汽轮发电机组弹簧隔振基础模型动力特性试验

Experiment study on dynamic characteristics of spring vibration isolating foundation for large turbine-generator set

摘要:

为了考察汽轮发电机组采用弹簧隔振基础的振动特性,基于模型模态试验方法进行试验研究,根据相似理论设计制作了田湾核电站3、4号机组(2×1 000 MW)汽轮发电机弹簧隔振基础的8∶1缩尺模型,采用激振法对模型的动力特性进行模态分析,得到基础模型的固有频率、振型、阻尼比等自振特性;通过以上测试结果进行强迫响应的振动分析,得到机组运行状态下的基础振动线位移结果．试验结果证明,通过弹簧隔振器的设计,使结构自振频率的分布在工作频率25 Hz附近比较稀疏,半速机采用弹簧基础优势明显;扰力点在启动过程中的最大振动线位移为23.19 μm,在工作转速范围内的最大振动线位移为11.73 μm,隔振效率平均为X向68.4％、Y向83.1％、Z向84.0％,均满足《动力机器基础设计规范》要求．

Abstract:

To investigate the vibration characteristics of spring vibration isolating foundation for turbine-generator set, the modal tests are performed by model modal test method. A model of 8:1 of spring vibration isolating foundation for turbine-generator set for a 2×1 000 MW in Tianwan nuclear power plant units 3 and 4 is built up according to similarity theory, and then the test of dynamic characteristic is carried out by exciter method, and the natural vibration frequencies, mode shapes and damping ratio are acquired. The results of basic vibrating linear displacement under operation condition are obtained based on the vibration analysis of test data. The results show that the distribution of natural frequencies of structure was sparse in the vicinity of the operating frequency of 25 Hz by designing spring vibration isolating foundation. The maximum linear displacement of test point is 23.19 μm during the start-up and 11.73 μm during the operating speed range. Isolation efficiency of foundation are X-direction to 68.4％, Y-direction to 83.1％, Z-direction to 84.0％, which meet the requirements of Chinese specification "Dynamic machine foundation design specifications".