US-12617541-B1 - Exhaust case for aircraft engine

Abstract

An exhaust system, has: a turbine exhaust duct (TED) having an annular inlet conduit extending around a central axis, and outlet conduits fluidly communicating with the annular inlet conduit and extending generally radially outward relative to the annular inlet conduit; and an exhaust case surrounding the TED, the exhaust case having openings, each of the outlet conduits received through a respective one of the openings; and exhaust conduits secured to the exhaust case and each extending around a respective one of the openings of the exhaust case, an exhaust conduit of the exhaust conduits including: a duct protruding away from the exhaust case and fluidly communicating with a respective one of the outlet conduits; a flange flaring away from the duct, the exhaust conduit secured to the exhaust case via the flange; and a stiffener protruding transversally from the flange, the flange located between the duct and the stiffener.

Inventors

• Guy Lefebvre
• Francois DOYON

Assignees

• PRATT & WHITNEY CANADA CORP.

Dates

Publication Date

20260505

Application Date

20241219

Claims (19)

1. 1 . An exhaust system for an aircraft engine, comprising: a turbine exhaust duct (TED) having an annular inlet conduit extending around a central axis for directing combustion gases generally in an axial direction, and outlet conduits fluidly communicating with the annular inlet conduit and extending generally radially outward relative to the annular inlet conduit; and an exhaust case surrounding the TED, the exhaust case having openings, each of the outlet conduits received through a respective one of the openings; and exhaust conduits secured to the exhaust case and each extending around a respective one of the openings of the exhaust case, an exhaust conduit of the exhaust conduits including: a duct protruding away from the exhaust case and fluidly communicating with a respective one of the outlet conduits; a flange flaring away from the duct, the exhaust conduit secured to the exhaust case via the flange; and a stiffener protruding transversally from the flange, the flange located between the duct and the stiffener.
2. 2 . The exhaust system of claim 1 , wherein the stiffener defines an angle with the flange, the angle being at least about 90 degrees.
3. 3 . The exhaust system of claim 1 , wherein the stiffener has a height taken along a conduit axis of the exhaust conduit, the height being less than that of the duct.
4. 4 . The exhaust system of claim 1 , wherein the stiffener extends around the duct from a first end to a second end, a gap defined between the first end and the second end, the gap being free of the stiffener.
5. 5 . The exhaust system of claim 4 , wherein the gap is aligned with a closest location between the flange and a mounting flange of the exhaust case.
6. 6 . The exhaust system of claim 1 , wherein a weld or braze joint is located between the flange and the exhaust case.
7. 7 . The exhaust system of claim 6 , wherein the weld or braze joint extends a full periphery of the respective one of the openings.
8. 8 . The exhaust system of claim 1 , wherein a thickness of the stiffener is greater than a thickness of the duct.
9. 9 . The exhaust system of claim 1 , wherein the stiffener, the duct, and the flange are parts of a single monolithic body of the exhaust conduit.
10. 10 . A reverse-flow gas turbine engine, comprising: an outer case assembly extending around a central axis and enclosing a core, the core including a compressor section, a combustor, and a turbine section, the turbine section located forward of the combustor and of the compressor section relative to a direction of travel of the reverse-flow gas turbine engine, the outer case assembly including an exhaust case defining openings; and a turbine exhaust duct (TED) having an annular inlet conduit extending around the central axis for directing combustion gases generally in an axial direction and outlet conduits communicating with the annular inlet conduit and extending generally radially outward relative to the annular inlet conduit; and exhaust conduits secured to the exhaust case and each extending around a respective one of the openings of the exhaust case, the exhaust conduits secured to the exhaust case via flanges thereof, the exhaust conduits further including stiffening lips extending transversally to the exhaust case and extending at least partially around the openings.
11. 11 . The reverse-flow gas turbine engine of claim 10 , wherein each of the stiffening lips defines an angle with a respective one of the flanges, the angle being at least 90 degrees.
12. 12 . The reverse-flow gas turbine engine of claim 10 , wherein each of the stiffening lips has a height taken along a conduit axis a respective one of the exhaust conduits, the height being less an overall height of the respective one of exhaust conduits.
13. 13 . The reverse-flow gas turbine engine of claim 10 , wherein the stiffening lips extend around the openings from first ends to second ends, gaps defined between the first ends and the second ends, the gaps being free of the stiffening lips.
14. 14 . The reverse-flow gas turbine engine of claim 13 , wherein the gaps are aligned with closest locations between the flanges and a mounting flange of the exhaust case.
15. 15 . The reverse-flow gas turbine engine of claim 10 , wherein weld or braze joints are located between the flanges and the exhaust case.
16. 16 . The reverse-flow gas turbine engine of claim 15 , wherein the weld or braze joints extend full peripheries of the openings.
17. 17 . The reverse-flow gas turbine engine of claim 10 , wherein a thickness of the stiffening lips is greater than a thickness of a duct of the exhaust conduit.
18. 18 . The reverse-flow gas turbine engine of claim 10 , wherein the exhaust conduits include ducts, the flanges, and the stiffening lips, the ducts, the flanges and the stiffener being parts of monolithic arts of the exhaust conduits.
19. 19 . The reverse-flow gas turbine engine of claim 10 , wherein portions of the outlet conduits extend inside the exhaust conduits.

Description

TECHNICAL FIELD The application relates generally to aircraft engines and, more particularly, to exhaust cases of such engines. BACKGROUND Exhaust ducts are disposed downstream of turbine sections and are configured for evacuating combustion gases that have been used to power the turbine sections. These combustion gases are hot and care should be taken to ensure that the exhaust ducts sustain these harsh conditions. Existing exhaust ducts are satisfactory to some extend, but improvements are always sought. SUMMARY In one aspect, there is provided an exhaust system for an aircraft engine, comprising: a turbine exhaust duct (TED) having an annular inlet conduit extending around a central axis for directing combustion gases generally in an axial direction, and outlet conduits fluidly communicating with the annular inlet conduit and extending generally radially outward relative to the annular inlet conduit; and an exhaust case surrounding the TED, the exhaust case having openings, each of the outlet conduits received through a respective one of the openings; and exhaust conduits secured to the exhaust case and each extending around a respective one of the openings of the exhaust case, an exhaust conduit of the exhaust conduits including: a duct protruding away from the exhaust case and fluidly communicating with a respective one of the outlet conduits; a flange flaring away from the duct, the exhaust conduit secured to the exhaust case via the flange; and a stiffener protruding transversally from the flange, the flange located between the duct and the stiffener. The exhaust system described above may include any of the following features, in any combinations. In some embodiments, the stiffener defines an angle with the flange, the angle being at least about 90 degrees. In some embodiments, the stiffener has a height taken along a conduit axis of the exhaust conduit, the height being less than that of the duct. In some embodiments, the stiffener extends around the duct from a first end to a second end, a gap defined between the first end and the second end, the gap being free of the stiffener. In some embodiments, the gap is aligned with a closest location between the flange and a mounting flange of the exhaust case. In some embodiments, a weld or braze joint is located between the flange and the exhaust case. In some embodiments, the weld or braze joint extends a full periphery of the respective one of the openings. In some embodiments, a thickness of the stiffener is greater than a thickness of the duct. In some embodiments, the stiffener, the duct, and the flange are parts of a single monolithic body of the exhaust conduit. In some embodiments, a portion of a respective one of the outlet conduits extends inside the duct. In another aspect, there is provided a reverse-flow gas turbine engine, comprising: an outer case assembly extending around a central axis and enclosing a core, the core including a compressor section, a combustor, and a turbine section, the turbine section located forward of the combustor and of the compressor section relative to a direction of travel of the reverse-flow gas turbine engine, the outer case assembly including an exhaust case defining openings; and a turbine exhaust duct (TED) having an annular inlet conduit extending around the central axis for directing combustion gases generally in an axial direction and outlet conduits communicating with the annular inlet conduit and extending generally radially outward relative to the annular inlet conduit; and exhaust conduits secured to the exhaust case and each extending around a respective one of the openings of the exhaust case, the exhaust conduits secured to the exhaust case via flanges thereof, the exhaust conduits further including stiffening lips extending transversally to the exhaust case and extending at least partially around the openings. The reverse-flow gas turbine engine described above may include any of the following features, in any combinations. In some embodiments, the stiffening lips define an angle with the flange, the angle being at least 90 degrees. In some embodiments, the stiffening lips have a height taken along a conduit axis of the exhaust conduit, the height being less an overall height of the exhaust conduit. In some embodiments, the stiffening lips extend around the openings from first ends to second ends, gaps defined between the first ends and the second ends, the gaps being free of the stiffening lips. In some embodiments, the gaps are aligned with closest locations between the flanges and a mounting flange of the exhaust case. In some embodiments, weld or braze joints are located between the flanges and the exhaust case. In some embodiments, the weld or braze joints extend full peripheries of the openings. In some embodiments, a thickness of the stiffening lips is greater than a thickness of a duct of the exhaust conduit. In some embodiments, the exhaust conduits include ducts, the flanges, and the sti