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A turbine exhaust casing having an outer casing, an inner casing, an annular exhaust gas path defined between outer and inner flow path walls, and a turbine exhaust casing cavity located radially outward and radially inward from the gas path. A plurality of structural struts support the inner casing

A turbine exhaust casing having an outer casing, an inner casing, an annular exhaust gas path defined between outer and inner flow path walls, and a turbine exhaust casing cavity located radially outward and radially inward from the gas path. A plurality of structural struts support the inner casing to the outer casing, and a fairing surrounds each of the struts in an area extending between the outer and inner flow path walls. A first purge air path extends through at least one of the struts for conducting purge cooling air radially inward to the inner casing, and a second purge air path extends through the strut for further conducting the purge cooling air radially outward to provide a flow of purge air to a location of the exhaust casing cavity radially outward from the outer flow path wall.

대표청구항 ▼

1. A turbine assembly in a turbine engine, the turbine assembly having an outer casing, an inner casing, an annular exhaust gas path defined between outer and inner flow path walls, and a turbine exhaust casing cavity located radially outward and radially inward from the gas path, and further compri

1. A turbine assembly in a turbine engine, the turbine assembly having an outer casing, an inner casing, an annular exhaust gas path defined between outer and inner flow path walls, and a turbine exhaust casing cavity located radially outward and radially inward from the gas path, and further comprising: a plurality of structural struts supporting the inner casing to the outer casing;a fairing surrounding each of the struts in an area extending between the outer and inner flow path walls;a first purge air path extending radially inward through at least one of the struts conducting purge cooling air to the inner casing for supplying purge air to at least one component radially inward from the inner casing; anda second purge air path extending radially outward through the at least one of the struts for further conducting the purge cooling air radially outward from the at least one component to provide a flow of purge air to an outer location of the exhaust casing cavity radially outward from the outer flow path wall. 2. The turbine assembly of claim 1, wherein the first purge air path is formed by a tubular passage extending through a central portion of the at least one of the struts. 3. The turbine assembly of claim 2, wherein the second purge air path is formed by an open cavity extending radially between radially outer and inner ends of the at least one of the struts, and the tubular passage extends through the open cavity. 4. The turbine assembly of claim 3, wherein the open cavity is elongated in an axial direction parallel to the gas path, and including strut orifices extending through axially extending sides of the at least one of the struts from the open cavity to an area exterior of the strut and isolated from the exhaust gas path. 5. The turbine assembly of claim 4, wherein the strut orifices are located adjacent to the radially outer end of the at least one of the struts, and including a strut shield surrounding an outer surface of the at least one of the struts, and defining a gap therebetween, for guiding a flow of the purge air from the strut orifices radially inward along the outer surface of the at least one of the struts. 6. The turbine assembly of claim 5, including an exit orifice at a radially inner end of the strut shield for providing a controlled flow of the purge air from the second purge air path into an inner location of the exhaust casing cavity radially inward from the inner flow path wall. 7. The turbine assembly of claim 6, wherein the exit orifice extends axially downstream from the open cavity within the at least one of the struts adjacent to the inner casing. 8. The turbine assembly of claim 3, including an oil line extending through the first purge air path, the oil line extending radially inward to a bearing compartment for a rear bearing of the turbine engine. 9. The turbine assembly of claim 1, wherein air exiting the first purge air path provides seal pressure air exterior to a seal between a bearing compartment housing and a rotor shaft of the turbine engine. 10. The turbine assembly of claim 9, including a chamber located between the inner casing and the bearing compartment housing where the seal pressure air mixes with bleed air from a radially inner cooling air cavity of a turbine stage for the turbine engine and flows radially outward to an entry to the second purge air path at the inner casing. 11. The turbine assembly of claim 1, including a connecting purge air path located between the at least one of the struts and the fairing, and extending between the outer and inner flow path walls, for conducting the purge air delivered to the outer location of the exhaust casing cavity from the second purge air path radially inward to an inner location of the exhaust casing cavity radially inward from the inner flow path wall. 12. The turbine assembly of claim 1, wherein the struts are removable members attached to the outer and inner casings at detachable fastener connections. 13. The turbine assembly of claim 1, wherein the outer casing defines an intermediate turbine casing between a core engine turbine and a power turbine. 14. A turbine assembly in a turbine engine, the turbine assembly having an outer casing, an inner casing, an annular exhaust gas path defined between outer and inner flow path walls, and a turbine exhaust casing cavity located radially outward and radially inward from the gas path, and further comprising: a plurality of struts extending between the inner casing and the outer casing;a first purge air path extending radially inward through at least one of the struts conducting purge air to the inner casing for supplying purge air to at least one component radially inward from the inner casing; anda second purge air path having an inlet located at the inner casing and extending radially outward through the at least one of the struts for further conducting the purge cooling air radially outward to provide a flow of purge air to an outer location of the exhaust casing cavity radially outward from the outer flow path wall;wherein the at least one of the struts includes opposing axially extending side walls, the opposing side walls defining a cavity forming the second purge air path therebetween, and including strut orifices defined through the side walls for flow of the purge air out of the at least one of the struts. 15. The turbine assembly of claim 14, including a passage extending axially forward in the turbine engine conducting the purge air exiting from the first purge air path to a location adjacent a turbine stage cooling cavity, where the purge air mixes with air from the turbine stage cooling cavity, and including a chamber conducting purge air axially rearward to an inlet to the second purge air path. 16. The turbine assembly of claim 15, wherein the first purge air path is supplied with purge air from a first supply location in a compressor section of the turbine engine, and the turbine stage cooling cavity is supplied with cooling air from a second supply location of the compressor section different from the first supply location. 17. The turbine assembly of claim 14, wherein a portion of the purge air exiting the second purge air path feeds purge air to a connecting purge air path extending radially inward through a fairing surrounding the at least one of the struts. 18. The turbine assembly of claim 17, wherein a portion of the purge air exiting the second purge air path feeds purge air in an axially forward direction to a location of a seal between a turbine ring segment and the outer flow path wall. 19. The turbine assembly of claim 14, wherein the strut orifices are defined through the side walls at locations radially outward from the outer flow path wall. 20. A turbine assembly in a turbine engine, the turbine assembly having an outer casing, an inner casing, an annular exhaust gas path defined between outer and inner flow path walls, and a turbine exhaust casing cavity located radially outward and radially inward from the gas path, and further comprising: a plurality of struts extending between the inner casing and the outer casing;a first purge air path extending radially inward through at least one of the struts conducting purge air to the inner casing for supplying purge air to at least one component radially inward from the inner casing;a second purge air path having an inlet located at the inner casing and extending radially outward through the at least one of the struts for further conducting the purge cooling air radially outward to provide a flow of purge air to an outer location of the exhaust casing cavity radially outward from the outer flow path wall; andincluding a passage extending axially forward in the turbine engine conducting the purge air exiting from the first purge air path to a location adjacent a turbine stage cooling cavity, where the purge air mixes with air from the turbine stage cooling cavity, and including a chamber conducting purge air axially rearward to an inlet to the second purge air path.