High Speed Closed Brayton Cycle Turboalternator

A single shaft, low cost, long life, maintenance-free modular turbogenerator scalable from 1 to 100 kWe capacity range for human exploration of the moon and Mars is proposed. Operating at high spin speeds and based on a closed Brayton cycle using a binary He-Xe working fluid, the device combines five key enabling technologies to achieve high cycle and electrical efficiencies. MiTi's innovation is the seamless integration of 1) MiTi's Fifth Generation low power loss; high load, damping and temperature foil bearings with high reliability and long life; 2) a modular configuration that isolates the alternator elements from high temperature for improved thermal management; 3) a high efficiency direct drive permanent magnet high-speed alternator; 4) high adiabatic efficiency aero components; and 5) high effectiveness/low pressure drop ceramic/cermet based recuperator. The specific design has its heritage in an open Brayton cycle turboalternator with a demonstrated specific power 1.6 kW/kg.