Flow and heat transfer in compact offset strip fin surfaces

Experimental studies of air-side heat transfer and pressure drop characteristics of offset strip fins and flat tube heat exchangers were performed. A series of tests were conducted for 9 heat exchangers with different fin space, fin height, fin strip length and flow length, at a constant tube-side water flow rate of 2.5 m3/h. The characteristics of the heat transfer and pressure drop of different fin space, fin height and fin length were analyzed and compared. The curves of the heat transfer coefficients vs. the pumping power per unit frontal area were then plotted. Moreover, the enhanced heat transfer mechanism of offset strip fins was analyzed using field synergy theory. The results showed that fin length and flow length have more obviously effect on the thermal hydraulic characteristics of offset strip fins. © 2008 Higher Education Press and Springer-Verlag GmbH.