核动力系统蒸汽发生器U形管流致振动数值模拟

Numerical Simulation of Flow-induced Vibration of U-tube in Steam Generator of Nuclear Power System

蒸汽发生器传热管流致振动现象可能威胁核动力系统的运行安全,是蒸汽发生器设计及运行中必须要考虑的技术问题。本文应用计算流体动力学软件FLUENT,建立传热管绕流截面的等效二维计算模型,通过用户自定义函数(UDF)求解结构动力学方程,再结合动网格模型,实现对蒸汽发生器U形管流致振动现象的流固耦合数值模拟。计算得到传热管固定、涡激振动条件下流体的升力系数、阻力系数以及相应的涡脱频率,同时,获得了传热管的涡激振动位移。最后,揭示了雷诺数及传热管约束方式对传热管振动的影响,为蒸汽发生器的安全分析和优化设计提供参考。

The flow-induced vibration phenomenon of steam generator U-tube may threaten the operation safety of nuclear power system,which must be considered in the design and operation of steam generator.In this paper,the CFD software FLUENT is used to establish the equivalent two-dimensional calculation model of the flow around the heat transfer tube.The structural dynamics equation is solved by the user-defined function(UDF),and then combined with the dynamic grid model,the fluid structure coupling numerical simulation of the flow-induced vibration phenomenon of the steam generator U-tube is realized.The lift coefficient,drag coefficient and vortex shedding frequency of the fluid under the condition of fixed tube and vortex-induced vibration are calculated,and the vortex-induced vibration displacement of the tube is obtained.Finally,the influence of Reynolds number and tube restraint mode on tube vibration is revealed.The work in this paper can provide reference for safety analysis and optimization design of steam generator.