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Study of aerodynamic noise in low supersonic operation of an axial flow compressorA study of compressor noise is presented, based upon supersonic, part-speed operation of a high hub/tip ratio compressor designed for spanwise uniformity of aerodynamic conditions, having straight cylindrical inlet and exit passages for acoustic simplicity. Acoustic spectra taken in the acoustically-treated inlet plenum, are presented for five operating points at each of two speeds, corresponding to relative rotor tip Mach numbers of about 1.01 and 1.12 (60 and 67 percent design speed). These spectra are analyzed for low and high frequency broadband noise, blade passage frequency noise, combination tone noise and "haystack' noise (a very broad peak somewhat below blade passage frequency, which is occasionally observed in engines and fan test rigs). These types of noise are related to diffusion factor, total pressure ratio, and relative rotor tip Mach number. Auxiliary measurements of fluctuating wall static pressures and schlieren photographs of upstream shocks in the inlet are also presented and related to the acoustic and performance data.
Document ID
19720012199
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Arnoldi, R. A.
(Pratt and Whitney Aircraft East Hartford, CT, United States)
Date Acquired
September 2, 2013
Publication Date
March 5, 1972
Subject Category
Propulsion Systems
Report/Patent Number
PWA-4411
NASA-CR-125811
Accession Number
72N19849
Funding Number(s)
CONTRACT_GRANT: NASW-2249
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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