Gas turbine engine with selective flow path

Abstract

A gas turbine engine includes a gas generator with at least one compressor rotor, at least one gas generator turbine rotor and a combustion section. There is a duct located downstream of the gas generator. The duct is configured to move between a first position and a second position. A fan drive turbine is positioned downstream of a path of the products of combustion and passes over at least one gas generator turbine rotor when the duct is in the first position. The fan drive turbine is for driving a shaft and the shaft is for engaging gears to drive at least two fan rotors. An augmentor section is positioned downstream of a path of products of combustion and passes over at least one gas generator turbine rotor when the duct is in second position.

Claims

1. A gas turbine engine comprising: a gas generator with at least one compressor rotor, at least one gas generator turbine rotor and a combustion section; a duct located downstream of said gas generator, said duct including an annular outlet configured to move between a first position and a second position; wherein in the first position, the annular outlet connects the gas generator to an inlet of a fan drive turbine positioned downstream of a path of products of combustion having passed over a surface of said at least one gas generator turbine rotor and said duct, said fan drive turbine for driving a shaft and said shaft for engaging gears to drive at least two fan rotors, wherein an axis of rotation of said fan drive turbine is transverse to a gas generator axis of rotation; and wherein in the second position, the annular outlet connects the gas generator to an inlet of an augmentor section positioned downstream of said path of products of combustion having passed over said at least one gas generator turbine rotor and said duct.

2. The gas turbine engine as set forth in claim 1, wherein said duct is a three bearing swivel duct.

3. The gas turbine engine as set forth in claim 1, wherein said augmentor section includes at least one spray bar for injecting fuel into an exhaust stream.

4. The gas turbine engine as set forth in claim 3, wherein said augmentor section includes an igniter for igniting fuel injected into said exhaust stream.

5. The gas turbine engine as set forth in claim 1, wherein said at least two fan rotors include a variable inlet opening.

6. The gas turbine engine as set forth in claim 5, wherein said at least two fan rotors include a variable exhaust opening.

7. The gas turbine engine as set forth in claim 1, wherein said duct includes a first exit flow path when in said first position and a second exit flow path when in said second position, said first exit flow path being generally perpendicular to said second exit flow path.

8. The gas turbine engine as set forth in claim 1, wherein said gas generator includes at least two compressor rotors and at least two gas generator turbine rotors, with said fan drive turbine being positioned to be downstream of said path of said products of combustion having passed over each of said at least two gas generator turbine rotors.

9. The gas turbine engine as set forth in claim 1, wherein said axis of rotation of said gas generator is generally perpendicular to an axis of rotation of said shaft.

10. The gas turbine engine as set forth in claim 1, wherein said axis of rotation of said gas generator is generally coaxial with an axis of rotation of said at least two fan rotors.

11. The gas turbine engine of claim 1, wherein said fan drive turbine and said shaft are coaxial.

12. The gas turbine engine of claim 1, wherein said axis of rotation of said fan drive turbine is generally perpendicular to said at least two fan rotors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically shows a gas turbine engine.

(2) FIG. 2 is a front view of the FIG. 1 engine.

(3) FIG. 3 shows a first embodiment in a first configuration.

(4) FIG. 4 shows the first embodiment in a second configuration.

(5) FIG. 5 shows a dual configuration of FIG. 3.

(6) FIG. 6 shows a dual configuration of FIG. 4.

DETAILED DESCRIPTION

(7) A gas turbine engine 20 is illustrated in FIG. 1 having a gas generator 22. The gas generator 22 may be a two spool gas generator having a low speed spool in which a first upstream compressor rotor 24 driven by a downstream or low pressure turbine rotor 26. A high speed spool includes a high pressure compressor rotor 28 rotating with a high pressure or upstream turbine rotor 30. A combustion section 32 is positioned intermediate rotors 28 and 30.

(8) An exhaust duct 34 is positioned downstream of the gas generator 22 and receives products of combustion which have driven the turbine rotor 26 to rotate. These products of combustion pass across a fan drive turbine 36 mounted in a housing 37. The fan drive turbine 36 drives a single shaft 38 that engages a plurality of bevel gears 40 to, in turn, drive shafts 41 associated with fan rotors 42, 44, 46 and 48. Each of the fan rotors 42, 44, 46 and 48 are mounted within separate housings 50.

(9) By providing the single shaft 38, which drives at least four fan rotors and by utilizing a fan drive turbine 36 which is positioned downstream of the last turbine rotor 26 in the gas generator 22, this disclosure provides compact packaging, while still providing adequate drive for the fan rotors 42, 44, 46 and 48.

(10) FIG. 2 is a front view of an aircraft wing 80, which may mount an engine such as engine 20. As shown, the gas generator is associated with the housing 37. The fan rotors 42, 44, 46 and 48 have diameters that are not unduly large, such that they fit within the packaging window of associated wing 80.

(11) The basic engine as described above is disclosed in co-pending U.S. Patent Application Ser. No. 61/989,675, entitled Gas Turbine Engine With Distributed Fans, filed on May 7, 2014. This basic fan structure can be incorporated into a gas turbine engine arrangement having one or more gas generators, and paired sets of the distributed fan.

(12) As shown in FIGS. 3 and 4, a fan set 130 includes an engine 100 having a gas generator 102 for driving a fan drive turbine 104 or an augmentor 106. Products of combustion from the gas generator 102 are directed to the fan drive turbine 104 or the augmentor 106 by a moveable duct 108. An exhaust path when the moveable duct 108 is directed to the fan drive turbine 104 is generally perpendicular to an exhaust path when the moveable duct 108 is directed to the augmentor 106. In this embodiment, the moveable duct 108 is a three bearing swivel duct. However, other ducts capable of directing the products of combustion from the gas generator 102 to the fan drive turbine 104 and the augmentor 106 could be used.

(13) When the gas generator 102 is used to drive the fan drive turbine 104 as shown in FIG. 3, products of combustion from the gas generator 102 pass into an exhaust duct 110. A shaft 112 rotates about an axis Y, while the gas generator 102 rotates about an axis X. The axis X is generally perpendicular to the axis Y. Shafts 114 are driven by shaft 112 to turn fan rotors 116 and 118. The shafts 114 extend in a direction generally parallel to the axis X and perpendicular to the axis Y. Although the shaft 112 is shown turning two separate rotors 116 and 118, additional rotors could be turned by the shaft 112.

(14) A variable inlet 120 surrounds an inlet to the rotors 116 and 118 and a variable outlet 122 surrounds an outlet of the rotors 116 and 118 and the exhaust duct 110. When the moveable duct 108 engages the drive turbine 104 to turn the rotors 116 and 118, the variable inlet 120 and the variable outlet 122 are in an open position and an augmentor outlet 128 is in a closed position to reduce drag.

(15) When the gas generator 102 is used to drive the augmentor 106, the augmentor outlet 128 is opened and products of combustion from the gas generator 102 pass into an augmentor duct 126. The variable inlet 120 and the variable outlet 122 close to reduce drag.

(16) Fuel spray rails 124 extend into the flow path formed by the augmentor duct 126 to inject fuel which is ignited by an igniter 125 to produce an afterburner effect from the augmentor 106.

(17) FIG. 5 shows an arrangement using the two fan sets 130 with the moveable duct oriented to drive the fan drive turbine 104. Utilizing the two fan sets 130 in this orientation creates a higher propulsive efficiency with lower fuel consumption and exhaust temperatures for long range cruise situations.

(18) FIG. 6 shows an arrangement using the two fan sets 130 with the moveable ducts 108 oriented to engage the augmentors 106. Utilizing the two fan sets 130 in this orientation allows for supersonic or elevated speeds of travel with a higher fuel consumption than the arrangement shown in FIG. 5.

(19) The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.