Dynamic Behavior of an Inherently Compensated Air Squeeze Film Damper

1975 ◽  
Vol 97 (4) ◽  
pp. 1399-1404 ◽  
Author(s):  
R. E. Cunningham
Keyword(s):  
Perturbation Theory ◽  
Dynamic Behavior ◽  
Squeeze Film ◽  
Pressure Perturbation ◽  
Squeeze Film Damper ◽  
Small Pressure ◽  
Excitation Frequencies ◽  
Experimental Values ◽  
Film Stiffness ◽  
Air Film

Experimental values of damping and stiffness were determined for an externally pressurized, inherently compensated, compressible squeeze-film damper up to excitation frequencies of 36,000 cycles/min. Experimental values of damping were higher than predicted by a small pressure perturbation theory at low squeeze numbers and less than predicted at high squeeze numbers. Experimental values of air film stiffness were less than the theory predicted at low squeeze numbers and much greater at higher squeeze numbers.

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

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.

Vibration analysis of a rotor supported on magnetorheological squeeze film damper with short bearing approximation: A contrast between short and long bearing approximations

2015 ◽  
Vol 23 (11) ◽  
pp. 1792-1808 ◽  
Author(s):  
Mostafa Irannejad ◽  
Abdolreza Ohadi
Keyword(s):  
Dynamic Behavior ◽  
Electrical Current ◽  
Magnetorheological Fluid ◽  
Squeeze Film ◽  
Fluid Viscosity ◽  
Squeeze Film Damper ◽  
Fluid Forces ◽  
Rotating Systems ◽  
Aspect Ratios ◽  
Variable Damping

Squeeze film dampers are widely used to reduce the vibration of rotating systems. Using magnetorheological fluid in these dampers can lead to a variable-damping damper called Magnetorheological Squeeze Film Damper (MRSFD). Magnetorheological fluid viscosity alter under different values of magnetic field. The previous research have widely used long bearing approximation to derive the equations governing the hydrodynamic behavior of MRSFDs. In this paper, the behavior of MRSFDs has been studied using short bearing approximation. Next, the effects of MRSFDs on the dynamic behavior of a flexible rotor have been studied, using finite element method (FEM). Synchronous whirl motion has not been imposed on the system behavior, as an external assumption. Damper pressure distribution and forces, dynamic trajectories, eccentricity and the frequency response of the rotor are tools used to analyze the dynamic behavior of MRSFDs and rotor system. As the results show, it seems to be more precise to use short bearing approximation to analyze dampers with aspect ratios lower than a limit (especially L/D < 1). Furthermore, by controlling electrical current one can control the dynamic behavior of a rotor, to avoid failure and damage. Finally, the whirl motion of the rotor was observed to remain synchronous, even when fluid forces are present.

Study of a Novel Squeeze Film Damper and Vibration Generator

1999 ◽  
Vol 122 (1) ◽  
pp. 211-218 ◽  
Author(s):  
C. V. Suciu ◽  
O. Bonneau ◽  
D. Brun-Picard ◽  
J. Fre^ne ◽  
M. D. Pascovici
Keyword(s):  
Reynolds Equation ◽  
Industrial Process ◽  
Vibration Damping ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Squeeze Film Effect ◽  
Stiffness And Damping ◽  
Film Stiffness ◽  
Wedge Effect ◽  
Theoretical Results

A novel squeeze film damper and vibration generator (SFD&VG) is proposed as an option in the vibration control field. The SFD&VG can be used as an active squeeze film damper (ASFD) or as a vibration generator (vibrator), for unidimensional vibration damping or generation. The SFD&VG concept is connected with current research to improve a common industrial process—drilling of deep holes. The SFD&VG is based on the variable area of the lubricant film, which allows the development of a variable force, and a change in fluid film stiffness and damping. The analysis is initiated for an elementary configuration of the SFD&VG—the infinite width Rayleigh step case—and then it is developed for an advanced elliptical SFD&VG. The Reynolds equation is solved for both pure squeeze film effect which provides vibration damping, and pure hydrodynamic wedge effect which provides vibration generation. The theoretical part is continued with the SFD&VG dynamic simulation. The SFD&VG experimental device and vibration measurements, performed for the two defined regimes, ASFD and vibration generator, are presented. Finally, the experimental and theoretical results are briefly compared. [S0742-4787(00)05201-2]

An Investigation of the Squeeze Film Between Rotating Annuli

1970 ◽  
Vol 92 (3) ◽  
pp. 435-440 ◽  
Author(s):  
C. W. Allen ◽  
A. A. McKillop
Keyword(s):  
Experimental Investigation ◽  
Melting Point ◽  
Liquid Metal ◽  
Decay Rates ◽  
Squeeze Film ◽  
Centrifugal Effect ◽  
Experimental Values ◽  
Free Falling ◽  
Air Film ◽  
Good Agreement

The squeeze film between two plane annuli is examined theoretically and experimentally. The theoretical analysis considers the inertia due to the “centrifugal effect” but neglects all other inertia terms. The experimental investigation is by means of a free-falling spinning rotor which is decelerated by the squeeze film. Fluids examined are kerosene, SAE 10 oil, and a low melting point liquid metal. Good agreement between the predicted and actual decay rates is obtained for kerosene but that for the oil and liquid metal is only fair. The theoretical and experimental values of film thickness are in good agreement. The results for the liquid metal suggest the possibility of a thin air film between the rotor and the liquid metal.

Development of an Efficient Oil Film Damper for Improving the Control of Rotor Vibration

1991 ◽  
Vol 113 (4) ◽  
pp. 557-562 ◽  
Author(s):  
Shiping Zhang ◽  
Litang Yan
Keyword(s):  
High Speed ◽  
Porous Metal ◽  
Porous Matrix ◽  
Squeeze Film ◽  
Oil Film ◽  
Squeeze Film Damper ◽  
Outer Race ◽  
Typical Experiment ◽  
Stiffness And Damping ◽  
Film Stiffness

An efficient oil film damper known as a porous squeeze film damper (PSFD) was developed for more effective and reliable vibration control of high-speed rotors based on the conventional squeeze film damper (SFD). The outer race of the PSFD is made of permeable sintered porous metal materials. The permeability allows some of the oil to permeate into and seep out of the porous matrix, with remarkable improvement of the squeeze film damping properties. The characteristics of PSFD oil film stiffness and damping coefficients and permeability, and also, the steady-state unbalance response of a simple rigid rotor and flexible Jeffcott’s rotor supported on PSFD and SFD are investigated. A typical experiment is presented. Investigations show that the nonlinear vibration characteristics of the unpressurized SFD system such as bistable jump phenomena and “lockup” at rotor pin-pin critical speeds could be avoided and virtually disappear under much greater unbalance levels with properly designed PSFD system. PSFD has the potential advantage of operating effectively under relatively large unbalance conditions.

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.

Vibration Characteristics of Squeeze Film Damper during Maneuver Flight

2015 ◽  
Vol 32 (2) ◽  
Author(s):  
Siji Wang ◽  
Mingfu Liao ◽  
Wei Li
Keyword(s):  
Centrifugal Force ◽  
Vibration Characteristics ◽  
Squeeze Film ◽  
Experimental Investigations ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Gyroscopic Moment ◽  
Aero Engine ◽  
Film Stiffness

AbstractThe rotor systems of an aero engine will endure additional centrifugal force and gyroscopic moment during maneuver flight. A maneuver fly mechanical simulator is designed and experimental investigations on dynamics of squeeze film damper (SFD) under the different additional centrifugal force and gyroscopic moment are carried out. The results show that the maneuver flight weaken effectiveness of the SFD, the additional centrifugal force and gyroscopic moment caused by maneuver flight will change film damping, film stiffness. And the influence of maneuver flight can be effective relieved by increasing the film clearance.

Nonlinear Dynamic Behavior of Turbocharger Rotor-Bearing Systems With Hydrodynamic Oil Film and Squeeze Film Damper in Series: Prediction and Experiment

2010 ◽  
Vol 5 (4) ◽  
Author(s):  
K. Gjika ◽  
L. San Andrés ◽  
G. D. Larue
Keyword(s):  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
High Performance ◽  
Squeeze Film ◽  
Inlet Temperature ◽  
Squeeze Film Damper ◽  
Feed Pressure ◽  
Nonlinear Dynamic Behavior ◽  
In Series ◽  
Bearing System

Current trends for advanced automotive engines focusing on downsizing, better fuel efficiency, and lower emissions have led to several changes in turbocharger bearing system design and technology. Automotive turbochargers run faster and use engine oils with very low viscosity under high oil inlet temperature and low feed pressure. The development of high performing bearing systems, marrying innovation with reliability, is a persistent challenge. This paper shows progress on the nonlinear dynamic behavior modeling of the rotor-radial bearing system (RBS) incorporating two oil films in series: a hydrodynamic one with a squeeze film damper commonly used in turbochargers. The developed fluid bearing code predicts bearing rotational speed (in the case of fully floating design), operating inner and outer bearing film clearances, effective oil viscosity, taking into account its shear effect, and hydrostatic load. A rotordynamics code uses this input to predict the nonlinear lateral dynamic response of the rotor-bearing system. The model predictions are validated with test data acquired on a high speed turbocharger RBS of a 6.0 mm journal diameter running up to 250,000 rpm (maximum speed), 5W30 oil type, 150°C oil inlet temperature, and 4 bar oil feed pressure. The tests are conducted at a rotordynamics technology laboratory using a high performance data acquisition system. Turbochargers with four combinations of inner and outer RBS clearances are tested. Prediction and measured synchronous response and total motion are in good agreement. Both demonstrate the nonlinear character of the RBS behavior, including several subsynchronous frequency components across the operating speed range. The nonlinear predictive model aids the development of high performance and optimized turbocharger RBS with faster development cycle times and increased reliability.

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