초록 ▼

A turbine exhaust case for a gas turbine engine has an outer shroud and an inner shroud concentrically defining therebetween an annular gaspath for channelling hot gases. A plurality of circumferentially spaced-apart turbine exhaust struts extends radially across the hot gaspath. The inner shroud ma

A turbine exhaust case for a gas turbine engine has an outer shroud and an inner shroud concentrically defining therebetween an annular gaspath for channelling hot gases. A plurality of circumferentially spaced-apart turbine exhaust struts extends radially across the hot gaspath. The inner shroud may be provided in the form of an acoustic panel. The acoustic panel has a radially outwardly facing surface defining the radially inner flow boundary surface of the gaspath. The acoustic panel is mechanically fastened to the radially inner end of the struts.

대표청구항 ▼

1. A turbine exhaust case disposed downstream of a last stage of turbine blades of a gas turbine for exhausting hot gases to the atmosphere, the engine having an axis, the exhaust case comprising a radially outer annular shroud and a radially inner annular shroud concentrically mounted about said ax

1. A turbine exhaust case disposed downstream of a last stage of turbine blades of a gas turbine for exhausting hot gases to the atmosphere, the engine having an axis, the exhaust case comprising a radially outer annular shroud and a radially inner annular shroud concentrically mounted about said axis and defining therebetween an annular gaspath for channeling hot gases received from the last stage of turbine blades of the engine, a plurality of circumferentially spaced-apart struts extending radially across the gaspath between the radially outer and the radially inner annular shrouds, at least one of said radially inner and outer shrouds being defined by at least one arcuate acoustic panel, said at least one arcuate acoustic panel having a radially facing surface defining a flow boundary surface of said gaspath, the at least one arcuate acoustic panel having an acoustic treatment including a core layer of cellular honeycomb like material and a plurality of acoustic holes defined in the radially facing surface defining the flow boundary surface, said at least one acoustic panel having an array of circumferentially spaced-apart fastener receiving holes extending thicknesswise therethrough, each of said fastener receiving holes being aligned with a corresponding connection hole defined in an end wall of an associated one of said struts, and a plurality of fasteners projecting radially from said fastener receiving holes of said at least one acoustic panel into said connection holes of said struts, the fasteners structurally connecting the struts to said at least one acoustic panel. 2. The turbine exhaust case defined in claim 1, wherein each said fastener includes a bolt threadably engaged into said connection hole of a corresponding one of said struts. 3. The turbine exhaust case defined in claim 1, wherein each said fastener includes a bolt having a threaded shank and a head, the head of said bolt bearing against a radially inwardly facing side of the at last one acoustic panel, the radially inner shroud being defined by said at least one acoustic panel. 4. The turbine exhaust case defined in claim 1, wherein each of said fastener receiving holes comprises a passage defined in a tubular insert integrated to said at least one acoustic panel. 5. The turbine exhaust case defined in claim 1, wherein said at least one acoustic panel comprises a plurality of circumferentially adjoining acoustic panels which collectively form the radially inner annular shroud, at least one struts being structurally connected to each of said plurality of acoustic panels. 6. The turbine exhaust case defined in claim 1, wherein said at least one acoustic panel comprises a frameless assembly of circumferentially adjoining acoustic panels, said frameless assembly of circumferentially adjoining acoustic panels forming said radially inner annular shroud, said acoustic panels being structurally supported in a ring like configuration by said struts and without any other underlying supporting structure. 7. A turbine exhaust case for disposed downstream of a last stage of turbine blades of a turbo fan engine for exhausting hot gases to the atmosphere, the engine having an axis, the exhaust case comprising a radially outer annular shroud and a radially inner annular shroud concentrically mounted about said axis and defining therebetween an annular gaspath for channeling hot gases received from the last stage of turbine blades of the engine, a plurality of circumferentially spaced-apart turbine exhaust struts extending radially across the gaspath between the radially outer and the radially inner annular shrouds, the radially inner shroud being defined by at least one arcuate acoustic panel, having an acoustic treatment including a core layer of cellular honeycomb like material, said at least one arcuate acoustic panel having a radially outwardly facing surface defining a radially inner flow boundary surface of said gaspath, said radially outwardly facing surface having a plurality of acoustic holes defined therein, said exhaust struts projecting radially outwardly from said radially outwardly facing surface of the at least one acoustic panel and being mechanically fastened at their radially inner ends to said at least one acoustic panel. 8. The turbine exhaust case defined in claim 7, wherein the exhaust struts have radially outer ends, and wherein said radially outer ends are welded to said radially outer annular shroud. 9. The turbine exhaust case defined in claim 7, wherein said at least one acoustic panel is only supported from a radially outer side thereof, the exhaust struts supporting all the weight of said at least one acoustic panel. 10. The turbine exhaust case defined in claim 7, wherein the at least one acoustic panel projects axially rearwardly from the exhaust struts in a cantilever fashion. 11. The turbine exhaust case defined in claim 7, wherein said radially inner ends of said struts each comprise a radially inwardly facing end wall defining at least one threaded hole for threading engagement with a threaded fastener extending thicknesswise through said at least one acoustic panel. 12. The turbine exhaust case defined in claim 11, wherein said threaded fastener comprises a bolt engaged with a tubular insert integrated to said at least one acoustic panel. 13. The turbine exhaust case defined in claim 12, wherein said bolt has a threaded shank projecting radially outwardly from the radially outwardly facing surface of the at least one acoustic panel. 14. A method of manufacturing a turbine exhaust case configured for mounting downstream of a last stage of turbine blades of a gas turbine engine, the method comprising: a) providing a radially outer annular shroud, b) structurally mounting a circumferential array of struts to a radially inwardly facing surface of the radially outer shroud, and then c) mechanically fastening individual acoustic panels to a radially inner end of the struts, the acoustic panels collectively forming a circumferentially segmented radially inner annular shroud, each individual acoustic panel having a radially outwardly facing surface defining a plurality of acoustic holes and a core layer of cellular honeycomb like material. 15. A method as defined in claim 14, wherein step c) comprises bolting the acoustic panels to the struts. 16. A method as defined in claim 14, wherein step c) comprises cantilevering the acoustic panels from said struts. 17. A method as defined in claim 14, wherein step c) comprises inserting a bolt from a radially inner side of the acoustic panels in each of a plurality of tubular inserts integrated to the acoustic panels, and threadably engaging the bolt in threaded hole defined in a radially inwardly facing end wall of each strut.