Stability analysis of Morton effect for journal bearing based on control engineering

Abstract In recent years, rotating machinery has been required to operate at high rotational speeds for high efficiency. However, with increase in the rotational speed, the rotating machinery may become unstable. One cause of unstable vibrations is the Morton effect that occurs in journal bearings. Thus, developing a mathematical model to predict the Morton effect is desirable to avoid the occurrence of such unstable vibrations. In this study, a model based on a frequency response that can quantitatively evaluate the Morton-effect-induced vibrations in rotating machinery supported by a journal bearing was developed. Experimental data were collected for modeling by using an experimental rig. Using the experimental data pertaining to the journal position in the journal bearing and temperature of the journal, a model for the Morton effect was established based on the frequency responses. From a control engineering viewpoint, the journal bearing was considered to be a proportional differential controller. In addition, the Morton-effect-induced vibrations were considered as a new bending mode of a rotating shaft, caused by thermal differences. Subsequently, the developed model was evaluated in the frequency domain. The characteristics of the vibrations, determined using the proposed model, exhibited good correlation with those corresponding to experimental data. The experimental data agreed well with the predicted results, and the results demonstrated the usefulness of the proposed method for predicting the Morton effect.

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Analysis of Morton Effect Induced Vibration based on Transfer Function Model: Influence of L/D ratio of Journal Bearing and Rotational speed

Journal of Physics Conference Series ◽

10.1088/1742-6596/1909/1/012079 ◽

2021 ◽

Vol 1909 (1) ◽

pp. 012079

Author(s):

Takafumi Suzuki ◽

Jotaro Chiba ◽

Shota Yabui ◽

Shigeyuki Tomimatsu ◽

Tsuyoshi Inoue

Keyword(s):

Transfer Function ◽

Rotational Speed ◽

Journal Bearing ◽

Transfer Function Model ◽

Function Model ◽

Morton Effect

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Non-linear stability analysis of micropolar fluid lubricated journal bearings with turbulent effect

Industrial Lubrication and Tribology ◽

10.1108/ilt-07-2017-0212 ◽

2019 ◽

Vol 71 (1) ◽

pp. 31-39

Author(s):

Subrata Das ◽

Sisir Kumar Guha

Keyword(s):

Stability Analysis ◽

Linear Stability ◽

Micropolar Fluid ◽

Journal Bearing ◽

Journal Bearings ◽

Turbulent Regime ◽

Content Type ◽

Non Linear ◽

The Stability ◽

Bearing System

Purpose The purpose of this paper is to investigate the effect of turbulence on the stability characteristics of finite hydrodynamic journal bearing lubricated with micropolar fluid. Design/methodology/approach The non-dimensional transient Reynolds equation has been solved to obtain the non-dimensional pressure field which in turn used to obtain the load carrying capacity of the bearing. The second-order equations of motion applicable for journal bearing system have been solved using fourth-order Runge–Kutta method to obtain the stability characteristics. Findings It has been observed that turbulence has adverse effect on stability and the whirl ratio at laminar flow condition has the lowest value. Practical implications The paper provides the stability characteristics of the finite journal bearing lubricated with micropolar fluid operating in turbulent regime which is very common in practical applications. Originality/value Non-linear stability analysis of micropolar fluid lubricated journal bearing operating in turbulent regime has not been reported in literatures so far. This paper is an effort to address the problem of non-linear stability of journal bearings under micropolar lubrication with turbulent effect. The results obtained provide useful information for designing the journal bearing system for high speed applications.

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Stability Analysis of Partial Slip Texture Journal Bearing

Lecture Notes in Mechanical Engineering - Proceedings of the 6th National Symposium on Rotor Dynamics ◽

10.1007/978-981-15-5701-9_18 ◽

2020 ◽

pp. 217-225

Author(s):

T. V. V. L. N. Rao ◽

Ahmad Majdi Abdul Rani ◽

Norani Muti Mohamed ◽

Hamdan Haji Ya ◽

Mokhtar Awang ◽

...

Keyword(s):

Stability Analysis ◽

Journal Bearing ◽

Partial Slip

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Linear stability analysis of finite hydrodynamic journal bearing under turbulent lubrication with coupled-stress fluid

Industrial Lubrication and Tribology ◽

10.1108/ilt-07-2015-0094 ◽

2016 ◽

Vol 68 (3) ◽

pp. 386-391 ◽

Cited By ~ 4

Author(s):

Abhishek Ghosh ◽

Sisir Kumar Guha

Keyword(s):

Stability Analysis ◽

Newtonian Fluid ◽

High Speed ◽

Journal Bearing ◽

Slenderness Ratio ◽

Linear Perturbation ◽

Content Type ◽

Hydrodynamic Journal Bearing ◽

The Stability ◽

Coupled Stress

Purpose Several researchers have observed that to satisfy modern day’s need, it is essential to enhance the characteristics of journal bearing, which is used in numerous applications. Moreover, the use of Newtonian fluid as a lubricant is diminishing day by day, and the use of Non-Newtonian fluids is coming more into picture. Furthermore, if turbo-machinery applications are taken into account, then it can be seen that journal bearings are used for high speed applications as well. Thus, neglecting turbulent conditions may lead to erroneous results. Hence, this paper aims to present focuses on studying the stability characteristics of finite hydrodynamic journal bearing under turbulent coupled-stress lubrication. Design/methodology/approach First, the governing equation relevant to the problem is generated. Then, the dynamic analysis is carried out by linear perturbation technique, leading to three perturbed equations, which are again discretized by finite difference method. Finally, these discretized equations are solved with the help of Gauss-Seidel Iteration technique with successive over relaxation scheme. Consequently, the film response coefficients and the stability parameters are evaluated at different parametric conditions. Findings It has been concluded from the study that with increase in value of the coupled-stress parameter, the stability of the journal may increase. Whereas, with increase in Reynolds number, the stability of the journal decreases. On the other hand, stability increases with increasing values of slenderness ratio. Originality/value Researches have been performed to study the dynamic characteristics of journal bearing with non-Newtonian fluid as the lubricant. But in the class of non-Newtonian lubricants, the use of coupled-stress fluid has not yet been properly investigated. So, an attempt has been made to perform the stability analysis of bearings with coupled-stress fluid as the advanced lubricant.

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Stability Analysis of an Unbalanced Journal Bearing with Nonlinear Hydrodynamic Forces

Proceedings of the 9th IFToMM International Conference on Rotor Dynamics - Mechanisms and Machine Science ◽

10.1007/978-3-319-06590-8_88 ◽

2015 ◽

pp. 1081-1090 ◽

Cited By ~ 1

Author(s):

Radhouane Sghir ◽

Mnaouar Chouchane

Keyword(s):

Stability Analysis ◽

Journal Bearing ◽

Hydrodynamic Forces

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Nonlinear Simulation Analysis and Experiment of Fluid Plain Journal Bearing With Incompressible Fluid

Volume 5: 19th Biennial Conference on Mechanical Vibration and Noise, Parts A, B, and C ◽

10.1115/detc2003/vib-48415 ◽

2003 ◽

Author(s):

Katsuhisa Fujita ◽

Atsuhiko Shintani ◽

Koji Yoshioka ◽

Kouhei Okuno ◽

Hiroaki Tanaka ◽

...

Keyword(s):

Stability Analysis ◽

Incompressible Fluid ◽

Journal Bearing ◽

Simulation Analysis ◽

Journal Bearings ◽

Stable Region ◽

Flexible Rotor ◽

Nonlinear Simulation ◽

Fluid Forces ◽

The Stability

Recently, in many areas such as computers and information equipments etc., the fluid journal bearings are required to rotate at higher speed. To satisfy this requirement, the strictly stability analysis of the journal is indispensable. In this paper, we investigate the stability analysis of the dynamic behavior of the fluid plain journal bearing with an incompressible fluid considering the nonlinear terms of fluid forces. The stability analysis is examined by the numerical simulations on each model of a rigid rotor and a flexible rotor. The stable regions by nonlinear analysis are compared with the regions by classical linear analysis. Performing the nonlinear simulation analysis, it becomes clear that there is rather a stable region which amplitude does not grow up abruptly, and this phenomenon can not only be pointed out, but also is judged to be unstable by linear stable analysis. Finally, the experiment using actual bearings is performed and compared with the numerical results.

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