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.

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.

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.

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.

Experimental research on suppressing unbalanced vibration of rotor by integral squeeze film damper

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wei Yan ◽  
Lidong He ◽  
Zhe Deng ◽  
Xingyun Jia
Keyword(s):  
Rotational Speed ◽  
Critical Speed ◽  
Structural Characteristics ◽  
Experimental Studies ◽  
Rotor System ◽  
Squeeze Film ◽  
Rigid Rotor ◽  
Flexible Rotor ◽  
Test Rig ◽  
Squeeze Film Damper

Abstract As a novel structural damper, the unique structural characteristics of the integral squeeze film damper (ISFD) solve the nonlinear problem of the traditional squeeze film damper (SFD), and it has good linear damping characteristics. In this research, the experimental studies of ISFD vibration reduction performance are carried out for various working conditions of unbalanced rotors. Two ball bearing-rotor system test rigs are built based on ISFD: a rigid rotor test rig and a flexible rotor test rig. When the rotational speed of rigid rotor is 1500 rpm, ISFD can reduce the amplitude of the rotor by 41.79%. Under different unbalance conditions, ISFD can effectively improve the different degrees of unbalanced faults in the rotor system, reduce the amplitude by 43.21%, and reduce the sensitivity of the rotor to unbalance. Under different rotational speed conditions, ISFD can effectively suppress the unbalanced vibration of rigid rotor, and the amplitude can be reduced by 53.51%. In the experiment of the unbalanced response of the flexible rotor, it is found that ISFD can improve the damping of the rotor system, effectively suppress the resonance of the rotor at the critical speed, and the amplitude at the first-order critical speed can be reduced by 31.72%.

Sliding Mode Control of Flexible Rotor Based on Estimated Model of Magnetorheological Squeeze Film Damper

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Masoud Hemmatian ◽  
Abdolreza Ohadi
Keyword(s):  
Pid Controller ◽  
Sliding Mode ◽  
Rotor System ◽  
Lubricating Oil ◽  
Squeeze Film ◽  
Stiffness Coefficient ◽  
Flexible Rotor ◽  
Mr Fluid ◽  
Squeeze Film Damper ◽  
Sliding Mode Controllers

By using magnetorheological (MR) fluid as the lubricating oil in a traditional squeeze film damper (SFD), one can build a variable-damping SFD, thereby controlling the vibration of a rotor by controlling the magnetic field. This study aims to control the vibration of a flexible rotor system using a magnetorheological squeeze film damper (MR-SFD). In order to evaluate the performance of the damper, the Bingham plastic model is used for the MR fluid and the hydrodynamic equation of MR-SFD is presented. Usually, the numerical methods are necessary for solving this equation. These methods are too costly and time consuming, especially in the simulation of complex rotors and the implementation of model-based controllers. To fix this issue, an innovative estimated equation for pressure distribution in MR-SFD is presented in this paper. By integration of this explicit expression, the hydrodynamic forces of MR-SFD are easily calculated as an algebraic equation. It is shown that the pressure and forces, which are calculated from the introduced expression, are consistent with the corresponding results of the original equations. Furthermore, considering the structural and parametric uncertainties of the system, proportional-integral-furthermore controller (PID) and sliding mode controllers are chosen for reducing the vibration level of the flexible rotor system, which is modeled by the finite element method. The time and frequency responses of a flexible rotor in the presence of these controllers show a good performance in reducing vibration of the shaft's midpoint, although near the rotor's critical speed the results of the sliding mode controller (SMC) are better than the corresponding results of the PID controller. The last part of this article is devoted to an analysis of the system's uncertainties. The results of the open loop system indicate that changes in the stiffness coefficient of the elastic foundation and the temperature of the MR fluid (two uncertainties of the system) strongly affects the outputs while using the controllers well increases the robustness of the system. The obtained results indicate that both the PID and sliding mode controllers have good performance against the uncertainty of the stiffness coefficient, but for changes in the MR fluid's temperature, the SMC presents better outputs compared to the PID controller, especially for high rotational speeds.

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.

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.

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