Acoustic Characterization of Compact Jet Engine Simulator Units

Doty, Michael J.; Haskin, Henry H.

doi:10.2514/6.2013-2035

Cited by 4 publications

(5 citation statements)

References 14 publications

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“…Nonetheless, the combustion and rig noise challenges that accompany such small jet engine simulators require careful attention to the selection and placement of flow conditioners within the CJES units as further described in previous work. 4 Two sets of convergent core and fan nozzles are available for testing with each CJES unit-one set is axisymmetric while the other set includes an essentially uniform core chevron nozzle and an asymmetric fan chevron nozzle. The axisymmetric nozzle set provides a useful database of a conventional nozzle system applied to the HWB configuration.…”

Section: Cjes Unitsmentioning

confidence: 99%

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Jet noise shielding provided by a hybrid wing body aircraft

Doty

Brooks

Burley

et al. 2018

International Journal of Aeroacoustics

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One approach toward achieving NASA's aggressive N+2 noise goal of 42 EPNdB cumulative margin below Stage 4 is through the use of novel vehicle configurations like the hybrid wing body. Jet noise measurements from a hybrid wing body acoustic test in the NASA Langley 14-by 22-Foot Subsonic Tunnel are described. Two dual-stream, heated Compact Jet Engine Simulator units are mounted underneath the inverted hybrid wing body model on a traversable support to permit measurement of varying levels of shielding provided by the fuselage. Both an axisymmetric and low noise chevron nozzle set are investigated in the context of shielding. The unshielded chevron nozzle set shows 1-2 dB of source noise reduction (relative to the unshielded axisymmetric nozzle set) with some penalties at higher frequencies. Shielding of the axisymmetric nozzles shows up to 6.5 dB of reduction at high frequency. The combination of shielding and low noise chevrons shows benefits beyond the expected additive benefits of the two, up to 10 dB, due to the effective migration of the jet source peak noise location upstream for increased shielding effectiveness. Jet noise source maps from phased array results processed with the deconvolution approach for the mapping of acoustic sources algorithm reinforce these observations.

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Section: Cjes Unitsmentioning

confidence: 99%

“…Furthermore, minimizing rig noise, which can be prevalent for such a compact design, was an important requirement. Recent investigations 3,4 document the efforts behind the design and qualification of the CJES units prior to the HWB acoustic test.…”

Section: Introductionmentioning

confidence: 99%

Jet noise shielding provided by a hybrid wing body aircraft

Doty

Brooks

Burley

et al. 2018

International Journal of Aeroacoustics

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“…The UCC uses centrifugal loading to reduce combustion volume and thus reduce the overall length of the engine simulators. Nonetheless, the combustion and rig noise challenges that accompany such small jet engine simulators require careful attention to the selection and placement of flow conditioners within the CJES units as further described in previous work 4 .…”

Section: Cjes Unitsmentioning

confidence: 99%

Jet Noise Shielding Provided by a Hybrid Wing Body Aircraft

Doty

Brooks

Burley

et al. 2014

20th AIAA/CEAS Aeroacoustics Conference

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One approach toward achieving NASA's aggressive N+2 noise goal of 42 EPNdB cumulative margin below Stage 4 is through the use of novel vehicle configurations like the Hybrid Wing Body (HWB). Jet noise measurements from an HWB acoustic test in the NASA Langley 14-by 22-Foot Subsonic Tunnel are described. Two dual-stream, heated Compact Jet Engine Simulator (CJES) units are mounted underneath the inverted HWB model on a traversable support to permit measurement of varying levels of shielding provided by the fuselage. Both an axisymmetric and low noise chevron nozzle set are investigated in the context of shielding. The unshielded chevron nozzle set shows 1 to 2 dB of source noise reduction (relative to the unshielded axisymmetric nozzle set) with some penalties at higher frequencies. Shielding of the axisymmetric nozzles shows up to 6.5 dB of reduction at high frequency. The combination of shielding and low noise chevrons shows benefits beyond the expected additive benefits of the two, up to 10 dB, due to the effective migration of the jet source peak noise location upstream for increased shielding effectiveness. Jet noise source maps from phased array results processed with the Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS) algorithm reinforce these observations.

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“…Another factor requiring consideration is the relatively lower frequency ranges of interrogation and lower sound pressure levels associated with full-scale UAV and small propellers as compared to the scaled JES articles most recently tested in the LSAWT. 4,5 Therefore, the axial location of the collector was varied to reduce the potential levels of recirculation and ascertain its effect on the facility noise levels. An experimental windscreen was also utilized on one of the linear array microphones near the collector face (θ o = 137.5 • ) to qualitatively determine how much of the empty facility noise is microphone self-noise due to flow recirculation.…”

Section: Facility Noise Levelsmentioning

confidence: 99%

Small Propeller and Rotor Testing Capabilities of the NASA Langley Low Speed Aeroacoustic Wind Tunnel

Zawodny

Haskin

2017

23rd AIAA/CEAS Aeroacoustics Conference

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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 freestream 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 configurations, 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.

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Acoustic Characterization of Compact Jet Engine Simulator Units

Cited by 4 publications

References 14 publications

Jet noise shielding provided by a hybrid wing body aircraft

Jet noise shielding provided by a hybrid wing body aircraft

Jet Noise Shielding Provided by a Hybrid Wing Body Aircraft

Small Propeller and Rotor Testing Capabilities of the NASA Langley Low Speed Aeroacoustic Wind Tunnel

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