A numerical study of the similarity of fully developed laminar flows in orthogonally rotating rectangular ducts and stationary curved rectangular ducts of arbitrary aspect ratio

Lee, G. H.; Baek, Je Hyun

doi:10.1007/s00466-002-0332-0

Cited by 10 publications

(8 citation statements)

References 28 publications

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“…Later the morphological understanding was broadened by Bara et al [8], Chen and Jan [21], Finlay and Nandakumar [22], Hatzikonstantinou and Sakalis [23], Ishigaki [24], Tiwari et al [25] and Kao [26]. Comparative studies have been done by Jayanti and Hewitt [27], Lee and Baek [28] or Yang and Wang [29]. One of the most comprehensive study has been provided by Mondal et al [30].…”

Section: Introductionmentioning

confidence: 95%

Bifurcation and stability analysis of laminar flow in curved ducts

Machane¹

2009

Numerical Methods in Fluids

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SUMMARYThe development of viscous flow in a curved duct under variation of the axial pressure gradient q is studied. We confine ourselves to two-dimensional solutions of the Dean problem. Bifurcation diagrams are calculated for rectangular and elliptic cross sections of the duct. We detect a new branch of asymmetric solutions for the case of a rectangular cross section. Furthermore we compute paths of quadratic turning points and symmetry breaking bifurcation points under variation of the aspect ratio ( = 0.8 ... 1.5). The computed diagrams extend the results presented by other authors. We succeed in finding two origins of the Hopf bifurcation. Making use of the Cayley transformation, we determine the stability of stationary laminar solutions in the case of a quadratic cross section. All the calculations were performed on a parallel computer with 32×32 processors.

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Section: Introductionmentioning

confidence: 95%

Bifurcation and stability analysis of laminar flow in curved ducts

Machane¹

2009

Numerical Methods in Fluids

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“…It should be noted that in Equation (10), the Coriolis force is perpendicular to the radial direction of the system’s centrifugal force. The transverse secondary flow accompanied by the streamwise vorticity in the radial straight channel is mainly due to the Coriolis force, while the system’s centrifugal force contributes to drive the stream flow along the channel [ 43 , 44 ]. When examining the effect of the system’s centrifugal force on secondary flows in the circumferential channel section (orthogonal to the radial direction), great care is required because f ω is parallel to f C .…”

Section: Resultsmentioning

confidence: 99%

“…When examining the effect of the system’s centrifugal force on secondary flows in the circumferential channel section (orthogonal to the radial direction), great care is required because f ω is parallel to f C . This effect may be understood based on vorticity consideration by rewriting Equation (2) for a constant angular velocity Ω as [ 43 , 44 ]:

where the centrifugal force is incorporated into the modified pressure p * given by

…”

Section: Resultsmentioning

confidence: 99%

Enhancement of Fluid Mixing with U-Shaped Channels on a Rotating Disc

2020

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In this study, centrifugal microfluidics with a simple geometry of U-shaped structure was designed, fabricated and analyzed to attain rapid and efficient fluid mixing. Visualization experiments together with numerical simulations were carried out to investigate the mixing behavior for the microfluidics with single, double and triple U-shaped structures, where each of the U-structures consisted of four consecutive 90° bends. It is found that the U-shaped structure markedly enhances mixing by transverse secondary flow that is originated from the Coriolis-induced vortices and further intensified by the Dean force generated as the stream turns along the 90° bends. The secondary flow becomes stronger with increasing rotational speed and with more U-shaped structures, hence higher mixing performance. The mixing efficiency measured for the three types of mixers shows a sharp increase with increasing rotational speed in the lower range. As the rotational speed further increases, nearly complete mixing can be achieved at 600 rpm for the triple-U mixer and at 720 rpm for the double-U mixer, while a maximum efficiency level of 83–86% is reached for the single-U mixer. The simulation results that reveal detailed characteristics of the flow and concentration fields are in good agreement with the experiments.

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“…Consequently, subsequent modelling work has focused on the wide-channel analytical model that forms the basis for the work reported here. The fuller model can be a powerful tool to understand quantitatively the deviations from infinite width flow behaviour in actual finite-width rotating spiral channels, including the well-known Coriolis secondary flows (Mori and Nakayama, 1968;Miyazaki, 1971;Draad and Nieuwstadt, 1998;Ishigaki, 1999;Lee and Baek, 2002).…”

Section: Discussionmentioning

confidence: 99%

Hydrodynamic characteristics of a rotating spiral fluid-phase contactor

MacInnes

Zambri

2015

Chemical Engineering Science

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ReuseThis article is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs (CC BY-NC-ND) licence. This licence only allows you to download this work and share it with others as long as you credit the authors, but you can't change the article in any way or use it commercially. More information and the full terms of the licence here: https://creativecommons.org/licenses/ Rotating spiral channels enable any two immiscible fluid phases to flow counter-currently in parallel layers allowing independent control of phase flow rates and layer thicknesses. This opens the possibility of application over the full range of fluid contacting operations, including distillation, absorption, extraction and multiphase reaction with separation. A device has been developed that enables wide-ranging experimental studies to support model refinement and design of first-generation applied devices. In this first work with the new device hydrodynamic characteristics are studied for gas-liquid systems as functions of phase flow rates, rotation rate and liquid viscosity. Measurement of the heavy phase layer thickness, using image analysis based on the Young-Laplace theory for interface shape, and measurement of volume flow rate of each phase and pressure and temperature in the spiral channel allows rigorous comparisons with an existing 'wide-channel' model relating flow rates and layer thicknesses to phase properties, geometry and rotation rate. The measured thickness of the heavy-phase layer is predicted well by the wide-channel model at high rotation and phase flow rates, where the deviation from a uniform layer thickness due to menisci at the channel end walls and interface tilt from gravity are small. At low rotation rates, where significant meniscus height and tilt develop, the layer thickness is over-predicted by the wide channel model. The sub 20 µm heavy-phase layer thicknesses measured suggest operation at optimum thickness is possible with the rotating spiral over a wide range of phase and solute systems.

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A numerical study of the similarity of fully developed laminar flows in orthogonally rotating rectangular ducts and stationary curved rectangular ducts of arbitrary aspect ratio

Cited by 10 publications

References 28 publications

Bifurcation and stability analysis of laminar flow in curved ducts

Bifurcation and stability analysis of laminar flow in curved ducts

Enhancement of Fluid Mixing with U-Shaped Channels on a Rotating Disc

Hydrodynamic characteristics of a rotating spiral fluid-phase contactor

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