Convective heat-mass transfer in the entrance region of a concentric annulus having a rotating inner cylinder

Molki, Majid; Astill, K. N.; Leal, Elba Gomes dos Santos

doi:10.1016/0142-727x(90)90005-v

Cited by 22 publications

(7 citation statements)

References 8 publications

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“…The higher the rotation speed, the more rapidly Nu tends to reach its numerical limit. This observation is apparently confirmed by the results reported by Molki et al [59], who worked on mass transfer (naphthalene) with an air flow of which the input had been controlled in such a way as to reduce the dimensions of the zone preceding the cylindrical gap. It should nonetheless be noted that the cylindrical gap is proportionately much shorter than the one presented by Hirai et al [60] and consequently does not quite allow for developed flow to be reached.…”

Section: 221supporting

confidence: 88%

“…Molki et al [59] likewise observed, with an adequately high Taylor number (higher than Ta c ) the appearance of vortices at a distance from the cylindrical gap entrance proportionally as sizable as Re a . Hasoon and Martin [55] have likewise shown that the critical Taylor number decreases in accordance with distance from the cylindrical gap entrance.…”

Section: Influence Of Rotation: Taylor Vortex Flow Transitionmentioning

confidence: 83%

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A review of heat transfer between concentric rotating cylinders with or without axial flow

Fénot

Bertin

Dorignac

et al. 2011

International Journal of Thermal Sciences

179

122

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Section: 221supporting

confidence: 88%

Section: Influence Of Rotation: Taylor Vortex Flow Transitionmentioning

confidence: 83%

A review of heat transfer between concentric rotating cylinders with or without axial flow

Fénot

Bertin

Dorignac

et al. 2011

International Journal of Thermal Sciences

179

122

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“…Second, Fig. 3 presents the comparison of the Sherwood number along the parameter h (z / D ReSc) with that obtained with the correlation reported in Molki et al (1990) for Ta=0, Re=120, η=0.5 and n=1. The result reveals a good agreement.…”

Section: Numerical Resultsmentioning

confidence: 81%

Numerical Study of the Effect of a Power-law Fluid Flow Structures on Levels of Mixing in a Taylor Couette Configuration

2023

JAFM

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This work is a numerical study on the effects of the flow structures of the power-law fluid between two concentric cylinders with an upward laminar axial flow on levels of mixing and mean residence time through the Taylor Couette system. The cylindrical annular duct presents a radius ratio of 0.5 and an aspect ratio of 8. The inner cylinder is rotating while the outer one is kept at rest. The residence time distributions (R.T.D.) method and the mean residence time (Tm) are used to determine the number of tanks in series and the dispersion coefficient to evaluate levels of mixing. To this end, a pulsed input injection of a tracer is computing at the outlet of the annulus. As a main objective of this study, is to analyze the effect of the flow structure of a power-law fluid between two concentric cylinders on the mixing level and mean residence time in a Taylor Couette system. The novelty of our work is the use of power-law fluids as particles-carrying fluids. Several parameters, such as the axial Reynolds number (Re), the Taylor number (Ta), and the power-law index behavior (n), are used to show their impact on levels of mixing. It is shown that when n increases, the number of stirred tanks in series N increases for pseudoplastic fluids (n<1), indicating low levels of mixing while the parameter (N) decreases for dilatants fluids (n>1), revealing high levels of mixing. The increase of the power-law index in the range of 0.6<n<1 decreases the dispersion coefficient, indicating the non-ideal mixing in the duct. In addition, for further increase of the power-law index in the range of n>1 increases the dispersion coefficient points to the well-mixing.

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“…[6] investigated flow instabilities that occur in the flow between rotating cylinders. [7] studied the effect of the gab entrance region and showed that it is similar to the entrance region of a pipe or a duct. [8] studied the effect of adding slots to the motor stator on the rate of heat transfer to the flow in the annular gap.…”

Section: Introduction and Literature Reviewmentioning

confidence: 99%

Heat Transfer Inside an Electric Motor

Teamah¹,

Hamed²

2022

International Conference on Fluid Flow, Heat and Mass Transfer

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Convection heat transfer from an axial air flow inside the gap between the rotor and the stator of a four-pole surface permanent magnet (SPM) electric motor has been investigated. All surfaces considered smooth with heat is being generated within the rotor while the stator is considered insulated. This study has been carried out numerically using ANSYS-CFX. The effect of the axial flow and rotational speed on the average Nusselt number has been investigated in terms of the axial and rotational Reynolds numbers in the range of 2140-6420 and 1750-27000, respectively. Numerical results have been validated using experimental data and found in reasonable agreement. Results show that the effect of the axial Reynolds number is more dominant than that of the rotational Reynolds number.

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Convective heat-mass transfer in the entrance region of a concentric annulus having a rotating inner cylinder

Cited by 22 publications

References 8 publications

A review of heat transfer between concentric rotating cylinders with or without axial flow

A review of heat transfer between concentric rotating cylinders with or without axial flow

Numerical Study of the Effect of a Power-law Fluid Flow Structures on Levels of Mixing in a Taylor Couette Configuration

Heat Transfer Inside an Electric Motor

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