Design And Optimization Of High Speed Turbine Blades For S-CO₂ Brayton Cycle Power Generation System

In recent years,the research on the Brayton cycle of supercritical carbon dioxide has gradually become a hot topic.As the thermoelectric conversion equipment of supercritical carbon dioxide Brayton cycle system,turbine is the key component to ensure the safe and effective operation of the system.However,the design and inspection process of turbine is complex and challenging.The designer can only obtain the design data that can meet the requirements as much as possible through experience and continuous attempts according to the requirements and objectives obtained by the cycle,which will lead to the waste of a lot of time in the experimental design process and the final result is often not the optimal design.Therefore,the purpose of this paper is to propose a set of complete and simple operation flow S-CO₂turbine blade design and optimization scheme,and establish the corresponding mathematical model.Then the reverse design is completed by the mathematical model to obtain the optimal design parameters of S-CO₂ turbine.This study provides a theoretical basis for the engineering application of S-CO₂ turbine in S-CO₂ BC waste heat power generation system.Different from the traditional two-dimensional turbine blade design,in this study,the rotating machinery design software CFTurbo is used for interactive design to obtain multiple sets of design data and three-dimensional models of axial-flow turbine and radial turbine.Then the three-dimensional models are imported through the fluid simulation software ANSYS-CFX and the boundary conditions are set to obtain the simulation results.Then,taking the turbine design parameters and operation parameters as independent variables,the required mass flow,expansion ratio,isentropic efficiency,output shaft power,nozzle efficiency and other indicators in the turbine simulation results as dependent variables,using SPSS software for multiple nonlinear regression analysis,to explore the influence of turbine design parameters and operation parameters on turbine performance and the internal mechanism.The nonlinear regression model of axial flow turbine and runoff turbine is established by SPSS,and then the optimal design parameters are obtained.The final results show that the mass flow rate,expansion ratio,isentropic efficiency,output shaft work and nozzle efficiency of the axial flow turbine and radial flow turbine are11.81 kg·s^-1,1.30,78.98%,372.93 k W,88.00%and 14.75 kg·s^-1,1.56,86.09%,305.85 k W and 93.01%,respectively,which meet the design requirements.