Experimental Vibration and Lubricant Analysis of Oil whirl in Kind of Self-Excited Vibration Generated in Sliding Bearing

Floating-ring bearings are commonly used in automotive turbocharger applications due to their low cost and their suitability under extreme rotation speeds. This type of bearings, however, can become a source of noise due to oil whirl-induced sub-synchronous vibrations. The scope of this paper is to examine whether the concept of a floating-ring bearing with an elliptical clearance might be a solution to suppress sub-synchronous vibrations. A very time-efficient approximate solution for the Reynolds equation to the geometry of elliptical bearings is presented. The nonlinear dynamic behaviors of a turbocharger rotor supported by two concepts of elliptical floating-ring bearings are systematically investigated using run-up simulations. For the first concept of elliptical floating-ring bearings i.e. the outer bearing of the floating-ring bearing changed in the form of elliptical pattern (see Figure 1(b) in the article), some studies have pointed out that its steady-state and dynamic performances are superior to plain cylindrical floating-ring bearings but, the nonlinear run-up simulation results shown that this type of elliptical floating-ring bearings is not conducive to reduce the self-excited vibration levels. However, for the second type of elliptical floating-ring bearings i.e. both the inner and outer films of the floating-ring bearing changed in the form of elliptical pattern (see Figure 1(c) in the article), it is shown that the sub-synchronous vibrations have been considerably suppressed. Hence, the second noncircular floating-ring bearing design is an attractive measure to suppress self-excited vibrations.[Figure: see text]

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Stepwise Intelligent Diagnosis Method for Rotor System with Sliding Bearing Based on Statistical Filter and Stacked Auto-Encoder

Applied Sciences ◽

10.3390/app10072477 ◽

2020 ◽

Vol 10 (7) ◽

pp. 2477

Author(s):

Haihong Tang ◽

Zhiqiang Liao ◽

Yayoi Ozaki ◽

Peng Chen

Keyword(s):

Signal To Noise Ratio ◽

Binary Classification ◽

Health Condition ◽

Rotor System ◽

Sliding Bearing ◽

Intelligent Diagnosis ◽

Fault Features ◽

Oil Whirl ◽

Diagnosis Method ◽

The Relationship

Since the raw signal collected from the sliding bearing is contaminated with background noise, and it is difficult to obtain high-precision results for the traditional methods due to the low signal-to-noise ratio (SNR). Therefore, a stepwise intelligent diagnosis method based on statistical filter and stacked auto-encoder (SAE) that is established with several auto-encoders is proposed to identify several faults of sliding bearing in a rotor system. Firstly, the statistical filter is utilized to reduce the interference information for the different abnormal states and to increase the SNR. Secondly, the stepwise intelligent diagnosis based on SAE is performed to learn the useful fault features, and it can automatically complete the fault diagnosis which is contributed with the superiority binary classification to fully mine the relationship between the fault characteristics and the health condition of bearing. Finally, the diagnosis of the oil whirl and structural faults in a rotor system is cited as an example to demonstrate the effectiveness of proposed method. It can effectively illustrate the advantages of the stepwise diagnosis method to obtain the maximum diagnostic accuracy.

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Active Self-Excited Vibration Elimination of Rotating Machine With an Electromagnetic Exciter

Volume 1: 22nd Biennial Conference on Mechanical Vibration and Noise, Parts A and B ◽

10.1115/detc2009-86405 ◽

2009 ◽

Cited By ~ 1

Author(s):

Chen-Chao Fan ◽

Min-Chun Pan

Keyword(s):

Journal Bearings ◽

Rotor System ◽

Stable Method ◽

Rotating Machine ◽

Oil Whip ◽

Control Scheme ◽

Oil Whirl ◽

Excited Vibration ◽

Load Carrying ◽

Auxiliary Device

Journal bearings are commonly used in large rotary machineries because they have excellent mechanical and geometric properties as well as large load-carrying capacities. Nevertheless, the oil whirl and oil whip instabilities limit their applications due to their insufficient stiffness at high running speeds. This paper presents a method to increase the stiffness of a rotating machine using an electromagnetic exciter (EE), which can raise the threshold of instability of the rotating machine and eliminate fluid-induced instability. The EE is a controllable auxiliary device that can provide additional stiffness to the bearings to increase the operating ranges of a rotating machine, while the journal bearings act as load-carrying devices. Together, the EE complements the JB to stiffen the rotor system and raise the threshold of instability. A simple control scheme is used to calculate the amount of supplemental stiffness supplied by the EE. The experimental results demonstrate that the oil whirl and oil whip instabilities of the rotating machine can be eliminated effectively, even at higher running speeds. The advantage of the EE is to offer a faster, more stable method to eliminate fluid-induced instability.

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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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The Fault Analysis and Research of Turbine Generator Sliding Bearing Oil Film Instability

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.915-916.198 ◽

2014 ◽

Vol 915-916 ◽

pp. 198-202

Author(s):

Guo Dong Han ◽

Zhang Qin Wu ◽

Shu Ting Wan ◽

Zhan Jie Lv ◽

Rong Hai Liu ◽

...

Keyword(s):

Spectral Characteristics ◽

Fault Analysis ◽

Turbine Generator ◽

Sliding Bearing ◽

Oil Film ◽

Oil Whip ◽

Film Instability ◽

Oil Whirl ◽

Whirl Speed ◽

The Time Domain

This article are discussed Sliding Bearing for Turbine instability failure research status in detail; Gives the theoretical analysis On sliding bearing oil film instability failure mechanism, to further explore the oil whirl and oil whip manifestations and signal spectral characteristics. And analysis of the oil whirl speed changes the vibration characteristics of typical regions, given the time-domain waveform oil whirl and oil whip axis trajectory. Details of the turbine generator film and the main reason for the instability factors and made a film instability fault governance approach. It helped for Fault Diagnosis of Turbine film and achieving security and stability of Turbine provides technical reference.

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Emergence of tangential stiffness through the use of inclined orthotropic material

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220967965 ◽

2020 ◽

pp. 095440622096796

Author(s):

Tadayoshi Shoyama ◽

Yutaka Wada ◽

Osami Matsushita

Keyword(s):

Orthotropic Material ◽

Tangential Force ◽

Reaction Force ◽

Tangential Stiffness ◽

Oil Whirl ◽

Excited Vibration ◽

Rotationally Symmetric ◽

Tangential Forces ◽

Degree Of Anisotropy ◽

Stabilization Effect

A flexible bearing support structure is effective for stabilizing the self-excited vibration of a bearing, such as oil whirl. The stabilization effect is increased if the structure has static tangential stiffness, where the reaction force is perpendicular to the displacement. In this study, it is shown that a support component made of inclined orthotropic material, which exhibits shear–extension coupling, can have tangential stiffness.　The circumferential average of the tangential stiffness was found to vanish with a rotationally symmetric configuration of these components because the tangential forces of each component cancel out. However, the tangential force was recovered by allowing separation on the contact surface. A circular formation of an inclined orthotropic sheet that shows an axisymmetric stiffness matrix is proposed. Theoretical and numerical analyses clarified the effects of the friction coefficient, fitting interference, and degree of anisotropy of the material. Zero interference was found to be the best condition to maximize tangential stiffness.

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