Meanline Design and Aerodynamic 3D RANS Investigations of a Multistage Helium Axial Compressor

A mean line aerodynamic design and analysis of a multistage helium gas axial flow compressor is presented for a High-Temperature Gas Reactor (HTGR) application. The multistage axial flow compressor design geometry from mean line design is based on a free vortex design method and targeted for achieving high loading, high polytropic efficiency, and is further tuned and investigated for optimum performance by performing three-dimensional Reynolds Averaged Navier Stokes (3D RANS) CFD studies. Performance of the axial compressor and key design quantities are compared with similar previous designs to highlight robustness of the presented design methodology. The design studies also discuss the impact of selecting optimum parameters like thickness to chord length of rotor blades in spanwise direction from hub of the blades to shroud of the blades. Key loss-causing phenomena are identified through 3D RANS CFD analysis, with the intent to improve the final design. Further, The presented designs are verified by 3D RANS CFD analysis for achieving high aerodynamic polytropic efficiency, targeted design pressure ratio while maintaining high blade loading, and negligible flow separation at the design point. Such a design can also reduce the number of stages for typical HTGR applications, thereby lowering the overall weight of the large multistage axial flow compressor.