The high aerodynamic performance, strength reliability and vibration reliability are three aspects of radial inflow turbine impellers design. This paper mainly presents an investigation on the first aspect but take into account the strength evaluation for a 100kW microturbine unit. Firstly, a thermodynamic design of the radial inflow turbine is carried out, and some important parameters are obtained. Then, the traditional cylinder parabolic geometrical design method is applied to the impeller design. The results of FEM evaluation show the impeller’s maximum stress exceeds the limitations of the impeller material, and the magnitude of centrifugal stress has distinct difference between the suction and the pressure side at the impeller hub. Therefore, a positive axial displacing method and its combination with skewing technique are proposed and developed to solve the strength problem, and the final impeller is designed with inlet relative flow incidence angle of the impeller reaches −32 degree from the radial direction. The numerical analyses using FEM and CFD codes indicate that the final designed impeller satisfies the strength requirements and shows good aerodynamic performance. Furthermore, a 3D Navier-Stokes solver is applied to evaluate the aerodynamic performance of the radial inflow turbine under stage environment and to investigate the detailed flow characteristics of the final designed impeller. As a result, the radial inflow turbine of 100kW microturbine unit has high aerodynamic performance with good consideration on the terms of turbine structure and stress limitations.

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