scholarly journals Experimental Study on Vibration Reduction Characteristics of Gear Shafts Based on ISFD Installation Position

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Kaihua Lu ◽  
Lidong He ◽  
Yipeng Zhang
Keyword(s):  
Experimental Study ◽  
Vibration Reduction ◽  
First Grade ◽  
Spur Gear ◽  
Gear System ◽  
Experimental Results ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
System Vibration ◽  
Reduction Characteristics

A novel type of integral squeeze film damper (ISFD) is proposed to reduce and isolate vibration excitations of the gear system through bearing to the foundation. Four ISFD designs were tested experimentally with an open first-grade spur gear system. Vibration reduction characteristics were experimentally studied at different speeds for cases where ISFD elastic damping supports were simultaneously installed on the driving and driven shafts, installed on the driven shaft, or only installed on the driving shaft. Experimental results show that the ISFD elastic damping support can effectively reduce shock vibration of the gear system. Additionally, resonant modulation in gear shafts caused by meshing impact was significantly reduced. Different vibration amplitudes of gear shafts with ISFD installed only on driven or driving shafts were compared. Results indicated that vibration reduction is better when ISFD is only installed on the driven shaft than on the driving shaft.

Solution to a Bistable Vibration Problem Using a Plain, Uncentralized Squeeze Film Damper Bearing

1982 ◽  
Author(s):  
J. A. Palladino ◽  
T. W. Gray
Keyword(s):  
Exhaust System ◽  
Turbine Rotor ◽  
Field Investigation ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Engine Vibration ◽  
Cabin Noise ◽  
Rotor Support ◽  
System Vibration ◽  
Service Introduction

During service introduction of an uprated turbojet engine, which has a three-bearing rotor support system with an overhung turbine, several problems related to system vibration were encountered — cabin noise and high engine vibration levels. These problems led to a factory and field investigation which showed that the source of the problem was a nonlinear interaction between rotor and casing modes coupled through bearing clearance. This interaction led to a bistable vibration of the system. This paper documents the results of this investigation and demonstrates that the use of a plain, uncentralized, squeeze film damper to support the turbine rotor solves all vibration problems by reducing the turbine critical speed and separating it from the casing mode. Also included are effects of exhaust system weight on engine vibration and cabin noise levels.

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.

Dynamic Characterization of a Novel Externally Pressurized Compliantly Damped Gas-Lubricated Bearing With Hermetically Sealed Squeeze Film Damper Modules

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Adolfo Delgado ◽  
Bugra Ertas
Keyword(s):  
Degrees Of Freedom ◽  
Load Capacity ◽  
Operating Conditions ◽  
Experimental Results ◽  
Squeeze Film ◽  
Metal Mesh ◽  
Squeeze Film Damper ◽  
Drive Trains ◽  
Bearing Loads

Ever-increasing demand for cleaner energy is driving the need for higher power density turbomachinery while reducing cost and simplifying design. Gas-lubricated bearings are representing one of the enabling technologies that can help maximize these benefits and have been successfully implemented into turbomachinery applications with rotors weights in the order few kg's. However, load capacity and damping limitations of existing gas bearing technologies prevent the development of larger size oil-free drive trains in the MW power output range. Compliantly damped hybrid gas bearings (CHGBs) were introduced as an alternative design to overcome these limitations by providing external pressurization to discrete tilting pads while retaining flexibility in the bearing support to help tolerate misalignment and rotor-pad geometry changes. Additionally, the CHGB concept addresses damping entitlement through the application of bearing support dampers such as metal mesh. An alternative CHGB design, featuring a novel hermetically seal squeeze film damper (HSFD) in the bearing support, was introduced as alternative approach to metal mesh dampers (MMDs) to further improve bearing damping. This paper details the rotordynamic characterization of a CHGB with modular HSFD for various operating conditions. Direct and cross-coupled stiffness and damping coefficients are presented for different rotor speeds up to 12,500 rpm, frequencies of excitation between 20 and 200 Hz, bearing loads between 200 and 400 lbf, and external hydrostatic pressures reaching 180 psi. Direct comparisons to experimental results for a CHGB using MMD show 3× increase in direct damping levels when using HSFD in the compliant bearing support. In addition to the experimental results, an analytical model is presented based on the implementation of the isothermal compressible Reynolds equation coupled to a flexible support possessing a pad with three degrees-of-freedom. The numerical results capture the direct stiffness and frequency dependency but underpredict the absolute values for both cases when compared to experimental data.

Experimental Study of the Radial and Tangential Forces in a Whirling Squeeze Film Damper

2006 ◽  
Vol 49 (2) ◽  
pp. 271-278 ◽  
Author(s):  
Cyril Defaye ◽  
Mihaï Arghir ◽  
Olivier Bonneau ◽  
Philippe Carpentier ◽  
Charles Debailleux ◽  
...  
Keyword(s):  
Experimental Study ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Tangential Forces

Dynamic Characterization of a Novel Externally Pressurized Compliantly Damped Gas-Lubricated Bearing With Hermetically Sealed Squeeze Film Damper Modules

2018 ◽  
Author(s):  
Adolfo Delgado ◽  
Bugra Ertas
Keyword(s):  
Degrees Of Freedom ◽  
Load Capacity ◽  
Operating Conditions ◽  
Experimental Results ◽  
Squeeze Film ◽  
Metal Mesh ◽  
Squeeze Film Damper ◽  
Drive Trains ◽  
Bearing Loads

Ever-increasing demand for cleaner energy is driving the need for higher power density turbomachinery while reducing cost and simplifying design. Gas lubricated bearings, representing one of the enabling technologies that can help maximize these benefits and have been successfully implemented into turbomachinery applications with rotors weights in the order few kg’s. However, load capacity and damping limitations of existing gas bearing technologies prevents the development of larger size oil-free drive trains in the MW power output range. Compliantly damped hybrid gas bearings (CHGB) were introduced as an alternative design to overcome these limitations by providing external pressurization to discrete tilting pads while retaining flexibility in the bearing support to help tolerate misalignment and rotor-pad geometry changes. Additionally, the CHGB concept addresses damping entitlement through the application of bearing support dampers such a metal mesh. An alternative CHGB design, featuring a novel hermetically seal squeeze film damper (HSFD) in the bearing support, was introduced as alternative approach to metal mesh dampers (MMD) to further improve bearing damping. This paper details the rotordynamic characterization of a CHGB with modular HSFD for various operating conditions. Direct and cross-coupled stiffness and damping coefficients are presented for different rotor speeds up to 12,500 rpm, frequencies of excitation between 20–200 Hz, bearing loads between 200–400 1bf, and external hydrostatic pressures reaching 180psi. Direct comparisons to experimental results for a CHGB using (MMD) shows 3X increase in direct damping levels when using HSFD in the compliant bearing support. In addition to the experimental results, an analytical model is presented based on the implementation of the isothermal compressible Reynolds equation coupled to a flexible support possessing a pad with 3 degrees of freedom. The numerical results capture the direct stiffness and frequency dependency but underpredict the absolute values for both case when compared to experimental data.

scholarly journals Passive vibration reduction of a squeeze film damper for a rotor system with fit looseness between outer ring and housing

2020 ◽  
pp. 146134842096869
Author(s):  
Haifei Wang
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Reduction ◽  
Research Work ◽  
Contact Problems ◽  
Rotor System ◽  
Outer Ring ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Response Characteristics ◽  
Vibration Responses

Clearances between bearing outer ring and sleeve can generally be maintained to provide a margin for the thermal expansion of the bearings. However, temperature variation, improper assembly and long-term vibration can enlarge the clearances and accelerate mechanical wear, leading to what is known as the fit looseness fault. Therefore, it is important to study a fit looseness fault model and investigate how to control the vibration coming from the fit looseness fault. In this paper, a Jeffcott rotor system with three disks was modeled as a single unit. A fit looseness model was applied in the whole rotor model to study the contact problems and response characteristics using a numerical integration method. Then, a squeeze film damper model was applied to assess the vibration reduction effects on the whole rotor system with the fit looseness fault. By comparing the results of the fit looseness fault without squeeze film damper and with squeeze film damper, it is found that the squeeze film damper can reduce nonlinear vibration responses effectively generated by the fit looseness fault for the nonlinear contact. This research work contributes to understanding the mechanism of fit looseness fault and controlling strong nonlinear vibration responses due to the fit clearances.

Perturbation Solutions for Eccentric Operation of Squeeze Film Damper Systems

1986 ◽  
Vol 108 (4) ◽  
pp. 619-623 ◽  
Author(s):  
Xuehai Li ◽  
D. L. Taylor
Keyword(s):  
Numerical Simulation ◽  
Experimental Results ◽  
Squeeze Film ◽  
Rigid Rotor ◽  
Squeeze Film Damper ◽  
Synchronous Motion ◽  
Squeeze Film Dampers ◽  
Large Speed ◽  
Good Agreement ◽  
Perturbation Solutions

The study focuses on the effect of a small unidirectional load such as comes from imperfect balance between preloading on centering springs and gravitational load on squeeze film dampers. A rigid rotor-squeeze film damper system is considered, and a thorough study of the synchronous motion of the system is performed. Two perturbation solutions are developed: one for large speed and one for small speed. The perturbation solutions are shown to be in good agreement with numerical simulation and published experimental results.

scholarly journals Experimental study on transmission error of space-driven gear system under large inertia load

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985695 ◽  
Author(s):  
Jianfeng Ma ◽  
Chao Li ◽  
Jia Liu ◽  
Dongxing Cao ◽  
Jinfeng Huang
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Dominant Role ◽  
Transmission Error ◽  
Spur Gear ◽  
Gear System ◽  
Experimental Results ◽  
Normal Operation ◽  
Driving Mechanism ◽  
Set Up

There is a nonlinear disturbance problem in the operation of large inertia load space-driving mechanism, which seriously affects the normal operation of the system. A 14 degree-of-freedom nonlinear time-varying dynamic model was established for a two-stage spur gear system. The dynamic equations were solved numerically based on the Runge–Kutta method. The correctness of the dynamic model was verified through experiments. In the author’s previous research, the transmission error and dynamic response of gear system was analyzed. After the establishment of the dynamic model, a comparative analysis of the load response under different inertia was performed to illustrate the importance of studying large inertia loads. A large inertia load transmission error experimental device was set up to collect and process the transmission error data under different load inertia and different speeds. Comparing experimental results with numerical results, the correctness of the numerical model was verified, and the reasons for the differences between the two were explained. The analysis of the experimental results shows that for the transmission error of large inertia load gear transmission system, the influence of stiffness excitation on the transmission error amplitude is dominant. For the high-speed gear system, the pitch error plays a dominant role.

The Effect of Oil Supply and Sealing Arrangements on the Performance of Squeeze-Film Dampers: An Experimental Study

1996 ◽  
Vol 210 (4) ◽  
pp. 221-232 ◽  
Author(s):  
M C Levesley ◽  
R Holmes
Keyword(s):  
Experimental Study ◽  
Piston Ring ◽  
Squeeze Film ◽  
Damping Capacity ◽  
Squeeze Film Damper ◽  
Oil Supply ◽  
Squeeze Film Dampers

This paper compares the effects on the damping capacity of a squeeze-film damper of (a) changing the number of oil-feed holes to the central circumferential oil supply groove, (b) changing the sealing arrangement from end-seals to piston-ring seals, and (c) changing the position of the circumferential supply groove. The conclusions are that much improved damping performance is achieved by the piston-ring sealed arrangement. Unlike the end-sealed arrangement it is very little adversely influenced by a reduction in the number of oil-feed holes. The damping offered by either sealing arrangement is influenced only marginally by repositioning the supply groove.

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