Analytical study on effect of a circumferential feeding groove on unbalance response of a flexible rotor in squeeze film damper

1999 ◽  
Vol 32 (10) ◽  
pp. 559-566 ◽  
Author(s):  
Qingchang Tan ◽  
Xiaohua Li
Keyword(s):  
Analytical Study ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Squeeze Film Damper ◽  
Unbalance Response

Unbalance Response of a Flexible Rotor Supported by a Squeeze Film Damper

1998 ◽  
Vol 120 (1) ◽  
pp. 32-38 ◽  
Author(s):  
J. Y. Zhao ◽  
I. W. Linnett ◽  
L. J. McLean
Keyword(s):  
Air Entrainment ◽  
Experimental Results ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Film Rupture ◽  
Squeeze Film Damper ◽  
Film Model ◽  
Unbalance Response ◽  
Rupture Pressure ◽  
Spring Type

This paper investigates the unbalance response of a squeeze film damper-mounted flexible rotor, Both concentric and eccentric damper operations are examined. Comparison between predicted and experimental results shows that the ’0’ film model is preferred to the π film model. Near the first pin-pin critical speed the ’0’ film model underestimates the damping effect and overestimates the centralizing force of the damper. By choosing a lower film rupture pressure in the theoretical model, better matches to the experimental results are obtained. The effects of air entrainment are shown to produce unsteady responses and jump phenomena of softening spring type. It is concluded that damper models having constant film rupture pressures do not truly represent the cavitation problem in squeeze film dampers.

A theoretical and experimental investigation into the vibration response of a flexible rotor and squeeze-film damper assembly

2001 ◽  
Vol 215 (10) ◽  
pp. 1251-1269 ◽  
Author(s):  
C-C Siew ◽  
M Hill ◽  
R Holmes ◽  
M Brennan
Keyword(s):  
Harmonic Balance ◽  
Three Dimensional ◽  
Harmonic Balance Method ◽  
Vibration Response ◽  
Mode Shapes ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Linear Vibration ◽  
Squeeze Film Damper ◽  
Good Agreement

This paper presents two efficient methods to calculate the unbalance vibration response of a flexible rotor provided with a squeeze-film damper (SFD) with retainer springs. Both methods are iterative and combine the harmonic balance and receptance approaches. The first method, called the modified iteration method (MIM), is suitable for predicting the three-dimensional mode shapes of a concentric SFD-rotor system. The second method, called the modified harmonic balance method (MHBM), is developed to calculate the non-linear vibration response of a flexible shaft provided with either a concentric or eccentric SFD. The system is also investigated experimentally under different conditions. The predictions computed by these methods are compared with experimental measurements and reasonably good agreement is obtained.

Electro-Rheological Multi-layer Squeeze Film Damper and Its Application to Vibration Control of Rotor System

1999 ◽  
Vol 122 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Yao Guozhi ◽  
Yap Fook Fah ◽  
Chen Guang ◽  
Meng Guang ◽  
Fang Tong ◽  
...  
Keyword(s):  
Vibration Control ◽  
Large Amplitude ◽  
Critical Speed ◽  
Reynolds Equation ◽  
Control Method ◽  
Rotor System ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Unbalance Response ◽  
Er Damper

In this paper, a new electro-rheological multi-layer squeeze film damper (ERMSFD in short) is designed first and the constitutional Reynolds equation is established. Then the behavior of the rotor system is analyzed, the vibration around the first critical speed is suppressed and an on/off control is proposed to control the large amplitude around the first critical speed. A control method is used to suppress the sudden unbalance response. Finally, experiments are carried out to investigate the behavior of the rotor system to prove the effectiveness of the ER damper to suppress the vibration around the critical speed and the sudden unbalance response. [S0739-3717(00)00301-9]

scholarly journals A Theoretical Investigation of an Overhung Flexible Rotor Mounted on Uncentralized Squeeze-Film Damper Bearings and Flexible Supports

1982 ◽  
Author(s):  
R. A. Cookson ◽  
Xin-Hai Feng
Keyword(s):  
Theoretical Study ◽  
Effective Means ◽  
Complex Model ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Squeeze Film Damper ◽  
Surrounding Structure ◽  
Turbine Disc ◽  
Flexible Supports ◽  
Selection Of

Previous investigations have shown that the uncentralized type of squeeze-film damper is an effective means of reducing the transmission of unbalance forces into the supporting structure. In this theoretical study a more complex model, which includes an overhung “fan” disc and a noncentral “turbine” disc, has been employed. This model represents the conventional gas turbine somewhat closer than does the previously studied single disc system. This investigation has shown that it is possible to minimize the force transmitted into the surrounding structure by a careful selection of squeeze-film damper characteristics, although it may be found that some larger amplitudes of motion accompany the minimized transmissibility.

Rotordynamic Evaluation of an Advanced Multi-Squeeze Film Damper: Imbalance Response and Bladeloss Simulation

1991 ◽  
Author(s):  
J. F. Walton ◽  
H. Heshmat
Keyword(s):  
Steady State ◽  
Rotor System ◽  
Squeeze Film ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Flexible Rotor ◽  
High Eccentricity ◽  
Squeeze Film Damper ◽  
Wide Range ◽  
Damper Design

In this paper results of rotordynamic response and transient tests of a novel, high load squeeze film damper design, are presented. The spiral foil multi-squeeze film damper has been previously shown to provide two to four fold or larger increases in damping levels without resorting to significantly decreased damper clearances or increased lengths. By operating with a total clearance of approximately twice conventional designs, the non-linearities associated with high eccentricity operation are avoided. Rotordynamic tests with a dual squeeze film configuration were completed. As a part of the overall testing program, a flexible rotor system was subjected to high steady state imbalance levels and transient simulated bladeloss events for up to 0.254 mm (0.01 in) mass c.g offset or 180 gm-cm (2.5 oz-in) imbalance. The spiral foil multi-squeeze film damper demonstrated that the steady state imbalance and simulated bladeloss transient response of a flexible rotor operating above its first bending critical speed could be readily controlled. Rotor system imbalance sensitivity and logarithmic decrement are presented showing the characteristics of the system with the damper installed. The ability to accommodate high steady state and transient imbalance conditions make this damper well suited to a wide range of rotating machinery, including aircraft gas turbine engines.

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