PERFORMANCE-CHARACTERISTICS CORRELATION FOR ROUND TUBE AND PLATE FINNED HEAT-EXCHANGERS

A number of correlation equations describing the performance character istics of round tube and plate fin have been published in the open lit erature. However, many of these correlations are restricted to flat fi nned heat exchangers and a limited number of geometrical configuration s. In this study, 28 heat exchanger samples were tested in an open cir cuit thermal wind tunnel over a velocity range of 1 to 20 m/s for a nu mber of geometries. The,geometrical variations include the number of t ube rows, fin thickness and the spacing between fins, rows and tubes. Both flat and corrugated fins were tested and the results were correla ted in terms of j and f factors as a function of Reynolds number and t he geometrical parameters of the heat exchangers. An important feature of this correlation is the novel way in which the geometric parameter s are expressed in the correlation. Ratios of these parameters are der ived from consideration of the physics of the flow and heat transfer i n the heat exchangers, This results in a more accurate and physically meaningful correlation which can be applied to a broader range of geom etries, The correlation was validated against test data in the literat ure for round tube and plate fin with good agreement. It was found tha t the fin type affects the heat transfer and friction factor, and that the number of tube rows has a negligible effect on the friction facto r. The number of tube rows effect was found to be influenced by the fi n and tube geometries as well as the Reynolds number. (C) 1998 Elsevie r Science Ltd and IIR. All rights reserved.