In-Duct and Farfield Experimental Measurements from the ANCF for the Purpose of Improved Broadband Liner Optimization

Sutliff, Daniel L.; Jones, Michael G.; Nark, Douglas M.

doi:10.2514/6.2014-3231

Cited by 14 publications

(10 citation statements)

References 8 publications

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“…20,21 The system provided a set of consistent modes to evaluate several axial spacings of the dual rakes which would not be feasible with a fan source. Parametric sets of insertion loss databases 22 were acquired for the purpose of validating a novel liner design and manufacturing methodology. 23 A constant impedance liner and variable impedance liner were evaluated using the CFANS system in the vertical build.…”

Section: Significant Resultsmentioning

confidence: 99%

Artificial noise systems for parametric studies of turbo-machinery aero-acoustics

Sutliff

Walker

2016

International Journal of Aeroacoustics

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The study of turbo-machinery aero-acoustics encompasses source generation, duct propagation, and radiation to the far field for the purposes of physical understanding, evaluation, and noise reduction. Further, the acoustics subset can be divided into overall, broadband, or tone emphasis. Ultimately, assessments on full-scale turbofans are required. However, for isolating specific effects, or for costs reasons, it is useful to test models. These models may be scaled versions of turbofan components depending on the physical process of interest. The advantage of using models is the lower cost allows for a wider range of conditions to be studied. Even so, the cost of manufacturing and testing scale model fans in mid-technology readiness level can be limiting. A potentially useful supplement to turbo-machinery aero-acoustics studies is the use of artificial sources to generate acoustic signatures. The advantage is that a wide range of signatures can be quickly and efficiently studied, particularly useful for noise reduction concepts, or validating prediction methodologies that are sensitive to variations in geometry or acoustic signature. A disadvantage is the lack of the ability to study source generation. This trade-off must be considered carefully when deciding on the usefulness of utilizing fan artificial noise sources for the study of turbo-machinery aero-acoustics. This paper presents two test articles that have contributed to turbo-machinery aero-acoustics studies. One is a 48 in. diameter duct (nominally full-scale) generating acoustic signatures in the audible range; the second is a 6 in. diameter duct (nominally scaled) generating acoustic signatures in the ultrasonic range.

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Section: Significant Resultsmentioning

confidence: 99%

Artificial noise systems for parametric studies of turbo-machinery aero-acoustics

Sutliff

Walker

2016

International Journal of Aeroacoustics

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“…Further discussion of the ANCF and full test program may be found in a companion paper. 3 However, this work focuses on the liner design and evaluation process for an additional configuration used for initial testing. In addition to the standard horizontal configuration, testing was conducted with the ANCF hardware in a vertical orientation to provide a clean, annular duct for experimentation.…”

Section: Test Configurationmentioning

confidence: 99%

“…The measured values are obtained from the aforementioned rotating rake data which, based on previous experience, are assumed to have a measurement error of + /−1 dB. 3 The predicted values are those presented in Section IV with error bars representing the 95% confidence intervals for the mean attenuation. The DDOF liner was tested only in the τ = 0.5 configuration, for which comparison of measured and predicted attenuations are presented in Figure 9a.…”

Section: Liner Performance Evaluationmentioning

confidence: 99%

Improved Broadband Liner Optimization Applied to the Advanced Noise Control Fan

Nark

Jones

Sutliff

et al. 2014

20th AIAA/CEAS Aeroacoustics Conference

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“…Initial liner designs targeting the NASA Langley Liner Technology Facility 8,9 (LTF) resulted in predicted optimum impedance spectra consistent with those obtained using higher-fidelity, more computationally intensive models 10 . Subsequent design and testing in the NASA Glenn Advanced Noise Control Fan (ANCF) Rig 3,4 and 9-ft x 15-ft Low Speed Wind Tunnel 5,6 provided further confidence in the design process. Based on these results, additional validation was pursued through the fabrication and testing of liner designs for the NASA Glenn DGEN Aero-propulsion Research Turbofan (DART) and is the focus of this work.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, improved broadband liner designs must account for these constraints and take advantage of novel liner configurations. With these observations in mind, the development and assessment of a broadband acoustic liner optimization process has been pursued through a series of recent design and experimental studies 1,2,3,4,5,6,7 .…”

Section: Introductionmentioning

confidence: 99%

Design and Acoustic Efficacy of a Broadband Liner for the Inlet of the DGEN Aero-propulsion Research Turbofan

Sutliff

Nark

Jones

et al. 2019

25th AIAA/CEAS Aeroacoustics Conference

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Advanced fan designs (including higher bypass ratios) and shorter engine nacelles have highlighted a need for increased fan noise reduction over a broader frequency range. With these observations in mind, an acoustic liner optimization process has been developed to achieve improved broadband liner designs. A series of advanced liner design studies at increasing technology readiness levels have been conducted as the overall optimization methodology has been enhanced. As part of the analysis, the overall design and evaluation capability was extended such that external observer locations may be included in the optimization process. This enhancement will provide a much wider design space in designing advanced broadband liners. In this work, further validation was pursued through the fabrication and testing of two liner designs for the NASA Glenn DGEN Aero-propulsion Research Turbofan (DART). The DART was used to document the efficacy of acoustic liners installed in the inlet of the DGEN380. An advanced Multi-Degree of Freedom Liner was designed, fabricated, and tested, along with a traditional Single-Degree-of-Freedom liner, and those results compared to a hardwall baseline inlet. Farfield acoustic data were acquired from an external array, evaluated and reported herein terms of overall, broadband, and tonal components of the insertion loss. The predicted attenuation results generally matched expected trends of the measured data for the conditions considered.

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In-Duct and Farfield Experimental Measurements from the ANCF for the Purpose of Improved Broadband Liner Optimization

Cited by 14 publications

References 8 publications

Artificial noise systems for parametric studies of turbo-machinery aero-acoustics

Artificial noise systems for parametric studies of turbo-machinery aero-acoustics

Improved Broadband Liner Optimization Applied to the Advanced Noise Control Fan

Design and Acoustic Efficacy of a Broadband Liner for the Inlet of the DGEN Aero-propulsion Research Turbofan

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