Acoustic liner for gas turbine engine components

Patent metadata

Field	Value
Publication number	US-2017191414-A1
Application number	US-201514984767-A
Country	US
Kind code	A1
Filing date	Dec 30, 2015
Priority date	Dec 30, 2015
Publication date	Jul 6, 2017
Grant date	—

Abstract

A single degree of freedom (SDOF) acoustic liner includes a porous face sheet, a substantially imperforate back sheet generally parallel to and opposing said porous face sheet and defining a thickness therebetween, and an acoustic core layer of contiguous adjacent resonant cavities disposed between the porous face sheet and the imperforate back sheet. The acoustic core layer includes a first resonant cell having a first internal volume therein and a second resonant cell having a second internal volume therein different than the first internal volume. A cell partition wall extends between the porous face sheet and the imperforate back sheet, and separates and seals the first resonant cell from the second resonant cell. In a thickness direction, and perpendicular to a plane generally parallel with the porous face sheet and the substantially imperforate back sheet, the first internal volume overlaps the second internal volume over the cell partition wall.

First claim

What is claimed is:

1 . A single degree of freedom (SDOF) acoustic liner comprising:
a porous face sheet; a substantially imperforate back sheet generally parallel to and opposing said porous face sheet; and an acoustic core layer of contiguous adjacent resonant cavities disposed between said porous face sheet and said imperforate back sheet, a thickness of said acoustic core layer being defined as a distance between said porous face sheet and said substantially imperforate back sheet, said acoustic core layer comprising:
a first resonant cell having a first internal volume therein, and a second resonant cell having a second internal volume therein, said first internal volume being different than said second internal volume; and
a cell partition wall extending between said porous face sheet and said imperforate back sheet, said cell partition wall separating and sealing said first resonant cell from said second resonant cell,
wherein, in the thickness direction, and perpendicular to a plane generally parallel with said porous face sheet and said substantially imperforate back sheet, said first internal volume overlaps said second internal volume over said cell partition wall.

2 . The acoustic liner as claimed in claim 1 , wherein said cell partition wall comprises a bent portion along the generally parallel plane.

3 . The acoustic liner as claimed in claim 2 , wherein said first resonant cell comprises a first cell depth and a second cell depth, said first cell depth substantially equal to said acoustic core layer thickness and said second cell depth equal to a distance between said partition wall bent portion and said substantially imperforate back sheet.

4 . The acoustic liner as claimed in claim 3 , wherein said first internal volume is greater than said second internal volume.

5 . An acoustic honeycomb structure, comprising at least one heptad of contiguous adjacent resonant cavities arranged substantially parallel to one another in a hexagonal grid formation, wherein said at least one heptad comprises:
a central hexagonal tube comprising six lateral walls arranged evenly about a central tube axis, said six lateral walls each extending along said central tube axis from a first opposing tube end to a second opposing tube end, said six lateral walls defining a first central hexagonal base opening disposed at said first opposing tube end and a second central hexagonal base opening disposed at said second opposing tube end; and six adjacent hexagonal tubes radially surrounding said central hexagonal tube about said central tube axis, each of said six adjacent hexagonal tubes extending from said first opposing tube end to said second opposing tube end and including a first adjacent hexagonal base opening disposed at said first opposing tube end and a second adjacent hexagonal base opening disposed at said second opposing tube end, wherein said first central hexagonal base opening is generally parallel to said second central hexagonal base opening, wherein said first adjacent hexagonal base opening is generally parallel to said second adjacent hexagonal base opening, and wherein said second central hexagonal base opening is larger than said first central hexagonal base opening.

6 . The acoustic honeycomb structure as claimed in claim 5 , wherein each of said six lateral walls is commonly shared with a respective one of said six adjacent hexagonal tubes.

7 . The acoustic honeycomb structure as claimed in claim 6 , wherein said six lateral walls each comprise a first rectangular wall portion and a second rectangular wall portion, and wherein said second rectangular wall portion is disposed at a greater radial distance from said central tube axis than said first rectangular wall portion.

8 . The acoustic honeycomb structure as claimed in claim 7 , wherein each of said six lateral walls further comprises a radial shelf connecting said first rectangular wall portion with said second rectangular wall portion.

9 . The acoustic honeycomb structure as claimed in claim 8 , wherein said at least one heptad comprises a first heptad and a second heptad disposed adjacent said first heptad in said hexagonal grid formation.

10 . The acoustic honeycomb structure as claimed in claim 9 , wherein said first heptad shares one of said six adjacent hexagonal tubes in common with second heptad.

11 . The acoustic honeycomb structure as claimed in claim 10 , wherein said in common one of said six adjacent hexagonal tubes comprises at least two separate radial shelves of two separate central hexagonal tubes, respectively.

12 . The acoustic honeycomb structure as claimed in claim 8 , wherein said central hexagonal tube comprises a central interior volume, said each adjacent hexagonal tube comprises an adjacent interior volume, and said central interior volume is greater than said adjacent interior volume.

13 . The acoustic honeycomb structure as claimed in claim 12 , wherein said central interior volume corresponds to a first suppression frequency.

14 . The acoustic honeycomb structure as claimed in claim 13 , wherein said adjacent interior volume corresponds to a second suppression frequency different from said first suppression frequency.

15 . The acoustic honeycomb structure as claimed in claim 12 , wherein said central interior volume and said adjacent interior volume overlap over said radial shelf in the direction of said central tube axis.

16 . The acoustic honeycomb structure as claimed in claim 5 , wherein said first central hexagonal base opening and said first adjacent hexagonal base opening comprise regular hexagonal shapes.

17 . The acoustic honeycomb structure as claimed in claim 13 , wherein said first central hexagonal base opening has substantially the same dimensions as said first adjacent hexagonal base opening.

18 . The acoustic honeycomb structure as claimed in claim 5 , wherein said first adjacent hexagonal base opening is larger than said second adjacent hexagonal base opening.

19 . The acoustic honeycomb structure as claimed in claim 5 , wherein said second adjacent hexagonal base opening comprises an irregular convex hexagonal shape.

20 . A gas turbine engine comprising:
a fan assembly including a plurality of circumferentially spaced fan blades powered by a power turbine; a fan casing surrounding said fan assembly; and an acoustic liner disposed between said fan assembly and said fan casing, said acoustic liner comprising a porous face sheet facing said fan assembly, a substantially imperforate back sheet generally parallel to and opposing said porous face sheet, and an acoustic core layer of contiguous adjacent resonant cavities disposed between said porous face sheet and said imperforate back sheet, a thickness of said acoustic core layer being defined as a distance between said porous face sheet and said substantially imperforate back sheet, said acoustic core layer comprising:
a first resonant cell having a first internal volume therein, and a second resonant cell having a second volume therein, said first internal volume being different than said second internal volume; and
a cell partition wall extending between said porous face sheet and said imperforate back sheet, said cell partition wall separating and sealing said first resonant cell from said second resonant cell,
wherein, in a direction perpendicular to a plane generally parallel with said porous face sheet and said substantially imperforate back sheet, said first internal volume overlaps said second internal volu

Assignees

• Gen Electric
• Mra Systems Inc

Inventors

• Martinez Michael Moses
• Majjigi Rudramuni Kariveerappa
• Davies Steven Thomas
• Geertsema Egbert

Classifications

• G10K11/172

  using resonance effects · CPC title

• G10K11/168

  Plural layers of different materials, e.g. sandwiches · CPC title

• F05D2260/963

  by Helmholtz resonators · CPC title

• F05D2250/312

  the axes being parallel to each other · CPC title

• F05D2250/283

  honeycomb · CPC title