Download or read book Advanced Noise Control Fan Aerodynamic Performance written by Richard F. Bozak and published by BiblioGov. This book was released on 2013-07 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advanced Noise Control Fan at the NASA Glenn Research Center is used to experimentally analyze fan generated acoustics. In order to determine how a proposed noise reduction concept affects fan performance, flow measurements can be used to compute mass flow. Since tedious flow mapping is required to obtain an accurate mass flow, an equation was developed to correlate the mass flow to inlet lip wall static pressure measurements. Once this correlation is obtained, the mass flow for future configurations can be obtained from the nonintrusive wall static pressures. Once the mass flow is known, the thrust and fan performance can be evaluated. This correlation enables fan acoustics and performance to be obtained simultaneously without disturbing the flow.
Download or read book Advanced Noise Control Fan Aerodynamic Performance written by Richard F. Bozak (Jr) and published by . This book was released on 2009 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of two advanced noise reduction technologies on the aerodynamic performance of an ultra high bypass ratio fan written by and published by . This book was released on 2013 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustic and Aerodynamic Performance of a 6 foot diameter Fan for Turbofan Engines written by Edward J. Rice and published by . This book was released on 1971 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustic and Aerodynamic Performance of a 6 foot diameter Fan for Turbofan Engines written by Arthur W. Goldstein and published by . This book was released on 1970 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low noise turbofan engine without aerodynamic blade loading.
Download or read book Forward Acoustic Performance of a Model Turbofan Designed for a High Specific Flow QF 14 written by James G. Lucas and published by . This book was released on 1982 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Forward Acoustic Performance of a Model Turbofan Designed for a High Specific Flow QF 14 written by and published by . This book was released on 1982 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Forward Velocity Effects on Fan Noise and the Suppression Characteristics of Advanced Inlets as Measured in the NASA Ames 40 by 80 Foot Wind Tunnel written by and published by . This book was released on 1980 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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
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
Download or read book Acoustic and Aerodynamic Performance of 1 83 meter 6 ft Diameter 1 25 pressure ratio Fan QF 8 written by Richard P. Woodward and published by . This book was released on 1976 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Report of Fan Performance from Duct Rake Instrumentation on 1 294 Pressure Ratio 806 Ft sec Tip Speed Turbofan Simulator Models written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-15 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large scale model representative of an advanced ducted propulsor-type, low-noise, very high bypass ratio turbofan engine was tested for acoustics, aerodynamic performance, and off-design operability in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel. The test was part of NASA s Advanced Subsonic Technology Noise Reduction Program. The low tip speed fan, nacelle, and un-powered core passage were simulated. As might be expected, the effect of stall management casing treatment was a performance penalty. Reducing the recirculating flow at the fan tip reduced the penalty while still providing sufficient stall margin. Two fans were tested with the same aerodynamic design; one with graphite composite material, and the other with solid titanium. There were surprising performance differences between the two fans, though both blades showed some indication of transitional flow near the tips. Though the pressure and temperature ratios were low for this fan design, the techniques used to improve thermocouple measurement accuracy gave repeatable data with adiabatic efficiencies agreeing within 1 percent. The measured fan adiabatic efficiency at simulated takeoff conditions was 93.7 percent and matched the design intent. Jeracki, Robert J. Glenn Research Center WBS 22-781-30-50
Download or read book Forward Acoustic Performance of a Shock swallowing High tip speed Fan QF 13 written by James G. Lucas and published by . This book was released on 1980 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Noise Source Analysis and Control for Small Axial Flow Fans written by Chen Wang and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Noise Source Analysis and Control for Small Axial-flow Fans" by Chen, Wang, 王晨, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Fan noise is always an important topic in applications ranging from small cooling fans for computers, transport vehicles and machinery, and building ventilation fans, to large compressors and turbo-engine fans in aircraft. When air flow with higher pressure or larger flow rate is needed in some operating conditions, two fans in series or a contra-rotating fan is often adopted. The purpose of this project is to conduct the noise source analysis for two identical small axial-flow cooling fans and a newly designed small axial-flow contra-rotating fan (both about 120 mm in diameter), and to explore some passive methods to reduce the more complex radiated noise, compared with that encountered in a conventional single fan. For two fans in series, a technique of synchronous averaging with time-base stretching is used to decompose the raw sound signals into various noise source components. Acoustic directivity measurements are conducted for two operating conditions: free space and its usual working condition; each condition with two different configurations: free (unobstructed) inlet and distorted inlet by a flat plate covering part of inlet area. For both operating conditions, the rotary noise from the downstream fan dominates over that from the upstream fan for unobstructed inlet while the dominance by the downstream fan is reversed with distorted inlet. The total noise, total broadband noise and rotary noise radiated by the upstream fan all increase gradually with decreased plate-fan spacing. However, the rotary noise radiated by downstream fan is hardly affected by the obstacle plate, whatever the plate-fan spacing is. The flow straightener between the two fans contributes to considerable improvement of aerodynamic performance for free inlet case, while it has a limited role in remedying the severe inlet distortion when placed in front of the upstream fan. From the derived formula of acoustic spectrum from rotor blade forces resulting from the viscous and potential wakes of the upstream counter-rotating blade row impinging in the downstream one, two obvious mechanisms for interaction noise reduction can be easily found, which are either to increase the order of the Bessel function of the first kind, or to reduce the interaction fluctuating forces which can be realized by reducing the magnitude of the wake centerline velocity deficit or broaden the wake width. Several passive methods for reducing the aerodynamic interaction noise of a newly designed small axial-flow contra-rotating fan are explored. These methods include: (1) Perforated trailing edge for the upstream rotor and perforated leading edge for the downstream rotor; (2) Slitted trailing edge serration for the upstream rotor; (3) Chordwise perforated leading edge of the downstream rotor. Up to 5-7 dB overall noise reduction at all directions is achieved through the first two methods compared under the same aerodynamic output. Only 1.3 dB of acoustic benefit is achieved by the third method, but it hardly causes any adverse impact on the aerodynamic performance. The findings are useful and helpful in designing a quiet coaxial fan (two/multiple-stage or contra-rotating) and adopting an appropriate approach for noise mitigation. Subjects: Fans (Machinery) Noise control
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 Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 80 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 ACOUSTIC PROPERTIES; NOISE INTENSITY; AERODYNAMIC CHARACTERISTICS; MACH NUMBER; ANGLE OF ATTACK; AIR FLOW; WIND TUNNEL MODELS; WIND TUNNEL TESTS
Download or read book Acoustic and aerodynamic performance of a 1 5 pressure ratio 1 83 meter 6 ft diameter fan stage for turbofan engines QF 2 written by Richard P. Woodward and published by . This book was released on 1977 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
