Supercritical carbon dioxide turbomachinery development using scaling methodology, computational fluid dynamics and experimental testing in aeroloop

Supercritical carbon dioxide (SCO2) turbomachinery design experience is limited. This paper examines similarity-based scaling strategy to develop a radial inflow turbine and a centrifugal compressor from existing proven designs for a 50 kWe SCO2 Brayton cycle. The SCO2 turbine and compressor are developed from well-established NASA 1730 air turbine and NASA 4613 radial pump, respectively. Computational fluid dynamic (CFD) simulations with air and SCO2 and experimental testing in aeroloop are carried out for the developed turbomachinery. The results are compared with original NASA test data. For the turbine, the CFD simulation and experimental results were in good agreement with NASA data. For the compressor, CFD simulation results with SCO2 showed good conformance especially the efficiency values, which were much lower for air. The compressor experimental results were well away from the NASA data when head rise coefficient was considered, but the flow coefficient zone coincided with that of simulation.