某型核能汽轮发电机组轴系振动的稳定性分析及动平衡治理

Stability analysis and dynamic balance treatment of shafting vibration in a nuclear steam turbine generator unit

国内某大型核能汽轮发电机组自投产后,多台次出现轴系振动的连续性波动现象,波动幅度大且周期长。理论分析和检修记录推测为汽轮发电机密封瓦卡涩引发的莫顿效应所致。建立简化模型并对振动数据进行拟合,计算出初始不平衡质量及热变量分别对应的振动分量。分析认为热变量导致的振动分量占比小,机组轴系振动稳定性不受影响。应用该方法快速计算出转子初始不平衡质量对应的振动分量,进而实施动平衡试验可有效降低机组振幅。对某核能机组的现场工程实践经验验证了本方法的正确性。

Continuous shafting vibration fluctuation occurred on several large scale nuclear steam turbine generator units after being put into operation, with large fluctuation range and long period. It was speculated as Morton Effect which happened due to jamming of sealing pad in steam turbine generator unit, according to theoretical analysis and maintenance records. A simplified model was established to fit the vibration data, and the vibration components corresponding to the initial unbalanced mass and thermal variables were calculated. Analysis shows that, because the proportion of vibration component corresponding to thermal variable was small, the shaft system stability of the unit was not affected. By this new method, the vibration component corresponding to the initial unbalance mass of the rotor was quickly calculated and the vibration amplitude can be effectively reduced through the dynamic balance test. The correctness of the model has been verified by the field engineering practice in a nuclear power station.