Thermodynamic Analysis of Supercritical Carbon Dioxide Brayton Cycle Based on the Prediction of the Radial Inflow Turbine Efficiency

Turbine is one of the core components of the supercritical carbon dioxide (S-CO₂) cycle. Generally, the radial inflow turbine is adopted for the small mass flow rate cases. The turbine efficiency is closely related to the cycle design parameters. The turbine efficiency is usually set as a constant value in S-CO₂ cycle studies. According to our survey, there are few researches about the influence of the turbine efficiency prediction on the S-CO₂ cycle performances. In this paper, the S-CO₂ recompression cycle model based on the one dimensional (1D) radial inflow turbine is proposed. Under different cycle parameters, the comparison of S-CO₂ cycle thermodynamic performances based on 1D and constant turbine efficiency is conducted. The results reveal that the proper constant turbine efficiency can be applied when cycle parameters vary. However, it's important to investigate the off-design turbine efficiency when the heat source mass flow rate changes.