The Hydrodynamic Lubrication of Rough Bearing Surfaces of Finite Width

1971 ◽  
Vol 93 (3) ◽  
pp. 324-329 ◽  
Author(s):  
H. Christensen ◽  
K. Tonder
Keyword(s):  
Surface Roughness ◽  
Theoretical Analysis ◽  
Hydrodynamic Lubrication ◽  
Stochastic Theory ◽  
Finite Width ◽  
Operational Factors ◽  
Effect Of Surface

The paper describes a theoretical analysis of the effects of surface roughness in a finite width bearing. The analysis is based upon a stochastic theory of hydrodynamic lubrication developed previously. It is shown how the effect of surface roughness on the bearing characteristics is closely tied up with features of nominal geometry as well as with operational factors.

Surface Roughness Effects in Infinitely Long Porous Journal Bearings

1999 ◽  
Vol 121 (1) ◽  
pp. 139-147 ◽  
Author(s):  
K. Gururajan ◽  
J. Prakash
Keyword(s):  
Surface Roughness ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Rough Surfaces ◽  
Stochastic Theory ◽  
Journal Bearings ◽  
Roughness Effects ◽  
Effect Of Surface

Christensen’s stochastic theory of hydrodynamic lubrication of rough surfaces is used to study the effect of surface roughness in an infinitely long porous journal bearing operating under steady conditions. It is shown that the surface roughness considerably influences the bearing performance; the direction of the influence depends on the roughness type.

Lubrication of a Porous Bearing With Surface Corrugations

1982 ◽  
Vol 104 (1) ◽  
pp. 127-134 ◽  
Author(s):  
J. Prakash ◽  
K. Tiwari
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Lubrication ◽  
Rough Surfaces ◽  
Stochastic Theory ◽  
Circular Plates ◽  
Operating Characteristics ◽  
Roughness Effects ◽  
Porous Bearing

The paper considers the surface roughness effects in hydrodynamic porous bearings. On the basis of stochastic theory of hydrodynamic lubrication of rough surfaces developed by Christensen, different forms of Reynolds type equations, as applicable to a general porous bearings are derived for various types of surface roughness pattern. To illustrate the functional effects of surface roughness on the operating characteristics of a porous bearing, the case of nonrotating circular plates in normal approach is analyzed. It is shown that surface roughness may considerably influence the operating characteristics of porous bearings. The direction of the influence, however, depends upon the type of roughness assumed.

Effect of Surface Roughness on Hydrodynamic Lubrication of Slider Bearings

2001 ◽  
Vol 44 (2) ◽  
pp. 291-297 ◽  
Author(s):  
P. I. Andharia ◽  
J. L. Gupta ◽  
G. M. Deheri
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Lubrication ◽  
Slider Bearings ◽  
Effect Of Surface

Roughness Effects in Porous Circular Squeeze-Plates With Arbitrary Wall Thickness

1983 ◽  
Vol 105 (1) ◽  
pp. 90-95 ◽  
Author(s):  
J. Prakash ◽  
K. Tiwari
Keyword(s):  
Wall Thickness ◽  
Hydrodynamic Lubrication ◽  
Stochastic Theory ◽  
Squeeze Film ◽  
Approximate Analysis ◽  
Tabular Form ◽  
Circular Plates ◽  
Roughness Effects ◽  
Influencing Parameters ◽  
Effect Of Surface

The stochastic theory of hydrodynamic lubrication of rough surfaces is used to study the effect of surface roughness on the response of a squeeze film between two circular plates when one plate has a porous facing. An exact solution is given for the film pressure and pressure in the bearing matrix, valid for arbitrary wall thickness. The results are presented in tabular form and a comparison is made with an earlier approximate analysis to determine the range of influencing parameters for which the approximate solution is acceptable.

The comprehensive effect of surface texture and roughness under hydrodynamic and mixed lubrication conditions

2017 ◽  
Vol 231 (10) ◽  
pp. 1307-1319 ◽  
Author(s):  
Chenbo Ma ◽  
Yanjun Duan ◽  
Bo Yu ◽  
Jianjun Sun ◽  
Qiaoan Tu
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Hydrodynamic Lubrication ◽  
Diameter Ratio ◽  
Mixed Lubrication ◽  
Textured Surface ◽  
Texture Parameters ◽  
Lubrication Condition ◽  
Lubrication Conditions ◽  
Effect Of Surface

A theoretical study is carried out to investigate the comprehensive effect of the machined roughness and fabricated textures, by solving the average Reynolds equation coupled with a mass-conservative cavitation algorithm and taking into account asperity contact. We analyzed the influence of surface roughness, which is represented by the combined root-mean-square roughness σ and surface pattern parameter γ on the optimum texture parameters including the dimple depth-over-diameter ratio and area density under hydrodynamic and mixed lubrication conditions. The results show that the effect of surface roughness on load-carrying capacity can be ignored under hydrodynamic lubrication condition. Furthermore, the optimum texture parameters under hydrodynamic lubrication condition and the optimum dimple depth-over-diameter ratio under mixed lubrication condition are determined at minimized friction coefficient, which can be taken as the same for smooth-textured surface and rough-textured surface. The corresponding minimum friction coefficient increases with increasing σ and γ, and decreasing dimple area density under mixed lubrication condition.

The Effect of Surface Roughness on the Average Film Thickness Between Lubricated Rollers

1976 ◽  
Vol 98 (1) ◽  
pp. 117-124 ◽  
Author(s):  
L. S. H. Chow ◽  
H. S. Cheng
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Stochastic Models ◽  
Hydrodynamic Lubrication ◽  
Elastohydrodynamic Lubrication ◽  
Type Equation ◽  
Slider Bearing ◽  
Reduced Pressure ◽  
Average Film Thickness ◽  
Effect Of Surface

The Christensen theory of stochastic models [7] for hydrodynamic lubrication of rough surfaces is extended to elastohydrodynamic lubrication between two rollers. The Grubin-type equation including asperity effects in the inlet region is derived. Solutions for the reduced pressure at the entrance as a function of the ratio of the average nominal film thickness to the r.m.s. surface roughness (in terms of standard deviation σ), have been obtained numerically. Results were obtained for purely transverse as well as purely longitudinal surface roughness for cases with or without slip. The reduced pressure is shown to decrease slightly by considering longitudinal surface roughness. The transverse surface roughness, on the other hand, has a slight beneficial effect on the average film thickess at the inlet. The same approach was used to study the effect of surface roughness on lubrication between rigid rollers and lubrication of an infinitely-wide slider bearing. Results of these two cases show that the effects of surface roughness are similar to those found in elastohydrodynamic contacts.

Stochastic Models for Hydrodynamic Lubrication of Rough Surfaces

1969 ◽  
Vol 184 (1) ◽  
pp. 1013-1026 ◽  
Author(s):  
H. Christensen
Keyword(s):  
Surface Roughness ◽  
Stochastic Models ◽  
Reynolds Equation ◽  
Hydrodynamic Lubrication ◽  
Stochastic Theory ◽  
Type Equation ◽  
Mathematical Form ◽  
Slider Bearing ◽  
Operating Characteristics ◽  
Different Types

This paper deals with hydrodynamic aspects of rough bearing surfaces. On the basis of stochastic theory two different forms of Reynolds-type equation corresponding to two different types of surface roughnesses are developed. It is shown that the mathematical form of these equations is similar but not identical to the form of the Reynolds equation governing the behaviour of smooth, deterministic bearing surfaces. To illustrate the functional effects of surface roughness the influence on the operating characteristics of a plane pad, no side leakage slider bearing is analysed. It is shown that surface roughness may considerably influence the operating characteristics of bearings and that the direction of the influence depends upon the type of roughness assumed. The effects are not, however, critically dependent upon the detailed form of the distribution function of the roughness heights.

On the Lubrication of Rough Rollers

1984 ◽  
Vol 106 (2) ◽  
pp. 211-217 ◽  
Author(s):  
J. Prakash
Keyword(s):  
Surface Roughness ◽  
Stochastic Model ◽  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Roughness Parameter ◽  
Dimensionless Parameters ◽  
Surface Roughness Parameter ◽  
Cylinder Radius ◽  
Minimum Film Thickness ◽  
Effect Of Surface

Christensen’s stochastic model of hydrodynamic lubrication as extended to two sided roughness is used to study the effect of surface roughness in the analysis of lightly loaded rollers in combined rolling, sliding and normal motion. A detailed study of the above system in terms of dimensionless parameters, Q (involving the normal and entraining velocity, the minimum film thickness and the equivalent cylinder radius); the slide roll ratio and the surface roughness parameter is made for purely longitudinal and purely transverse surface roughness.

Micropolarity—Roughness Interaction in Hydrodynamic Lubrication

1980 ◽  
Vol 102 (3) ◽  
pp. 368-372 ◽  
Author(s):  
J. Prakash ◽  
K. To̸nder ◽  
H. Christensen
Keyword(s):  
Surface Roughness ◽  
Theoretical Analysis ◽  
Micropolar Fluid ◽  
Hydrodynamic Lubrication ◽  
Type Equation ◽  
Pressure Level ◽  
Surface Forces ◽  
Direction Transverse ◽  
One Dimensional ◽  
Fluid Theory

The paper describes a theoretical analysis of micropolarity-roughness interaction. A modified Reynolds’ type equation for a rough surface based on micropolar fluid theory is developed and is applied to the case of a fixed inclined slider, having a one-dimensional roughness pattern in the direction transverse to sliding. The analysis shows that the inclusion of surface roughness in the theory causes an increase in the pressure level, over and above the micropolar level. However, these additional increases are of a smaller order and are not likely to mask the increases caused by additives and surface forces (characterized by micropolarity) as is conjectured by some earlier workers.

Sign in / Sign up

Export Citation Format

Share Document