Oil-film instability simulation in an overhung rotor system with flexible coupling misalignment
Oil-film instability simulation in an overhung rotor system with flexible coupling misalignment
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DOI：
10.1007/s00419-015-0998-3
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发表时间：
2015-03
影响因子：
2.8
通讯作者：
Hui Ma;Xueling Wang;Heqiang Niu;B. Wen
中科院分区：
文献类型：
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作者：
Hui Ma;Xueling Wang;Heqiang Niu;B. Wen
针对滑动轴承高速运行时的油膜失稳问题，系统地研究了具有平行和角向失对的悬垂转子系统在启动和运行过程中的油膜失稳规律。建立了考虑陀螺效应的悬垂转子系统有限元模型，采用基于短长度轴承假设的非线性油膜力模型对滑动轴承进行了仿真。此外，通过将本文的仿真结果与已发表文献的实验结果进行对比，验证了有限元模型的有效性。在恒定角加速度下，模拟了平行位错（PM）和角位错（AM）对油膜失稳规律的影响。结果表明：在完全对准条件下，由于迟滞效应的影响，落跑过程中第一和第二振型失稳的发生次数小于爬升过程；在不对中条件下，耦合的不对中会延迟第一振型失稳的发生，减小其振动幅值。与调幅相比，在给定调幅条件下，多个频率分量的幅值更为明显。此外，在不同偏差条件下的助跑和减速过程中，根据旋转频率、一模旋/鞭频率、二模旋/鞭频率或它们的组合（如-），可以观察到主导振动能量的变化。
Aiming at the oil-film instability of the sliding bearings at high speeds, this paper systematically investigates oil-film instability laws of an overhung rotor system with parallel and angular misalignments in the run-up and run-down processes. A finite element (FE) model of the overhung rotor system considering the gyroscopic effect is established, and the sliding bearings are simulated by a nonlinear oil-film force model based on the assumption of short-length bearings. Moreover, the effectiveness of the FE model is also verified by comparing our simulation results with the experimental results in the published literature. In the run-up and run-down processes with constant angular acceleration, the effects of parallel misalignment (PM) and angular misalignment (AM) on oil-film instability laws are simulated. The results show that under the perfectly aligned condition, the onsets of the first and second vibration mode instability in the run-down process are less than those in the run-up process due to the hysteresis effect. Under the misalignment conditions, the misalignment of the coupling can delay the onset of the first vibration mode instability and decrease its vibration amplitude. In comparison with the PM, the amplitudes of multiple frequency components are more obvious under the given AM conditions. Moreover, in the run-up and run-down processes with different misalignment conditions, the variation of the dominant vibration energy was observed according to the rotating frequency, the first-mode whirl/whip frequency, the second-mode whirl/whip frequency, or the their combinations, such as–.