Effect of Novel Stepped Airfoil Fin Inserts on Heat Transfer Enhancement and Fluid Flow Characteristics of Printed Circuit Heat Exchanger

In recent years, researchers have shown considerable interest in supercritical carbon dioxide (sCO₂) Brayton cycle-based power plants due to their unique characteristics and higher efficiency compared with conventional Rankine cycle systems. The printed circuit heat exchanger (PCHE) is a key component that significantly influences the performance of the sCO₂ cycle, owing to its compact structure and high surface area-to-volume ratio. However, designing efficient and compact PCHEs continues to be a significant challenge, mainly because it requires balancing heat transfer effectiveness with pressure drop, a task made more complex by the intricate configuration of micro-channels. This study aims to investigate the impact of airfoil fin geometry modifications on heat transfer enhancement in PCHEs using the ANSYS Fluent computational tool. Ten novel stepped airfoil fin models were introduced and analysed. The results demonstrate that airfoil fin model 9, characterised by a double-stepped profile and a flattened trailing edge, achieves a 28% increase in heat transfer rate and a 27.37% improvement in the Nusselt number compared with the baseline airfoil fin design under various operating conditions. These improvements are attributed to enhanced turbulence generated by the stepped profile, which promotes more effective convective heat transfer.