Adaptive fan system for a variable cycle turbofan engine

Patent metadata

Field	Value
Publication number	US-9624870-B2
Application number	US-201113637619-A
Country	US
Kind code	B2
Filing date	Mar 27, 2011
Priority date	Mar 26, 2010
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

An adaptive fan system for a variable cycle turbofan engine having at least one turbine, includes a shaft structured to receive mechanical power from a turbine in the variable cycle turbofan engine and a first fan stage that is coupled directly to the shaft and is driven directly by the shaft. A transmission system is coupled to the shaft and a second fan stage is coupled to the shaft via the transmission system and is driven by the shaft via the transmission system. The transmission system is structured to selectively vary a speed between high and low speeds at which power is supplied from the shaft to the second fan stage relative to at least one of the shaft and the first fan stage, wherein the first fan stage and the second fan stage are configured to rotate in the same direction and at the same high speed to increase the mechanical power of the turbine.

First claim

What is claimed is:

1. A gas turbine engine, comprising;
a compressor structured to compress an airflow received at the compressor and to output the compressed airflow as a compressor discharge airflow;
a combustor in fluid communication with said compressor, said combustor being structured to combust a mixture of a fuel and at least some of said compressor discharge airflow to generate a hot working airflow;
a turbine in fluid communication with said combustor, said turbine being configured to extract a mechanical power from said hot working airflow;
a shaft coupled to said turbine, said shaft being configured to receive and transmit said mechanical power from said turbine;
a first rotating load powered by said shaft;
a second rotating load powered by said shaft, wherein the first rotating load and the second rotating load rotate in the same direction; and
a transmission system including:
a geartrain coupled to said shaft;
a clutching mechanism coupled to said shaft in parallel to said geartrain,

wherein said clutching mechanism includes a clutch and a positive locking mechanism disposed axially aft in relation to the clutch, wherein the second rotating load is disposed forward of the clutch, wherein the clutch couples the shaft to the second rotating load through alternating engagement of one of the positive locking mechanism and the geartrain such that when the positive locking mechanism is engaged the second rotating load is driven by the shaft at a same speed as the first rotating load and when the geartrain is engaged the second rotating load is driven at a speed less than the speed of the first rotating load, said transmission system being structured to selectively vary a speed at which power is supplied from said shaft to said second rotating load relative to a speed of at least one of said shaft and said first rotating load, wherein to increase extraction of mechanical power the second rotating load rotates at a same speed as the first rotating load.

2. The gas turbine engine of claim 1 , configured as a turbofan engine, wherein said first rotating load is a fan stage.

3. The gas turbine engine of claim 2 , configured as a variable cycle turbofan engine, wherein said second rotating load is an other fan stage.

4. The gas turbine engine of claim 3 , further comprising:
a first bypass duct configured to bypass at least a portion of the output of said fan stage to provide a thrust component; and
a second bypass duct configured to bypass at least a portion of the output of said other fan stage to provide an other thrust component,
wherein said turbine is configured to output a third thrust component.

5. The gas turbine engine of claim 1 , wherein said first rotating load is coupled directly to said shaft, and wherein said second rotating load is coupled to said shaft via said transmission system.

6. The gas turbine engine of claim 5 , wherein the transmission system coupled to said shaft is configured to drive said second rotating load at a speed different from the speed of said shaft.

7. The gas turbine engine of claim 1 , wherein said clutch is a friction clutch.

8. The gas turbine engine of claim 1 , said transmission system further including an overrunning clutch coupled between said second rotating load and said shaft, wherein said transmission system is structured to transmit power to drive said second rotating load upon the speed of said second rotating load decaying to a predetermined speed relative to the speed of said shaft.

9. A gas turbine engine system, comprising:
a compressor structured to compress an airflow received at the compressor and to output the compressed airflow as a compressor discharge airflow;
a combustor in fluid communication with said compressor, said combustor being structured to combust a mixture of a fuel and at least some of said compressor discharge airflow to generate a hot working airflow;
a turbine in fluid communication with said combustor, said turbine being configured to extract a mechanical power from said hot working airflow;
a base rotating load;
a variable-speed rotating load; and
a transmission system configured to transmit power from said turbine to at least one of said base rotating load and said variable-speed rotating load via a shaft, the transmission system including:
a geartrain coupled to said shaft;
a clutching mechanism coupled to said shaft in parallel to said geartrain,

wherein said clutching mechanism includes a clutch and a positive locking mechanism disposed axially aft in relation to the clutch, wherein the variable-speed rotating load is disposed forward of the clutch, wherein the clutch couples the shaft to the variable-speed rotating load through alternating engagement of one of the positive locking mechanism and the geartrain such that when the positive locking mechanism is engaged the variable-speed rotating load is driven by the shaft at a same speed as the base rotating load and when the geartrain is engaged the variable-speed rotating load is driven at a speed less than the speed of the base rotating load,
wherein the transmission system is structured to selectively vary a speed at which power is supplied from said turbine to said variable-speed rotating load relative to a speed of said base rotating load, wherein to increase extraction of mechanical power the variable-speed rotating load rotates at a same speed and in a same direction as the base rotating load.

10. The gas turbine engine system of claim 9 , wherein said base rotating load is a fan stage.

11. The gas turbine engine system of claim 10 , wherein said variable-speed rotating load is an other fan stage.

12. The gas turbine engine system of claim 10 , wherein said base rotating load is a variable-speed load.

13. The gas turbine engine system of claim 9 , wherein said shaft is operative to rotate said base rotating load at the same speed as said turbine.

14. The gas turbine engine system of claim 13 , wherein said transmission system is operative to selectively rotate said variable-speed rotating load at the same speed as said turbine or to rotate said variable-speed rotating load at a different speed than said turbine.

15. The gas turbine engine system of claim 13 , wherein said clutch is a friction clutch, and wherein said friction clutch is operative to selectively couple said variable-speed rotating load directly to said shaft or to couple said variable-speed rotating load to said shaft via said geartrain.

16. An adaptive fan system for a variable cycle turbofan engine having at least one turbine, comprising:
a shaft structured to receive mechanical power from a turbine in said variable cycle turbofan engine;
a fan stage coupled directly to said shaft and driven directly by said shaft;
a transmission system coupled to said shaft;
an other fan stage coupled to said shaft via said transmission system and driven by said shaft via said transmission system, the transmission system including:
a geartrain coupled to said shaft;
a clutching mechanism coupled to said shaft in parallel to said geartrain,

wherein said clutching mechanism includes a clutch and a positive locking mechanism disposed axially aft in relation to the clutch, wherein the other fan stage is disposed forward of the clutch, wherein the clutch couples the shaft to the other fan stage through alternating engagement of one of the positive locking mechanism and the geartrain such that when the positive locking mechanism is engaged the other fan stage is driven by the shaft at a same speed as the fan stage and when the geartrain is engaged the other fan stage is drive

Assignees

• Ress Jr Robert A
• Stratton Steve
• Starr Matthew J
• Rolls Royce Nam Tech Inc

Inventors

• Ress Jr Robert A
• Stratton Steve
• Starr Matthew J

Classifications

• F02K3/077

  the plant being of the multiple flow type, i.e. having three or more flows · CPC title

• F02C3/113 Primary

  with variable power transmission between rotors · CPC title

• F02C7/32

  Arrangement, mounting, or driving, of auxiliaries · CPC title

• F02K3/075 Primary

  controlling flow ratio between flows · CPC title

• F02C7/36

  Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H) · CPC title