Download or read book STATIC AND WIND TUNNEL AERO PERFORMANCE TESTS OF NASA AST SEPARATE FLOW NOZZLE NOISE REDUCTION CONFIGURATION FINAL REPORT NASA written by United States. National Aeronautics and Space Administration and published by . This book was released on 2002* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Static and Wind Tunnel Aero Performance Tests of NASA Ast Separate Flow Nozzle Noise Reduction Configurations written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-27 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of cold flow model tests to determine the static and wind tunnel performance of several NASA AST separate flow nozzle noise reduction configurations. The tests were conducted by Aero Systems Engineering, Inc., for NASA Glenn Research Center. The tests were performed in the Channels 14 and 6 static thrust stands and the Channel 10 transonic wind tunnel at the FluiDyne Aerodynamics Laboratory in Plymouth, Minnesota. Facility checkout tests were made using standard ASME long-radius metering nozzles. These tests demonstrated facility data accuracy at flow conditions similar to the model tests. Channel 14 static tests reported here consisted of 21 ASME nozzle facility checkout tests and 57 static model performance tests (including 22 at no charge). Fan nozzle pressure ratio varied from 1.4 to 2.0, and fan to core total pressure ratio varied from 1.0 to 1.19. Core to fan total temperature ratio was 1.0. Channel 10 wind tunnel tests consisted of 15 tests at Mach number 0.28 and 31 tests at Mach 0.8. The sting was checked out statically in Channel 6 before the wind tunnel tests. In the Channel 6 facility, 12 ASME nozzle data points were taken and 7 model data points were taken. In the wind tunnel, fan nozzle pressure ratio varied from 1.73 to 2.8, and fan to core total pressure ratio varied from 1.0 to 1.19. Core to fan total temperature ratio was 1.0. Test results include thrust coefficients, thrust vector angle, core and fan nozzle discharge coefficients, total pressure and temperature charging station profiles, and boat-tail static pressure distributions in the wind tunnel. Mikkelsen, Kevin L. and McDonald, Timothy J. and Saiyed, Naseem (Technical Monitor) Glenn Research Center NAS3-98021; RTOP 781-30-12...
Download or read book Advanced Subsonic Technology Ast Separate Flow High Bypass Ratio Nozzle Noise Reduction Program Test Report written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-20 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: NASA s model-scale nozzle noise tests show that it is possible to achieve a 3 EPNdB jet noise reduction with inwardfacing chevrons and flipper-tabs installed on the primary nozzle and fan nozzle chevrons. These chevrons and tabs are simple devices and are easy to be incorporated into existing short duct separate-flow nonmixed nozzle exhaust systems. However, these devices are expected to cause some small amount of thrust loss relative to the axisymmetric baseline nozzle system. Thus, it is important to have these devices further tested in a calibrated nozzle performance test facility to quantify the thrust performances of these devices. The choice of chevrons or tabs for jet noise suppression would most likely be based on the results of thrust loss performance tests to be conducted by Aero System Engineering (ASE) Inc. It is anticipated that the most promising concepts identified from this program will be validated in full scale engine tests at both Pratt & Whitney and Allied-Signal, under funding from NASA s Engine Validation of Noise Reduction Concepts (EVNRC) programs. This will bring the technology readiness level to the point where the jet noise suppression concepts could be incorporated with high confidence into either new or existing turbofan engines having short-duct, separate-flow nacelles. Low, John K. C. and Schweiger, Paul S. and Premo, John W. and Barber, Thomas J. and Saiyed, Naseem (Technical Monitor) Glenn Research Center NAS3-27727; WU 522-81-11...
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...
Download or read book Ast Critical Propulsion and Noise Reduction Technologies for Future Commercial Subsonic Engines written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-27 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the work performed by General Electric Aircraft Engines (GEAE) and Allison Engine Company (AEC) on NASA Contract NAS3-27720 AoI 14.3. The objective of this contract was to generate quality jet noise acoustic data for separate-flow nozzle models and to design and verify new jet-noise-reduction concepts over a range of simulated engine cycles and flight conditions. Five baseline axisymmetric separate-flow nozzle models having bypass ratios of five and eight with internal and external plugs and 11 different mixing-enhancer model nozzles (including chevrons, vortex-generator doublets, and a tongue mixer) were designed and tested in model scale. Using available core and fan nozzle hardware in various combinations, 28 GEAE/AEC separate-flow nozzle/mixing-enhancer configurations were acoustically evaluated in the NASA Glenn Research Center Aeroacoustic and Propulsion Laboratory. This report describes model nozzle features, facility and data acquisition/reduction procedures, the test matrix, and measured acoustic data analyses. A number of tested core and fan mixing enhancer devices and combinations of devices gave significant jet noise reduction relative to separate-flow baseline nozzles. Inward-flip and alternating-flip core chevrons combined with a straight-chevron fan nozzle exceeded the NASA stretch goal of 3 EPNdB jet noise reduction at typical sideline certification conditions. Janardan, B. A. and Hoff, G. E. and Barter, J. W. and Martens, S. and Gliebe, P. R. and Mengle, V. and Dalton, W. N. and Saiyed, Naseem (Technical Monitor) Glenn Research Center NAS3-27720; RTOP 522-81-11...
Download or read book Aeroacoustics of Flight Vehicles written by Harvey H. Hubbard and published by . This book was released on 1991 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Langley Low Speed Aeroacoustic Wind Tunnel written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-03 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NASA Langley Research Center Low Speed Aeroacoustic Wind Tunnel is a premier facility for model-scale testing of jet noise reduction concepts at realistic flow conditions. However, flow inside the open jet test section is less than optimum. A Construction of Facilities project, scheduled for FY 05, will replace the flow collector with a new design intended to reduce recirculation in the open jet test section. The reduction of recirculation will reduce background noise levels measured by a microphone array impinged by the recirculation flow and will improve flow characteristics in the open jet tunnel flow. In order to assess the degree to which this modification is successful, background noise levels and tunnel flow are documented, in order to establish a baseline, in this report.Booth, Earl R., Jr. and Henderson, Brenda S.Langley Research CenterAEROACOUSTICS; LOW SPEED WIND TUNNELS; WIND TUNNEL TESTS; JET AIRCRAFT NOISE; NASA PROGRAMS; BACKGROUND NOISE; TEST FACILITIES; NOISE INTENSITY; NOISE REDUCTION; FLOW CHARACTERISTICS; MICROPHONES; DATA PROCESSING; ACOUSTIC MEASUREMENT; JET FLOW
Download or read book Results of Aero Acoustic Tests and Analytical Studies of a Two Dimensional Eight Lobe Mixer Ejector Exhaust Nozzle at Takeoff Conditions written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-27 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hot flow aero-acoustic tests were conducted with Pratt & Whitney's High-Speed Civil Transport (HSCT) Mixer-Ejector Exhaust Nozzles by General Electric Aircraft Engines (GEAE) in the GEAE Anechoic Freejet Noise Facility (Cell 41) located in Evendale, Ohio. The tests evaluated the impact of various geometric and design parameters on the noise generated by a two-dimensional (2-D) shrouded, 8-lobed, mixer-ejector exhaust nozzle. The shrouded mixer-ejector provides noise suppression by mixing relatively low energy ambient air with the hot, high-speed primary exhaust jet. Additional attenuation was obtained by lining the shroud internal walls with acoustic panels, which absorb acoustic energy generated during the mixing process. Two mixer designs were investigated, the high mixing "vortical" and aligned flow "axial", along with variations in the shroud internal mixing area ratios and shroud length. The shrouds were tested as hardwall or lined with acoustic panels packed with a bulk absorber. A total of 21 model configurations at 1:11.47 scale were tested. The models were tested over a range of primary nozzle pressure ratios and primary exhaust temperatures representative of typical HSCT aero thermodynamic cycles. Static as well as flight simulated data were acquired during testing. A round convergent unshrouded nozzle was tested to provide an acoustic baseline for comparison to the test configurations. Comparisons were made to previous test results obtained with this hardware at NASA Glenn's 9- by 15-foot low-speed wind tunnel (LSWT). Laser velocimetry was used to investigate external as well as ejector internal velocity profiles for comparison to computational predictions. Ejector interior wall static pressure data were also obtained. A significant reduction in exhaust system noise was demonstrated with the 2-D shrouded nozzle designs. Harrington, Douglas (Technical Monitor) and Schweiger, P. and Stern, A. and Gamble, E. and Barber, T. and Chiappe...
Download or read book Static and Wind Tunnel Model Tests for the Development of Externally Blown Flap Noise Reduction Techniques written by A. P. Pennock and published by . This book was released on 1975 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 2002 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Model Scale Aerodynamic Performance Testing of Proposed Modifications to the NASA Langley Low Speed Aeroacoustic Wind Tunnel 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 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tests were performed on a 1/20th-scale model of the Low Speed Aeroacoustic Wind Tunnel to determine the performance effects of insertion of acoustic baffles in the tunnel inlet, replacement of the existing collector with a new collector design in the open jet test section, and addition of flow splitters to the acoustic baffle section downstream of the test section. As expected, the inlet baffles caused a reduction in facility performance. About half of the performance loss was recovered by addition the flow splitters to the downstream baffles. All collectors tested reduced facility performance. However, test chamber recirculation flow was reduced by the new collector designs and shielding of some of the microphones was reduced owing to the smaller size of the new collector. Overall performance loss in the facility is expected to be a 5 percent top flow speed reduction, but the facility will meet OSHA limits for external noise levels and recirculation in the test section will be reduced. Booth, Earl R., Jr. and Coston, Calvin W., Jr. Langley Research Center NASA/TM-2005-213534, L-19093
Download or read book Nasa Langley Low Speed Aeroacoustic Wind Tunnel written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NASA Langley Research Center Low Speed Aeroacoustic Wind Tunnel is a premier facility for model-scale testing of jet noise reduction concepts at realistic flow conditions. However, flow inside the open jet test section is less than optimum. A Construction of Facilities project, scheduled for FY 05, will replace the flow collector with a new design intended to reduce recirculation in the open jet test section. The reduction of recirculation will reduce background noise levels measured by a microphone array impinged by the recirculation flow and will improve flow characteristics in the open jet tunnel flow. In order to assess the degree to which this modification is successful, background noise levels and tunnel flow are documented, in order to establish a baseline, in this report.
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
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
Download or read book High speed Wind Tunnels written by Luigi Crocco and published by . This book was released on 1946 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance assumed in recent times by experimental supersonic wind tunnels, as well as the power required, has brought about the need for a study which would permit a comparison of the types tested and the principal theoretical plans.
Download or read book Comparison of Options for Reduction of Noise in the Test Section of the NASA Langley 4x7m Wind Tunnel Including Reduction of Nozzle Area written by and published by . This book was released on 1984 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
