Dynamic Analysis of a Coupled Dual-Rotor With Squeeze Film Damper Considering Sudden Unbalance

2021 ◽  
Author(s):  
Ying Cui ◽  
Yuxi Huang ◽  
Guogang Yang ◽  
Yongliang Wang ◽  
Han Zhang
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Rotor System ◽  
Lubricating Oil ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Oil Viscosity ◽  
Squeeze Film Damper ◽  
Damping Effect ◽  
Bistable State

Abstract A nonlinear multi-degree-of-freedom dynamic model of a coupled dual-rotor system with an intershaft bearing and uncentralized squeeze film damper is established by using finite element method. Based on the model, the critical speed characteristic diagram and vibration modes of the system were calculated. The steady-state unbalance response is obtained by using Newmark-β algorithm. The numerical results show the effect of SFD position in the dual-rotor system on response amplitude. It is found that with the decrease of radial clearance and the increase of length-diameter ratio and lubricating oil viscosity, the damping effect of SFD is enhanced and the bistable state phenomenon can be suppressed. The transient response of the system in case of sudden unbalance occurring at the fan was simulated by applying a step function. It is demonstrated that the SFD can effectively reduce the duration and maximum amplitude of the transient process, but at certain speeds, the SFD will increase the amplitude after the system returns to steady state, the damping effect on the transient response is also enhanced with the increase of length-diameter and the decrease of radial clearance, and with the increase of the sudden unbalance value, the response is more likely to stabilized at the high amplitude state of the bistable state.

Investigation of the Transient Response of a Dual-Rotor System With Intershaft Squeeze Film Damper

1985 ◽  
Author(s):  
Qihan Li ◽  
James F. Hamilton
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Transient Response ◽  
Synthesis Method ◽  
Gas Turbine Engine ◽  
Rotor System ◽  
Squeeze Film ◽  
High Pressure Turbine ◽  
Turbine Engine ◽  
Squeeze Film Damper

A method is presented for calculating the dynamics of a dual-rotor gas turbine engine equipped with a flexible intershaft squeeze-film damper. The method is based on the functional expansion component synthesis method. The transient response of the rotor due to a suddenly applied unbalance in the high-pressure turbine under different steady-speed operations is calculated. The damping effects of the intershaft damper and stability of the rotor system are investigated.

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.

Dynamical Behaviors of Hybrid Squeeze Film Damper for Rotor System Vibration Control

1995 ◽  
Author(s):  
Zhu Changsheng
Keyword(s):  
Rotor System ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Rigid Rotor ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Dynamical Behaviors ◽  
System Vibration ◽  
Stiffness And Damping ◽  
Film Stiffness

Abstract The behaviors of oil film stiffness and damping coefficients of the deep multi-recessed hybrid squeeze film damper (HSFD) with the orifices compensated are first analysed in this paper. The control ability of the HSFD on the rotor system vibrations is studied theoretically and experimentally with a rigid rotor system supported on the HSFD, and compared with that of the conventional squeeze film damper (SFD). Investigation shows that the HSFD not only can significantly improve the high nonlinearity of the SFD, but also can effectively control the rotor vibrational amplitudes, especially for larger rotor unbalance levels and radial clearance ratios, as compared with the SFD.

scholarly journals Investigation of the Steady-State Response of a Dual-Rotor System With Inter-Shaft Squeeze Film Damper

1985 ◽  
Author(s):  
Qihan Li ◽  
Litang Yan ◽  
James F. Hamilton
Keyword(s):  
Steady State ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Rotor System ◽  
Squeeze Film ◽  
Turbine Engine ◽  
Squeeze Film Damper ◽  
State Response ◽  
Unbalance Response

This paper presents an analysis of the steady-state unbalance response of a dual-rotor gas turbine engine with a flexible intershaft squeeze film damper using a simplified transfer matrix method. The simplified transfer matrix method is convenient for the evaluation of the critical speed and response of the rotor system with various supports, shaft coupling, intershaft bearing, etc. The steady-state unbalance response of the rotor system is calculated for different shaft rotation speeds. The damping effects of an intershaft squeeze film damper with different radial clearances under various levels of rotor unbalance are investigated.

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.

Investigation of the Transient Response of a Dual-Rotor System With Intershaft Squeeze-Film Damper

1986 ◽  
Vol 108 (4) ◽  
pp. 613-618 ◽  
Author(s):  
Qihan Li ◽  
J. F. Hamilton
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Transient Response ◽  
Synthesis Method ◽  
Gas Turbine Engine ◽  
Rotor System ◽  
Squeeze Film ◽  
High Pressure Turbine ◽  
Turbine Engine ◽  
Squeeze Film Damper

A method is presented for calculating the dynamics of a dual-rotor gas turbine engine equipped with a flexible intershaft squeeze-film damper. The method is based on the functional expansion component synthesis method. The transient response of the rotor due to a suddenly applied imbalance in the high-pressure turbine under different steady-speed operations is calculated. The damping effects of the intershaft damper and stability of the rotor system are investigated.

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.

Investigation of the Steady-State Response of a Dual-Rotor System With Intershaft Squeeze Film Damper

1986 ◽  
Vol 108 (4) ◽  
pp. 605-612 ◽  
Author(s):  
Qihan Li ◽  
Litang Yan ◽  
J. F. Hamilton
Keyword(s):  
Steady State ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Rotor System ◽  
Squeeze Film ◽  
Turbine Engine ◽  
Squeeze Film Damper ◽  
State Response ◽  
Unbalance Response

This paper presents an analysis of the steady-state unbalance response of a dual-rotor gas turbine engine with a flexible intershaft squeeze film damper using a simplified transfer matrix method. The simplified transfer matrix method is convenient for the evaluation of the critical speed and response of the rotor system with various supports, shaft coupling, intershaft bearing, etc. The steady-state unbalance response of the rotor system is calculated for different shaft rotation speeds. The damping effects of an intershaft squeeze film damper with different radial clearances under various levels of rotor unbalance are investigated.

Nonlinear Dynamic Study on Effects of Rub-Impact Caused by Oil-Rupture in a Multi-Shafts Turbine With a Squeeze Film Damper

2014 ◽  
Author(s):  
T. N. Shiau ◽  
C. R. Wang ◽  
D. S. Liu ◽  
W. C. Hsu ◽  
T. H. Young
Keyword(s):  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
Equations Of Motion ◽  
Rotor System ◽  
Squeeze Film ◽  
Speed Ratio ◽  
Frequency Spectra ◽  
Squeeze Film Damper ◽  
Assumed Mode Method ◽  
Nonlinear Dynamic Behavior

An investigation is carried out the analysis of nonlinear dynamic behavior on effects of rub-impact caused by oil-rupture in a multi-shafts turbine system with a squeeze film damper. Main components of a multi-shafts turbine system includes an outer shaft, an inner shaft, an impeller shaft, ball bearings and a squeeze film damper. In the squeeze film damper, oil forces can be derived from the short bearing approximation and cavitated film assumption. The system equations of motion are formulated by the global assumed mode method (GAMM) and Lagrange’s approach. The nonlinear behavior of a multi-shafts turbine system which includes the trajectories in time domain, frequency spectra, Poincaré maps, and bifurcation diagrams are investigated. Numerical results show that large vibration amplitude is observed in steady state at rotating speed ratio adjacent to the first natural frequency when there is no squeeze film damper. The nonlinear dynamic behavior of a multi-shafts turbine system goes in its way into aperiodic motion due to oil-rupture and it is unlike the usual way (1T = >2T = >4T = >8T etc) as compared to one shaft rotor system. The typical routes of bifurcation to aperiodic motion are observed in a multi-shafts turbine rotor system and they suddenly turn into aperiodic motion from the periodic motion without any transition. Consequently, the increasing of geometric or oil parameters such as clearance or lubricant viscosity will improve the performance of SFD bearing.

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