US-12618342-B1 - Turbine exhaust case with stiffening brace

Abstract

An exhaust system for an aircraft engine, has: an exhaust case extending around a central axis and defining openings; exhaust ports secured to the exhaust case and being in register with the openings and protruding away from the exhaust case in a direction having a radial component relative to the central axis, the exhaust ports extending circumferentially around port axes being transverse to the central axis; a turbine exhaust duct (TED) having an annular inlet conduit extending around the central axis for directing combustion gases in an axial direction, and outlet conduits fluidly communicating with the annular inlet conduit and extending generally radially outwardly relative to the annular inlet conduit, the outlet conduits communicating with the openings of the exhaust case and with the exhaust ports; and stiffening braces secured to the exhaust ports and extending across the exhaust ports and in a direction being transverse to the port axes.

Inventors

• Lorenzo SANZARI
• Remy Synnott

Assignees

• PRATT & WHITNEY CANADA CORP.

Dates

Publication Date

20260505

Application Date

20250507

Claims (20)

1. 1 . An exhaust system for an aircraft engine, comprising: an exhaust case extending around a central axis and axially between a forward end and a rearward end, the exhaust case defining openings between the forward end and the rearward end; exhaust ports secured to the exhaust case and being in register with the openings, the exhaust ports protruding away from the exhaust case in a direction having a radial component relative to the central axis, the exhaust ports extending circumferentially around port axes being transverse to the central axis; a turbine exhaust duct (TED) having an annular inlet conduit extending around the central axis for directing combustion gases in an axial direction, and outlet conduits fluidly communicating with the annular inlet conduit and extending generally radially outwardly relative to the annular inlet conduit, the outlet conduits communicating with the openings of the exhaust case and with the exhaust ports; and stiffening braces secured to the exhaust ports and extending across the exhaust ports and in a direction being transverse to the port axes.
2. 2 . The exhaust system of claim 1 , wherein the stiffening braces intersect the port axes.
3. 3 . The exhaust system of claim 1 , wherein the stiffening braces extend along spans from first ends to second ends both secured to the exhaust ports, the stiffening braces having cross-sectional areas taken on planes being normal to the spans, the cross-sectional areas being airfoil-shaped.
4. 4 . The exhaust system of claim 3 , wherein the cross-sectional areas are symmetrical.
5. 5 . The exhaust system of claim 3 , wherein the stiffening braces twist along the spans such that angle of attacks defined with the combustion gases vary along the spans.
6. 6 . The exhaust system of claim 1 , wherein the stiffening braces extend from leading edges to trailing edges being downstream of the leading edges relative to a direction of the combustion gases, the stiffening braces having chords extending from the leading edges to the trailing edges, the chords being angled to be parallel to a flow direction of exhaust gases exiting the exhaust ports.
7. 7 . The exhaust system of claim 1 , wherein the stiffening braces extend from first ends to second ends along spans, the spans being angled at about 45 degrees relative to the central axis of the exhaust case.
8. 8 . The exhaust system of claim 1 , comprising temperature probes mounted to the stiffening braces, the probes distributed along spans of the stiffening braces.
9. 9 . The exhaust system of claim 1 , wherein a stiffening brace of the stiffening braces includes a first flange at a first end of the stiffening brace and a second flange at a second end of the stiffening brace, the first flange and the second flange being secured to an exhaust port of the exhaust ports.
10. 10 . The exhaust system of claim 1 , wherein the stiffening braces are secured to the exhaust ports and are free from intersection with the outlet conduits of the TED.
11. 11 . 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 sectioned, 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 extending around the central axis and axially between a forward end and a rearward end, the exhaust case defining openings between the forward end and the rearward end; exhaust ports secured to the exhaust case and being in register with the openings, the exhaust ports protruding away from the exhaust case in a direction having a radial component relative to the central axis, the exhaust ports extending circumferentially around port axes being transverse to the central axis; a turbine exhaust duct (TED) having an annular inlet conduit extending around the central axis for directing combustion gases in an axial direction, and outlet conduits fluidly communicating with the annular inlet conduit and extending generally radially outwardly relative to the annular inlet conduit, the outlet conduits communicating with the openings of the exhaust case and with the exhaust ports; and stiffening braces secured to the exhaust ports at opposite locations on the exhaust ports, the stiffening braces extending across the exhaust ports transversally to the port axes.
12. 12 . The reverse-flow gas turbine engine of claim 11 , wherein the stiffening braces intersect the port axes.
13. 13 . The reverse-flow gas turbine engine of claim 11 , wherein the stiffening braces extend along spans from first ends to second ends both secured to the exhaust ports, the stiffening braces having cross-sectional areas taken on planes being normal to the spans, the cross-sectional areas being airfoil-shaped.
14. 14 . The reverse-flow gas turbine engine of claim 13 , wherein the cross-sectional areas are symmetrical.
15. 15 . The reverse-flow gas turbine engine of claim 13 , wherein the stiffening braces twist along the spans such that angle of attacks defined with the combustion gases vary along the spans.
16. 16 . The reverse-flow gas turbine engine of claim 11 , wherein the stiffening braces extend from leading edges to trailing edges being downstream of the leading edges relative to a direction of the combustion gases, the stiffening braces having chords extending from the leading edges to the trailing edges, the chords being angled to be parallel to a flow direction of exhaust gases exiting the exhaust ports.
17. 17 . The reverse-flow gas turbine engine of claim 11 , wherein the stiffening braces extend from first ends to second ends along spans, the spans being angled at about 45 degrees relative to the central axis of the exhaust case.
18. 18 . The reverse-flow gas turbine engine of claim 11 , comprising temperature probes embedded in the stiffening braces, the probes distributed along spans of the stiffening braces.
19. 19 . The reverse-flow gas turbine engine of claim 11 , wherein a stiffening brace of the stiffening braces include a first flange at a first end of the stiffening brace and a second flange at a second end of the stiffening brace, the first flange and the second flange being secured to an exhaust port of the exhaust ports.
20. 20 . The reverse-flow gas turbine engine of claim 11 , wherein the stiffening braces are secured to the exhaust ports and are free from intersection with the outlet conduits of the TED.

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. In some configurations, the exhaust ducts structurally supports other components of aircraft engines. Existing exhaust ducts are satisfactory, but improvements are sought. SUMMARY In one aspect, there is provided an exhaust system for an aircraft engine, comprising: an exhaust case extending around a central axis and axially between a forward end and a rearward end, the exhaust case defining openings between the forward end and the rearward end; exhaust ports secured to the exhaust case and being in register with the openings, the exhaust ports protruding away from the exhaust case in a direction having a radial component relative to the central axis, the exhaust ports extending circumferentially around port axes being transverse to the central axis; a turbine exhaust duct (TED) having an annular inlet conduit extending around the central axis for directing combustion gases in an axial direction, and outlet conduits fluidly communicating with the annular inlet conduit and extending generally radially outwardly relative to the annular inlet conduit, the outlet conduits communicating with the openings of the exhaust case and with the exhaust ports; and stiffening braces secured to the exhaust ports and extending across the exhaust ports and in a direction being transverse to the port axes. The exhaust system described above may include any of the following features, in any combinations. In some embodiments, the stiffening braces intersect the port axes. In some embodiments, the stiffening braces extend along spans from first ends to second ends both secured to the exhaust ports, the stiffening braces having cross-sectional areas taken on planes being normal to the spans, the cross-sectional areas being airfoil-shaped. In some embodiments, the cross-sectional areas are symmetrical. In some embodiments, the stiffening braces twist along the spans such that angle of attacks defined with the combustion gases vary along the spans. In some embodiments, the stiffening braces extend from leading edges to trailing edges being downstream of the leading edges relative to a direction of the combustion gases, the stiffening braces having chords extending from the leading edges to the trailing edges, the chords being angled to be parallel to a flow direction of exhaust gases exiting the exhaust ports. In some embodiments, the stiffening braces extend from first ends to second ends along spans, the spans being angled at about 45 degrees relative to the central axis of the exhaust case. In some embodiments, temperature probes are mounted to the stiffening braces, the probes distributed along spans of the stiffening braces. In some embodiments, a stiffening brace of the stiffening braces includes a first flange at a first end of the stiffening brace and a second flange at a second end of the stiffening brace, the first flange and the second flange being secured to an exhaust port of the exhaust ports. In some embodiments, the stiffening braces are secured to the exhaust ports and are free from intersection with the outlet conduits of the TED. 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; exhaust ports secured to the exhaust case and being in register with the openings, the exhaust ports protruding away from the exhaust case in a direction having a radial component relative to the central axis, the exhaust ports extending circumferentially around port axes being transverse to the central axis; a turbine exhaust duct (TED) having an annular inlet conduit extending around the central axis for directing combustion gases in an axial direction, and outlet conduits fluidly communicating with the annular inlet conduit and extending generally radially outwardly relative to the annular inlet conduit, the outlet conduits communicating with the openings of the exhaust case and with the exhaust ports; and stiffening braces secured to the exhaust ports at opposite locations on the exhaust ports. The reverse-flow gas turbine engine described above may include any of the following features, in any combinations. In some embodiments, the stiffening braces intersect the port axes. In some embodiments, the stiffening braces extend along spans from first ends to second ends both secured to the exhaust ports, the stiffening braces having cross-