Aiming at the micro radial-inflow turbine with helium-xenon mixed working fluid adopted in the closed Brayton cycle of space nuclear power systems, one-dimensional aerodynamic design, three-dimensional geometric modeling and refined numerical simulation are carried out in this paper. The space nuclear power system with closed Brayton cycle imposes stringent requirements on the operational efficiency of turbomachinery, and the equipment must satisfy strict constraints on dimension and lightweight design. The helium-xenon mixed working fluid can adapt to such severe operating conditions by adjusting its thermophysical properties, making it a preferred working fluid for micro radial-inflow turbines with important research and application values. This paper systematically summarizes the aerodynamic design method and numerical simulation framework for heliumxenon turbines, and designs a radial-inflow helium-xenon turbine based on a 100 kWe-class Brayton cycle for space power. In the design, a helium-xenon mixture with a molar mass of approximately 40 g/mol is selected, in which the volume fraction of helium is 71.7% and that of xenon is 28.3%. The designed turbine operates at a rotational speed of 45000 rpm, with a working fluid mass flow rate of 3.785 kg/s, an inlet total temperature of 1150 K and an expansion ratio of 1.9. Numerical simulations are performed on the turbine. The simulation results show that the turbine can achieve an output power of 437.765 kW and an aerodynamic efficiency of 87.7%. The research results effectively verify the energy conversion performance of this micro radial-inflow turbine using helium-xenon mixed working fluid, and can provide reliable operating condition references and technical support for subsequent turbine aerodynamic optimization, performance analysis and engineering applications.

Closed Brayton Cycle; Helium–Xenon (He-Xe) Mixture; Numerical Simulation; Radial Inflow Turbine