On the Heat Transfer Enhancement of Plate Fin Heat Exchanger

The plate fin heat exchanger is a compact heat exchanger applied in many industries because of its high thermal performance. To enhance the heat transfer of plate fin heat exchanger further, three new kinds of wavy plate fins, namely perforated wavy fin, staggered wavy fin and discontinuous wavy fin, are proposed and investigated by computational fluid dynamics (CFD) simulations. The effects of key design parameters, including that of waviness aspect ratios, perforation diameters, staggered ratios and breaking distance are investigated, respectively, with Reynolds number changes from 500 to 4500. It is found that due to the swirl flow and efficient mixing of the fluid, the proposed heat transfer enhancement techniques all have advantages over the traditional wavy fin. At the same time, serration is beneficial to reduce the friction factor, and the breaking technique can reduce heat transfer area. Through the performance evaluation criteria, the staggered wavy fin has an advantage over the small waviness aspect ratio; with increasing waviness aspect ratio, this predominance is gradually surpassed by the perforated wavy fin, and the advantage of the discontinuous fin is the smallest and almost invariable. A maximum performance evaluation criteria (PEC) as high as 1.24 can be obtained for the perforated wavy fin at the waviness aspect ratio = 0.45.