Analysis of flow and heat transfer performance of different types of flow channels in PCHE for pre-coolers

Abstract

The shape of fins in flow channels of Printed Circuit Heat Exchangers (PCHE) significantly affects the heat exchanger performance. In the pre-cooler condition of the marine supercritical carbon dioxide (sCO2) Brayton cycle power generation system, this study focuses on three typical discontinuous flow channel Printed Circuit Heat Exchangers (PCHEs). The investigation involves a numerical analysis of flow and heat transfer performance using Computational Fluid Dynamics (CFD) method. The comparative consequences illuminate that the rectangular fin channel exhibits the optimal heat transfer performance, and temperature drops are 1.18 times and 1.23 times, exceeding those of airfoil and rhombic fin channels, respectively. All three flow channels show different degrees of temperature drop reduction along the direction of fluid flow. However, the rectangular fin channel demonstrates the worst flow performance, as pressure drops are 16.6 times and 17.8 times, higher than those of airfoil and rhombic fin channels, respectively. By calculating the values of Nu/f and Q/?p, the comprehensive performance of each flow channel is ranked from high to low as follows: airfoil fin channel, rhombic fin channel, and rectangular fin channel. This research provides guidance for optimizing the design and applying PCHEs in engineering for marine sCO2 Brayton cycle pre-coolers.