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Effect of rotor design tip speed on noise of a 1.21 pressure ratio model fan under static conditionsPreliminary results are presented for a reverberant-field noise investigation of three fan stages designed for the same overall total pressure ratio of 1.21 at different rotor tip speeds (750, 900, and 1050 ft/sec). The stages were tested statically in a 15-inch-diameter model lift fan installed in a wing pod located in the test section of a wind tunnel. Although the fan stages produced essentially the same design pressure ratio, marked differences were observed in the variation of fan noise with fan operating speed. At design speed, the forward-radiated sound power level was approximately the same for the 750 ft/sec and 900 ft/sec stages. For the 1050 ft/sec stage, the design-speed forward-radiated power level was about 7 db higher due to the generation of multiple pure tone noise.
Document ID
19730017287
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Loeffler, I. J.
(NASA Lewis Research Center Cleveland, OH, United States)
Lieblein, S.
(NASA Lewis Research Center Cleveland, OH, United States)
Stockman, N. O.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 2, 2013
Publication Date
January 1, 1973
Subject Category
Aircraft
Report/Patent Number
E-7555
NASA-TM-X-68243
Meeting Information
Meeting: 1973 Winter Ann. Meeting of the ASME
Location: Detroit, MI
Country: United States
Start Date: November 11, 1973
End Date: November 15, 1973
Accession Number
73N26014
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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