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Acoustic Mode Measurements in the Inlet of a Model Turbofan Using a Continuously Rotating RakeComprehensive measurements of the spinning acoustic mode structure in the inlet of the Advanced Ducted Propeller (ADP) have been completed. These measurements were taken using a unique and previously untried method which was first proposed by T.G. Sofrin. A continuously rotating microphone system was employed. The ADP model was designed and built by Pratt & Whitney and tested in the NASA Lewis 9- by 15-foot Anechoic Wind Tunnel. Three inlet configurations were tested with cut-on and cutoff stator vane sets. The cutoff stator was designed to suppress all modes at the blade passing frequency. Rotating rake measurements indicate that several extraneous circumferential modes were active. The mode orders suggest that their source was an interaction between the rotor and small interruptions in the casing tip treatment. The cut-on stator produced the expected circumferential modes plus higher levels of the unexpected modes seen with the cutoff stator.
Document ID
19930007516
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Heidelberg, Laurence J.
(NASA Lewis Research Center Cleveland, OH, United States)
Hall, David G.
(Sverdrup Technology, Inc. Brook Park, OH, United States)
Date Acquired
September 6, 2013
Publication Date
December 1, 1992
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
NAS 1.15:105989
E-7496
AIAA PAPER 93-0598
NASA-TM-105989
Meeting Information
Meeting: Aerospace Sciences Meeting
Location: Reno, NV
Country: United States
Start Date: January 11, 1993
End Date: January 14, 1993
Sponsors: American Institute of Aeronautics and Astronautics (AIAA)
Accession Number
93N16705
Funding Number(s)
PROJECT: RTOP 535-03-10
Distribution Limits
Public
Copyright
Public Use Permitted.
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