水流激励下水轮发电机组轴系的振动衰减特性

Vibration Attenuation Characteristics of Shaft System of Hydro-Generator Units under Hydraulic Excitation

振动衰减特性对水轮发电机组轴系的动力学行为有较大影响,为了准确描述水轮发电机组轴系在水流激励下的振动特性,对轴系的振动衰减特性进行研究是十分必要的。首先,在分析水流激励振动特性的基础上,提出基于PSO-VMD的水流激励特征信号提取方法;然后,应用波有限元法建立未包含导轴承和包含导轴承两种情形下的轴单元振动传递模型,在此基础上应用波有限元法构建水轮发电机组轴系的振动传递方程;再根据所构建的轴系振动传递方程确定轴系振动衰减系数的计算方法;最后,通过实例对轴系的振动衰减特性进行分析。研究结果表明,本文所提出的水轮发电机组轴系的振动传递模型及振动衰减系数计算方法是可行、有效的,从而为进一步深入研究振动衰减特性对水轮发电机组轴系动力学行为的影响提供了一定的理论基础。

The vibration attenuation characteristics have a great influence on the dynamic behavior of the shaft system of hydro-generator units.In order to accurately describe the vibration characteristics of the shaft system of hydro-generator units under hydraulic excitation,this paper deems it necessary to investigate the vibration attenuation characteristics of the shaft system.Firstly,a method of extracting hydraulic excitation feature based on PSO-VMD is proposed to analyze the vibration characteristics of hydraulic excitation.Then,the vibration trans⁃mission models with no bearing shaft unit and the vibration transmission model with no bearing shaft unit are established by wave finite ele⁃ment method.According to the models,the vibration transmission equation of the shaft system of the hydro-generator units is constructed by wave finite element method.And according to the constructed vibration transmission equations of the shaft system,the calculation method of the vibration attenuation coefficient of the shaft system is determined.Finally,the vibration attenuation characteristics of the shaft system are analyzed by an example.The research findings show that the vibration transmission model and vibration attenuation coefficient calculation method of shaft system of hydro-generator units proposed in this paper are feasible and effective,which provides a certain theoretical basis for further in-depth research on the influence of vibration attenuation characteristics on the dynamic behavior of shaft system of hydro-gener⁃ator units.