Controllable Squeeze Film Damper (An Application of Electro-Rheological Fluid)

1992 ◽  
Vol 114 (3) ◽  
pp. 354-357 ◽  
Author(s):  
Shin Morishita ◽  
Jun’ichi Mitsui
Keyword(s):  
Apparent Viscosity ◽  
Vibration Mode ◽  
Squeeze Film ◽  
Damping Capacity ◽  
Flexible Rotor ◽  
Rotor Vibration ◽  
Squeeze Film Damper ◽  
Rotating Speed ◽  
Wide Range ◽  
Er Fluid

A notable characteristic of electro-rheological (ER) fluid is the variation of its apparent viscosity with the application of an electric field. The application of this characteristic to the performance of squeeze film damper of a flexible rotor is investigated in this paper. It is shown experimentally that by controlling the supporting damping capacity continuously, rotor vibration can be reduced remarkably a wide range of rotating speed. Moreover, the study indicates experimentally that there exists an optimum supporting damping for every vibration mode.

Controllable Squeeze Film Damper: An Application of Electro-Rheological Fluid

1991 ◽  
Author(s):  
Shin Morishita ◽  
Jun’ichi Mitsui
Keyword(s):  
Apparent Viscosity ◽  
Vibration Mode ◽  
Squeeze Film ◽  
Damping Capacity ◽  
Flexible Rotor ◽  
Rotor Vibration ◽  
Squeeze Film Damper ◽  
Rotating Speed ◽  
Wide Range ◽  
Er Fluid

Abstract A notable characteristic of Electro-Rheological (ER) fluid is the variation of its apparent viscosity with the application of an electric field. The application of this characteristic to the performance of squeeze film damper of a flexible rotor is investigated in this paper. It is shown experimentally that by controlling the supporting damping capacity continuously, rotor vibration can be reduced remarkably in a wide range of rotating speed. Moreover, the study indicates experimentally that there exists an optimum supporting damping for every vibration mode.

Directionally Controllable Squeeze Film Damper Using Electro-Rheological Fluid

2001 ◽  
Vol 124 (1) ◽  
pp. 105-109 ◽  
Author(s):  
Young Kong Ahn ◽  
Bo-Suk Yang ◽  
Shin Morishita
Keyword(s):  
Electric Field ◽  
Yield Stress ◽  
Apparent Viscosity ◽  
Rotor System ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Squeeze Film Damper ◽  
Er Fluid

Electro-Rheological (ER) fluid is a class of functional fluid whose yield stress can be changed by an electric field applied to the fluid, which is observed as a variation of apparent viscosity. This functional fluid is applied to a controllable squeeze film damper (SFD) for stabilizing a flexible rotor system. In applying ER fluid to a conventional passive SFD, a pair of rings in the damper can be used as electrodes. When the electrodes are divided into a horizontal pair and a vertical one, the SFD can provide external damping in each direction independently. A prototype of the directionally controllable SFD was constructed and its performance was experimentally and numerically investigated in the present work.

scholarly journals ER Fluid Squeeze Film Damper for Semi-Active Vibration Control Device: A Parametric Study

1995 ◽  
Author(s):  
Shin Morishita ◽  
Young Kong An ◽  
Jun’ichi Mitsui
Keyword(s):  
Electric Field ◽  
Colloidal Suspension ◽  
Scale Model ◽  
Squeeze Film ◽  
Small Scale ◽  
Flexible Rotor ◽  
Squeeze Film Damper ◽  
Rotating Speed ◽  
Flexible Shaft ◽  
Er Fluid

This paper deals with a successful application of Electro-Rheological (ER) fluid to a squeeze film damper which enables a flexible rotor to reduce whirling amplitude by adjusting the damping property at each rotating speed. An experimental small scale model composed of a flexible shaft and a controllable ER squeeze film damper was constructed and its performance was studied under various electric field strengths. The ER fluid used in the present experiment was a colloidal suspension of silica powder in mineral oil. Furthermore, a theoretical approach to the performance of ER squeeze film damper was made in which the short bearing approximation of a journal bearing with Bingham plastic fluid was introduced. It is shown that the natural frequencies of a flexible shaft was increased continuously as the applied electric field was strengthened in the experiment, which was caused by the mode change due to supporting damping variation, and that the optimum damping for the flexible rotor in each rotating speed can always be applied by changing the applied voltage to the ER fluid squeeze film damper. It is also shown that the simplified theory introduced in this paper shows good agreement with the present experimental results.

Rotordynamic Evaluation of an Advanced Multi-Squeeze Film Damper: Imbalance Response and Bladeloss Simulation

1991 ◽  
Author(s):  
J. F. Walton ◽  
H. Heshmat
Keyword(s):  
Steady State ◽  
Rotor System ◽  
Squeeze Film ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Flexible Rotor ◽  
High Eccentricity ◽  
Squeeze Film Damper ◽  
Wide Range ◽  
Damper Design

In this paper results of rotordynamic response and transient tests of a novel, high load squeeze film damper design, are presented. The spiral foil multi-squeeze film damper has been previously shown to provide two to four fold or larger increases in damping levels without resorting to significantly decreased damper clearances or increased lengths. By operating with a total clearance of approximately twice conventional designs, the non-linearities associated with high eccentricity operation are avoided. Rotordynamic tests with a dual squeeze film configuration were completed. As a part of the overall testing program, a flexible rotor system was subjected to high steady state imbalance levels and transient simulated bladeloss events for up to 0.254 mm (0.01 in) mass c.g offset or 180 gm-cm (2.5 oz-in) imbalance. The spiral foil multi-squeeze film damper demonstrated that the steady state imbalance and simulated bladeloss transient response of a flexible rotor operating above its first bending critical speed could be readily controlled. Rotor system imbalance sensitivity and logarithmic decrement are presented showing the characteristics of the system with the damper installed. The ability to accommodate high steady state and transient imbalance conditions make this damper well suited to a wide range of rotating machinery, including aircraft gas turbine engines.

Rotordynamic Evaluation of an Advanced Multisqueeze Film Damper—Imbalance Response and Blade-Loss Simulation

1993 ◽  
Vol 115 (2) ◽  
pp. 347-352 ◽  
Author(s):  
J. F. Walton ◽  
H. Heshmat
Keyword(s):  
Steady State ◽  
Rotor System ◽  
Squeeze Film ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Flexible Rotor ◽  
Squeeze Film Damper ◽  
Wide Range ◽  
Damper Design ◽  
Blade Loss

In this paper results of rotordynamic response and transient tests of a novel, high load squeeze film damper design are presented. The spiral foil multisqueeze film damper has been previously shown to provide two to fourfold or larger increases in damping levels without resorting to significantly decreased damper clearances or increased lengths. By operating with a total clearance of approximately twice conventional designs, the nonlinearities associated with high-eccentricity operation are avoided. Rotordynamic tests with a dual squeeze film configuration were completed. As a part of the overall testing program, a flexible rotor system was subjected to high steady-state imbalance levels and transient simulated blade-loss events for up to 0.254 mm (0.01 in.) mass c. g. offset or 180 g-cm (2.5 oz-in.) imbalance. The spiral foil multisqueeze film damper demonstrated that the steady-state imbalance and simulated blade-loss transient response of a flexible rotor operating above its first bending critical speed could be readily controlled. Rotor system imbalance sensitivity and logarithmic decrement are presented showing the characteristics of the system with the damper installed. The ability to accommodate high steady-state and transient imbalance conditions make this damper well suited to a wide range of rotating machinery, including aircraft gas turbine engines.

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.

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.

Optimal Design of Squeeze Film Supports for Flexible Rotors

1983 ◽  
Vol 105 (3) ◽  
pp. 487-494 ◽  
Author(s):  
M. D. Rabinowitz ◽  
E. J. Hahn
Keyword(s):  
Optimal Design ◽  
Vibration Amplitude ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Rotor Vibration ◽  
Design Constraints ◽  
Supply Pressure ◽  
Flexible Rotors ◽  
Wide Range ◽  
Film Lubrication

Assuming central preloading, operation below the second bending critical speed, and full film lubrication, this paper presents a theoretical model which allows one, with minimum computation, to design squeeze film damped rotors under conditions of high unbalance loading. Closed form expressions are derived for the maximum vibration amplitudes pertaining to optimally damped conditions. The resulting vibration amplitude and transmissibility data of design interest are presented for a wide range of practical operating conditions on a single chart. It can be seen that for a given rotor, the lighter the bearing the more easily one can satisfy design constraints relating to allowable rotor vibration levels and lubricant supply pressure requirements. The data presented are shown to be applicable to a wide variety of rotors, and a recommended procedure for optimal design is outlined.

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