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.

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.

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.

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 effects of two-dimensional Reynolds roughness in hydrodynamic lubrication

1978 ◽  
Vol 364 (1716) ◽  
pp. 89-106 ◽  
Keyword(s):  
Surface Roughness ◽  
Numerical Computation ◽  
Autocorrelation Function ◽  
Reynolds Equation ◽  
Hydrodynamic Lubrication ◽  
The Other ◽  
Roughness Height ◽  
Two Dimensional ◽  
Roughness Effects ◽  
Dimensional Surface

The hydrodynamic lubrication of rough surfaces is analysed with the Reynolds equation, whose application requires the roughness spacing to be large, and the roughness height to be small, compared with the thick­ness of the fluid film. The general two-dimensional surface roughness is considered, and results applicable to any roughness structure are obtained. It is revealed analytically that two types of term contribute to roughness effects: one depends on the shape of the autocorrelation function and the other does not. The former contribution was neglected by previous workers. The numerical computation of an example shows that these two contributions are comparable in magnitude.

scholarly journals Hydrodynamic lubrication of rough surfaces

1982 ◽  
Vol 383 (1785) ◽  
pp. 439-446 ◽  
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Reynolds Equation ◽  
Hydrodynamic Lubrication ◽  
Rough Surfaces ◽  
Homogenization Method ◽  
Squeeze Film ◽  
Spatial Average

Using the two-space homogenization method we derive an averaged Reynolds equation that is correct to O (< H 6 > — < H 3 > 2 ), where H is the total film thickness and the angle brackets denote a spatial average. Applications of this mean Reynolds equation to a squeeze-film bearing with a sinusoidal or an isotropic surface roughness are discussed.

Surface Roughness Effects on Hydrodynamic Lubrication and Scuffing Failure Analysis of Axially Grooved Plunger of a Rotary Diesel Fuel Injection Pump

2004 ◽  
Author(s):  
M. Afzaal Malik ◽  
Badar Rashid ◽  
Shahab Khushnood ◽  
Raja Amer Azim
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Hydrodynamic Lubrication ◽  
Roughness Effects ◽  
Injection Pump ◽  
Fuel Injection Pump ◽  
Scuffing Failure ◽  
Diesel Fuel Injection

The wear between the plunger and plunger sleeve of rotary diesel fuel injection pump causes considerable decrease in injection pressure and the quantity of fuel to combustion chamber of an engine, which ultimately leads to failure of engine assembly. This research investigates the cause of failure particularly focusing on surface roughness effects to hydrodynamic lubrication and scuffing failure due to abrasive contaminant. The surface roughness of plunger and plunger sleeve were measured and incorporated in Reynolds equation to analyze roughness effects on hydrodynamic lubrication. The critical particle size of the dust normally present in the diesel fuel is evaluated to determine which test dust sample could cause systems to fail. Based on this information, scuffing failure of pumps due to an abrasive contaminant partially penetrated in the plunger sleeve is analyzed. The abrasive contaminant is modeled as a spherical shaped rigid particle. Excessive temperature rise between the particle-plunger interface is used as an indication of whether scuffing would take place. Experiments were conducted to determine parameters such as particle size of dust samples, surface roughness of plunger and plunger sleeve, specific heat of diesel fuel, diesel fuel density, quantity of fuel flow and radial clearance. These experimentally determined parameters are then used as input in our computer program to lend more confidence to our predicted results.

Normal Impact Model of Rough Surfaces

1992 ◽  
Vol 114 (3) ◽  
pp. 439-447 ◽  
Author(s):  
Wen-Ruey Chang ◽  
Frederick F. Ling
Keyword(s):  
Surface Roughness ◽  
Kinetic Energy ◽  
Surface Topography ◽  
Impact Velocity ◽  
Material Properties ◽  
Rough Surfaces ◽  
Impact Model ◽  
Normal Impact ◽  
Roughness Effects ◽  
Elastic Plastic

An elastic-plastic impact model for spheres is introduced as the basis to study the normal impact of rough surfaces. Statistics is applied to arrive at the ensemble behavior of many unit events alluded above, allowing the investigation of surface roughness effects. Dissipation of kinetic energy increases such as surface roughness, material compliance, and impact velocity is increased. The rebound velocity is shown to be dependent on surface topography and material properties, in addition to impact velocity.

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