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ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
NUSSELT NUMBER EXPERIMENTAL CORRELATION FOR FORCED CONVECTION IN FINNED ASTM TUBES
Submission Author:
Rodrigo Ducatti Marson , SP
Co-Authors:
Rodrigo Ducatti Marson, José Alexandre Matelli, Alex Bimbato
Presenter: Rodrigo Ducatti Marson
doi://10.26678/ABCM.ENCIT2020.CIT20-0088
Abstract
The forced convection heat transfer on extended surfaces is largely applied in heat exchangers. These exchange surfaces have geometries dimensioned to promote controlled heat exchange between two or more fluids. Tubes with finned surfaces are recommended in heat exchangers that involve gaseous external flows. To design the surfaces of thermal exchanges, correlations are used to obtain the Nusselt number and thus calculate the coefficient of convective heat transfer. Classic correlations found in the heat transfer textbooks cover only plain tubes and simple surfaces, while the heat exchangers literature presents experimental values available to a very limited and standardized class of diameters, fins and pitch of tubes. The objective of this work is to experimentally determine the forced convection heat transfer for finned tube samples in different situations and, based on these results, to propose a specific experimental correlation for the air flow variation applicable in this type of finned tube. Samples of finned tubes are tested in a wind tunnel available. The correlation obtained from the experimental results provides consistent values. In the particular case of plain tubes, results from the correlation are significantly in accordance with the results obtained from the classical Zukauskas correlation, as shown by Pearson's chi-square test.
Keywords
forced convection, Heat exchanger, finned pipes, ASTM tube, experimental correlation, Wind Tunnel
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