Developments in Fluid Film Bearing Technology

In high speed, high load fluid-film bearings, the laminar-turbulent flow transition can lead to a considerable reduction of the maximum bearing temperatures, due to a homogenization of the fluid-film temperature in radial direction. Since this phenomenon only occurs significantly in large bearings or at very high sliding speeds, means to achieve the effect at lower speeds have been investigated in the past. This paper shows an experimental investigation of this effect and how it can be used for smaller bearings by optimized eddy grooves, machined into the bearing surface. The investigations were carried out on a Miba journal bearing test rig with Ø120 mm shaft diameter at speeds between 50 m/s–110 m/s and at specific bearing loads up to 4.0 MPa. To investigate the potential of this technology, additional temperature probes were installed at the crucial position directly in the sliding surface of an up-to-date tilting pad journal bearing. The results show that the achieved surface temperature reduction with the optimized eddy grooves is significant and represents a considerable enhancement of bearing load capacity. This increase in performance opens new options for the design of bearings and related turbomachinery applications.

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First Paper: Effect of Under-Lip Temperature on the Lubrication of Rotary Shaft Garter Spring Seals

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1966_181_020_02 ◽

1966 ◽

Vol 181 (1) ◽

pp. 185-190 ◽

Cited By ~ 5

Author(s):

D. J. Lines ◽

J. M. Lawrie ◽

J. P. O'Donoghue

Keyword(s):

Coefficient Of Friction ◽

Operating Temperature ◽

Lubrication Theory ◽

Fluid Film ◽

Hydrodynamic Parameter ◽

Accurate Knowledge ◽

The Coefficient Of Friction ◽

Surface Thermocouple ◽

Sealing Mechanism ◽

Film Lubrication

Although rotary shaft garter spring seals are widely used throughout industry, very little is known about the sealing mechanism of the lip-shaft interface. It is now generally accepted that some sort of fluid film separates the lip and the shaft. Previous workers have also postulated a relationship between the coefficient of friction and a non-dimensional hydrodynamic parameter, as in standard lubrication theory. This present paper clarifies this relationship, and shows that seals can also operate over the mixed friction, as well as the full film lubrication region. The results were obtained by accurate knowledge of the operating temperature under the sealing lip. Two types of surface thermocouple were developed to do this and these are described in full.

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Effect of Rolling Velocity and Maximum Hertzian Pressure on Fluid Film in Steady State EHL Line Contact with Rough Surface and Linear Piezoviscosity

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.592-594.1371 ◽

2014 ◽

Vol 592-594 ◽

pp. 1371-1375

Author(s):

Nitesh Talekar ◽

Punit Kumar

Keyword(s):

Surface Roughness ◽

Steady State ◽

Film Thickness ◽

Rough Surface ◽

Computer Code ◽

Fluid Film ◽

Line Contact ◽

Rolling Velocity ◽

Load Carrying ◽

Lubricated Contact

Consideration of surface roughness in steady state EHL line contact is the first step towards understanding the lubrication of rough surface problem. Current paper investigates the use of sinusoidal waviness in the contact; more precisely it gives performance of real fluid in EHL line contact. The effect of various parameters like rolling velocity (U) and maximum Hertzian pressure (ph) on surface roughness by using properties of linear and exponential piezo-viscosity is taken into consideration to evaluate behavior of pressure distribution of load carrying fluid film and film thickness. Full isothermal, Newtonian simulation of EHL problem gives described effects. Spiking or fluctuation of pressure and film thickness curves is expected to show presence of irregularities on the surface chosen and amount of fluctuation depends on certain parameters and intensity of irregularities present. Rolling side domain of-4.5 ≤ X ≤ 1.5 with grid size ∆X=0.01375 is selected. A computer code is developed to solve Reynolds equation, which governs the generation of pressure in the lubricated contact zone is discritized and solved along with load balance equation using Newton-Raphson technique.

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ALE formulation of Reynolds fluid film equation

ZAMM ‐ Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik ◽

10.1002/zamm.200800005 ◽

2008 ◽

Vol 88 (9) ◽

pp. 716-728 ◽

Cited By ~ 3

Author(s):

B. Schweizer

Keyword(s):

Fluid Film ◽

Ale Formulation

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Magnetohydrodynamic Squeeze Film Characteristics Between Parallel Circular Plates Containing a Single Central Air Bubble in the Inertial Flow Regime

Journal of Applied Mechanics ◽

10.1115/1.2791773 ◽

1999 ◽

Vol 66 (4) ◽

pp. 1021-1023 ◽

Cited By ~ 7

Author(s):

R. Usha ◽

P. Vimala

Keyword(s):

Magnetic Field ◽

Differential Equation ◽

Nonlinear Differential Equation ◽

Bubble Radius ◽

Fluid Film ◽

Squeeze Film ◽

Parallel Plates ◽

Circular Plates ◽

Air Bubble ◽

Approximate Analytical Solutions

In this paper, the magnetic effects on the Newtonian squeeze film between two circular parallel plates, containing a single central air bubble of cylindrical shape are theoretically investigated. A uniform magnetic field is applied perpendicular to the circular plates, which are in sinusoidal relative motion, and fluid film inertia effects are included in the analysis. Assuming an ideal gas under isothermal condition for an air bubble, a nonlinear differential equation for the bubble radius is obtained by approximating the momentum equation governing the magnetohydrodynamic squeeze film by the mean value averaged across the film thickness. Approximate analytical solutions for the air bubble radius, pressure distribution, and squeeze film force are determined by a perturbation method for small amplitude of sinusoidal motion and are compared with the numerical solution obtained by solving the nonlinear differential equation. The combined effects of air bubble, fluid film inertia, and magnetic field on the squeeze film force are analyzed.

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