Aerodynamic design and optimization of sCO2 turbomachinery: Two-Stage optimization approach

The application of supercritical CO2 (sCO2) in power generation systems is getting attractive recently owing to high energy efficiency and compact component size, but there are big design challenges for turbines and com-pressors due to the supercritical fluid characteristics. In this paper, a novel turbomachinery design optimization framework, "Turbine-Delta h-Compressor" (T Delta hC) tool, is proposed to generate the optimal flow feature and ge-ometry. The T Delta hC tool based on sequential quadratic programming formulation extends the design parameter search spaces and compares the optimized turbomachinery geometries by coupling with genetic algorithm, its capability is demonstrated by three sCO2 systems with 100, 200 and 250 kW turbine output power under different operating conditions. It is found that the maximum turbine total-to-static efficiency of these systems is 86.99 % and the maximum compressor isentropic efficiency is 77.06 %. In the optimal design case, the system thermal efficiency could reach 33.43 %.