Theoretical and numerical analysis of conjugate heat transfer for supercritical CO2 flowing in printed circuit heat exchanger

The printed circuit heat exchanger (PCHE) is often utilized for the supercritical CO2 (SCO2) Brayton cycle. This study proposed a assessed method with the dual effects of temperature and pressure to investigate the heat transfer performance (HTP) for PCHE derived from theoretical analysis and numerical validation. The influence of various operating conditions on total and hot-side heat transfer coefficient (HTC) was analyzed. The results showed that the PCHE may achieve better HTP when the critical index was near 1. The assessed way had been verified by utilizing the existing experimental data. The total and hot-side HTC for SCO2-Water PCHE were higher than that of SCO2-SCO2 PCHE, which may increase as cold-side Reynolds number increases. The effect of entropy generation rate for heat transfer on the irreversibility was larger than that of entropy generation rate for viscosity. This study may offer theoretical guidance for optimization of heat exchangers.