Squeeze film dampers supporting high-speed rotors: Fluid inertia effects

2019 ◽  
Vol 234 (1) ◽  
pp. 18-32 ◽  
Author(s):  
Sina Hamzehlouia ◽  
Kamran Behdinan
Keyword(s):  
Thin Film ◽  
Pressure Distribution ◽  
Closed Form ◽  
Hydrodynamic Pressure ◽  
Fluid Film ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Thin Film Equations ◽  
Squeeze Film Dampers ◽  
Reaction Forces

This work represents closed-form analytical expressions for the operating parameters for short-length open-ended squeeze film dampers, including the lubricant velocity profiles, hydrodynamic pressure distribution, and lubricant reaction forces. The proposed closed-form expressions provide an accelerated calculation of the squeeze film damper parameters, specifically for rotordynamics applications. In order to determine the analytical solutions for the squeeze film damper parameters, the thin film equations for lubricant are introduced in the presence of the influence of lubricant inertia. Subsequently, two different analytical techniques, namely the momentum approximation method, and the perturbation method are applied to the thin film equations. Moreover, the solution for the lubricant flow equations are analytically determined to represent closed-form expressions for the hydrodynamic pressure distribution and the velocity component profiles in squeeze film dampers. Additionally, the expressions for the hydrodynamic pressure distribution are integrated over the journal surface, either numerically or analytically by using Booker’s integrals, to develop expressions for the fluid film reaction forces. Lastly, the developed squeeze film damper models are incorporated into simulation models in Matlab and Simulink®, and the results are compared against a well-established force coefficient model to verify the accuracy of the calculations. The results of the simulations verify the effect of the lubricant inertia components, namely the convective and temporal (i.e., unsteady) inertia components on the squeeze film damper dynamics, including hydrodynamic pressure distribution and fluid film reaction forces. Additionally, the simulation results suggest a close agreement between the proposed models and the results in the literature.

scholarly journals Squeeze Film Dampers Executing Small Amplitude Circular-Centered Orbits in High-Speed Turbomachinery

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Sina Hamzehlouia ◽  
Kamran Behdinan
Keyword(s):  
Pressure Distribution ◽  
Small Amplitude ◽  
High Speed ◽  
Fluid Film ◽  
Distribution Model ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Squeeze Film Dampers ◽  
Reaction Forces

This work represents a pressure distribution model for finite length squeeze film dampers (SFDs) executing small amplitude circular-centered orbits (CCOs) with application in high-speed turbomachinery design. The proposed pressure distribution model only accounts for unsteady (temporal) inertia terms, since based on order of magnitude analysis, for small amplitude motions of the journal center, the effect of convective inertia is negligible relative to unsteady (temporal) inertia. In this work, the continuity equation and the momentum transport equations for incompressible lubricants are reduced by assuming that the shapes of the fluid velocity profiles are not strongly influenced by the inertia forces, obtaining an extended form of Reynolds equation for the hydrodynamic pressure distribution that accounts for fluid inertia effects. Furthermore, a numerical procedure is represented to discretize the model equations by applying finite difference approximation (FDA) and to numerically determine the pressure distribution and fluid film reaction forces in SFDs with significant accuracy. Finally, the proposed model is incorporated into a simulation model and the results are compared against existing SFD models. Based on the simulation results, the pressure distribution and fluid film reaction forces are significantly influenced by fluid inertia effects even at small and moderate Reynolds numbers.

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.

scholarly journals Squeeze-Film Damper Technology: Part 1 — Prediction of Finite Length Damper Performance

1983 ◽  
Author(s):  
J. W. Lund ◽  
A. J. Smalley ◽  
J. A. Tecza ◽  
J. F. Walton
Keyword(s):  
Finite Length ◽  
Gas Turbines ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Strongly Coupled ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Squeeze Film Dampers ◽  
Calculation Results

Squeeze-film dampers are commonly used in gas turbine engines and have been applied successfully in a great many new designs, and also as retrofits to older engines. Of the mechanical components in gas turbines, squeeze-film dampers are the least understood. Their behavior is nonlinear and strongly coupled to the dynamics of the rotor systems on which they are installed. The design of these dampers is still largely empirical, although they have been the subject of a large number of past investigations. To describe recent analytical and experimental work in squeeze-film damper technology, two papers are planned. This abstract outlines the first paper, Part 1, which concerns itself with squeeze-film damper analysis. This paper will describe an analysis method and boundary conditions which have been developed recently for modelling dampers, and in particular, will cover the treatment of finite length, feed and drain holes and fluid inertia effects, the latter having been shown recently to be of great importance in predicting rotor system behavior. A computer program that solves the Reynolds equation for the above conditions will be described and sample calculation results presented.

Inertia Effects in Squeeze-Film Damper Bearings Generated by Circumferential Oil Supply Groove

2001 ◽  
Author(s):  
Jørgen W. Lund ◽  
Claus M. Myllerup ◽  
Henning Hartmann
Keyword(s):  
Dynamic Properties ◽  
Bulk Flow ◽  
Squeeze Film ◽  
Perturbation Approach ◽  
Inertia Effects ◽  
Squeeze Film Damper ◽  
Oil Supply ◽  
Reaction Forces ◽  
Flow Approximation ◽  
Acceleration Term

Abstract The dynamic properties of an industrial Squeeze-Film Damper (SFD) bearing design are described using the well-known perturbation approach, where the reaction forces induced by small movements away from the position of equilibrium are expanded into a Taylor series in terms of displacement, velocity, and acceleration. Although generally negligible, the acceleration term can become significant in SFD bearings when inertia effects in the damper lands are enhanced by the flow in a central circumferential oil supply groove. By using a bulk flow approximation in the oil supply groove an explicit expression is derived for the acceleration term. Experimental results confirm the significance of the oil supply groove geometry and appear to validate the bulk flow approximation.

CFD Simulation of Air Ingestion in a Squeeze Film Damper

2019 ◽  
Author(s):  
Wang Yan ◽  
Li Xuesong ◽  
Li Yuhong
Keyword(s):  
High Performance ◽  
Cfd Simulation ◽  
Pressure Effect ◽  
Hydrodynamic Pressure ◽  
Squeeze Film ◽  
Rotor Vibration ◽  
Squeeze Film Damper ◽  
Bearing Clearance ◽  
Oil Flow ◽  
Computational Fluid Dynamics Cfd

Abstract Squeeze film damper (SFD) is widely adopted in the high performance rotor-bearing systems to eliminate rotor vibration and improve stability. Experiments show that the air ingestion from the open end would have notable impact on the SFD performance. Multiphase Computational Fluid Dynamics (CFD) calculation on the air ingestion in the SFD is conducted in this work. Results are validated with the experimental data to prove the capability of the multiphase CFD on predicting the air ingestion. Air and oil flow in the SFD are analyzed in details. By comparing the CFD results with and without air ingestion, the effect of air ingestion is revealed. Results show that CFD is capable of predicting the air-oil flow in the SFD. The maximum air region is located in the vicinity of the largest bearing clearance region rather than the low pressure zone. And air ingestion in the largest bearing clearance region counteracts the hydrodynamic pressure effect in the vicinity.

Application of CFD Analysis for Rotating Machinery: Part 1 — Hydrodynamic, Hydrostatic Bearings and Squeeze Film Damper

2003 ◽  
Author(s):  
Zenglin Guo ◽  
Toshio Hirano ◽  
R. Gordon Kirk
Keyword(s):  
Traditional Method ◽  
Reasonable Agreement ◽  
Pressure Field ◽  
Squeeze Film ◽  
Cfd Analysis ◽  
Complex Flow ◽  
Static And Dynamic Characteristics ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Machinery Part

The traditional method for bearing and damper analysis usually involves a development of rather complicated numerical calculation programs that may just focus on a simplified and specific physical model. The application of the general CFD codes may make this analysis available and effective where complex flow geometries are involved or when more detailed solutions are needed. In this study, CFX-TASCflow is employed to simulate various fixed geometry fluid-film bearing and damper designs. Some of the capabilities in CFX-TASCflow are applied to simulate the pressure field and calculate the static and dynamic characteristics of hydrodynamic, hydrostatic and hybrid bearings as well as squeeze film dampers. The comparison between the CFD analysis and current computer programs used in industry has been made. The results show reasonable agreement in general. Some of possible reasons for the differences are discussed. It leaves room for further investigation and improvement on the methods of computation.

Application of CFD Analysis for Rotating Machinery—Part I: Hydrodynamic, Hydrostatic Bearings and Squeeze Film Damper

2005 ◽  
Vol 127 (2) ◽  
pp. 445-451 ◽  
Author(s):  
Zenglin Guo ◽  
Toshio Hirano ◽  
R. Gordon Kirk
Keyword(s):  
Traditional Method ◽  
Reasonable Agreement ◽  
Pressure Field ◽  
Squeeze Film ◽  
Cfd Analysis ◽  
Complex Flow ◽  
Static And Dynamic Characteristics ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Machinery Part

The traditional method for bearing and damper analysis usually involves a development of rather complicated numerical calculation programs that may just focus on a simplified and specific physical model. The application of the general CFD codes may make this analysis available and effective where complex flow geometries are involved or when more detailed solutions are needed. In this study, CFX-TASCflow is employed to simulate various fixed geometry fluid-film bearing and damper designs. Some of the capabilities in CFX-TASCflow are applied to simulate the pressure field and calculate the static and dynamic characteristics of hydrodynamic, hydrostatic, and hybrid bearings as well as squeeze film dampers. The comparison between the CFD analysis and current computer programs used in industry has been made. The results show reasonable agreement in general. Some of the possible reasons for the differences are discussed. It leaves room for further investigation and improvement on the methods of computation.

scholarly journals Elastomer Damper Performance: A Comparison With a Squeeze Film for a Supercritical Power Transmission Shaft

1980 ◽  
Author(s):  
E. S. Zorzi ◽  
G. Burgess ◽  
R. Cunningham
Keyword(s):  
Critical Power ◽  
Power Transmission ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Operating Range ◽  
Transmission Shaft ◽  
Bending Mode ◽  
Squeeze Film Dampers ◽  
Design And Testing

This paper describes the design and testing of an elastomer damper on a super-critical power transmission shaft. The elastomers were designed to provide acceptable operation through the fourth bending mode and to control synchronous as well as nonsynchronous vibration throughout the operating range. The design of the elastomer was such that it could be incorporated into the system as a replacement for a squeeze-film damper without a reassembly, which could have altered the imbalance of the shaft. This provided a direct comparison of the elastomer and squeeze-film dampers without having to assess the effect of shaft imbalance changes.

The Control of Engine Vibration Using Squeeze Film Dampers

1983 ◽  
Vol 105 (3) ◽  
pp. 525-529 ◽  
Author(s):  
R. Holmes
Keyword(s):  
Experimental Work ◽  
Squeeze Film ◽  
Vibration Isolator ◽  
Squeeze Film Damper ◽  
Engine Vibration ◽  
Transmitted Force ◽  
Squeeze Film Dampers ◽  
Jump Phenomena ◽  
Theoretical Predictions ◽  
In Series

This paper describes the following roles of a squeeze-film damper when used in gas turbine applications as a means of reducing vibration and transmitted force due to unbalance: (a) as an element in parallel with a soft spring in a vibration isolator; and (b) as an element in series with the stiffness of the engine pedestal. The effects of cavitation on performance are elucidated, and the dangers of jump phenomena and subsynchronous response are discussed. Experimental work is described in which both roles of the squeeze-film damper are investigated and the results are compared with theoretical predictions.

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.

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