Experimental study and modelling of heat transfer during condensation of pure fluid and binary mixture on a bundle of horizontal finned tubes

Condensation heat transfer in a bundle of horizontal enhanced surface copper tubes (Gewa C+ tubes) has been experimentally investigated, and a comparison with trapezoidal shaped fin tubes with several fin spacing has been made. These tubes have a specific surface three-dimensional geometry (notched fins) and the fluids used are either pure refrigerant (HFC134a) or binary mixtures of refrigerants (HFC23/HFC134a). For the pure fluid and a Gewa C+ single tube, the results were analyzed with a specifically developed model, taking into account both gravity and surface tension effects. For the bundle and for a pure fluid, the inundation of the lowest tubes has a strong effect on the Gewa C+ tube performances contrary to the finned tubes. For the mixture, the heat transfer coefficient decreases dramatically for the Gewa C+ tube.

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Condensation heat transfer of a pure fluid and binary mixture outside a bundle of smooth horizontal tubes. Comparison of experimental results and a classical model

International Journal of Refrigeration ◽

10.1016/s0140-7007(00)00037-2 ◽

2001 ◽

Vol 24 (8) ◽

pp. 841-855 ◽

Cited By ~ 31

Author(s):

M. Belghazi ◽

A. Bontemps ◽

J.C. Signe ◽

C. Marvillet

Keyword(s):

Heat Transfer ◽

Binary Mixture ◽

Classical Model ◽

Experimental Results ◽

Condensation Heat Transfer ◽

Horizontal Tubes ◽

Pure Fluid

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Intensified Convection Heat Transfer of Single-Row Bunch of Finned Tubes in an Air Stream: Experimental Study and Generalization of the Obtained Data

ENERGETIKA Proceedings of CIS higher education institutions and power engineering associations ◽

10.21122/1029-7448-2018-61-6-552-563 ◽

2018 ◽

Vol 61 (6) ◽

pp. 552-563 ◽

Cited By ~ 1

Author(s):

A. B. Sukhotskii ◽

G. S. Маrshаlоvа

Keyword(s):

Heat Transfer ◽

Experimental Study ◽

Convection Heat Transfer ◽

Outer Diameter ◽

Design Calculation ◽

Single Row ◽

Method Of Calculation ◽

Finned Tubes ◽

Heated Air ◽

The One

The article presents method and results of experimental study of the intensified heat transfer for the single-row bunch consisting of bimetallic pipes with spiral knurled ribs with the following parameters: outer diameter of a rib d = 56 mm; rib height h = 15 mm, rib pitch s = 2.5 mm, average thickness of a rib D = 0.5 mm; diameter of a rib at the bottom d0 = 26 mm, coefficient of fins j = 21. The pipes cross pitch S1 in a single-row bunch makes 58, 61, 64 and 70 mm. The intensification of a heat transfer has been arranged in a stream of heated air over an experimental bunch by means of two types of exhaust shaft i.e. the one with adjustable height and the one with the adjustable section through passage. The aim of the work was to perform an experimental study and to summarize the data of a heat transfer of the single-row bunches consisting of bimetallic finned tubes under the intensified (mixed) air convection and also to develop an engineering method of calculation of single-row recirculation air heaters. The results of experimental study of the intensified convective heat transfer of the single-row bunch consisting of bimetallic finned tubes in a stream of heated air are presented in the form of dependences of number of Nusselt on Grashof number and Reynolds number. As a result of generalization of experimental data, the generalized criteria equation for calculation of heat transfer of the single-row bunch consisting of bimetallic finned tubes when cross pitches of installation of tubes, the areas of exhaust outlets and heights of the exhaust shaft are various, has been obtained. The engineering technique for design calculation of the single-row recirculation air heater has also been developed.

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