Heat Transfer and Friction Characteristics of Printed Circuit Heat Exchangers with Different Channel Structures for S-CO₂ Power System

Printed circuit heat exchanger (PCHE) has been widely used in supercritical carbon dioxide (S-CO₂) power systems because of its high heat transfer efficiency and good compactness. However, due to the large variety of PCHE configurations, channel selection in practical applications lacks a basis. Therefore, this paper discussed the heat transfer and friction characteristics and the synergy of three fields in the channel under the guidance of the field synergy principle for four typical PCHE channels. Additionally, the comprehensive performance of four channels was compared. Finally, the heat transfer and friction factor correlations for S-CO₂ in four channels were established. The findings demonstrate that the synergy of velocity and pressure fields of the straight channel PCHE is better (β≈180°), so its resistance loss is relatively small. The zigzag and sinusoidal wavy channels and the airfoil fins can reduce the angle α between the temperature gradient and velocity, thus enhancing the heat transfer. The sinusoidal wavy channel can reduce flow resistance compared to the zigzag channel due to the rounded corners. The streamlined airfoil structure can guide the flow and reduce backflow, thus reducing resistance losses. In the range of Re studied in this paper, the maximum error of the proposed heat transfer and friction factor correlations of PCHE is 7.0%, which shows good fitting accuracy. The research in this paper can provide a reference for the selection and design of PCHE with different channel configurations.