Multi-layer sound-absorbing structure of a double-flow turbojet engine Russian patent published in 2021 - IPC F02C7/24 

FIELD: aircraft construction.

SUBSTANCE: invention relates to multilayer sound-absorbing structures for use in aircraft construction, as well as in aircraft turbojet engine manufacturing. The multilayer sound-absorbing structure of a double-circuit turbojet engine contains a perforated track wall and a sound-proof wall connected at the contact sites by a composite adhesive material with a tubular and/or sine wave core placed between them, which consists of two or more layers. On the contact areas of the core, which are located at the junction with the perforated tract wall and form rows of parallel strips, rows of longitudinal through grooves are made, which are located symmetrically along the width of the contact areas, which is equal to 1.4-1.7 of the width of the through grooves, through grooves in adjacent rows of parallel stripes are arranged in a chessboard fashion. The length of the through groove is 10-12 of its width, and the distance between two adjacent through grooves of one row is equal to the width of the through openings in adjacent rows are arranged in a chessboard fashion. The diameter of the through openings of one row is equal to the distance between two adjacent rows of through openings and makes up 0.90-0.95 of the width of the through slot. The rows of longitudinal through grooves are parallel to the rows of through openings.

EFFECT: technical result consists in improved efficiency of sound absorption in a wide frequency range of a multilayer sound-absorbing structure, as well making the multilayer sound-absorbing structure manufacturing less labor-intensive.

4 cl, 3 dwg