scholarly journals Hydrodynamic Lubrication of Journal Bearings by Pseudo-Plastic Lubricants : Part 1, Theoretical Studies

1970 ◽  
Vol 36 (287) ◽  
pp. 1183-1193 ◽  
Author(s):  
Sanae WADA ◽  
Hirotsugu HAYASHI
Keyword(s):  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Theoretical Studies ◽  
Plastic Lubricants

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.

scholarly journals Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 105 ◽  
Author(s):  
Maximilian Prölß ◽  
Hubert Schwarze ◽  
Thomas Hagemann ◽  
Philipp Zemella ◽  
Philipp Winking
Keyword(s):  
Experimental Data ◽  
Energy Equation ◽  
Hydrodynamic Lubrication ◽  
Frictional Coefficient ◽  
Journal Bearings ◽  
Numerical Code ◽  
Experimental Investigations ◽  
Lubrication Regime ◽  
Mixed Friction ◽  
Run Up

This paper focuses on the operating behavior of journal bearings for industrial machinery application during run-ups. For this purpose, a numerical simulation code that is based on a two-dimensional extended and generalized Reynolds equation and a full three-dimensional energy equation, was advanced by a theoretical model considering the effects of mixed friction and warming of journal components during start-up. The mixed friction routine contained the elastic half-spaces model proposed by Boussinesq, which considers the influence of rough surfaces by implementing flow factors and calculates additional stiffness and dissipation in areas with solid interactions. Furthermore, a transient term was added in the energy equation to consider the thermal inertia of journal, and bearing to ensure a realistic heating during run-ups. Results of the prediction were compared to experimental data taken from a special test rig built up for validation procedures. Besides the conventional sensors for temperature, oil flow, and relative motion between shaft and stator, a contact voltage measurement was installed to determine the intensity of mixed friction. The evaluation of experimental data by Stribeck curves, based on a shaft torsion measurement, indicated a significant influence of run-up time on frictional moment. The friction coefficient of the rotor bearing system was strongly influenced by the run-up time. A short run-up time reduced the frictional coefficient in the mixed lubrication regime while the opposite behavior was observed in the hydrodynamic lubrication regime. The numerical code predicted these tendencies in good agreement with experimental data, however, only if the transient energy model was applied.

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.

Experimental Investigation on PTFE Composites for Journal Bearings

2007 ◽  
Author(s):  
V. Jayaraj ◽  
K. Srinivasan
Keyword(s):  
Thin Film ◽  
Hydrodynamic Lubrication ◽  
Industrial Applications ◽  
Journal Bearings ◽  
Lubricating Oil ◽  
Lubricating Film ◽  
Ideal Situation ◽  
Rolling Element ◽  
Heavy Loads ◽  
Ptfe Composites

Journal bearings are widely used in many industrial applications. In journal bearings, under boundary lubricated conditions, the surfaces are considered to be technically dry or only slightly lubricated, so that the resistance to relative motion is due to the interaction between the highest asperities covered by the boundary film. A thin film of lubricating oil exists under this condition and there is partial metal to metal contact. The ideal situation where the two sliding surfaces are completely separated by a thin film of a viscous fluid or a gas is referred to as hydrodynamic lubrication. In hydrodynamic bearings, due to frequent starting and stopping, misalignment of the shaft with the bearing, application of heavy loads and unexpected sudden non flow of lubricant and such other service conditions result in boundary lubrication by squeezing out the lubricating film or allow the surface asperities to break through the film so that the shaft and bearing are pressed into contact with one another. The maximum wear occurs in fluid film bearings during boundary lubricated conditions. The use of dry bearings has therefore become more essential as it requires practically no lubricant to function. Moreover it is less expensive, resist contamination better compared to rolling element bearings and easier to design.

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