Aerothermodynamic Design and Numerical Investigation of Supercritical Carbon Dioxide Turbine

Abstract

Supercritical Carbon Dioxide (SCO2) is considered as a potential working fluid in power conversion systems, as SCO2 power cycle has several advantages of the modest turbine inlet temperature, smaller compression work and more compact layout compared with some traditional cycle. For SCO2 turbines, the main challenge is to achieve a design scheme to meet the aerothermodynamics request, geometry restriction, structural strength, and component functionality requirements while in consideration of the applicable materials. This paper conducts the selection and verification of SCO2 turbine types and rotational speeds when the required power outputs are 15MW and 1.5MW. The type of turbine for the 15MW is an axial one and for the 1.5MW is a radial one, respectively. A numerical investigation on the aerothermodynamics design, geometrical design, and overall performance prediction of the two different SCO2 turbines are performed. Actual properties of the SCO2 are input to the model from the Refprop database provided by the US National Institute of Standards and Technology (NIST). The detailed aerodynamic analysis is carried out based on a complete three-dimensional model of the whole passages of nozzle vane and rotor flow field by the commercial CFD software-NUMECA. In addition, the strength analysis of the turbine is performed using the commercial software ANSYS/Mechanical, and the effect of the working fluid pressure load is taken into consideration.