透平机械三转子四支撑轴系不平衡振动特性

针对汽轮机、压缩机等透平机械三转子四支撑轴系经常发生不平衡振动现象,研究轴系中各转子振型不平衡的响应特性。采用有限元法构建三转子四支撑轴系动力学有限元模型,分别在各跨转子上施加一阶、二阶弯曲振型不平衡,分析高低转速下轴系的涡动轨迹,以揭示各转子振型不平衡与轴系振动响应的关联。通过搭建的三转子四支撑轴系转子振动实验台,开展各跨转子不平衡激励下轴系振动响应测试,分析共振点和幅、相频特性,得出结论:这类轴系跨内加重振动响应由轴系模态振型和激励类型共同决定,兼具有转子外伸端振动特性。该结论可为消除这类三转子四支撑轴系不平衡故障提供参考。

Vibration Characteristics for Unbalance of Turbomachinery Shafting with Three-Rotor and Four-Support

In the light of the unbalanced vibration in the shafting with three-rotor and four-support such as the steam turbine unit and compressor unit, the vibration characteristics of each rotor with mode shape unbalance is developed. First, the dynamics finite element model of shafting with three-rotor and four-support is built. The first and second bending mode shape unbalanced excitations are applied to each rotor of shafting respectively, and the shaft response analysis of shafting are taken. The relationship between the unbalanced excitation type of each rotor and shafting response is confirmed. Then, the rotor simulation experiment rig for shafting with three-rotor and four-support is designed to investigate the support responses and analyze the resonance points, magnitude-frequency and phase-frequency characteristics due to unbalanced excitation. It shows that the vibration characteristics of shafting with added unbalance inside of rotor is determined collaboratively by mode shape and excitation type. Additionally, the overhung rotor vibration characteristics is obvious. It is beneficial to suppress the unbalance vibration fault of this kind of shafting with three-rotor and four-support.