Effect of Cavitation on Tribological Performances for Textured Surfaces

2012 ◽  
Vol 472-475 ◽  
pp. 391-394 ◽  
Author(s):  
Fan Ming Meng ◽  
Ling Zhang
Keyword(s):  
Fourier Transform ◽  
Friction Coefficient ◽  
Fast Fourier Transform ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Load Carrying Capacity ◽  
Textured Surfaces ◽  
Force Load ◽  
Cavitation Effect ◽  
Load Carrying

The influence of cavitation in a lubricant between textured surfaces on tribological performances of the surfaces was investigated based on an extended Reynolds equation and other associated equations. The tribological performances of the surfaces holding dimples with divergent-convergent shape were analyzed with the cavitation effect consideration at different dimple numbers. In doing so, the elastic deformation of the surface is evaluated using continuous convolution fast Fourier transform (CC-FFT). Some mechanisms are revealed about the cavitation effect on the friction coefficient, friction force, load-carrying capacity and cavitated area of the textured surfaces.

Steady-state performance of a circular journal bearing lubricated with a non-Newtonian fluid considering the elastic deformation of the liner

2019 ◽  
Vol 233 (9) ◽  
pp. 1389-1396
Author(s):  
Boualem Chetti ◽  
Hamid Zouggar
Keyword(s):  
Friction Coefficient ◽  
Elastic Deformation ◽  
Power Law ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Carrying Capacity ◽  
Static Characteristics ◽  
Load Carrying ◽  
Power Law Index

In this work, a numerical study of the effect of elastic deformation on the static characteristics of a circular journal bearing operating with non-Newtonian fluids obeying to the power law model is presented. The modified Reynolds equation has been derived taking into consideration the effect of non-Newtonian behavior of the fluids. To obtain the pressure distribution, the Reynolds equation has been solved using finite difference technique with appropriate iterative technique incorporating Reynolds boundary conditions. The static performance characteristics for finite-width journal bearing in terms of the load-carrying capacity, the attitude angle, friction coefficient, and the side leakage have been studied for various values of the non-Newtonian power law index n and the elastic coefficient. The results show that the increase of the power law index produces a higher load-carrying capacity, a higher side leakage, a lower attitude angle, and a lower friction coefficient. From this study, it can be concluded that the elastic deformation has an important influence on the static characteristics of the journal bearing lubricated with a non-Newtonian fluid, and this influence is more significant for the journal bearing operating at larger values of the eccentricity ratio.

scholarly journals Comparative study of spherical dimple and bump effects on the tribological performances of journal bearing

2018 ◽  
Vol 233 (1) ◽  
pp. 139-157 ◽  
Author(s):  
Chao Gui ◽  
Fanming Meng
Keyword(s):  
Friction Force ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Hydrodynamic Pressure ◽  
Load Carrying Capacity ◽  
Transform Method ◽  
Cavitation Effect ◽  
Fast Fourier Transform Method ◽  
Load Carrying

In the present study, tribological performances of journal bearings with the representative spherical dimples and bumps are compared numerically. In doing so, the hydrodynamic pressure of the lubricant is solved by the Reynolds equation considering the lubricant cavitation effect. Meanwhile, the elastic deformation is calculated by the continuous convolution fast Fourier transform method. The enhanced load-carrying capacity and the reduced friction force occur only when the dimples are located at pressure rising part of the bearing. The bumps located at the pressure falling part can enhance the load-carrying capacity but increase the friction force. The above dimple and bump effects change at the varied feature sizes and intervals.

Effects of Texture Density on Tribological Performance of Laser Peen Textured Surface

2013 ◽  
Vol 404 ◽  
pp. 106-111
Author(s):  
Kang Mei Li ◽  
Zhen Qiang Yao ◽  
Yong Xiang Hu
Keyword(s):  
Friction Coefficient ◽  
Carrying Capacity ◽  
Failure Time ◽  
Normal Load ◽  
Effective Means ◽  
Textured Surface ◽  
Load Carrying Capacity ◽  
Textured Surfaces ◽  
Texture Density ◽  
Load Carrying

Surface texturing has been recognized as an effective means to improve the tribological performances of sliding surfaces. Different densities of micro dimples were fabricated on Oxygen-Free High Conductivity (OFHC) copper by laser peen texturing (LPT). The tribological characteristics of the samples were tested by surface-to-surface sliding contact experiments under constant sliding velocity and linearly increased normal load. The effects of texture density on the friction coefficient, failure time and load carrying capacity were investigated. It was found that in comparison with smooth surfaces, textured surfaces help to reduce the friction coefficient, prolong the failure time and improve the load carrying capacity. Results also suggested that there might exit an optimum texture density with which the surface exhibits better tribological behavior than those with higher and lower texture densities.

Study on Tribological Performances for Textured Bearing of ICE

2013 ◽  
Vol 690-693 ◽  
pp. 1999-2002
Author(s):  
Fan Ming Meng ◽  
Tao Yang ◽  
Tao Long
Keyword(s):  
Friction Coefficient ◽  
Internal Combustion Engine ◽  
Carrying Capacity ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Load Carrying Capacity ◽  
Oil Film ◽  
Load Carrying ◽  
Inner Surface ◽  
Coupling Algorithm

The influence of dimples on the inner surface of big end bearing in internal combustion engine (ICE) on tribological performances of the bearing was investigated based on Navier-Strokes equation and other associated equations. In doing so, the CFD modulus in the software ANSYS12 version is used to analyze the dimple effect on the tribological performances of the bearing using two-way fluid-solid coupling algorithm. Some mechanisms are revealed about the dimple effect on the load-carrying capacity and friction coefficient of oil film, and the deformation and stress for the textured big end bearing.

The Validity of the Reynolds Equation in Modeling Hydrostatic Effects in Gas Lubricated Textured Parallel Surfaces

2005 ◽  
Vol 128 (2) ◽  
pp. 345-350 ◽  
Author(s):  
Y. Feldman ◽  
Y. Kligerman ◽  
I. Etsion ◽  
S. Haber
Keyword(s):  
Carrying Capacity ◽  
Reynolds Equation ◽  
Stokes Equations ◽  
Surface Texturing ◽  
Laser Surface Texturing ◽  
Physical Parameters ◽  
Load Carrying Capacity ◽  
Wide Range ◽  
Load Carrying ◽  
Parallel Surfaces

Microdimples generated by laser surface texturing (LST) can be used to enhance performance in hydrostatic gas-lubricated tribological components with parallel surfaces. The pressure distribution and load carrying capacity for a single three-dimensional dimple, representing the LST, were obtained via two different methods of analysis: a numerical solution of the exact full Navier-Stokes equations, and an approximate solution of the much simpler Reynolds equation. Comparison between the two solution methods illustrates that, despite potential large differences in local pressures, the differences in load carrying capacity, for realistic geometrical and physical parameters, are small. Even at large clearances of 5% of the dimple diameter and pressure ratios of 2.5 the error in the load carrying capacity is only about 15%. Thus, for a wide range of practical clearances and pressures, the simpler, approximate Reynolds equation can safely be applied to yield reasonable predictions for the load carrying capacity of dimpled surfaces.

Static characteristics of misaligned multiple axial groove water-lubricated bearing in the turbulent regime

2016 ◽  
Vol 231 (3) ◽  
pp. 385-398 ◽  
Author(s):  
Ravindra Mallya ◽  
Satish B Shenoy ◽  
Raghuvir Pai
Keyword(s):  
Reynolds Number ◽  
Friction Coefficient ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Load Capacity ◽  
Turbulent Regime ◽  
Load Carrying Capacity ◽  
Static Characteristics ◽  
Load Carrying ◽  
Turbulence Effects

The static characteristics of misaligned three-axial water-lubricated journal bearing in the turbulent regime are analyzed for groove angles 36° and 18°. Ng and Pan’s turbulence model is applied to study the turbulence effects in the journal bearing. The static parameters such as load-carrying capacity, friction coefficient, and side leakage are found for different degree of misalignment (DM). The change in flow regime of the lubricant from laminar to turbulent and the increase in misalignment, improved the load capacity of the bearing. For lightly loaded bearings, the friction coefficient of the bearing increased with the increase in Reynolds number.

Partially Textured Slider and Journal Bearing Analysis

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
T. V. V. L. N. Rao ◽  
A. M. A. Rani ◽  
T. Nagarajan ◽  
F. M. Hashim
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Load Capacity ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Bearing Analysis

The present study examines the influence of partial texturing of bearing surfaces on improvement in load capacity and reduction in friction coefficient for slider and journal bearing. The geometry of partially textured slider and journal bearing considered in this work composed of a number of successive regions of groove and land configurations. The nondimensional pressure expressions for the partially textured slider and journal bearing are derived taking into consideration of texture geometry and extent of partial texture. Partial texturing has a potential to generate load carrying capacity and reduce coefficient of friction, even for nominally parallel bearing surfaces.

Hydrodynamic Lubrication of Finite Slider Bearings: Effect of One Dimensional Film Shape, and Their Computer Aided Optimum Designs

1983 ◽  
Vol 105 (1) ◽  
pp. 48-63 ◽  
Author(s):  
C. Bagci ◽  
A. P. Singh
Keyword(s):  
Numerical Solution ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Hydrodynamic Lubrication ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Design Data ◽  
Slider Bearings ◽  
Load Carrying ◽  
Computer Aided

The effect of the film shape on the load carrying capacity of a hydrodynamically lubricated bearing has not been considered an important factor in the past. Flat-faced tapered bearing and the Raileigh’s step bearing of constant film thickness have been the primary forms of film shapes for slider bearing studies and design data developments. This article, by the computer aided numerical solution of the Reynolds equation for two dimensional incompressible lubricant flow, investigates hydrodynamically lubricated slider bearings having different film shapes and studies the effect of the film shape on the performance characteristics of finite bearings; and it shows that optimized bearing with film shapes having descending slope toward the trailing edge of the bearing has considerably higher load carrying capacity than the optimized flat-faced tapered bearing of the same properties. For example the truncated cycloidal film shape yields 26.3 percent higher load carrying capacity for Lz/Lx = 1 size ratio, and 44 percent higher for Lz/Lx = 1/2. The article then presents charts for the optimum designs of finite slider bearings having tapered, exponential, catenoidal, polynomial, and truncated-cycloidal film shapes, and illustrates their use in numerical bearing design examples. These charts also furnish information on flow rate, side leakage, temperature rise, coefficient of friction, and friction power loss in optimum bearings. Appended to the article are analytical solutions for infinitely wide bearings with optimum bearing characteristics. The computer aided numerical solution of the Reynolds equation in most general form is presented by which finite or infinitely wide hydrodynamically or hydrostatically lubricated bearings, externally pressurized or not, can be studied. A digital computer program is made available.

Theoretical Analysis of Externally Pressurized Air Journal Bearing

1970 ◽  
Vol 12 (2) ◽  
pp. 123-129 ◽  
Author(s):  
B. C. Majumdar
Keyword(s):  
Experimental Data ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Dimensional Parameters ◽  
Bearing Design

A theoretical investigation is made to predict the performance of an externally pressurized air journal bearing having several pressure sources. The pressure distribution, which leads to the determination of load-carrying capacity and flow requirement, is obtained by solving Reynolds equation numerically. The load and flow, expressed in non-dimensional parameters, are presented for different bearing design parameters (dimensionless). The results predicted by this method are compared with others' experimental data.

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