Heat Transfer in Cross-Flow Heat Exchangers and Packed Beds

Abstract An experimental study on the air-side heat transfer and pressure drop characteristics for multi-louvered fin and flat tube heat exchangers has been performed. For 45 heat exchangers with different louver angles (15–29°), fin pitches (1.0, 1.2, 1.4 mm) and flow depths (16, 20, 24 mm), a series of tests were conducted for the air-side Reynolds numbers of 100–600, at a constant tube-side water flow rate of 0.32 m3/h. The inlet temperatures of the air and water for heat exchangers were 21°C and 45°C, respectively. The air-side thermal performance data were analyzed using effectiveness-NTU method for cross-flow heat exchanger with both fluids unmixed. The heat transfer coefficient and pressure drop data for heat exchangers with different geometrical configurations were reported in terms of Colburn j-factor and Fanning friction factor f, as functions of Reynolds number based on louver pitch. Correlations for j and f factors are developed and compared to other correlations.

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Heat transfer enhancement in cross-flow heat exchangers using oval tubes and multiple delta winglets

International Journal of Heat and Mass Transfer ◽

10.1016/s0017-9310(03)00047-4 ◽

2003 ◽

Vol 46 (15) ◽

pp. 2841-2856 ◽

Cited By ~ 70

Author(s):

S. Tiwari ◽

D. Maurya ◽

G. Biswas ◽

V. Eswaran

Keyword(s):

Heat Transfer ◽

Heat Transfer Enhancement ◽

Heat Exchangers ◽

Cross Flow ◽

Transfer Enhancement ◽

Flow Heat

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Parametric study of heat transfer enhancement on cross-flow heat exchangers

Chemical Engineering and Processing - Process Intensification ◽

10.1016/j.cep.2017.07.014 ◽

2017 ◽

Vol 121 ◽

pp. 81-89 ◽

Cited By ~ 3

Author(s):

X.J. Luo

Keyword(s):

Heat Transfer ◽

Heat Transfer Enhancement ◽

Parametric Study ◽

Heat Exchangers ◽

Cross Flow ◽

Transfer Enhancement ◽

Flow Heat

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Iteration-free calculation of the heat transfer coefficient in air-cooled cross-flow heat exchangers

The Chemical Engineering Journal ◽

10.1016/0300-9467(74)80028-6 ◽

1974 ◽

Vol 7 (1) ◽

pp. 79-81 ◽

Cited By ~ 4

Author(s):

Wilfried Roetzel

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Heat Exchangers ◽

Cross Flow ◽

Flow Heat ◽

The Heat Transfer Coefficient

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Evaluation of selected methods of the heat transfer coefficient determination in fin-and-tube cross-flow heat exchangers

MATEC Web of Conferences ◽

10.1051/matecconf/201824002004 ◽

2018 ◽

Vol 240 ◽

pp. 02004 ◽

Cited By ~ 1

Author(s):

Tomasz Bury ◽

Małgorzata Hanuszkiewicz Drapała

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Heat Exchanger ◽

Transfer Coefficient ◽

Heat Exchangers ◽

Cross Flow ◽

Transfer Coefficients ◽

Heat Transfer Coefficients ◽

Flow Heat ◽

The Heat Transfer Coefficient

The work is a part of a thermodynamic analysis of a finned cross-flow heat exchanger of the liquid-gas type. The heat transfer coefficients on the liquid and the gas side and the area of the heat transfer are the main parameters describing such a device. The basic problem in computations of such heat exchangers is determination of the coefficient of the heat transfer from the finned surfaces to the gas. The differences in the heat transfer coefficient local values resulting from the non-uniform flow of mediums through the exchanger complicates the analysis additionally. Six Nusselt number relationships are selected as suitable for the considered heat exchanger, and they are used to calculate the heat transfer coefficient for the air temperature ranging from 10°C to 30°C and for the velocity values ranging from 2 m/s to 20 m/s. In the next step, the gas-side heat transfer coefficient is determined by means of numerical simulations using a numerical model of a repetitive fragment of the heat exchanger under consideration. Finally, the Wilson plot method is also used. The work focuses on an analysis of the in-house HEWES code sensitivity to the method of the heat transfer coefficient determination. The authors believe that the analysis may also be useful for the evaluation of different methods of the heat transfer coefficient computation.

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