Axial Magnetic Flux Airflow Integrated Compressor-Generator-Motor Turbojet

Axial Magnetic Flux Airflow Integrated Compressor-Generator-Motor Turbojet (DRC-TOPS-39)
Lowering weight and volume of turbo-machinery for aircraft applications
Innovators at NASA's Armstrong Flight Research Center have developed a compressor-generator-motor turbojet design that integrates the generator into the aerodynamic blade structures of the compression section of turbo-machinery. This lowers both weight and volume compared with conventional turbine generator arrangements in which the turbojet or turbofan drives a separate shaft-driven generator. All manner of other conventional designs suffer from system inefficiencies. Conventional side-mounted generators require the weight of a 90-degree gearbox, while a rear-mounted generator suffers from cooling problems. Armstrong's design offers improvements over these configurations with a flight-weight electromagnetic turbo-generator that is suitable for application to distributed turboelectric systems on aircraft and aids in cooling the system. The unique technology may enable new aircraft configurations and future Turboelectric Distributed Propulsion (TeDP) aircraft designs.

The Technology
The innovation uses the rotating blades of the compressor section to act as structural support for the generator. Since the compressor is the coolest part of the engine, it will reduce the potential for interference with magnetics and associated curie points of the permanent magnets. The placement of the generator in the cooler part of the engine flowpath (fan or compressor) will also improve the electrical insulation system's degradation and serve to improve overall system lifetime. The configuration proposed by Armstrong's design would be an axial magnetic flux permanent magnet generator or motor. The electrical/mechanical interface could serve to deliver power to the shaft of the turbojet/fan or extract power from the shaft. This axial electromagnetic flux design is more efficient for the combined function of aero-thermal heat transfer and generation of electricity. This is due to the relative amount of available cooling surface area, which has an advantage over radial designs given the total system volumetric aspect ratio of the generator/compressor section. When the system is viewed as a thermodynamic cycle, it is more efficient because it is essentially a regenerative cycle, with the heat of generation being fed back into the cycle instead of being released into the ambient surroundings
Turbo-electric compressor-generator CAD drawings
  • Streamlined: Integrates the generator into the blade structure of turbo-machinery, thereby simplifying the overall system design
  • Lower weight: Lowers the weight and volume of the overall system, bypassing the need for a heavy 90-degree gearbox in conventional side-mounted generators
  • Cooler: Eliminates the intrinsic cooling problems of rear-mounted generators by enabling the blades of the compressor to cool the electromagnetic machinery

  • Turboelectric Distributed Propulsion (TeDP) aircraft designs
  • N+3 vehicle concepts
  • Large-class cargo transports
  • Commercial and private aircraft
Technology Details

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