The Effect of Squeeze Film Damper Parameters on the Unbalance Response and Stability of a Flexible Rotor

1998 ◽  
Vol 120 (1) ◽  
pp. 140-148 ◽  
Author(s):  
F. Chu ◽  
R. Holmes
Keyword(s):  
Research Work ◽  
Stability Control ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Squeeze Film Damper ◽  
Significant Movement ◽  
Squeeze Film Dampers ◽  
Bearing Assembly ◽  
Static Eccentricity ◽  
Points Of View

There has been much research work carried out on various aspects of individual squeeze-film dampers (SFDs) but very little on the interplay between a damper and the rotating assembly of which it forms a part. In this paper, a flexible rotor-bearing assembly in a configuration, typical of a small centrifugal pump and incorporating an SFD, is investigated theoretically and experimentally from the points of view of forced vibration control and stability control. It is found that change in rotor unbalance, SFD static eccentricity ratio, and SFD supply pressure can cause significant movement of system resonances and vibration resulting from excessive damping. The provision of an SFD also delays the onset of instability and because of its nonlinearity, the SFD contributes more damping than can a linear damper when the vibration amplitude becomes large as instability develops. It is shown that this instability is curbed at some limit cycle, whose frequency is a system natural frequency.

scholarly journals The Effect of Squeeze Film Damper Parameters on the Unbalance Response and Stability of a Flexible Rotor

1996 ◽  
Author(s):  
F. Chu ◽  
R. Holmes
Keyword(s):  
Research Work ◽  
Stability Control ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Squeeze Film Damper ◽  
Significant Movement ◽  
Squeeze Film Dampers ◽  
Bearing Assembly ◽  
Static Eccentricity ◽  
Points Of View

There has been much research work carried out on various aspects of individual squeeze-film dampers (SFDs) but very little on the interplay between a damper and the rotating assembly of which it forms a part. In this paper, a flexible rotor-bearing assembly in a configuration, typical of a small centrifugal pump and incorporating an SFD is investigated theoretically and experimentally from the points of view of forced vibration control and stability control. It is found that change in rotor unbalance, SFD static eccentricity ratio and SFD supply pressure can cause significant movement of system resonances and vibration resulting from excessive damping. The provision of an SFD also delays the onset of instability and because of its nonlinearity, the SFD contributes more damping than can a linear damper when the vibration amplitude becomes large as instability develops. It is shown that this instability is curbed at some limit cycle, whose frequency is a system natural frequency.

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.

A Study of the Influence of Static Eccentricity and Unbalance on Cavitation Effects in a Squeeze Film Damped Flexible Rotor

2002 ◽  
Author(s):  
Philip Bonello ◽  
Michael J. Brennan ◽  
Roy Holmes
Keyword(s):  
Dynamic Systems ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Test Rig ◽  
Squeeze Film Damper ◽  
Static Eccentricity ◽  
Rotor Dynamic ◽  
Rigid Rotors

The study of eccentric squeeze film damped rotor dynamic systems has largely concentrated on rigid rotors. In this paper, a newly developed receptance harmonic balance method is used to efficiently analyze a squeeze film damped flexible rotor test rig. The aim of the study is to investigate the influence of damper static eccentricity and unbalance level on cavitation and its resulting effect on the vibration level. By comparing predictions for the rotor vibration levels obtained respectively with, and without, lower pressure limits for the eccentric squeeze film damper model, it is demonstrated that cavitation is promoted by increasing static eccentricity and/or unbalance level. This, in turn, is found to have a profound effect on the predictions for the critical vibration levels, which such dampers are designed to attenuate. The reported findings are backed by experimental evidence from the test rig.

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.

Reduced-order modelling methods to assess the overall vibration response of a flexible rotor-squeeze film damper bearing assembly

2002 ◽  
Vol 216 (11) ◽  
pp. 1081-1097
Author(s):  
C C Siew ◽  
M Hill ◽  
R Holmes ◽  
M J Brennan
Keyword(s):  
Computing Time ◽  
Three Dimensional ◽  
Vibration Response ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Reduced Order ◽  
Squeeze Film Damper ◽  
Bearing Assembly ◽  
Reduced Order Methods

This paper uses two reduced-order methods to calculate the overall non-linear vibration response of a multi-mode rotor-squeeze film damper (SFD) bearing assembly. Good agreement has been found between their computed results and those calculated by the conventional Runge-Kutta-Merson method (RKMM), yet they require less than 5 per cent of the computing time consumed by the RKMM. They are applied to compute the vibration response, three-dimensional deflection shape and the overall vibrational kinetic energy of the rotor-bearing assembly. The assembly is simulated under various operating conditions including different unbalances, oil viscosities, static misalignments and damper factors. It is concluded that effective vibration control of a flexible rotor-SFD bearing assembly can be achieved when the vertical static eccentricity ratio of the SFD is set to a certain limit.

The influence of fluid inertia forces on the sudden unbalance responses of squeeze-film damper supported rotors

1998 ◽  
Vol 212 (5) ◽  
pp. 353-357 ◽  
Author(s):  
G Meng ◽  
Y-C Guo ◽  
E. J. Hahn
Keyword(s):  
Transient Process ◽  
Vibration Amplitude ◽  
Constant Speed ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Fluid Inertia ◽  
Transient Vibration ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Inertia Forces

The influence of fluid inertia on the sudden unbalance response of a flexible rotor supported on centralized and uncentralized squeeze-film dampers is investigated. Whether the rotor is at constant speed or accelerating, it was generally found that fluid inertia shortens the transient process and decreases the transient vibration amplitude. Qualitatively, the effect of fluid inertia is similar to increased damping.

A Study of the Nonlinear Interaction Between an Eccentric Squeeze Film Damper and an Unbalanced Flexible Rotor

2004 ◽  
Vol 126 (4) ◽  
pp. 855-866 ◽  
Author(s):  
Philip Bonello ◽  
Michael J. Brennan ◽  
Roy Holmes
Keyword(s):  
Periodic Solutions ◽  
Nonlinear Interaction ◽  
Harmonic Balance ◽  
Linear Part ◽  
Harmonic Balance Method ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Test Rig ◽  
Squeeze Film Damper ◽  
Static Eccentricity

In this paper, the nonlinear interaction between an eccentric squeeze film damper and an unbalanced flexible rotor is investigated, paying particular attention to the effect of cavitation in the damper. A harmonic balance method that uses the receptance functions of the rotating linear part of the system to determine periodic solutions to the nonlinear problem is used to predict vibration levels in a test rig. By comparing predictions obtained respectively with, and without, lower pressure limits for the squeeze film damper model, it is concluded that cavitation is promoted by increasing static eccentricity and/or unbalance level. This, in turn, is found to have a profound effect on the predictions for the critical vibration levels, which such dampers are designed to attenuate. Experimental results are presented to support the findings.

Determination of Damping Coefficient of a Bump Foil Squeeze Film Damper

2017 ◽  
Vol 8 (4) ◽  
Author(s):  
G. Saravanakumar ◽  
L. Ravikumar ◽  
R. Yogaraju ◽  
C. Shravankumar ◽  
V. Arunkumar
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Research Work ◽  
Squeeze Film ◽  
Jet Engines ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Magneto Rheological ◽  
Temperature Dynamic

The present investigation is aiming to get better squeeze film dampers which are normally used in high speed jet engines to minimize small amplitude large force vibrations. The investigation was started with squeeze film dampers employing conventional lubricating oils. Magneto rheological fluids are then used to enhance the viscosity characteristics of the fluid under the influence of magnetic fields in order to improve the damper performances. It is observed that the dynamic characteristics of the damper with magneto rheological fluids are enhanced. Further to improve the damper performance, few modifications in the damper assembly are carried out in this research work. A good amount of reduction in the amplitude of vibrations is observed in these modified squeeze film dampers coupled with magneto rheological fluids. This research work discusses dual and triple clearance squeeze film dampers and bump foil squeeze film damper, also subjected to variation in temperature. Dynamic characteristics are found to be decreasing as the viscosity of the fluid decreases with rise in temperature of the fluid.

scholarly journals A computational fluid dynamics investigation of the segmented integral squeeze film damper

2019 ◽  
Vol 254 ◽  
pp. 08005 ◽  
Author(s):  
Petr Ferfecki ◽  
Jaroslav Zapoměl ◽  
Marek Gebauer ◽  
Václav Polreich ◽  
Jiří Křenek
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Ansys Cfx ◽  
Squeeze Film Dampers ◽  
Tilting Pad ◽  
Vibration Attenuation ◽  
Tilting Pad Journal Bearing

Rotor vibration attenuation is achieved with damping devices which work on different, often mutually coupled, physical principles. Squeeze film dampers are damping devices that have been widely used in rotordynamic applications. A new concept of a 5-segmented integral squeeze film damper, in which a flexure pivot tilting pad journal bearing is integrated, was investigated. The damper is studied for the eccentric position between the outer and inner ring of the squeeze film land. The ANSYS CFX software was used for solving the pressure and velocity distribution. The development of the complex three-dimensional computational fluid dynamics model of the squeeze film damper, learning more about the effect of the forces in the damper, and the knowledge about the behaviour of the flow are the principal contributions of this article.

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