National Aeronautics and Space Administration

Glenn Research Center

Dennis Huff

Mr. Dennis Huff spoke about the “Future Challenges of Aeropropulsion” on July 5, 2012. The design of aircrafts involves many trade studies at the systems level. Considerations include reliability, cost, range, maintainability, payload, passenger comfort, takeoff field length, altitude cruise, landing speed, cruise mach, and safety concerns such as noise, emissions and fuel economy. He discussed the many areas of focus in aeropropulsion research. For subsonic propulsion systems, for example, the focus for engines is on highly integrated propulsion systems with higher power density, lower noise, and lower emissions. He briefly introduced us to turbofan engines and their vital functions, and the connection between higher bypass ratios and increased fuel efficiency. Mr. Huff then further discussed about the subsonic propulsion for which he emphasized the importance of environmental impact caused by burning related fuels. He then provided a set of goals for fuel emissions, fuel burn, and field length for the aircraft had to take-off.

In addition, Mr. Huff introduced the future of aircrafts within the next 40 to 50 years from our present time. One of the few aircrafts he introduced included Open Rotor, which he claimed substantially reduced noise levels; Ultra-High bypass which features low noise and higher fuel efficiency. Lastly, Mr. Huff introduced the embedded engines (Boeing and NASA are working together to create X-48C embedded engine aircraft). He mentioned Alternative Fuels Research that includes the related Fischer-Tropsch processes which may eliminate US’s dependency on fuel from the Middle East.

Mr. Huff also discussed on-going research in supersonic flight for which the primary engineering challenge is the reduction of sonic booms to the level that could be accepted by civilian populations over which these planes may one day fly regularly. This involves a reduction in amplitude of the n-wave which is the pressure wave formed (on its two ends) by the front and rear shock waves formed by the supersonic vehicle. Overall, it was a very good overview of the types and areas of research being conducted in modern aeropropulsive engineering.