Investigation of Design Models for Printed Circuit Heat Exchangers With Straight Semicircular Channels

Printed circuit heat exchangers (PCHEs) are a promising technology for the closed Brayton cycle of nuclear energy due to their high compactness, capability to withstand high pressure and large temperature difference, and high heat transfer efficiency. The design calculation of PCHEs has a significant impact on the cycle performance. This paper proposes a theoretical model for predicting the thermal-hydraulic performance of semicircular straight-channel PCHEs. The irregular fins are equivalent to rectangular fins of equal height, making the model more simplified and accurate. The model is verified using experimental data from the literature. Based on this model, the heat transfer characteristics of composite PCHEs, where crossflow exists at the inlet and outlet, are investigated. The results indicate that the heat transfer performance of PCHEs can be more accurately predicted by using the length of the overlapping region of hot and cold channels as the reference length. Furthermore, the effects of geometric parameters on the heat transfer performance of semicircular straight-channel PCHEs are studied. The results show that the heat transfer performance of the semicircular straight-channel PCHEs decreases with the increase of the channel radius and the vertical interval, and increases with the increase of the horizontal interval. And the horizontal and vertical interval affect heat transfer performance slightly. This study provides a reference for the design and application of PCHEs in the helium closed Brayton cycle in the future.