Aerodynamic Design, Model Test, and CFD Analysis for a Multistage Axial Helium Compressor

Results of an aerodynamic design study for the multistage axial helium compressor of a 300 MWe class nuclear gas turbine are presented. Helium compressor aerodynamics is challenged by the characteristically narrow and numerous-stage flow path, which enhances loss effects of blade surface and end wall boundary layer growth, secondary and clearance flows, and any occurrence of flow separation and stage mismatch. To meet the high efficiency and reliability requirements of the nuclear application, base line and advanced aerodynamic design techniques are incorporated with the intent to mitigate the flow path adverse working condition and losses. Design validation is carried out by test and test-calibrated 3D viscous CFD analyses of a subscale model compressor. In addition to verifying the success of the design intent, the data and computational insights of overall performance and internal flow behavior are used to establish a performance model based on Reynolds number and used for the full compressor performance prediction. The model applicable to all geometrically similar designs shows sensitive responses of helium compressor aerodynamic efficiency to Reynolds number and surface roughness. Presented in the paper is the first modern design with experimental validation for multistage axial helium compressor that concerned itself with a difficult past but which has strong current interest in countries now developing thermal and fast nuclear gas reactors.