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Extending the Operational Envelope of a Turbofan Engine Simulation into the Sub-Idle RegionIn many non-linear gas turbine simulations, operation in the sub-idle region can lead to model instability. This paper lays out a method for extending the operational envelope of a map based gas turbine simulation to include the sub-idle region. This method develops a multi-simulation solution where the baseline component maps are extrapolated below the idle level and an alternate model is developed to serve as a safety net when the baseline model becomes unstable or unreliable. Sub-idle model development takes place in two distinct operational areas, windmilling/shutdown and purge/cranking/ startup. These models are based on derived steady state operating points with transient values extrapolated between initial (known) and final (assumed) states. Model transitioning logic is developed to predict baseline model sub-idle instability, and transition smoothly and stably to the backup sub-idle model. Results from the simulation show a realistic approximation of sub-idle behavior as compared to generic sub-idle engine performance that allows the engine to operate continuously and stably from shutdown to full power.
Document ID
20160009115
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Chapman, Jeffryes W.
(Vantage Partners, LLC Brook Park, OH, United States)
Hamley, Andrew J.
(Alabama Univ. Huntsville, AL, United States)
Guo, Ten-Huei
(NASA Glenn Research Center Cleveland, OH United States)
Litt, Jonathan S.
(NASA Glenn Research Center Cleveland, OH United States)
Date Acquired
July 18, 2016
Publication Date
July 1, 2016
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
GRC-E-DAA-TN31401
NASA/TM-2016-219110
AIAA-2016-1043
E-19233
Meeting Information
Meeting: SciTech 2016
Location: San Diego, CA
Country: United States
Start Date: January 4, 2016
End Date: January 8, 2016
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 284848.02.05.03.02.03
CONTRACT_GRANT: NNC12BA01B
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
aerothermodynamics
system modeling
gas path dynamics
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