Effect of fin thickness on air-side performance of herringbone wavy fin-and-tube heat exchangers

Abstract

In the present study, the effects of fin thickness on the heat transfer and friction characteristics of fin-and-tube heat exchangers having herringbone wavy fin configuration are experimentally investigated. The experimental apparatus consists essentially of a well insulated open wind tunnel and herringbone wavy fin-and-tube heat exchangers made from aluminium plate finned, copper tube. Air and water are used to be working fluids in air-side and tube-side, respectively. A total of 10 samples of the fin-and-tube heat exchangers are tested. The experimental procedures are conducted by keeping the inlet water temperature at a pre-selected value, adjusting the water volumetric flow rate at a specific value and varying the air velocity. The results are presented as plots of the Colburn factor and friction factor against the Reynolds number based on the fin collar outside diameter (ReDc). From the results, it is found that for number of tube rows (N) = 2, the Colburn factor increases with increasing fin thickness. For N ≥ 4, the Colburn factor decreases with increasing fin thickness when ReDc 2500. The friction factor increases with increasing fin thickness when fin pitch (Fp) ≤ 1.81 mm.