大型水轮发电机组横向振动的有限元分析

Finite Element Analyses on Transverse Vibration in Large Hydro-electric Generating Set

建立了考虑各种影响因素的大型水轮发电机组自振特性和动力响应计算模型。基于有限单元法,对机组临界转速和动力响应的计算公式进行了推导,编制了与大型软件相接口的程序,并对工程实例进行了计算和分析。讨论了陀螺效应、磁拉力、刚度及阻尼等因素对机组临界转速和动力响应的影响及影响程度,计算结果表明:陀螺效应对机组临界转速影响显著,而对机组的动力响应影响不大;而磁拉力对大型机组的自振特性影响不明显,却是影响机组动力位移的主要载荷;轴承刚度对机组的自振特性和动力响应均有显著的影响。计算模型和计算结果较为合理,为大型水轮发电机组的振动设计和减振研究提供了理论支持。

A self-oscillation characteristics model and a dynamic response model of large hydro-electric genarating set considering all kinds of affecting factors are established. Based on finite element method, the calculating formulas of the critical speed and the dynamic response are developed, the programs that fit to the large software are compiled, and an engineering example is calculated and analysed. The influence and influence degree of various factors such as gyroscopic effect, electric-magnetic forces, stiffness and damp to vibration properties are discussed. The results indicate： the gyroscopic effect and stiffness have obvious effect on critical speed, the electric -magnetic forces cause little effect to self-oscillation characteristics and these forces are main loads for dynamic displacement. The calculation model and the calculated results are rational , and afford some theory supporting for the vibration design and the research of vibration reduction of large hydro-electric generating set.