大型水电站厂房结构流固耦合振动特性研究

Study of fluid-solid interaction vibration characteristics of the large scale power-house structure

浅析了流固耦合振动机理,探讨了流固耦合振动问题的分析方法,分析了厂房结构同流体相互作用的复杂的边界条件,并利用强耦合法把有限元理论和声场理论结合起来,计算了某大型水电厂房流固耦合振动特性,并与无流体存在情况下的厂房振动特性进行了比较,详细阐述了两者之间的藕联特点：流体的存在对发电机层以上结构和下游副厂房结构的振型无明显影响,但对于蜗壳外围大体积混凝土结构影响却较大,其对应振型的频率值相差在10%～25%之间。对于解决水电厂房结构与流体耦合振动问题的三维数值模拟提供了一种可靠而有效的方法,同时,对于解决其它类型的流固耦合问题也具有重要的参考价值。

The vibration theory of fluid-solid interaction is analysed, the methods of analysis on fluid-solid interaction is discussed, the complicated boundary condition of interaction between power-house structure and its internal fluid is introduced and the vibration characteristics of large-scale power house structure are calculated by the strong-interaction method combined with finite element theory and acoustics theory. By comparing with characteristics of power house structure without fluid, their interaction characteristics are particularly expatiated, internal fluid has no effect on structures of electrical machine and auxiliary house, but it has big effect on large volume concrete located near spiral case that numerical values of natural frequencies are variated from 10% to 25 %. The reliable and effective method for 3D numerical simulation is provided for vibration problem of interaction between powerhouse structure and its internal fluid. Also, the method is of important value for solving other fluidsolid interaction problems.