Numerical Study on Thermal-Hydraulic Characteristic and Performance of 3-D Printed Circuit Heat Exchanger Channel having Swirling Flow

Abstract

The supercritical carbon dioxide (sCO₂) Brayton cycle is a promising power conversion system for various industrial applications including generation Ⅳ nuclear reactors owing to its compact size, high efficiency, and simple layout. Printed Circuit Heat Exchanger (PCHE) not only has high compactness and effectiveness but also can be applied to a wide range of temperature and pressure conditions, making it a very suitable heat exchanger for the sCO₂ Brayton cycle. In this study, a three-dimensional (3-D) designed PCHE channel was proposed and numerically studied. It was found that there are swirling flows in the proposed 3-D PCHE channels owing to the interaction between two flows in different directions. This swirling flow made the local heat transfer coefficient high along the circumferential direction of channels. A comparative evaluation of the thermal-hydraulic performance of investigated channels was conducted by comparing the volume goodness factor with identical hydraulic diameter. As a result, the proposed 3-D PCHE channels showed a higher or comparable thermal-hydraulic performance compared to conventional 2-D PCHE channels. Therefore, the proposed 3-D PCHE channel could be suggested as a PCHE design option for the sCO₂ Brayton cycle. Furthermore, the double-sided straight channel having the swirling flow is expected to have distinctions other than the performance because it is known that the swirling flow can mitigate not only the fouling in heat exchangers but also the heat transfer deterioration of sCO₂.