Investigation on the flow and heat transfer characteristics of supercritical CO2 in printed circuit heat exchanger with asymmetric airfoil fins

Abstract

As an essential component of the supercritical CO2 recompression Brayton cycle, the recuperator has a significant impact on the efficiency and stability of the entire cycle system. The printed circuit heat exchanger is the most suitable heat exchanger for the recuperator in the supercritical CO2 recompression Brayton cycle. To investigate the effects of the structural parameters of the asymmetric AFF on the thermo-hydraulic performance of the printed circuit heat exchangers, simplified 3-D numerical simulation models for the printed circuit heat exchanger with National Advisory Committee for Aeronautics 85XX series asymmetric AFF were built. An optimization method combining an orthogonal experiment and a quadratic polynomial surrogate model with a multi-objective genetic algorithm was proposed to obtain the optimal structural parameters. The results show that the fin thickness, lb, has the most significant effect on the comprehensive performance and fluid-flow performance, and the transverse spacing, lc, has the highest influence on the thermal performance. The optimum structural parameters set are a combination of the transverse spacing of 3.9 mm, the longitudinal spacing of 11.5 mm, and the fin thickness of 0.77mm.