1.College of Water Resources Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2.Henan Key Laboratory of Water Resources Conservation and Intensive Utilization in the Yellow River Basin, Zhengzhou 450046, China;
3.School of Infrastructure Engineering, Dalian University of Technology, Dalian 116023, China;
4.China Water Northeast Investigation, Design and Research Co., Ltd., Changchun 130021, China
Abstract：Aiming at the vibration problem of the rub-impact rotor-runner system in axial-flow hydrogenerator set caused by misalignment of coupling Angle, based on the modified LuGre friction model,the expressions for the rub-impact forces of runner blades under the misalignment fault are derived in this paper. On this basis, the system dynamic model is established which comprehensively considers external excitations including unbalanced magnetic pull force. The influence of the misalignment angle on the vibration characteristics of the system is studied by numerical method, and the stability of the periodic solution of the system with the speed as the control variable is analyzed based on Floquet theory. The results show that the existence of misalignment significantly changes the dynamic characteristics and increases the possibility of system instability. In addition, the effect of the misalignment angle on the vibration response of the rotor and the runner is quite different. With the increase of the misalignment angle, the runner vibration varies obviously and the degree of rub-impact is worse. The research results in this paper can provide references for the safe operation and stability analysis of axial-flow hydrogenerator set.
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