The Taylor Vortex Regime in the Flow Between Eccentric Rotating Cylinders

1974 ◽  
Vol 96 (1) ◽  
pp. 127-134 ◽  
Author(s):  
F. R. Mobbs ◽  
M. A. M. A. Younes
Keyword(s):  
Axial Flow ◽  
Journal Bearings ◽  
Transition To Turbulence ◽  
Taylor Vortex ◽  
Rotating Cylinders ◽  
Clearance Ratio ◽  
Taylor Vortices ◽  
Wide Range ◽  
Small Clearance

With the exception of very small clearance ratios, transition to turbulence in journal bearings is likely to be preceded by the appearance of Taylor vortices. The resultant regime may extend over a wide range of Taylor numbers and include transitions to several types of wavy vortex modes. The influence of eccentricity, clearance ratio, and axial flow on the critical Taylor numbers corresponding to the appearance of regular Taylor cells and their subsequent wavy mode transformations is reviewed.

The nonlinear calculation of Taylor-vortex flow between eccentric rotating cylinders

1975 ◽  
Vol 67 (1) ◽  
pp. 85-111 ◽  
Author(s):  
R. C. Diprima ◽  
J. T. Stuart
Keyword(s):  
Nonlinear Stability ◽  
Angular Position ◽  
Taylor Number ◽  
Taylor Vortex ◽  
Perturbation Scheme ◽  
Rotating Cylinders ◽  
Clearance Ratio ◽  
Taylor Vortices ◽  
Taylor Vortex Flow ◽  
Small Parameters

This paper is concerned with the nonlinear stability of the flow between two long eccentric rotating cylinders. The problem, which is of interest in lubrication technology, is an extension both of the authors’ earlier work on the linear eccentric case and of still earlier work by Davey and others on the nonlinear concentric analysis of Taylor-vortex development. There are four parameters which are assumed small in the analysis; they are the mean clearance ratio, the eccentricity, the amount by which the Taylor number exceeds its critical value; and the Taylor-vortex amplitude. Following the earlier work mentioned above, relation-ships are specified between these parameters in order to develop a satisfactory perturbation scheme. Thus a non-local solution is obtained to the nonlinear stability problem, in which the whole flow field is taken into account.Of some importance in the analysis is the fact that it is necessary to allow for the development of a pressure field substantially bigger than that associated with Taylor vortices in the concentric case, owing to the Reynolds lubrication effect in a viscous fluid moving through a converging passage. I n order to achieve this mathematically, it is necessary to solve the continuity equation to a higher order than is necessary for the momentum equations.It is found that the angular position for maximum vortex activity, which is 90° downstream of the maximum gap in the linear case, can taken on any value between 0 and 90°, depending on the value of the supercritical Taylor number. For a particular experiment of Vohr (1968) acceptable agreement is obtained for this angle (50°), though the ‘small’ parameters are somewhat outside the expected range of perturbation theory. Formulae are obtained for the torque and forces acting on the inner cylinder.

Visual Observations and Torque Measurements in the Taylor Vortex Regime Between Eccentric Rotating Cylinders

1971 ◽  
Vol 93 (1) ◽  
pp. 121-129 ◽  
Author(s):  
P. Castle ◽  
F. R. Mobbs ◽  
P. H. Markho
Keyword(s):  
Outer Cylinder ◽  
Taylor Vortex ◽  
Rotating Cylinders ◽  
Taylor Vortices ◽  
Torque Measurements ◽  
Good Agreement ◽  
Visual Observations

The instability of Taylor vortices in the flow between a stationary outer cylinder and an eccentric rotating inner cylinder has been investigated by visual observations and by torque measurements. It is shown that both a “weak” and “strong” wavy mode of instability can be detected by torque measurements, giving critical Taylor numbers in good agreement with visual observations.

Flow Transition Criteria in a Journal Bearing

1974 ◽  
Vol 96 (1) ◽  
pp. 135-140 ◽  
Author(s):  
J. Freˆne ◽  
M. Godet
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Flow Transition ◽  
Clearance Ratio ◽  
Taylor Vortices ◽  
Torque Measurements ◽  
Small Clearance ◽  
Type Flow ◽  
Turbulence Effects ◽  
Transition Criteria

High speed Couette type flow was studied for small clearance ratios (C/R = 0.0055 and 0.0031). Water flow pattern visualiszations and torque measurements were performed. Results show that Taylor vortices occur at values predicted by theory, they precede turbulence effects and cause an increase in torque which depends on the clearance ratio. Transition between vortex and turbulent flow is gradual and appears to depend on the Taylor number. Taylor vortices can be found in plain bearings.

Paper 2: Hydrodynamic Stability of the Flow between Eccentric Rotating Cylinders with Axial Flow: Visual Observations

1969 ◽  
Vol 184 (12) ◽  
pp. 10-17 ◽  
Author(s):  
J. E. R. Coney ◽  
F. R. Mobbs
Keyword(s):  
Hydrodynamic Stability ◽  
High Speed ◽  
Marked Effect ◽  
Axial Flow ◽  
Journal Bearings ◽  
Test Fluid ◽  
Taylor Vortices ◽  
Annulus Flow ◽  
Flow Through ◽  
Paint Pigment

The influence of side leakage on the onset of Taylor vortices in high-speed journal bearings is studied by observing the effects of varying the eccentricity of, and the axial flow through, an annulus. The apparatus permits of both sharp and smooth entries to the annulus. Flow visualization is achieved by means of aluminium paint pigment suspended in the test fluid. It is shown that both the eccentricity and the axial flow have a marked effect on the critical Taylor number. Evidence is presented for the co-existence of two systems of vortices within the annulus.

An Experimental Investigation on the Temperature Distribution in Circular Journal Bearings

1986 ◽  
Vol 108 (4) ◽  
pp. 621-626 ◽  
Author(s):  
Junichi Mitsui ◽  
Yukio Hori ◽  
Masato Tanaka
Keyword(s):  
Experimental Investigation ◽  
Angular Position ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Test Rig ◽  
Clearance Ratio ◽  
Temperature Distributions ◽  
Wide Range ◽  
Lubricant Viscosity ◽  
Good Agreement

The temperature distributions in full circular bearings were measured in a test rig. The effects of journal speed, lubricant viscosity, and clearance ratio on the maximum bearing temperature and its location were discussed. The results were compared with the theoretical analysis by the present authors and good agreement was obtained over the wide range of operating conditions. The maximum bearing temperature is found to increase considerably with the increase of speed or lubricant viscosity and also with the decrease of clearance ratio. Its angular position is found to vary with speed and clearance ratio. These phenomena can be explained by the characteristics of maximum film temperature in the oil film.

Taylor Vortices With Short Rotating Cylinders

1974 ◽  
Vol 96 (1) ◽  
pp. 69-70 ◽  
Author(s):  
J. A. Cole
Keyword(s):  
Vortex Formation ◽  
Vortex Pair ◽  
Taylor Vortex ◽  
Rotating Cylinders ◽  
Taylor Vortices ◽  
Vortex Size ◽  
Annular Clearance

Observations of Taylor vortex formation in a short annular clearance show that the final vortex size varies discontinuously with annulus length, ranging from 75 to 115 percent of the theoretical size, and is apparently determined as vortices spread axially inwards from the ends of the annulus by the minimum survival size of the last-formed vortex pair.

Heat Transfer between Eccentric Rotating Cylinders

1980 ◽  
Vol 102 (2) ◽  
pp. 347-350 ◽  
Author(s):  
M. Singh ◽  
S. C. Rajvanshi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Temperature Distribution ◽  
Prandtl Number ◽  
Energy Equation ◽  
Dimensionless Parameter ◽  
Velocity Ratio ◽  
Rotating Cylinders ◽  
Clearance Ratio ◽  
Small Clearance

The heat transfer between eccentric rotating cylinders is studied using a modified bipolar coordinate system. The energy equation has been solved by expressing the temperature in the form of a perturbation in terms of α, the dimensionless parameter defining the clearance ratio; and Rm, the modified Reynolds number. The effect of Prandtl number, eccentricity and velocity ratio on temperature distribution has been shown graphically. The results are valid for small clearance ratio. There is no restriction on eccentricity.

On the Translatory Whirl Motion of a Vertical Rotor in Plain Cylindrical Gas-Dynamic Journal Bearings

1962 ◽  
Vol 84 (1) ◽  
pp. 152-158 ◽  
Author(s):  
C. H. T. Pan ◽  
B. Sternlicht
Keyword(s):  
Time Dependence ◽  
Reynolds Equation ◽  
Angular Speed ◽  
Journal Bearings ◽  
Fluid Film ◽  
Clearance Ratio ◽  
Gas Dynamic ◽  
Vertical Rotor ◽  
Attitude Angle ◽  
Small Clearance

For the theoretical prediction of the dynamical characteristics of a rotor system, it is necessary to have an accurate knowledge of the bearing fluid film forces under dynamical conditions. With a small clearance ratio and at a moderate speed, the motion of the lubricant is governed by the generalized Reynolds equation. If the lubricant is a gaseous medium, the Reynolds equation is complicated by the compressibility effects, which include nonlinearity and time-dependence under dynamic conditions [1]. In the case of a vertical rotor operating in plain cylindrical journal bearings, the steady whirl approximation is appropriate and time-dependence in the Reynolds equation can be removed by a co-ordinate transformation. The form of the transformed equation is identical to the static Reynolds equation except that the compressibility number is modified by a factor which depends on the angular speed of the whirl motion [2, 3]. The altitude angle, in the presence of the whirling motion, is quite different from the static attitude angle. On the other hand, the magnitudes of the forces are not very different. The steady whirl analysis may be used to determine the synchronous whirl motion of an unbalanced rotor. The phase angle between the fluid film force and the maximum film thickness plane is the complement of the attitude angle according to the quasi-static analysis. Experimental data are in excellent agreement with the results of the steady whirl analysis. Also, the modified compressibility number is reduced to zero at half-frequency whirl, and the Reynolds equation, for an isothermal gaseous film with the small eccentricity ratio approximation, becomes identical to that of the liquid film. Since it has been established that the threshold of half-frequency whirl for vertical rotors operating in plain cylindrical journal bearings is at zero speed in [4], the same conclusion applies to the corresponding gas-dynamic bearing.

An Experimental Study of Taylor Vortices and Turbulence in Flow Between Eccentric Rotating Cylinders

1968 ◽  
Vol 90 (1) ◽  
pp. 285-296 ◽  
Author(s):  
J. H. Vohr
Keyword(s):  
Experimental Study ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Experimental Work ◽  
Reynolds Numbers ◽  
Taylor Vortex ◽  
Rotating Cylinders ◽  
Taylor Vortices ◽  
Torque Measurements ◽  
Factor Data

The critical speeds for onset of Taylor vortices inflow between eccentric rotating cylinders are determined by means of torque measurements for various eccentricity ratios and clearance ratios of the cylinders. Results are compared with the theoretical and experimental work of other investigators. Visual studies are made of the flow in both the Taylor vortex and turbulent flow regimes. Friction factor data are obtained for Reynolds numbers up to 40,000.

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