Numerical Analysis of Slotted Airfoil Fins for Printed Circuit Heat Exchanger in S-CO2 Brayton Cycle

Abstract

Recuperator is one of the most important components in supercritical carbon dioxide (S-CO2) Brayton cycle, and the printed circuit heat exchanger (PCHE) has been considered as a promising candidate due to its high efficiency and compactness. The airfoil fin (AFF) PCHE has higher thermal-hydraulic performance than conventional zigzag channel PCHE. However, it also suffers from serious local flow resistance caused by the impact area. Two types of new slotted fins (SFs) based on AFFs including longitudinal slot fins (LSFs) and herringbone slot fins (HSFs) are proposed to release the effect of the impact area. The results show that both LSFs and HSFs can significantly reduce the flow resistance in the channel. Meanwhile, the SFs also show higher thermal performance due to the heat transfer area enhancement by the slots. The LSF channel can be considered as a promising candidate in some energy conversion systems due to its good hydraulic performance, while the HSF channel would behave more efficiently such as in refrigeration cycles due to its high thermal performance. Finally, the field synergy principle is employed to discuss the flow drag reduction in SF channels.