The Characteristics of a Statically Loaded Journal Bearing with Superlaminar Flow

1980 ◽  
Vol 22 (2) ◽  
pp. 79-94 ◽  
Author(s):  
R. E. Hinton ◽  
J. B. Roberts
Keyword(s):  
Friction Factor ◽  
Journal Bearing ◽  
Load Capacity ◽  
Reynolds Numbers ◽  
Diameter Ratio ◽  
Experimental Results ◽  
Empirical Theory ◽  
Clearance Ratio ◽  
Friction Factors ◽  
Theoretical Predictions

Experimental results are presented, relating to the friction factor, load capacity and attitude angle, for a plain, cylindrical journal bearing with a central, circumferential inlet groove. The length to diameter ratio of the journal bearing was 1/3 and the clearance ratio was 0.011. By the use of various lubricants, including water, Reynolds numbers ranging from 40 to 50 000 were attained. Comparisons with various theoretical predictions are given. It is shown that a simple, empirical theory, which incorporates measured friction factors, gives better agreement with the experimental load capacity results than previous theories.

On the Load Capacity of the MHD Journal Bearing

1968 ◽  
Vol 90 (1) ◽  
pp. 139-144 ◽  
Author(s):  
S. J. Dudzinsky ◽  
F. J. Young ◽  
W. F. Hughes
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Journal Bearing ◽  
Hartmann Number ◽  
Load Capacity ◽  
External Source ◽  
Diameter Ratio ◽  
Experimental Results ◽  
Eccentricity Ratio ◽  
Applied Current

An analysis and experimental results are presented for a magnetohydrodynamic partial journal bearing using a liquid metal lubricant. An external magnetic field is applied axially along the journal, and current is permitted to flow between the journal and bearing. The analysis shows that increased load capacity can be achieved by supplying current from an external source. In addition, the analysis reveals the existence of an optimum Hartmann number at which the load capacity peaks for a given applied current. This optimum value is about 5 for a dimensionless current I¯ = −5 applied to a bearing with a width/diameter ratio of 1 and an eccentricity ratio of 0.6. Experimental results which demonstrate the increase in load capacity resulting from an externally applied current are presented graphically and compared with the theory.

An Experimental Investigation of Pressure Distributions in a Journal Bearing Operating in the Transition Regime

1986 ◽  
Vol 200 (4) ◽  
pp. 251-264 ◽  
Author(s):  
J B Roberts ◽  
P J Mason
Keyword(s):  
Reynolds Number ◽  
Friction Factor ◽  
Journal Bearing ◽  
Transition Regime ◽  
Pressure Measurements ◽  
Eccentricity Ratio ◽  
Clearance Ratio ◽  
Viscosity Parameter ◽  
Pressure Distributions ◽  
Friction Factors

Experimental results are presented, relating to friction factors and circumferential pressure distributions, for a plain cylindrical journal bearing with a central circumferential inlet groove. The length-diameter ratio of each journal bearing land was 0.25 and the clearance ratio was 0.0031. The friction factor results showed the existence of a distinct ‘transition regime’, characterized by a pronounced ‘hump’ in the friction factor-Reynolds number relationship. Pressure measurements recorded when operating in this transition regime revealed the inadequacy of many existing ‘turbulent’ theories for superlaminar lubrication. By using a short-bearing theory a good correlation of the pressure distribution results was obtained, in terms of a non-dimensional viscosity parameter, kz, which is dependent on both the eccentricity ratio and Reynolds number. The magnitude of kz in this regime was considerably higher than the corresponding value for laminar flow, and was similar to the magnitude predicted from a simple theory based on relating kz to the variation of measured friction factor with Reynolds number.

Experimental Determination of Friction Factors for Straight and Curved Microchannels

2010 ◽  
Vol 5 (3) ◽  
pp. 63-70
Author(s):  
Vladimir М. Aniskin ◽  
Kseniya V. Adamenko ◽  
Anatoliy A. Maslov
Keyword(s):  
Friction Factor ◽  
Software Package ◽  
Reference Value ◽  
Reynolds Numbers ◽  
Experimental Results ◽  
Friction Factors ◽  
Inner Diameter ◽  
Curved Section ◽  
Good Agreement

This article presents experimental results of determining the friction factors for two microchannels with circular crosssection: rectilinear and curvilinear. The inner diameter of channels in both cases was 100 microns. The Reynolds numbers ranged from 110 to 2216. Pressure measurement was carried out simultaneously in four locations along the channel. Friction factor for the straight microchannel was in good agreement with the theoretical value for the round smooth tubes. For the curved microchannel, the value of friction factor of the curved section was 17 percent less than the reference value for smoothly curved tubes. The experimental results are compared with calculations which were made using the software package Fluent

Numerical and Experimental Analysis of Turbulent Flow in Corrugated Pipes

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Henrique Stel ◽  
Rigoberto E. M. Morales ◽  
Admilson T. Franco ◽  
Silvio L. M. Junqueira ◽  
Raul H. Erthal ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Velocity Magnitude ◽  
Geometric Configurations ◽  
Corrugated Surfaces ◽  
Friction Factors

This article describes a numerical and experimental investigation of turbulent flow in pipes with periodic “d-type” corrugations. Four geometric configurations of d-type corrugated surfaces with different groove heights and lengths are evaluated, and calculations for Reynolds numbers ranging from 5000 to 100,000 are performed. The numerical analysis is carried out using computational fluid dynamics, and two turbulence models are considered: the two-equation, low-Reynolds-number Chen–Kim k-ε turbulence model, for which several flow properties such as friction factor, Reynolds stress, and turbulence kinetic energy are computed, and the algebraic LVEL model, used only to compute the friction factors and a velocity magnitude profile for comparison. An experimental loop is designed to perform pressure-drop measurements of turbulent water flow in corrugated pipes for the different geometric configurations. Pressure-drop values are correlated with the friction factor to validate the numerical results. These show that, in general, the magnitudes of all the flow quantities analyzed increase near the corrugated wall and that this increase tends to be more significant for higher Reynolds numbers as well as for larger grooves. According to previous studies, these results may be related to enhanced momentum transfer between the groove and core flow as the Reynolds number and groove length increase. Numerical friction factors for both the Chen–Kim k-ε and LVEL turbulence models show good agreement with the experimental measurements.

Rayleigh Step Journal Bearing: Part 1—Compressible Fluid

1968 ◽  
Vol 90 (1) ◽  
pp. 271-280 ◽  
Author(s):  
B. J. Hamrock
Keyword(s):  
Compressible Fluid ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Pressure Profile ◽  
Clearance Ratio ◽  
Attitude Angle ◽  
Step Parameters ◽  
Bearing Part

A linearized PH solution to the Reynolds equation was obtained while neglecting side leakage. The analysis was divided into two parts—the step and ridge regions. The pressure profile across the step and ridge region of the various pads which are placed around the journal was obtained from the linearized PH Reynolds equation. Knowing the pressure, the load components and attitude angle were calculated. The resulting equations were found to be a function of the bearing parameters (the eccentricity and compressibility number) and the step parameters (ratio of the stepped clearance to the ridge clearance, ratio of the angle extended by the ridge to the angle extended by the pad, and number of pads placed around the journal). The maximum load capacity can be determined by numerically differentiating the load with respect to the step bearing parameters while finding where the slope is zero. A series of data was run while varying the bearing parameters. The attitude angle was calculated for the various cases which were run.

Optimization of Clearance in a Squeeze-Film Journal Bearing

1971 ◽  
Vol 93 (2) ◽  
pp. 246-251
Author(s):  
C. L. Strodtman
Keyword(s):  
Numerical Methods ◽  
Small Parameter ◽  
Shape Factor ◽  
Journal Bearing ◽  
Diameter Ratio ◽  
Parameter Analysis ◽  
Squeeze Film ◽  
Clearance Ratio ◽  
Proper Selection ◽  
Selection Of

It is shown that a squeeze-film journal bearing supporting a mass completely contained within the bearing can be designed with the optimum value of minimum clearance by proper selection of the drive amplitude to nominal clearance ratio, the length to diameter ratio, and the shape factor of the excursion. Both a small parameter and an augmented, small parameter analysis are given. In the latter case, numerical methods are employed to solve the resulting equations. The results of the analysis are illustrated in application to an accelerometer design.

Paper 9: Dynamic Hybrid Bearing Characteristics of Annular Controlled Leakage Seals

1969 ◽  
Vol 184 (14) ◽  
pp. 92-100 ◽  
Author(s):  
H. F. Black ◽  
D. N. Jenssen
Keyword(s):  
Considerable Effect ◽  
Diameter Ratio ◽  
Experimental Results ◽  
Precise Analysis ◽  
Theoretical Predictions ◽  
Paper Form ◽  
Linear Effects ◽  
Dynamic Components ◽  
Dynamic Hybrid ◽  
Length To Diameter Ratio

The dynamic bearing characteristics of plain seals having appreciable length-to-diameter ratio are analysed by a perturbation method giving linear results. Non-linear effects have been treated in a more precise analysis, and a summary of the method and comparison of results with the simpler linear results is given. Some experimental results are given and compared with theoretical predictions. It is shown that length-to-diameter ratio has a considerable effect on seals of appreciable length, e.g. balance pistons, and that dynamic components of bearing action due to shaft rotation are comparable with the purely hydrostatic centring forces. Experimental results are shown to be reasonably in agreement with theory. It is concluded that the linearized bearing coefficients of seals given in this paper form a sufficiently sound basis for use in the vibrations analysis of pump rotors.

Paper 10: A Hydrodynamic Pocket Journal Bearing

1969 ◽  
Vol 184 (12) ◽  
pp. 70-74
Author(s):  
D. F. Sheldon ◽  
J. P. O'Donoghue ◽  
C. J. Hooke
Keyword(s):  
High Pressure ◽  
Journal Bearing ◽  
Load Capacity ◽  
Control Device ◽  
Experimental Results ◽  
Alternative Mode ◽  
Hydrostatic Bearing ◽  
Operating Range ◽  
Mode Of Operation ◽  
Return Valve

The authors present theoretical and experimental results for a hydrodynamic pocket bearing. The bearing has a geometry similar to that of a conventional hydrostatic bearing, but no control device is incorporated in the supply line other than a non-return valve which prevents the leakage of fluid from those pockets where a pressure is generated. The load capacity of such bearings is greater than that of a circumferentially grooved hydrostatic bearing over the operating range of eccentricity tested by the authors, and is much greater than that of two short hydrodynamic bearings equal to the side sealing lands. Because of this the bearing offers a useful alternative mode of operation for a bearing (externally pressurized) which suffers a loss of its high-pressure oil supply.

Turbulent Hybrid Bearings With Fluid Inertia Effects

1990 ◽  
Vol 112 (4) ◽  
pp. 699-707 ◽  
Author(s):  
Luis San Andre´s
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Pressure Rise ◽  
Reynolds Numbers ◽  
Dynamic Force ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Friction Factors ◽  
Region Flow ◽  
The Stability

High speed hybrid bearings for cryogenic applications demand large levels of external pressurization to provide substantial load capacity. These conditions give rise to large film Reynolds numbers, and thus, cause the fluid flow within the bearing film to be turbulent and dominated by fluid inertia effects both at the recess edges and at the thin film lands. The analysis includes the effect of recess fluid compressibility and a model for the pressure rise within the recess region. Flow turbulence is simulated by friction factors dependent on the local Reynolds numbers and surface conditions. A perturbation method is used to calculate the zeroth and first flow fields and determine the bearing steady-state and dynamic force response. Comparison of results with existing experimental data shows the accuracy of the present full inertial-turbulent analysis. A roughened bearing surface is shown to improve considerably the stability characteristics of hybrid bearings operating at high speeds.

Theory and Experiments of Squeeze-Film Gas Bearings: Part 1—Cylindrical Journal Bearing

1966 ◽  
Vol 88 (1) ◽  
pp. 191-198 ◽  
Author(s):  
C. H. T. Pan ◽  
S. B. Malanoski ◽  
P. H. Broussard ◽  
J. L. Burch
Keyword(s):  
Experimental Data ◽  
Journal Bearing ◽  
Approximate Analytical Solution ◽  
Load Capacity ◽  
Squeeze Film ◽  
Radial Load ◽  
Radial Stiffness ◽  
Theoretical Predictions ◽  
Gas Journal Bearing ◽  
Theory And Experiments

An asymptotic analysis for the cylindrical squeeze-film gas journal bearing has been formulated. An approximate analytical solution is presented. Load-deflection experiments have been performed on a double-film, squeeze-film gas journal bearing. The experimental data confirm the theoretical predictions. Design curves are given for the steady-state radial load capacity and radial stiffness of the cylindrical gas journal bearing.

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