The Effect of Taylor Vortex Flow on the Development Length in Concentric Annuli

1979 ◽  
Vol 21 (2) ◽  
pp. 59-64 ◽  
Author(s):  
D. A. Simmers ◽  
J. E. R. Coney
Keyword(s):  
Reynolds Number ◽  
Vortex Flow ◽  
Outer Cylinder ◽  
Outer Wall ◽  
Taylor Vortex ◽  
Rotational Flow ◽  
Development Length ◽  
Full Development ◽  
Annular Gap ◽  
Taylor Vortex Flow

Results are presented of an investigation into a developing, combined axial and rotational flow in an annular gap formed by a stationary outer cylinder and a rotatable inner cylinder for an annulus radius ratio of 0–8 and an axial Reynolds number of 1200. These results show that, in the Taylor vortex flow régime, the development length decreases with the parameter Re2a/Ta and that the greatest development length in an annular gap, for a given axial Reynolds number, occurs when the Taylor number is near to its critical value. Consideration of isothermal heat transfer through the outer wall of the annular gap suggests that, in the development of the flow, the Nusselt number rises to a high value before falling to a constant value, at full development.

Experimental Study of Axial Slit Wall Effect on Taylor-Couette Flow

2007 ◽  
Author(s):  
Sang-Hyuk Lee ◽  
Hyoung-Bum Kim
Keyword(s):  
Reynolds Number ◽  
Couette Flow ◽  
Vortex Flow ◽  
Outer Cylinder ◽  
Velocity Fields ◽  
Taylor Vortex ◽  
Stable Mode ◽  
Taylor Vortex Flow ◽  
Taylor Couette ◽  
Taylor Couette Flow

Taylor-Couette flow has been studied extensively and lots of variables which affect the flow instability are being reported. The wall geometry effect of Taylor-Couette flow, however, has been less studied. In this study, we investigated the effect of axial slit of outer cylinder. This kind of configuration can be easily seen in rotating machinery. Particle image velocimetry method was used to measure the velocity fields in longitudinal and latitudinal planes. The index matching method was used to avoid light refraction. The velocity fields between the slit and plain model which has the smooth wall were compared. From the experiments, both models have the same flow mode below Re = 143. The transition from circular Couette flow to plain Taylor vortex flow began at Re = 103, and the next transition to wavy vortex flow occurred at 124. The effect of slit wall appeared when the Reynolds number is larger than Re = 143. Above this Reynolds number, there was no stable mode and plain and wavy Taylor vortex flow randomly appeared.

Flow Regimes in Two-Phase Hexane/Water Semibatch Vertical Taylor Vortex Flow

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Charlton Campbell ◽  
Michael G. Olsen ◽  
R. Dennis Vigil
Keyword(s):  
Vortex Flow ◽  
Axial Flow ◽  
Reynolds Numbers ◽  
Flow Patterns ◽  
Water Phase ◽  
Taylor Vortex ◽  
Two Phase ◽  
Annular Gap ◽  
Taylor Vortex Flow ◽  
Regime Map

Optical-based experiments were carried out using the immiscible pair of liquids hexane and water in a vertically oriented Taylor–Couette reactor operated in a semibatch mode. The dispersed droplet phase (hexane) was continually fed and removed from the reactor in a closed loop setup. The continuous water phase did not enter or exit the annular gap. Four distinct flow patterns were observed including (1) a pseudo-homogenous dispersion, (2) a weakly banded regime, (3) a horizontally banded dispersion, and (4) a helical flow regime. These flow patterns can be organized into a two-dimensional regime map using the azimuthal and axial Reynolds numbers as axes. In addition, the dispersed phase holdup was found to increase monotonically with both the azimuthal and axial Reynolds numbers. The experimental observations can be explained in the context of a competition between the buoyancy-driven axial flow of hexane droplets and the wall-driven vortex flow of the continuous water phase.

Numerical Study of Effects of Initial Flow Field on Taylor Vortex Flow

2007 ◽  
Author(s):  
H. Furukawa ◽  
M. Hanaki ◽  
T. Watanabe
Keyword(s):  
Flow Field ◽  
Vortex Flow ◽  
Numerical Study ◽  
Outer Cylinder ◽  
Visual Observation ◽  
Taylor Vortex ◽  
Initial Flow ◽  
Taylor Vortex Flow ◽  
The Difference ◽  
Mode Formation

In concentrically rotating double cylinders consisting of a stationary outer cylinder and a rotating inner cylinder, Taylor vortex flow appears. Taylor vortex flow occurs in journal bearings, various fluid machineries, containers for chemical reaction, and other rotating components. Therefore, the analysis of the flow structure of Taylor vortex flow is highly effective for its control. The main parameters that determine the modes of Taylor vortex flow of a finite length are the aspect ratio Γ, Reynolds number Re. Γ is defined as the ratio of the cylinder length to the gap length between cylinders, and Re is determined on the basis of the angular speed of the inner cylinder. Γ was set to be 3.2, 4.8 and 6.8, and Re to be values in the range from 100 to 1000 at intervals of 100. Thus far, a large number of studies on Taylor vortex flow have been carried out; however, the effects of the differences in initial conditions have not yet been sufficiently clarified. In this study, we changed the initial flow field between the inner and outer cylinders in a numerical analysis, and examined the resulting changes in the mode formation and bifurcation processes. In this study, the initial speed distribution factor α was defined to be a function of the initial flow field and set to be 1.0, 0.999, 0.9 and 0.8 for the calculation. As a result, a difference was observed in the final mode depending on the difference in α for each Γ. From this finding, non-uniqueness, which is a major characteristic of Taylor vortex flow, was confirmed. However, no regularities regarding the difference in mode formation were found and the tendency of the mode formation process was not specified. Moreover, the processes of developing the vortex resulting in different final modes were monitored over time by visual observation. Similar flow behaviors were initially observed after the start of the calculation. Then, a bifurcation point, at which the flow changed to a mode depending on α, was observed, and finally the flow became steady. In addition, there was also a difference in the time taken for the flow to reach the steady state. These findings are based on only visual observation. Accordingly, a more detailed analysis at each lattice point and a comparison of physical quantities, such as kinetic energy and enstrophy, will be our future tasks.

Forming Process of Taylor Vortex Flow of Polymer Solutions

2004 ◽  
Author(s):  
Shu Sumio ◽  
Keizo Watanabe ◽  
Satoshi Ogata
Keyword(s):  
Reynolds Number ◽  
Flow Visualization ◽  
Vortex Flow ◽  
Polymer Solutions ◽  
Newtonian Fluids ◽  
Experimental Result ◽  
Taylor Vortex ◽  
Number Range ◽  
Primary Mode ◽  
Taylor Vortex Flow

The laser-induced fluorescence (LIF) technique carried out the flow visualization for the formation of Taylor vortex, which occurred in the gap between the two coaxial cylinders. The test fluids were tap water and glycerin 60wt% solution as Newtonian fluids. Polyacrilamide (SeparanAP-30) solutions in the concentration range of 10 ppm to 1000 ppm and polyethylene-oxide (PEO15) solutions in the range of 20 ppm to 1000 ppm were tested as non-Newtonian fluids, respectively. The Reynolds number range was 80 < Re < 4.0 × 103 in the experiment. The rotating inner cylinder was accelerated under the slow condition (dRe*/ dt ≤ 1 min−1) in order to obtain a Taylor vortex flow of the stable primary mode. Flow visualization results showed that the Go¨rtler vortices of half the number of Taylor cells occurred in the gap when Taylor vortex flow of the primary mode was formed. In addition, the critical Reynolds number of the polymer solutions case, which Taylor vortices occur, because the generation of the Go¨rtler vortices was retarded. At the higher concentration of the polymer solutions, this effect became remarkable. Measurements of steady-state Taylor cells showed that the upper and the lower cells of polymer solutions became larger in wavelength than that of the Newtonian fluids. The Taylor vortex flow of non-Newtonian fluids was analyzed and the result of the Giesekus model agreed with the experimental result.

An Experimental Investigation of the Stability of Spiral Vortex Flow

1979 ◽  
Vol 21 (6) ◽  
pp. 397-402 ◽  
Author(s):  
M. M. Sorour ◽  
J. E. R. Coney
Keyword(s):  
Vortex Flow ◽  
Outer Cylinder ◽  
Axial Flow ◽  
Reynolds Numbers ◽  
Taylor Vortex ◽  
Vortex Cell ◽  
Annular Gap ◽  
Spiral Vortex ◽  
Axial Pressure Gradient ◽  
The Stability

The hydrodynamic stability of the flow in an annular gap, formed by a stationary outer cylinder and a rotatable inner cylinder, through which an axial flow of air can be imposed, is studied experimentally. Two annulus radius ratios of 0.8 and 0.955 are considered, representing wide- and narrow-gap conditions, respectively. It is shown that, when a large, axial pressure gradient is superimposed on the tangential flow induced by the rotation of the inner cylinder, the characteristics of the flow at criticality change significantly from those at zero and low axial flows, the axial length and width of the resultant spiral vortex departing greatly from the known dimensions of a Taylor vortex cell at zero axial flow. Also, the drift velocity of the spiral vortex is found to vary with the axial flow. Axial Reynolds numbers, Rea, of up to 700 are considered.

Numerical Simulation of Taylor Vortex Flow by GDQ Method

2000 ◽  
Author(s):  
L. Wang ◽  
C. Shu ◽  
Y. T. Chew
Keyword(s):  
Vortex Flow ◽  
Stokes Equations ◽  
Outer Cylinder ◽  
Three Dimensional ◽  
Computational Effort ◽  
Numerical Results ◽  
Numerical Code ◽  
Taylor Vortex ◽  
Specific Flow ◽  
Taylor Vortex Flow

Abstract In this study, the GDQ method was used to simulate a specific flow regime, Taylor vortex flow, of the motion of fluids between two concentric cylinders with rotating inner cylinder and stationary outer cylinder. An approach combining the SIMPLE strategy and GDQ discretization based on non-staggered mesh was proposed to solve the time-dependent, three-dimensional incompressible Navier-Stokes equations in primitive variable form. The numerical solution obtained has the accuracy of second-order in temporal discretization and high-order in spatial discretization. Also, this numerical code may allow the direct numerical simulations for the various regimes of Couette-Taylor flow problem. The performance of this approach was studied through a test case of Taylor vortex flow. The reported numerical results were compared with those from others. For this approach, accurate numerical results can be obtained by using fewer grid points compared with low-order methods. As a consequence, the computational effort can be greatly reduced.

Experimental Study on Oscillatory Couette-Taylor Flows Behaviour

2013 ◽  
Author(s):  
Emna Berrich ◽  
Fethi Aloui ◽  
Jack Legrand
Keyword(s):  
Mass Transfer ◽  
Angular Velocity ◽  
Time Evolution ◽  
Vortex Flow ◽  
Outer Cylinder ◽  
Taylor Vortex ◽  
Shear Rates ◽  
Taylor Vortices ◽  
Taylor Vortex Flow ◽  
Wall Shear

In the simplest and original case of study of the Taylor–Couette TC problems, the fluid is contained between a fixed outer cylinder and a concentric inner cylinder which rotates at constant angular velocity. Much of the works done has been concerned on steady rotating cylinder(s) i.e. rotating cylinders with constant velocity and the various transitions that take place as the cylinder(s) velocity (ies) is (are) steadily increased. On this work, we concentrated our attention in the case in which the inner cylinder velocity is not constant, but oscillates harmonically (in time) clockwise and counter-clockwise while the outer cylinder is maintained fixed. Our aim is to attempt to answer the question if the modulation makes the flow more or less stable with respect to the vortices apparition than in the steady case. If the modulation amplitude is large enough to destabilise the circular Couette flow, two classes of axisymmetric Taylor vortex flow are possible: reversing Taylor Vortex Flow (RTVF) and Non-Reversing Taylor Vortex Flow (NRTVF) (Youd et al., 2003; Lopez and Marques, 2002). Our work presents an experimental investigation of the effect of oscillatory Couette-Taylor flow, i.e. both the oscillation frequency and amplitude on the apparition of RTVF and NRTVF by analysing the instantaneous and local mass transfer and wall shear rates evolutions, i.e. the impact of vortices at wall. The vortices may manifest themselves by the presence of time-oscillations of mass transfer and wall shear rates, this generally corresponds to an instability apparition even for steady rotating cylinder. On laminar CT flow, the time-evolution of wall shear rate is linear. It may be presented as a linear function of the angular velocity, i.e. the evolution is steady even if the angular velocity is not steady. At a “critical” frequency and amplitude, the laminar CT flow is disturbed and Taylor vortices appear. Comparing to a steady velocity case, oscillatory flow accelerate the instability apparition, i.e. the critical Taylor number corresponds to the transition is smaller than that of the steady case. For high oscillation amplitudes of the inner cylinder rotation, the mass transfer time-evolution has a sinusoidal evolution with non equal oscillation amplitudes. If the oscillation amplitude is large enough, it can destabilize the laminar Couette flow, Taylor vortices appears. The vortices direction can be deduced from the sign of the instantaneous wall shear rate time evolution.

The Effect of Taylor Vortex Flow on the Radial Forces in an Annulus Having Variable Eccentricity and Axial Flow

1978 ◽  
Vol 100 (2) ◽  
pp. 210-214 ◽  
Author(s):  
J. E. R. Coney ◽  
J. Atkinson
Keyword(s):  
Vortex Flow ◽  
Outer Cylinder ◽  
Axial Flow ◽  
Reynolds Numbers ◽  
Radial Force ◽  
Taylor Vortex ◽  
Eccentric Annulus ◽  
Taylor Vortex Flow ◽  
Radial Forces ◽  
Force Variation

Results are presented in dimensionless form as obtained in an experimental study of the resultant radial force variation in an eccentric annulus formed by a stationary outer cylinder and a rotating inner cylinder, through which an axial flow of oil may be pumped. Two eccentricity ratios, 0.5 and 0.9, and three axial Reynolds numbers for the flow of the fluid in the annulus, 0, 25, and 50, are considered. It is shown that the onset of Taylor vortex flow has a marked effect on the magnitude and direction of the resultant radial force. The resultant forces and attitude angles are compared with those derived from Sommerfeld’s journal bearing theory. Comparisons are also made between critical Taylor numbers for the present investigation and those available in the literature.

Formation of Taylor Vortex Flow of Polymer Solutions

2005 ◽  
Vol 128 (1) ◽  
pp. 95-100 ◽  
Author(s):  
Keizo Watanabe ◽  
Shu Sumio ◽  
Satoshi Ogata
Keyword(s):  
Reynolds Number ◽  
Flow Visualization ◽  
Vortex Flow ◽  
Polymer Solutions ◽  
Newtonian Fluids ◽  
Taylor Vortex ◽  
Primary Mode ◽  
Görtler Vortices ◽  
Taylor Vortex Flow ◽  
Gortler Vortices

Laser-induced fluorescence (LIF) was applied for the flow visualization of the formation of a Taylor vortex, which occurred in the gap between two coaxial cylinders. The test fluids were tap water and glycerin 60 %wt solution as Newtonian fluids; polyacrilamide (SeparanAP-30) solutions in the concentration range of 10 to 1000ppm and polyethylene-oxide (PEO15) solutions in the range of 20 to 1000ppm were tested as non-Newtonian fluids. The Reynolds number range in the experiment was 80<Re<4.0×103. The rotating inner cylinder was accelerated under the slow condition (dRe*∕dt⩽1min−1) in order to obtain a Taylor vortex flow in stable primary mode. Flow visualization results showed that the Görtler vortices of half the number of the Taylor cells occurred in the gap when the Taylor vortex flow was formed in the primary mode. In addition, the critical Reynolds number of the polymer solutions increased, where Taylor vortices occur, because the generation of the Görtler vortices was retarded. In high concentration polymer solutions, this effect became remarkable. Measurements of steady-state Taylor cells showed that the upper and lower cells of polymer solutions became larger in wavelength than those of the Newtonian fluids. The Taylor vortex flow of non-Newtonian fluids was analyzed and the result obtained using the Giesekus model agreed with the experimental result.

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