SOUND-ABSORBING PANEL FOR TURBOFAN PASSAGE Russian patent published in 2006 - IPC F02C7/24 

FIELD: aircraft engines.

SUBSTANCE: invention relates to devices for suppressing noise in turbofan aircraft engines. Proposed sound-absorbing panel has load-bearing housing wall, perforated passage, wall perforated wall in space out of passage, front layer of cellular filler, and rear layer of cellular filler. Front layer of cellular filler is located between perforated passage wall and wall in space out of passage. Rear layer of cellular filler is arranged between perforated wall in space out of passage and wall of load-bearing housing. Passage wall and front layer of cellular filler are made, each, of layers of fabric or band-based polymeric composite materials. Area of perforations of passage wall is 8.5-11.5% of wall area. Wall of load-bearing housing, perforated wall in space out of passage and rear layer of cellular filler are made of metal. Area of perforations of wall in space out of passage is 1.5-2.5% of wall area. Perimeters of cells of front and rear layers of cellular filler and thickness of passage wall are related so that perimeter of cells of front layer is equal to product of multiplication of acoustic parameters of channel of engine outer loop outer loop by perimeter of cells of rear layer of cellular filler by thickness of passage wall. Acoustic parameter of outer loop of engine is 0.707-3.16.

EFFECT: increased efficiency of sound absorption of turbofan engine passage without material losses in thrust.

5 cl, 4 dwg