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A gas turbine engine rotor containment structure comprises an inner structurally supporting case having an inner surface positioned adjacent to a gas turbine engine rotor component to be contained. A layer of acoustic material is wrapped around and bounded to a radially outer surface of the inner ca

A gas turbine engine rotor containment structure comprises an inner structurally supporting case having an inner surface positioned adjacent to a gas turbine engine rotor component to be contained. A layer of acoustic material is wrapped around and bounded to a radially outer surface of the inner case. A thin walled outer ring is bounded to a radially outer surface the layer of acoustic material. A layer of fibrous containment material surrounds a radially outer surface of the outer ring.

대표청구항 ▼

1. A turbofan engine comprising: a fan case surrounding a set of fan blades mounted for rotation about a central axis of the engine, the fan case having:a structurally supporting metal or composite inner shell having an axially extending wall with a radially inner side closely surrounding tips of th

1. A turbofan engine comprising: a fan case surrounding a set of fan blades mounted for rotation about a central axis of the engine, the fan case having:a structurally supporting metal or composite inner shell having an axially extending wall with a radially inner side closely surrounding tips of the fan blades and defining a continuous flow boundary surface from a first location fore of the fan blades to a second location aft of the fan blades, an axially extending nesting chamber defined on a radially outer side of the axially extending wall of the structurally supporting metal or composite inner shell, said nesting chamber extending from a third location fore of the fan blades to a fourth location aft of the fan blades, wherein the axially extending wall of the structurally supporting metal or composite inner shell has axially spaced-apart regions of different wall thicknesses along a length thereof, the thickness of the axially extending wall being greater at a leading edge of the fan blades than at a trailing edge thereof;an acoustic liner filling said nesting chamber, the acoustic liner axially spanning the fan blades;a stiffening ring secured to a radially outer surface of the acoustic liner and the structurally supporting metal or composite inner shell, the stiffening ring sealing the acoustic liner in the nesting chamber; andan outer blade containment fabric layer wrapped around the stiffening ring. 2. The turbofan engine defined in claim 1, wherein a front and a rear circumferential flange extend radially outwardly from the radially outer side of the axially extending wall of the structurally supporting metal or composite inner shell, the nesting chamber being defined between said front and rear flanges, and wherein the stiffening ring extends over said front and rear flanges and is bonded thereto to seal the acoustic liner in the nesting chamber. 3. The turbofan engine defined in claim 1, wherein the acoustic liner comprises a honeycomb structure defining a structural load path between the structurally supporting metal or composite inner shell and the stiffening ring, the acoustic liner being attached to both the structurally supporting metal or composite inner shell and the stiffening ring. 4. The turbofan engine defined in claim 1, wherein said structurally supporting metal or composite inner shell is a one-piece continuous metallic shell, and wherein said axially extending wall has a thickness which is greater in the vicinity of a leading edge of the fan blades than in the vicinity of a trailing edge of the fan blades. 5. The turbofan engine defined in claim 1, wherein said structurally supporting metal or composite inner shell, said stiffening ring and said acoustic liner have respective thicknesses T1, T2 and T3, and wherein T3 is greater than T1 and T2. 6. The turbofan engine defined in claim 1, wherein the outer blade containment fabric layer is made of a high-strength woven fibrous material containing fibres selected from a group consisting of: glass fibres, graphite fibres, carbon fibres, ceramic fibres, aromatic polyamide or aramide fibres and mixtures thereof. 7. The turbofan engine defined in claim 1, wherein the stiffening ring is made from metal sheet or from a composite sheeting material. 8. A turbofan engine comprising a fan case surrounding a circumferential array of fan blades mounted for rotation about an axis of the turbofan engine, the fan case having a structurally supporting inner shell having an axially extending annular wall with a radially inner side defining a flow boundary surface adjacent to tips of the fan blades for guiding an incoming flow of air, a thin walled stiffening ring surrounding the structurally supporting inner shell, a layer of honeycomb material sandwiched between the structurally supporting inner shell and the thin walled stiffening ring, the structurally supporting inner shell being made of a stronger material than the layer of honeycomb material, the layer of honeycomb material extending axially continuously from a location fore of the fan blades to a location aft of the fan blades, wherein the structurally supporting inner shell, the layer of honeycomb material and the thin walled stiffening ring are all connected together so as to form a structurally integrated assembly in which the honeycomb material contributes to increase a stiffness of the assembly as well as performing a structural load bearing function; and a layer of blade containment material wrapped around the stiffening ring to retain blades or blade fragments in the event of blade off event, wherein the structurally supporting inner shell has a wall thickness which is greater at the leading edge of the fan blades than at the trailing edge thereof. 9. The fan case defined in claim 8, wherein the layer of honeycomb material is bonded to a radially outer side of the axially extending annular wall of the structurally supporting inner shell and to a radially inner side of the thin walled stiffening ring. 10. The fan case defined in claim 8, wherein the layer of blade containment material comprises a high-strength fibrous fabric, and wherein the structurally supporting inner shell, the layer of honeycomb material and the stiffening ring being all three interposed between the fan blades and the high-strength fibrous fabric to protect the high strength fibrous fabric against blade rubbing. 11. The fan case defined in claim 10, wherein the high-strength fibrous fabric includes Kevlar®. 12. The fan case defined in claim 10, wherein the thickness of the axially extending wall of the structurally supporting inner shell and of the thin walled stiffening ring is less than the thickness of the layer of honeycomb material, the structurally supporting inner shell and the thin walled stiffening ring being made of metal or a composite material. 13. The fan case defined in claim 10, wherein an annular nesting chamber is defined between the structurally supporting inner shell and the thin walled-stiffening ring, the nesting chamber is closed at opposed axial ends thereof, said axial ends being respectively located fore and aft of the fan blades, and wherein the layer of honeycomb material extends axially continuously from one of the axial ends of the nesting chamber to the other one thereof. 14. A gas turbine engine containment structure comprising an inner structural case, the structural case having a radially inner cylindrical surface positioned around and adjacent to a gas turbine engine rotor component to be contained, a layer of acoustic material wrapped around and bounded to a radially outer cylindrical surface of the structural inner case, a thin walled stiffener ring bounded to a radially outer surface the layer of acoustic material, and a layer of high-strength fibrous containment material surrounding a radially outer surface of the thin walled stiffener ring, the inner structural case having a wall thickness which is greater at the leading edge of the rotor component than at the trailing edge thereof. 15. The gas turbine engine containment structure defined in claim 14, wherein inner structural case and the thin walled stiffener ring are made from a composite material or metal. 16. The gas turbine engine containment structure defined in claim 14, wherein the layer of high-strength fibrous containment material contains fibres selected from a group consisting of: glass fibres, graphite fibres, carbon fibres, ceramic fibres, aromatic polyamide or aramide fibres and mixtures thereof. 17. The gas turbine engine containment structure defined in claim 14, wherein the structural inner case has a radially outer cylindrical surface, the radially inner and radially outer cylindrical surfaces defining the wall thickness, and wherein said wall thickness varies to reach a maximum value in a region close to the gas turbine engine rotor component to be contained. 18. The gas turbine engine containment structure defined in claim 14, wherein the layer of acoustic material comprises a honeycomb foam composite material.