# US 10,308,368 B2 · Turbofan engine and method of reducing air flow separation therein > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,308,368 B2 - Document ID: US10308368B2 - Status: Granted - Kind: B2 - Application number: 14/928,164 - Filed: 2015-10-30 - Published: 2017-05-04 - Granted: 2019-06-04 - Earliest claimed: 2015-10-30 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Nikolai N. Pastouchenko - Web page: https://patentgrep.com/patent/US10308368B2 ## CPC - B64D 33/02: of combustion air intakes - B64D 27/16: of jet type - B64D 29/00: Power-plant nacelles, fairings or cowlings - F04D 29/522: {especially adapted for elastic fluid pumps} - F04D 29/682: {by fluid extraction} - F04D 29/684: {by fluid injection} - B64D 2033/0206: {comprising noise reduction means, e.g. acoustic liners} - B64D 2033/0226: {comprising boundary layer control means} - F05D 2220/36: specially adapted for the fan of turbofan engines - F05D 2270/102: caused by working fluid flow velocity profile distortion - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A turbofan engine is provided. The turbofan engine includes a nacelle housing including a radially outer wall and a radially inner wall that defines an interior cavity within the nacelle housing. The turbofan engine also includes a fan assembly positioned at least partially within the interior cavity. A flow passage is defined between the radially outer wall and the radially inner wall for channeling a flow of air therethrough. The flow passage is configured to couple a portion of the interior cavity upstream from the fan assembly in flow communication with an ambient environment exterior from the radially outer wall. ## Claims ### Claim 1 A turbofan engine comprising: a nacelle housing comprising a radially outer wall and a radially inner wall that defines an interior cavity within said nacelle housing, wherein said nacelle housing further comprises: a plurality of first openings defined in said radially inner wall for channeling a flow of air therethrough and an opening defined in the radially outer wall; an acoustic liner positioned between said radially outer wall and said radially inner wall, wherein the acoustic liner comprises: a honeycomb structure coupled to said radially inner wall, wherein the honeycomb structure comprises one or more channels defined therein that at least partially define a flow passage; and a face sheet coupled to the honeycomb structure on an opposing side thereof from said radially inner wall, wherein the face sheet comprises a plurality of second openings defined therein; a fan assembly positioned at least partially within said interior cavity, wherein said flow passage is defined between said radially outer wall and said radially inner wall for channeling the flow of air therethrough, said flow passage configured to couple a portion of said interior cavity upstream from said fan assembly in flow communication with an ambient environment exterior from said radially outer wall, wherein the opening in the radially outer wall, the plurality of second openings, the respective one or more channels, and the respective first openings are coupled in a serial flow relationship to enable the flow of air; and said nacelle housing further comprising an actuating door coupled to said radially outer wall of said nacelle housing, said actuating door selectively positioned between an open position and a closed position. ### Claim 2 (depends on 1) The turbofan engine in accordance with claim 1, wherein said radially outer wall is defined on a high pressure side of said nacelle housing, and said radially inner wall is defined on a low pressure side of said nacelle housing such that the flow of air naturally flows from exterior of said nacelle housing towards said interior cavity through said flow passage. ### Claim 3 (depends on 2) The turbofan engine in accordance with claim 2, wherein said plurality of first openings positioned upstream from said fan assembly. ### Claim 4 (depends on 3) The turbofan engine in accordance with claim 3, wherein said plurality of first openings are angled obliquely relative to a surface of said radially inner wall such that, the flow of air that naturally flows from exterior of said nacelle housing is directed towards said fan assembly. ### Claim 5 (depends on 1) The turbofan engine in accordance with claim 1, wherein said actuating door is in the open position when a velocity of a crosswind at said radially outer wall is greater than a predetermined threshold, and is in the closed position when the crosswind velocity is less than the predetermined threshold. ### Claim 6 An aircraft comprising: a fuselage; a wing structure coupled to said fuselage; and a turbofan engine coupled to at least one of said fuselage and said wing structure, said turbofan engine comprising: a nacelle housing comprising a radially outer wall and a radially inner wall that defines an interior cavity within said nacelle housing, wherein said nacelle housing further comprises: a plurality of first openings defined in said radially inner wall for channeling flow of air therethrough and an opening defined in the radially outer wall; an acoustic liner positioned between said radially outer wall and said radially inner wall, wherein the acoustic liner comprises: a honeycomb structure coupled to said, radially inner wall, wherein the honeycomb structure comprises one or more channels defined therein that at least partially define a flow passage; and a face sheet coupled to the honeycomb structure on an opposing side thereof from said radially inner wall, wherein the face sheet comprises a plurality of second openings defined therein; a fan assembly positioned at least partially within said interior cavity, wherein said flow passage is defined between said radially outer wall and said radially inner wall for channeling the flow of air therethrough, said flow passage configured to couple a portion of said interior cavity upstream from said fan assembly in flow communication with an ambient environment exterior from said radially outer wall, wherein the opening in the radially outer wall, the plurality of second openings, the respective one or more channels, and the respective first openings are coupled in a serial flow relationship to enable the flow of air; and said nacelle housing further comprises an actuating door coupled to said radially outer wall of said nacelle housing, said actuating door selectively positioned between an open position and a closed position. ### Claim 7 (depends on 6) The aircraft in accordance with claim 6, wherein said radially outer wall is defined on a high pressure side of said nacelle housing, and said radially inner wall is defined on a low pressure side of said nacelle housing such that the flow of air naturally flows from exterior of said nacelle housing towards said interior cavity via said flow passage. ### Claim 8 (depends on 7) The aircraft in accordance with claim 7, wherein said plurality of first openings positioned upstream from said fan assembly. ### Claim 9 (depends on 8) The aircraft in accordance with claim 8, wherein said plurality of first openings are angled obliquely relative to a surface of said radially inner wall such that the flow of air that naturally flows from exterior of said nacelle housing is directed towards said fan assembly. ### Claim 10 (depends on 6) The aircraft in accordance with claim 6, wherein said actuating door is in the open position when the aircraft is traveling at a first velocity, and is in the closed position when the aircraft is traveling at a greater second velocity. ### Claim 11 A method of reducing air flow separation in a turbofan engine, said method comprising: defining a flow passage between a radially outer wall and a radially inner wall of a nacelle housing of the turbofan engine, wherein the flow passage is configured to couple a portion of an interior cavity of the nacelle housing upstream from a fan assembly in flow communication with an ambient environment exterior from the radially outer wall, wherein said nacelle housing comprises a plurality of first openings defined in said radially inner wall and an opening defined in the radially outer wall, an acoustic liner positioned between said radially outer wall and said radially inner wall, wherein the acoustic liner comprises a honeycomb structure coupled to said radially inner wall, wherein the honeycomb structure comprises one or more channels and a face sheet coupled to the honeycomb structure on an opposing side thereof from said radially inner wall, wherein the face sheet comprises a plurality of second openings defined therein; channeling a flow of air between the interior cavity and the ambient environment, wherein the opening in the radially outer wall, the plurality of second openings, the respective one or more channels, and the respective first openings are coupled in a serial flow relationship to enable the flow of air; and selectively positioning an actuating door defined in the radially outer wall between an open position and a closed position, such that the flow of air is selectively channeled through the flow passage. ### Claim 12 (depends on 11) The method in accordance with claim 11 further comprising: defining the radially outer wall on a high pressure side of the nacelle housing; and defining the radially inner wall on a low pressure side of the nacelle housing such that the flow of air naturally flows from exterior of the nacelle housing, towards the interior cavity via the flow passage. ### Claim 13 (depends on 11) The method in accordance with claim 11 further comprising drawing the flow of air from the interior cavity towards the ambient environment exterior from the radially outer wall. ### Claim 14 (depends on 1) The turbofan engine in accordance with claim 1, wherein plurality of first openings are angled obliquely relative to an inner surface of the radially inner wall such that the air drawn from the interior cavity flows through the plurality of first openings in a downstream direction. ### Claim 15 (depends on 1) The turbofan engine in accordance with claim 1, wherein the plurality of first openings are angled such that an inlet of each of the plurality of first openings is positioned radially outward from an outlet of each of the plurality of first openings. ### Claim 16 (depends on 1) The turbofan engine in accordance with claim 1, further comprising a high-pressure turbine and a low-pressure turbine arranged in a serial and axial flow relationship. ### Claim 17 (depends on 5) The turbofan engine in accordance with claim 5, wherein the turbofan engine comprises a centerline, and wherein crosswind is misaligned with the centerline such that a flow of intake air channeled towards the fan assembly is distorted. ### Claim 18 (depends on 11) The method in accordance with claim 11, further comprising drawing the flow of air from the interior cavity to facilitate re-attaching a flow of intake air to an inner surface of the radially inner wall.