Dynamic Analysis on Hydraulic Generator Rotors With Coupling Faults of Misalignment and Rub-impact
HUANG Zhi-wei, ZHOU Jian-zhong, ZHANG Yong-chuan (College of Hydroelectric and Digitalization Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei Province, China)
This paper researched on the rotor system of a hydroelectric generating set. Analyzing on the fault of local rubbing caused by compatible misalignment of rotors, a dynamic model for the rotor system with misalignment and rub-impact was established. Then the dynamic behaviors of this system, which varied with the values of parallel misalignment and declination, were investigated by using numerical integral method. By virtue of bifurcation diagrams, Poincaré maps, orbits, time histories and frequency spectrum diagrams, the nonlinear dynamic responses of the generator rotor and hydraulic turbine rotor with coupling faults were analyzed. The results confirmed rich nonlinear motions such as periodic motion and quasi-periods with different values of parallel misalignment and declination. Moreover, the process of rub-impact is so complex that many low frequencies with large amplitude are in the range of 0.3~0.4 X. These results provide important theoretical references for the safety operation of hydroelectric generating sets and the exact identification of the faults in rotating machinery.