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抽水蓄能电站抽水开机过程中充水保压蜗壳非线性接触流激响应研究
Research on Nonlinear Contact Flow Excitation Response of Preloading Spiral Case during Pump Start-up Process of Pumped Storage Power Station
【摘要】 为了研究保压值对充水保压蜗壳在机组运行期的影响,本文针对一台原型水泵水轮机组的保压蜗壳-混凝土结构进行了流固耦合分析。利用RANS方法结合SST k-ω湍流模型,对机组抽水开机过程中的流场进行了数值计算,并以流场压力为边界条件,进行了蜗壳与厂房混凝土结构场的有限元计算。分析了蜗壳内的压力场、速度场变化规律,并比较了不同保压值下蜗壳与混凝土的应力应变分布情况及接触状态。结果表明:机组蜗壳中的压力变化主要受导叶打开规律影响,整个开机过程中蜗壳内的流动易出现漩涡,受导叶开度与周向不均匀流动的综合因素影响。蜗壳在不同保压取值下变形及应力变化趋势基本一致,位移主要是受初始保压间隙的影响,而应力变化则主要受内部压力波动的影响。混凝土提前接触会导致开裂风险区域随保压值的增大而增加。在本研究工况中,最小保压值3.2MPa对于降低混凝土的开裂风险更有利,说明在实际工程中增大保压值并不能总是保证混凝土结构更安全。
【Abstract】 To study the influence of the pressure preloading value on the preloading spiral case during the operation period of the unit, this paper conducted a fluid structure coupling analysis on the preloading spiral case concrete structure of a prototype pump-turbine unit. The RANS method combined with the SST k-ω turbulence model was used to numerically calculate the flow field during the pump start-up process of the unit. The finite element calculation of the spiral case and the concrete structure field of the factory building was carried out with the flow field pressure as the boundary condition. The pressure field and velocity field changes inside the spiral case were analyzed, and the stress-strain distribution and contact state of the spiral case and concrete under different pressure preloading values were compared. The results show that the pressure changes in the spiral case of the unit are mainly affected by the opening law of the guide vanes. During the entire start-up process, vortices are prone to occur in the flow inside the spiral case, which is influenced by the combined factors of the opening angle of the guide vanes and uneven circumferential flow. The deformation and stress changes of the spiral case under different preloading pressure values are basically consistent. The displacement is mainly affected by the initial preloading pressure gap, while the stress changes are mainly affected by internal pressure fluctuations. Early contact with concrete can lead to an increase in the risk of cracking in the area as the preloading pressure value increases. In this study, the minimum preloading pressure value of 3.2MPa is more favorable for reducing the risk of concrete cracking, indicating that increasing the holding pressure value in practical engineering does not always guarantee safer concrete structures.
【Key words】 pumped storage power station; spiral caseing; preloading spiral caseing; contact; fluid structure coupling;
- 【文献出处】 大电机技术 ,Large Electric Machine and Hydraulic Turbine , 编辑部邮箱 ,2025年01期
- 【分类号】TV743
- 【下载频次】10