Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Acoustic Performance Of The Geae Ups Research Fan In The Nasa Glenn 9 By 15 Foot Low Speed Wind Tunnel
Download Acoustic Performance Of The Geae Ups Research Fan In The Nasa Glenn 9 By 15 Foot Low Speed Wind Tunnel full books in PDF, epub, and Kindle. Read online Acoustic Performance Of The Geae Ups Research Fan In The Nasa Glenn 9 By 15 Foot Low Speed Wind Tunnel ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Acoustic Performance of the GEAE UPS Research Fan in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel by : National Aeronaut Administration (Nasa)
Download or read book Acoustic Performance of the GEAE UPS Research Fan in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel written by National Aeronaut Administration (Nasa) and published by Independently Published. This book was released on 2020-08-21 with total page 82 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 in 1994. The Universal Propulsion Simulator fan was designed and manufactured by General Electric Aircraft Engines, and included an active core, as well as bypass, flow paths. The fan was tested with several rotors featuring unswept, forward-swept and aft-swept designs of both metal and composite construction. Sideline acoustic data were taken with both hard and acoustically treated walls in the flow passages. The fan was tested within an airflow at a Mach number of 0.20, which is representative of aircraft takeoff/approach conditions. All rotors showed similar aerodynamic performance. However, the composite rotors typically showed higher noise levels than did corresponding metal rotors. Aft and forward rotor sweep showed at most modest reductions of transonic multiple pure tone levels. However, rotor sweep often introduced increased rotor-stator interaction tone levels. Broadband noise was typically higher for the composite rotors and also for the aft-swept metal rotor. Transonic MPT generation was reduced with increasing fan axis angle of attack (AOA); however, higher downstream noise levels did increase with AOA resulting in higher overall Effective Perceived Noise Level. Woodward, Richard P. and Hughes, Christopher E. Glenn Research Center NASA/TM-2012-217450, E-18180 WBS 561581.02.08.03.45.02.04
Book Synopsis Acoustic performance of the GEAE UPS research fan in the NASA Glenn 9- by 15-foot low-speed wind tunnel by : Richard P. Woodward
Download or read book Acoustic performance of the GEAE UPS research fan in the NASA Glenn 9- by 15-foot low-speed wind tunnel written by Richard P. Woodward and published by . This book was released on 2012 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Acoustic Performance of the Geae Ups Research Fan in the Nasa Glenn 9- by 15-Foot Low-Speed Wind Tunnel by : Nasa Technical Reports Server (Ntrs)
Download or read book Acoustic Performance of the Geae Ups Research Fan in the Nasa Glenn 9- by 15-Foot Low-Speed Wind Tunnel written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 86 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 in 1994. The Universal Propulsion Simulator fan was designed and manufactured by General Electric Aircraft Engines, and included an active core, as well as bypass, flow paths. The fan was tested with several rotors featuring unswept, forward-swept and aft-swept designs of both metal and composite construction. Sideline acoustic data were taken with both hard and acoustically treated walls in the flow passages. The fan was tested within an airflow at a Mach number of 0.20, which is representative of aircraft takeoff/approach conditions. All rotors showed similar aerodynamic performance. However, the composite rotors typically showed higher noise levels than did corresponding metal rotors. Aft and forward rotor sweep showed at most modest reductions of transonic multiple pure tone levels. However, rotor sweep often introduced increased rotor-stator interaction tone levels. Broadband noise was typically higher for the composite rotors and also for the aft-swept metal rotor. Transonic MPT generation was reduced with increasing fan axis angle of attack (AOA); however, higher downstream noise levels did increase with AOA resulting in higher overall Effective Perceived Noise Level.
Book Synopsis Acoustic Performance of an Advanced Model Turbofan in Three Aeroacoustic Test Facilities by : National Aeronaut Administration (Nasa)
Download or read book Acoustic Performance of an Advanced Model Turbofan in Three Aeroacoustic Test Facilities written by National Aeronaut Administration (Nasa) and published by . This book was released on 2020-08-11 with total page 64 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 NASA/TM-2012-217608, E-18189 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
Book Synopsis Acoustic Methods Used in the NASA Glenn 9-by 15-foot Low-speed Wind Tunnel by : Clifford A. Brown
Download or read book Acoustic Methods Used in the NASA Glenn 9-by 15-foot Low-speed Wind Tunnel written by Clifford A. Brown and published by . This book was released on 2018 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Acoustical Evaluation of the NASA Lewis 9 by 15 Foot Low Speed Wind Tunnel by : Milo D. Dahl
Download or read book Acoustical Evaluation of the NASA Lewis 9 by 15 Foot Low Speed Wind Tunnel written by Milo D. Dahl and published by . This book was released on 1992 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Acoustic Performance of an Advanced Model Turbofan in Three Aeroacoustic Test Facilities by : Nasa Technical Reports Server (Ntrs)
Download or read book Acoustic Performance of an Advanced Model Turbofan in Three Aeroacoustic Test Facilities written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 66 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.
Download or read book Green Aviation written by Emily S. Nelson and published by CRC Press. This book was released on 2018-06-12 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aircraft emissions currently account for ~3.5% of all greenhouse gas emissions. The number of passenger miles has increased by 5% annually despite 9/11, two wars and gloomy economic conditions. Since aircraft have no viable alternative to the internal combustion engine, improvements in aircraft efficiency and alternative fuel development become essential. This book comprehensively covers the relevant issues in green aviation. Environmental impacts, technology advances, public policy and economics are intricately linked to the pace of development that will be realized in the coming decades. Experts from NASA, industry and academia review current technology development in green aviation that will carry the industry through 2025 and beyond. This includes increased efficiency through better propulsion systems, reduced drag airframes, advanced materials and operational changes. Clean combustion and emission control of noise, exhaust gases and particulates are also addressed through combustor design and the use of alternative fuels. Economic imperatives from aircraft lifetime and maintenance logistics dictate the drive for "drop-in" fuels, blending jet-grade and biofuel. New certification standards for alternative fuels are outlined. Life Cycle Assessments are used to evaluate worldwide biofuel approaches, highlighting that there is no single rational approach for sustainable buildup. In fact, unless local conditions are considered, the use of biofuels can create a net increase in environmental impact as a result of biofuel manufacturing processes. Governmental experts evaluate current and future regulations and their impact on green aviation. Sustainable approaches to biofuel development are discussed for locations around the globe, including the US, EU, Brazil, China and India.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722155667 Total Pages :64 pages Book Rating :4.1/5 (556 download)
Book Synopsis Acoustical Evaluation of the NASA Lewis 9 by 15 Foot Low Speed Wind Tunnel by : National Aeronautics and Space Administration (NASA)
Download or read book Acoustical Evaluation of the NASA Lewis 9 by 15 Foot Low Speed Wind Tunnel written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The test section of the NASA Lewis 9- by 15-Foot Low Speed Wind Tunnel was acoustically treated to allow the measurement of acoustic sources located within the tunnel test section under simulated free field conditions. The treatment was designed for high sound absorption at frequencies above 250 Hz and to withstand tunnel airflow velocities up to 0.2 Mach. Evaluation tests with no tunnel airflow were conducted in the test section to assess the performance of the installed treatment. This performance would not be significantly affected by low speed airflow. Time delay spectrometry tests showed that interference ripples in the incident signal resulting from reflections occurring within the test section average from 1.7 dB to 3.2 dB wide over a 500 to 5150 Hz frequency range. Late reflections, from upstream and downstream of the test section, were found to be insignificant at the microphone measuring points. For acoustic sources with low directivity characteristics, decay with distance measurements in the test section showed that incident free field behavior can be measured on average with an accuracy of +/- 1.5 dB or better at source frequencies from 400 Hz to 10 kHz. The free field variations are typically much smaller with an omnidirectional source. Dahl, Milo D. and Woodward, Richard P. Glenn Research Center...
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721683918 Total Pages :24 pages Book Rating :4.6/5 (839 download)
Book Synopsis Noise Benefits of Increased Fan Bypass Nozzle Area by : National Aeronautics and Space Administration (NASA)
Download or read book Noise Benefits of Increased Fan Bypass Nozzle Area written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced model turbofan (typical of current engine technology) was tested in the NASA Glenn 9 by 15 Foot Low Speed Wind Tunnel (9-by 15-Foot LSWT) to explore far field acoustic effects of increased bypass nozzle area. This fan stage test was part of the NASA Glenn Fan Broadband Source Diagnostic Test, second entry (SDT2) which acquired aeroacoustic results over a range of test conditions. The baseline nozzle was sized to produce maximum stage performance for the engine at a high altitude, cruise point condition. However, the wind tunnel testing is conducted near sea level conditions. Therefore, in order to simulate and obtain performance at other aircraft operating conditions, two additional nozzles were designed and tested-one with a +5 percent increase in weight flow (+5.4 percent increase in nozzle area compared with the baseline nozzle), sized to simulate the performance at the stage design point conditions, and the other with a +7.5 percent increase in weight flow (+10.9 percent increase in nozzle area), sized for maximum weight flow with a fixed nozzle at sea level conditions. Measured acoustic benefits with increased nozzle area were very encouraging, showing overall sound power level (OAPWL) reductions of 2 or more dB while the stage thrust actually increased by several percentage points except fro the most open nozzle at takeoff rotor speed where stage performance decreased. These noise reduction benefits were seen to primarily affect broadband noise, and were evident throughout the range of measured sideline angles. Woodward, Richard P. and Hughes, Christopher E. Glenn Research Center NASA/TM-2004-213396, AIAA Paper 2005-1201, E-14899
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781726184670 Total Pages :34 pages Book Rating :4.1/5 (846 download)
Book Synopsis Aeroacoustic Analysis of Fan Noise Reduction with Increased Bypass Nozzle Area by : National Aeronautics and Space Administration (NASA)
Download or read book Aeroacoustic Analysis of Fan Noise Reduction with Increased Bypass Nozzle Area written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-27 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced model turbofan was tested in the NASA Glenn 9-by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) to explore far field acoustic effects of increased bypass nozzle area. This fan stage test was part of the NASA Glenn Fan Broadband Source Diagnostic Test, second entry (SDT2) which acquired aeroacoustic results over a range of test conditions. The baseline nozzle was sized to produce maximum stage performance at cruise condition. However, the wind tunnel testing is conducted near sea level condition. Therefore, in order to simulate and obtain performance at other operating conditions, two additional nozzles were designed and tested one with +5 percent increase in weight flow (+5.4 percent increase in nozzle area compared with the baseline nozzle), sized to simulate the performance at the stage design point (takeoff) condition, and the other with a +7.5 percent increase in weight flow (+10.9 percent increase in nozzle area) sized for maximum weight flow with a fixed nozzle at sea level condition. Measured acoustic benefits with increased nozzle area were very encouraging, showing overall sound power level (OAPWL) reductions of 2 or more dB while the stage thrust actually increased by 2 to 3 percent except for the most open nozzle at takeoff rotor speed where stage performance decreased. Effective perceived noise levels for a 1500 ft engine flyover and 3.35 scale factor showed a similar noise reduction of 2 or more EPNdB. Noise reductions, principally in the level of broadband noise, were observed everywhere in the far field. Laser Doppler Velocimetry measurements taken downstream of the rotor showed that the total turbulent velocity decreased with increasing nozzle flow, which may explain the reduced rotor broadband noise levels.Woodward, Richard P. and Hughes, Christopher E. and Podboy, Gary G.Glenn Research CenterAEROACOUSTICS; FAN BLADES; LOW SPEED WIND TUNNELS; NOZZLE FLOW; WIND TUNNEL TESTS; NOISE REDUCTION; AIRCRAFT ENGINES; BYPASSES; NOZZLE DESIGN; EFFECTIVE...
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781720522010 Total Pages :28 pages Book Rating :4.5/5 (22 download)
Book Synopsis Fan Noise Source Diagnostic Test by : National Aeronautics and Space Administration (NASA)
Download or read book Fan Noise Source Diagnostic Test written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-31 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aerodynamic performance of an isolated fan or rotor alone model was measured in the NASA Glenn Research Center 9- by 15- Foot Low Speed Wind Tunnel as part of the Fan Broadband Source Diagnostic Test conducted at NASA Glenn. The Source Diagnostic Test was conducted to identify the noise sources within a wind tunnel scale model of a turbofan engine and quantify their contribution to the overall system noise level. The fan was part of a 1/5th scale model representation of the bypass stage of a current technology turbofan engine. For the rotor alone testing, the fan and nacelle, including the inlet, external cowl, and fixed area fan exit nozzle, were modeled in the test hardware; the internal outlet guide vanes located behind the fan were removed. Without the outlet guide vanes, the velocity at the nozzle exit changes significantly, thereby affecting the fan performance. As part of the investigation, variations in the fan nozzle area were tested in order to match as closely as possible the rotor alone performance with the fan performance obtained with the outlet guide vanes installed. The fan operating performance was determined using fixed pressure/temperature combination rakes and the corrected weight flow. The performance results indicate that a suitable nozzle exit was achieved to be able to closely match the rotor alone and fan/outlet guide vane configuration performance on the sea level operating line. A small shift in the slope of the sea level operating line was measured, which resulted in a slightly higher rotor alone fan pressure ratio at take-off conditions, matched fan performance at cutback conditions, and a slightly lower rotor alone fan pressure ratio at approach conditions. However, the small differences in fan performance at all fan conditions were considered too small to affect the fan acoustic performance.Hughes, Christopher E. and Jeracki, Robert J. and Woodward, Richard P. and Miller, Christopher J.Glenn Research CenterAERODYNAMIC CHARACTERISTI
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721777457 Total Pages :34 pages Book Rating :4.7/5 (774 download)
Book Synopsis Flow Measurements and Multiple Pure Tone Noise from a Forward Swept Fan by : National Aeronautics and Space Administration (NASA)
Download or read book Flow Measurements and Multiple Pure Tone Noise from a Forward Swept Fan written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-24 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A forward-swept fan, designated the Quiet High Speed Fan (QHSF), was tested in the NASA Glenn 9- by 15-foot Low Speed Wind Tunnel to investigate its noise reduction relative to a baseline fan of the same aerodynamic performance. The objective of the Quiet High Speed Fan was a 6-dB reduction in the Effective Perceived Noise Level relative to the baseline fan at the takeoff condition. The intent of the Quiet High Speed Fan design was to provide both a multiple pure tone noise reduction from the forward sweep of the fan rotor and a rotor-stator interaction blade passing tone noise reduction from a leaned stator. The tunnel noise data indicted that the Quiet High Speed Fan was quieter than the baseline fan for a significant portion of the operating line and was 6 dB quieter near the takeoff condition. Although reductions in the multiple pure tones were observed, the vast majority of the EPNdB reduction was a result of the reduction in the blade passing tone and its harmonics. Laser Doppler Velocimetry (LDV) and shroud unsteady pressure measurement data were obtained upstream of the QHSF and baseline rotors to improve the understanding of the shocks which propagate upstream of the two fans when they are operated at high speeds. The flow phenomena that produce multiple pure tone noise is discussed and compared to measurements of the fan acoustic inlet modes and the far field noise signature of the fan. Weir, Donald S. and Podboy, Gary G. Glenn Research Center NASA/TM-2005-213413, AIAA Paper 2005-1200, E-14931
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781719381772 Total Pages :24 pages Book Rating :4.3/5 (817 download)
Book Synopsis Acoustic Performance of Novel Fan Noise Reduction Technologies for a High Bypass Model Turbofan at Simulated Flights Conditions by : National Aeronautics and Space Administration (NASA)
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
Book Synopsis Acoustic performance of two 1.83-meter-diameter fans designed for a wind-tunnel drive system by : Paul R. Soderman
Download or read book Acoustic performance of two 1.83-meter-diameter fans designed for a wind-tunnel drive system written by Paul R. Soderman and published by . This book was released on 1977 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721023172 Total Pages :32 pages Book Rating :4.0/5 (231 download)
Book Synopsis The Noise of a Forward Swept Fan by : National Aeronautics and Space Administration (NASA)
Download or read book The Noise of a Forward Swept Fan written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-11 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A forward swept fan, designated the Quiet High Speed Fan (QHSF), was tested in the NASA Glenn 9-by 15-foot Low Speed Wind Tunnel to investigate its noise reduction relative to a baseline fan of the same aerodynamic performance. The objective of the Quiet High Speed Fan was a 6 decibel reduction in the Effective Perceived Noise relative to the baseline fan at the takeoff condition. The intent of the Quiet High Speed Fan design was to provide both a multiple pure tone noise reduction from the forward sweep of the fan rotor and a rotor-stator interaction blade passing tone noise reduction from a leaned stator. The tunnel noise data indicted that the Quiet High Speed Fan was quieter than the baseline fan for a significant portion of the operating line and was 6 dB quieter near the takeoff condition. Although reductions in the multiple pure tones were observed, the vast majority of the EPNdB reduction was a result of the reduction in the blade passing tone and its harmonics. The baseline fan's blade passing tone was dominated by the rotor-strut interaction mechanism. The observed blade passing tone reduction could be the result of either the redesign of the Quiet High Speed Fan Rotor or the redesigned stator. The exact cause of this rotor-strut noise reduction, whether from the rotor or stator redesign, was not discernable from this experiment.Dittmar, James H. and Elliott, David M. and Fite, E. BrianGlenn Research CenterAERODYNAMIC NOISE; LOW SPEED WIND TUNNELS; FAN BLADES; AIRCRAFT DESIGN; AEROACOUSTICS; ROTOR STATOR INTERACTIONS; VANES; AIRCRAFT WAKES; SUPERSONIC SPEED; PROPELLER NOISE; STRUTS
Book Synopsis Fan Rig Noise Spectral Correction for Nasa 9'X 15' Low-Speed Wind Tunnel by : Nasa Technical Reports Server (Ntrs)
Download or read book Fan Rig Noise Spectral Correction for Nasa 9'X 15' Low-Speed Wind Tunnel written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-08 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aircraft engine noise research and development depends on the ability to study and predict the noise created by each engine component in isolation. Fan noise testing, however, requires a significant support system including a drive mechanism to turn the fan, a device to smooth the flow into the fan, and a stand to raise the fan off the ground each of which has the potential to create its own noise. A methodology was therefore developed to improve the data quality for the 9x15 Low Speed Wind Tunnel (LSWT) at the NASA Glenn Research Center that identifies three noise sources: fan noise, jet noise, and rig noise. The jet noise and rig noise was then measured by mounting a scale model of the 9x15 LSWT setup in a jet rig to simulate everything except the rotating machinery that characterizes fan noise. The data showed that the spectra measured in the LSWT has a strong rig noise component at frequencies as high as 3 kHz depending on the fan and speed. The jet noise was determined to be significantly lower than the rig noise. A mathematical model for the rig noise was then developed using a multi-dimensional least squares fit to the rig noise data. This allows the rig noise to be subtracted or removed, depending on the amplitude of the rig noise relative to the fan noise, at any given frequency, observer angle, or nozzle pressure ratio. The impact of isolating the fan noise with this method on spectra, overall power level (OAPWL), and Effective Perceived Noise Level (EPNL) is studied.
