水轮发电机组轴系松动-碰摩耦合故障的动态响应

Dynamic Responses of Shaft System of Hydraulic Generator Set with Coupling Faults of Bearing Looseness and Rotor Rub-Impact

为研究非线性因素引起水轮发电机组轴承松动和转子碰摩故障,考虑定子与基础间的连接刚度和阻尼,建立了轴承松动与转子碰摩耦合故障下,具有6自由度的水轮发电机组轴系动力学模型.通过分岔图、Poincaré映射图和幅值谱图,分析了机组轴系随转频比和转子质量偏心变化的非线性动态响应.研究表明:机组转子和松动轴承有周期1运动、周期3运动及复杂的拟周期运动;在1/3倍频处存在幅值较大的低频谐波分量;随着转子质量偏心的增大,转子与定子间发生碰摩的区域不断增大,其动力学响应趋于复杂.

For the fault problems of the bearing looseness and rotor local rubbing caused by some nonlinear factors,a six-degree-of-freedom dynamic model for the hydraulic generator set with coupling faults of bearing looseness and rub-impact between rotor and stator was established,with the rigidity and damping between the stator and foundation being considered.The nonlinear dynamic behaviors of the shaft system were analyzed by Poincaré maps,amplitude spectrum and bifurcation diagrams,as the ratio of rotor circular frequency to its bending natural frequency and the rotor mass eccentricity varied.The research results revealed that various non-linear phenomena including periodic,period-three and quasi-periodic motions occurs at different circular frequencies and there are some low-frequency harmonics with large amplitude at the 1/3X component.Moreover,the circular frequency range of rub impact enlarges constantly and the dynamic responses of the system become more complex with the increasing of the rotor mass eccentricity.