scholarly journals Effects of velocity-slip and viscosity variation on journal bearings

2004 ◽  
Vol 46 (1) ◽  
pp. 143-155 ◽  
Author(s):  
R. Raghavendra Rao ◽  
K. R. Prasad
Keyword(s):  
Boundary Conditions ◽  
Coefficient Of Friction ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Velocity Slip ◽  
Journal Bearings ◽  
Viscous Layer ◽  
The Coefficient Of Friction ◽  
Viscosity Variation

AbstractA generalised form of the Reynolds equation for two symmetrical surfaces is derived by considering slip at the bearing surfaces. This equation is then used to study the effects of velocity-slip for the lubrication of journal bearings using half-Sommerfeld boundary conditions. Expressions for pressure and load capacity and the coefficient of friction are obtained and numerically analysed for various parameters. It is found that the load capacity decreases with slip. This is unfavourable for lubrication. The coefficient of friction decreases with a high viscous layer and increases with slip.

Spiral Bearing Lubrication with Viscosity Variation And Thermal Effect of Two Layer Fluid

2017 ◽  
Vol 6 (5) ◽  
Author(s):  
M. Ganapathi ◽  
S. Vijayakumarvarma ◽  
K.R.K. Prasad ◽  
Bharath Kumar
Keyword(s):  
Thermal Effect ◽  
Layer Thickness ◽  
Coefficient Of Friction ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Load Factor ◽  
Load Pressure ◽  
Viscosity Variation ◽  
Generalized Reynolds Equation

In this paper a fluid film equation for two layer fluids and generalized Reynolds equation for convergent and divergent spiral bearing is derived with thermal effect. It is applied to see the effect of pre-load factor, viscosity variation, eccentricity, peripheral layer thickness. Expressions for load, pressure and coefficient of friction are derived and are analyzed numerically. The effect of pre-load factor analyzed for convergent and divergent spiral bearings. When pre-load factor is zero then both convergent and divergent spiral bearings are becomes journal bearing. It is observed the dimensionless load capacity values form the tables. The spiral bearing bears more load capacity than journal bearing. The effects of viscosity variation and thermal effect on these parameters are also analyzed.

Analysis of Two-Layered Film Journal Bearing with Partial Slip Surface

2014 ◽  
Vol 903 ◽  
pp. 215-220 ◽  
Author(s):  
T.V.V.L.N. Rao ◽  
A.M.A. Rani ◽  
T. Nagarajan ◽  
F.M. Hashim
Keyword(s):  
Boundary Conditions ◽  
Coefficient Of Friction ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Slip Surface ◽  
Load Capacity ◽  
Partial Slip ◽  
Navier Slip ◽  
Navier Slip Boundary Conditions ◽  
Modified Reynolds Equation

Based on the approach of two-layered film consisting of different Newtonian viscosities, the present study examines the effects of partial slip bearing configuration on load capacity and friction coefficient for journal bearing. Navier slip boundary conditions are used to analyze partial slip configuration. A modified Reynolds equation for a journal bearing with two-layered film on a partial slip surface is presented. The modified Reynolds equation is derived taking into consideration of magnitude of lubricant layers film thickness, viscosities and the extent of partial slip on the bearing surface. The Reynolds boundary conditions are used in the analysis to predict nondimensional load capacity and coefficient of friction. Partial slip of bearing surfaces has a potential to improve load carrying capacity and reduce coefficient of friction for two-layered film journal bearing.

Hybrid Porous Gas Journal Bearings: Steady State Solution Incorporating the Effect of Velocity Slip

1984 ◽  
Vol 106 (3) ◽  
pp. 322-328 ◽  
Author(s):  
K. C. Singh ◽  
N. S. Rao ◽  
B. C. Majumdar
Keyword(s):  
Steady State ◽  
Reynolds Equation ◽  
Stokes Equations ◽  
Load Capacity ◽  
Velocity Slip ◽  
Steady State Solution ◽  
Static Characteristic ◽  
Journal Bearings ◽  
Mass Rate ◽  
Modified Reynolds Equation

A theoretical analysis is presented to predict the steady state performance characteristics of externally pressurized rotating gas journal bearings incorporating the effect of velocity slip at the porous interface. The governing equation for flow in the porous media and the modified Reynolds equation derived from the Navier-Stokes equations satisfying the velocity slip boundary condition, are solved simultaneously for film pressure distribution. Due to the nonlinearity of modified Reynolds equation the solution is obtained by perturbation method using finite difference technique. The dimensionless load capacity, attitude angle and mass rate of flow are computed numerically for different operating parameters. The effect of slip on the static characteristic is discussed. Comparison of the results with similar available solution for the no-slip case shows good agreement.

Calculation of Cylindrical Worm Gear Drives of Different Tooth Profiles

1981 ◽  
Vol 103 (1) ◽  
pp. 73-82 ◽  
Author(s):  
H. Winter ◽  
H. Wilkesmann
Keyword(s):  
Coefficient Of Friction ◽  
Theoretical Basis ◽  
Power Loss ◽  
Influence Factor ◽  
Load Capacity ◽  
Worm Gear ◽  
Important Influence ◽  
Test Results ◽  
The Coefficient Of Friction ◽  
Gear Drives

The formulae of classical hydrodynamics are not suitable for the calculation of load capacity and power loss of worm gear drives. Thus a theoretical basis had to be developed for the comparison of different tooth profiles, materials of worm and worm wheel and lubricants. The data obtained were compared with test results. It proved that the coefficient of friction is an important influence factor.

Lubrication of Porous Journal Bearings

1972 ◽  
Vol 94 (1) ◽  
pp. 69-73 ◽  
Author(s):  
C. Cusano
Keyword(s):  
Analytical Solution ◽  
Coefficient Of Friction ◽  
Load Capacity ◽  
Journal Bearings ◽  
Performance Characteristics ◽  
Eccentricity Ratio ◽  
Design Variables

An analytical solution for the performance characteristics of finite porous journal bearings is obtained. Results are presented which relate the eccentricity ratio and coefficient of friction as functions of load number for design variables of 0.0001, 0.001, 0.01, and 0.1. The load capacity obtained by using the finite bearing theory is compared to the load capacity obtained by using the short-bearing approximation and the infinite-bearing approximation.

Effect of velocity slip in a narrow rough porous journal bearing

2003 ◽  
Vol 217 (1) ◽  
pp. 59-70 ◽  
Author(s):  
K Gururajan ◽  
J Prakash
Keyword(s):  
Porous Material ◽  
Coefficient Of Friction ◽  
Strong Interaction ◽  
Journal Bearing ◽  
Load Capacity ◽  
Tangential Velocity ◽  
Velocity Slip ◽  
Qualitative And Quantitative ◽  
Slip Effects ◽  
Thin Walled

The paper examines the effect of velocity slip in a thin-walled infinitely short rough porous journal bearing operating under steady conditions in a hydrodynamic regime. The analysis extends earlier work [1] in which the tangential velocity at the surface of the porous material was neglected. The problem is solved analytically together with associated boundary conditions. It is found that there exists a strong interaction between roughness and slip effects. A comparison with the case of an infinitely long journal bearing [2] shows that there are significant qualitative and quantitative differences in load capacity and coefficient of friction. However, the slip-induced variations in friction force are similar to those for an infinitely long journal bearing.

Simulating Torsional Slip in V-Band Clamp Joints

2015 ◽  
Vol 798 ◽  
pp. 53-58
Author(s):  
Salahaddin M. Sahboun ◽  
Simon M. Barrans
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Load Capacity ◽  
Contact Region ◽  
Finite Element Technique ◽  
Torsional Load ◽  
V Band ◽  
The Coefficient Of Friction ◽  
Element Technique

In this paper a finite element technique to predict the torsional load capacity of V-band clamp joints is presented. The development of this complex, multi-step analysis is explained and the results compared with alternate theories which ignore or take account of transverse friction in the band to flange contact region. It is shown that accounting for transverse friction yields a better comparison with the finite element results for lower coefficients of friction whilst ignoring this component gives better results for higher coefficients of friction. Torsional load capacity is shown to increase with band diameter and T-bolt tension but to be less dependent on the coefficient of friction.

Empirical Treatment of Hydrodynamic Journal Bearing Performance in the Superlaminar Regime

1970 ◽  
Vol 12 (2) ◽  
pp. 116-122 ◽  
Author(s):  
H. F. Black
Keyword(s):  
Reynolds Number ◽  
Field Equation ◽  
Experimental Work ◽  
Reynolds Equation ◽  
Pressure Field ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Theoretical Treatment ◽  
Hydrodynamic Journal Bearing

The application of a perturbation in terms of simple correlations for friction in turbulent Couette and ‘screw’ flows, together with a further empirical assumption consonant with the experimental work of Smith and Fuller (1), leads to a pressure field equation identical in form with the Reynolds equation. The load capacity of journal bearings throughout most of the superlaminar range may be represented by a single curve, and existing laminar solutions may be applied with the parameters modified by Reynolds number. The theory is compared with published experimental results, and with the most successful theoretical treatment (4). The correlations obtained confirm the adequacy of the theory to predict performance in the superlaminar régime.

On the linear stability analysis of finite-hydrodynamic porous journal bearings under coupled stress lubrication

2007 ◽  
Vol 221 (7) ◽  
pp. 831-840 ◽  
Author(s):  
S. K. Guha ◽  
A. K. Chattopadhyay
Keyword(s):  
Reynolds Equation ◽  
Dynamic Performance ◽  
Slip Flow ◽  
Tangential Velocity ◽  
Continuum Theory ◽  
Transient State ◽  
Velocity Slip ◽  
Journal Bearings ◽  
The Stability ◽  
Coupled Stress

The objective of the present investigation is to study theoretically, using the finite-difference techniques, the dynamic performance characteristics of finite-hydrodynamic porous journal bearings lubricated with coupled stress fluids. In the analysis based on the Stokes micro-continuum theory of the rheological effects of coupled stress fluids, a modified form of Reynolds equation governing the transient-state hydrodynamic film pressures in porous journal bearings with the effect of slip flow of coupled stress fluid as lubricant is obtained. Moreover, the tangential velocity slip at the surface of porous bush has been considered by using Beavers-Joseph criterion. Using the first-order perturbation of the modified Reynolds equation, the stability characteristics in terms of threshold stability parameter and whirl ratios are obtained for various parameters viz. permeability factor, slip coefficient, bearing feeding parameter, and eccentricity ratio. The results show that the coupled stress fluid exhibits better stability in comparison with Newtonian fluid.

scholarly journals Mathematical Model and Analysis of the Water-Lubricated Hydrostatic Journal Bearings considering the Translational and Tilting Motions

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Hui-Hui Feng ◽  
Chun-Dong Xu ◽  
Jie Wan
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Journal Bearings ◽  
Linear Perturbation ◽  
Eccentricity Ratio ◽  
Dynamic Coefficients ◽  
Pressure Fields ◽  
Dynamic Performances ◽  
Rotary Speed

The water-lubricated bearings have been paid attention for their advantages to reduce the power loss and temperature rise and increase load capacity at high speed. To fully study the complete dynamic coefficients of two water-lubricated, hydrostatic journal bearings used to support a rigid rotor, a four-degree-of-freedom model considering the translational and tilting motion is presented. The effects of tilting ratio, rotary speed, and eccentricity ratio on the static and dynamic performances of the bearings are investigated. The bulk turbulent Reynolds equation is adopted. The finite difference method and a linear perturbation method are used to calculate the zeroth- and first-order pressure fields to obtain the static and dynamic coefficients. The results suggest that when the tilting ratio is smaller than 0.4 or the eccentricity ratio is smaller than 0.1, the static and dynamic characteristics are relatively insensitive to the tilting and eccentricity ratios; however, for larger tilting or eccentricity ratios, the tilting and eccentric effects should be fully considered. Meanwhile, the rotary speed significantly affects the performance of the hydrostatic, water-lubricated bearings.

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