为了避免叶片在运行过程中发生共振现象，针对某汽轮机低压次末级动叶片，采用全三维有限元分析方法对整圈叶片-叶轮模型进行振动特性分析。结果表明：初始围带厚度下1阶8节径振型在工作转速范围内出现“三重点”共振，不满足频率避开率要求，容易发生共振，需要进行调频改进；通过改变叶片围带厚度和围带接触面长度进行调频优化，并通过试验验证了调频后“三重点”转速与工作转速避开率满足要求，调频方案有效。

In order to avoid the resonance phenomenon of the blade during operation,the full threedimensional finite element analysis method is used to analyze the vibration characteristics of the whole bladeimpeller model for the lowpressure penultimate stage moving blade of a steam turbine.The results show that the three key resonance occurs in the firstorder vibration mode of the 8pitch diameter under the initial shroud thickness within the working speed range,which does not meet the frequency avoidance rate requirements and is prone to resonance,so frequency modulation improvement is needed.The frequency modulation is optimized by changing the thickness of the blade shroud and the length of the shroud contact surface,and the test verifies that the three key speed and the working speed avoidance rate meet the requirements after the frequency modulation,and the frequency modulation scheme is effective.

TK263.3