水轮机整机系统动力特性分析的多级模态综合方法

采用多级模态综合技术并利用结构旋转对称的特点，建立包括转动部件和固定部件在内的水轮机整机系统动力特性分析模型。考虑到油膜特性引起的矩阵不对称性是局部的，将实模态分析与复模态分析结合，仅需对极小规模的非对称矩阵解左右复特征值问题。给出的轴—板架系统复特征值结果与整体计算结果吻合，而计算时间大为节省。大型水轮机包括主轴、顶盖、下机架和上机架的整机系统的动力特性算例中，不仅得到了主轴弯曲振动频率，而且得到了固定部件与主轴耦合振动的频率和振型。算例表明了本文模型不仅理论先进，而且能用于工程实际计算。

Multiple-step mode synthesis method for dynamic analysis on whole hydroelectric machine system

A model for dynamic analysis on a whole hydroelectric machine system was studied by multiple step mode synthesis technique, which consists of rotary and fixed components. The rotational symmetry of fixed components was fully utilized for junior synthesis. Considering the locality of coefficient matrices unsymmetry due to oil film characteristic of journal bearings, complex mode analysis was employed together with real mode analysis and complex eigenvalue problems to be finally solved was only limited to a small matrix. Given example on an axle plate frame system shows that the results by multiple step mode synthesis are in good agreement with those by directly on the whole system while the expended CPU time is reduced dramatically. During calculating dynamic characteristics of a real large scale hydraulic generator set, not only the bending vibration frequency and mode shape of the shaft but also the coupling vibration frequency and mode shape of the rotary and fixed components were computed. The success shows the approach is not only superior in theory, but also practical for engineering analysis.