A Method to Further Reduce the Perceived Noise of Low Tip Speed Fans

A Method to Further Reduce the Perceived Noise of Low Tip Speed Fans
Title A Method to Further Reduce the Perceived Noise of Low Tip Speed Fans PDF eBook
Author
Publisher
Pages 28
Release 2000
Genre
ISBN

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A Method to Further Reduce the Perceived Noise of Low Tip Speed Fans

A Method to Further Reduce the Perceived Noise of Low Tip Speed Fans
Title A Method to Further Reduce the Perceived Noise of Low Tip Speed Fans PDF eBook
Author National Aeronautics and Space Administration (NASA)
Publisher Createspace Independent Publishing Platform
Pages 38
Release 2018-06-16
Genre
ISBN 9781721236114

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The use of low tip speed, high bypass ratio fans is a method for reducing the noise of turbofan jet engines. These fans typically have a low number of rotor blades and a number of stator vanes sufficient to achieve cut-off of the blade passing tone. Their perceived noise levels are typically dominated by broadband noise caused by the rotor wake turbulence - stator interaction mechanism. A 106 bladed, 1100 ft/sec takeoff tip speed fan, the Alternative Low Noise Fan, has been tested and shown to have reduced broadband noise. This reduced noise is believed to be the result of the high rotor blade number. Although this fan with 106 blades would not be practical with materials as they exist today, a fan with 50 or so blades could be practically realized. A noise estimate has indicated that such a 50 bladed, low tip speed fan could be 2 to 3 EPNdB quieter than an 18 bladed fan. If achieved, this level of noise reduction would be significant and points to the use of a high blade number, low tip speed fan as a possible configuration for reduced fan noise. Dittmar, James H. Glenn Research Center NASA/TM-2000-210457, E-12453, NAS 1.15:210457

Analytical Parametric Investigation of Low Pressure Ratio Fan Noise

Analytical Parametric Investigation of Low Pressure Ratio Fan Noise
Title Analytical Parametric Investigation of Low Pressure Ratio Fan Noise PDF eBook
Author
Publisher
Pages 124
Release 1973
Genre Airplanes
ISBN

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NASA Technical Memorandum

NASA Technical Memorandum
Title NASA Technical Memorandum PDF eBook
Author
Publisher
Pages 492
Release 1994
Genre Aeronautics
ISBN

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NASA Contractor Report

NASA Contractor Report
Title NASA Contractor Report PDF eBook
Author
Publisher
Pages 700
Release 1975
Genre Aeronautics
ISBN

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Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports
Title Scientific and Technical Aerospace Reports PDF eBook
Author
Publisher
Pages 518
Release 1993
Genre Aeronautics
ISBN

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NASA Technical Note

NASA Technical Note
Title NASA Technical Note PDF eBook
Author
Publisher
Pages 880
Release 1976
Genre Aeronautics
ISBN

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