AN EXPERIMENTAL INVESTIGATION OF THE AIR-SIDE PERFORMANCE OF FIN-AND-TUBE HEAT EXCHANGERS HAVING SLIT FINS

In this study, the heat transfer and friction characteristics of 5.3-mm outer-diameter slit-fin heat exchangers were experimentally investigated. Plain-fin heat exchangers having the same 5.3-mm outer-diameter tubes were also tested for comparison. Results revealed that slit-fin samples yielded higher j and f factors than plain-fin samples. As for the effect of number of tube rows, the j factor increased as the number of tube rows decreased, but the f factor was independent of this effect (except in the one-row configuration). The one-row samples yielded significantly higher f factors, especially at low Reynolds numbers. The j/f ratios for the slit fin samples were larger than those for the plain-fin samples at high Reynolds numbers. At low Reynolds numbers, in contrast, they were smaller. A new correlation was developed based on the present data.