Compliant Hybrid Gas Bearing Using Modular Hermetically Sealed Squeeze Film Dampers

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Bugra Ertas ◽  
Adolfo Delgado
Keyword(s):  
High Speed ◽  
Experimental Testing ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Component Testing ◽  
High Speeds ◽  
Squeeze Film Dampers ◽  
Support Force ◽  
Bearing Design ◽  
Gas Bearing

This paper presents a new gas bearing concept that targets machine applications in the megawatt (MW) power range. The concept involves combining a compliant hybrid gas bearing (CHGB) with two hermetically sealed squeeze film damper (HSFD) modules installed in the bearing support damper cavities. The main aim of the research was to demonstrate gas bearing-support damping levels using HSFD that rival conventional open-flow squeeze film dampers (SFD) in industry. A detailed description of the bearing design and functionality is discussed while anchoring the concept through a brief recap of past gas bearing concepts. Proof-of-concept experimental testing is presented involving parameter identification of the bearing support force coefficients along with a demonstration of speed and load capability using recessed hydrostatic pads. Finally, a landing test was performed on the bearing at high speed and load with porous carbon pads to show capability of sustaining rubs at high speeds. The component testing revealed robust viscous damping in the bearing support, which was shown to be comparable to existing state of the art SFD concepts. The damping and stiffness of the system-portrayed moderate frequency dependency, which was simulated using a 2D Reynolds-based incompressible fluid flow model. Finally, rotating tests demonstrated the ability of the gas bearing concept to sustain journal excursions and loads indicative of critical speed transitions experienced in large turbomachinery.

Compliant Hybrid Gas Bearing Using Modular Hermetically-Sealed Squeeze Film Dampers

2018 ◽  
Author(s):  
Bugra Ertas ◽  
Adolfo Delgado
Keyword(s):  
High Speed ◽  
Experimental Testing ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Component Testing ◽  
High Speeds ◽  
Squeeze Film Dampers ◽  
Support Force ◽  
Bearing Design ◽  
Gas Bearing

The following paper presents a new gas bearing concept that targets machine applications in the megawatt (MW) power range. The concept involves combining a compliant hybrid gas bearing (CHGB) with 2 hermetically sealed squeeze film damper (HSFD) modules installed in the bearing support damper cavities. The main aim of the research was to demonstrate gas bearing-support damping levels using HSFD that rival conventional open-flow squeeze film dampers (SFD) in industry. A detailed description of the bearing design and functionality is discussed while anchoring the concept through a brief recap of past gas bearing concepts. Proof-of-concept experimental testing is presented involving parameter identification of the bearing support force coefficients along with a demonstration of speed and load capability using recessed hydrostatic pads. Lastly, a landing test was performed on the bearing at high speed and load with porous carbon pads to show capability of sustaining rubs at high speeds. The component testing revealed robust viscous damping in the bearing support, which was shown to be comparable to existing state of the art SFD concepts. The damping and stiffness of the system portrayed moderate frequency dependency, which was simulated using a 2D Reynolds based incompressible fluid flow model. Lastly, rotating tests demonstrated the ability of the gas bearing concept to sustain journal excursions and loads indicative of critical speed transitions experienced in large turbomachinery.

Compliant Hybrid Gas Bearing Using Integral Hermetically Sealed Squeeze Film Dampers

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Bugra Ertas
Keyword(s):  
Squeeze Film ◽  
Force Coefficients ◽  
Overall Design ◽  
Single Piece ◽  
Squeeze Film Dampers ◽  
Tilting Pad ◽  
Support Force ◽  
Bearing Design ◽  
Gas Bearing ◽  
Gaining Insight

AbstractThis paper focuses on an integral gas-film lubricated bearing concept developed to enable the oil-free operation of super-critical carbon dioxide (sCO2) turbomachinery. The externally pressurized tilting pad bearing concept possesses a flexible bearing support with an integral hermetically sealed squeeze film damper. Unlike the past concepts using modular hermetic squeeze film dampers presented, the bearing design in this work utilizes advanced manufacturing methods to yield an integral single piece design in efforts to reduce space envelope, cost, and improve overall design reliability. The paper advances a detailed description of the bearing design and identification of bearing support force coefficients. Nonrotating benchtop tests show the influence of vibration amplitude, frequency, and damper cavity pressurization on force coefficients for two different viscosity fluids. Results indicate an increase in stiffness and a decrease in damping when increasing the frequency of excitation. Damper cavity pressurization was shown to eliminate squeeze film cavitation for the vibration amplitudes and frequency range in the study. Additionally, the paper advances a transient fluid–structure interaction (FSI) analysis aimed at gaining insight on the interaction of flexible elements bounding a hermetic fluid volume experiencing sinusoidal vibratory motion. The analysis considers an idealized damper model with and without a vibration transmission post while varying diaphragm modulus of elasticity for three excitation frequencies. Computational results were able to capture the increase in stiffness and the decrease in damping and show that the flexibility of the bounding elements influence the damper cavity volume change and phase ultimately affecting dynamic cavity pressures and force coefficients.

Compliant Hybrid Gas Bearing Using Integral Hermetically-Sealed Squeeze Film Dampers

2019 ◽  
Author(s):  
Bugra Ertas
Keyword(s):  
Past Research ◽  
Squeeze Film ◽  
Force Coefficients ◽  
Overall Design ◽  
Single Piece ◽  
Squeeze Film Dampers ◽  
Tilting Pad ◽  
Support Force ◽  
Bearing Design ◽  
Gas Bearing

Abstract The following paper focuses on an integral gas-film lubricated bearing concept developed to enable the oil-free operation of super-critical carbon dioxide (sCO2) turbomachinery. The externally pressurized tilting pad bearing concept possesses a flexible bearing support with an integral hermetically sealed squeeze film damper. Unlike the initial concepts using modular hermetic squeeze film dampers presented in past research, the bearing design in this work utilizes advanced manufacturing methods to yield an integral single piece design developed to reduce space envelope, cost, and improved overall design reliability. The paper advances a detailed description of the bearing design and identification of bearing support force coefficients. Non-rotating bearing support test results show the influence of vibration amplitude, frequency, and damper cavity pressurization on force coefficients for two different viscosity fluids. Results indicate an increase in stiffness and a decrease in damping when increasing the frequency of excitation. Damper cavity pressurization was shown to eliminate squeeze film cavitation for the vibration amplitudes and frequency range in the study. Additionally, the paper advances a transient fluid-structure interaction (FSI) analysis aimed at gaining insight on the interaction of flexible elements bounding a hermetic fluid volume experiencing sinusoidal vibratory motion. The analysis considers an idealized damper model with and without a vibration transmission post while varying diaphragm modulus of elasticity for three excitation frequencies. Computational results were able to capture the increase in stiffness and decrease in damping and show that the flexibility of the bounding elements influence the damper cavity volume change and phase; ultimately effecting dynamic cavity pressures and force coefficients.

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.

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.

Effects of Adding a Central Groove to the Squeeze Film Damper Lands

2013 ◽  
Author(s):  
Praneetha Boppa ◽  
Aarthi Sekaran ◽  
Gerald Morrison
Keyword(s):  
Vibration Amplitude ◽  
High Speed ◽  
Dynamic Pressure ◽  
Aerospace Industry ◽  
Squeeze Film ◽  
Structural Components ◽  
Squeeze Film Damper ◽  
Pressure Profiles ◽  
Squeeze Film Dampers ◽  
Bearing System

Squeeze film dampers (SFDs) are used in the high speed turbo machinery industry and aerospace industry as a means to reduce vibration amplitude, to provide damping, to improve dynamic stability of the rotor bearing system and to isolate structural components. Past studies have not included effects of variation of the stator geometries in a squeeze film damper. A central groove added to the squeeze film land is hypothesized to provide a uniform flow source which theory predicts will result in forces less than one fourth of that seen in SFDs without a central groove. In the present study, 3D numerical simulations of SFDs with different size central grooves on the squeeze film land are performed to predict the variation of the dynamic pressure profiles. The numerical model and method have been validated via comparison to experimental data for a SFD without a central groove. When a central groove is added to the squeeze film land, the pressures generated are reduced to half of that generated when run without a central groove on the land. The amount of reduction in pressure values depends on the volume of the groove, not on the aspect ratio of the groove. Addition of a central groove reduces the pressures, rigidity developed in squeeze film land, and forces generated by squeeze film damper.

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.

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.

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.

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