NDLI: Comparison of far-field noise for three significantly different model turbofans

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Comparison of far-field noise for three significantly different model turbofans

Content Provider	NASA Technical Reports Server (NTRS)
Author	Woodward, Richard P.
Copyright Year	2008
Description	Far-field noise sound power level (PWL) spectra and overall sound pressure level (OASPL) directivities were compared for three significantly different model fan stages which were tested in the NASA Glenn 9x15 Low Speed Wind Tunnel. The test fans included the Advanced Ducted Propulsor (ADP) Fan1, the baseline Source Diagnostic Test (SDT) fan, and the Quiet High Speed Fan2 (QHSF2) These fans had design rotor tangential tip speeds from 840 to 1474 ft/s and stage pressure ratios from 1.29 to 1.82. Additional parameters included rotor-stator spacing, stator sweep, and downstream support struts. Acoustic comparison points were selected on the basis of stage thrust. Acoustic results for the low tip speed/low pressure ratio fan (ADP Fan1) were thrust-adjusted to show how a geometrically-scaled version of this fan might compare at the higher design thrust levels of the other two fans. Lowest noise levels were typically observed for ADP Fan1 (which had a radial stator) and for the intermediate tip speed fan (Source Diagnostics Test, SDT, R4 rotor) with a swept stator. Projected noise levels for the ADP fan to the SDT swept stator configuration at design point conditions showed the fans to have similar noise levels. However, it is possible that the ADP fan could be 2 to 3 dB quieter with incorporation of a swept stator. Benefits of a scaled ADP fan include avoidance of multiple pure tones associated with transonic and higher blade tip speeds. Penalties of a larger size ADP fan would include increased nacelle size and drag.
File Size	1414237
Page Count	14
File Format	PDF
Alternate Webpage(s)	http://archive.org/details/NASA_NTRS_Archive_20080003867
Archival Resource Key	ark:/13960/t6644qg7j
Language	English
Publisher Date	2008-01-07
Access Restriction	Open
Subject Keyword	Aerodynamics Noise Sound Wind Tunnels Jet Aircraft Noise Noise Reduction Turbofans Far Fields Wind Tunnel Tests Aerodynamic Noise Turbofan Engines Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aircraft Aerospace Engineering Aerospace Aeronautic Space Science
Content Type	Text
Resource Type	Article

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