Investigation of heat transfer performance and enhancement mechanisms of supercritical carbon dioxide in PCHE with fractal airfoil fins

fractal structure featuring symmetric/asymmetric airfoil fins is embedded within the smooth channels of the printed circuit heat exchanger (PCHE), significantly enhancing its heat transfer performance. In this study, a horizontally installed two-layer channel configuration is examined, with hot CO 2 flowing through the upper channel and cold CO 2 through the lower channel. distinct airfoil fin designs, namely NACA 0021 symmetric and NACA 4822 asymmetric, are tested their channel reinforcement effect. The numerical analysis reveals that channels equipped with these fins exhibit substantially improved heat transfer compared to smooth channels. tably, the comprehensive evaluation index for the asymmetric airfoil fin channel is enhanced factor ranging from 1.05 to 3.76. Moreover, despite a modest increase in pressure drop, indicated a dimensionless friction factor of 0.67 - 1.31, the heat transfer performance remains superior. Crucially, optimal heat transfer does not rely solely on high fluid flow rates but instead demands apt flow matching between the hot and cold fluid channels.