Open Source Axial Compressor Mean-Line Design Tool for Supercritical Carbon Dioxide

Abstract This paper presents an open-source axial compressor design code developed for applications using Supercritical CO2 (S-CO2). Real property tables are generated using REFPROP (Reference Fluid Thermodynamic and Transport Properties Database) linked to MATLAB. These tables are created and are provided for S-CO2 and could be created for any fluid in the database. At this time, only a single-phase fluid has been implemented. The tables are imported into the mean-line code and are interpolated with cubic splines to calculate real properties based on two given properties. The mean-line code is written in Python to allow portability and convenient plotting capability. The inputs are simple ascii files with the overall compressor details, stage data, and an optional IGV file. The code uses the axial flow equations of continuity, energy, and angular momentum in addition to velocity triangles to calculate state properties at every station. A free vortex assumption at each between-blade row station is used to calculate information at hub, pitch, and tip. The input for each stage includes the Mach number and absolute flow angle at the rotor leading edge in addition to the total enthalpy rise across each rotor. Loss coefficients, solidity, aspect ratio and axial spacing are also specified for each blade row along with blockage to account for wakes, boundary layers, and bleed. A hub radius is also specified. These parameters allow for a complete set of realistic inputs for the design of axial compressors using S-CO2 as the working fluid. The output can be used to assess the design and is used as the start of higher fidelity design.