Aerodynamic design optimization of radial-inflow turbine in supercritical CO2 cycles using a one-dimensional model

The supercritical CO2 (S-CO2) power cycles have been receiving an increasing amount of attention due to their advantages, which include high efficiency, compactness, environmentally friendliness, etc. The radial-inflow turbine (RIT) is a key component of small-scale S-CO2 cycles, and its efficiency has a significant impact on the cycle efficiency. In this paper, an optimization design approach is proposed to quickly acquire a preliminary optimal RIT configuration when S-CO2 is applied as working fluid. The approach combines a one-dimensional (1D) design method and an optimization algorithm. Firstly, based on the 1D thermodynamic model, two programs have been developed for the S-CO2 RITs preliminary design and off-design performance predictions. Secondly, an optimum set of loss correlations has been found and validated to accurately predict various losses of the S-CO2 RITs. Finally, the optimization is carried out to maximize the total-static efficiency of the S-CO2 RITs. The results show that the predicted performance using the loss correlations set found in this paper agree well with both the experimental and the CFD simulation results. In addition, an S-CO2 RIT design using the proposed optimization design approach has a superior performance under design and off-design conditions.