An Appraisal of a Proposed Active Squeeze Film Damper

1991 ◽  
Vol 113 (4) ◽  
pp. 750-754 ◽  
Author(s):  
C. Mu ◽  
J. Darling ◽  
C. R. Burrows
Keyword(s):  
Theoretical Model ◽  
Vibration Control ◽  
Numerical Experiments ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Flexible Rotor ◽  
Oil Film ◽  
Squeeze Film Damper

A theoretical model for an active squeeze film damper (SFD) is introduced. The design makes it possible to change the radial clearance and land length of the SFD by adjusting the position of the damper ring. Expressions for the oil film forces are obtained. The vibration control of a flexible rotor is taken as an example of the application of the new design. The possibility of controlling rotor vibrations is demonstrated by means of numerical experiments.

The Effect of Journal Misalignment on the Oil-Film Forces Generated in a Squeeze Film Damper

1983 ◽  
Vol 105 (3) ◽  
pp. 560-564 ◽  
Author(s):  
R. A. Cookson ◽  
X. H. Feng ◽  
S. S. Kossa
Keyword(s):  
Computational Procedure ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Oil Film ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Unbalance Force ◽  
Orbit Size ◽  
Journal Misalignment ◽  
Typical Calculation

Squeeze film damper performance is usually assessed on the assumption that the axis of the journal is parallel to that of the bearing housing. For many practical cases, for example that of the overhung fan shaft in an aero gas turbine, these two elements are unlikely to be parallel, even when self-aligning bearings are used. In this theoretical study an attempt has been made to evaluate the effect of misalignment on the magnitude of the oil-film forces produced in a squeeze film damper bearing, and to this end a computational procedure has been established. From the results reported in this paper, it has been clearly shown that the effect of misalignment in a two-land, squeeze film damper can lead to a significant increase in the transmission of unbalance force through the oil film, As an example, data from a previously reported investigation into the performance of a simple two-bearing model with a single centrally supported disk have been used in a typical calculation. The results from this computation indicated that the oil-film forces generated, could have been several times greater than those calculated on the assumption that the journal and bearing housing were parallel. Unfortunately, there do not appear to be any clear guidelines to lay down to the designers of squeeze film dampers at this moment, in relation to journal misalignment. In general, the effect of misalignment is strongest when the ratio of land-length to radial clearance is greatest, when large unbalance is being accommodated, and when the orbit size is large. In our own analytical studies, the effect of misalignment is allowed for whenever the angle of misalignment is greater than 0.0005 radians.

scholarly journals An Investigation Into the Effect of Side-Plate Clearance in an Uncentralized Squeeze-Film Damper

1983 ◽  
Author(s):  
R. A. Cookson ◽  
L. J. Dainton
Keyword(s):  
Experimental Investigation ◽  
Rolling Contact ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Flexible Rotor ◽  
Jump Phenomenon ◽  
Side Plate ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Experimental Rig

An experimental investigation has been carried out into the influence of side-plate flow restrictors on the performance of a squeeze-film damper bearing. The experimental rig used was a flexible rotor with a disc positioned mid-way between two squeeze-film damper bearings. One of the squeeze-film dampers was fitted with side-plates which could be adjusted and accurately located with respect to the squeeze-film damper journal. It has been found that the influence of the side-plate clearance on the ability of the squeeze-film damper to reduce the amplitude of the central disc can be considerable if the side-plate clearance is less than the radial clearance. As the side-plate clearance reduces towards zero, the effectiveness of the squeeze-film damper diminishes until the amplitudes obtained are the same as those measured when the rolling-contact bearing is rigidly supported. An interesting type of precessing elliptical orbit was discovered for conditions where the ‘jump’ phenomenon was operating.

An Investigation Into the Effect of Side-Plate Clearance in an Uncentralized Squeeze Film Damper

1983 ◽  
Vol 105 (4) ◽  
pp. 935-940
Author(s):  
R. A. Cookson ◽  
L. J. Dainton
Keyword(s):  
Rolling Contact ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Flexible Rotor ◽  
Jump Phenomenon ◽  
Side Plate ◽  
Squeeze Film Damper ◽  
Central Disk ◽  
Squeeze Film Dampers ◽  
Experimental Rig

An experimental investigation has been carried out into the influence of side-plate flow restrictors on the performance of a squeeze film damper bearing. The experimental rig used was a flexible rotor with a disk positioned midway between two squeeze film damper bearings. One of the squeeze film dampers was fitted with side plates that could be adjusted and accurately located with respect to the squeeze film damper journal. It has been found that the influence of the side-plate clearance on the ability of the squeeze film damper to reduce the amplitude of the central disk can be considerable if the side-plate clearance is less than the radial clearance. As the side-plate clearance reduces towards zero, the effectiveness of the squeeze film damper diminishes until the amplitudes obtained are the same as those measured when the rolling-contact bearing is rigidly supported. An interesting type of precessing elliptical orbit was discovered for conditions where the “jump” phenomenon was operating.

Experimental Study on the Vibration Control Capability of a Hybrid Squeeze Film Damper

2001 ◽  
Author(s):  
Changsheng Zhu
Keyword(s):  
Dynamic Characteristics ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Flexible Rotor ◽  
Nonlinear Characteristics ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Hybrid Combination ◽  
Highly Nonlinear ◽  
Control Capability

In order to improve the highly nonlinear characteristics of the conventional hydrodynamic squeeze film damper (SFD) in high journal eccentricity ratios and make its dynamic characteristics controllable, a hybrid (combination hydrostatic and hydrodynamic) squeeze film damper (HSFD) is presented. The effectiveness of the hybrid squeeze film damper in attenuating vibration of rotor systems and in improving the high non-linearity of oil film forces of the conventional hydrodynamic SFD is experimentally studied in this paper with a rigid rotor and a flexible rotor. The steady state unbalance responses of rotor-HSFD systems are compared with those of rotor-SFD systems in different radial clearance ratios. It is shown that the HSFD has very good linear dynamic characteristics and can effectively attenuate vibration of rotor systems, especially in larger rotor unbalances and large radial clearance ratios.

scholarly journals The Damping Capacity of a Sealed Squeeze Film Bearing

1985 ◽  
Vol 107 (3) ◽  
pp. 411-418 ◽  
Author(s):  
M. M. Dede ◽  
M. Dogan ◽  
R. Holmes
Keyword(s):  
Theoretical Model ◽  
Gas Turbine ◽  
Squeeze Film ◽  
Damping Capacity ◽  
Test Rig ◽  
Squeeze Film Damper ◽  
Aero Engine

The purpose of this paper is to establish a theoretical model to represent a sealed squeeze-film damper bearing and to assess it against results from a test rig, simulating the essential features of a medium-sized gas turbine aero engine.

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.

Dynamic Analysis of a Coupled Dual-Rotor With Squeeze Film Damper Considering Sudden Unbalance

2021 ◽  
Author(s):  
Ying Cui ◽  
Yuxi Huang ◽  
Guogang Yang ◽  
Yongliang Wang ◽  
Han Zhang
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Rotor System ◽  
Lubricating Oil ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Oil Viscosity ◽  
Squeeze Film Damper ◽  
Damping Effect ◽  
Bistable State

Abstract A nonlinear multi-degree-of-freedom dynamic model of a coupled dual-rotor system with an intershaft bearing and uncentralized squeeze film damper is established by using finite element method. Based on the model, the critical speed characteristic diagram and vibration modes of the system were calculated. The steady-state unbalance response is obtained by using Newmark-β algorithm. The numerical results show the effect of SFD position in the dual-rotor system on response amplitude. It is found that with the decrease of radial clearance and the increase of length-diameter ratio and lubricating oil viscosity, the damping effect of SFD is enhanced and the bistable state phenomenon can be suppressed. The transient response of the system in case of sudden unbalance occurring at the fan was simulated by applying a step function. It is demonstrated that the SFD can effectively reduce the duration and maximum amplitude of the transient process, but at certain speeds, the SFD will increase the amplitude after the system returns to steady state, the damping effect on the transient response is also enhanced with the increase of length-diameter and the decrease of radial clearance, and with the increase of the sudden unbalance value, the response is more likely to stabilized at the high amplitude state of the bistable state.

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.

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