Study on thermal-hydraulic characteristics of CO2-water printed circuit heat exchanger with different structural parameters

Abstract

• Simulation work is carried out to investigate the effect of structural parameter. • Separated flow shows high correlation with flow and heat transfer performance. • Comprehensive performance is compared among pitch, zigzag angle and bend radius. The printed circuit heat exchanger is a promising candidate in supercritical CO 2 Brayton cycle due to its advantages with high compactness and high resistance to pressure and temperature. In this paper, the simulation work of zigzag channel PCHE validated by experiment are conducted with different pitches (10 mm − 25 mm), zigzag angles (90° − 165°) and bend radius (0.2 mm − 7.0 mm) to investigate the thermal-hydraulic characteristics of zigzag channel PCHE using for precooler. Based on the 1/2 pitch-averaged results, it is found that the heat transfer performance and flow resistance change considerably with the variation of zigzag angle and bend radius. Meanwhile, the heat transfer coefficient and friction factor present a fluctuation change in local position. The high correlation is found between separated flow and friction factor based on the analysis of separated flow ratio. Besides, with the comparison of comprehensive factor PEC, the optimal structure of PCHE is inconsistent between the regions near and away from the pseudo-critical. Furthermore, the zigzag angle and bend radius appear to have greater influence than pitch on PCHE performance according to the analysis by noise performance statistics (NPS).