensional Navier-Stokes code CFX-10 with Detached Eddy Simulation (DES) turbulence model. Particle Image Velocimetry (PIV) measurements have been conducted to validate numerical results. The CFD results show good agreements with experimental ones on both the phase-averaged velocity fields and turbulence field. The detailed flow analysis shows that no separation occurs at 0.75Qdes although a low-velocity zone develops on the rear impeller suction side. Steady flow separations are observed on the impeller suction sides at 0.5Qdes but with different onsets and amounts. When reducing the flow rate to 0.25Qdes, CFD predicts different types of back flows in the impeller region, including steady leading edge separations, rotating vortex in the impeller wake region, and back flow on the impeller pressure side.

中文翻译：

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径向扩散泵部分负载条件下的不稳定流动可视化：通过 PIV 和 CFD

本研究通过使用三维 Navier-Stokes 代码 CFX-10 和分离涡流模拟 (DES) 湍流模型，提供了部分负载条件下径向扩散泵中复杂内部流动的流动可视化。已进行粒子图像测速 (PIV) 测量以验证数值结果。CFD 结果与实验结果在相平均速度场和湍流场上均显示出良好的一致性。详细的流动分析表明，尽管在后叶轮吸入侧形成了低速区，但在 0.75Qdes 处没有发生分离。在叶轮吸入侧以 0.5Qdes 观察到稳态流动分离，但具有不同的起始点和数量。当流量降低到 0.25Qdes 时，CFD 预测叶轮区域不同类型的回流，