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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/2862
Title: Numerical simulation of steady flow fields in coiled flow inverter
Authors: Kumar, Vimal
Nigam K.D.P.
Published in: International Journal of Heat and Mass Transfer
Abstract: Flatter velocity profiles and more uniform thermal environments are extremely desirous factors for improved performance in flow reactors and heat exchangers. One means of achieving it in laminar flow systems is to use mixers and flow inverters. In the present study a new device is introduced based on the flow inversion by changing the direction of centrifugal force in helically coiled tubes. The objective of the present study is to characterize flow development and temperature fields in the proposed device made up from the configurations of bent coils. The main mechanism generating the flow is the production of spatially chaotic path by changing the direction of flow using a 90° bend in helical coils (alternating Dean flow). If the direction of centrifugal force is rotated by any angle, the plane of vortex formation also rotates with the same angle. Thus in helical flow a 90° shift in the direction of centrifugal force cause a complete flow inversion. Complete flow fields and thermal fields in helical coil and bent coil configuration were studied using computational fluid dynamics software (FLUENT 6.0). The three-dimensional governing equations for momentum and energy under the laminar flow conditions were solved with a control-volume finite difference method (CVFDM) with second-order accuracy. The flow pattern obtained for the helical coil was in good agreement to those observed by the previous investigators [S.W. Jones, O.M. Thomas, H. Aref, Chaotic advection by laminar flow in twisted pipe. J. Fluid Mech. 209 (1989) 335-357; Ch. Duchene, H. Peerhossaini, P.J. Michard, On the velocity field and tracer patterns in a twisted duct flow. Phys. Fluids 7 (1995) 1307-1317]. The comparison of the flow fields and temperature fields in the helical tube and bent coil configuration are discussed. The bent coil configuration shows a 20-30% enhancement in the heat transfer due to chaotic mixing while relative pressure drop is 5-6%. The results of the present study can be used to model transport processes for developing flows in curved tubes such as chromatographic columns (less axial dispersion [A.K. Saxena, K.D.P. Nigam, Coiled configuration for flow inversion and its effect on residence time distribution. AIChE J. 30 (1984) 363-368]), Chemical reactors (narrower RTD), heat transfer devices, and some biomedical devices. © 2005 Elsevier Ltd. All rights reserved.
Citation: International Journal of Heat and Mass Transfer (2005), 48(23-24): 4811-4828
URI: https://doi.org/10.1016/j.ijheatmasstransfer.2005.05.037
http://repository.iitr.ac.in/handle/123456789/2862
Issue Date: 2005
Keywords: Bent coils
CFD
Heat transfer
Helical tube
ISSN: 179310
Author Scopus IDs: 7404634425
22980653700
Author Affiliations: Kumar, V., Department of Chemical Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016, India
Nigam, K.D.P., Department of Chemical Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016, India
Funding Details: The authors gratefully acknowledge the Ministry of Chemical and Fertilizers, GOI, India for funding the project.
Corresponding Author: Nigam, K.D.P.; Department of Chemical Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016, India; email: nigamkdp@gmail.com
Appears in Collections:Journal Publications [CH]

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