对实际大型汽轮机转子-密封-轴承系统建立了具有超大规模维数的非线性动力学模型,该模型考虑了密封的非线性激振力、可倾瓦轴承的弹性支承力、转子的阻尼力、不平衡质量力和重力.采用Newmark方法对其进行数值求解,模拟出转子升速过程中汽流激振现象的典型特征和发生汽流激振的失稳转速,并且得到系统参数对转子不平衡响应和稳定性的影响规律.结果表明:适当的增大转子的阻尼、密封的半径间隙和密封流体轴向流速可提高转子发生汽流激振的失稳转速,这为在设计和运行中提高实际大型汽轮机转子-密封-轴承系统的稳定性提供了参考依据.%Nonlinear dynamic model of a rotor -seal-bearing system with ultra-large-scale dimension for an actual steam turbine was proposed considering the non-linear exciting force of seal, the elastic support force of tilting-pad bearing, the damping force, the imbalance force and the gravity of rotor. The unbalance response of the rotor was numerically calculated with Newmark method. The typical characteristic of self-excited vibration and the threshold speed of instability induced by the seal-force were revealed. The effects of the system parameters on dynamic response and instability were also investigated. The results showed that appropriate increase in rotor damping, seal's radius clearance and axial velocity of seal fluid can improve the stability of the system and raise the threshold speed of instability. The results provided a reference for improving the stability of large steam turbine.
展开▼
