Abstract The variation of blade axial force of pump-turbine, which may cause instability on impeller shaft system, can be influenced by cavitation. However, the mechanism of this phenomenon is still not clarified. In this study, numerical simulation and experimental research are combined to investigate the influence of leading-edge cavitation on impeller blade axial force in the pump mode of reversible pump-turbine. From no cavitation to critical cavitation, the axial force increases first and then decreases rapidly. The largest increase is 5% and the largest decrease is 13%. Under different flow conditions, the cavitation pattern of blade leading-edge changes differently. With the increase of flow rate, flow separation and pressure drop gradually move from suction side to pressure side. The change of blade axial force caused by the change of blade loading is essentially related to the cavitation occurring on the pressure surface or suction surface. The variation of axial force with cavitation development is similar but the mechanism is different under different conditions. This study reveals the effect of cavitation on blade axial force and its mechanism. The research results can provide reference for improving the operation stability of pump turbine unit.

中文翻译：

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可逆泵-汽轮机泵模式前缘空化对叶轮叶片轴向力的影响

摘要 水泵-涡轮叶片轴向力的变化会引起叶轮轴系不稳定，气蚀会影响其变化。然而，这一现象的机制仍不清楚。本研究将数值模拟和实验研究相结合，研究了可逆泵-涡轮泵模式下前缘空化对叶轮叶片轴向力的影响。从无气穴到临界气穴，轴向力先增大后迅速减小。涨幅最大为5%，跌幅最大为13%。在不同的流动条件下，叶片前缘的空化形式不同。随着流量的增加，流动分离和压降逐渐从吸入侧向压力侧移动。叶片载荷变化引起的叶片轴向力的变化，本质上与压力面或吸力面发生的空化有关。轴向力随空化发展的变化相似，但在不同条件下其机理不同。本研究揭示了空化对叶片轴向力的影响及其机理。研究结果可为提高水泵汽轮机组运行稳定性提供参考。