A Dynamic Analysis of a Dual Clearance Squeeze Film Damper

2010 ◽  
Author(s):  
L. Moraru ◽  
T. G. Keith ◽  
F. Dimofte ◽  
S. Cioc ◽  
N. Ene ◽  
...  
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Numerical Solutions ◽  
Rotating Machinery ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Abnormal Operating Conditions ◽  
Oil Films

Squeeze film dampers (SFD) are devices utilized to control the shafts of high-speed rotating machinery. A dual squeeze film damper (DSFD) consists of two squeeze film bearings that are separated by a sleeve, which is released when the rotor experiences abnormal operating conditions. In this part of our study of DSFD we analyze the case when both the inner and the outer oil films are active. We present computed and measured unbalance responses of a shaft supported in DSFD. The oil forces which are utilized in the calculation of the unbalance response are obtained from numerical solutions of the Reynolds equation. A finite-difference algorithm is utilized for solving the pressure equation within the calculation of the dynamic response of the shaft.

Dynamic Modeling of a Dual Clearance Squeeze Film Damper: Part III

2005 ◽  
Author(s):  
L. Moraru ◽  
F. Dimofte ◽  
S. Cioc ◽  
T. G. Keith ◽  
D. P. Fleming
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Rotating Machinery ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Squirrel Cage ◽  
Squeeze Film Dampers ◽  
Abnormal Operating Conditions ◽  
Oil Films

Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. A dual squeeze film damper (DSFD) consists of two squeeze film bearings that are separated by a sleeve, which is released when the rotor experiences abnormal operating conditions. In this part of our study of DSFD we analyze the case when both the inner and the outer oil films are active and the separating sleeve is supported by a squirrel cage. Numerical results are compared with the experimental data.

A Study of a Dual Clearance Squeeze Film Damper

2009 ◽  
Author(s):  
L. Moraru ◽  
T. G. Keith ◽  
F. Dimofte ◽  
S. Cioc ◽  
D. P. Fleming
Keyword(s):  
High Speed ◽  
Numerical Solutions ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Pressure Distributions ◽  
Squeeze Film Dampers ◽  
Abnormal Operating Conditions ◽  
Oil Films ◽  
Analytical Expressions

Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. A dual squeeze film damper (DSFD) consists of two squeeze film bearings that are separated by a sleeve, which is released when the rotor experiences abnormal operating conditions. In this part of our study of DSFD we analyze the case when both the inner and the outer oil films are active. Previous studies utilized closed form analytical expressions to describe the forces within the lubricant. In this paper the oil forces are modeled using pressure distributions obtained from numerical solutions of the Reynolds equation. Numerical results are compared with the experimental data.

Experimental and Analytical Investigation of Hybrid Squeeze Film Dampers

1993 ◽  
Vol 115 (2) ◽  
pp. 353-359 ◽  
Author(s):  
A. El-Shafei
Keyword(s):  
High Speed ◽  
Extreme Case ◽  
Analytical Investigation ◽  
Rotating Machinery ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Controlling Mechanism ◽  
Squeeze Film Dampers ◽  
Oil Flow ◽  
Hybrid Damper

A new concept for actively controlling high-speed rotating machinery is investigated both analyically and experimentally. The controlling mechanism consists of a hybrid squeeze film damper (patent pending) that can be adaptively controlled to change its characteristics according to the instructions of a controller. In an extreme case the hybrid damper can act as a long damper, which is shown to be effective in reducing the amplitude of vibration of rotating machinery. In the other extreme the hybrid damper acts as a short damper, which is shown to be effective in reducing the force transmitted to the support. In the long damper configuration the oil flow is circumferential, while in the short damper configuration the oil flow is predominantly axial. The hybrid damper is designed to operate in either the short or the long damper configuration by controlling the positions of two movable sealing rings. The hybrid damper was tested on a Bently Nevada Rotor Kit and it is shown experimentally that the long damper configuration is extremely efficient at controlling the amplitude of vibration and the short damper configuration reduces the force transmitted to the support.

Time Transient Analysis of Horizontal Rigid Rotor Supported With O-Ring Sealed Squeeze Film Damper

2013 ◽  
Author(s):  
Saeid Dousti ◽  
Timothy W. Dimond ◽  
Paul E. Allaire ◽  
Houston E. Wood
Keyword(s):  
Transient Analysis ◽  
Reynolds Equation ◽  
Equations Of Motion ◽  
Excitation Frequency ◽  
Numerical Data ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Rigid Rotor ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers

This study addresses the nonlinear dynamic behavior of O-ring seals as the retaining spring in squeeze film dampers (SFDs). An analytical model is developed to predict the restoring and hysteresis forces of elastomer O-rings based on experimental and numerical data. This model takes into account the temperature softening and excitation frequency hardening effects in O-rings as well as the installation conditions in the form of radial and vertical preloads, σ and γ, respectively. Long bearing assumption is adopted for the solution of Reynolds equation. The equations of motion of horizontal unbalanced rigid rotor are derived, and a dimensional analysis is conducted on them. The numerical results substantiates the synchronizing effects of bearing parameter, B and vertical preload, γ, and the asynchronizing effects of O-ring parameter, O and radial preload, σ. It is shown that the variation of temperature and rotational speed as operating conditions influence the rotor response significantly.

scholarly journals Experimental and Analytical Investigation of Hybrid Squeeze Film Dampers

1991 ◽  
Author(s):  
A. El-Shafei
Keyword(s):  
High Speed ◽  
Extreme Case ◽  
Analytical Investigation ◽  
Rotating Machinery ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Controlling Mechanism ◽  
Squeeze Film Dampers ◽  
Oil Flow ◽  
Hybrid Damper

A new concept for actively controlling high speed rotating machinery is investigated both analytically and experimentally. The controlling mechanism consists of a hybrid squeeze film damper (patent pending) that can be adaptively controlled to change its characteristics according to the instructions of a controller. In an extreme case the hybrid damper can act as a long damper which is shown to be effective in reducing the amplitude of vibration of rotating machinery. In the other extreme the hybrid damper acts as a short damper which is shown to be effective in reducing the force transmitted to the support. In the long damper configuration the oil flow is circumferential, while in the short damper configuration the oil flow is predominantly axial. The hybrid damper is designed to operate in either of the short or the long damper configurations by controlling the positions of two movable sealing rings. The hybrid damper was tested on a Bently Nevada Rotor Kit and it is shown experimentally that the long damper configuration is extremely efficient at controlling the amplitude of vibration and the short damper configuration reduces the force transmitted to the support.

Squeeze Film Damper Characteristics for Gas Turbine Engines

1978 ◽  
Vol 100 (1) ◽  
pp. 139-146 ◽  
Author(s):  
R. A. Marmol ◽  
J. M. Vance
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Matrix Inversion ◽  
Squeeze Film ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Squeeze Film Damper ◽  
Banded Matrix ◽  
Squeeze Film Dampers ◽  
Different Types

A mathematical model for squeeze film dampers is developed, and the solution results are compared with data from four different test rigs. A special feature of the analysis is the treatment of several different types of end seals and inlets, with inlet feedback included. A finite difference method is used to solve the Reynolds equation, with a banded matrix inversion routine. The test data are taken from a new high-speed free-rotor rig, and from three previously tested controlled-orbit rigs.

Application of computational fluid dynamics for thermohydrodynamic analysis of high-speed squeeze-film dampers

2019 ◽  
Vol 43 (3) ◽  
pp. 306-321 ◽  
Author(s):  
Maxime Perreault ◽  
Sina Hamzehlouia ◽  
Kamran Behdinan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Base Line ◽  
Squeeze Film Dampers ◽  
Shaft Deflection ◽  
Whirl Speed

In high-speed turbomachinery, the presence of rotor vibrations, which produce undesirable noise or shaft deflection and losses in performance, has brought up the need for the application of a proper mechanism to attenuate the vibration amplitudes. Squeeze-film dampers (SFDs) are a widely employed solution to the steady-state vibrations in high-speed turbomachinery. SFDs contain a thin film of lubricant that is susceptible to changes in temperature. For this reason, the analysis of thermohydrodynamic (THD) effects on the SFD damping properties is essential. This paper develops a computational fluid dynamics (CFD) model to analyze the THD effects in SFDs, and enabling the application of CFD analysis to be a base-line for validating the accuracy of analytical THD SFD models. Specifically, the CFD results are compared against numerical simulations at different operating conditions, including eccentricity ratios and journal whirl speeds. The comparisons demonstrate the effective application of CFD for THD analysis of SFDs. Additionally, the effect of the lubricant THDs on the viscosity, maximum and mass-averaged temperature, as well as heat generation rates inside the SFD lubricant are analyzed. The temperature of the lubricant is seen to rise with increasing whirl speed, eccentricity ratios, damper radial clearance, and shaft radii.

Design of Nonlinear Squeeze-Film Dampers for Aircraft Engines

1977 ◽  
Vol 99 (1) ◽  
pp. 57-64 ◽  
Author(s):  
E. J. Gunter ◽  
L. E. Barrett ◽  
P. E. Allaire
Keyword(s):  
Reynolds Equation ◽  
Nonlinear Effects ◽  
Aircraft Engine ◽  
Squeeze Film ◽  
Aircraft Engines ◽  
Transient Method ◽  
Squeeze Film Damper ◽  
Wide Range ◽  
Squeeze Film Dampers ◽  
Bearing Stiffness

This paper examines the effect of squeeze-film damper bearings on the steady state and transient unbalance response of aircraft engine rotors. The nonlinear effects of the damper are examined, and the variance of the motion due to unbalance, static pressurization, retainer springs, and rotor preload is shown. The nonlinear analysis is performed using a time-transient method incorporating a solution of the Reynolds equation at each instant in time. The analysis shows that excessive stiffness in the damper results in large journal amplitudes and transmission of bearing forces to the engine casing which greatly exceed the unbalance forces. Reduction of the total effective bearing stiffness through static pressurization and rotor preload is considered. The reduction in stiffness allows the damping generated by the bearing to be more effective in attenuating rotor forces. It is observed that in an unpressurized damper, the dynamic transmissibility will exceed unity when the unbalance eccentricity exceeds approximately 50 percent of the damper clearance for the relatively wide range of conditions examined in this study.

scholarly journals Analysis on Influences of Squeeze Film Damper on Vibrations of Rotor System in Aeroengine

2022 ◽  
Vol 12 (2) ◽  
pp. 615
Author(s):  
Haobo Wang ◽  
Yulai Zhao ◽  
Zhong Luo ◽  
Qingkai Han
Keyword(s):  
High Speed ◽  
Vibration Suppression ◽  
Rotor System ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Lumped Mass ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Vibration Responses ◽  
Stiffness And Damping

Squeeze film damper (SFD) is widely used in the vibration suppression of aeroengine rotor systems, but will cause complex motions of the rotor system under specific operating conditions. In this paper, a lumped-mass dynamic model of the high-pressure rotor system in an aeroengine is established, and the nonlinear stiffness and damping formula of SFD are introduced into the above model. The vibration responses of the rotor system under different rotating speeds and with different unbalances are investigated numerically, and the influence of SFD on the rotor system vibration and the change of suppression ability are compared and analyzed. The results show that in the case of high speed, together with a small unbalance, the rotor system will perform a complex vibration or a bistable vibration due to SFD. If the unbalance is properly increased under the same case of high speed, the vibration of the rotor becomes single-harmonic and the bistable vibration disappears. The research results can provide a helpful reference for analyzing complex vibration mechanisms of the rotor system with SFD and achieving an effective vibration suppression through unbalance regulation.

The Effect of Bistable Jump on the Reliability of Squeeze Film Damper

1991 ◽  
Author(s):  
Zhu Changsheng
Keyword(s):  
High Speed ◽  
Operating Time ◽  
Squeeze Film ◽  
Jump Phenomenon ◽  
Rotor Vibration ◽  
Squeeze Film Damper ◽  
Operation Speed ◽  
Squeeze Film Dampers ◽  
Speed Range ◽  
Pass Through

Abstract Based on lots of data from an experiment of a high-speed rotor supported on squeeze film dampers, this paper analyses that how the bistable jump affects the reliability of squeeze film dampers, if the rotor system has to frequently pass through the bistable oparation speed range. It is shown that the change of the rotor vibration amplitudes caused by times of passed through bistable operation speed range is more significant than that caused by steady operating time. The users must pay much attention to the bistable jump phenomenon in the successful application of squeeze film dampers.

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