一种水力机械压力脉动的分频模态提取方法及应用  

Method for extracting frequency-domain modal parameters of pressure pulsations in hydraulic machines and its application

作　　者：周济宸 牛翔宇 林贵海 刘鑫 ZHOU Jichen;NIU Xiangyu;LIN Guihai;LIU Xin(Department of Computer Science and Technology,Shanghai University,Shanghai 200444,China;State Grid Xinyuan Group Co.,Ltd,Beijing 100052,China;Shuikou Power Generation Co.,Ltd,Fuzhou 350004,China;China Huaneng Group Clean Energy Technology Research Institute Co.,Ltd,Beijing 102209,China)

机构地区：[1]上海大学计算机科学与技术系,上海200444 [2]国网新源集团有限公司,北京100052 [3]福建水口发电集团有限公司,福州350004 [4]中国华能集团清洁能源技术研究院有限公司,北京102209

出　　处：《水力发电学报》2023年第8期89-97,共9页Journal of Hydroelectric Engineering

摘　　要：水力机械在偏离最优工况条件下,水压脉动可能包含多种频率成分,对流场时域分析时,小幅值次主频率成分的非定常演变特征常被主频成分的时域演变所掩盖。本文借鉴结构动力学中模态参数提取方法,采用基于自然激励技术,由复响应函数获得不同频率下的模态参数,并编程计算了水力机械内的典型三维流场水力激励分频模态,分析了混流式水轮机小流量下的计算结果,刻画了尾水管涡带的低阶旋转模态,揭示了尾水管内高阶频率成分的产生与无叶区内旋转扰动源的关联关系。同时,还对动静干涉等原因导致的转轮上的激振模态进行分析,模态结果与理论预测一致。本文提出的分频模态分析方法有助于揭示不同频率压力脉动产生的根源、传播途径等信息。When operating at the off-design condition,the pressure pulsations within a hydraulic machine may contain multiple frequency components.In time domain analysis of the flow,the unsteady characteristics of the lower-amplitude subharmonic frequency components are often overshadowed by the time-domain evolution of the dominant frequency component.Based on the ideas of the modal parameter extraction methods in structural dynamics,this paper describes a new method for extracting frequencydomain modal information from the flow field,using the natural excitation technique.Modal parameters at different frequencies are obtained through complex response functions,and relevant codes are developed to apply this method to analysis of the unsteady flow fields in a mixed-flow water turbine.We examine the simulation results of the turbine operating at low flow rates,characterize the vibration modes of draft tube vortices,and reveal the relationship between the generation of higher-order frequency components in the draft tube and the rotational perturbation source in the bladeless section.Meanwhile,we give an analysis of the impeller excitation modes caused by rotor-stator interference and other factors.The modal results has been verified with theoretical predictions.Thus,our frequency-domain modal analysis method helps reveal information such as the sources and propagation of pressure pulsations at different frequencies.

关 键 词：水力机械 水压脉动 模态 复响应函数 混流式水轮机 

分 类 号：TV136[水利工程—水力学及河流动力学]