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  • 1
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    Acoustic Characterization of Compact Jet Engine Simulator Units (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Two dual-stream, heated jet, Compact Jet Engine Simulator (CJES) units are designed for wind tunnel acoustic experiments involving a Hybrid Wing Body (HWB) vehicle. The newly fabricated CJES units are characterized with a series of acoustic and flowfield investigations to ensure successful operation with minimal rig noise. To limit simulator size, consistent with a 5.8% HWB model, the CJES units adapt Ultra Compact Combustor (UCC) technology developed at the Air Force Research Laboratory. Stable and controllable operation of the combustor is demonstrated using passive swirl air injection and backpressuring of the combustion chamber. Combustion instability tones are eliminated using nonuniform flow conditioners in conjunction with upstream screens. Through proper flow conditioning, rig noise is reduced by more than 20 dB over a broad spectral range, but it is not completely eliminated at high frequencies. The low-noise chevron nozzle concept designed for the HWB test shows expected acoustic benefits when installed on the CJES unit, and consistency between CJES units is shown to be within 0.5 dB OASPL.
    Keywords: Acoustics
    Type: NF1676L-15514 , AIAA Paper 2013-2035 , 19th AIAA/CEAS Aeroacoustics Conference; May 27, 2013 - May 29, 2013; Berlin; Germany
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Aerodynamic Performance and Acoustic Measurements of a High-Lift Propeller in an Isolated Configuration (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: A series of aerodynamic performance and acoustic measurements has been made on a high-lift propeller intended for utilization on a distributed electric propulsion (DEP) aircraft. Tests were performed in the NASA Langley Low Speed Aeroacoustic Wind Tunnel (LSAWT), which has recently undergone a capability enhancement for the testing of small propellers/rotors and small unmanned aircraft system (UAS) platforms. The objectives of this testing campaign are two-fold: first to demonstrate the facility capabilities for performing small propeller aeroacoustic testing, and second to compare experimental measurements with computational fluid dynamic (CFD) predictions and CFD-based acoustic predictions of the tested propeller configurations for tool development and validation purposes.
    Keywords: Acoustics
    Type: NF1676L-28547 , AIAA Aviation and Aeronautics Forum (Aviation 2018); Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Flame Holder System (2013)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: A flame holder system includes a modified torch body and a ceramic flame holder. Catch pin(s) are coupled to and extend radially out from the torch body. The ceramic flame holder has groove(s) formed in its inner wall that correspond in number and positioning to the catch pin(s). Each groove starts at one end of the flame holder and can be shaped to define at least two 90.degree.turns. Each groove is sized to receive one catch pin therein when the flame holder is fitted over the end of the torch body. The flame holder is then manipulated until the catch pin(s) butt up against the end of the groove(s).
    Keywords: Mechanical Engineering
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Flame Holder System (2018)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: A flame holder system includes a modified torch body and a ceramic flame holder. Catch pin(s) are coupled to and extend radially out from the torch body. The ceramic flame holder has groove(s) formed in its inner wall that correspond in number and positioning to the catch pin(s). Each groove starts at one end of the flame holder and is can be shaped to define at least two 90 degree elbows. Each groove is sized to receive one catch pin therein when the flame holder is fitted over the end of the torch body. The flame holder is then manipulated until the catch pin(s) butt up against the end of the groove(s).
    Keywords: Aircraft Propulsion and Power
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Investigation of Flow Conditioners for Compact Jet Engine Simulator Rig Noise Reduction (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The design requirements for two new Compact Jet Engine Simulator (CJES) units for upcoming wind tunnel testing lead to the distinct possibility of rig noise contamination. The acoustic and aerodynamic properties of several flow conditioner devices are investigated over a range of operating conditions relevant to the CJES units to mitigate the risk of rig noise. An impinging jet broadband noise source is placed in the upstream plenum of the test facility permitting measurements of not only flow conditioner self-noise, but also noise attenuation characteristics. Several perforated plate and honeycomb samples of high porosity show minimal self-noise but also minimal attenuation capability. Conversely, low porosity perforated plate and sintered wire mesh conditioners exhibit noticeable attenuation but also unacceptable self-noise. One fine wire mesh sample (DP450661) shows minimal selfnoise and reasonable attenuation, particularly when combined in series with a 15.6 percent open area (POA) perforated plate upstream. This configuration is the preferred flow conditioner system for the CJES, providing up to 20 dB of broadband attenuation capability with minimal self-noise.
    Keywords: Aerodynamics
    Type: NF1676L-11648 , 17th AIAA/CEAS Aeroacoustics Conference; Jun 06, 2011 - Jun 08, 2011; Portland, OR; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Hybrid Wing Body Aircraft Acoustic Test Preparations and Facility Upgrades (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: NASA is investigating the potential of acoustic shielding as a means to reduce the noise footprint at airport communities. A subsonic transport aircraft and Langley's 14- by 22-foot Subsonic Wind Tunnel were chosen to test the proposed "low noise" technology. The present experiment studies the basic components of propulsion-airframe shielding in a representative flow regime. To this end, a 5.8-percent scale hybrid wing body model was built with dual state-of-the-art engine noise simulators. The results will provide benchmark shielding data and key hybrid wing body aircraft noise data. The test matrix for the experiment contains both aerodynamic and acoustic test configurations, broadband turbomachinery and hot jet engine noise simulators, and various airframe configurations which include landing gear, cruise and drooped wing leading edges, trailing edge elevons and vertical tail options. To aid in this study, two major facility upgrades have occurred. First, a propane delivery system has been installed to provide the acoustic characteristics with realistic temperature conditions for a hot gas engine; and second, a traversing microphone array and side towers have been added to gain full spectral and directivity noise characteristics.
    Keywords: Acoustics
    Type: NF1676L-15662 , AIAA Aerodynamic Measurement Technology, Ground Testing, and Flight Testing Conference; Jun 24, 2013 - Jun 27, 2013; San Diego, CA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
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    Small Propeller and Rotor Testing Capabilities of the NASA Langley Low Speed Aeroacoustic Wind Tunnel (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Low Speed Aeroacoustic Wind Tunnel (LSAWT) at NASA Langley Research Center has recently undergone a configuration change. This change incorporates an inlet nozzle extension meant to serve the dual purposes of achieving lower free-stream velocities as well as a larger core flow region. The LSAWT, part of the NASA Langley Jet Noise Laboratory, had historically been utilized to simulate realistic forward flight conditions of commercial and military aircraft engines in an anechoic environment. The facility was modified starting in 2016 in order to expand its capabilities for the aerodynamic and acoustic testing of small propeller and unmanned aircraft system (UAS) rotor configurations. This paper describes the modifications made to the facility, its current aerodynamic and acoustic capabilities, the propeller and UAS rotor-vehicle configurations to be tested, and some preliminary predictions and experimental data for isolated propeller and UAS rotor con figurations, respectively. Isolated propeller simulations have been performed spanning a range of advance ratios to identify the theoretical propeller operational limits of the LSAWT. Performance and acoustic measurements of an isolated UAS rotor in hover conditions are found to compare favorably with previously measured data in an anechoic chamber and blade element-based acoustic predictions.
    Keywords: Acoustics; Aerodynamics
    Type: NF1676L-25691 , AIAA Aviation 2017; Jun 05, 2017 - Jun 09, 2017; Denver, CO; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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