抽水蓄能电站水泵水轮机的动静干涉与振动分析

Analysis on rotor-stator interaction and vibration of pump turbine in pumped storage power station

针对抽水蓄能电站水泵水轮机运行过程中出现的振动问题,从产生共振的条件出发,分析了转轮叶片和活动导叶形成的叶栅组合的动静干涉机理。根据转轮对水力激振模式的动态响应,研究了不同叶栅组合方式对水力激振力的影响。建立流固耦合数学模型,对转轮、活动导叶、顶盖及底环等过流部件的动态特性进行了有限元分析,以7/20的叶栅组合为例,阐述了流体激发结构共振的可能性。为了避免过流部件发生共振以及由此产生的疲劳裂纹或断裂等事故,提出了最佳叶栅组合的选择原则、降低无叶区压力脉动的方法以及提高结构固有频率和降低局部应力集中系数的具体措施。

Mechanism of production of rotor-stator interaction with the cascades match composed of runner blades and wicket gates is analyzed aiming at the problem that there is vibration during operation of pump turbine in pumped storage power station. Influence of different cascades matches on hydraulic excitation force is studied based on dynamic response of runner to hydraulic excitation mode. Finite element analysis on dynamic characteristics of hydraulic turbine components including runner, wicket gate, head cover and bottom ring are carried out by using fluid structure interaction method and corresponding model. The resonance possibility of structure excited by fluid is stated for cascades match 7/20. In order to avoid resonance of hydraulic turbine components and the consequent fatigue crack and fracture accident, selection principles of optimal cascades matches, methods of reducing pressure fluctuation in vaneless space and concrete measures for increasing natural frequencies and reducing factor of stress concentration of structures are proposed.