Multi-layer acoustic treatment panel
View Patent ↗A multilayer acoustic treatment panel including a first cellular-structure core sandwiched between a perforated skin and an intermediate skin; and a second cellular-structure core sandwiched between the intermediate skin and a continuous skin. The perforated skin includes at least one pair of high-porosity zones presenting a perforation ratio greater than a perforation ratio of a remainder of the perforated skin and including an inlet zone and an outlet zone longitudinally spaced apart from each other, the high-porosity zones of a given pair communicating through the first cellular-structure core and the intermediate skin with the two ends of a soundwave flow channel arranged in the second cellular-structure core.
1. A multilayer acoustic treatment panel comprising:
a first cellular-structure core sandwiched between a perforated skin and an intermediate skin; and
a second cellular-structure core sandwiched between the intermediate skin and a continuous skin;
wherein the perforated skin includes at least one pair of high-porosity zones presenting a perforation ratio greater than a perforation ratio of a remainder of the perforated skin and including an inlet zone and an outlet zone that are longitudinally spaced apart from each other, the high-porosity zones of a given pair communicating through the first cellular-structure core and the intermediate skin with two ends of a soundwave flow channel arranged in the second cellular structure core;
wherein the intermediate skin is perforated except for zones overlying a portion of the first cellular-structure core bounded by the soundwave flow channel, the zones being continuous.
2. A panel according to claim 1 , wherein the high-porosity zones of a given pair communicate with the soundwave flow channel via wells passing both through the first cellular-structure core and the intermediate skin.
3. A panel according to claim 1 , wherein the high-porosity zones of a given pair communicate with the soundwave flow channel via wells passing through the first cellular-structure core and via a plurality of orifices formed through the intermediate skin.
4. A panel according to claim 1 , wherein the high-porosity zones of a given pair communicate with the soundwave flow channel through passages formed between cavities of the first cellular-structure core and a plurality of orifices formed through the intermediate skin.
5. A panel according to claim 1 , wherein the zones of the intermediate skin overlying the first cellular-structure core bounded by the soundwave flow channel.
6. A panel according to claim 1 , wherein the soundwave flow channel is formed by a corridor that is defined laterally by walls of the second cellular-structure core.
7. A panel according to claim 1 , wherein the soundwave flow channel is formed by an array of adjacent cavities of the second cellular-structure core that communicate with one another via porous walls.
8. A panel according to claim 1 , wherein the perforated skin includes a plurality of pairs of high-porosity zones that are transversely spaced from one another.
9. A panel according to claim 8 , wherein the inlet zones and the outlet zones are in alignment in directions that are substantially transverse relative to the panel.
10. A turbojet nacelle comprising at least one acoustic treatment panel according to claim 1 on an inside face thereof.
11. A nacelle according to claim 10 , wherein the perforated skin of the acoustic treatment panel is in contact with a cold stream flow passage defined on an outside by the inside face of the nacelle.
12. A turbojet including at least one acoustic treatment panel according to claim 1 on an outside face thereof.
13. A turbojet according to claim 12 , wherein the perforated skin of the acoustic treatment panel is in contact with a cold stream flow passage defined on an inside by the outside face of the turbojet.