Effect of bearing materials on journal bearings under TEHL with lubricant based on Carreau model

The fatigue resistance of different bearing materials is usually given an “order of merit” in terms of specific load on the bearing. The bearing material cannot directly sense the applied specific load, since it is the hydrodynamic oil film pressures which directly create the stresses in the lining; both pressures and stresses need to be examined to see if a more meaningful criterion for fatigue can be found. As a first step in this study the experimental fatigue work carried out by Gyde at the University of Denmark was examined and compared with trends in peak specific load, hydrodynamic characteristics, and bearing lining stresses. It has been shown that peak specific load and peak hydrodynamic pressure are not in themselves realistic parameters, but that pressure variation on a bearing element, perhaps including some rapidly forming negative pressures, could be a significant term. The study of the more fundamental material stresses has not yet been extended to allow for the influence of any nonpositive film pressures, but results so far follow similar trends to those obtained on the pressure variation criterion.

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Running-in effects on friction of journal bearings under slow sliding speeds

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

10.1177/1350650119864758 ◽

2019 ◽

Vol 234 (3) ◽

pp. 362-372

Author(s):

A Linjamaa ◽

A Lehtovaara ◽

M Kallio ◽

A Léger

Keyword(s):

Journal Bearings ◽

Mixed Lubrication ◽

Bearing Material ◽

Environmentally Sustainable ◽

Tin Bronze ◽

Bearing Materials ◽

Stribeck Curves ◽

Remarkable Reduction ◽

Lubrication Conditions ◽

Film Lubrication

Hydrodynamic thrust and journal bearings are facing challenges in modern heavy-duty machinery where full film lubrication cannot always be achieved or sustained. This is due to reasons such as start–stop operation, increased power density and the use of thinner lubricants. Although this leads to increased overall efficiency, bearings are operating more often under mixed lubrication conditions. This is why the running-in behavior of the bearing material is important. In this study, running-in behavior of traditional leaded tin bronze and its environmentally sustainable alternative, bimetal bismuth, was studied. Experimental friction tests were performed with journal bearings under full film and mixed lubrication conditions in order to find the Stribeck curves. The results are analyzed using frictional energy, and friction coefficient values based on continuous friction monitoring. Remarkable reduction of friction was observed with both bearing materials due to running-in.

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The Application of Double Conical Journal Bearings in High Speed Centrifugal Pumps — Parts 1 and 2

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1975_189_030_02 ◽

1975 ◽

Vol 189 (1) ◽

pp. 221-230 ◽

Cited By ~ 4

Author(s):

C. Ettles ◽

O. Svoboda

Keyword(s):

Axial Load ◽

High Speed ◽

Load Capacity ◽

Correct Choice ◽

Journal Bearings ◽

Radial Load ◽

Centrifugal Pumps ◽

Half Angle ◽

Bearing Materials ◽

Flow Compensation

Conical bearings can in principle support a combination of radial and axial load. Their application to centrifugal pumps is considered, which allows the thrust bearing of the conventional arrangement to be dispensed with. It is shown that with low pressure oil lubrication, the axial load of this type of bearing is limited to the ratio (axial load/radial load)=Tan A, where A is the half angle of the cone. Methods of avoiding this limitation are considered. The feasibility of water lubricated inclined journal bearings for centrifugal pumps is analysed. A ‘Vee’ configuration double conical journal bearing is considered with a central high pressure feed from the pump outlet. Although the enhancement of viscosity due to turbulence is not as great as anticipated, the bearing is shown to have an adequate axial and radial load capacity. It is shown that flow compensation or restriction to each side of the bearing is necessary to maintain the escaped flow at an acceptable level. The limits of bearing operation are set by acceptable film thickness rather than excessive temperature rise. For this reason, the correct choice of bearing materials to run under thin film or no film conditions in the presence of dirt is probably more important than correct hydrodynamic design.

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Friction and Wear Characteristics of Bearing Materials Under Boundary Lubricated Conditions

Journal of Lubrication Technology ◽

10.1115/1.3453397 ◽

1979 ◽

Vol 101 (4) ◽

pp. 474-480

Author(s):

Yoshiki Doi ◽

Tutom Haba

Keyword(s):

Friction Coefficient ◽

Film Thickness ◽

Friction And Wear ◽

Journal Bearing ◽

Journal Bearings ◽

Load Parameter ◽

Empirical Equations ◽

Flash Temperature ◽

Bearing Materials ◽

Friction And Wear Characteristics

This paper presents the results of tests performed with journal bearings with seven bearing materials, at a variety of loads and rotational speeds. On the basis of these results some empirical equations for predicting the behavior of boundary lubricated journal bearings are proposed. It is demonstrated that a noncontact parameter, that is, the ratio of elastohydrodynamic film thickness to the combined roughness of the two mating surfaces, plays the same important role in the behavior of the boundary lubricated journal bearing as in rolling-sliding elements. The friction coefficient is represented by the noncontact parameter and a nondimensional load parameter, besides by material constants, unless preseizure occurs. A critical flash temperature can predict the preseizure. Moreover it is shown that the correlation between the specific wear and the friction coefficient is close at any operating condition.

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Challenges and Solutions of Recent Thick-Film Bearings (Keynote)

World Tribology Congress III, Volume 2 ◽

10.1115/wtc2005-64381 ◽

2005 ◽

Author(s):

Masato Tanaka

Keyword(s):

Thick Film ◽

Gas Turbines ◽

High Speed ◽

Hydrodynamic Lubrication ◽

Journal Bearings ◽

Design Tools ◽

Foil Bearings ◽

Bearing Materials ◽

Bearing Design ◽

Lubrication Models

Recent challenges and solutions are outlined and discussed for various thick-film bearings in this keynote address. What come into focus are large bearings for utility turbines, titling pad journal bearings for high speed rotating machinery, small bearings for turbochargers and HDD systems, automobile engine bearings and air-lubricated foil bearings for micro gas turbines. Depending on the challenges, different solutions are proposed, such as bearing design tools based on highly reliable hydrodynamic lubrication models, bearing materials for higher performance and less maintenance costs, and countermeasures for unstable shaft vibrations. Effective solutions have been given to some challenges, but not yet to the others. Tribologists are encouraged to pioneer new horizon in this field, defying hard routes.

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Improving soil remediation through characterization

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138300 ◽

1995 ◽

Vol 53 ◽

pp. 386-387

Author(s):

E. C. Buck ◽

N. L. Dietz ◽

J. K. Bates

Keyword(s):

Dust Particles ◽

Radiochemical Analysis ◽

Solid Product ◽

Uranium Contamination ◽

Physical Separation ◽

X Ray ◽

Rocky Flats ◽

Remediation Strategies ◽

Bearing Materials ◽

X Ray Absorption

Operations at former weapons processing facilities in the U. S. have resulted in a large volume of radionuclidecontaminated soils and residues. In an effort to improve remediation strategies and meet environmental regulations, radionuclide-bearing particles in contaminant soils from Fernald in Ohio and the Rocky Flats Plant (RFP) in Colorado have been characterized by electron microscopy. The object of these studies was to determine the form of the contaminant radionuclide, so that it properties could be established [1]. Physical separation and radiochemical analysis determined that uranium contamination at Fernald was not present exclusively in any one size/density fraction [2]. The uranium-contamination resulted from aqueous and solid product spills, air-borne dust particles, and from the operation of an incinerator on site. At RFP the contamination was from the incineration of Pu-bearing materials. Further analysis by x-ray absorption spectroscopy indicated that the majority of the uranium was in the 6+ oxidation state [3].

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