The Boeing Company

John Anthony Diamond

Thomas A Campbell

William Albert Voll

Integrated axially varying engine mufflers, and associated methods and systems. An arrangement in accordance with one embodiment of the invention includes a tailcone having a tapering external surface, a cavity disposed within the surface, and an engine muffler disposed within the cavity. The engine muffler can have a tapering outer surface, a porous inner surface disposed inwardly from the outer surface, and a plurality of cells disposed between the outer surface and the inner surface in fluid communication with the perforations of the inner surface. The inner surface can be positioned adjacent to an exhaust gas flow path having an entrance aperture and an exit aperture. Cells positioned toward the entrance aperture can have a first dimension extending away from the gas path, and cells positioned toward the exit aperture can have a second, different, dimension extending away from the exhaust gas path. Accordingly, the tapered muffler can be integrated with the tapered tailcone, and can provide sounds attenuation over a range of frequencies.

Integrated axially varying engine muffler, and associated methods and systems

An acoustic panel comprises a core layer of honeycomb whose opposite sides are covered by face sheets each comprising a perforated metal plate and a sheet of metal cloth such as woven wire or metal felt. The perforated metal plates are bonded to the core and the metal cloth sheets form the outer surfaces of the panel. Each metal cloth sheet has an acoustic resistance of 5 to 300 Rayls. The perforated metal plates have an open area of about 20 to 40 percent in preferred embodiments. Noise in a nozzle is suppressed by disposing a plurality of the acoustic panels in the nozzle duct with the panels oriented radially and spaced apart about a circumference of the duct.

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Kenmore, WA, United States of America

John Anthony Diamond