Oscillating Journal Bearings Under Steady Load: A Numerical Study of Limiting Cases

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
S. Boedo ◽  
D. P. Anderson
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Journal Bearing ◽  
Numerical Study ◽  
Substantial Improvement ◽  
Journal Bearings ◽  
Method Of Solution ◽  
Mobility Method ◽  
Zero Offset ◽  
Steady Load

This note provides a more extensive assessment of bearing performance for steadily loaded oscillating journal bearings using the mobility method of solution. Even with significantly large journal oscillation amplitudes, unexpectedly thin films are predicted for conventional designs as the load number goes to zero. Offset journal bearing arrangements subjected to the same loads and kinematics are shown to provide a substantial improvement in film thickness, particularly at low oscillation amplitudes, compared with the conventional design configuration.

Analytical Curve Fits for Solution Parameters of Dynamically Loaded Journal Bearings

1984 ◽  
Vol 106 (4) ◽  
pp. 421-427 ◽  
Author(s):  
P. K. Goenka
Keyword(s):  
Journal Bearing ◽  
Journal Bearings ◽  
Solution Time ◽  
Pressure Curve ◽  
Element Analysis ◽  
Analytical Curve ◽  
Dynamically Loaded ◽  
Method Of Solution ◽  
Mobility Method ◽  
Solution Accuracy

The mobility method of solution is frequently used for analyzing dynamically loaded journal bearings. Curve fits of journal-bearing solutions are used in this method. All the currently available curve fits are lacking in one or more of three important features—the solution accuracy, the solution detail, and the solution time. A new set of analytical curve fits is presented in this paper. The set includes: the two components of mobility vectors, location and magnitude of maximum film pressure, and the starting and finishing angles of the pressure curve. For an ideal journal bearing, the new curve fits give accuracy and solution detail comparable to an expensive finite-element analysis, while keeping the solution time comparable to that required for the short-bearing approximation. An example is presented to demonstrate the use of the new curve fits.

Combined Influence of Misalignment and Orifice Diameter on the Static Performances of Hydrostatic, Water-Lubricated Journal Bearings

2014 ◽  
Vol 607 ◽  
pp. 608-611
Author(s):  
Hui Hui Feng ◽  
Chun Dong Xu ◽  
Feng Feng Wang
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Film Thickness ◽  
Power Loss ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Orifice Diameter ◽  
Rigid Rotor ◽  
Static Performance

The water-lubricated bearings have gained an increasing focus to overcome the disadvantages of the oil film bearings and gas bearings. In this paper, the influences of orifice diameter in aligned and misaligned conditions on the static performance of two hydrostatic, four-recess, water-lubricated journal bearings used to support a rigid rotor, are investigated. The steady Reynolds equation for the journal bearing for the turbulent bulk flow and the film thickness expression considering tilting angles are used and numerically solved by finite difference method. Results demonstrate that the static performances, such as the quality, power loss and temperature rise are affected by the tilting angles, orifice diameter to some degree.

Dynamically Loaded Journal Bearings: Mobility Method of Solution

1965 ◽  
Vol 87 (3) ◽  
pp. 537-546 ◽  
Author(s):  
J. F. Booker
Keyword(s):  
Numerical Solutions ◽  
Journal Bearings ◽  
Dynamically Loaded ◽  
Method Of Solution ◽  
Mobility Method

An approach is presented for simplified analytical, graphical, and numerical solutions to extremely general problems of dynamically loaded bearings. A series of examples illustrates the application of the method to problems of varying complexity.

Research on the Static and Dynamic Characteristics of Misaligned Journal Bearing Considering the Turbulent and Thermohydrodynamic Effects

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Guohui Xu ◽  
Jian Zhou ◽  
Haipeng Geng ◽  
Mingjian Lu ◽  
Lihua Yang ◽  
...  
Keyword(s):  
Film Thickness ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Static And Dynamic Characteristics ◽  
Oil Film ◽  
Stiffness And Damping ◽  
Film Stiffness ◽  
Journal Misalignment ◽  
Oil Film Pressure

Journal misalignment usually exists in journal bearings that affect nearly all the bearings static and dynamic characteristics including minimum oil film thickness, maximum oil film pressure, maximum oil film temperature, oil film stiffness, and damping. The main point in this study is to provide a comprehensive analysis on the oil film pressure, oil film temperature, oil film thickness, load-carrying capacity, oil film stiffness, and damping of journal bearing with different misalignment ratios and appropriately considering the turbulent and thermo effects based on solving the generalized Reynolds equation and energy equation. The results indicate that the oil thermo effects have a significant effect on the lubrication of misaligned journal bearings under large eccentricity ratio. The turbulent will obviously affect the lubrication of misaligned journal bearings when the eccentricity or misalignment ratio is large. In the present design of the journal bearing, the load and speed become higher and higher, and the eccentricity and misalignment ratio are usually large in the operating conditions. Therefore, it is necessary to take the effects of journal misalignment, turbulent, and thermal effect into account in the design and analysis of journal bearings.

scholarly journals Numerical Analysis of a Hydrodynamic Herringbone Grooved Journal Bearing

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
D. Souchet ◽  
A. Senouci ◽  
H. Zaidi ◽  
M. Amirat
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Numerical Study ◽  
Hydrodynamic Lubrication ◽  
Dynamical Behavior ◽  
Axial Flow ◽  
Journal Bearings ◽  
Film Rupture ◽  
High Rotational Speed ◽  
Fluid Leakage

In hydrodynamic lubrication, at very high rotational speed, the phenomenon of axial fluid leakage is often present. This can involve an increase of shear stress in the contact and consequently a considerable increase of the temperature. For that and in order to solve this problem, we took interest in the herringbone grooved journal bearings. The researches made before on these types of groove bearing have shown that they present a good dynamical behavior with a low eccentricity and a low axial flow. In this paper, a numerical study of a herringbone journal bearing operating behavior, under laminar and isothermal regime, is presented. The theoretical model, based on the classical Reynolds equation, is used. In order to include the film rupture and reformation, the Reynolds equation is modified using a mass conservative algorithm. To understand the behavior of these herringbone grooved journal bearings well, numerical modeling, using finite element method, has been developed. Various geometrical shapes of the herringbone grooved journal bearings have been analyzed, allowing us to limit the fluid leakage problem, by working particularly on the contact form.

Report 5: An Optical Method of Measuring Film Thickness

1967 ◽  
Vol 182 (7) ◽  
pp. 56-58
Author(s):  
G. R. Higginson ◽  
S. Reed
Keyword(s):  
Film Thickness ◽  
Optical Method ◽  
Journal Bearing ◽  
Lubricant Film ◽  
Parallel Surfaces ◽  
Steady Load ◽  
Local Value

This report describes a method which is being developed specifically to measure the film thickness in a journal bearing carrying a steady load. In such a bearing the lubricant film is essentially parallel and its area very large. The requirement therefore is for a method which will measure a local value of the distance between two curved but parallel surfaces about 10 μ apart. The optical method described below can be used either in transmission with two transparent bodies or in reflection with one transparent and one opaque. In the intended applications the reflection technique will be used, with a semi-reflecting layer on the surface of the transparent body.

scholarly journals Numerical Study of a Journal Bearing with Scratches: Validation with Literature and Comparison with Experimental Data

Lubricants ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 61
Author(s):  
Anh T. Vo ◽  
Michel Fillon ◽  
Jean Bouyer
Keyword(s):  
Scientific Literature ◽  
Journal Bearing ◽  
Numerical Study ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Test Rig ◽  
Numerical Studies ◽  
Clear Idea ◽  
Volume Method ◽  
Good Agreement

The lifespan of journal bearings is directly related to the operating conditions they have to face and reducing their maintenance intervals allows one to have a clear idea about their performance when issues occur. The presence of scratches on one of its surfaces degrades the performance of a journal bearing. These effects have already been assessed in experiments; however, numerical studies on this subject are still scarce. This work develops a numerical thermohydrodynamic (THD) program using the finite volume method to simulate the effects of scratches on the performance of journal bearings. To test the validity of the program, the numerical results are compared with the scientific literature and with experimental measurements conducted using the Pprime Institute journal bearing test rig. Some minor discrepancies are observed, but the overall results are in good agreement.

Improvement of the THD Performance of a Misaligned Plain Journal Bearing

2003 ◽  
Vol 125 (2) ◽  
pp. 334-342 ◽  
Author(s):  
J. Bouyer ◽  
M. Fillon
Keyword(s):  
Film Thickness ◽  
Flow Rate ◽  
Journal Bearing ◽  
Numerical Study ◽  
Axial Flow ◽  
Hydrodynamic Pressure ◽  
Operating Conditions ◽  
Local Defect ◽  
Minimum Film Thickness ◽  
Global Defect

This numerical study deals with the improvement of the thermohydrodynamic performance of a 100 mm plain journal bearing submitted to a constant misalignment torque under steady-state conditions. The performance of the misaligned journal bearing is improved by adding either a local or a global defect to the bearing geometry. The influence on bearing performance of the local defect, situated in the zone of minimum film thickness, is analyzed by using various widths and lengths of defect. A global defect, which is conical in shape and is located at one end of the bearing, is also studied under varying direction and magnitude of misalignment torque. Our main focus was on hydrodynamic pressure, temperature distributions at the film/bush interface, oil flow rate, power losses and film thickness. The defects significantly improved the performance of the bearing. The minimum film thickness increased by more than 60 percent and the temperature decreased, whilst the axial flow rate was barely affected. Thus, the defects can be an effective solution for misaligned bearings when they are submitted to extreme operating conditions.

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