Design and Performance Evaluation of a 10:1 Pressure Ratio Centrifugal Compressor Impeller

Small gas turbine engines for advanced helicopter application and for auxiliary power have strong interest in centrifugal compressors, where high pressure ratios are required in a single stage. But there are few single stage centrifugal compressors capable of pressure-ratios around 10:1, due to stress considerations which severely limit the compressor’s safety, durability and life expectancy. In this work, design considerations are carried out for single stage centrifugal impeller with a pressure ratio of 10:1 and mass flow of 3 kg/s. One-D design procedure is used to compute the skeletal geometry of the impeller and to set a rough description of the flow at inlet and outlet. The theoretical head will be evaluated from Euler’s equation using slip factor. Determining the pressure ratio and efficiency of the impeller are achieved through evaluation of the slip factor and the internal and external losses. The losses evaluated in the impeller are those due to incidence, transonic inlet, skin friction, blade loading, shroud clearance, and recirculation. The design procedure adopted will be verified and compared with the well-documented Eckardt impellers and data. After one-D design, three-D geometry of the impeller is developed, and CFD flow simulation of the impeller flow is carried out to determine the performance of the impeller.