AFT cascade translating variable area fan nozzle

Patent metadata

Field	Value
Publication number	US-9617871-B2
Application number	US-201313949986-A
Country	US
Kind code	B2
Filing date	Jul 24, 2013
Priority date	Jul 24, 2012
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

An aircraft turbofan engine variable area fan nozzle (VAFN) is disclosed that has a forward end that is continuously supported within a circumferential recess in the wall of the nacelle in front of it. During operation, the VAFN translates back and forth but always has its front end within the recess. Relatively simple seals help seal the recess against the VAFN. An array of openings with aft facing vanes, termed an aft cascade, is built into the VAFN. The openings are hidden within the recess when the VAFN is in the forward-most positions, and they are exposed to allow air to flow from the bypass duct through the cascade when the VAFN is in aft positions. The aft cascades can have different airflow directions based on their locations around the engine.

First claim

What is claimed is:

1. A nacelle assembly apparatus for a turbofan engine, the apparatus comprising:
a nacelle wall defining a bypass duct that extends at least partially around a centerline of a turbofan engine, the bypass duct being configured to transport bypass airflow of the engine, the nacelle wall having an aft end recess within a thickness of the nacelle wall; and
an arcuate variable area fan nozzle (VAFN) section having a front region, a center region, and a trailing edge, the VAFN section being movable between (a) a fully forward position and (b) a fully aft position, the front region of the VAFN section configured to be at least partially supported within the recess of the nacelle wall at all positions between and including the fully forward and fully aft positions, and the center region configured within the recess of the nacelle wall where the VAFN section is in the fully forward position;
wherein the VAFN section is configured to bear against and be at least partially supported by an internal lip of the recess, and the VAFN section is radially outboard of the internal lip.

2. The apparatus of claim 1 , wherein the VAFN section is configured to bear against and be at least partially supported by a second internal lip of the recess, and the VAFN section is radially inboard of the second internal lip.

3. The apparatus of claim 1 , wherein the internal lip of the recess comprises a seal.

4. The apparatus of claim 1 , further comprising:
an aperture through the center region of the VAFN section, the aperture covered by the nacelle wall recess when the VAFN section is in the fully forward position, the aperture exposed when then VAFN section is in the fully aft position,
whereby when the VAFN section is in the fully aft position and the aperture is exposed, bypass airflow can exit the aperture.

5. The apparatus of claim 4 , further comprising:
at least one vane disposed within the aperture and dividing the aperture into rows of openings, the at least one vane configured to direct bypass airflow in an aft direction.

6. The apparatus of claim 5 , wherein at least one of the rows of openings has an axial length different from an axial length of another of the rows of openings.

7. The apparatus of claim 4 , further comprising a plurality of vanes disposed within the aperture, such that the plurality of vanes extend around at least a partial circumference of the engine.

8. The apparatus of claim 7 , wherein a vane at a first circumferential position of the engine is configured to direct bypass airflow farther forward or aft than a vane at a second, different circumferential position of the engine.

9. The apparatus of claim 1 , wherein when the VAFN section is in the fully forward position, the VAFN section forms a substantially continuous outer surface extending from an outer surface of the nacelle wall to an outer surface of the VAFN section.

10. The apparatus of claim 9 , wherein when the VAFN section is in the fully forward position, the VAFN section forms a substantially continuous bypass duct-facing surface extending from a bypass duct-facing surface of the nacelle wall to a bypass duct-facing surface of the VAFN section.

11. The apparatus of claim 1 , further comprising:
an inner fixed structure, the VAFN section configured to move with respect to the inner fixed structure to vary an exit area of the bypass duct.

12. A nacelle assembly apparatus for a turbofan engine, the apparatus comprising:
a nacelle wall defining a bypass duct that extends at least partially around a centerline of a turbofan engine, the bypass duct being configured to transport bypass airflow of the engine, the nacelle wall having an aft end recess within a thickness of the nacelle wall;
an arcuate variable area fan nozzle (VAFN) section having a front region, a center region, and a trailing edge, the VAFN section being movable between (a) a fully forward position and (b) a fully aft position, the front region of the VAFN section configured to stay within the recess of the nacelle wall at all positions between and including the fully forward and fully aft positions, the center region having a cascade of vanes defining multiple rows of openings, the vanes configured to direct bypass airflow in an aft direction; and
an actuator configured to move the VAFN section between predetermined settings between the fully forward and fully aft positions;
the aft end recess defined by an inner structure of the nacelle wall; and
at least a front portion of the VAFN section configured to radially engage at least a portion of the inner structure, which axially and circumferentially overlaps the front portion of the VAFN section, during VAFN section movement.

13. The apparatus of claim 12 , wherein the predetermined settings are associated with take-off, cruise, and landing.

14. The apparatus of claim 12 , wherein at least one of the rows of openings has an axial length different from an axial length of another of the rows of openings.

15. The apparatus of claim 12 , wherein the predetermined settings are configured to halt movement of the VAFN section after each row of openings is exposed or covered.

16. A method of adjusting a fan bypass exit area of a turbofan engine with a variable area fan nozzle (VAFN), the method comprising:
translating an arcuate VAFN section with respect to an inner fixed structure of a turbofan engine, the VAFN section having a front region, a center region, and a trailing edge, the translating causing a radial distance between the trailing edge and the inner fixed structure to change, thereby changing a fan bypass exit area of the engine;
translating aft the VAFN section to expose a first row of openings through the center region, thereby allowing bypass airflow to exit through the openings as well as exit between the trailing edge and the inner fixed structure; and
translating forward the VAFN section to cover the first row of openings such that the first and second rows of openings are covered,
wherein the front region of the VAFN section is at least partially supported within a recess of a nacelle wall during each of the translatings to expose and cover the first row of openings;
wherein the recess is defined by an inner structure of the nacelle wall; and
wherein at least a front portion of the VAFN section radially engages at least a portion of the inner structure, which axially and circumferentially overlaps the front portion of the VAFN section, during the translatings of the VAFN section.

17. The method of claim 16 , further comprising:
translating further aft the VAFN section to expose a second row of openings through the center region such that the first and second rows of openings are exposed, the front region at least partially supported within the recess of the nacelle wall; and
translating forward the VAFN section to cover the second row of openings,
wherein the front region of the VAFN section is at least partially supported within the recess of a nacelle wall during the translating movements to expose and cover the second row of openings.

18. The method of claim 17 , further comprising:
automatically stopping the translating between exposing the first row and exposing the second row.

19. The method of claim 17 , further comprising:
automatically stopping the translating between covering the first row and covering the second row.

20. The method of claim 16 , wherein the translating movements are performed during flight of the engine.

Assignees

• Rohr Inc

Inventors

• Gormley Timothy

Classifications

• B64D29/00

  Power-plant nacelles, fairings or cowlings · CPC title

• F01D25/24 Primary

  Casings (modified for heating or cooling F01D25/14); Casing parts, e.g. diaphragms, casing fastenings (casings for rotary machines or engines in general F16M {; special arrangements in stators dealing with breaking-off of part of rotor F01D21/045}) · CPC title

• F01D9/02

  Nozzles; Nozzle boxes; Stator blades; Guide conduits {, e.g. individual nozzles (nozzle boxes F01D9/047)} · CPC title

• F02K1/42

  the means being movable into an inoperative position · CPC title

• B64D33/04

  of exhaust outlets or jet pipes · CPC title