Closed Brayton Cycle Engine Starter/Generator Cooling

Abstract

A Closed Brayton Cycle (CBC) engine is a prime candidate to convert heat from a reactor to electric power for space missions. The engine concept incorporates a permanent magnet starter/generator mounted on the CBC engine shaft. The starter/generator stator winding insulation system is one potential life-limiting item in the CBC engine. Successful completion of the long missions currently anticipated for the CBC engines will require temperature control of the generator stator windings to assure that these planned long lives are accomplished. Cooling flow is also required for the bearings and to remove the windage loss from the CBC. The preliminary thermal management concept for the engine is to use the CBC working fluid to provide the required cooling. This paper presents a conceptual design of a CBC turboalternator thermal management approach.