Dual-mode plug nozzle

Patent metadata

Field	Value
Publication number	US-2016123178-A1
Application number	US-201414894739-A
Country	US
Kind code	A1
Filing date	May 29, 2014
Priority date	May 31, 2013
Publication date	May 5, 2016
Grant date	—

Abstract

A variable geometry convergent-divergent nozzle for a gas turbine engine includes a centerbody extending rearward along a longitudinal axis of the engine which has a maximum diameter section. An inner shroud surrounds the centerbody and cooperates with the centerbody to define the throat of the nozzle. An outer shroud surrounds the inner shroud and cooperates with the centerbody to define the exit area of the nozzle. Both shrouds are independently translatable to provide independent control of the nozzle throat area and the nozzle expansion ratio. Additional actuation of the inner shroud results in the throat being disposed upon a fully forward portion of the centerbody, said fully forward shroud disposition being more forward than over the maximum diameter section. The nozzle may further comprise independent translation of the centerbody with respect to the shrouds.

First claim

What is claimed is:

1 . A method for controlling a fluid flow through a nozzle, comprising:
providing a centerbody extending rearward along a longitudinal axis, said centerbody including a maximum diameter section relative to the remainder of said centerbody; providing an inner shroud surrounding said centerbody, said inner shroud having an outer surface and an inner surface, said inner surface including at least a middle section of decreased diameter relative to the remainder of said inner surface; providing an outer shroud surrounding said inner shroud, said outer shroud having a forward edge, an aft edge, and an inner surface extending from said forward edge to said aft edge; providing means for independently selectively translating said inner and outer shrouds in forward and aft directions relative to said centerbody, wherein said centerbody and said inner shroud collectively define a throat area, of said nozzle, and said outer shroud and said centerbody collectively define an exit area, of said nozzle; selectively translating said inner shroud and outer shroud to vary said throat area, and, selectively translating said outer shroud to vary the ratio of said exit area to said throat area; wherein said inner shroud is movable between forward and aft positions, wherein additional actuation of said inner shroud results in said throat area, A8, being disposed upon a fully forward portion of the centerbody, said fully forward shroud disposition being more forward than over the maximum diameter section.

2 . The method of claim 1 wherein said throat area, is at a minimum size when said inner shroud is at said aft position, and said throat area, being at a maximum size for a converging-diverging nozzle when said inner shroud is in said forward position and is at a maximum size for a converging nozzle when said inner shroud is in furthest forward position.

3 . The method of claim 2 further comprising independent translation of said centerbody with respect to said shrouds.

4 . A nozzle for a gas turbine engine having a longitudinal axis, comprising:
a centerbody extending rearward along said longitudinal axis, said centerbody including a throat being a maximum diameter section relative to the remainder of said centerbody; an inner shroud surrounding said centerbody, said inner shroud having an outer surface and an inner surface, said inner surface including at least a middle section of decreased diameter relative to the remainder of said inner surface, said inner shroud being selectively moveable along said longitudinal axis in forward and aft directions relative to said centerbody; an outer shroud surrounding said inner shroud, said outer shroud having a forward edge, an aft edge, and an inner surface extending from said forward edge to said aft edge, said outer shroud being movable in forward and aft directions relative to said centerbody; and means for independently selectively moving said inner and outer shrouds in forward and aft directions relative to said centerbody, wherein said centerbody, said inner surface of said inner shroud, and said inner surface of said outer shroud collectively define a fluid flow path through said nozzle.

5 . The nozzle of claim 4 wherein said centerbody includes a forward section positioned forward of said maximum diameter section which tapers to a smaller diameter in a forward direction, and an aft section positioned aft of said maximum diameter section which tapers to a smaller diameter in a rearward direction.

6 . The nozzle of claim 5 further comprising independent translation of said centerbody with respect to said shrouds.

7 . A gas turbine engine having a longitudinal axis, comprising:
a nozzle comprising: a centerbody; an annular inner shroud having an outer surface and an inner surface, said inner surface including a middle section of decreased diameter relative to the remainder of said inner surface, said inner shroud selectively moveable along said longitudinal axis between forward and aft positions relative to said centerbody; an annular outer shroud having an inner surface and an outer surface, said outer shroud selectively movable between forward and aft positions relative to said centerbody; and means for independently translating said inner and outer shrouds.

8 . The gas turbine engine of claim 7 wherein said inner shroud is movable between forward and aft positions, and additional actuation of said inner shroud results in the throat area, A8, being disposed upon a fully forward portion of the centerbody, said fully forward shroud disposition being more forward than over the maximum diameter section.

9 . The gas turbine engine of claim 7 wherein said inner surface of said outer shroud defines a substantially constant cross-sectional area in from a forward edge thereof to an aft edge thereof.

10 . The gas turbine engine of claim 7 wherein said inner surface of said outer shroud has an arcuate cross-sectional profile such that the diameter of said inner surface at a forward edge thereof and an aft edge thereof is less than the diameter of said inner surface at a location between said forward and aft edges.

11 . The nozzle of the gas turbine having a longitudinal axis, according to claim 4 further comprising means for injecting a generally rearward-moving auxiliary fluid flow along said inner surface of said outer shroud.

12 . The nozzle of claim 4 wherein said centerbody, said inner shroud, and said outer shroud are bodies of revolution about said longitudinal axis, of said engine.

13 . The nozzle of claim 4 wherein said centerbody, said inner shroud, and said outer shroud are oval in cross-section.

Assignees

• Gen Electric

Inventors

• Tersmette Trevor Andrew
• Lee Jason Adam

Classifications

• F05D2250/41

  with one degree of freedom · CPC title

• F01D17/14 Primary

  varying effective cross-sectional area of nozzles or guide conduits · CPC title

• F05D2220/32

  in gas turbines · CPC title

• F01D9/02

  Nozzles; Nozzle boxes; Stator blades; Guide conduits {, e.g. individual nozzles (nozzle boxes F01D9/047)} · CPC title

• F02K1/09

  by axially moving an external member, e.g. a shroud (F02K1/12 takes precedence) · CPC title