0
Research Papers

Experimental Researches on Reducing the Critical Acceleration That Induces Sustainable Rotor Rubbing

[+] Author and Article Information
Wang Shimin1

Associate Professor Department of Dynamics and Control, Aeronautic Science and Engineering School,  Beihang University, Beijing 100191, P.R. Chinashiminwang@buaa.edu.cn

Zhang Xingye

Graduate Student Department of Dynamics and Control, Aeronautic Science and Engineering School,  Beihang University, Beijing 100191, P.R. Chinazxy@ase.buaa.edu.cn

1

Corresponding author.

J. Vib. Acoust 133(6), 061007 (Oct 18, 2011) (9 pages) doi:10.1115/1.4004664 History: Received November 16, 2009; Accepted May 02, 2011; Published October 18, 2011; Online October 18, 2011

When an imbalanced rotor is sped up to pass through the critical speed with a constant acceleration, sustainable rubbing can be induced if the maximum vibration amplitude of the rotor exceeds the gap. This is the so-called stiffness increase or stiffening phenomenon. The maximum vibration amplitude is dependent on the magnitude of the rotor’s acceleration: the smaller the acceleration, the larger the maximum amplitude. Thus, there exists a critical acceleration: for accelerations smaller than the critical one, the sustainable rubbing will be induced. To prevent such unwanted rubbing, the rotor acceleration or the gap must be large enough. Since the acceleration is limited by the power/torque of driving system while large gap decreases the efficiency of some rotating machines, smaller driving power and higher efficiency have to be content with the second best. In this paper, the phase modulation method is applied to reduce the critical acceleration, and experiments are conducted on a setup designed to test the phase of the imbalanced force. The method is to operate the rotor with a scheduled, not continuously increased speed: when accelerated to a given speed, the rotor is decelerated to an assigned speed, and then accelerated again. Numerical and experimental results show that the critical acceleration is reduced about 50% by this technique. A prerequisite for this method is that the rotor’s speed is controllable.

Copyright © 2011 by by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Experimental setup, test, and control equipments: 1: disc, 2: disc legs, 3: motor, 4: rotor, 5: ring, 6: ring legs, 7: motor driver, 8: motion controller, 9: high-speed camera

Grahic Jump Location
Figure 2

Side cut-open view of the setup

Grahic Jump Location
Figure 3

Adopted coordinate system

Grahic Jump Location
Figure 4

The critical acceleration defined by the rotor’s characteristic of amplitude-frequency being sped up

Grahic Jump Location
Figure 5

Vibration amplitude with phase modulation in the same acceleration as the normal case

Grahic Jump Location
Figure 6

Phase difference with phase modulation in the same acceleration as the normal case

Grahic Jump Location
Figure 7

Vibration amplitude with phase modulation when the acceleration is reduced by 50%

Grahic Jump Location
Figure 8

Phase difference with phase modulation when the acceleration is reduced by 50%

Grahic Jump Location
Figure 9

The effect of friction on the phase difference in the normal case

Grahic Jump Location
Figure 10

The effect of friction on the rubbing duration in the normal case

Grahic Jump Location
Figure 11

The phase difference for different friction with phase modulation

Grahic Jump Location
Figure 12

The vibration amplitude for different friction with phase modulation

Grahic Jump Location
Figure 13

Phases of the rotor and disc

Grahic Jump Location
Figure 14

Displacement diagrams of the disc

Grahic Jump Location
Figure 15

Displacements of the disc with continuous rubbing in the acceleration of 3.8r/s2

Grahic Jump Location
Figure 16

Displacements of the disc with phase modulation in the acceleration of 2r/s2

Grahic Jump Location
Figure 17

The phase difference with phase modulation in the acceleration of 2r/s2, calculated from the displacements of the disc

Grahic Jump Location
Figure 18

The scheduled speed of the rotor/motor

Grahic Jump Location
Figure 19

Displacements of the disc considering the deviation of the returning speed

Grahic Jump Location
Figure 20

Displacements of the disc considering the deviation of the braking speed

Grahic Jump Location
Figure 21

Schematic diagrams of rotor models

Grahic Jump Location
Figure 22

Forces exerted on discs and velocities at contact points

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In