The real gas characteristics of supercritical carbon dioxide(S-CO_2) make it difficult to obtain stable convergence results in three-dimensional numerical simulation of S-CO_2 centrifugal compressor

and the time cost of numerical calculation further increases the difficulty of compressor design optimization. To establish a flow calculation method suitable for S-CO_2 centrifugal compressor

three-dimensional numerical simulation is carried out on the compressor to obtain the flow field information and corresponding loss distribution. Then

the onedimensional loss model is superimposed in the conventional flow line curvature method

and the CO_2 compression factor is calculated in segments along the flow line

thus to reflect the real gas compression process. Comparison between the calculation results and the three-dimensional numerical simulation results shows that

the distribution of meridian relative velocity field and enthalpy obtained by streamline curvature method are consistent with the computational Fluid dynamics(CFD) results. The temperature and pressure data at the blade outlet are close to the CFD results

with errors of 0.23% and 1.08%

respectively

and a difference of 1.5% in total static isentropic efficiency. The results indicate that the performance parameters of S-CO_2 centrifugal compressor impeller can be obtained quickly and accurately by using streamline curvature method.