Optimization of fin for rectangular microchannel printed circuit heat exchanger using supercritical CO2 as working fluid

Abstract

To improve the performance of printed circuit heat exchanger (PCHE) in the supercritical carbon dioxide (SCO₂) Brayton cycle system, the mathematic-physical model of the heat exchange unit was established, based on a new-type rectangular microchannel PCHE (RM-PCHE) manufacturing by total-etching technology in this study. And the influence mechanism and laws on the flow and heat transfer of the different fin distributions and shapes were numerically investigate. Results showed average simulation deviations of 0.9 % for outlet temperature and 13.3 % for heat transfer quantity, meeting accuracy requirement. Uniform fin distribution at 10 mm intervals significantly reduced pressure drop and improved comprehensive heat transfer performance by 14.8 %. When elliptical and airfoil fins were selected for the hot-side and cold-side channels, the flow characteristic significantly improved and the heat transfer process became more stable, improving the single-side performance by 15.9 % and 12.3 %, respectively.