Study of Turbocharger Fully Floating Hydrodynamic Bearing Oil Whirl Behavior—Test and Prediction

Abstract This contribution investigates the influence of outgassing processes on the vibration behaviour of a hydrodynamic bearing supported turbocharger rotor. The examined rotor is supported radially by floating rings with outer squeeze-film damping and axially by thrust bearings. Due to the highly non-linear bearing properties, the rotor can be excited via the lubricating film, which results in sub-synchronous vibrations known as oil-whirl and oil-whip phenomena. A significant influence on the occurrence of oil-whip phenomena is attributed to the bearing stiffness and damping, which depend both on the kinematic state of the supporting elements and the thermal condition as well as the occurrence of outgassing processes. For modelling the bearing behaviour, the Reynolds equation with mass-conserving cavitation regarding the two-phase model and the 3D energy as well as heat conduction equation is solved. To evaluate the impact of cavitation, run-up simulations are carried out assuming a fully (Half-Sommerfeld) or partially filled lubrication gap. The resulting rotor responses are compared with the shaft motion measurement. Also, the normalized eccentricity, the minimum lubricant fraction and the thermal bearing condition are discussed.

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Stabilizing Hydrodynamic Bearing Oil Whip With μ-Synthesis Control of an Active Magnetic Bearing

Volume 7A: Structures and Dynamics ◽

10.1115/gt2015-44059 ◽

2015 ◽

Cited By ~ 3

Author(s):

Alexander H. Pesch ◽

Jerzy T. Sawicki

Keyword(s):

Rotation Speed ◽

Stability Limit ◽

Magnetic Bearing ◽

Active Magnetic Bearing ◽

Related Phenomenon ◽

Test Rig ◽

Hydrodynamic Bearing ◽

Oil Whip ◽

Oil Whirl ◽

Excited Vibration

Oil whip is a self-excited vibration in a hydrodynamic bearing which occurs when the rotation speed is above approximately twice the first natural frequency. Because of this, the oil whip phenomenon limits the operational speed of a rotor system on hydrodynamic bearings. Below the oil whip threshold, the related phenomenon of oil whirl can cause large vibrations at frequencies below half the rotation speed. A method is presented for stabilizing oil whip and oil whirl in a hydrodynamic bearing with an active magnetic bearing (AMB). The AMB controller is designed with μ-synthesis model-based robust control utilizing the Bently-Muszynska fluid film bearing model, which predicts the unstable phenomena. Therefore, the resulting AMB controller stabilizes the natural instability in the hydrodynamic bearing. Rotor speed is taken into account by use of a parametric uncertainty such that the method is robust to changes in running speed. The proposed method is demonstrated on an experimental hydrodynamic bearing test rig. Details of the test rig and implementation of the AMB controller design are presented. Waterfall plots for the controlled and uncontrolled system are presented which demonstrate the improved stability limit.

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Frequency Enhancement of Oil Whip and Oil Whirl in a Ferrofluid–Lubricated Hydrodynamic Bearing–Rotor System by Magnetic Field with Permanent Magnets

Applied Sciences ◽

10.3390/app8091687 ◽

2018 ◽

Vol 8 (9) ◽

pp. 1687

Author(s):

Liao-Yong Luo ◽

Yi-Hua Fan ◽

Jyh-Haw Tang ◽

Ting-Yu Chen ◽

Nai-Rong Zhong ◽

...

Keyword(s):

Magnetic Field ◽

Permanent Magnets ◽

Journal Bearing ◽

Rotor System ◽

Hydrodynamic Bearing ◽

System A ◽

Oil Whip ◽

Oil Whirl ◽

Hydrodynamic Journal Bearing ◽

Whirl Speed

The article describes the effect of a magnetic field applied to a ferrofluid–lubricated hydrodynamic journal bearing–rotor system. A rotor with a single journal bearing in one end was built to be the test rig. The experimental results showed that 3 to 8 permanent magnets, arranged by different methods, can all increase the instability threshold of the oil bearing. Especially, the magnetic field formed by eight magnets has the optimal effect. The whirl speed and the whip speed can be increased from 3024 rpm to 4480 rpm, and from 3184 rpm to 5268 rpm.

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Performance Study of Conical Hydrodynamic Bearing Under Different Semi Cone Angle on Conical Hydrodynamic Bearing Performance With Air Lubrication

SSRN Electronic Journal ◽

10.2139/ssrn.3363038 ◽

2018 ◽

Author(s):

Dinesh H. Kamble ◽

Vikas M. Phalle ◽

S.S. Mantha

Keyword(s):

Cone Angle ◽

Performance Study ◽

Hydrodynamic Bearing ◽

Air Lubrication

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A new concept of active hydrodynamic bearing for application in rotating systems

Tribology International ◽

10.1016/j.triboint.2020.106592 ◽

2021 ◽

Vol 153 ◽

pp. 106592

Author(s):

D.J. Ramos ◽

G.B. Daniel

Keyword(s):

Hydrodynamic Bearing ◽

Rotating Systems

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On the Vibration of a Translating String Coupled to Hydrodynamic Bearings

Journal of Vibration and Acoustics ◽

10.1115/1.2930513 ◽

1990 ◽

Vol 112 (3) ◽

pp. 337-345 ◽

Cited By ~ 6

Author(s):

C. A. Tan ◽

B. Yang ◽

C. D. Mote

Keyword(s):

Control System ◽

Transfer Function ◽

Spatial Location ◽

System Response ◽

Thickness Variation ◽

Translation Speed ◽

Impedance Function ◽

Hydrodynamic Bearing ◽

Loop Transfer Function ◽

Bearing Force

The vibration of a translating string, controlled through hydrodynamic bearing forces, is analyzed by the transfer function method. Interactions between the string response and the bearing film are described by the bearing impedance function. This function depends on the string translation speed, the frequency of the film thickness variation, and the spatial location of the bearings. The control system consists of the translating string, bearings, actuators and sensors, and feedback elements. An integral formulation of the controlled system response is proposed that leads to the closed-loop transfer function. The frequency response of the control system is studied in the system parameter space. The feasibility of adding active control to improve the bearing force control is also considered.

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Cyclic behavior test of a new double-arch steel gate

Journal of Zhejiang University SCIENCE A ◽

10.1631/jzus.2007.a1731 ◽

2007 ◽

Vol 8 (11) ◽

pp. 1731-1739

Author(s):

Yao-zhi Luo ◽

Shi-zhe Zhu ◽

Xi Chen

Keyword(s):

Cyclic Behavior ◽

Steel Gate ◽

Behavior Test

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Calculation and Measurement of the Stiffness and Damping Coefficients for a Low Impedance Hydrodynamic Bearing

Journal of Tribology ◽

10.1115/1.2832480 ◽

1997 ◽

Vol 119 (1) ◽

pp. 57-63 ◽

Cited By ~ 4

Author(s):

M. J. Goodwin ◽

P. J. Ogrodnik ◽

M. P. Roach ◽

Y. Fang

Keyword(s):

Experimental Data ◽

Dynamic Stiffness ◽

Perturbation Technique ◽

The Novel ◽

Oil Film ◽

Hydrodynamic Bearing ◽

Damping Coefficients ◽

Stiffness And Damping ◽

Film Stiffness ◽

Novel Design

This paper describes a combined theoretical and experimental investigation of the eight oil film stiffness and damping coefficients for a novel low impedance hydrodynamic bearing. The novel design incorporates a recess in the bearing surface which is connected to a standard commercial gas bag accumulator; this arrangement reduces the oil film dynamic stiffness and leads to improved machine response and stability. A finite difference method was used to solve Reynolds equation and yield the pressure distribution in the bearing oil film. Integration of the pressure profile then enabled the fluid film forces to be evaluated. A perturbation technique was used to determine the dynamic pressure components, and hence to determine the eight oil film stiffness and damping coefficients. Experimental data was obtained from a laboratory test rig in which a test bearing, floating on a rotating shaft, was excited by a multi-frequency force signal. Measurements of the resulting relative movement between bearing and journal enabled the oil film coefficients to be measured. The results of the work show good agreement between theoretical and experimental data, and indicate that the oil film impedance of the novel design is considerably lower than that of a conventional bearing.

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