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Turbomachinery noise studies of the AiResearch QCGAT engine with inflow controlThe AiResearch Quiet Clean General Aviation Turbofan engine was tested on an outdoor test stand to compare the acoustic performance of two inflow control devices (ICD's) of similar design, and three inlet lips of different external shape. Only small performance differences were found. Far-field directivity patterns calculated by applicable existing analyses were compared with the measured tone and broadband patterns. For some of these comparisons, tests were made with an ICD to reduce rotor/inflow disturbance interaction noise, or with the acoustic suppression panels in the inlet or bypass duct covered with aluminum tape to determine hard wall acoustic performance. The comparisons showed that the analytical expressions used predict many directivity pattern features and trends, but can deviate in shape from the measured patterns under certain engine operating conditions. Some patterns showed lobes from modes attributable to rotor/engine strut interaction sources.
Document ID
19810023414
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Mcardle, J. G. (NASA Lewis Research Center Cleveland, OH, United States)
Homyak, L. (NASA Lewis Research Center Cleveland, OH, United States)
Chrulski, D. D. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 4, 2013
Publication Date
January 1, 1981
Subject Category
Acoustics
Report/Patent Number
E-977
NASA-TM-82694
Meeting Information
Meeting: Aeroacoustic Conf.
Location: Palo Alto, CA
Country: United States
Start Date: October 5, 1981
End Date: October 7, 1981
Sponsors: AIAA
Accession Number
81N31957
Funding Number(s)
PROJECT: RTOP 505-32-02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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