常规岛汽机旁路调节阀流激共振研究

Research on flow-induced resonance of conventional island steam turbine bypass control valve

针对核电常规岛汽机旁路阀小开度下易发生振动的问题,设计了一种汽机旁路阀,基于流激共振理论及流固耦合方法,对其阀芯组件进行流激振动分析。选取30%开度工况,采用CFD软件进行瞬态流场仿真分析,以获得阀芯组件流固耦合处的流体压力脉动时域信息,将时域信息进行快速傅里叶变换(FFT)得到流体作用于阀芯组件的激振频率。采用ANSYS Workbench软件对典型开度进行流固耦合模态分析,得到阀芯组件的模态频率。通过流体激振频率与模态频率对比进行进一步分析研究。结果表明:典型工况下该型调节阀流体激振的频率区为848~1 272 Hz,阀芯组件结构1阶固有模态频率为3 170.1 Hz,随着阶数增大依次递增,6阶模态频率与流体激振频率均不接近,因此该型汽机旁路阀在典型工况下不会发生流激共振,验证了该设计的有效性,可为同类常规岛汽机旁路调节阀防共振结构设计提供参考。

For the problem that the bypass valve of the steam turbine bypass valve in the nuclear power conventional island is prone to vibration at small openings,a steam turbine bypass valve was designed,and then the flow-induced vibration analysis of the valve core assembly was carried out based on the flow-induced resonance theory and the fluid-solid coupling method.The working condition of 30%opening was selected,and CFD software was use to conduct transient flow field simulation analysis to obtain the time-domain information of fluid pressure fluctuation at the fluid-solid coupling of the valve core assembly,and perform fast Fourier transform(FFT)on the time-domain information to obtain the excitation frequency at which the fluid acts on the spool assembly.ANSYS Workbench software was used to conduct fluid-solid coupling modal analysis on typical openings to obtain the modal frequency of the valve core assembly.Further analysis and research were carried out by comparing the fluid excitation frequency with the modal frequency.The results show that under typical working conditions,the fluid excitation frequency range of this type of control valve is 848~1272 Hz,the first-order natural mode frequency of the valve core assembly structure is 3170.1 Hz,and as it successively increases with the increase of the number of orders,and the sixth-order modal frequencies are not close to the excitation frequency of the fluid,so this type of turbine bypass valve will not experience flow-induced resonance under typical operating conditions,which verifies the feasibility of this design method and can be used for the anti-resonance structure design of conventional island turbine bypass control valves for reference.