Computer-Aided Study of Journal Bearings With Undulating Surfaces

1984 ◽  
Vol 106 (4) ◽  
pp. 468-472 ◽  
Author(s):  
M. O. A. Mokhtar ◽  
W. Y. Aly ◽  
G. S. A. Shawki
Keyword(s):  
Finite Length ◽  
Digital Computer ◽  
Wave Amplitude ◽  
Analytical Study ◽  
Journal Bearing ◽  
Numerical Solutions ◽  
Journal Bearings ◽  
Eccentricity Ratio ◽  
Load Line ◽  
Computer Aided

This paper presents the results of an analytical study of the performance of a cylindrical journal bearing of finite length as influenced by undulations intentionally produced on the surface. With the aid of a digital computer, the analysis has been applied to some common cases to obtain relevant numerical solutions. Compared with journal bearings having perfectly smooth surfaces, wavy bearings may well run at lower values of journal eccentricities and attitude angles. Wavy bearings may thus operate with higher safety. It is herein also established that, with load criterion as parameter, the higher the wave amplitude ac and the number of waves along the bearing circumference nc, the lower would be the eccentricity ratio. Moreover, when running at same eccentricity, higher values of ac and nc show a tendency of the journal center to move closer to the load line, thus leading to lower attitude angles.

An analytical study of the fluid film force in finite-length journal bearings. Part I

2001 ◽  
Vol 13 (4) ◽  
pp. 329-340 ◽  
Author(s):  
V. D'Agostino ◽  
D. Guida ◽  
A. Ruggiero ◽  
A. Senatore
Keyword(s):  
Finite Length ◽  
Analytical Study ◽  
Journal Bearings ◽  
Fluid Film

A Design of Coverage Area for Textured Surface of Sliding Journal Bearing Based on Genetic Algorithm

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Hui Zhang ◽  
Mahshid Hafezi ◽  
Guangneng Dong ◽  
Yang Liu
Keyword(s):  
Genetic Algorithm ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Textured Surface ◽  
The Novel ◽  
Eccentricity Ratio ◽  
Coverage Area ◽  
Elliptical Shape ◽  
Bearing Load ◽  
Rectangular Grids

This paper aims to improve the tribological performance of journal bearings by optimizing the coverage area of circular microtextures in divergent region of the sleeve. A numerical model is proposed to calculate the friction coefficient and bearing load of textured journal bearings. The surface of the sleeve is divided into rectangular squares. Textures that located at the center of rectangular grids are assumed to be present or absent, marked as 1 and 0, respectively. Afterward, different texture coverage area arrangements are evolved and selected based on the genetic algorithm (GA). The area of semi-elliptical shape is obtained as the novel and preferable textured coverage area design for journal bearings. Influences of width and eccentricity ratio are discussed, which confirm the semimajor and semiminor axes of the semi-elliptical shape of texture coverage area equal to one-third of the circumferential length and half of the width of the journal bearing, respectively.

The Influence of Fluid Inertia on the Dynamic Properties of Journal Bearings

1975 ◽  
Vol 97 (2) ◽  
pp. 159-165 ◽  
Author(s):  
E. Reinhardt ◽  
J. W. Lund
Keyword(s):  
Journal Bearing ◽  
Dynamic Properties ◽  
Journal Bearings ◽  
Graphical Form ◽  
Inertial Forces ◽  
Virtual Mass ◽  
Fluid Inertia ◽  
Eccentricity Ratio ◽  
First Order ◽  
First Order Perturbation

Based on a first-order perturbation solution in a modified Reynolds number an analysis is presented to determine the effect of the fluid film inertial forces on the dynamic properties of a journal bearing. The corrections to the regular amplitude and velocity coefficients are found to be small, but the accompanying acceleration coefficients which may correspond to a virtual mass of several times the mass of the journal itself, could become significant for short rotors. Numerical results are given in graphical form with dimensionless coefficients as functions of the operating eccentricity ratio.

HYDRODYNAMIC CHARACTERISTICS OF ER FLUID FLOWS IN JOURNAL BEARINGS

2003 ◽  
Vol 17 (01n02) ◽  
pp. 205-208 ◽  
Author(s):  
KE-QIN ZHU ◽  
JIE PENG
Keyword(s):  
Electric Field ◽  
Journal Bearing ◽  
Fluid Flows ◽  
Journal Bearings ◽  
Hydrodynamic Characteristics ◽  
Eccentricity Ratio ◽  
High Eccentricity ◽  
Bingham Plastic ◽  
Er Fluids ◽  
Er Fluid

A numerical analysis is performed on the hydrodynamic characteristics of electrorheological(ER) fluid flows in journal bearings based on the basic hydrodynamic equations. The flow field is assumed to be incompressible and isotropic, the Bingham plastic model is used to describe the behavior of ER fluids. The effect of bearing eccentricity ratio and applied electric field intensity has been studied attentively. It shows that control of the journal bearing through external electric field is much more feasible in high eccentricity ratio bearing than in low eccentricity ratio one.

THD Analysis of High Speed Heavily Loaded Journal Bearings Including Thermal Deformation, Mass Conserving Cavitation, and Turbulent Effects

1999 ◽  
Vol 122 (3) ◽  
pp. 597-602 ◽  
Author(s):  
Chao Zhang ◽  
Zixia Yi ◽  
Zhiming Zhang
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
High Speed ◽  
Thermal Deformation ◽  
Numerical Solutions ◽  
Journal Bearings ◽  
Eccentricity Ratio ◽  
Temperature Distributions ◽  
Theoretical Results

Theoretical and experimental THD analyses of high speed heavily loaded journal bearings are presented. Numerical solutions include thermal deformation, mass conserving cavitation and turbulent effects. The pressure and temperature distributions, the eccentricity ratio, and the flow rate are measured. Agreement between theoretical results and experimental data is satisfactory. [S0742-4787(00)00803-1]

Gas-Lubricated Cylindrical Journal Bearings of the Finite Length: Static Loading

1961 ◽  
Vol 28 (4) ◽  
pp. 535-543 ◽  
Author(s):  
B. Sternlicht
Keyword(s):  
Finite Length ◽  
Static Loading ◽  
Reynolds Equation ◽  
Numerical Solutions ◽  
Journal Bearings ◽  
First Order ◽  
Advantages And Disadvantages ◽  
Iterative Solutions ◽  
Constant Magnitude ◽  
First Order Perturbation

This paper presents numerical solutions of the Reynolds equation for finite length, gas-lubricated cylindrical journal bearings under static loading (this corresponds to a load of constant magnitude and direction with respect to the bearing). It is shown that the incompressible results are but only limiting cases to the more general compressible solutions. The results of the two solutions are dovetailed together through the use of two dimensionless parameters: the inverse of the Sommerfeld number and the compressibility number. Comparisons of the iterative solutions and the first-order perturbation and the “linearized ph” methods are made. The advantages and disadvantages of these methods of analysis are discussed.

The Load Capacity of Short Journal Bearings With Oscillating Effective Speed

1964 ◽  
Vol 86 (2) ◽  
pp. 348-353 ◽  
Author(s):  
B. K. Gupta ◽  
R. M. Phelan
Keyword(s):  
Significant Contribution ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Numerical Solutions ◽  
Load Capacity ◽  
Journal Bearings ◽  
Squeeze Film ◽  
Major Conclusion ◽  
Angular Velocities ◽  
Effective Speed

The development of the Reynolds equation for the general case of dynamically loaded journal bearings is extended to include the concept of an effective speed that combines in one term the angular velocities of the journal, bearing, and load. Numerical solutions for the short-bearing approximation are presented for the case of an oscillating effective speed and a load that is constant or varying sinusoidally. Results are compared with available experimental data. The major conclusion is that for those cases involving an oscillating effective speed and a reversing load, the only significant contribution to load capacity comes from the squeeze film and the wedge film can safely be ignored when designing such bearings.

On the Performance of Journal Bearings Under Conditions of Film Rupture, Part II

1975 ◽  
Vol 97 (4) ◽  
pp. 591-598
Author(s):  
W. A. Crosby ◽  
E. M. Badawy
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Finite Length ◽  
Infinite Number ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Operating Characteristics ◽  
Film Rupture ◽  
Rupture Part

An analytical analysis of journal bearing performance under conditions of film rupture by separation and by cavitation is performed. The ruptured region is considered to have an infinite number of cavities. The boundary condition of Reynolds’ equation at the trailing edge is influenced by the bearing’s operating characteristics and the method of oil admission. A variational solution is given in order to extend the applicability of the boundary conditions to bearings of finite length.

A Sommerfeld Solution for Finite Bearings With Circumferential Grooves

1960 ◽  
Vol 82 (2) ◽  
pp. 321-326 ◽  
Author(s):  
J. V. Fedor
Keyword(s):  
Differential Equation ◽  
Excellent Agreement ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Algebraic Complexity ◽  
Eccentricity Ratio ◽  
Finite Form ◽  
Oil Film ◽  
Method Of Solution ◽  
Friction Curve

A method of solution is developed that circumvents the algebraic complexity in the solution of Reynolds differential equation applied to full journal bearings. The method leads to equations for journal-bearing characteristics that are in finite form. Salient features of the complete-oil-film solution are: As the eccentricity ratio b approaches 1, the load capacities of all finite bearings approach that of the infinite bearing; also, the friction curve intercept, (r/c)f, is 1 for all finite bearings when b equals 1. Results are compared with calculated values published by Muskat and Morgan for 0 < b < 0.6. Excellent agreement is found throughout the compared range.

Mobility and Impedance Definitions for Plain Journal Bearings

1981 ◽  
Vol 103 (3) ◽  
pp. 468-470 ◽  
Author(s):  
H. Moes ◽  
R. Bosma
Keyword(s):  
Finite Length ◽  
Journal Bearing ◽  
Journal Bearings

A list of mobility and impedance definitions is given for a set of full-journal-bearing solutions, including the finite-length-bearing solution.

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