基于CFD的水电站厂房水力振源特性及精确施加方法研究

发布时间：2018-06-27 18:04

本文选题：水力振源 + 水电站厂房　；参考：《西安理工大学》2017年硕士论文

【摘要】：水力振源是引起厂房结构振动的最重要因素,也是最难以描述和模拟的因素。由于水轮机流道内部流动的复杂性,单一构件内的流动特性不能完整体现整个流道的流动规律和本质。论文综合分析了目前对于水电站厂房水力振源特性及施加方法研究的现状,在基于CFD的水力振源特性研究基础上,研究了水轮机流道,尤其是壁面处的水力振源规律,提出了水力振源的精确模拟施加方法。本文建立了全流道非定常湍流数值模型,基于SST双方程湍流模型实现了全流道非定常湍流计算,分析了正常运行工况下蜗壳、尾水管壁面的压力脉动分布特征,总结了水力振源幅值、频率及规律。在CFD计算基础上,采用谐响应分析,在正常运行工况下,依据水力振源幅值、频率分布特征,对蜗壳壁面进行了区域划分,提出了五种简化施加方案,厂房动响应数值计算结果表明,将各区域典型代表点的压力脉动幅频数据作为简谐面压力施加于区域面,接近水力振源真实作用情况时,得到的厂房振动响应较传统全流道单一振幅、频率面压力施加方法更大。由于流体计算与厂房结构网格尺度的差异,通过ANSYS二次开发,编制CFD计算压力脉动结果导入厂房结构程序,通过流体域与结构域中蜗壳、尾水管壁面各点坐标位置建立压力脉动时程一一对应规则。利用SFFUN命令实现了流道壁面各节点各时刻均按CFD结果如实模拟的压力脉动实时精确模拟施加方法,并将所得厂房响应情况与以典型点为参考的点而转换施加方法进行对比。结果表明,本文提出的基于CFD的脉动压力精确模拟施加方法考虑了流道各点水力振源的幅值、频率差异的影响,厂房响应更趋于合理。
[Abstract]:The hydraulic vibration source is the most important factor which causes the vibration of the structure of the plant. It is also the most difficult factor to describe and simulate. Due to the complexity of the flow in the turbine runner, the flow characteristics in the single component can not fully reflect the flow law and the essence of the whole flow channel. On the basis of the study on the characteristics of the hydraulic vibration source based on CFD, this paper studies the law of hydraulic vibration source of the hydraulic turbine, especially the wall, and puts forward the accurate simulation method of the hydraulic source. In this paper, a numerical model of the unsteady turbulent flow in the full flow channel is set up. Based on the SST double equation turbulence model, the unsteady flow path is realized. The pressure fluctuation distribution characteristics of the spiral case and the tube wall under normal operating conditions are analyzed. The amplitude, frequency and law of the hydraulic source are summarized. On the basis of the CFD calculation, the harmonic response analysis is used to divide the wall surface of the volute on the basis of the characteristics of the amplitude and frequency distribution of the hydraulic source. Five simplified application schemes are applied. The numerical results of the dynamic response of the workshop show that the vibration response of the typical representative points of the representative points of the region is applied to the region surface as the simple harmonic surface pressure. The vibration response of the workshop is more than the single amplitude of the traditional full channel and the method of applying the frequency surface pressure. The difference between the fluid calculation and the scale of the grid structure of the workshop is made. Through the development of the ANSYS two times, the pressure pulsation result of the CFD calculation is introduced into the structural program of the workshop, and the one-to-one corresponding rules of the pressure pulsation time history are established through the fluid domain and the spiral case in the structure domain and the coordinates of the wall of the tailpipe wall. Each node of the wall surface of the flow channel is realized with the SFFUN command. The real time and accurate simulation of pressure pulsation is simulated on the basis of the CFD results, and the response of the workshop is compared with that of a point with the typical point as a reference point. The results show that the method of accurate simulation of the pulsating pressure based on the CFD is taken into consideration of the amplitude and frequency difference of the hydraulic sources at the various points of the channel. With the influence of the difference, the response of the plant is more reasonable.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV312

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