Non-contacting seals for geared gas turbine engine bearing compartments

Patent metadata

Field	Value
Publication number	US-10352195-B2
Application number	US-201715402316-A
Country	US
Kind code	B2
Filing date	Jan 10, 2017
Priority date	Mar 7, 2013
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

A gas turbine engine includes a fan, a compressor section, a combustor, and a turbine section. The engine also includes a rotating element and at least one bearing compartment including a bearing for supporting the rotating element, a seal for resisting leakage of lubricant outwardly of the bearing compartment and for allowing pressurized air to flow from a chamber adjacent the seal into the bearing compartment. A method and section for a gas turbine engine are also disclosed.

First claim

The invention claimed is:

1. A gas turbine engine comprising:
a fan section, a bypass passage, a compressor section, and a turbine section arranged along an engine longitudinal axis;
a rotating element and at least one bearing compartment including a bearing for supporting said rotating element;
wherein said at least one bearing compartment has a first seal and a second seal each associated with a corresponding one of two opposed axial ends, on either axial side of said bearing relative to said engine longitudinal axis, at least one of said first seal and said second seal being a non-contacting seal having a seal face facing a rotating face of said rotating element; and
wherein a bypass ratio is defined as the volume of air passing into said bypass passage compared to the volume of air passing into said compressor section, wherein said bypass ratio is greater than 10 at a cruise condition.

2. The gas turbine engine as set forth in claim 1 , wherein said non-contacting seal is arranged to resist leakage of lubricant outwardly of said at least one bearing compartment and to allow pressurized air to flow from a chamber adjacent said non-contacting seal into said at least one bearing compartment, and a grooved area is formed in one of said faces, with said grooved area having a plurality of circumferentially spaced grooves for generating hydrodynamic lift-off forces and allowing leakage of pressurized air across said faces and into said at least one bearing compartment to resist leakage of lubricant from said at least one bearing compartment.

3. The gas turbine engine as set forth in claim 2 , wherein said non-contacting seal being formed with a plurality of passages configured to allow tapping of additional pressurized air to be delivered to the faces at a location in the proximity of the grooved area for generating hydrostatic lift-off forces.

4. The gas turbine engine as set forth in claim 3 , wherein said grooved area is spaced radially from said plurality of passages at said seal face.

5. The gas turbine engine as set forth in claim 4 , wherein each of said plurality of passages is positioned radially outward of said grooved area.

6. The gas turbine engine as set forth in claim 5 , wherein said rotating element is a shaft rotating with a rotor having an axial face facing said seal face.

7. The gas turbine engine as set forth in claim 6 , wherein said grooved area is formed in said rotor.

8. The gas turbine engine as set forth in claim 1 , wherein said turbine section includes a fan drive turbine configured to drive said fan section through a gear arrangement, said rotating element being driven by the fan drive turbine.

9. The gas turbine engine as set forth in claim 8 , wherein each of said first seal and said second seal is a non-contacting seal.

10. The gas turbine engine as set forth in claim 8 , wherein said rotating element is a shaft rotating with a rotor having a circumferential face facing said seal face.

11. The gas turbine engine as set forth in claim 10 , wherein said seal face faces radially inwardly.

12. The gas turbine engine as set forth in claim 11 , wherein a grooved area is formed in one of said faces, with said grooved area having a plurality of circumferentially spaced grooves for generating hydrodynamic lift-off forces and allowing leakage of pressurized air across said faces and into the at least one bearing compartment to resist leakage of lubricant from the at least one bearing compartment.

13. The gas turbine engine as set forth in claim 11 , wherein said non-contacting seal is a controlled gap carbon seal having a full hoop seal and a metal band shrunk fit onto the non-contacting seal, and positioned in a seal carrier.

14. The gas turbine engine as set forth in claim 8 , wherein said fan drive turbine is configured to drive said gear arrangement, said fan drive turbine defining a turbine pressure ratio greater than 5:1, measured prior to an inlet of said fan drive turbine as related to a pressure at an outlet of said fan drive turbine prior to an exhaust nozzle.

15. The gas turbine engine as set forth in claim 14 , wherein said at least one bearing compartment being associated with said gear arrangement.

16. The gas turbine engine as set forth in claim 1 , wherein said fan section comprises at least one fan blade, with a low fan pressure ratio of less than 1.45, the low fan pressure ratio measured across the at least one fan blade alone.

17. The gas turbine engine as set forth in claim 16 , wherein said rotating element is configured to rotate at a velocity greater than or equal to about 450 feet per second, and said gear arrangement defines a gear reduction ratio of greater than 2.3:1.

18. A method of operating a gas turbine engine, the method comprising the steps of:
arranging a bearing within a bearing compartment to support a rotating element, said rotating element defining a rotating face, said bearing compartment having a first seal and a second seal each associated with a corresponding one of two opposed axial ends, on either axial side of said bearing;
rotating said rotating face relative to at least one of said first seal and said second seal;
sealing said bearing compartment with said first seal and said second seal, at least one of said first seal and said second seal being a non-contacting seal configured to resist leakage of lubricant outwardly of said bearing compartment and to allow air to flow from a chamber adjacent said seal and into said bearing compartment, said non-contacting seal defining a seal face facing said rotating face; and
communicating air from a fan to a bypass passage and to compressor section, wherein a bypass ratio is defined as the volume of air passing into said bypass passage compared to the volume of air passing into said compressor section, said bypass ratio greater than 10 at a cruise condition.

19. The method as set forth in claim 18 , wherein said rotating element is a shaft rotatable with a rotor having an axial face facing said seal face.

20. The method as set forth in claim 18 , wherein said step of rotating comprises rotating said rotating element at a velocity greater than or equal to 450 feet per second, and said fan comprises at least one fan blade, with a low fan pressure ratio of less than 1.45, the low fan pressure ratio measured across the at least one fan blade alone.

Assignees

• United Technologies Corp

Inventors

• Ullah M Rifat
• Peters Robert E

Classifications

• F01D25/168

  for axial load mainly · CPC title

• F16C32/0633

  the liquid being retained in a gap · CPC title

• F01D11/02

  by non-contact sealings, e.g. of labyrinth type (for sealing space between rotor blade tips and stator F01D11/08) · CPC title

• F16J15/342

  with means for feeding fluid directly to the face · CPC title

• F01D25/186 Primary

  for sliding contact bearing · CPC title