Piston ring assembly for a turbine engine

Patent metadata

Field	Value
Publication number	US-11898494-B2
Application number	US-202117502502-A
Country	US
Kind code	B2
Filing date	Oct 15, 2021
Priority date	Sep 2, 2015
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

A gas turbine engine is provided having a combustion section with a liner extending between a forward end and an aft end. A structural member is positioned in or around at least a portion of the combustion section. Additionally, a piston ring holder is provided attached to the structural member at a first end and positioned proximate to the aft end of the liner at a second end. The piston ring holder is a bimetallic member including a first portion formed of a first material and a second portion formed of a second material. A coefficient of thermal expansion of the first material is different than a coefficient of thermal expansion of the second material.

First claim

What is claimed is:

1. A gas turbine engine defining an axial direction, the gas turbine engine comprising:
a combustion section including a liner extending between a forward end and an aft end generally along the axial direction, the liner at least partially defining a combustion chamber;
a structural member positioned in or around at least a portion of the combustion section;
a piston ring configured to extend around the aft end of the liner; and
a piston ring holder including a first end and a second end, the piston ring holder attached to the structural member at the first end and positioned proximate to the piston ring at the second end, the piston ring holder further including:
a first portion comprised of a first metal material having a first coefficient of thermal expansion, αH1, and
a second portion comprised of a second metal material having a second coefficient of thermal expansion, αH2, the first coefficient of thermal expansion, αH1, being different than the second coefficient of thermal expansion, αH2,

wherein the piston ring holder has a unitary non-separable configuration between the first portion and the second portion, and
wherein the piston ring holder is free of ceramic materials.

2. The gas turbine engine of claim 1 , wherein the first coefficient of thermal expansion, αH1, is greater than the second coefficient of thermal expansion, αH2.

3. The gas turbine engine of claim 1 , wherein the first coefficient of thermal expansion, αH1, is at least about ten percent greater than the second coefficient of thermal expansion, αH2, in a temperature range of 1000 degrees Fahrenheit and 1600 degrees Fahrenheit.

4. The gas turbine engine of claim 1 , wherein the piston ring holder further includes a slot at the second end, and wherein the piston ring is positioned in the slot of the piston ring holder and is configured to contact the aft end of the liner.

5. The gas turbine engine of claim 4 , wherein the piston ring is a bimetallic piston ring comprised of a first material having a first coefficient of thermal expansion, αPR1, and a second material having a second coefficient of thermal expansion, αPR2, the first coefficient of thermal expansion, αPR1, being different than the second coefficient of thermal expansion, αPR2.

6. The gas turbine engine of claim 5 , wherein the piston ring is an outer piston ring, wherein the second material of the piston ring is positioned closer to the liner of the combustion section than the first material of the piston ring, and wherein the second coefficient of thermal expansion, αPR2, of the second material of the piston ring is at least about ten percent less than the first coefficient of thermal expansion, αPR1, of the first material of the piston ring.

7. The gas turbine engine of claim 4 , wherein the piston ring defines a contact surface that contacts the aft end of the liner, and wherein the piston ring further defines a chamfer at an aft end of the contact surface.

8. The gas turbine engine of claim 4 , further comprising a spring element positioned in the slot of the piston ring holder configured to press the piston ring towards the aft end of the liner.

9. The gas turbine engine of claim 8 , wherein the spring element includes one or more cockle springs.

10. The gas turbine engine of claim 1 , wherein the piston ring holder includes a flange positioned at the first end attached to the structural member, a slot positioned at the second end, and an arm extending from the flange to the slot, wherein the first portion of the piston ring holder includes the flange and at least a part of the arm, and wherein the second portion of the piston ring holder includes the slot and at least a portion of the arm.

11. The gas turbine engine of claim 1 , wherein the structural member is one of a combustor casing or an inner annular support member.

12. A piston ring assembly for a gas turbine engine including a structural member positioned in or around at least a portion of a combustion section, the combustion section having a liner extending between a forward end and an aft end, the piston ring assembly comprising:
a piston ring configured to extend around the aft end of the liner; and
a piston ring holder including a first end attached to the structural member and a second end positioned proximate the piston ring at the second end, the piston ring holder further including
a first portion comprised of a first metal material having a first coefficient of thermal expansion, αH1, and
a second portion comprised of a second metal material having a second coefficient of thermal expansion, αH2, the first coefficient of thermal expansion, αH1, being different than the second coefficient of thermal expansion,

wherein the piston ring holder has a unitary non-separable configuration between the first portion and the second portion and
wherein the piston ring holder is free of ceramic materials.

13. The piston ring assembly of claim 12 , wherein the piston ring is a bimetallic piston ring comprised of a first material having a first coefficient of thermal expansion, αPR1, and a second material having a second coefficient of thermal expansion, αPR2, the first coefficient of thermal expansion, αPR1, being different than the second coefficient of thermal expansion, αPR2.

14. The piston ring assembly of claim 13 , wherein the second material of the piston ring is configured to be positioned closer to the liner of the combustion section than the first material of the piston ring, and wherein the first coefficient of thermal expansion, αPR1, of the first material of the piston ring is higher than the second coefficient of thermal expansion, αPR2, of the second material of the piston ring.

15. The piston ring assembly of claim 12 , wherein the piston ring holder further includes an arm extending from the first end to the second end, wherein the first portion of the piston ring holder comprises at least a portion of the arm.

16. The piston ring assembly of claim 15 , wherein at least about sixty percent of the arm comprises the first metal material and comprises part of the first portion.

17. The piston ring assembly of claim 12 , wherein the piston ring is an outer piston ring.

18. The piston ring assembly of claim 12 , wherein the first portion comprises at least one bend.

19. The piston ring assembly of claim 18 , wherein the at least one bend comprises at least one U-shaped bend.

Assignees

• Gen Electric

Inventors

• Bloom Nicholas John
• Stieg Michael Alan
• Towle Brian Christopher

Classifications

• F02C7/20 Primary

  Mounting or supporting of plant; Accommodating heat expansion or creep · CPC title

• F02C7/28

  Arrangement of seals · CPC title

• F23R3/007 Primary

  constructed mainly of ceramic components · CPC title

• F23R3/50

  Combustion chambers comprising an annular flame tube within an annular casing (toroidal combustion chambers F23R3/52) · CPC title

• F23R3/60 Primary

  Support structures; Attaching or mounting means · CPC title