Patent ID: 11927133
Assignee: SAFRAN AIRCRAFT ENGINES
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  B  G  D | IPC B  D  F  G

Claim 12:
13. An acoustic attenuation edge designed to be installed on an aircraft turbine engine wall, in contact with a fluid flow, the acoustic attenuation edge comprising:
a porous coating (39) having a mesh structure,
an acoustically absorbent material (41) covered with the porous coating and having a first volume (Vabs), and
at least one cavity (45) located between the acoustically absorbent material (41) and the porous coating (39),, wherein the mesh structure has wires (390) separating between them mesh openings (391) passing through said mesh structure,, wherein
each of the mesh openings (391) has an elementary surface area (So), some of the mesh openings (391) are large enough to include a circle 0.05 mm in diameter, and
said at least one cavity (45) has a second volume (Vcav), the second volume is higher than three percent of a sum of the first volume and the second volume (Vcav>3% (Vcav+Vabs)),
the mesh structure forms a porous membrane and the porous membrane having the mesh structure:
is curved to a rounded apex, in a direction (51) of curvature,
has said wires (390) oriented in different directions in order to display said mesh openings (391) between them, and
displays, if considered in a lay flat condition, between two of said wires crossways to said direction of curvature:
a dimension Lx which is as a function of an angle ∝ formed between a tangent to the porous membrane, for a given section, and
an axis (55) passing through said rounded apex and through a median to the acoustically absorbent material (41) and Lx<0.1 mm/sin(∝).