Static and Dynamic Characteristics of Externally Pressurized Porous Gas Journal Bearing With Four Degrees-of-Freedom

This paper studies the static and dynamic coefficients of an externally pressurized porous gas journal bearing. The finite difference method is used to solve the Reynolds equation of the bearing to obtain the static load capacity. The linear perturbation method is adopted to derive the perturbation equations considering four degrees-of-freedom (4DOF), namely, the translational movements in x and y directions and the rotational movements around x and y directions. The effects of various parameters on the dynamic behaviors of the journal bearing are studied. These parameters include the bearing number, the supply pressure, the feeding parameter, the length-to-diameter ratio, the porosity parameter, the eccentricity ratio, and tilting angles. Simulated results prove that the proposed method is valid in estimating the static and dynamic characteristics of a porous gas journal bearing with 4DOF.

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Static and Dynamic Characteristics of Self-Acting, Partial-Arc, Gas Journal Bearings

Journal of Basic Engineering ◽

10.1115/1.3653089 ◽

1964 ◽

Vol 86 (2) ◽

pp. 405-413 ◽

Cited By ~ 1

Author(s):

R. J. Wernick ◽

C. H. T. Pan

Keyword(s):

Power Series ◽

Dynamic Characteristics ◽

Reynolds Equation ◽

Journal Bearing ◽

Standard Form ◽

Journal Bearings ◽

Static And Dynamic Characteristics ◽

Stability Derivatives ◽

Bearing Loads ◽

Gas Journal Bearing

The Reynolds equation applicable to a self-acting partial-arc gas journal bearing is perturbed in terms of the compressibility number Λ. The resulting set of equations is then put into a standard form and Galerkin’s method is used to obtain bearing loads and stability derivatives. These results are expressed in a power series in Λ.

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Performance of textured foil journal bearing considering the influence of relative texture depth

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/13506501211072991 ◽

2022 ◽

pp. 135065012110729

Author(s):

Guanghui Zhang ◽

Kefan Xu ◽

Jiazhen Han ◽

Yanzhong Huang ◽

Wenjie Gong ◽

...

Keyword(s):

Iterative Method ◽

Dynamic Characteristics ◽

Reynolds Equation ◽

Journal Bearing ◽

Load Capacity ◽

Surface Texturing ◽

Static And Dynamic Characteristics ◽

Foil Bearing ◽

Newton Raphson ◽

Maximum Increment

Both foil structure and surface texturing have been widely used to improve bearing performance. However, there is little research on their combination, namely, textured gas foil bearing. This paper adopts the Reynolds equation as the pressure governing equation of bump-type foil journal bearing to study the influence of textures located on the top foil. The Newton-Raphson iterative method and the perturbation method are employed to obtain static and dynamic characteristics, respectively. Thereafter, based on three texture distribution types, further analysis about the effect of the relative texture depth and the textured portion is carried out. The results indicate that an appropriate arrangement of textures could improve the performance of gas foil bearing. For #1 texture distribution, the maximum increment of load capacity could exceed 10% when ω = 1.4 × 105 r/min, ε = 0.2.

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Misalignment Effect on the Static and Dynamic Characteristics of Hydrodynamic Journal Bearings

Journal of Tribology ◽

10.1115/1.2831542 ◽

1995 ◽

Vol 117 (4) ◽

pp. 717-723 ◽

Cited By ~ 15

Author(s):

Z. L Qiu ◽

A. K. Tieu

Keyword(s):

Dynamic Characteristics ◽

Reynolds Equation ◽

Static Load ◽

Load Capacity ◽

Vertical Direction ◽

Journal Bearings ◽

Static And Dynamic Characteristics ◽

Flow Friction ◽

The Stability ◽

Side Flow

This paper solves the Reynolds equation by the finite difference method in a fixed coordinate system with the static load acted in the vertical direction. All static and dynamic characteristics (including load capacity, attitude angle, side flow, friction force, misaligned moments, and eight linear force coefficients) of a horizontally grooved bearing under different eccentricity and misalignment conditions are presented and compared with available experimental data. The effects of misalignment on all these bearing characteristics and on the stability of the rotor-bearing system are analyzed.

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Effect of angular misalignment on the dynamic characteristics of externally pressurized air journal bearing

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650119858243 ◽

2019 ◽

Vol 234 (2) ◽

pp. 205-228

Author(s):

Jianghai Shi ◽

Hongrui Cao ◽

Xuefeng Chen

Keyword(s):

Dynamic Characteristics ◽

Degrees Of Freedom ◽

Reynolds Equation ◽

Journal Bearing ◽

Dynamic Stiffness ◽

State Equation ◽

Linear Perturbation ◽

Angular Misalignment ◽

Dynamic Performances ◽

Perturbation Frequency

This paper studies the effect of angular misalignment on the dynamic characteristics of externally pressurized air journal bearing with four degrees of freedom. The linear perturbation method is applied to the Reynolds equation to obtain the steady-state equation and perturbation equations, and then the finite difference method and an iterative method are used to solve the Reynolds equation. Various eccentricity ratios and rotating speeds are taken into considerations for the comparisons of dynamic stiffness coefficients and damping coefficients of the air journal bearing under different tilt angles. In addition, the influences of perturbation frequency ratio on the dynamic performances of the air journal bearing are also estimated.

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Analysis of static and dynamic characteristics of spiral-grooved gas journal bearings in high speed

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

10.1177/0954406219869751 ◽

2019 ◽

Vol 233 (19-20) ◽

pp. 6774-6792 ◽

Cited By ~ 1

Author(s):

Laiyun Song ◽

Kai Cheng ◽

Hui Ding ◽

Shijin Chen ◽

Qiang Gao

Keyword(s):

Dynamic Characteristics ◽

High Speed ◽

Load Capacity ◽

Structural Parameters ◽

Dynamic Stiffness ◽

Journal Bearings ◽

Linear Perturbation ◽

Static And Dynamic Characteristics ◽

Gas Bearings ◽

Spiral Grooves

The spiral grooves structures could promote load capacity and improve stability of the gas journal bearings working in high-speed condition. In this study, the unsteady Reynolds equation is solved by linear perturbation method and finite difference method in which the mesh of the groove region is specially treated. The static and dynamic characteristics of spiral grooves journal gas bearings are investigated in different working conditions and the pumping effect caused by spiral-groove structure is revealed and analyzed. Further, the influences of groove structural parameters on the dynamic stiffness and damping coefficients are studied and discussed, which provides guidelines for the design of the journal gas bearings with spiral grooves.

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Numerical analysis on the performance characteristics of a new gas journal bearing by using finite difference method

Advances in Mechanical Engineering ◽

10.1177/16878140211028056 ◽

2021 ◽

Vol 13 (6) ◽

pp. 168781402110280

Author(s):

Yuntang Li ◽

Ruirui Li ◽

Yueliang Ye ◽

Xiaolu Li ◽

Yuan Chen

Keyword(s):

Finite Difference ◽

Finite Difference Method ◽

Difference Method ◽

Journal Bearing ◽

Load Capacity ◽

Linear Perturbation ◽

Eccentricity Ratio ◽

Dynamic Performances ◽

The Stability ◽

Gas Journal Bearing

This paper proposes a novel gas journal bearing in which orifices are different in diameter and distribute unevenly. Finite Difference Method (FDM) combined with Linear Perturbation Method (LPM) is used to solve the unsteady-state Reynolds equation of the flow field in the bearing clearance. Moreover, four types of bearing structures are used to discuss the effects of orifices different in diameter and uneven distribution on the bearing performance. The results demonstrate that the new bearing has better static and dynamic performances compared with those of traditional bearing in which orifices are equal in diameter and distribute evenly. Moreover, thin gas film thickness, high supply pressure, and large eccentricity ratio are hopeful for improving load capacity of the new bearing. Furthermore, the stability of the novel bearing is improved if eccentricity ratio is 0.25–0.3.

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Extension of the Patir-Cheng Flow Simulation of a Rough Surface Bearing to a Compressible Lubricant

Journal of Mechanical Engineering Science ◽

10.1243/jmes_jour_1982_024_039_02 ◽

1982 ◽

Vol 24 (4) ◽

pp. 209-214

Author(s):

B. C. Majumdar ◽

B. J. Hamrock

Keyword(s):

Reynolds Equation ◽

Journal Bearing ◽

Load Capacity ◽

Roughness Parameter ◽

Flow Simulation ◽

Surface Structures ◽

Surface Pattern ◽

Hydrodynamic Load ◽

Gas Journal Bearing ◽

Compressible Lubricant

It is shown that the average Reynolds equation for rough surfaces using an incompressible lubricant derived by Patir and Cheng (1)§ can be used for a compressible lubricant if the surface structures of both surfaces are the same. The average Reynolds equation is applied to an infinitely long gas journal bearing to find the hydrodynamic load capacity. The effect of the roughness parameter and the surface pattern parameter on the hydrodynamic load is also investigated.

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A General Solution of Reynolds’ Equation for a Full Finite Journal Bearing

Journal of Lubrication Technology ◽

10.1115/1.3616949 ◽

1967 ◽

Vol 89 (2) ◽

pp. 203-210 ◽

Cited By ~ 2

Author(s):

R. R. Donaldson

Keyword(s):

Fourier Series ◽

Series Solution ◽

Reynolds Equation ◽

Journal Bearing ◽

Load Capacity ◽

Separation Of Variables ◽

Hill Equation ◽

Eigenvalues And Eigenvectors ◽

General Series ◽

Bearing Load

Reynolds’ equation for a full finite journal bearing lubricated by an incompressible fluid is solved by separation of variables to yield a general series solution. A resulting Hill equation is solved by Fourier series methods, and accurate eigenvalues and eigenvectors are calculated with a digital computer. The finite Sommerfeld problem is solved as an example, and precise values for the bearing load capacity are presented. Comparisons are made with the methods and numerical results of other authors.

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