基于水力振源合理施加的水电机组轴系统振动分析

水力振源诱发机组厂房结构振动,影响机组发电效率,甚至威胁其正常安全运行。合理模拟机组振源是研究预测及解决机组厂房结构振动问题的关键。通过CFD(计算流体动力学)数值模拟,提出一种水轮机转轮叶片表面脉动压力的更为合理的计算和施加方法,并综合考虑电磁和机械振源的耦合作用,对所建立的三维水轮发电机组转子-轴承系统模型进行了振动分析。研究表明:通过CFD能够获得可信的转轮表面处各点脉动压力时程,脉动压力对轴系统振动响应的影响不可忽略,对其合理的模拟和施加是必要的。此外,进行了电磁不平衡拉力与机械不平衡力相位差对轴系振动响应的敏感性分析。研究结论可为水电机组及厂房设计运行及振动预测控制等提供参考。

Vibration analysis of the shaft system based on the reasonable application of hydraulic vibration source

The vibration of hydraulic vibration source causes the vibration of power plant structure, which affect the generator efficiency, and even threaten its normal operation. It is the key to predict and solve the vibration problem of the plant structure. This paper relies on Computational Fluid Dynamics(CFD) numerical simulation to propose a method of applying the reasonable calculation of turbine runner surface pressure fluctuations, and to consider the coupling of electromagnetic and mechanical vibration, and to analyze 3D turbine rotor bearing system model. The results show that the time history of fluctuating pressure at the surface of the runner can be obtained reliably by CFD, and the influence of fluctuating pressure on the vibration response of the axle system cannot be neglected; therefore, it is necessary to legitimately simulate and apply it. In addition, the sensitivity analysis of the phase difference between the electromagnetic unbalance tension and the mechanical unbalance force is given to the vibration response of the shafting. This study provides reference for the design and operation of the hydropower unit and the plant vibration prediction control.