Attenuation of FJ44 Turbofan Engine Noise with a Foam-Metal Liner Installed Over-the-Rotor

Sutliff, Daniel L.; Elliott, David; Jones, Michael G.; Hartley, Thomas

doi:10.2514/6.2009-3141

Cited by 30 publications

(25 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The third, conducted with a stainless steel OTR metal foam liner in a Williams International FJ44-3A engine (20-inch-diameter fan used for business jets), demonstrated significant broadband noise reduction at up to transonic fan tip speeds, with corresponding flow speeds through the inlet up to just less than Mach 0.6. 10,11 These results clearly demonstrate that OTR metal foam liners offer significant noise reduction potential, but further investigation is needed to optimize their implementation.…”

Section: Introductionmentioning

confidence: 82%

See 1 more Smart Citation

Assessment of Soft Vane and Metal Foam Engine Noise Reduction Concepts

Jones

Parrott

Sutliff

et al. 2009

15th AIAA/CEAS Aeroacoustics Conference (30th AIAA Aeroacoustics Conference)

Self Cite

View full text Add to dashboard Cite

Two innovative fan-noise reduction concepts developed by NASA are presented -soft vanes and over-the-rotor metal foam liners. Design methodologies are described for each concept. Soft vanes are outlet guide vanes with internal, resonant chambers that communicate with the exterior aeroacoustic environment via a porous surface. They provide acoustic absorption via viscous losses generated by interaction of unsteady flows with the internal solid structure. Over-the-rotor metal foam liners installed at or near the fan rotor axial plane provide rotor noise absorption. Both concepts also provide pressure-release surfaces that potentially inhibit noise generation. Several configurations for both concepts are evaluated with a normal incidence tube, and the results are used to guide designs for implementation in two NASA fan rigs. For soft vanes, approximately 1 to 2 dB of broadband inlet and aft-radiated fan noise reduction is achieved. For over-the-rotor metal foam liners, up to 3 dB of fan noise reduction is measured in the low-speed fan rig, but minimal reduction is measured in the high-speed fan rig. These metal foam liner results are compared with a static engine test, in which inlet sound power level reductions up to 5 dB were measured. Brief plans for further development are also provided.

show abstract

Section: Introductionmentioning

confidence: 82%

“…Multiple FeCrAlY samples were tested with the NIT and the Two-Thickness Method (Eqs. [10][11][12][13][14] As mentioned earlier, the frequency range of interest for noise reduction with the HSFR was approximately 1600 to 5300 Hz. Clearly, the results in Fig.…”

Section: Foam Evaluationmentioning

confidence: 99%

Assessment of Soft Vane and Metal Foam Engine Noise Reduction Concepts

Jones

Parrott

Sutliff

et al. 2009

15th AIAA/CEAS Aeroacoustics Conference (30th AIAA Aeroacoustics Conference)

Self Cite

View full text Add to dashboard Cite

show abstract

“…This technology extends the liner over the rotation plane of the fan as shown in Figure 4. [26] It is a general rule of thumb for acoustic mitigation that the noise be suppressed at the source rather than downstream [22] which is exactly what this technology seeks to accomplish. By mitigating the near field noise, the far field noise is reduced dramatically.…”

Section: Over-the-rotor Metal Foam Linermentioning

confidence: 99%

Noise Assessment of NASA Environmentally Responsible Aviation (ERA) Technologies and Concepts

Jiménez

Pfaender

Havrilesko

et al. 2012

12th AIAA Aviation Technology, Integration, and Operations (ATIO) Conference and 14th AIAA/ISSMO Multidisciplinary Analysis And

View full text Add to dashboard Cite

We present a comprehensive assessment of NASA Environmentally Responsible Aviation Project technologies across aircraft component, single event, and multi-event levels. Modeling capabilities appropriate for each level of abstraction are introduced. We examine noise technologies in terms of component-level performance effects, modeling considerations, and aircraft-level impacts. Single event performance results include discussion of reference vehicle models and their accuracy, as well as modeled vehicle performance in the form of noise certification point measurements and single event contours. We then present an assessment of the technology portfolio in the context of a generic airport multi-event study where the noise performance of industry project aircraft expected to enter the market over the next decade is also approximated. Results discussed provide a comprehensive characterization of noise reductions achievable with technologies in question and provide further analytical support for their continued development.

show abstract

“…In addition to conventional fan liners, two advanced technologies are applied: soft vane stators 28 and over-the-rotor foam metal treatment. 29 Both of these technologies are applications of acoustic treatment in areas of the engine which currently do not have treatment: on the surface of the fan vanes and above the fan rotor tips. Soft vane stators have small Helmholtz resonator chambers inside the airfoils and are covered by a porous surface material over a portion of the chord near the leading edge.…”

Section: Methods Of Analysismentioning

confidence: 99%

An Analytical Assessment of NASA's N+1 Subsonic Fixed Wing Project Noise Goal

Berton

Envia

Burley

2009

15th AIAA/CEAS Aeroacoustics Conference (30th AIAA Aeroacoustics Conference)

View full text Add to dashboard Cite

The Subsonic Fixed Wing Project of NASA's Fundamental Aeronautics Program has adopted a noise reduction goal for new, subsonic, single-aisle, civil aircraft expected to replace current 737 and A320 airplanes. These so-called "N+1" aircraft -designated in NASA vernacular as such since they will follow the current, in-service, "N" airplanes -are hoped to achieve certification noise goal levels of 32 cumulative EPNdB under current Stage 4 noise regulations. A notional, N+1, single-aisle, twinjet transport with ultrahigh bypass ratio turbofan engines is analyzed in this study using NASA software and methods. Several advanced noise-reduction technologies are empirically applied to the propulsion system and airframe. Certification noise levels are predicted and compared with the NASA goal.

show abstract

Attenuation of FJ44 Turbofan Engine Noise with a Foam-Metal Liner Installed Over-the-Rotor

Cited by 30 publications

References 6 publications

Assessment of Soft Vane and Metal Foam Engine Noise Reduction Concepts

Assessment of Soft Vane and Metal Foam Engine Noise Reduction Concepts

Noise Assessment of NASA Environmentally Responsible Aviation (ERA) Technologies and Concepts

An Analytical Assessment of NASA's N+1 Subsonic Fixed Wing Project Noise Goal

Contact Info

Product

Resources

About