Surface roughness effects on thermo-hydrodynamic lubrication of journal bearings lubricated with bubbly oil

10.1002/ls.5 ◽  
2005 ◽  
Vol 18 (1) ◽  
pp. 49-61 ◽  
Author(s):  
A. M. A. El-Butch ◽  
N. El-Tayeb
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Roughness Effects

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.

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.

Application of the Hopf bifurcation theory to limit cycle prediction of short journal bearings with isotropic roughness effects

2007 ◽  
Vol 221 (8) ◽  
pp. 869-879 ◽  
Author(s):  
J-R Lin
Keyword(s):  
Surface Roughness ◽  
Hopf Bifurcation ◽  
Limit Cycles ◽  
Critical Region ◽  
System Parameter ◽  
Journal Bearings ◽  
Roughness Effects ◽  
Critical Limit ◽  
Bifurcation Behaviour ◽  
Bearing System

On the basis of the Christensen stochastic theory, the effects of isotropic surface roughness upon the bifurcation behaviour of a short journal-bearing system are investigated. By applying the Hopf bifurcation theorem to the non-linear equations of motion of rough journal bearings, the steady-state performance, the linear characteristics, and the weakly non-linear bifurcationphenomenaarepresented. For the short bearing with length-to-diameter ratio l = 0. 5, the onset of oil-whirl rough bearing system can manifest a bifurcation behaviour exhibiting subcritical limit cycles or super-critical limit cycles for running speeds near the bifurcation point. For a particular system parameter, the effects of isotropic surface roughness are found to enlarge the size of sub-critical limit cycles and super-critical limit cycles when the Hopf bifurcation occurs. On the whole, the roughness effects of isotropic surface patterns upon the Hopf bifurcation phenomena of the short-bearing system are more pronounced for a smaller system parameter ( p = 0. 4 in the sub-critical region and Sp = 0. 05 in the super-critical region) and a higher roughness parameter (Λ = 0. 4).

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 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.

Surface Roughness Effects in Journal Bearings with Non-Newtonian Lubricants

1996 ◽  
Vol 39 (4) ◽  
pp. 819-826 ◽  
Author(s):  
Wang-Long Li ◽  
Cheng-I Weng ◽  
Jang-I Lue
Keyword(s):  
Surface Roughness ◽  
Journal Bearings ◽  
Roughness Effects
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