Considerations for the design of inlet flow conditioners for static fan noise testing

1979 ◽  
Author(s):  
R. GINDER ◽  
R. KENISON ◽  
A. SMITH
Keyword(s):  
Fan Noise ◽  
Inlet Flow

scholarly journals Characteristics of an Anechoic Chamber for Fan Noise Testing

1977 ◽  
Author(s):  
J. A. Wazyniak ◽  
L. M. Shaw ◽  
J. D. Essary
Keyword(s):  
Mechanical Design ◽  
Full Scale ◽  
Anechoic Chamber ◽  
Nasa Lewis Research ◽  
Design Features ◽  
Fan Noise ◽  
Inlet Flow ◽  
Noise Characteristics ◽  
Scale Levels ◽  
Acoustic Evaluation

Acoustical and mechanical design features of NASA Lewis Research Center’s engine fan noise facility are described. Acoustic evaluation of the 1420-m (50,000-ft) chamber, which is lined with an array of stepped wedges, is described. Results from the evaluation in terms of cut-off frequency and non-anechoic areas near the walls are detailed. Fan models with 0.51-m (20-in.) diameters are electrically driven to 20,600 rpm in either the inlet mode (drawing air from the chamber) or exhaust mode (discharging air into the chamber) to facilitate study of both fore and aft fan noise. Inlet noise characteristics of the first fan tested, the JT8D Refan, are discussed and compared to full-scale levels. Turbulence properties of the inlet flow and acoustic results are compared with and without a turbulence reducing screen over the fan inlet.

Application of acoustic analogy to automotive engine-cooling fan noise prediction

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 1095-1098 ◽  
Author(s):  
Jeonghan Lee ◽  
Kyungseok Cho ◽  
Soogab Lee
Keyword(s):  
Noise Prediction ◽  
Acoustic Analogy ◽  
Fan Noise ◽  
Automotive Engine ◽  
Engine Cooling ◽  
Cooling Fan

An acoustic liner design methodology based on a statistical source model

2021 ◽  
pp. 1475472X2110238
Author(s):  
Douglas M Nark ◽  
Michael G Jones
Keyword(s):  
Design Methodology ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Flight Test ◽  
Source Model ◽  
Practical Implementation ◽  
Source Information ◽  
Fan Noise ◽  
Future Design ◽  
Acoustic Liner

The attenuation of fan tones remains an important aspect of fan noise reduction for high bypass ratio turbofan engines. However, as fan design considerations have evolved, the simultaneous reduction of broadband fan noise levels has gained interest. Advanced manufacturing techniques have also opened new possibilities for the practical implementation of broadband liner concepts. To effectively address these elements, practical acoustic liner design methodologies must provide the capability to efficiently predict the acoustic benefits of novel liner configurations. This paper describes such a methodology to design and evaluate multiple candidate liner configurations using realistic, three dimensional geometries for which minimal source information is available. The development of the design methodology has been guided by a series of studies culminating in the design and flight test of a low drag, broadband inlet liner. The excellent component and system noise benefits obtained in this test demonstrate the effectiveness of the broadband liner design process. They also illustrate the value of the approach in concurrently evaluating multiple liner designs and their application to various locations within the aircraft engine nacelle. Thus, the design methodology may be utilized with increased confidence to investigate novel liner configurations in future design studies.

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