Printed Circuit Heat Exchanger Design, Analysis and Experiment

Abstract

The supercritical carbon dioxide (S-CO2) Brayton cycle has been receiving worldwide attention because of the high thermal efficiency at moderate turbine inlet temperature (450~650℃) due to relatively low compression work near the CO2 critical point (30.98℃, 7.38MPa). Recently, the compact heat exchanger design for the S-CO2 cycle has been one of the main engineering issues. The heat transfer performance and the pressure drop of a heat exchanger need to be precisely predicted for optimizing the S-CO2 Brayton cycle. To predict the thermal hydraulic performance of a heat exchanger, KAIST research team developed a printed circuit heat exchanger (PCHE) design and analysis code; namely KAIST_HXD. For the realistic design, the Reynolds number range of previous experimental correlation for zig-zag channel was extended to 2,000-58,000 by a commercial CFD code. A small size of PCHE designed by KAIST_HXD was manufactured to test the accuracy of the design code. From the experimental result, the designed PCHE showed not only sufficient performance but also small pressure losses. This paper will describe the experimental result of the designed PCHE and the applicability to the S-CO2 cycle.