Abstract：Recently，large capacity steam turbines have come into wider use and have been designed to perform at even higher performance specifications. As we all know, it’s hard to maintain the concentricity of rotor-bearing system during operating, especially for multi-rotors within specified levels of vibration. Rotor vibration could be caused by many reasons. Mass unbalance and bent shaft are amongst the most frequently occurring of these reasons. Mass unbalance and bent shafts both give force excitation at a frequency corresponding to once per revolution. Taking a LP B rotor of a 1000MW USC steam turbine as an example, this paper studies the lateral vibration of the LP B rotor based on finite element. Responses of mass unbalance and bent shaft are analyzed and compared. Calculation results show that, if the rotor is spinning at a constant speed, then it exhibits whirl and it is impossible to deduce whether that whirl is caused by an out-of-balance or a bent. The response of the rotor supported by isotropic bearings, only forward whirl is excited whereas both forward and backward whirl are excited when rotor supported by anisotropic bearings. In case cross coupling stiffness, one cross- coupling term is positive and the other is negative, can make rotor unstable despite the presence of damping.
吴文青;谢诞梅;杨毅;胡鹏飞. 具有初始弯曲的1000MW汽轮机低压转子的振动特征分析[J]. , 2014, 33(17): 150-153.
Van Thanh Ngo;Danmei Xie;Yi Yang;Pengfei Hu.
ANALYSIS OF VIBRATION BEHAVIOR FOR THE BENT ROTOR OF A 1000MW TURBINE . , 2014, 33(17): 150-153.
2014, Vol. 33 
