PREMIX PILOT NOZZLE

• US 20160313006A1
• Filed: 04/21/2015
• Published: 10/27/2016
• Est. Priority Date: 04/21/2015
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: Stewart, Jason Thurman
• Granted Patent: US 9,803,867 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F23D 14/78 Cooling burner parts
• CPC Class Codes: F23R 2900/03343 Pilot burners operating in premixed mode
• CPC Class Codes: F23R 3/286 having fuel-air premixing devices F23R3/30 takes precedence
• CPC Class Codes: F23R 3/343 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

Abstract

A premix pilot nozzle includes a tip portion having a downstream surface that extends between a downstream end of an inner wall of the tip portion and a downstream end of an outer wall of the tip portion. The downstream end of the inner wall terminates axially upstream from the downstream end of the outer wall. At least a portion of the downstream surface is curvilinear. The tip portion further comprises a plurality of axially extending premix tubes annularly arranged about the tip portion. Each premix tube defines a premix flow passage through the tip portion. Each premix tube also includes an outlet that is axially offset from the downstream surface.

Claims

1. A premix pilot nozzle, comprising;

a tip portion having a downstream surface that extends between a downstream end of an inner wall of the tip portion and a downstream end of an outer wall of the tip portion, wherein the downstream end of the inner wall terminates axially upstream from the downstream end of the outer wall and wherein at least a portion of the downstream surface is curvilinear;

wherein the tip portion further comprises a plurality of axially extending premix tubes annularly arranged about the tip portion, wherein each premix tube defines a premix flow passage through the tip portion, and wherein each premix tube includes an outlet axially offset from the downstream surface.

2. The premix pilot nozzle as in claim 1, wherein at least a portion of the downstream surface extends concavely between the downstream end of the inner wall and the downstream end of the outer wall.

3. The premix pilot nozzle as in claim 1, wherein the downstream surface curves at least partially around each of the premix tubes.

4. The premix pilot nozzle as in claim 1, wherein adjacent premix tubes define a cooling flow channel therebetween along the downstream surface.

5. The premix pilot nozzle as in claim 1, wherein the tip portion at least partially defines a fuel circuit within a center body of a fuel nozzle assembly, wherein each premix tube is in fluid communication with the fuel circuit.

6. The premix pilot nozzle as in claim 1, wherein each premix tube includes a bridge portion that is connected to the outer wall of the tip portion.

7. The premix pilot nozzle as in claim 1, wherein at least one of the premix tubes terminates adjacent to the downstream end of the outer wall.

8. The premix pilot nozzle as in claim 1, wherein at least one of the premix tubes terminates downstream from the downstream end of the outer wall.

9. The premix pilot nozzle as in claim 1, wherein the inner wall of the tip portion at least partially defines a cartridge opening.

10. A fuel nozzle assembly, comprising:

a center body that extends axially along a center line of the fuel nozzle assembly, the center body having a pilot fuel circuit and a pilot air circuit defined therein;

a premix pilot nozzle that extends axially within the center body, the premix pilot nozzle having a tip portion, the tip portion comprising a downstream surface that extends between a downstream end of an inner wall of the tip portion and a downstream end of an outer wall of the tip portion, wherein the downstream end of the inner wall terminates axially upstream from the downstream end of the outer wall and wherein at least a portion of the downstream surface is curvilinear;

wherein the tip portion further comprises a plurality of axially extending premix tubes annularly arranged about the tip portion, wherein each premix tube includes an outlet axially offset from the downstream surface and wherein each tube defines a premix flow passage through the tip portion that terminates downstream from the downstream surface.

11. The fuel nozzle assembly as in claim 10, wherein at least a portion of the downstream surface extends concavely between the downstream end of the inner wall and the downstream end of the outer wall.

12. The fuel nozzle assembly as in claim 10, wherein the downstream surface curves at least partially around each of the premix tubes.

13. The fuel nozzle assembly as in claim 10, wherein adjacent premix tubes define a cooling flow channel therebetween along the downstream surface.

14. The fuel nozzle assembly as in claim 10, wherein the tip portion at least partially defines a fuel circuit within a center body of a fuel nozzle assembly, wherein each premix tube is in fluid communication with the fuel circuit.

15. The fuel nozzle assembly as in claim 10, wherein each premix tube includes a bridge portion that is connected to the outer wall of the tip portion.

16. The fuel nozzle assembly as in claim 10, wherein at least one of the premix tubes terminates adjacent to the downstream end of the outer wall.

17. The fuel nozzle assembly as in claim 10, wherein at least one of the premix tubes terminates downstream from the downstream end of the outer wall.

18. The fuel nozzle assembly as in claim 10, further comprising a cartridge that extends axially within the center body and the premix pilot nozzle, wherein the cartridge is configured to provide a cooling medium to the downstream surface of the tip portion of the premix pilot nozzle.

19. The fuel nozzle assembly as in claim 10, further comprising an outer sleeve coaxially aligned with the center body, wherein center body and the outer sleeve define an annular passage therebetween, the fuel nozzle further comprising a plurality of swirler vanes that extend between the center body and the outer sleeve within the annular passage.

20. A combustor comprising:

an end cover;

a plurality of fuel nozzle assemblies annularly arranged about a center fuel nozzle, each fuel nozzle assembly of the plurality of fuel nozzle assemblies and the center fuel nozzle being fixedly connected to the end cover, wherein at least one fuel nozzle assembly comprises;

a center body that extends axially along a center line of the fuel nozzle assembly, the center body having a pilot fuel circuit and a pilot air circuit defined therein;

a premix pilot nozzle that extends axially within the center body, the premix pilot nozzle having a tip portion, the tip portion comprising a downstream surface that extends between a downstream end of an inner wall of the tip portion and a downstream end of an outer wall of the tip portion, wherein the downstream end of the inner wall terminates axially upstream from the downstream end of the outer wall and wherein at least a portion of the downstream surface is curvilinear;

wherein the tip portion further comprises a plurality of axially extending premix tubes annularly arranged about the tip portion, wherein each premix tube includes an outlet axially offset from the downstream surface and wherein each tube defines a premix flow passage through the tip portion that terminates downstream from the downstream surface.