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1

A new correlation for predicting the hydrothermal characteristics over flat tube banks

Sahel Djamel, Ameur Houari, Boudaoud Warda

Journal of Mechanical and Energy Engineering

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2019

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Vol. 3, No 3

273--280

EN

The flat tubes are necessary apparatus to design the modern heat exchangers. In this context, a CFD (computational fluid dynamics) study has been achieved to explore the influence of the flat tube size on the heat transfer characteristics in cross-flow over flat tube banks. The calculations are performed with the help of the computer software (Fluent) which is based on the finite volume method to solve the continuity, momentum and energy equations. The numerical investigations are achieved for laminar flow (Reynolds numbers changing from 50 to 800), two dimensional flows and incompressible fluids. Some predicted results are compared with available experimental data of the literature and a satisfactory agreement is observed. The obtained results show a decrease in the heat transfer coefficient with increased size of the flat tube. A new valuable empirical correlation is suggested for the prediction of heat transfer coefficients over a flat tube bank. The proposed correlation may be useful for engineers to predict the heat transfer rates in such devices without requirements of experimental measurements.

2

An application of electrochemical technique in analysis of heat distribution in a tube bank during gas-liqiud two-phase flow

Siejka K., Ulbrich R.

Turbulence : international journal

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2007

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Vol. 12

105-113

EN

Electrochemical technique was applied to analyze the heat distribution in a tube bank in a bubbling gas-liquid flow column reactor. Results of the research on distribution of heat transfer rate on the surface of horizontal oriented tube bundles with two-phase gas-liquid crosswise flow in shell side of heat exchangers were presented in the paper. Basing on the obtained results, authors recognize electrochemical technique as very useful and of a great potential. It's noteworthy since it provides for finding mean and local heat transfer coefficients that result from conditions in both hydraulic and thermal developing region. Moreover, this technique seems to be low cost one and is the most accurate of all indirect methods of determining heat transfer coefficient.

3

Intensyfikacja wymiany ciepła w kotłowych pęczkach konwekcyjnych

Pronobis M., Kalisz S., Wejkowski R.

Gospodarka Paliwami i Energią

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2002

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nr 12

21-24

PL

Przedstawiono rezultaty badań nowych sposobów intensyfikacji wnikania ciepła w kotłowych pęczkach konwekcyjnych. Dla zwiększenia burzliwości strugi w przestrzeniach międzypęczkowych zastosowano nowe rodzaje ożebrowań oraz odpowiednio zaprojektowane przewężenie kanału. Badania modelowe przeprowadzono wykorzystując metodę analogii naftalenowej. Ich wyniki porównane z rezultatami uzyskanymi dla klasycznych wymienników z rur gładkich potwierdziły zasadność stosowania intensyfikatorów.

EN

The paper presents the results of new investigations concerning heat transfer augmentation in convective tube banks. The heat and mass transfer analogy by means of naphthalene sublimation technique is used in order to evaluate heat transfer performance in diagonally shaped membrane heating surfaces, triple finned tube arrangements as well as in flue gas ducts equipped with narrowings. The effect of tube bank arrangement on heat transfer coefficients and flow resistance is discussed. Obtained results show significant improvement in comparison to those obtained for plain tube arrangements.