An experimental study of the air-side performance of fin-and-tube heat exchangers having plain, louver, and semi-dimple vortex generator configuration

Wang, Chi-Chuan; Chen, Kuan‐Yu; Liaw, Jane Sunn; Tseng, Chyuan-Yow

doi:10.1016/j.ijheatmasstransfer.2014.09.030

Cited by 78 publications

(23 citation statements)

References 32 publications

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“…), while the fin material and fin thickness had insignificant effects on the JF factor. Wang et al [57] made a comparative study of the airside performance of fin-tube heat exchangers respectively with plain, louvre and semi-dimple VGs. They tested the fin pitch between 1.6 mm and 2.0 mm and the number of tube rows of 1, 2 and 4.…”

Section: Effect Of Geometry Parametersmentioning

confidence: 99%

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

Chai

Tassou

2018

Energies

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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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Section: Effect Of Geometry Parametersmentioning

confidence: 99%

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

Chai

Tassou

2018

Energies

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“…The LVG is a secondary flow augmentation that can provide certain heat transfer augmentation without significant pressure drop penalty. In fact, a recent study by Wang et al [34] had mentioned that the semi-dimple LVG can be more effective than the louver fin geometry for fin-and-tube heat exchanger with fewer number of tube row. For electronic cooling using LVG, Yang et al [35,36] had experimentally examined various types of vortex generator, such as delta wing, triangular winglet, semi-circular, and dimples having loose and dense density.…”

Section: Heat Transfer Augmentation Via Fin Configurationmentioning

confidence: 99%

A Quick Overview of Compact Air-Cooled Heat Sinks Applicable for Electronic Cooling—Recent Progress

Wang

2017

Inventions

Self Cite

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Abstract:This study provides an overview regarding enhancement of an air-cooled heat sink applicable for electronic cooling subject to cross-flow forced convection. Some novel designs and associated problems in air-cooled heat sinks are discussed, including the drawback of adding surfaces, utilization of porous surfaces such as metal foam or carbon foam, problems and suitable applicable range of highly interrupted surfaces (louver or slit) and longitudinal vortex generator. Though the metal foam may accommodate significant surface area, it is comparatively ineffective for air-cooling application due to its much lower fin efficiency, and this shortcoming can be improved by integrating with solid fin. For highly dense fin spacing (e.g., <1.0 mm), cannelure or grooved surface may be a better choice, and fin structure with periodic contraction and expansion may not be suitable for it introduces additional pressure drop penalty. The partial bypass concept, which manipulates a larger temperature difference at the trailing part of heat sink, can be implemented to significantly reduce the pressure drop. Through some certain niche operation, t the thermal resistance of the partial bypass heat sink may be superior to the conventional heat sink. The trapezoid fin surface featuring easier manufacturing and a smaller weight is shown to have competitive performance against traditional rectangular fin geometry. The IPFM (Interleaved Parallelogram Fin Module) design which combines two different geometrical fins with the odd number fins being rectangular shape, and parallelogram shape in even fin numbers, shows 8%-12% less surface than conventional design but still offers a lower thermal resistance than the conventional rectangular heat sink in lower flowrate operation. The cross-cut design shows appreciable improvements as compared to the conventional plate fin design especially in high velocity regime and the single cross-cut heat sinks are superior to multiple cross-cut heat sinks.

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“…Li et al (2014) studied the heat transfer performance by varying fin pitch and winglet length of a fin-and-tube heat exchanger for radiantly arranged delta winglets over different tubes with staggered arrangement. Wang et al (2015a) performed experiments and compared the performance of plain fin model and semi dimple VGs for different fin pitch and tube row number. They conducted further experiments to compare the semi dimple configuration with louver and plain fin configuration (Wang et al, 2015b).…”

Section: Introductionmentioning

confidence: 99%

Parametric Investigation of Wavy Rectangular Winglets for Heat Transfer Enhancement in a Fin-and–Tube Heat Transfer Surface

Sarangi¹,

Mishra²,

Mishra³

2020

JAFM

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In this paper numerical simulations were performed utilizing Computational fluid dynamics code Fluent to investigate the thermo-fluid performance of a wavy rectangular winglet supported fin-and-tube heat exchanger with five inline rows of circular tubes. The influence of wave height, number of waves, wavy winglet length and winglet attack angle on the thermo-fluid performance of the fin-and-tube heat transfer surface has been examined under laminar flow conditions. Further the Plain and wavy rectangular winglets are placed together over different tube locations and their effect on heat transfer and flow resistance is also examined. An enhancement factor has also been discussed to summarize the overall thermo-fluid performance. The results show that increase in the wave height increase both heat transfer and pressure drop, and an optimum wave height could be decided based on the enhancement factor. It is also found that the increase in wavy winglet length guides the flow more effectively towards the tubes wake region. It is also observed that with increase in number of waves the heat transfer performance initially increases and then decreases as the wave pitch becomes very small. For wavy winglet supported heat exchanger the optimum attack angle is found out for maximum enhancement factor.

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An experimental study of the air-side performance of fin-and-tube heat exchangers having plain, louver, and semi-dimple vortex generator configuration

Cited by 78 publications

References 32 publications

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

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

A Quick Overview of Compact Air-Cooled Heat Sinks Applicable for Electronic Cooling—Recent Progress

Parametric Investigation of Wavy Rectangular Winglets for Heat Transfer Enhancement in a Fin-and–Tube Heat Transfer Surface

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