초록 ▼

The gas turbine engine has a bleed air aperture formed in the radially outer wall upstream from the combustor and a bearing cavity formed within the radially inner wall, at least two bearing seals enclosing at least one bearing in the bearing cavity and separating the bearing cavity from associated

The gas turbine engine has a bleed air aperture formed in the radially outer wall upstream from the combustor and a bearing cavity formed within the radially inner wall, at least two bearing seals enclosing at least one bearing in the bearing cavity and separating the bearing cavity from associated buffer air entry points, an oil supply system including oil paths leading to each of the bearings; a buffer air supply system including buffer air paths leading to each of the entry points and a baffle partitioning one of the entry points.

대표청구항 ▼

1. A gas turbine engine having an annular gas path between a radially outer wall and a radially inner wall, leading successively across at least one compressor stage, a combustor section, and at least one turbine stage, the gas turbine engine comprising: a bleed air aperture in the radially outer wa

1. A gas turbine engine having an annular gas path between a radially outer wall and a radially inner wall, leading successively across at least one compressor stage, a combustor section, and at least one turbine stage, the gas turbine engine comprising: a bleed air aperture in the radially outer wall upstream from the combustor, the bleed air aperture drawing pressurized bleed air from the at least one compressor stage which is carried along a bleed air path, at least a portion of the pressurized bleed air being used for pressurizing an aircraft cabin;a bearing cavity formed within the radially inner wall, having at least one bearing therein rotatably supporting at least one shaft of the gas turbine engine, at least two bearing seals enclosing the at least one bearing in the bearing cavity and separating the bearing cavity from at least one buffer air entry point, and at least one scavenge passage inlet in the bearing cavity;an oil supply system including at least one oil path leading to the at least one bearing;a buffer air supply system including at least one buffer air path leading to the at least one buffer air entry point; anda baffle extending across the at least one buffer air path and partitioning said buffer air path into first and second portions, the first portion being upstream of the second portion relative to normal flow through the at least one buffer air path during normal flow conditions of the gas turbine engine, the first portion communicating with the at least one buffer air entry point and a secondary path flowing to a portion of the gas path upstream of the bleed air aperture relative to normal flow through the gas path during normal flow conditions of the gas turbine engine, the secondary path being downstream of the baffle relative to the normal flow through the gas path during normal flow conditions of the gas turbine engine, a first flow restrictor being disposed within the secondary path, the second portion being exposed to one of the at least two bearing seals and communicating with a deviation path flowing to a deviation outlet separate from the portion of the gas path upstream of the bleed air aperture, the deviation path having a second flow restrictor sized to maintain flow from the first portion toward the second portion across the baffle and from the second portion toward the bearing cavity across the bearing seal during normal flow conditions of the gas turbine engine, said baffle guiding fluid within the second portion through the deviation path, upon flow reversal. 2. The gas turbine engine of claim 1 wherein the deviation path extends inside at least one of said at least one shaft. 3. The gas turbine engine of claim 2 wherein the gas turbine engine has two shafts, and the deviation path extends at least partially along an intershaft spacing between the two shafts. 4. The gas turbine engine of claim 2 wherein the baffle has a baffle member and a lab seal protruding outwardly from said at least one shaft. 5. The gas turbine engine of claim 1, wherein the second portion forms a subchamber portion, the subchamber portion includes an outer gutter. 6. The gas turbine engine of claim 5 wherein the outer gutter is formed at least partially by the baffle having a radially-extending section connected to an axially sloping portion by a corner. 7. The gas turbine engine of claim 1, wherein the second portion forms a subchamber portion, the subchamber portion includes an inner gutter formed in the at least one shaft. 8. The gas turbine engine of claim 7 wherein the inner gutter includes an annular outward protrusion formed in the at least one shaft. 9. The gas turbine engine of claim 8 wherein the annular outward protrusion is radially aligned with an axially sloping portion of a baffle member of the baffle, the baffle member at least partially forming an outer gutter. 10. The gas turbine engine of claim 9 wherein the baffle includes a seal extending between the at least one shaft and the baffle, the seal being positioned adjacent the annular outward protrusion. 11. A gas turbine engine having an annular gas path between a radially outer wall and a radially inner wall and leading successively across at least one compressor stage, a combustor section, and at least one turbine stage, the gas turbine engine comprising: a bleed air aperture in the radially outer wall upstream from the combustor;a bearing cavity formed within the radially inner wall to the gas path, having at least one bearing therein rotatably supporting at least one shaft of the gas turbine engine, at least two bearing seals enclosing the at least one bearing in the bearing cavity and separating the bearing cavity from a number of buffer air paths in communication with a plurality of buffer air entry points, and at least one scavenge passage inlet in the bearing cavity;an oil supply system including at least one oil path leading to the bearings;a first entry point of said plurality of buffer air entry points having a first flow rate specification value, said first entry point fluidly communicating with a first buffer air path and being in fluid flow communication with an associated secondary path leading to a portion of the gas path upstream of the bleed air aperture relative to flow along the gas path during normal flow conditions of the gas turbine engine, said first entry point communicating with the first buffer air path adapted to said first flow rate specification value, said first entry point being provided with a first plurality of flow restrictors disposed within the associated secondary path, including a first bearing seal of at least two bearing seals, said first plurality of flow restrictors collaborating with the first buffer air path in maintaining a first pressure to favour positive flow conditions across the first bearing seal of the at least two bearing seals, into the bearing cavity;a second entry point of said plurality of buffer air entry points having a second flow rate specification value, said second entry point fluidly communicating with a second buffer air path and being in fluid flow communication with a deviation path being partitioned from the portion of the gas path upstream of the bleed air aperture, said second entry point of said plurality of buffer air entry points communicating with the second buffer air path adapted to said second flow rate specification value, the second entry point being provided with a second plurality of flow restrictors disposed within the deviation path, including a second bearing seal of the at least two bearing seals, the second plurality of flow restrictors collaborating with the second buffer air path in maintaining a second pressure to favour positive flow conditions across the second bearing seal of the at least two bearing seals, into the bearing cavity, the second pressure being lower than the first pressure, the second plurality of flow restrictors being sized to maintain positive flow conditions across the second bearing seal of the at least two bearing seals toward the bearing cavity; anda buffer air supply including a plenum branching off to the first buffer air path and the second buffer air path, said first buffer air path flowing from the plenum in an upstream direction relative to the flow along the gas path during normal flow conditions of the gas turbine engine, and said second buffer air path flowing from the plenum in a downstream direction relative to the flow along the gas path. 12. The gas turbine engine of claim 11, comprising a flow restrictor formed in the second buffer air path, the flow restrictor throttling the flow rate of buffer air at the second entry point, thereby establishing the higher relative pressure at the first entry point. 13. The gas turbine engine of claim 11, wherein the second entry point is further in fluid flow communication both with an associated secondary path leading to the portion of the gas path upstream of the bleed air aperture relative to flow along the gas path, further comprising a baffle partitioning a subchamber of a low pressure entry point from the associated secondary path, said subchamber being adjacent the second one of the at least two bearing seals and in fluid flow communication with the deviation path, said baffle being operational upon flow reversal across the second one of the at least two bearing seals to guide fluid coming into the subchamber from the second one of the at least two bearing seals to the deviation path, and away from the secondary path. 14. The gas turbine engine of claim 11 wherein the first entry point is in fluid flow communication with the associated secondary path via a secondary seal. 15. The gas turbine engine of claim 11 wherein the gas turbine engine has two shafts, and the deviation path extends at least partially along an intershaft spacing provided between the two shafts. 16. The gas turbine engine of claim 11, wherein the buffer air supply has a connecting air path extending from the first entry point to the second entry point. 17. The gas turbine engine of claim 16 further comprising a flow restrictor formed in the connecting air path, the flow restrictor throttling the flow rate of buffer air to the second entry point, thereby establishing the higher relative pressure at the first entry point. 18. The gas turbine engine of claim 16, wherein the buffer air supply includes struts extending across the gas path being closed except for an inlet at an outer end and an outlet at an inner end, the struts being used as ducts for channeling buffer air across the gas path during which the buffer air can lose heat to the gas path. 19. The gas turbine engine of claim 18 wherein the outlets of two or more struts are interconnected by a plenum.