摘要
试验研究核电汽轮机低压转子与端部汽封体发生动静摩擦时的振动特征、产生机理与处理方法。某核电汽轮机调试期间,发现低压转子的各振动测点振幅持续异常缓慢爬升。通过振动频谱、振幅趋势、机组运行工况及低压缸结构特点等诊断认为受第二台循环水泵启动的影响,低压缸缸体发生下凹变形导致低压转子与端部汽封体发生了轻微动静摩擦,采取"磨合"运行的方式处理,约5h后振动缓慢下降并恢复正常。解体检查发现端部汽封体下半部分的齿尖与轴颈处存在明显磨损痕迹。机组启动过程中,当凝汽器抽真空后实测汽封体下沉变形量约1mm,容易诱发汽封体与轴颈发生动静摩擦。对低压转子实施反相动平衡加重提高平衡精度后,振动基数大幅降低,避免了该类动静摩擦;研究还发现同比火电汽轮机,核电汽轮机低压转子的动平衡影响系数偏低。
The vibration characteristic, mechanism and treatment method of friction between the low pressure rotor and the end seal of nuclear power stream turbine are studied. During the commissioning of a nuclear power stream turbine, it is found that the vibration amplitudes of low pressure rotors increased slowly and slowly. After analyzing the vibration spectrum, amplitude trend, operating condition, low pressure cylinder structure and so on, it＇s diagnosed that slight friction happens between low pressure rotor and end seal body which arose by low pressure cylinder~ distortion. And the distortion occurs by concave due to the second circulating pump＇s starting suddenly. 5 hours later, the vibration values decreased slowly and returned to normal by running-in operation mode. It is found that there are obvious wear marks on the tips of the lower part of the seal body, and also on the gudgeon journal ~s surface. During the start-up process of the unit, the deformation of the seal body is measured which is about lmm when the Condenser evacuated. After adding reverse balancing weights to improve low pressure rotor＇s balancing precision, the friction avoided successfully by the vibration level reduced greatly. The study has also found that compared to the thermal power steam turbine＇s low pressure rotor, the dynamic balance coefficient of nuclear power stream turbine is lower.
出处
《汽轮机技术》
北大核心
2017年第4期306-309,共4页
Turbine Technology
关键词
核电汽轮机
低压缸
摩擦
振动
端部汽封体
nuclear power steam turbine
low pressure cylinder
friction
vibration
seal body
