Acoustic Performance Of Novel Fan Noise Reduction Technologies For A High Bypass Model Turbofan At Simulated Flight Conditions

Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781719381772
Total Pages : 24 pages
Book Rating : 4.71/5 ( download)

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Download or read book Acoustic Performance of Novel Fan Noise Reduction Technologies for a High Bypass Model Turbofan at Simulated Flights Conditions written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two novel fan noise reduction technologies, over the rotor acoustic treatment and soft stator vane technologies, were tested in an ultra-high bypass ratio turbofan model in the NASA Glenn Research Center s 9- by 15-Foot Low-Speed Wind Tunnel. The performance of these technologies was compared to that of the baseline fan configuration, which did not have these technologies. Sideline acoustic data and hot film flow data were acquired and are used to determine the effectiveness of the various treatments. The material used for the over the rotor treatment was foam metal and two different types were used. The soft stator vanes had several internal cavities tuned to target certain frequencies. In order to accommodate the cavities it was necessary to use a cut-on stator to demonstrate the soft vane concept. Elliott, David M. and Woodward, Richard P. and Podboy, Gary G. Glenn Research Center ACOUSTIC PROPERTIES; AERODYNAMIC NOISE; TURBOFANS; NOISE REDUCTION; BYPASS RATIO; WIND TUNNELS; FAN BLADES; VANES

Author : National Aeronautics and Space Administration (NASA)
Publisher :
ISBN 13 : 9781466499126
Total Pages : 28 pages
Book Rating : 4.25/5 ( download)

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Download or read book Acoustic Performance of Novel Fan Noise Reduction written by National Aeronautics and Space Administration (NASA) and published by . This book was released on 2010-11-01 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two novel fan noise reduction technologies, over the rotor acoustic treatment and soft stator vane technologies, were tested in an ultra-high bypass ratio turbofan model in the NASA Glenn Research Center's 9- by 15-Foot Low-Speed Wind Tunnel. The performance of these technologies was compared to that of the baseline fan configuration, which did not have these technologies. Sideline acoustic data and hot film flow data were acquired and are used to determine the effectiveness of the various treatments. The material used for the over the rotor treatment was foam metal and two different types were used. The soft stator vanes had several internal cavities tuned to target certain frequencies. In order to accommodate the cavities it was necessary to use a cut-on stator to demonstrate the soft vane concept.

Author : David M. Elliott
Publisher :
ISBN 13 :
Total Pages : 20 pages
Book Rating : 4.30/5 ( download)

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Download or read book Acoustic Performance of Novel Fan Noise Reduction Technologies for a High Bypass Model Turbofan at Simulated Flight Conditions written by David M. Elliott and published by . This book was released on 2010 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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ISBN 13 :
Total Pages : 1280 pages
Book Rating : 4.21/5 ( download)

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Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1980 with total page 1280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781719395397
Total Pages : 40 pages
Book Rating : 4.9X/5 ( download)

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Download or read book The Effect of Bypass Nozzle Exit Area on Fan Aerodynamic Performance and Noise in a Model Turbofan Simulator written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of effective new technologies to reduce aircraft propulsion noise is dependent on identifying and understanding the noise sources and noise generation mechanisms in the modern turbofan engine, as well as determining their contribution to the overall aircraft noise signature. Therefore, a comprehensive aeroacoustic wind tunnel test program was conducted called the Fan Broadband Source Diagnostic Test as part of the NASA Quiet Aircraft Technology program. The test was performed in the anechoic NASA Glenn 9- by 15-Foot Low Speed Wind Tunnel using a 1/5 scale model turbofan simulator which represented a current generation, medium pressure ratio, high bypass turbofan aircraft engine. The investigation focused on simulating in model scale only the bypass section of the turbofan engine. The test objectives were to: identify the noise sources within the model and determine their noise level; investigate several component design technologies by determining their impact on the aerodynamic and acoustic performance of the fan stage; and conduct detailed flow diagnostics within the fan flow field to characterize the physics of the noise generation mechanisms in a turbofan model. This report discusses results obtained for one aspect of the Source Diagnostic Test that investigated the effect of the bypass or fan nozzle exit area on the bypass stage aerodynamic performance, specifically the fan and outlet guide vanes or stators, as well as the farfield acoustic noise level. The aerodynamic performance, farfield acoustics, and Laser Doppler Velocimeter flow diagnostic results are presented for the fan and four different fixed-area bypass nozzle configurations. The nozzles simulated fixed engine operating lines and encompassed the fan stage operating envelope from near stall to cruise. One nozzle was selected as a baseline reference, representing the nozzle area which would achieve the design point operating conditions and fan stage performance. The total area change from the smallest to the largest nozzle was 12.9 percent of the baseline nozzle area. The results will show that there are significant changes in aerodynamic performance and farfield acoustics as the fan nozzle area is increased. The weight flow through the fan model increased between 7 and 9 percent, the fan and stage pressure dropped between 8 and 10 percent, and the adiabatic efficiency increased between 2 and 3 percent--the magnitude of the change dependent on the fan speed. Results from force balance measurements of fan and outlet guide vane thrust will show that as the nozzle exit area is increased the combined thrust of the fan and outlet guide vanes together also increases, between 2 and 3.5 percent, mainly due to the increase in lift from the outlet guide vanes. In terms of farfield acoustics, the overall sound power level produced by the fan stage dropped nearly linearly between 1 dB at takeoff condition and 3.5 dB at approach condition, mainly due to a decrease in the broadband n

Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781719500616
Total Pages : 60 pages
Book Rating : 4.14/5 ( download)

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Download or read book Acoustic Performance of an Advanced Model Turbofan in Three Aeroacoustic Test Facilities written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: A model advanced turbofan was acoustically tested in the NASA Glenn 9- by 15-Foot-Low-Speed Wind Tunnel (LSWT), and in two other aeroacoustic facilities. The Universal Propulsion Simulator (UPS) fan was designed and manufactured by the General Electric Aircraft Engines (GEAE) Company, and featured active core, as well as bypass, flow paths. The reference test configurations were with the metal, M4, rotor with hardwall and treated bypass flow ducts. The UPS fan was tested within an airflow at a Mach number of 0.20 (limited flow data were also acquired at a Mach number of 0.25) which is representative of aircraft takeoff and approach conditions. Comparisons were made between data acquired within the airflow (9x15 LSWT and German-Dutch Wind Tunnel (DNW)) and outside of a free jet (Boeing Low Speed Aero acoustic Facility (LSAF) and DNW). Sideline data were acquired on an 89-in. (nominal 4 fan diameters) sideline using the same microphone assembly and holder in the 9x15 LSWT and DNW facilities. These data showed good agreement for similar UPS operating conditions and configurations. Distortion of fan spectra tonal content through a free jet shear layer was documented, suggesting that in-flow acoustic measurements are required for comprehensive fan noise diagnostics. However, there was good agreement for overall sound power level (PWL) fan noise measurements made both within and outside of the test facility airflow. Woodward, Richard P. and Hughes, Christopher E. Glenn Research Center ACOUSTIC MEASUREMENT; AEROACOUSTICS; LOW SPEED WIND TUNNELS; TEST FACILITIES; TURBOFANS; WIND TUNNEL TESTS; AIRCRAFT MODELS; SIMULATORS; NOISE REDUCTION; SHEAR LAYERS; FREE JETS; FAN BLADES; AIR FLOW

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ISBN 13 :
Total Pages : 310 pages
Book Rating : 4.25/5 ( download)

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Download or read book NASA Technical Memorandum written by and published by . This book was released on 1982 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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ISBN 13 :
Total Pages : 580 pages
Book Rating : 4.67/5 ( download)

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Download or read book Aeronautical Engineering written by and published by . This book was released on 1971 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA)

Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781720373155
Total Pages : 38 pages
Book Rating : 4.59/5 ( download)

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Download or read book Aerodynamic Performance of Scale-Model Turbofan Outlet Guide Vanes Designed for Low Noise written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-30 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of effective new technologies to reduce aircraft propulsion noise is dependent on an understanding of the noise sources and noise generation mechanisms in the modern turbofan engine. In order to more fully understand the physics of noise in a turbofan engine, a comprehensive aeroacoustic wind tunnel test programs was conducted called the 'Source Diagnostic Test.' The text was cooperative effort between NASA and General Electric Aircraft Engines, as part of the NASA Advanced Subsonic Technology Noise Reduction Program. A 1/5-scale model simulator representing the bypass stage of a current technology high bypass ratio turbofan engine was used in the test. The test article consisted of the bypass fan and outlet guide vanes in a flight-type nacelle. The fan used was a medium pressure ratio design with 22 individual, wide chord blades. Three outlet guide vane design configurations were investigated, representing a 54-vane radial Baseline configuration, a 26-vane radial, wide chord Low Count configuration and a 26-vane, wide chord Low Noise configuration with 30 deg of aft sweep. The test was conducted in the NASA Glenn Research Center 9 by 15-Foot Low Speed Wind Tunnel at velocities simulating the takeoff and approach phases of the aircraft flight envelope. The Source Diagnostic Test had several acoustic and aerodynamic technical objectives: (1) establish the performance of a scale model fan selected to represent the current technology turbofan product; (2) assess the performance of the fan stage with each of the three distinct outlet guide vane designs; (3) determine the effect of the outlet guide vane configuration on the fan baseline performance; and (4) conduct detailed flowfield diagnostic surveys, both acoustic and aerodynamic, to characterize and understand the noise generation mechanisms in a turbofan engine. This paper addresses the fan and stage aerodynamic performance results from the Source Diagnostic Test.Hughes, Christopher E.Glenn Research Cente

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ISBN 13 :
Total Pages : 68 pages
Book Rating : 4.93/5 ( download)

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Download or read book Developmental Design, Fabrication, and Test of Acoustic Suppressors for Fans of High Bypass Turbofan Engines written by and published by . This book was released on 1974 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analysis procedure was developed for design of acoustically treated nacelles for high bypass turbofan engines. The plan was applied to the conceptual design of a nacelle for the quiet engine typical of a 707/DC-8 airplane installation. The resultant design was modified to a test nacelle design for the NASA Lewis quiet fan. The acoustic design goal was a 10 db reduction in effective perceived fan noise levels during takoff and approach. Detailed nacelle designs were subsequently developed for both the quiet engine and the quiet fan. The acoustic design goal for each nacelle was 15 db reductions in perceived fan noise levels from the inlet and fan duct. Acoustically treated nacelles were fabricated for the quiet engine and quiet fan for testing. Performance of selected inlet and fan duct lining configurations was experimentally evaluated in a flow duct. Results of the tests show that the linings perform as designed.