Owing to their remarkable compactness and outstanding thermal efficiency, printed circuit heat exchangers (PCHEs) represent a highly viable candidate for systems coupling molten salt with supercritical carbon dioxide S-CO 2 . Investigating the geometric configuration and thermal-hydraulic behavior of such PCHEs is essential to further optimize their operating efficiency and structural density. This study proposes a new hybrid PCHE architecture that integrates zigzag continuous passages on the molten salt side with discontinuous airfoil-fin channels on the S-CO 2 side. A numerical framework, thoroughly verified against standard benchmark cases, was deployed to investigate the thermal and fluid dynamic characteristics of this new design. Across a range of operating scenarios, the variant featuring zigzag channels achieved a 2.89% to 13.9% enhancement in heat transfer effectiveness ( ε ) over the conventional straight-channel counterpart, albeit at the cost of a 36.5% to 40.5% rise in frictional pressure drops. Moreover, optimization of zigzag geometry in terms of pitch length, characteristic angle, and channel radius identified thermally optimal structures based on PEC, ε , and other indicators. Furthermore, flow–thermal coupling analysis revealed oscillatory temperature variations with phase-shifted peaks caused by structural disturbances and property contrasts. Meanwhile, slight inlet temperature increases on both molten salt and S-CO 2 sides improved overall performance. Finally, an empirical Nusselt number correlation for molten salt was proposed, with a deviation within ±1.2%.
Wang et al. (Mon,) studied this question.