CFD aided approach to design printed circuit heat exchangers for supercritical CO2 Brayton cycle application

• CFD analyses were performed to find performance of PCHE for supercritical CO2 power cycle.
• CFD results were obtained beyond the limits of existing correlations.
• Designs of different PCHEs with different correlations were compared.
• A new CFD-aided correlation covering a wider Reynolds number range was proposed.

While most conventional PCHE designs for working fluid of supercritical CO2 require an extension of valid Reynolds number limits of experimentally obtained correlations, Computational Fluid Dynamics (CFD) code ANSYS CFX was used to explore validity of existing correlations beyond their tested Reynolds number ranges. For heat transfer coefficient correlations, an appropriate piece-wising with Ishizuka’s and Hesselgreaves’s correlation is found to enable an extension of Reynolds numbers. For friction factors, no single existing correlation is found to capture different temperature and angular dependencies for a wide Reynolds number range. Based on the comparison of CFD results with the experimentally obtained correlations, a new CFD-aided correlation covering an extended range of Reynolds number 2000–58,000 for Nusselt number and friction factor is proposed to facilitate PCHE designs for the supercritical CO2 Brayton cycle application.