Study of Heat and Mass Transfer in a Vertical-Tube Evaporative Cooler

1984 ◽  
Vol 106 (1) ◽  
pp. 210-215 ◽  
Author(s):  
H. Perez-Blanco ◽  
W. A. Bird
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Vertical Tube ◽  
Heat Fluxes ◽  
Transfer Coefficients ◽  
One Dimensional ◽  
Mass Transfer Processes ◽  
Air Water Interface ◽  
Evaporative Cooler ◽  
Interface Heat

Evaporative coolers are three-fluid heat exchangers used to reject heat to the environment. A mixture of air and recirculating water is used as the cooling medium. In this paper, the heat and mass transfer processes taking place in a vertical-tube evaporative cooler are studied. A steady-state, one-dimensional model of cooler performance is formulated and is validated by experimental measurements, taken in a single-tube exchanger, of the controlling heat and mass transfer coefficients. These coefficients occur at the air-water interface. Heat fluxes and enhancement ratios for conditions of interest are measured and calculated, and the results are compared and discussed. The model is found to adequately predict heat exchanger performance.

Enhancement of Combined Heat and Mass Transfer in a Vertical-Tube Heat and Mass Exchanger

1986 ◽  
Vol 108 (1) ◽  
pp. 70-75 ◽  
Author(s):  
R. L. Webb ◽  
H. Perez-Blanco
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Mass Transfer ◽  
Water Film ◽  
Vertical Tube ◽  
Transfer Coefficients ◽  
Interface Heat Transfer ◽  
Friction Performance ◽  
Predicted Values

This paper studies enhancement of heat and mass transfer between a countercurrent, gravity-drained water film and air flowing in a vertical tube. The enhancement technique employed is spaced, transverse wires placed in the air boundary layer, near the air-water interface. Heat transfer correlations for turbulent, single-phase heat transfer in pipes having wall-attached spaced ribs are used to select the preferred wire diameter, and to predict the gas phase heat and mass transfer coefficients. Tests were run with two different radial placements of the rib roughness: (1) at the free surface of the liquid film, and (2) the base of the roughness displaced 0.51 mm into the air flow. The authors hypothesize that the best heat/mass transfer and friction performance will be obtained with the roughness at the surface of the water film. Experiments conducted with both roughness placements show that the authors’ hypothesis is correct. The measured heat/mass transfer enhancement agreed very closely with the predicted values. A unique feature of the enhancement concept is that it does not require surface wetting of the enhancement device to provide enhancement.

Digital Computation Methods for Evaluating Heat Flux in Condensers

1965 ◽  
Vol 7 (2) ◽  
pp. 177-184 ◽  
Author(s):  
D. Chisholm ◽  
T. F. Provan ◽  
D. Mitchell
Keyword(s):  
Mass Transfer ◽  
Heat Flux ◽  
Numerical Methods ◽  
Heat And Mass Transfer ◽  
Digital Computer ◽  
Local Heat ◽  
Heat Fluxes ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Digital Computation

Numerical methods of evaluating heat- and mass-transfer coefficients and local heat fluxes in surface condensers are outlined using the correlations for the vapour-side coefficients of Berman and Fuks, Chilton and Colburn, and Akers, Davis and Crawford. The procedures are particularly appropriate where a digital computer is used in solving the equations.

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