Experimental and Numerical Study of an 80-kW Zigzag Printed Circuit Heat Exchanger for Supercritical CO2 Brayton Cycle

In this study, an experimental system was built to investigate the global performance of an 80-kW zigzag printed circuit heat exchanger (PCHE). It could meet the requirement of the pre-cooler for the supercritical carbon dioxide (S-CO2) Brayton power cycle and the modified effectiveness considering the pinch point is between 61.5% and 79.3%. When the outlet S-CO2 temperature is near the pseudo-critical point, the thermo-physical properties have more effects on heat transfer performance compared to flow characteristics. For the local performance, the mass flow rates of both sides have crucial influences on the location where the peak of S-CO2 Nusselt number occurs while only the S-CO2 flow rate affects the variation of the peak value. In addition, the influence of the radius of curvature on the secondary-flow should not be ignored. In the end, new empirical correlations were proposed considering the drastic variations of the Prandtl number.