A Contact-Wear Model for the EHL Analysis of Engine Journal Bearings

2005 ◽  
Author(s):  
Ducai Wang
Keyword(s):  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Surface Profile ◽  
Journal Bearings ◽  
Bearing Surface ◽  
Wear Model ◽  
Contact Wear ◽  
Analysis Technique ◽  
Elastic Distortion ◽  
Account Interaction

Engine journal bearings are now routinely analysed using elasto-hydrodynamic lubrication (EHL) methods [1,2]. This analysis technique takes into account interaction of the hydrodynamic film with the elastic distortion produced in both the bearing and the journal. It has proved a robust analytic tool for designers in predicting the value and location of such parameters as minimum oil film thickness and maximum film pressure. However, for some very heavily loaded cases, the normal EHL analysis technique may fail to produce realistic solutions. Due to ‘cusping’ of the bearing surface under extreme pressures the edges of bearing may be predicted to penetrate the journal surface leading to a ‘negative’ film thickness. In reality, the surfaces will interact and a ‘running-in’ process will result in subtle changes to the bearing surface profile such that a hydrodynamic film can be maintained across the whole bearing surface. This study introduces a contact-wear model which attempts to model this situation.

Bearing profile of sliding tribological systems

2021 ◽  
pp. 53-56
Author(s):  
Keyword(s):  
Hydrodynamic Lubrication ◽  
Surface Profile ◽  
Experimental Methods ◽  
Hydrodynamic Characteristics ◽  
Bearing Surface ◽  
Tabular Data ◽  
Sliding Bearing ◽  
Friction Process ◽  
Operational Characteristics ◽  
Wide Range

The main contours of the bearing surfaces of friction pairs with hydrodynamic lubrication are considered. Analysis of tabular data and graphs obtained by experimental methods made it possible to establish additional parameters of influence on the hydrodynamic characteristics of the friction process and the operational characteristics of tribological systems, in a wide range of load-speed modes. Keywords: sliding bearing, hydrodynamics, bushing, bearing surface, profile, circle, ellipse, wavy contour, wear. [email protected]

Tilting-Pad Journal Bearings With Electronic Radial Oil Injection

1998 ◽  
Vol 120 (3) ◽  
pp. 583-594 ◽  
Author(s):  
I. F. Santos ◽  
F. H. Russo
Keyword(s):  
Hydrodynamic Lubrication ◽  
Hydrodynamic Forces ◽  
Journal Bearings ◽  
Theoretical Treatment ◽  
Bearing Surface ◽  
Static Behavior ◽  
Tilting Pad ◽  
Surface Active ◽  
Oil Injection ◽  
Tilting Pad Journal Bearings

This paper gives a theoretical treatment of the problem of journal bearings modeling connected to electronic oil injection into the bearing gap. The feasibility of influencing the static behavior of hydrodynamic forces by means of such oil injection is investigated. The lubricant is injected into the bearing gap by two mechanisms of lubrication: the conventional hydrodynamic lubrication and through orifices distributed along the bearing surface (active lubrication in the radial direction). By controlling the pressure of the oil injection, it is possible to get large variations in the active hydrodynamic forces; such effects could be useful for reducing vibrations in rotating machines.

Experimental Analysis of Journal Bearings

1995 ◽  
Vol 117 (3) ◽  
pp. 589-592 ◽  
Author(s):  
A. H. Elkholy ◽  
A. Elshakweer
Keyword(s):  
Film Thickness ◽  
Experimental Technique ◽  
Experimental Analysis ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Bearing Surface ◽  
General Outline ◽  
Modes Of Operation ◽  
Oil Film ◽  
Design Charts

This study presents a comprehensive technique, which could be applied to almost any rotating equipment to identify and diagnose journal bearing problems that relate to metal-to-metal bearing surface contact. Orbital measurements that describe bearing parameters in different modes of operation were experimentally obtained and analyzed. Such parameters may include: attitude angle, minimum oil film thickness, and the possibility of metal-to-metal rubbing occurrence. The general outline of the presented experimental technique was substantiated using the Raimondi–Boyd well-documented design charts and good correlation between experimental and analytical results was obtained.

An Investigation to the Effect of Elastic Deformations of the Bearing Surface of EP Air Bearings

2008 ◽  
Author(s):  
Anton van Beek ◽  
Ron van Ostayen ◽  
Rob Munnig Schmidt
Keyword(s):  
Film Thickness ◽  
Elastic Deformation ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Compressible Fluids ◽  
Air Bearings ◽  
Bearing Surface ◽  
Elasticity Equation ◽  
Elastic Distortion ◽  
3D Elasticity

In this paper a study is presented towards the effect of elastic deformation of the bearing surface of axial externally pressurized centrally pivoted modular air bearings. To this purpose shallow pocket, tapered and grooved air bearings are selected, which look the most promising to apply in small dimensions and with very small film thickness. The elastic deformation is calculated numerically by simultaneously solving the 2D-Reynolds equation for compressible fluids and the 3D-elasticity equation. The effect of the elastic distortion on the bearing performance is visualized in graphs presenting the load capacity and flow as a function of the film thickness. The results obtained from numerical calculation are verified experimentally.

scholarly journals Elastic hydrodynamic lubrication analysis for a sine movable tooth drive

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881410 ◽  
Author(s):  
Lizhong Xu ◽  
Wentao Song
Keyword(s):  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Normal Operation ◽  
Speed Ratio ◽  
Input Shaft ◽  
Load Carrying ◽  
Radial Dimension ◽  
Lubrication Condition ◽  
Shaft Rotation Angle ◽  
Large Speed

The sine movable tooth drive has small radial dimension such that the heat, caused by friction, becomes an important factor in deciding its load-carrying ability. It is important to determine the amount of tooth lubrication in order to reduce the heat caused by the friction. This study provides equations for the meshing performance and provides the forces for the sine movable tooth drive. Using these equations, the minimum oil film thickness for the drive system is investigated. Results show that the minimum film thickness between the movable tooth and input shaft or shell changes periodically along the input shaft rotation angle. A large movable tooth radius and a movable tooth rotation radius could increase the film thickness between the movable tooth and the input shaft or the shell. In addition, a large speed ratio could increase the film thickness between the movable tooth and the input shaft, but this would also decrease the film thickness between the movable tooth and the shell. A large sine amplitude could increase the film thickness between the movable tooth and the input shaft, but this does not change the film thickness between the movable tooth and the shell. Under normal operation speeds, the hydrodynamic lubrication condition occurs between the movable tooth and the input shaft, and the partial membrane hydrodynamic state occurs between the movable tooth and the shell.

scholarly journals Pulsating fields of a thin film in a static magnetic field under vertical vibrations

2021 ◽  
Vol 2103 (1) ◽  
pp. 012233
Author(s):  
I V Volodin ◽  
A A Alabuzhev
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Surface Wave ◽  
Film Thickness ◽  
Static Magnetic Field ◽  
Surface Profile ◽  
Vertical Vibration ◽  
Vibrational Amplitude ◽  
Gravitational Forces ◽  
Vertical Vibrations

Abstract In the present paper a dynamics of a thin ferrofluid film under the vertical vibration in a static magnetic field is examined. The vibrational amplitude is assumed to be greater than film thickness so that vibrational force is greater than magnetic and gravitational forces. The pulsating part and the averaged part of the hydrodynamics fields are obtained. The solution of pulsating part for the traveling surface wave is found. The equation for the averaged surface profile is found.

Hydrodynamic Lubrication and Wear in Wavy Contacting Face Seals

1978 ◽  
Vol 100 (1) ◽  
pp. 81-90 ◽  
Author(s):  
A. O. Lebeck ◽  
J. L. Teale ◽  
R. E. Pierce
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Lubrication ◽  
Surface Profile ◽  
Operating Conditions ◽  
Face Seal ◽  
Hydrodynamic Load ◽  
Surface Waviness ◽  
Wear Rates ◽  
Elastic Deflection ◽  
Face Seals

A model of face seal lubrication is proposed and developed. Hydrodynamic lubrication for rough surfaces, surface waviness, asperity load support, elastic deflection, and wear are considered in the model. Predictions of the ratio of hydrodynamic load support to asperity load support are made for a face seal sealing a low viscosity liquid where some contact does occur and surface roughness is important. The hydrodynamic lubrication is caused by circumferential surface waviness on the seal faces. Waviness is caused by initial out of flatness or any of the various distortions that occur on seal ring faces in operation. The equilibrium solution to the problem yields one dimensional hydrodynamic and asperity pressure distributions, mean film thickness, elastic deflection, and friction for a given load on the seal faces. The solution is found numerically. It is shown that the fraction of hydrodynamic load support depends on many parameters including the waviness amplitude, number of waves around the seal, face width, ring stiffness, and most importantly, surface roughness. For the particular seal examined the fraction of load support would be small for the amount of waviness expected in this seal. However, if the surface roughness were lower, almost complete lift-off is possible. The results of the analysis show why the initial friction and wear rates in mechanical face seals may vary widely; the fraction of hydrodynamic load support depends on the roughness and waviness which are not necessarily controlled. Finally, it is shown how such initial waviness effects disappear as the surface profile is altered by wear. This may take a long or short time, depending on the initial amount of hydrodynamic load support, but unless complete liftoff is achieved under all operating conditions, the effects of initial waviness will vanish in time for steady state conditions. Practical implications are drawn for selecting some seal parameters to enhance initial hydrodynamic load support without causing significant leakage.

Performance of Stern Tube Bearings under Different Lubrication and Operating Conditions

2009 ◽  
Author(s):  
Jan H. Andersen ◽  
Hiroyuki Sada ◽  
Seiji Yamajo
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Water Soluble ◽  
Analysis Tool ◽  
Test Rig ◽  
Experimental Performance ◽  
Shaft Alignment ◽  
Alignment Analysis

This paper presents the results of an investigation into the theoretical and experimental performance of oil lubricated journal bearings. DNV has developed a new calculation tool for the analysis of journal bearing performance as part of shaft alignment analysis. The results of the calculation tool have been compared to other research and analysis methods under static and dynamic conditions. In addition, white metal bearings were tested with decreasing Sommerfeld number until loss of hydrodynamic lubrication. The experiments were carried out in a bearing test rig and with three different lubricants, normal mineral oil, emulsifying oil, and water-soluble oil. The tests were done with increasing water content in the lubricant. Results from the test were compared with calculation using the DNV analysis tool.

A dynamic contact wear model of ball bearings without or with distributed defects

2020 ◽  
Vol 234 (24) ◽  
pp. 4827-4843
Author(s):  
Xi Zhang ◽  
Hua Xu ◽  
Wei Chang ◽  
Hui Xi ◽  
Shiyuan Pei ◽  
...  
Keyword(s):  
Dynamic Contact ◽  
Ball Bearings ◽  
Wear Model ◽  
Wear Rates ◽  
Contact Wear ◽  
Body Dynamics ◽  
Ball Diameter ◽  
Dynamic Wear ◽  
Multi Body ◽  
The Ideal

A dynamic contact wear model of ball bearings consisting of wear degree and position distribution is proposed by integrating the developed contact wear model, multi-body dynamics and raceway waviness or ball diameter differences. Subsequently, the dynamic wear characteristics, not only for the ideal bearing under different axial and radial loads, but also for the bearing with above defects are analysed. The influences of load, typical waviness orders and amplitude on the wear of each ball against both raceways are evaluated and qualitatively validated. Finally, the dynamic characteristics of ball bearings with one ball larger are discussed, and then vibration frequency and wear rates distinction are verified by the experiment with working-surface roughness measurement as a way for wear rate assessment.

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