Study On Performance Optimization Of Supercritical Carbon Dioxide Centrifugal Compressor

Supercritical carbon dioxide?SCO₂?centrifugal compressor has the advantages of high reliability,small volume,light weight and high efficiency.It is considered to be one of the most promising power equipment in the field of new energy.Based on the one-dimensional flow theory and quasi-three-dimensional design method,the three-dimensional model of SCO₂ centrifugal compressor is obtained from the design thermodynamic parameters,and the flow field and aerodynamic performance of the centrifugal compressor are studied.In addition,the geometric and aerodynamic parameters of the flow-through components of SCO₂ centrifugal compressor are analyzed and optimized by numerical calculation,the final total pressure ratio of SCO₂ centrifugal compressor can reach 1.78,and the polytropic efficiency can reach 87.2%,which meets the design requirements.Finally,the strength of the impeller is checked and calculated.The main work of this paper is as follows:Firstly,the basic principle of computational fluid dynamics?CFD?,the control equation and the real gas model of carbon dioxide are introduced,and the three-dimensional model establishment,mesh partition and parameters setting of numerical simulation of SCO₂ centrifugal compressor are given.Then,the aerodynamic performance of the impeller of SCO₂ centrifugal compressor is numerically calculated.The impeller was optimized from four angles:installation angle of impeller outlet,length of shunt blade,circumferential position of shunt blade and number of blades.The influence of different structural parameters on the aerodynamic performance of SCO₂ centrifugal compressor is analyzed.Furthermore,the optimization analysis of vaneless diffuser and volute is carried out.The influence of three structural parameters,the type of vaneless diffuser,the sectional area of volute and the radius of spiral tongue,on the aerodynamic performance of SCO₂centrifugal compressor is studied.At the same time,the performance of SCO₂ centrifugal compressor under different working conditions is studied.Finally,the impeller strength of SCO₂ centrifugal compressor is studied.The influence of aerodynamic force and centrifugal force acting alone and together on the impeller strength at rated condition is analyzed,and the modal analysis is carried out.The suitable material for impeller manufacturing is selected through comparative study,and the law of influence of the maximum equivalent stress and total deformation of impeller under different working flow and working speed are obtained..The results can provide some theoretical basis for the design and development of SCO₂ centrifugal compressor.