Airside performance of oval tube heat exchangers having sine wave fins under wet condition

Abstract

Experiments were conducted on sine wave fin-and-tube heat exchangers having oval tubes under wet condition. Twelve samples having different fin pitches (2.12 mm, 2.54 mm, 3.18 mm) and tube rows (one to four) were tested. Eight herringbone wave fin-and-tube heat exchangers having round tubes were also tested. Results showed that, for oval tube samples, the effect of fin pitch on j and f factor was not significant. As for the effect of tube row, the lowest j factor was obtained for one row configuration, which is clear contrast to round tube samples, where the highest j factor was obtained for one row configuration. Possible reasoning is provided considering the flow and heat transfer characteristics of sine wave channel combined with connecting oval tubes. Oval tube samples yielded superior airside performance than round tube samples when both heat transfer and pressure drop were considered. It is also shown that oval geometry is more beneficial under wet condition than under dry condition.