Design of drive unit in closed Brayton system for 10 kWe space reactor
According to the characteristics of high energy density and long life of space reactor,a design scheme of centrifugal compressor driven by gas foil bearing and high efficiency radial flow impeller is proposed.Based on the specific flow rate,pressure,power and efficiency,the aerodynamic design of the impeller is carried out,and the high efficiency compressor and the high efficiency radial turbine model are obtained.Based on the finite element method,the top foil deformation of the radial air foil bearing is expressed by Euler beam and thick plate model,and solved by the Reynolds equation.The calculation results of the thick plate model accurately reflect the deformation of the foil along the axial direction.It is more reasonable to obtain the dynamic stiffness and damping coefficient of the bearing based on this thick plate model.Based on the thick plate model,the dynamic stiffness and damping coefficient of the bearing are obtained.In this paper,the critical speed of rotor system and the minimum take-off speed of closed Brayton system are obtained by using a reasonable bearing model.The rotor system has better stability under rated conditions from the linear axis trajectory.At last,the load-bearing characteristics of thrust foil bearing are analyzed,and the attention points for assembly are put forward.This research provides theoretical guidance for the development of a prototype driving unit of 10 kWe space reactor closed Brayton system.
space nuclear reactorBrayton systemcentrifugal compressorgas foil bearingrod fastening rotor
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