Thermo-Hydraulic Performance of Printed Circuit Heat Exchanger With Different Cambered Airfoil Fins

This paper presents the thermo-hydraulic performance of printed circuit heat exchangers (PCHEs) with cambered NACA four-digit airfoil fins (AFFs) used as the condenser in supercritical CO₂ Brayton power cycle. Results show that the NACA8515 AFFs with consistent and reverse layout applied to a PCHE may averagely improve the transferred heat per unit area by 28% and 11% accompanying with increase of the pressure loss by 150% and 22%, respectively, compared to the PCHE with symmetrical AFFs. Based on the flow streamlines, the reverse and tangent fin layout with angled inlet manifold is proposed which can improve the overall performance effectively. The AFFs with cambers of 8.0%, 14.4%, 25.0% and 43.3% used in PCHEs are studied, and the Nusselt number can be averagely improved by 42%, 54%, 75% and 66%, besides the Darcy friction factor averagely increases 125%, 460%, 980% and 890%, respectively. Meanwhile, the overall performance has a maximum improvement of 39% at lower Reynolds number. In order to demonstrate the advantage of cambered AFFs more effectively, the PCHE with non-uniform layout of AFFs is proposed, and the overall performance of a typical case can be improved by 46% maximally and 25% averagely in the applicable range.