拱坝坝身泄洪孔道脉动压力分布规律及其振动特征  

The Distribution and Vibration Mechanism of Pulsating Pressure in the Spillway of Arch Dam

作　　者：龚成勇[1] 谢庚淼 樊新建[1] 许浪 陈超 梁康 GONG Chengyong;XIE Gengmiao;FAN Xinjian;XU Lang;CHEN Chao;LIANG Kang(College of Energy and Power Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Power China Northwest Engineering Corporation Limited,Xi’an 710065,China)

机构地区：[1]兰州理工大学能源与动力工程学院,兰州730050 [2]中国电建集团西北勘测设计研究院有限公司,西安710065

出　　处：《太原理工大学学报》2024年第6期958-970,共13页Journal of Taiyuan University of Technology

基　　金：科技部创新方法专项(2020IM030400);流体与动力机械教育部重点实验室开放基金(LTDL2020-001);教育部高等学校能源动力类教学研究与实践项目(NSJZW2021Y-09)。

摘　　要：【目的】高拱坝坝身泄洪安全研究涉及泄洪孔道设计、结构强度、泄洪过程中的水流压力分布和流态特性等方面。【方法】以某坝高为270 m拱坝为研究对象,利用计算流体力学模拟坝身泄洪孔道流场并分析其脉动压力分布特征,利用流体/结构耦合有限元模拟最不利工况压力脉动与坝体结构振动特征,解析泄流激励下高拱坝坝身振动机理。【结果】研究结果表明,拱坝坝身泄洪孔道内脉动压力变化极为复杂,其中表孔脉动压力最大值为133.25 kPa,最小值为29.48 kPa;中孔脉动压力最大值为5274.99 kPa,最小值为953.24 kPa.拱坝坝身泄洪孔道脉动压力在频域的能量分布均具有低频的特征,主能量分布在0~10 Hz的频率范围内。在泄流激励条件下,拱坝坝身总位移随脉动压力变化呈现一定周期性,且随周期总位移逐渐衰减,总位移值与脉动压力在同周期内先增大后减小,总位移值在1.2 s增大至最大值0.2120 cm,对应泄洪孔道脉动压力增大至极大值;拱坝坝身等效应力和等效应变的变化规律基本一致,1.2 s时等效应力和等效应变极大值分别为1426.60 kPa、7.49×10^(-5),且同周期内脉动压力呈现同样的变化趋势,拱坝坝身等效应力和等效应变与脉动压力变化具有完全的相关性。【Purposes】The study on flood discharge safety of high arch dam involves the design of spillways,the strength of structure,the distribution of flow pressure,and the characteristics of flow pattern during flood discharge.【Methods】The study focuses on an arch dam with a height of 270 m,and CFD method is employed to simulate the flow field in the spillway tunnel and analyze the distribution of fluctuating pressures.Furthermore,fluid-structure coupling finite element method is used to simulate the worst case pulsating pressure and the vibration characteristics of the dam structure,and analyze the vibration mechanism of the high arch dam under discharge excitation.【Findings】The results show that the pulsating pressure inside the spillway of the arch dam is extremely complex,with the maximum and minimum values of the pulsating pressure of the surface sluice being 133.25 and 29.48 kPa,respectively,and the maximum and minimum values of the pulsating pressure of the middle sluice being 5274.99 and 953.24 kPa,respectively.The energy distribution of the pulsating pressure in frequency domain has low-frequency characteristics,with the main energy distribution in the frequency range of 0-10 Hz.Under discharge excitation,the total displacement of the arch dam shows a certain periodicity with changes of the pulsating pressure,and the total displacement gradually decays with the period.The total displacement reaches the maximum value of 0.2120 cm at 1.2 s,at the same time,the maximum values of equivalent stress is 1426.60 kPa,and equivalent strain is 7.49×10^(-5),the pulsating pressure shows the same trend in the vibration period,corresponding to the maximum value of the fluctuating pressure in the spillway tunnel.The variations of equivalent stress and equivalent strain of the arch dam are basically the same,and they have a complete correlation with the changes of pulsating pressure.

关 键 词：拱坝泄洪孔道 数值模拟 时均压力 脉动压力 流固耦合模型 振动机理 

分 类 号：TV642.4[水利工程—水利水电工程]