Abstract
Rub-impact fault causes complicated vibration to the rotor system and is one of the main reasons for the system instability. The increment transfer matrix method is used to analyze the dynamic response of the coupled bending and torsional vibrations of turbo-generator shafts with rub-impact in this work. Aimed at a turbo-generator unit with different rotating speed, the vibration character of rub-impact fault is analyzed. The research results show that the influence of rotating speed on vibration amplitude is obvious. When the speed is lower than the first order inherent frequency, rubbing will cause bending and torsional vibration amplitudes of each shaft segment increase largely. When the speed is higher than the first order inherent frequency, vibration amplitudes slightly change by rubbing. The sensitive to rubbing position is different for increased vibration amplitude of each shaft segment. The shaft segment is more near to the rubbing position, the increased vibration amplitude is more obvious.
Highlights
With the development of technology, the demand for performance of rotating machinery is becoming greater, the radial gap of rotor to stator smaller, this has led to the frequent occurrence of the rotor-to-stator rub, especially between the rotor and seal or the blade tip and the envelope
For a turbo-generation machine, operating at high speed, the coupled bending and torsional vibrations characteristics may be considerably different from those obtained by uncoupled independent analyses
1) The expressions of bending vibration Adopting the multi-mass model, the rotor system of turbo-generator unit is divided into several rigid disks and elastic shafts
Summary
With the development of technology, the demand for performance of rotating machinery is becoming greater, the radial gap of rotor to stator smaller, this has led to the frequent occurrence of the rotor-to-stator rub, especially between the rotor and seal or the blade tip and the envelope. The behavior of the bending vibration of a rotor with rub-impact has been studied throughly [1–6]. It can be known from the rotor dynamic equations that the torsional vibration is as an important part as the vibration. For a turbo-generation machine, operating at high speed, the coupled bending and torsional vibrations characteristics may be considerably different from those obtained by uncoupled independent analyses. . According to D'Alembert principle, the increment equations of shear force and bending moment are obtained as: includes low vibration and noise characteristics, an investigation of the coupled bending and torsional vibrations phenomenon would be desirable. The research on the behavior of the torsional vibration of a rotor/stator system with rub is very significant for diagnosing rotating machinery. Simple disc rotor model is adopted widely, that can not really be used to analyze complex rotor system like a turbo-generator unit[7-10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
