# US 11,078,843 B2 · Thermal management of a gas turbine engine shaft > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,078,843 B2 - Document ID: US11078843B2 - Status: Granted - Kind: B2 - Application number: 15/993,675 - Filed: 2018-05-31 - Published: 2019-12-05 - Granted: 2021-08-03 - Earliest claimed: 2018-05-31 - Assignees: Raytheon Technologies Corporation - Applicants: United Technologies Corporation - Inventors: Gary D. Roberge; Jorn Axel Glahn - Web page: https://patentgrep.com/patent/US11078843B2 ## CPC - F02C 6/06: providing compressed gas (F02C6/10 takes precedence) - F02C 7/18: the medium being gaseous, e.g. air {(F02C7/125 takes precedence)} - F01D 5/085: {cooling fluid circulating inside the rotor} - F01D 25/125: {of bearings} - F02C 7/32: Arrangement, mounting, or driving, of auxiliaries - F02K 3/06: with front fan - F05D 2240/50: Bearings - F05D 2240/55: Seals - F05D 2240/61: Hollow - F05D 2260/20: Heat transfer, e.g. cooling - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A gas turbine engine includes a fan rotor, a compressor section, a combustor section, and a turbine section. The turbine section is positioned downstream of the combustor section. A fan drive turbine in the turbine section, and a shaft connects the fan drive turbine to the fan rotor. An inlet duct is connected to a cooling air source and connected to a cooling compressor downstream of the fan drive turbine. The cooling compressor is connected to an air source, and connected to a turning duct for passing compressed air in an upstream direction through the shaft. A method is also disclosed. ## Claims ### Claim 1 A gas turbine engine comprising: a fan rotor, a compressor section, a combustor section, and a turbine section, said turbine section being positioned downstream of said combustor section; a fan drive turbine in said turbine section, and a shaft connecting said fan drive turbine to said fan rotor, said shaft also driving a cooling compressor; an inlet duct connected to a cooling air source and connected to provide air to said cooling compressor downstream of said fan drive turbine, and said cooling compressor is connected to a turning duct for passing compressed air from said cooling compressor in an upstream direction through said shaft; and wherein there being connection passages in said shaft to provide communication between inner and outer passages in said shaft such that the compressed air, having passed in said upstream direction through said shaft in one of said inner and outer passages is returned in the other of said inner and outer passages in a downstream direction to provide cooling to said shaft. ### Claim 2 (depends on 1) The gas turbine engine as set forth in claim 1, wherein said turning duct extending to initially pass the compressed air downstream of said cooling compressor in said downstream direction, and then turn the compressed air into the upstream direction. ### Claim 3 (depends on 2) The gas turbine engine as set forth in claim 2, wherein a tube is positioned within said shaft to define said inner and outer passages, and said connection passages extend through said tube to communicate between said inner and outer passages. ### Claim 4 (depends on 3) The gas turbine engine as set forth in claim 3, wherein a plurality of bearings support said shaft. ### Claim 5 (depends on 4) The gas turbine engine as set forth in claim 4, wherein bearing outlet passages extend through said shaft, said bearing outlet passages positioned to provide cooling air to said bearings. ### Claim 6 (depends on 1) The gas turbine engine as set forth in claim 1, wherein said inlet duct communicates with a bypass duct that is positioned outwardly of a core engine including said compressor section, said combustor section, and said turbine section, and said bypass duct providing said cooling air source. ### Claim 7 (depends on 1) The gas turbine engine as set forth in claim 1, wherein said cooling compressor is connected to said shaft by a flexible shaft portion having undulations. ### Claim 8 (depends on 1) The gas turbine engine as set forth in claim 1, wherein a gear reduction is positioned between said fan drive turbine and said fan rotor. ### Claim 9 (depends on 8) The gas turbine engine as set forth in claim 8, wherein a plurality of bearings support said shaft. ### Claim 10 (depends on 9) The gas turbine engine as set forth in claim 9, wherein bearing outlet passages extend through said shaft, said bearing outlet passages positioned to provide cooling air to said bearings. ### Claim 11 (depends on 1) The gas turbine engine as set forth in claim 1, wherein a plurality of bearings support said shaft. ### Claim 12 (depends on 11) The gas turbine engine as set forth in claim 11, wherein bearing outlet passages extend through said shaft, said bearing outlet passages positioned to provide cooling air to said bearings. ### Claim 13 A method of operating a gas turbine engine comprising the steps of: driving a fan drive turbine in a turbine section, and driving a shaft connecting said fan drive turbine to drive a fan rotor, an outer passage within said shaft, and an inner passage within said shaft; supplying cooling air into an inlet duct and then to a cooling compressor driven by said shaft downstream of said fan drive turbine, and passing compressed air from the cooling compressor in an upstream direction through one of said inner and outer passages in said shaft, and providing communication between said inner and outer passages such that the compressed air, having passed in said upstream direction is returned in the other of said inner and outer passages in a downstream direction to provide cooling to said shaft; and said one of said inner and outer passages being said outer passage, with the other of said inner and outer passages being said inner passage. ### Claim 14 (depends on 13) The method as set forth in claim 13, including the step of initially passing the compressed air downstream of said cooling compressor in a downstream direction, and then turning the compressed air into the upstream direction. ### Claim 15 A gas turbine engine comprising: a fan rotor, a compressor section, a combustor section, and a turbine section, said turbine section being positioned downstream of said combustor section; a fan drive turbine in said turbine section, and a shaft connecting said fan drive turbine to said fan rotor, said shaft also driving a cooling compressor; an inlet duct connected to a cooling air source and connected to provide air to said cooling compressor downstream of said fan drive turbine, and said cooling compressor is connected to a turning duct for passing compressed air from said cooling compressor in an upstream direction through said shaft; connection passages in said shaft to provide communication between inner and outer passages in said shaft such that the compressed air, having passed in said upstream direction through said shaft in one of said inner and outer passages is returned in the other of said inner and outer passages in a downstream direction to provide cooling to said shaft; said turning duct extending to initially pass the compressed air downstream of said cooling compressor in said downstream direction, and then turn the compressed air into the upstream direction; and wherein a tube is positioned within said shaft to define said inner and outer passages, and said connection passages extend through said tube to communicate between said inner and outer passages, with compressed air downstream of said turning duct intially passing through said outer passage in said upstream direction, and then turning into said inner passage to return in said downstream direction. ### Claim 16 (depends on 15) The gas turbine engine as set forth in claim 15, said turning duct has a downstream end with an end flange capturing an end of said shaft, with a seal sitting between said end flange and said shaft. ### Claim 17 (depends on 1) The gas turbine engine as set forth in claim 1, wherein said turning duct has a downstream end with an end flange capturing an end of said shaft, with a seal sitting between said end flange and said shaft.