Hybrid air blast fuel nozzle

Patent metadata

Field	Value
Publication number	US-2016265778-A1
Application number	US-201514643335-A
Country	US
Kind code	A1
Filing date	Mar 10, 2015
Priority date	Mar 10, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

A fuel nozzle apparatus for a gas turbine engine includes: a first pilot fuel injector disposed on a centerline axis of the fuel nozzle which defines a direction of air flow through the fuel nozzle, the first pilot fuel injector being of a pressure atomizing type; an annular second pilot fuel injector at least partially surrounding the first pilot fuel injector, the second pilot fuel injector being of an air blast type and having a fuel outlet disposed axially downstream and radially outboard of the first pilot fuel injector; an annular venturi surrounding the first and second pilot fuel injectors, the venturi including a throat of minimum diameter; an array of inner swirl vanes extending between the first pilot fuel injector and the second pilot fuel injector; and an array of outer swirl vanes extending between the second pilot fuel injector and the venturi.

First claim

What is claimed is:

1 . A fuel nozzle apparatus for a gas turbine engine, comprising:
a first pilot fuel injector disposed on a centerline axis of the fuel nozzle which defines a direction of air flow through the fuel nozzle, the first pilot fuel injector being of a pressure atomizing type; an annular second pilot fuel injector at least partially surrounding the first pilot fuel injector, the second pilot fuel injector being of an air blast type and having a fuel outlet disposed axially downstream and radially outboard of the first pilot fuel injector; an annular venturi surrounding the first and second pilot fuel injectors, the venturi including a throat of minimum diameter; an array of inner swirl vanes extending between the first pilot fuel injector and the second pilot fuel injector; and an array of outer swirl vanes extending between the second pilot fuel injector and the venturi.

2 . The apparatus of claim 1 wherein the second pilot fuel injector includes an annular fuel manifold defined therein which communicates with the fuel outlet.

3 . The apparatus of claim 2 wherein an annular inner heat shield is disposed radially inboard of the fuel manifold, separated from the fuel manifold by an air space.

4 . The apparatus of claim 2 wherein an annular outer heat shield is disposed radially outboard of the fuel manifold, separated from the fuel manifold by an air space.

5 . The apparatus of claim 1 wherein an array of mid swirl vanes is disposed radially between the fuel outlet and either the inner swirl vanes or the outer swirl vanes.

6 . The apparatus of claim 1 wherein at least some of the swirl vanes have a helical or partially-helical shape.

7 . The apparatus of claim 5 wherein the mid swirl vanes are disposed radially between the fuel outlet and the inner swirl vanes.

8 . The apparatus of claim 5 wherein the mid swirl vanes are disposed radially between the fuel outlet and the outer swirl vanes.

9 . The apparatus of claim 1 wherein the second pilot fuel injector includes an inner surface having, in axial sequence from front to rear: a generally cylindrical upstream section, a throat of minimum diameter, and a downstream diverging section.

10 . The apparatus of claim 9 wherein the fuel outlet intersects the diverging section of the inner surface.

11 . The apparatus of claim 9 wherein the second pilot fuel injector includes:
an annular fuel manifold defined therein which communicates with the fuel outlet;
an annular inner heat shield disposed radially inboard of the fuel manifold, separated from the fuel manifold by an air space;
an annular outer heat shield disposed radially outboard of the fuel manifold, separated from the fuel manifold by an air space;
an annular inner wall disposed radially inboard of the inner heat shield, the inner wall defining the inner surface; and
an array of mid swirl vanes extending between the inner heat shield and the inner wall.

12 . The apparatus of claim 1 wherein the second pilot fuel injector includes an outer surface having, in axial sequence from front to rear: a generally cylindrical upstream section, and a downstream converging section.

13 . The apparatus of claim 12 wherein the second pilot fuel injector includes:
an annular fuel manifold defined therein which communicates with the fuel outlet;
an annular inner heat shield disposed radially inboard of the fuel manifold, separated from the fuel manifold by an air space;
an annular outer heat shield disposed radially outboard of the fuel manifold, separated from the fuel manifold by an air space;
an annular outer wall disposed radially outboard of the outer heat shield, the outer wall defining the outer surface; and
an array of mid swirl vanes extending between the outer heat shield and the outer wall.

14 . The apparatus of claim 1 wherein at least some of the vanes have a helical or partially-helical shape.

15 . A fuel nozzle apparatus including:
the apparatus of claim 1 ; an annular outer body surrounding the pilot fuel injectors, the outer body extending parallel to the centerline axis, the outer body having a generally cylindrical exterior surface extending between forward and aft ends, and having a plurality of openings passing through the exterior surface; an annular main injection ring disposed inside the outer body, the main injection ring including an annular array of main fuel orifices, each main fuel orifice being aligned with one of the openings in the outer body; and a main fuel gallery extending within the main injection ring in a circumferential direction and communicating with the plurality of main fuel orifices.

16 . The apparatus of claim 15 further including:
a fuel system operable to supply a flow of liquid fuel at varying flowrates;
a pilot primary fuel conduit coupled between the fuel system and the first pilot fuel injector;
a pilot secondary fuel conduit coupled between the fuel system and the second pilot fuel injector; and
a main fuel conduit coupled between the fuel system and the main injection ring.

Assignees

• Gen Electric

Inventors

• Patel Nayan Vinodbhai
• Thomsen Duane Douglas

Classifications

• F23R3/286 Primary

  having fuel-air premixing devices (F23R3/30 takes precedence) · CPC title

• F23R3/28 Primary

  characterised by the fuel supply (burners F23D) · CPC title

• F23D11/24

  by pressurisation of the fuel before a nozzle through which it is sprayed by a substantial pressure reduction into a space · CPC title

• F23D2900/11101

  Pulverising gas flow impinging on fuel from pre-filming surface, e.g. lip atomizers · CPC title

• F23R3/343

  Pilot flames, i.e. fuel nozzles or injectors using only a very small proportion of the total fuel to insure continuous combustion (ignition in gas-turbine plants F02C7/264; pilot flame igniters F23Q9/00) · CPC title