Experiment on the characteristics of torsional vibration of rotor-to-stator rub in turbomachinery

By use of the DK-II torsional vibration measuring system, the characteristics of torsional vibration of a rotor with rotor-to-stator rub an studied. It can be concluded that the measured natural torsional frequency (f(rub)) with rub is higher than the one (f(ori)) without rub. When rub happens, if the rotating frequency is higher than f(rub), torsional vibrations with a measured natural torsional frequency (f(rub)) and 1x, 2x are excited; if the rotating frequency is between f(rub) and f(ori), the torsional vibration which is so called resonance (one-time rotating frequency) is excited; if the rotating frequency is lower than f(ori), torsional vibrations with one-time rotating frequency and f(rub) are excited, and a small torsional vibration with 2x is excited too. (C) 2000 Elsevier Science Ltd. All rights reserved.