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Dynamic Analysis of the hFan, a Parallel Hybrid Electric Turbofan EngineNASA and a variety of aerospace industry stakeholders are investing in conceptual studies of electrified aircraft, including parallel hybrid electric aircraft such as the Subsonic Ultra Green Aircraft Research (SUGAR) Volt. At this point, little of the work published in the literature has examined the transient behavior of the turbomachinery in these systems. This paper describes a control system built around the hFan, the parallel hybrid electric turbofan engine designed for the SUGAR Volt concept aircraft. This control system is used to show that the hFan, running with its baseline concept of operations, is capable of transient operation throughout the envelope. The design parameters of this controller are varied to assess the amount of operability margin built into the engine design, and whether this margin can be reduced to enable more aggressive designs, that may feature better fuel economy. Further, studies are performed as parameters for the hFan electric motor are varied to determine how the motor impacts the engine's need for transient operability margin. The studies suggest that the engine may be redesigned with as much as a 3% reduction in high pressure compressor stall margin. It was also demonstrated that appropriate design and control of the electric motor may be able to buy an additional 0.5% stall margin reduction or a turbine inlet temperature reduction of 35 degR, as tested at the sea-level static condition.
Document ID
Document Type
Conference Paper
Thomas, George L.
(N and R Engineering and Management Services Parma Heights, OH, United States)
Culley, Dennis E.
(NASA Glenn Research Center Cleveland, OH, United States)
Kratz, Jonathan L.
(NASA Glenn Research Center Cleveland, OH, United States)
Fisher, Kenneth L.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
September 17, 2018
Publication Date
July 7, 2018
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
Meeting Information
Meeting: AIAA/SAE/ASEE Joint Propulsion Conference
Location: Cincinnati, OH
Country: United States
Start Date: July 7, 2018
End Date: July 13, 2018
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 081876.
Distribution Limits
Public Use Permitted.
hybrid electric
jet engine
systems analysis
gas-turbine engine
dynamic systems analysis
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