Gas turbine engine with variable geometry fan exit guide vane system
A turbofan engine includes a variable geometry fan exit guide vane (FEGV) system having a multiple of circumferentially spaced radially extending fan exit guide vanes. Rotation of the fan exit guide vanes between a nominal position and a rotated position selectively changes a fan bypass flow path to permit efficient operation at various flight conditions.
1. A fan section of a gas turbine engine comprising:
a multiple of fan exit guide vanes, arranged about a central longitudinal axis, defining a throat area leading to a fan nozzle exit area, at least one of said multiple of fan exit guide vanes movable to change the throat area, wherein each of said multiple of fan exit guide vanes include a pivotable portion and a fixed portion, said pivotable portion rotatable about an axis of rotation relative to said fixed portion, said axis of rotation transverse to the central longitudinal axis or at an angle to the central longitudinal axis.
2. The fan section as recited in claim 1 , wherein said at least one of said multiple of fan exit guide vanes are rotatable to change said fan nozzle exit area.
3. The fan section as recited in claim 1 , wherein said multiple of fan exit guide vanes are mounted within an intermediate engine case structure.
4. The fan section as recited in claim 3 , wherein a unison ring operates to rotate each of the multiple of fan exit guide vanes.
5. The fan section as recited in claim 4 , wherein the unison ring is located in the intermediate case structure.
6. The fan section as recited in claim 1 , wherein said pivotable portion includes a leading edge flap.
7. The fan section as recited in claim 1 , wherein each of said multiple of fan exit guide vanes are movable to change said throat area leading to said fan nozzle exit area.
8. The fan section as recited in claim 1 , wherein each of said multiple of fan exit guide vanes are rotatable to change said fan nozzle exit area.
9. The fan section as recited in claim 1 , wherein each said pivotable portion slides relative to the fixed portion, forming a slot between the pivotable portion and the fixed portion.
10. The fan section as recited in claim 9 , wherein the axis of rotation is located about the geometric center of gravity of each of the fan exit guide vane cross section.
11. The fan section as recited in claim 1 , wherein the multiple of fan exit guide vanes communicates with a controller to move the fan exit guide vanes and change the fan nozzle exit area by changing the throat area.
12. A gas turbine engine comprising:
a core section defined about an engine axis;
a fan section mounted at least partially around said core section to define a fan bypass flow path; and
a multiple of fan exit guide vanes in communication with said fan bypass flow path to define a throat area leading to a fan nozzle exit area, at least one of said multiple of fan exit guide vanes movable to change the throat area, wherein said at least one of said multiple of fan exit guide vanes includes a pivotable portion and a fixed portion, said pivotable portion rotatable about an axis of rotation relative to said fixed portion, said axis of rotation transverse to the engine axis or at an angle to the engine axis.
13. The engine as recited in claim 12 , wherein said at least one of said multiple of fan exit guide vanes is rotatable about an axis transverse to said engine axis.
14. The engine as recited in claim 12 , wherein all of said multiple of fan exit guide vanes are rotatable.
15. The engine as recited in claim 12 , wherein said multiple of fan exit guide vanes are mounted within an intermediate engine case structure.
16. The engine as recited in claim 12 , wherein said pivotable portion includes a leading edge flap.
17. The engine as recited in claim 12 , wherein said core section includes a core nacelle supported by a core case structure.
18. The engine as recited in claim 12 , wherein said fan section includes a fin nacelle supported by a fan case structure.
19. The engine as recited in claim 12 , wherein the multiple of fan exit guide vanes communicates with a controller, said multiple of fan exit guide vanes selectively adjusted to adjst a pressure ratio of the bypass flow path in response to the controller.
20. The engine as recited in claim 12 , wherein said at least one of said multiple of fan exit guide vanes is rotatable about an axis at an angle to said engine axis.
21. A method of changing a fan nozzle exit area of a gas turbine engine comprising the steps of:
(A) selectively moving at least one of a multiple of fan exit guide vanes to change a throat area leading to a fan nozzle exit area in response to a flight condition, wherein at least one of said multiple of fan exit guide vanes includes a pivotable portion and a fixed portion, said pivotable portion movable about an axis of rotation relative to said fixed portion, said axis of rotation transverse to an engine axis or at an angle to the engine axis.
22. The method as recited in claim 21 , wherein said step (A) further comprises:
(a) at least partially moving at least one of the multiple of fan exit guide vanes to increase the fan nozzle exit area in response to a non-cruise flight condition.
23. The method as recited in claim 21 , wherein said step (A) further comprises:
(a) at least partially moving at least one of the multiple of fan exit guide vanes to at least partially block the bypass flow path with the at least one of the multiple of fan exit guide vanes to provide an asymmetrical fan nozzle exit area.
24. The method as recited in claim 23 , wherein said step (A) further comprises:
(a) at least partially blocking the bypass flow path with the at least one of the multiple of fan exit guide vanes to at least partially spoil the bypass flow through the bypass flow path.
25. A fan section of a gas turbine engine comprising:
a multiple of fan exit guide vanes, arranged about a central longitudinal axis, defining a throat area leading to a fan nozzle exit area, at least one of said multiple of fan exit guide vanes movable to change the throat area, wherein each of said multiple of fan exit guide vanes includes a pivotable portion and a fixed portion, said pivotable portion movable about an axis of rotation relative to said fixed portion, said axis of rotation transverse to the central longitudinal axis or at angle to the central longitudinal axis.
26. The fan section as recited in claim 25 , wherein each of said multiple of fan exit guide vanes define a slotted vane arrangement.