GAS TURBINE ENGINE WITH AXIAL MOVABLE FAN VARIABLE AREA NOZZLE

• US 20090053058A1
• Filed: 08/23/2007
• Published: 02/26/2009
• Est. Priority Date: 08/23/2007
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Zamora, Sean P., Kohlenberg, Gregory A.
• Granted Patent: US 8,074,440 B2
• Time in Patent Office: Days
• US Class Current: 415/227
• CPC Class Codes: B64D 33/04 of exhaust outlets or jet pipes exhaust outlets for combustion engines in general F01N; jet pipes or nozzles for jet-propulsion plants per se F02K; plants characterised by the form or arrangement of the jet pipe or nozzle F02K ; attitude, flight direction, or altitude control by jet reaction B64C
• CPC Class Codes: F02K 1/30 for varying effective area of jet pipe or nozzle
• CPC Class Codes: F02K 1/72 the aft end of the fan housing being movable to uncover openings in the fan housing for the reversed flow

Abstract

A turbofan engine includes a fan variable area nozzle includes having a first fan nacelle section and a second fan nacelle section movably mounted relative the first fan nacelle section. The second fan nacelle section axially slides aftward relative to the fixed first fan nacelle section to change the effective area of the fan nozzle exit area.

Claims

1. A nacelle assembly for a for a high-bypass gas turbine engine comprising:

a core nacelle defined about an engine centerline axis;

a fan nacelle mounted at least partially around said core nacelle to define a fan bypass flow path; and

a fan variable area nozzle in communication with said fan bypass flow path, said fan variable area nozzle having a first fan nacelle section and a second fan nacelle section, said second fan nacelle section axially movable relative said first fan nacelle section to define an auxiliary port to vary a fan nozzle exit area and adjust fan bypass airflow, said auxiliary port no more than 0.1 del_x/L_duct forward of a point at which a fan bypass duct outer wall is parallel to said engine centerline axis.

2. The assembly as recited in claim 1, wherein said second fan nacelle section defines an auxiliary port entrance angle, said auxiliary port entrance angle relative to said first fan nacelle section less than 20 degrees.

3. The assembly as recited in claim 1, wherein an outer surface of said second fan nacelle section defines an R_arc/chord greater than 0.7.

4. The assembly as recited in claim 1, wherein said second fan nacelle section defines an auxiliary port entrance angle, said auxiliary port entrance angle relative to said first fan nacelle section less than 20 degrees, and an outer surface of said second fan nacelle section defines an R_arc/chord greater than 0.7.

5. The assembly as recited in claim 1, wherein said second fan nacelle section includes a first segment defined between a pylon and a lower bifi and a second segment defined between said pylon and said lower bifi.

6. The assembly as recited in claim 1, wherein said second fan nacelle section defines a trailing edge of said fan variable area nozzle.

7. The assembly as recited in claim 1, wherein said second fan nacelle section is subdivided into a multiple of independently operable sectors, each of said multiple of independently operable sectors axially movable relative said the first fan nacelle section to define an asymmetric fan nozzle exit area.

8. A nacelle system for a high-bypass gas turbine engine comprising:

a core engine defined about an axis;

a gear system driven by said core engine;

a turbofan driven by said gear system about said axis;

a core nacelle defined at least partially about said core engine;

a fan nacelle mounted at least partially around said core nacelle to define a fan bypass flow path; and

a fan variable area nozzle in communication with said fan bypass flow path, said fan variable area nozzle having a first fan nacelle section and a second fan nacelle section, said second fan nacelle section axially movable relative said first fan nacelle section to define an auxiliary port to vary a fan nozzle exit area and adjust fan bypass airflow, said auxiliary port no more than 0.1 del_x/L_duct forward of a point at which a fan bypass duct outer wall is parallel to said engine centerline axis.

9. The system as recited in claim 8, wherein said second fan nacelle section defines an auxiliary port entrance angle, said auxiliary port entrance angle relative to said first fan nacelle section less than 20 degrees.

10. The system as recited in claim 8, wherein an outer surface of said second fan nacelle section defines an R_arc/chord greater than 0.7.

11. The system as recited in claim 8, wherein said second fan nacelle section defines an auxiliary port entrance angle, said auxiliary port entrance angle relative to said first fan nacelle section less than 20 degrees, and an outer surface of said second fan nacelle section defines an R_arc/chord greater than 0.7.

12. The system as recited in claim 8, further comprising a controller in communication with an actuator system to axially move said second fan nacelle section relative to said first fan nacelle section to vary said fan nozzle exit area in response to a flight condition.

13. The system as recited in claim 12, wherein said second fan nacelle section is aligned with said first fan nacelle section about said axis to define a closed position of said fan nozzle exit area.

14. The system as recited in claim 13, wherein said second fan nacelle section is axially offset relative said first fan nacelle section along said track to define an open position of said fan nozzle exit area.

15. The system as recited in claim 8, wherein said second fan nacelle section axially movable generally along said track to vary a fan nozzle exit area to adjust fan bypass airflow such that an angle of attack of turbofan fan blades are maintained close to design incidence.

16. A method of varying a fan nozzle exit area of a gas turbine engine comprising the steps of:

(A) positioning a first fan nacelle section and a second fan nacelle section about an axis; and

(B) axially moving the second fan nacelle section between a closed position in which the second fan nacelle section is in sequential alignment with the first fan nacelle section in response to a cruise flight condition and an open positioning in which the second fan nacelle section is aftward of the first fan nacelle section to define a auxiliary port in response to a non-cruise flight condition.

17. A method as recited in claim 16, wherein said step (B) further comprises the step of:

(a) translating the second fan nacelle section aftward of the first fan nacelle section along a track adjacent a pylon and a lower bi-fi.

18. A method as recited in claim 16, wherein said step (B) further comprises the step of:

(a) defining the auxiliary port no more than 0.1 del_x/L_duct forward of a point at which a fan bypass duct outer wall is parallel to said engine centerline axis.

19. A method as recited in claim 16, wherein said step (B) further comprises the step of:

(a) defining an auxiliary port entrance angle, the auxiliary port entrance angle relative to said first fan nacelle section less than 20 degrees.

20. A method as recited in claim 16, wherein said step (B) further comprises the step of:

(a) defining an outer surface of the second fan nacelle section with an R_arc/chord greater than 0.7.