An optimal method of distribution of the slip zone on thrust bearing surfaces

Research to achieve a reasonable distribution of the slip zone of the sliding pair for better improvement of the hydrodynamic pressure of the liquid film is an intractable topic. To solve this issue, this paper takes the thrust bearing as the research object, and proposes to use the position number of the grid nodes at the boundary line between the slip and no-slip zone in each radial zone of the inclined pad to be variables. The variables are then defined as chromosomes in an adaptive genetic algorithm (AGA) and used to optimize the bearing capacity of the tilting pad. The results show that the optimal method of the AGA, which has good stability and repeatability, remarkably improves the distribution of the slip zone on the surface of the inclined pad. Therefore, the bearing capacity of the liquid film is significantly improved. Particularly, by using the optimization, the boundary line between the slip/no-slip zone is a composite form of a part of an arc and a part of the whisker. When the liquid flow through the heterogeneous slip/on-slip surfaces is used by this composite splicing method, the liquid pressure is upgraded in two steps. This is more conducive to increasing the pressure on multiple areas on the surface of the tilting pad, thereby achieving higher bearing capacity.

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Model Based Analysis of Coupled Vibrations Due to the Combi-Bearing in Vertical Hydroturbogenerator Rotors

Journal of Vibration and Acoustics ◽

10.1115/1.4005002 ◽

2011 ◽

Vol 133 (6) ◽

Cited By ~ 4

Author(s):

Jean-Claude Luneno ◽

Jan-Olov Aidanpää ◽

Rolf Gustavsson

Keyword(s):

Thrust Bearing ◽

Hydrodynamic Pressure ◽

Fluid Film ◽

Machine Component ◽

Inertia Effects ◽

Tilting Pad ◽

Linearized Model ◽

Film Stiffness ◽

Assembly Error ◽

Model Based Analysis

The studies presented in this paper focus on analyzing how the combined thrust-journal bearing (commonly called combi-bearing) influences the dynamics of hydropower rotors. Thrust bearing is a component used in vertical rotating machinery and shafts designed to transmit thrust. The total axial load is carried by the single thrust bearing. Any design, manufacture, or assembly error in this component (thrust bearing) would certainly influence the functionality of the entire machine. The analyzed combi-bearing is an existing machine component used in the hydropower unit Porjus U9 situated in northern Sweden. This combi-bearing is a fluid-film lubricated tilting-pad thrust and journal bearings combined together. Only linear fluid-film stiffness was taken into account in the model while fluid-film damping and pads inertia effects were not taken into account. The linearized model shows that the combi-bearing couples the rotor’s lateral and angular motions. However, if the thrust bearing’s pads arrangement is not symmetrical or if all the pads are not angularly equidistant the rotor axial and angular motions are also coupled. This last case of coupling will also occur if the thrust bearing equivalent total stiffness is not evenly distributed over the thrust bearing. A defective pad or unequal hydrodynamic pressure distribution on the pads’ surfaces may be the cause. The Porjus U9’s simulation results show that the combi-bearing influences the dynamic behavior of the machine. The rotor motions’ coupling due to combi-bearing changes the system’s natural frequencies and vibration modes.

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Optimization of hydrodynamic lubrication performance based on a heterogeneous slip/no-slip surface

Industrial Lubrication and Tribology ◽

10.1108/ilt-07-2018-0268 ◽

2019 ◽

Vol 71 (6) ◽

pp. 772-778

Author(s):

Zhenpeng Wu ◽

Xianzhong Ding ◽

Liangcai Zeng ◽

Xiaolan Chen ◽

Kuisheng Chen

Keyword(s):

Friction Coefficient ◽

Liquid Film ◽

Bearing Capacity ◽

Slip Surface ◽

Hydrodynamic Lubrication ◽

Slip Zone ◽

Content Type ◽

Starting Point ◽

Lubrication Performance ◽

Residual Space

Purpose This paper aims to use the method of curve splicing to combine the slip zone and the no-slip zone to further improve the lubrication performance of the liquid film. The combination of the slip zone and the no-slip zone of an existing heterogeneous surface is still a single line stitching method so that a very large residual space at the surface of the friction pairs remains present, necessitating further improvement of the joining scheme between the slip zone and the no-slip zone in heterogeneous surfaces. Design/methodology/approach A set of discrete sinusoids is used as the splicing track for both the slip zone and the no-slip zone, the starting point and amplitude of the curve are introduced as the simulation variables and the effects of these variables on the bearing capacity and friction coefficient of the liquid film are comprehensively analyzed. Findings The results show that the method of selecting the sinusoidal curve as the slip zone and the no-slip zone trajectory, which is based on the existing method of linear stitching, can further enhance the bearing capacity and reduce the friction coefficient of the liquid film. Originality/value This method can further enhance the bearing capacity and reduce the friction coefficient of the liquid film.

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Centrally Pivoted Tilting Pad Thrust Bearing with Carbon-Based Coated Collar—Experimental Results of Low- and Medium-Speed Operation

Tribology Transactions ◽

10.1080/10402004.2015.1010761 ◽

2015 ◽

Vol 58 (5) ◽

pp. 882-893 ◽

Cited By ~ 7

Author(s):

Michal Wasilczuk ◽

Michal Wodtke ◽

Wolfgang Braun

Keyword(s):

Thrust Bearing ◽

Experimental Results ◽

Medium Speed ◽

Tilting Pad ◽

Carbon Based

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A new dynamic mesh algorithm for studying the 3D transient flow field of tilting pad journal bearings

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

10.1177/1350650116638610 ◽

2016 ◽

Vol 230 (12) ◽

pp. 1470-1482 ◽

Cited By ~ 6

Author(s):

Mengxuan Li ◽

Chaohua Gu ◽

Xiaohong Pan ◽

Shuiying Zheng ◽

Qiang Li

Keyword(s):

Flow Field ◽

Equilibrium Position ◽

Transient Flow ◽

Journal Bearings ◽

Dynamic Mesh ◽

Static Equilibrium ◽

Time Step ◽

Tilting Pad ◽

Grid Nodes ◽

Tilting Pad Journal Bearings

A new dynamic mesh algorithm is developed in this paper to realize the three-dimensional (3D) computational fluid dynamics (CFD) method for studying the small clearance transient flow field of tilting pad journal bearings (TPJBs). It is based on a structured grid, ensuring that the total number and the topology relationship of the grid nodes remain unchanged during the dynamic mesh updating process. The displacements of the grid nodes can be precisely recalculated at every time step. The updated mesh maintains high quality and is suitable for transient calculation of large journal displacement in FLUENT. The calculation results, such as the static equilibrium position and the dynamic characteristic coefficients, are consistent with the two-dimensional (2D) solution of the Reynolds equation. Furthermore, in the process of transient analysis, under conditions in which the journal is away from the static equilibrium position, evident differences appear between linearized and transient oil film forces, indicating that the nonlinear transient calculation is more suitable for studying the rotor-bearing system.

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On the Significance of the Inlet Pressure Build-Up in the Design of Tilting-Pad Bearings

Journal of Tribology ◽

10.1115/1.2920224 ◽

1990 ◽

Vol 112 (1) ◽

pp. 17-22 ◽

Cited By ~ 20

Author(s):

Cz. M. Rodkiewicz ◽

K. W. Kim ◽

J. S. Kennedy

Keyword(s):

Thrust Bearing ◽

Ambient Pressure ◽

Inlet Pressure ◽

Load Carrying Capacity ◽

Integral Theorem ◽

Lubricating Film ◽

Tilting Pad ◽

Load Carrying ◽

Momentum Integral ◽

Entrance Pressure

An operating tilting-pad thrust bearing generates a fore-region which is responsible for maintaining, at the bearing entrance, a pressure which is higher than the ambient pressure. This entrance pressure, in the presented analysis, is obtained by applying to the fore-region the momentum integral theorem. The solution of the lubricating film region is then obtained by using this modified inlet pressure. This solution yields the pressure distribution, the load carrying capacity, the film ratio and the frictional force for several values of the modified Reynolds number and various pivot positions. The analysis shows that there is a significant influence of the fore-region pressure on the bearing performance and that to properly design efficient tilting-pad bearing this effect should be taken into consideration.

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Discussion: “A Comparison of Tilting Pad Thrust Bearing Lubricant Supply Methods” (Mikula, A. M., and Gregory, R. S., 1983, ASME J. Lubr. Technol., 105, pp. 39–45)

Journal of Lubrication Technology ◽

10.1115/1.3254543 ◽

1983 ◽

Vol 105 (1) ◽

pp. 46-46

Author(s):

A. J. Leopard

Keyword(s):

Thrust Bearing ◽

Tilting Pad

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Analysis and performance of the gas lubricated tilting pad thrust bearing

Tribology ◽

10.1016/0041-2678(70)90046-1 ◽

1970 ◽

Vol 3 (1) ◽

pp. 58 ◽

Cited By ~ 1

Author(s):

W. Shapiro ◽

R. Colsher

Keyword(s):

Thrust Bearing ◽

Tilting Pad ◽

And Performance

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Discussion: “Experimental Comparison of Flooded, Directed, and Inlet Orifice Type of Lubrication for a Tilting Pad Thrust Bearing” (New, N. H., 1974, ASME J. Lubr. Technol., 96, pp. 22–26)

Journal of Lubrication Technology ◽

10.1115/1.3451901 ◽

1974 ◽

Vol 96 (1) ◽

pp. 27-27

Author(s):

A. B. Harbage

Keyword(s):

Thrust Bearing ◽

Experimental Comparison ◽

Tilting Pad

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A numerical method to investigate the mixed lubrication performances of journal-thrust coupled bearings

Industrial Lubrication and Tribology ◽

10.1108/ilt-02-2019-0063 ◽

2019 ◽

Vol 71 (9) ◽

pp. 1099-1107

Author(s):

Guo Xiang Guo Xiang ◽

Yanfeng Han ◽

Renxiang Chen ◽

Jiaxu Wang Jiaxu Wang ◽

Ni Xiaokang

Keyword(s):

Thrust Bearing ◽

Load Capacity ◽

Elastohydrodynamic Lubrication ◽

Hydrodynamic Pressure ◽

Mixed Lubrication ◽

Hydrodynamic Effect ◽

Asperity Contact ◽

Content Type ◽

Lubrication Regime ◽

Coupled Effect

Purpose This paper aims to present a numerical model to investigate the mixed lubrication performances of journal-thrust coupled bearings (or coupled bearings). Design/methodology/approach The coupled hydrodynamic effect (or coupled effect) between the journal and the thrust bearing is considered by ensuring the continuity of the hydrodynamic pressure and the flow field at the common boundary. The mixed lubrication performances of the coupled bearing are comparatively studied for the cases of considering and not considering coupled effect. Findings The simulated results show that the hydrodynamic pressure distributions for both the journal and thrust bearing are modified due to the coupled effect. The decreased load capacity of the journal bearing and the increased load capacity of the thrust bearing can be observed when the coupled effect is considered. And the coupled effect can facilitate in reducing the asperity contact load for both the journal and thrust bearing. Additionally, the interaction between the mixed lubrication behaviors, especially for the friction coefficient, of the journal and the thrust bearing is significant in the elastohydrodynamic lubrication regime, while it becomes weak in the mixed lubrication regime. Originality/value The developed model can reveal the mutual effects of the mixed lubrication behavior between the journal and the thrust bearing.

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