SOUND-ABSORBING STRUCTURE FOR AIRCRAFT ENGINE Russian patent published in 2022 - IPC G10K11/172 

FIELD: physics.

SUBSTANCE: invention relates to sound-absorbing structures. Structure comprises a sound-absorbing filler with attached perforated path and extra-path shells, a cellular filler with an irregular structure, the cells of which are formed by non-parallel walls, wherein for all pairs of opposite non-parallel walls the condition 0°< α < 45° is satisfied where are the normals of the pair of opposite walls in the cell, α is angle between normal line and for cell condition 0.6 < S_cir/S_cell < 0.91 is satisfied, where S_cir is the area of the circle inscribed in the cell, mm², S*₄ is the cross-sectional area of the cell, mm², warp or weft fibres of the membrane cover are not oriented relative to the walls in the cells of the cellular filler of the irregular structure, the pattern of the cover corresponds to the shape of each cell of the cellular filler with regular and irregular structures, wherein said cover can be treated with water-repellent composition before cutting out patterns from web / roll of material, or after cutting out patterns, or after placing pattern in cell. Selection of optimum parameters of the SLC is carried out based on the modal composition of the sound source, the blowing resistance R of the cover material is in range of 30…370 rel (SGS), nonlinearity coefficient takes a value of up to 2.3, cell depth H is 10…75 mm, depth h of the membrane in cell is 5…70 mm, percentage of perforation of tract casing is 2…20 %.

EFFECT: increased efficiency of engine noise suppression, reduced weight.

4 cl, 8 dwg