Gas turbine engine variable area fan nozzle control

Patent metadata

Field	Value
Publication number	US-10830178-B2
Application number	US-201816016636-A
Country	US
Kind code	B2
Filing date	Jun 24, 2018
Priority date	Jan 31, 2012
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

A method of managing a gas turbine engine includes the steps of detecting an airspeed and detecting a fan speed. A parameter relationship is referenced related to a desired variable area fan nozzle position based upon at least airspeed and fan speed. The detected airspeed and detected fan speed is compared to the parameter relationship to determine a target variable area fan nozzle position. An actual variable area fan nozzle position is adjusted in response to the determination of the target area fan nozzle position and at least one threshold.

First claim

What is claimed is:

1. A gas turbine engine comprising:
a fan section including a fan having a fan blade;
a compressor section including a low pressure compressor and a high pressure compressor;
a geared architecture;
a turbine section including a low pressure turbine and a high pressure turbine, the low pressure turbine driving the fan through the geared architecture;
a fan nacelle surrounding the fan and a core nacelle to provide a bypass flow path, and including a variable area fan nozzle movable between a first position and a second positions;
one or more actuators coupled to the variable area fan nozzle; and
a controller that references a parameter relationship relating to a desired variable area fan nozzle position based upon at least airspeed and fan speed, compares a detected airspeed and a detected fan speed to the parameter relationship to determine a target variable area fan nozzle position, the parameter relationship including first and second thresholds respectively corresponding to upper and lower fan speed limits that provide a schedule of curves of the fan speed in relation to a fan aerodynamic design speed, wherein the upper fan speed limit and the lower fan speed limits are less than the fan aerodynamic design speed, selects the target variable area fan nozzle position according to the schedule of curves, and provides a command to the one or more actuators to adjust the variable area fan nozzle from the first position to the second position corresponding to the target variable fan nozzle position.

2. The gas turbine engine according to claim 1 , wherein the variable area fan nozzle alters bypass flow in the bypass flow path in response to moving between the first position and second position.

3. The gas turbine engine according to claim 2 , further comprising a low fan pressure ratio of less than 1.45 across the fan blade alone.

4. The gas turbine engine according to claim 3 , wherein the variable area fan nozzle includes a plurality of flaps moveable between the first position and the second position in response to the one or more actuators.

5. The gas turbine engine according to claim 4 , wherein the plurality of flaps are linearly translatable relative to an engine longitudinal axis in response to the one or more actuators.

6. The gas turbine engine according to claim 5 , wherein the controller provides the target variable area fan nozzle position for a range of air speeds based upon the fan speed.

7. The gas turbine engine according to claim 6 , wherein the controller communicates with a low speed spool sensor, the low speed spool sensor detects a rotational speed of a low speed spool comprising the low pressure compressor and the low pressure turbine, and the controller determines the target variable area fan nozzle position based upon the rotational speed of the low speed spool.

8. The gas turbine engine according to claim 7 , wherein the controller detects the fan speed based upon the rotational speed of the low speed spool.

9. The gas turbine engine according to claim 7 , wherein the air speed range is 0.35-0.55 Mach.

10. The gas turbine engine according to claim 9 , wherein the lower fan speed limit corresponds to a value that is between 60% and 65% of the fan aerodynamic design speed, and the lower fan speed limit corresponds to a value that is between 70% and 75% of the fan aerodynamic design speed.

11. The gas turbine engine according to claim 10 , wherein the controller detects the fan speed based upon a gear reduction ratio of the geared architecture.

12. The gas turbine engine according to claim 11 , wherein the high pressure turbine includes two stages, and the low pressure turbine includes a greater number of stages than the high pressure turbine.

13. The gas turbine engine according to claim 12 , wherein the geared architecture is a planetary gear system.

14. The gas turbine engine according to claim 12 , wherein the controller communicates with a temperature sensor, the temperature sensor detects ambient temperature, and the controller corrects the fan speed based upon the ambient temperature.

15. The gas turbine engine according to claim 12 , wherein translation of the plurality of flaps relative to the engine longitudinal axis between the first position and the second position defines an annular vent to increase an exit area of the fan nacelle.

16. A method of managing a gas turbine engine comprising the steps of:
providing a fan including a fan blade arranged in a fan nacelle, the fan nacelle surrounding the fan and a core nacelle to provide a bypass flow path, and the fan nacelle including a variable area fan nozzle;
rotating a high speed spool about an engine longitudinal axis, the high speed spool including a high pressure compressor and a high pressure turbine;
rotating a low speed spool about the engine longitudinal axis, the low speed spool including a low pressure turbine;
driving the fan through a geared architecture at a lower speed than the low speed spool;
detecting an airspeed;
detecting a fan speed;
referencing a parameter relationship related to a desired variable area fan nozzle position based upon at least airspeed and fan speed, the parameter relationship including first and second thresholds respectively corresponding to upper and lower fan speed limits that provide a schedule of curves of the fan speed in relation to a fan aerodynamic design speed, wherein the upper fan speed limit and the lower fan speed limits are less than the fan aerodynamic design speed;
comparing the detected airspeed and the detected fan speed to the parameter relationship to determine a target variable area fan nozzle position according to the schedule of curves; and
adjusting an actual variable area fan nozzle position of the variable area fan nozzle to the target variable area fan nozzle position to adjust a bypass flow in the bypass flow path.

17. The method according to claim 16 , wherein the step of adjusting includes adjusting the target variable area fan nozzle position to adjust an exit area of the fan nacelle.

18. The method according to claim 17 , wherein the step of adjusting includes translating one or more flaps between a first position and a second position in response to one or more actuators.

19. The method according to claim 18 , wherein the step of comparing includes providing the target variable area fan nozzle position for a range of air speeds based upon the fan speed.

20. The method according to claim 19 , wherein the step of detecting the fan speed includes detecting a rotational speed of the low speed spool.

21. The method according to claim 20 , wherein the step of detecting the fan speed includes calculating the fan speed based upon a gear reduction ratio of the geared architecture.

22. The method according to claim 21 , wherein the air speed range is 0.35-0.55 Mach.

23. The method according to claim 22 , wherein the fan has a low fan pressure ratio of less than 1.45 across the fan blade alone.

24. The method according to claim 23 , wherein a low corrected fan tip speed of the fan is less than 1150 feet per second.

25. The method according to claim 24 , wherein the first position corresponds to a maximum of the exit area at air speeds below 0.35 Mach, and the second position corresponds to a minimum of the exit area at air speeds above 0.55 Mach.

26. The method according to claim 25 , wherein the lower fan speed limit corresponds

Assignees

• Raytheon Tech Corp

Inventors

• Blackwell Geoffrey T
• Mcvey William J
• Tempelman William G

Classifications

• F02C9/28

  Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed (F02C9/30 - F02C9/38, F02C9/44 take precedence) · CPC title

• F02C9/18

  by bleeding, bypassing or acting on variable working fluid interconnections between turbines or compressors or their stages {(F02C3/113 takes precedence)} · CPC title

• F05D2270/304

  Spool rotational speed · CPC title

• F02C9/16

  Control of working fluid flow (F02C9/48 takes precedence; control of air-intake flow F02C7/057) · CPC title

• F02C3/107

  with two or more rotors connected by power transmission · CPC title