A study of a journal bearing lubricated by couple stress fluids considering thermal and cavitation effects

2002 ◽  
Vol 216 (5) ◽  
pp. 293-305 ◽  
Author(s):  
X-L Wang ◽  
K-Q Zhu ◽  
C-L Gui
Keyword(s):  
Couple Stress ◽  
Heat Conduction Equation ◽  
Reynolds Equation ◽  
Energy Equation ◽  
Theoretical Study ◽  
Journal Bearing ◽  
Fluid Model ◽  
Load Capacity ◽  
Modified Reynolds Equation ◽  
Couple Stress Fluids

A theoretical study of a finite grooved journal bearing lubricated with couple stress fluids is made considering both thermal and cavitation effects. On the basis of the Stokes couple stress fluid model, the modified Reynolds equation and the energy equation are derived and then numerically solved together with the heat conduction equation. The solution to the modified Reynolds equation is determined using the Elrod cavitation algorithm. The effects of couple stress on the performance of a journal bearing are investigated. It is observed that the lubricants with couple stress, compared with Newtonian lubricants, not only yield an obvious increase in load capacity and decrease in coefficient of friction but also produce a slight increase in the temperature of lubricants and bush and a slight decrease in the side leakage flow.

scholarly journals Surface roughness effect on thermohydrodynamic analysis of journal bearings lubricated with couple stress fluids

2019 ◽  
Vol 8 (1) ◽  
pp. 397-406 ◽  
Author(s):  
Vishwanath B. Awati ◽  
Ashwini Kengangutti
Keyword(s):  
Surface Roughness ◽  
Couple Stress ◽  
Reynolds Equation ◽  
Multigrid Method ◽  
Energy Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Roughness Effect ◽  
Hydrodynamic Analysis

Abstract The paper presents, surface roughness effect for thermo-hydrodynamic analysis of journal bearings extended to couple stress lubricants with high polymer additives. A modified energy equation is simultaneously solved with heat transfer equation as well as modified Reynolds equation by using Multigrid method. The effects of couple stress and surface roughness on the performances of a finite journal bearing are presented in detail. Further, it is shown that lubricants with couple stress and surface roughness, not only increases the load capacity and decreases the friction coefficient, but also generates a lower bearing temperature field. Thus, the lubricant with couple stress improves the performance of journal bearings. The characteristics of bearing are compared with numerical results.

Investigation the combined effects of wear and turbulent on the performance of hydrodynamic journal bearing operating with couple stress fluids

2019 ◽  
Vol 10 (6) ◽  
pp. 825-837
Author(s):  
Mushrek A. Mahdi ◽  
Ahmed Waleed Hussein
Keyword(s):  
Couple Stress ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Performance Characteristics ◽  
Turbulent Regime ◽  
Hydrodynamic Bearings ◽  
Content Type ◽  
Hydrodynamic Journal Bearing ◽  
Local Reynolds Number ◽  
Couple Stress Fluids

Purpose The purpose of this paper is to investigate the combined effect of wear and turbulence on the performance of a hydrodynamic journal bearing operating under Newtonian and couple stress fluids (CSF). Design/methodology/approach The analysis consists of a modified Reynolds equation of incompressible thin viscous films, and the film thickness model taking into account the wear effect. The governing equation was solved numerically using the finite difference approach. Findings The effect of both the wear parameter and the local Reynolds number on the performance characteristics of bearing has been presented and discussed. The obtained results observed that the characteristics of the intact and worn bearing in turbulent and laminar have been enhanced due to the non-Newtonian fluid (CSF) effect. Also, the results display that bearing worn and the turbulent regime cannot be neglected in calculating the performance characteristics of the bearing lubricated with Newtonian and non-Newtonian fluids. The results achieved from this study, specify that the bearing characteristics are significantly affected by these effects. Originality/value The paper investigates the behavior of hydrodynamic bearings considering different aspects simultaneously is interesting, and the application meets the current needs of improvement in modeling hydrodynamic bearings under different conditions.

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.

Influence of couple stress lubricant on the performance of textured two-lobe slot-entry hybrid journal bearing system

2016 ◽  
Vol 231 (3) ◽  
pp. 366-384 ◽  
Author(s):  
Chandra B Khatri ◽  
Satish C Sharma
Keyword(s):  
Couple Stress ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Critical Mass ◽  
Continuum Theory ◽  
Textured Surface ◽  
Stiffness Coefficients ◽  
Modified Reynolds Equation ◽  
Film Stiffness ◽  
Bearing System

This paper concerns with theoretical investigation to predict the combined influence of textured surface and couple stress lubricant behavior on the performance of circular/two-lobe slot-entry hybrid journal bearing. The flow of incompressible couple stress lubricant through the clearance of a textured journal bearing system is governed by the modified Reynolds equation. The modified Reynolds equation has been derived on the basis of Stokes micro-continuum theory and is solved using a finite element method technique for computing the bearing performance characteristics parameters. The static and dynamic characteristics of circular/two-lobe slot-entry hybrid journal bearing have been computed for textured and non-textured bearings with influence of couple stress lubricant. The present study indicates that the influence of couple stress lubricant behavior is significantly more on the values of fluid film stiffness coefficients [Formula: see text], critical mass of journal [Formula: see text], and stability threshold speed margin [Formula: see text] for textured surface than that of non-textured surface in case of a slot-entry hybrid journal bearing system.

Squeeze film characteristics of conical bearings operating with non-Newtonian lubricants – Rabinowitsch fluid model

2014 ◽  
Vol 66 (3) ◽  
pp. 373-378 ◽  
Author(s):  
Cheng-Hsing Hsu ◽  
Jaw-Ren Lin ◽  
Lian-Jong Mou ◽  
Chia-Chuan Kuo
Keyword(s):  
Reynolds Equation ◽  
Theoretical Study ◽  
Fluid Model ◽  
Load Capacity ◽  
Squeeze Film ◽  
Content Type ◽  
Closed Form Solutions ◽  
First Order ◽  
Small Perturbation Method ◽  
Film Characteristics

Purpose – The purpose of this paper is to present a theoretical study of non-Newtonian effects in conical squeeze-film plates that is based on the Rabinowitsch fluid model. Design/methodology/approach – A non-linear, modified Reynolds equation accounting for the non-Newtonian properties following the cubic stress law equation is derived. Through a small perturbation method, first-order closed-form solutions are obtained. Findings – It is found that the non-Newtonian properties of dilatant fluids increase the load capacity and lengthen the response time as compared to the case using a Newtonian lubricant; however, the non-Newtonian behaviors of pseudoplastic lubricants result in reverse influences. Originality/value – Numerical tables for squeeze-film loads of conical plates are also provided for engineering applications.

Combined effects of turbulence and elastic deformation on the performance of a journal bearing lubricated with a couple stress fluid

2018 ◽  
Vol 232 (12) ◽  
pp. 1597-1603 ◽  
Author(s):  
Boualem Chetti
Keyword(s):  
Elastic Deformation ◽  
Couple Stress ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Numerical Study ◽  
Performance Characteristics ◽  
Couple Stress Fluid ◽  
Turbulent Regime ◽  
Load Carrying ◽  
Modified Reynolds Equation

This paper presents a numerical study of the effect of turbulence and elastic deformation on the performance of a journal bearing operating with couple stress fluids, following Constantinescu’s turbulent lubrication theory. The modified Reynolds equation is derived taking into consideration the effect of turbulence and couple stresses. The modified Reynolds equation is solved using finite difference method. The results in terms of the load-carrying capacity, the attitude angle, friction coefficient and the side leakage are reported for various values of the couple stress parameter, the elastic coefficient, and Reynolds number. According to the obtained results, the couple stress fluid improves the performance characteristics of the rigid and deformed journal bearing in laminar and turbulent regimes. The results also show that bearing deformation and the turbulent regime cannot be neglected in calculating the performance characteristics of journal bearings lubricated with a Newtonian and a couple stress fluid.

The effect of turbulence on the performance of a two-lobe journal bearing lubricated with a couple stress fluid

2016 ◽  
Vol 68 (3) ◽  
pp. 336-340 ◽  
Author(s):  
Boualem Chetti
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Couple Stress ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Couple Stress Fluid ◽  
Turbulent Regime ◽  
Content Type ◽  
Couple Stress Fluids

Purpose This paper presents an analysis of the static characteristics of two-lobe journal bearings lubricated with couple stress fluids operating in a turbulent regime. The modified Reynolds equation for a couple stress fluids taking into consideration the effect of turbulence is solved using finite difference method. The load-carrying capacity, attitude angle, friction coefficient and side leakage are determined for various values of the couple stress parameter and Reynolds number. It is found that the couple stress fluids affect significantly on the performance of a two-lobe journal bearing in laminar and turbulent regime. Design/methodology/approach The modified Reynolds equation for a couple stress fluids taking into consideration the effect of turbulence is solved using finite difference method. Findings It is found that the couple stress fluids affect significantly on the performance of a two-lobe journal bearing in laminar and turbulent regime. Originality/value A couple stress fluid is used for lubrication of a two-lobe journal bearing in turbulent regime and laminar.

Performance characteristics of two-axial groove journal bearing for different groove angles

2018 ◽  
Vol 70 (2) ◽  
pp. 432-443
Author(s):  
K.R. Kadam ◽  
S.S. Banwait
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Conduction ◽  
Pressure Distribution ◽  
Heat Conduction Equation ◽  
Reynolds Equation ◽  
Energy Equation ◽  
Journal Bearing ◽  
Three Dimensional ◽  
Content Type

Purpose Different groove angles are used to study performance characteristics of two-axial groove journal bearing. In this study two grooves are located at ±90º to the load line. The various angles of grooves have been taken as 10° to 40° in the interval of 5°. Different equations such as Reynolds equation, three-dimensional energy equation and heat conduction equation have been solved using finite element method and finite difference method. Pressure distribution in fluid is found by using Reynolds equation. The three-dimensional energy equation is used for temperature distribution in the fluid film and bush. One-dimensional heat conduction equation is used for finding temperature in axial direction for journal. There is a very small effect of groove angle on film thickness, eccentricity ratio and pressure. There is a drastic change in attitude angle and side flow. Result shows that there is maximum power loss at large groove angle. So the smaller groove angle is recommended for two-axial groove journal bearing. Design/methodology/approach The finite element method is used for solving Reynolds equation for pressure distribution in fluid. The finite difference method is adopted for finding temperature distribution in bush, fluid and journal. Findings Pressure distribution in fluid is found out. Temperature distribution in bush, fluid and journal is found out. There is a very small effect of groove angle on film thickness, eccentricity ratio and pressure. Research limitations/implications The groove angle used is from 10 to 40 degree. The power loss is more when angle of groove increases, so smaller groove angle is recommended for this study. Practical implications The location of groove angle predicts the distribution of pressure and temperature in journal bearing. It will show the performance characteristics. ±90° angle we will prefer that will get before manufacturing of bearing. Social implications Due to this study, we will get predict how the pressure and temperature distribute in the journal. It will give the running condition of bearing as to at what speed and load we will get the maximum temperature and pressure in the bearing. Originality/value The finite element method is used for solving the Reynolds equation. Three-dimensional energy equation is solved using the finite difference method. Heat conduction equation is also solved for journal. The C language is used. The code is developed in C language. There are different equations which depend on each other. The temperature is dependent on pressure viscosity of fluid, etc. so C code is preferred.

A General Solution of Reynolds’ Equation for a Full Finite Journal Bearing

1967 ◽  
Vol 89 (2) ◽  
pp. 203-210 ◽  
Author(s):  
R. R. Donaldson
Keyword(s):  
Fourier Series ◽  
Series Solution ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Separation Of Variables ◽  
Hill Equation ◽  
Eigenvalues And Eigenvectors ◽  
General Series ◽  
Bearing Load

Reynolds’ equation for a full finite journal bearing lubricated by an incompressible fluid is solved by separation of variables to yield a general series solution. A resulting Hill equation is solved by Fourier series methods, and accurate eigenvalues and eigenvectors are calculated with a digital computer. The finite Sommerfeld problem is solved as an example, and precise values for the bearing load capacity are presented. Comparisons are made with the methods and numerical results of other authors.

Rayleigh Step Journal Bearing: Part 1—Compressible Fluid

1968 ◽  
Vol 90 (1) ◽  
pp. 271-280 ◽  
Author(s):  
B. J. Hamrock
Keyword(s):  
Compressible Fluid ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Pressure Profile ◽  
Clearance Ratio ◽  
Attitude Angle ◽  
Step Parameters ◽  
Bearing Part

A linearized PH solution to the Reynolds equation was obtained while neglecting side leakage. The analysis was divided into two parts—the step and ridge regions. The pressure profile across the step and ridge region of the various pads which are placed around the journal was obtained from the linearized PH Reynolds equation. Knowing the pressure, the load components and attitude angle were calculated. The resulting equations were found to be a function of the bearing parameters (the eccentricity and compressibility number) and the step parameters (ratio of the stepped clearance to the ridge clearance, ratio of the angle extended by the ridge to the angle extended by the pad, and number of pads placed around the journal). The maximum load capacity can be determined by numerically differentiating the load with respect to the step bearing parameters while finding where the slope is zero. A series of data was run while varying the bearing parameters. The attitude angle was calculated for the various cases which were run.

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