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Aeromechanics Analysis of a Distortion-Tolerant Fan with Boundary Layer IngestionA propulsion system with Boundary Layer Ingestion (BLI) has the potential to significantly reduce aircraft engine fuel burn. But a critical challenge is to design a fan that can operate continuously with a persistent BLI distortion without aeromechanical failure -- flutter or high cycle fatigue due to forced response. High-fidelity computational aeromechanics analysis can be very valuable to support the design of a fan that has satisfactory aeromechanic characteristics and good aerodynamic performance and operability. Detailed aeromechanics analyses together with careful monitoring of the test article is necessary to avoid unexpected problems or failures during testing. In the present work, an aeromechanics analysis based on a three-dimensional, time-accurate, Reynolds-averaged Navier-Stokes computational fluid dynamics code is used to study the performance and aeromechanical characteristics of the fan in both circumferentially-uniform and circumferentially-varying distorted flows. Pre-test aeromechanics analyses are used to prepare for the wind tunnel test and comparisons are made with measured blade vibration data after the test. The analysis shows that the fan has low levels of aerodynamic damping at various operating conditions examined. In the test, the fan remained free of flutter except at one near-stall operating condition. Analysis could not be performed at this low mass flow rate operating condition since it fell beyond the limit of numerical stability of the analysis code. The measured resonant forced response at a specific low-response crossing indicated that the analysis under-predicted this response and work is in progress to understand possible sources of differences and to analyze other larger resonant responses. Follow-on work is also planned with a coupled inlet-fan aeromechanics analysis that will more accurately represent the interactions between the fan and BLI distortion.
Document ID
20180002211
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Bakhle, Milind A.
(NASA Glenn Research Center Cleveland, OH, United States)
Reddy, T. S. R.
(Toledo Univ. Toledo, OH, United States)
Coroneos, Rula M.
(NASA Glenn Research Center Cleveland, OH, United States)
Min, James B.
(NASA Glenn Research Center Cleveland, OH, United States)
Provenza, Andrew J.
(NASA Glenn Research Center Cleveland, OH, United States)
Duffy, Kirsten P.
(Toledo Univ. Toledo, OH, United States)
Stefko, George L.
(NASA Glenn Research Center Cleveland, OH, United States)
Heinlein, Gregory S.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
April 10, 2018
Publication Date
January 8, 2018
Subject Category
Fluid Mechanics And Thermodynamics
Aircraft Propulsion And Power
Structural Mechanics
Report/Patent Number
GRC-E-DAA-TN49763
Meeting Information
Meeting: SciTech Forum 2018
Location: Kissimmee, FL
Country: United States
Start Date: January 8, 2018
End Date: January 12, 2018
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 081876.02.03.50.06.02.01
CONTRACT_GRANT: NNC13BA10B
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Propulsion Aeroelasticity
Forced Response
Boundary Layer Ingestion
Fan Flutter
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