柔性转子转轴弯曲与不平衡耦合振动分析

Analysis of Flexible Rotor Vibration Under Coupled Action of Shaft Bend and Rotor Unbalance

针对某660 MW超临界汽轮机高中压转子上发生的不稳定振动问题,建立了转子弯曲与不平衡耦合动力响应有限元计算模型,并通过现场实例验证模型的准确性.结果表明:高转速运行时,汽轮机高压转子因配重面与失衡面不重合所引起的弯曲变形会导致振动的不稳定和持续爬升;动平衡试验应尽量在转子失衡面上进行;高压转子环境温度高,在外力作用下易发生蠕变,该现象在大型汽轮机高压转子上表现得更为明显.

To solve the problem of unstable vibration occurring in the HP-IP rotor of a 660 MW supercriti- cal steam turbine, a dynamic response model was set up for the system under coupled action of shaft bend and rotor unbalance using finite element method, of which the accuracy was verified with field experi- ments. Results show that the shaft bend caused by inconsistency between balancing and unbalance plane can not be neglected at high rotating speeds, since it may lead to the instability and increase of vibration. The balancing plane should be chosen on the unbalance plane as far as possible. High-pressure rotor is easy to have creep deformation under the effect of external force due to its high-temperature operation environ- ment; the phenomenon is even more obvious for high-pressure rotors of large steam turbine.