Lubricant Film Rupture

Analyses of liquid film journal bearings rarely consider the reformation of the lubricant film. This reformation normally takes place in the vicinity of a supply groove and is influenced by, amongst other parameters, the lubricant supply pressure. In a previous paper the authors have described in detail the implementation of an algorithm to locate automatically and efficiently the locus of film rupture and reformation boundaries using a digital computer. In the present paper results are presented for a wide range of important variables. In particular, the prediction of lubricant supply rate is studied carefully and compared with data presented in a widely used design aid which does not account in detail for the influence of film reformation.

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Research on Discontinuity of Lubricant Film in Journal Bearing : 1st Report, Bearing Characteristics and Oil Film Rupture

Transactions of the Japan Society of Mechanical Engineers ◽

10.1299/kikai1938.33.658 ◽

1967 ◽

Vol 33 (248) ◽

pp. 658-666 ◽

Cited By ~ 2

Author(s):

Haruo MORI ◽

Seiji MIYATA ◽

Yasuo ABE ◽

Yoshio FUJITA

Keyword(s):

Journal Bearing ◽

Lubricant Film ◽

Film Rupture ◽

Oil Film

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Axial Oil Film Rupture in High Speed Bearings Due to the Effect of the Centrifugal Force

Journal of Tribology ◽

10.1115/1.2831264 ◽

1995 ◽

Vol 117 (3) ◽

pp. 394-398 ◽

Cited By ~ 8

Author(s):

Carlos E. Koeneke ◽

Masato Tanaka ◽

Hisayuki Motoi

Keyword(s):

Centrifugal Force ◽

High Speed ◽

Axial Direction ◽

Lubricant Film ◽

Navier Stokes ◽

Film Rupture ◽

Navier Stokes Equation ◽

High Rotational Speed ◽

Lubricating Film ◽

Very High

The two-dimensional steady-state Navier-Stokes equation and the continuity equation are applied to the lubricating film assumed to be concentric in journal bearings operating at very high speeds. The equations are numerically solved for the pressure variation in the axial direction and also across the film thickness with the centrifugal force being considered to act on the lubricant film due to high rotational speed of the journal. Linked with a new cavitation model proposed, the lubricant film is theoretically found to rupture near the journal surface toward the bearing end. This axial film rupture (AFR) is shown to reduce the driving torque of the inner film of floating bush bearings at very high shaft speeds, and some phenomena observed in the operation of floating bush bearings can be explained with this model.

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Research on Discontinuity of Lubricant Film in Journal Bearings : 1st Report, Bearing Characteristics and Lubricant Film Rupture

Bulletin of JSME ◽

10.1299/jsme1958.10.1039 ◽

1967 ◽

Vol 10 (42) ◽

pp. 1039-1047 ◽

Cited By ~ 2

Author(s):

Haruo MORI ◽

Seiji MIYATA ◽

Yasuo ABE ◽

Yoshio FUJITA

Keyword(s):

Journal Bearings ◽

Lubricant Film ◽

Film Rupture

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Assessment of friction from compression ring conjunction of a high-performance internal combustion engine: A combined numerical and experimental study

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406215588480 ◽

2015 ◽

Vol 230 (12) ◽

pp. 2073-2085 ◽

Cited By ~ 20

Author(s):

M Gore ◽

R Rahmani ◽

H Rahnejat ◽

PD King

Keyword(s):

High Performance ◽

Combustion Engine ◽

Viscous Friction ◽

Cylinder Liner ◽

Lubricant Film ◽

Film Rupture ◽

Compression Ring ◽

Piston Cylinder ◽

Direct Measurements ◽

Good Agreement

The paper presents direct measurement of in-cylinder friction from a single cylinder motocross race engine under motored conditions and compares the same with a new analytical predictive method. These conditions are encountered in piston–cylinder system with the application of cylinder deactivation (CDA) technology, which is a growing trend. The analytical method takes into account the various regions within instantaneous contact of compression ring–cylinder liner, including lubricant film rupture, cavitation zone and the subsequent lubricant film reformation. The analysis also includes the effect of boundary friction and lubricant rheology. The predictions and direct measurements of cyclic friction show good agreement and indicate dominance of viscous friction under the investigated engine running conditions. In particular, it is shown that the compression ring contribution to in-cycle friction is most pronounced in the region of high cylinder pressures because of combined Poiseuille friction and some boundary solid interactions. The combined experimental-analytical approach has not hitherto been reported in literature.

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On the Appearance of Lubricant Film Rupture in Cylindrical Journal Bearings

Tribology Transactions ◽

10.1080/05698190490439120 ◽

2004 ◽

Vol 47 (2) ◽

pp. 233-238 ◽

Cited By ~ 1

Author(s):

Valery R. Nosov ◽

J. Gomez-Mancilla

Keyword(s):

Journal Bearings ◽

Lubricant Film ◽

Film Rupture

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Hydrodynamic Lubricant Film Separation During Codirectional and Counter-Directional Rotations of Disengaged Wet Clutch Packs

Journal of Fluids Engineering ◽

10.1115/1.4044443 ◽

2019 ◽

Vol 142 (1) ◽

Author(s):

N. J. Morris ◽

R. Patel ◽

H. Rahnejat

Keyword(s):

Boundary Condition ◽

Reverse Flow ◽

Lubricant Film ◽

Operating Conditions ◽

Power Losses ◽

Film Rupture ◽

Significant Power ◽

Flow Boundary ◽

Wet Clutch ◽

Film Separation

Abstract The parasitic drag losses incurred by wet clutches, used in transmission systems, can significantly affect vehicular powertrain efficiency. This paper presents a novel implicit solution for hydrodynamic parasitic drag losses of disengaged clutches. These are generated by conjunctional friction, taking into account lubricant film separation during codirectional and counter-directional disk pair rotations. Lubricant film rupture is considered through application of incipient reverse flow boundary condition, which is representative of lubricant film separation. The results point to the operating conditions at which significant power losses occur. In particular, the time efficient model is able to represent the small losses incurred during codirectional rotation of disk pairs.

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