Numerical study of fin-spacing effects in annular-finned tube heat exchangers

Mon, Mi Sandar; Groß, Ulrich

doi:10.1016/j.ijheatmasstransfer.2003.09.034

Cited by 177 publications

(88 citation statements)

References 12 publications

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“…Mon and Gross [14] investigated the effects of the fin spacing on four-row round-finned tube bundles in staggered and in-line arrangements by three dimensional numerical study.…”

Section: Literature Reviewmentioning

confidence: 99%

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Development of a new type of finned heat exchanger

Bošnjaković

Čikić²,

Muhič

et al. 2017

Teh. vjesn.

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Original scientific paper A new geometric form of fins (needle fins) for finned heat exchangers of gas-liquid type is described. It achieves a higher heat transfer coefficient and lower mass of the heat exchange surface relative to the heat exchangers with circular fins which in this case served as a basis for comparison. For the analysis of the heat transfer, the computational fluid dynamics analysis with ANSYS Fluent software was applied. Numerical simulation was performed for the round fins and fins with a new, innovative geometric shape at air flow speeds of 1 m/s to 5 m/s. The results of numerical simulations, with regard to the exchanged heat and pressure drop were verified by the correlations available in the literature and compared to the simulation results for tubes with innovative fins. Results show an increase in the amount of Nu from 20 % to 30 % for 2300 >Re > 12000 while reducing mass of heat exchange surfaces of 23,8 %.Keywords: finned heat exchanger; heat exchange; heat exchanger efficiency; needle fins; numerical simulation Razvoj novog tipa lamelnog izmjenjivača toplineIzvorni znanstveni članak Opisan je novi geometrijski oblik lamele (igličaste lamele) za orebrene cijevne izmjenjivače topline plin -tekućina pomoću kojeg se postiže veći koeficijent prijelaza topline, a time i manja masa izmjenjivačkih površina u odnosu na izmjenjivače topline s okruglim lamelama koji su u ovom slučaju poslužili kao baza za usporedbu. Za analizu izmjene topline i pada tlaka primijenjena je računalna dinamika fluida s programom ANSYS Fluent. Numerička simulacija provedena je za slučaj zagrijavanja zraka koji struji oko cijevi s lamelama novog geometrijskog oblika te oko cijevi s lamelama konvencionalnog kružnog oblika brzinama od 1 m/s do 5 m/s. Rezultati numeričke simulacije obzirom na izmijenjenu toplinu i pad tlaka za cijevi s okruglim lamelama provjereni su pomoću korelacija dostupnih u literaturi te su uspoređeni s rezultatima simulacije za cijevi s inovativnim lamelama. Rezultati pokazuju povećanje iznosa Nu značajke od 20 % do 30 % za 2300 > Re > 12000 uz smanjenje mase izmjenjivačkih površina od 23,8 %.

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“…Mon and Gross [14] investigated the effects of the fin spacing on four-row round-finned tube bundles in staggered and in-line arrangements by three dimensional numerical study.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Initial diameter, thickness and pitch of the fins were selected according to the recommendations of the authors dealing with the problem of finned tubular heat exchangers [4,12,13,14,22,28,29,30,31].…”

Section: Physical Model Of Heat Exchanger With Needle-shaped Finsmentioning

confidence: 99%

Development of a new type of finned heat exchanger

Bošnjaković

Čikić²,

Muhič

et al. 2017

Teh. vjesn.

View full text Add to dashboard Cite

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“…Tubes can be individually finned (e.g. plain circular fins and helical fins [1][2][3]) or multiple tubes can pass through each fin. For the latter, which result in a higher compactness, Wang et al [4] distinguished three generations of fin patterns.…”

Section: Introductionmentioning

confidence: 99%

“…Research on annular finned tubes and plain fin heat exchangers has shown that the fin pitch has a strong impact on the development of horseshoe vortices and thus on the local heat transfer coefficients [2,[13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Mon and Gross [2] numerically investigated the flow field and thermal hydraulic behaviour in a four row annular finned tube bundle. They found that the horseshoe vortex system is weak at low Reynolds numbers and for small fin spacings, while it becomes substantial for higher Reynolds numbers and a large fin spacing, resulting in an increased mean heat transfer coefficient.…”

Section: Introductionmentioning

confidence: 99%

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Study of junction flows in louvered fin round tube heat exchangers using the dye injection technique

Huisseune

T’Joen

Jaeger

et al. 2010

Experimental Thermal and Fluid Science

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Detailed studies of junction flows in heat exchangers with an interrupted fin design are rare. However, understanding these flow structures is important for design and optimization purposes, because the thermal hydraulic performance of heat exchangers is strongly related to the flow behaviour. In this study flow visualization experiments were performed in six scaled-up models of a louver fin round tube heat exchanger. The models have three tube rows in a staggered layout and differ only in their fin spacing and louver angle. A water tunnel was designed and built and the flow visualizations were carried out using dye injection. At low Reynolds numbers the streakline follows the tube contours, while at higher Reynolds numbers a horseshoe vortex is developed ahead of the tubes. The two resulting streamwise vortex legs are destroyed by the downstream louvers (i.e. downstream the turnaround louver), especially at higher Reynolds numbers, smaller fin pitches and larger louver angles. Increasing the fin spacing results in a larger and stronger horseshoe vortex. This illustrates that a reduction of the fin spacing results in a dissipation of vortical motion by mechanical blockage and skin friction. Furthermore it was observed that the vortex strength and number of vortices in the second tube row is larger than in the first tube row. This is due to the thicker boundary layer in the second tube row, and the flow deflection, which is typical for louvered fin heat exchangers. Visualizations at the tube-louver junction showed that in the transition part between the angled louver and the flat landing a vortex is present underneath the louver surface which propagates towards the angled louver.

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Heat transfer enhancement in annular fins using functionally graded material

Hassanzadeh

Pekel

2013

Heat Trans. Asian Res.

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This study presents a new approach on the heat transfer enhancement of annular fins with constant thickness using functionally graded materials. The thermal conductivity of the annular fin is assumed to be graded along the fin radius as a power‐law function. The resulting fin equation is solved by an approximate analytical method using the mean value theorem. The variable coefficients of second and third terms in the second‐order differential equation of the fin are replaced with their mean values along the fin radius. Several different graphs regarding the computed temperature profile, fin tip temperature, and fin efficiency are plotted with respect to the radii ratio thermo‐geometric parameter, and inhomogeneity parameter. It is demonstrated that the inhomogeneity parameter plays an important role on the heat transfer enhancement of the annular fin. However, for large radii ratios the effect of the inhomogeneity parameter decreases. Finally, it is stated that application of the functionally graded material in the annular fins, enhances the heat transfer rate between the fin and surrounding fluid resulting from the higher fin efficiency in comparison to the homogeneous annular fin. It is hoped that the results obtained from this study arouse interest among thermal designers and heat exchanger industries. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 42(7): 603–617, 2013; Published online in Wiley Online Library (http://wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21053

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Numerical study of fin-spacing effects in annular-finned tube heat exchangers

Cited by 177 publications

References 12 publications

Development of a new type of finned heat exchanger

Development of a new type of finned heat exchanger

Study of junction flows in louvered fin round tube heat exchangers using the dye injection technique

Heat transfer enhancement in annular fins using functionally graded material

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