Turbine exhaust crack mitigation using partial collars

Patent metadata

Field	Value
Publication number	US-11248478-B2
Application number	US-201915734947-A
Country	US
Kind code	B2
Filing date	Jun 7, 2019
Priority date	Jun 7, 2018
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

An exhaust apparatus for a gas turbine includes an annular duct with struts extending from an outer duct-wall to an inner duct-wall of the annular duct. Each strut is encapsulated in a respective strut shield. An interface of the strut shield with a respective duct-wall includes a collar extending along a partial length of the perimeter of the strut shield at the respective interface. The collar includes a first section extending radially and aligned with the strut shield, and a second section oriented at an angle to the first section and aligned with the respective duct-wall. The first section is attached to the strut shield along a first joint and the second section is attached to the respective duct-wall along a second joint. An intersection of the first and second sections is formed by a smooth curve defined by a radius configured to distribute stresses at the respective interface.

First claim

The invention claimed is:

1. An exhaust apparatus for a gas turbine, comprising:
an annular duct extending axially along a machine axis of the gas turbine, the annular duct being radially delimited by an outer duct-wall and an inner duct-wall,
a plurality of struts, which are circumferentially distributed within the annular duct, wherein each strut extends at least from the outer duct-wall to the inner duct-wall and is encapsulated in a respective strut shield,
wherein each strut shield engages with the outer duct-wall along a first interface and engages with the inner duct-wall along a second interface,
wherein at least one of the first and second interfaces comprises:
at least one collar extending along a partial length of the perimeter of the strut shield at the respective interface, the collar comprising a first section extending radially and being aligned with the strut shield, and a second section oriented at an angle to the first section and being aligned with the respective duct-wall, the first section being attached to the strut shield along a first joint and the second section being attached to the respective duct-wall along a second joint, and
wherein an intersection of the first and second sections is formed by a smooth curve defined by a radius configured to distribute stresses at the respective interface.

2. The exhaust apparatus according to claim 1 , wherein the first joint is spaced from the intersection along a first direction and the second joint is spaced from the intersection along a second direction which is non-parallel to the first direction.

3. The exhaust apparatus according to claim 1 , wherein the strut shield is directly attached to the respective duct-wall for a remaining length of the perimeter of the strut shield at the respective interface.

4. The exhaust apparatus according to claim 1 , wherein said at least one collar comprises one or both of:
a leading edge collar extending around a leading edge of the strut shield at the respective interface, and
a trailing edge collar extending around a trailing edge of the strut shield at the respective interface.

5. The exhaust apparatus according to claim 4 , wherein both the first interface and the second interface comprise a respective leading edge collar and a respective trailing edge collar.

6. The exhaust apparatus according to claim 1 , wherein the first joint and the second joint each comprises a weld joint.

7. The exhaust apparatus according to claim 1 , wherein the collar extends partially along the perimeter of the strut shield at the respective interface from a first end to a second end of the collar,
wherein the radius of the intersection varies continuously between the first and second ends.

8. The exhaust apparatus according to claim 7 , wherein a maximum radius of the intersection is located at a location between the first and second ends.

9. The exhaust apparatus according to claim 8 , wherein the maximum radius is located at a leading edge or at a trailing edge of the strut shield.

10. The exhaust apparatus according to claim 8 , wherein the maximum radius of the intersection is configured such that:
a ratio of a span-wise height of the strut shield at the location of the maximum radius to the maximum radius lies in the range of 7-16, and/or
a ratio of the maximum radius to a material thickness of the strut shield lies in the range of 4-10.

11. The exhaust apparatus according to claim 7 , wherein the radius of the intersection at the first end and the radius of the intersection at the second end of the collar are configured to respectively match the radius of a joint between the strut shield and the respective duct-wall adjacent to the first end and a radius of a joint between the strut shield and the respective duct-wall adjacent to the second end.

12. The exhaust diffuser according to claim 1 , wherein the smooth curve forming the intersection is defined by an inner radius on a first surface facing a flowpath and an outer radius on a second surface opposite to the first surface.

13. The exhaust diffuser according to claim 1 , wherein the at least one collar extends around a trailing edge of the strut shield at the first interface, and wherein an aft end of the collar comprises a radially extending flange provided with bolt holes for attachment to a downstream exhaust manifold.

14. A method for servicing a gas turbine to mitigate cracking in an exhaust apparatus of the gas turbine engine,
the exhaust apparatus comprising:
an annular duct extending axially along a machine axis of the gas turbine, the annular duct being radially delimited by an outer duct-wall and an inner duct-wall,
a plurality of struts, which are circumferentially distributed within the annular duct, wherein each strut extends at least from the outer duct-wall to the inner duct-wall and is encapsulated in a respective strut shield,
wherein each strut shield engages with the outer duct-wall along a first interface and engages with the inner duct-wall along a second interface,

the method comprising:
attaching at least one collar at the first interface and/or at the second interface, wherein after attachment, the collar extends along a partial length of the perimeter of the strut shield at the respective interface, wherein the collar comprises a first section and a second section oriented at an angle to the first section,
wherein attaching the collar comprises:
aligning the first section with the strut shield and aligning the second section with the respective duct-wall, and
joining the first section to the strut shield along a first joint and joining the second section to the respective duct-wall along a second joint,

wherein an intersection of the first and second sections is formed by a smooth curve defined by a radius configured to distribute stresses at the respective interface.

15. The method according to claim 14 , wherein the joining of the first section to the strut shield and the joining of the second section to the respective duct-wall comprise welding.

16. The method according to claim 14 , comprising:
prior to said attaching of the at least one collar, forming a cutout in part on the strut shield and in part on the respective duct-wall, such that a peripheral contour of the cutout as a whole corresponds to a peripheral contour of the collar.

17. The method according to claim 16 , wherein the cutout is formed by a machining operation.

Assignees

• Siemens Ag

Inventors

• Maurya Shashikant
• Giaimo John
• Wiebe Ryan David
• Nickols Keith L
• Correa Andre

Classifications

• F01D9/06

  Fluid supply conduits to nozzles or the like · CPC title

• F01D25/30

  Exhaust heads, chambers, or the like · CPC title

• F05D2230/232

  by welding · CPC title

• F05D2240/14

  Casings or housings protecting or supporting assemblies within · CPC title

• F01D9/065 Primary

  Fluid supply or removal conduits traversing the working fluid flow, e.g. for lubrication-, cooling-, or sealing fluids (see also F01D25/16, F01D25/24 and F01D25/26) · CPC title