Turbulent fluid flow and heat transfer in concentric annuli with moving cores

Shigechi, Toru; Kawae, Nobuji; Lee, Y.

doi:10.1016/0017-9310(90)90232-j

Cited by 19 publications

(14 citation statements)

References 10 publications

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“…At very high core velocities, however, it was observed that the friction factor was increased by the eccentric position of the core. In the turbulent model for concentric annular flow with axially moving core Shigechi, Kawae & Lee (1990) derived analogous influences of the parameters as in the laminar flow. Shear forces on the core surface which result in an axial force component were not considered in these investigations.…”

Section: Moving Cores In Pipe Flowmentioning

confidence: 99%

Thread-annular flow in vertical pipes

2000

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Thread injection is a promising method for different minimally invasive medical applications. This paper documents an experimental study dealing with an axially moving thread in annular pipe flow. Mass flow and axial force on the thread are measured for a 0.46 mm diameter thread in pipes with diameters between 0.55 and 1.35 mm. The experiments with thread velocities of up to 1.5 ms−1 confirm the findings of theoretical studies that for clinical requirements the radius ratio between thread and pipe is crucial for the adjustments of mass ow and force on the thread.In both regimes, laminar and turbulent flow, the thread shows a characteristic oscillatory behaviour without touching the pipe wall. Resonance-like oscillations indicate circular thread motions around the pipe centre. The oscillating eccentricities may arise from longitudinal inhomogeneities of the thread shape and flow disturbances which cause non-stationary lateral momenta. According to established findings on annular flow with eccentric cylinders we assume that the mass flow, which is high compared to the concentric model, is caused by the temporary thread eccentricities. These findings should be considered in clinical applications to avoid possible thread blockage due to resonance-like vibrations.

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Section: Moving Cores In Pipe Flowmentioning

confidence: 99%

Thread-annular flow in vertical pipes

2000

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“…the Jacobian matnx can be evaluated using and (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20).…”

Section: Finite Element Formulationmentioning

confidence: 99%

“…xr(2)=0.0 ,2,6,9,9,6,3.7/ DATA IC19,63,7,8,9,7,4/ DATA ID/8,9,7,4.1 3.9.81 DATA If/5,2.6,9,8,9,7.4/ DATA IQ/1$, 9.8,9,6,3 ((X(l.72)-X(l.2))**2.+ (X(2,72)-X(2.2)…”

Section: Ewc=vis/denmentioning

confidence: 99%

Turbulent fluid flow, heat transfer and onset of nucleate boiling in annular finned passages

Shim

Soliman

Sims

2000

International Journal of Thermal Sciences

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The author has granted a nonexclusive licence allowing the National Library of Canada to reproduce, loaq distribute or seil copies of this thesis in microform, paper or electronic formats. The author retains ownership of the copyright in this thesis. Neither the thesis nor substantial extracts fiom it may be printed or otherwise reproduced without the author's permission. TEE UNIVERSITY OF MANITOBA FACULTY OF GRADUATE STUDIES COPYRlCaT PERMISSION A Thwis/Pneticum submittai to the Faculty of Graduate Studies of the University of Manitoba in partial fulfiillment of the nquirements for the degrcc of Permission bas k e n granted to the LIBRARY OF THE UNIVERSITY OF MANITOBA to lend or seIl copies of tbù tbesis/practicum, to the NATIONAL LIBRARY OF CANADA to microfilm this thcsidpracticum and to lend or sel1 copies of the film, and to UNIVERSITY MICROFILMS INC. to publisb an abstract of this thcsis/pmcticum.. This reproduction or copy of this thais has bccn made available by authority of the copyright owner solely for tbe purpose of private study and research, and may only be reproduced and copied as permitted by copyright L w s or witb express writtcn authorization from the copyright owuer. 1 would like ta convey my sincece appreciation to my advisors at the University of Manitoba, Professors Soliman, H.M. and Sims, GE. for their guidance and encouragement throughout the course of the work. 1 would like to thank Professor Britton, M. of the University of Manitoba, and Dr. Krishnan, V.S. and Mr. Richards, D.J. of Atomic Energy of Canada Limited for their keen interest and for providing usefbl cornments through the Advisory Cornmittee. 1 would also like to thank Dr. Kowalski, J.E. of Atomic Energof Canada Limited for providing experimental data for the finned annulus geometries.

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“…They concluded that with increasing moving wall velocity, the friction factor decreases, and the variations of the Nusselt number depend strongly on the thermal boundary conditions. Afterwards, many researchers have emphasized this concept and the details can be found in the existing literature [38][39][40]. Nevertheless, to the best of the author's knowledge, no study to date has examined the effects of adding nanoparticles inside a concentric annulus with a moving core.…”

Section: Introductionmentioning

confidence: 98%

Effects of Nanoparticle Migration on Water/Alumina Nanofluid Flow Inside a Horizontal Annulus with a Moving Core

Malvandi¹,

Ganji²

2014

J. mech.

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The present study is a theoretical investigation of the laminar flow and convective heat transfer of water/alumina nanofluid inside a horizontal annulus with a streamwise moving inner cylinder. A modified, two-component, four-equation, nonhomogeneous equilibrium model is employed for the alumina/water nanofluid, which fully accounts for the effect of the nanoparticle volume fraction distribution. To determine the effects of thermal boundary conditions on the migration of the nanoparticles, two cases are considered: constant heat flux at the outer wall with an adiabatic inner wall (Case A) and constant heat flux at the inner wall with an adiabatic outer wall (Case B). The numerical results indicate that the thermal boundary conditions at the pipe walls significantly affect the nanoparticle distribution, particularly in cases where the ratio of Brownian motion to thermophoretic diffusivities is small. Moreover, increasing the velocity of the moving inner cylinder reduces the heat transfer rate for Case A. Conversely, in Case B, the movement of the inner cylinder enhances the heat transfer rate, and anomalous heat transfer enhancement occurs when the thermophoretic force is dominant (in larger nanoparticles).

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Turbulent fluid flow and heat transfer in concentric annuli with moving cores

Cited by 19 publications

References 10 publications

Thread-annular flow in vertical pipes

Thread-annular flow in vertical pipes

Turbulent fluid flow, heat transfer and onset of nucleate boiling in annular finned passages

Effects of Nanoparticle Migration on Water/Alumina Nanofluid Flow Inside a Horizontal Annulus with a Moving Core

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