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Quiet High Speed Fan II (22-inch) Duct Mode Characteristics as Measured by the Rotating Rake Mode Measurement System while Operated in the NASA Glenn 9x15 Low Speed Wind Tunnel Wind Tunnel test at a tunnel Mach number of 0.10. This was an entry to investigate the effect of “stator clocking” on noise. The fan consisted of a moderately aft swept rotor and an aft swept set of stator vanes. The fan stage consisted of 22 rotor blades, 50 stator vanes, and 10 downstream support struts. A set of stator vanes designed for lower noise was tested as well as a baseline stator vane set. The stator assembly could be rotated several degrees to adjust the clocking angle between the stator vane pack and the strut assembly. All configurations were with a hard wall duct (no acoustic treatment). The NASA Glenn Research Center’s Rotating Rake Mode Measurement System was utilized to obtain a complete map of the acoustic duct modes present in the ducted fan. The system is a radial rake emersed into the duct that continuously rotates about the duct centerline. For the two stator configurations, data were acquired at several different fan speeds which included nominal, approach, cutback, and takeoff conditions. Analysis of the mode power level results at the fan fundamentals showed the improved designed set resulted in lower rotor-stator and rotor-strut interaction acoustic levels for the interaction modes. Varying the angle between the stators and struts was shown to be a viable method to achieve a minimum in rotor-strut interaction mode power level. Multiple-pure-tones generated by the Quiet High Speed Fan II in the inlet were also measured.
Document ID
20220005239
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Daniel L. Sutliff
(Glenn Research Center Cleveland, Ohio, United States)
Date Acquired
April 4, 2022
Subject Category
Acoustics
Meeting Information
Meeting: 28th AIAA/CEAS Aeroacoustics Conference
Location: Southampton
Country: GB
Start Date: June 14, 2022
End Date: June 17, 2022
Sponsors: Council of European Aerospace Societies, American Institute of Aeronautics and Astronautics
Funding Number(s)
WBS: 081876.02.03.50.10.02.02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Technical Review
Single Expert
Keywords
Turbofan, Duct Modes
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