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Numerical analysis of heat transfer enhancement in a double pipe heat exchanger with porous fins

Numerical analysis of heat transfer enhancement in a double pipe heat exchanger with porous fins Purpose – The aim is to study numerically the heat transfer enhancement in a double pipe heat exchanger by using porous fins attached at the external wall of the inner cylinder. Design/methodology/approach – The Brinkman‐Forchheimer extended Darcy model is used in the porous regions. The differential equations subjected to the boundary conditions are solved numerically using the finite volume method. Numerical calculations are performed for a wide range of Darcy number (10 −6 ≤ Da ≤10 −1 ), porous fins height (0≤ H p ≤1) and spacing (0≤ L f ≤39) and thermal conductivity ratio (1≤ R k ≤100). The effects of these parameters are considered in order to look for the most appropriate properties of the porous fins that allow optimal heat transfer enhancement. Findings – The results obtained show that the insertion of porous fins may alter substantially the flow pattern depending on their permeability, height and spacing. Concerning the heat transfer effect, it is found that the use of porous fins may enhance the heat transfer in comparison to the fluid case and that the rate of improvement depends on their geometrical and thermo‐physical properties. Performance analysis indicated that more net energy gain may be achieved as the thermal conductivity ratio increases especially at high Darcy numbers and heights. Research limitations/implications – The results obtained in this work are valid for double pipe heat exchangers with the same fluid flowing at the same flow rate in the two ducts and for the case of an inner cylinder of negligible thermal resistance. Practical implications – The results obtained in this study can be used in the design of heat exchangers. Originality/value – This study provides an interesting method to improve heat transfer in a double pipe heat exchanger by use of porous fins. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png International Journal of Numerical Methods for Heat and Fluid Flow Emerald Publishing

Numerical analysis of heat transfer enhancement in a double pipe heat exchanger with porous fins

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References (14)

Publisher
Emerald Publishing
Copyright
Copyright © 2008 Emerald Group Publishing Limited. All rights reserved.
ISSN
0961-5539
DOI
10.1108/09615530810879738
Publisher site
See Article on Publisher Site

Abstract

Purpose – The aim is to study numerically the heat transfer enhancement in a double pipe heat exchanger by using porous fins attached at the external wall of the inner cylinder. Design/methodology/approach – The Brinkman‐Forchheimer extended Darcy model is used in the porous regions. The differential equations subjected to the boundary conditions are solved numerically using the finite volume method. Numerical calculations are performed for a wide range of Darcy number (10 −6 ≤ Da ≤10 −1 ), porous fins height (0≤ H p ≤1) and spacing (0≤ L f ≤39) and thermal conductivity ratio (1≤ R k ≤100). The effects of these parameters are considered in order to look for the most appropriate properties of the porous fins that allow optimal heat transfer enhancement. Findings – The results obtained show that the insertion of porous fins may alter substantially the flow pattern depending on their permeability, height and spacing. Concerning the heat transfer effect, it is found that the use of porous fins may enhance the heat transfer in comparison to the fluid case and that the rate of improvement depends on their geometrical and thermo‐physical properties. Performance analysis indicated that more net energy gain may be achieved as the thermal conductivity ratio increases especially at high Darcy numbers and heights. Research limitations/implications – The results obtained in this work are valid for double pipe heat exchangers with the same fluid flowing at the same flow rate in the two ducts and for the case of an inner cylinder of negligible thermal resistance. Practical implications – The results obtained in this study can be used in the design of heat exchangers. Originality/value – This study provides an interesting method to improve heat transfer in a double pipe heat exchanger by use of porous fins.

Journal

International Journal of Numerical Methods for Heat and Fluid Flow – Emerald Publishing

Published: Jun 27, 2008

Keywords: Heat exchangers; Liquid flow; Heat transfer; Numerical analysis

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