A Review of Airside Heat Transfer Augmentation with Vortex Generators on Heat Transfer Surface

Heat exchanger performance can be improved via the introduction of vortex generators to the airside surface, based on the mechanism that the generated longitudinal vortices can disrupt the boundary layer growth, increase the turbulence intensity and produce secondary fluid flows over the heat transf...

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Main Authors: Lei Chai, Savvas A. Tassou
Format: Article
Language:English
Published: MDPI AG 2018-10-01
Series:Energies
Subjects:
Online Access:http://www.mdpi.com/1996-1073/11/10/2737
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author Lei Chai
Savvas A. Tassou
author_facet Lei Chai
Savvas A. Tassou
author_sort Lei Chai
collection DOAJ
description Heat exchanger performance can be improved via the introduction of vortex generators to the airside surface, based on the mechanism that the generated longitudinal vortices can disrupt the boundary layer growth, increase the turbulence intensity and produce secondary fluid flows over the heat transfer surfaces. The key objective of this paper is to provide a critical overview of published works relevant to such heat transfer surfaces. Different types of vortex generator are presented, and key experimental techniques and numerical methodologies are summarized. Flow phenomena associated with vortex generators embedded, attached, punched or mounted on heat transfer surfaces are investigated, and the thermohydraulic performance (heat transfer and pressure drop) of four different heat exchangers (flat plate, finned circular-tube, finned flat-tube and finned oval-tube) with various vortex-generator geometries, is discussed for different operating conditions. Furthermore, the thermohydraulic performance of heat transfer surfaces with recently proposed vortex generators is outlined and suggestions on using vortex generators for airside heat transfer augmentation are presented. In general, the airside heat transfer surface performance can be substantially enhanced by vortex generators, but their impact can also be significantly influenced by many parameters, such as Reynolds number, tube geometry (shape, diameter, pitch, inline/staggered configuration), fin type (plane/wavy/composite, with or without punched holes), and vortex-generator geometry (shape, length, height, pitch, attack angle, aspect ratio, and configuration). The finned flat-tube and finned oval-tube heat exchangers with recently proposed vortex generators usually show better thermohydraulic performance than finned circular tube heat exchangers. Current heat exchanger optimization approaches are usually based on the thermohydraulic performance alone. However, to ensure quick returns on investment, heat exchangers with complex geometries and surface vortex generators, should be optimized using cost-based objective functions that consider the thermohydraulic performance alongside capital cost, running cost of the system as well as safety and compliance with relevant international standards for different applications.
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spelling doaj.art-b9143333c6cc47d5a7964537b52b91182022-12-22T02:56:26ZengMDPI AGEnergies1996-10732018-10-011110273710.3390/en11102737en11102737A Review of Airside Heat Transfer Augmentation with Vortex Generators on Heat Transfer SurfaceLei Chai0Savvas A. Tassou1RCUK Centre for Sustainable Energy Use in Food Chains (CSEF), Institute of Energy Futures, Brunel University London, Uxbridge, Middlesex UB8 3PH, UKRCUK Centre for Sustainable Energy Use in Food Chains (CSEF), Institute of Energy Futures, Brunel University London, Uxbridge, Middlesex UB8 3PH, UKHeat exchanger performance can be improved via the introduction of vortex generators to the airside surface, based on the mechanism that the generated longitudinal vortices can disrupt the boundary layer growth, increase the turbulence intensity and produce secondary fluid flows over the heat transfer surfaces. The key objective of this paper is to provide a critical overview of published works relevant to such heat transfer surfaces. Different types of vortex generator are presented, and key experimental techniques and numerical methodologies are summarized. Flow phenomena associated with vortex generators embedded, attached, punched or mounted on heat transfer surfaces are investigated, and the thermohydraulic performance (heat transfer and pressure drop) of four different heat exchangers (flat plate, finned circular-tube, finned flat-tube and finned oval-tube) with various vortex-generator geometries, is discussed for different operating conditions. Furthermore, the thermohydraulic performance of heat transfer surfaces with recently proposed vortex generators is outlined and suggestions on using vortex generators for airside heat transfer augmentation are presented. In general, the airside heat transfer surface performance can be substantially enhanced by vortex generators, but their impact can also be significantly influenced by many parameters, such as Reynolds number, tube geometry (shape, diameter, pitch, inline/staggered configuration), fin type (plane/wavy/composite, with or without punched holes), and vortex-generator geometry (shape, length, height, pitch, attack angle, aspect ratio, and configuration). The finned flat-tube and finned oval-tube heat exchangers with recently proposed vortex generators usually show better thermohydraulic performance than finned circular tube heat exchangers. Current heat exchanger optimization approaches are usually based on the thermohydraulic performance alone. However, to ensure quick returns on investment, heat exchangers with complex geometries and surface vortex generators, should be optimized using cost-based objective functions that consider the thermohydraulic performance alongside capital cost, running cost of the system as well as safety and compliance with relevant international standards for different applications.http://www.mdpi.com/1996-1073/11/10/2737heat transfer augmentationpressure-drop penaltyheat transfer surfacevortex generators
spellingShingle Lei Chai
Savvas A. Tassou
A Review of Airside Heat Transfer Augmentation with Vortex Generators on Heat Transfer Surface
Energies
heat transfer augmentation
pressure-drop penalty
heat transfer surface
vortex generators
title A Review of Airside Heat Transfer Augmentation with Vortex Generators on Heat Transfer Surface
title_full A Review of Airside Heat Transfer Augmentation with Vortex Generators on Heat Transfer Surface
title_fullStr A Review of Airside Heat Transfer Augmentation with Vortex Generators on Heat Transfer Surface
title_full_unstemmed A Review of Airside Heat Transfer Augmentation with Vortex Generators on Heat Transfer Surface
title_short A Review of Airside Heat Transfer Augmentation with Vortex Generators on Heat Transfer Surface
title_sort review of airside heat transfer augmentation with vortex generators on heat transfer surface
topic heat transfer augmentation
pressure-drop penalty
heat transfer surface
vortex generators
url http://www.mdpi.com/1996-1073/11/10/2737
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