Burner

Patent metadata

Field	Value
Publication number	US-11204165-B2
Application number	US-201916390548-A
Country	US
Kind code	B2
Filing date	Apr 22, 2019
Priority date	May 18, 2018
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

Abstract

There is provided a burner for a gas turbine engine, the burner comprising a radially inner pilot fuel flow passage surrounded by a radially outer main fuel flow passage. The main fuel flow passage is interposed between concentrically arranged radially inner and radially outer air flow passages. The inner and outer air flow passages are in fluid communication with one another via at least one diverting passage at an upstream end of the burner. The burner further comprises at least one control duct connectable to a reduced pressure/vacuum source for selectively reducing the air pressure in the vicinity of the diverting passage such that air flow is selectively diverted from the inner air flow passage to the outer flow passage via the diverting passage.

First claim

I claim:

1. A burner for a gas turbine engine, the burner comprising a radially inner pilot fuel flow passage surrounded by a radially outer main fuel flow passage, the radially outer main fuel flow passage being interposed between concentrically arranged radially inner and radially outer air flow passages such that a main fuel flow is separate from the radially inner and radially outer air flow passages, wherein the radially inner and outer air flow passages are in fluid communication with one another via at least one diverting passage at an upstream end of the burner, and wherein the burner further comprises at least one control duct connectable to a reduced pressure/vacuum source for selectively reducing an air pressure in a vicinity of the at least one diverting passage such that air flow is selectively diverted from the radially inner air flow passage to the radially outer flow passage via the at least one diverting passage so as to allow a pilot fuel flow flowing through the inner pilot fuel flow passage and the main fuel flow to merge faster than when the air flow is not selectively diverted from the radially inner air flow passage to the radially outer flow passage.

2. The burner of claim 1 , wherein the at least one control duct is additionally connectable to an increased pressure air supply.

3. The burner of claim 1 , wherein the at least one control duct extends to a circumferentially-extending annular chamber, the circumferentially-extending annular chamber having at least one opening in the vicinity of the at least one diverting passage.

4. A burner for a gas turbine engine, the burner comprising a radially inner pilot fuel flow passage surrounded by a radially outer main fuel flow passage, the main fuel flow passage being interposed between concentrically arranged radially inner and radially outer air flow passages such that a main fuel flow is separate from the radially inner and radially outer air flow passages,
wherein the radially inner and outer air flow passages are in fluid communication with one another via at least one diverting passage at an upstream end of the burner,
wherein the burner further comprises at least one control duct connectable to a reduced pressure/vacuum source for selectively reducing an air pressure in a vicinity of the at least one diverting passage such that air flow is selectively diverted from the radially inner air flow passage to the radially outer flow passage via the at least one diverting passage so as to allow a pilot fuel flow flowing through the inner pilot fuel flow passage and the main fuel flow to merge faster than when the air flow is not selectively diverted from the radially inner air flow passage to the radially outer flow passage,
wherein the at least one control duct extends to a circumferentially-extending annular chamber, the circumferentially-extending annular chamber having at least one opening in the vicinity of the at least one diverting passage, and
wherein the at least one opening is at or proximal an interface between the at least one diverting passage and the radially inner air flow passage.

5. The burner of claim 3 , wherein the at least one opening includes a plurality of openings.

6. The burner of claim 5 , wherein the plurality of openings are equally spaced around a circumference of the circumferentially-extending annular chamber.

7. The burner of claim 5 , wherein a circumferential spacing between the plurality of openings and/or a density of the plurality of openings vary around a circumferential direction.

8. The burner of claim 7 , wherein the circumferentially-extending annular chamber comprises a first quadrant and diametrically opposed third quadrant each having a first spacing between adjacent openings of the plurality of openings, the first and third quadrants between interposed by diametrically opposed second and fourth quadrants each having a second, larger spacing between adjacent openings of the plurality of openings.

9. The burner of claim 5 , wherein there is a single, circumferentially-extending diverting passage which is divided into a plurality of circumferentially-extending sections and wherein at least one section of the diverting passage is bounded at an area of variation in a density of the plurality of openings around the inner air flow passage.

10. The burner of claim 3 , wherein the circumferentially-extending annular chamber is axially divided into a plurality of circumferentially-extending sections.

11. The burner of claim 3 , wherein there is a single, circumferentially-extending diverting passage which is divided into a plurality of circumferentially-extending sections.

12. The burner of claim 1 , wherein the at least one diverting passage extends in an oblique direction from the radially inner air flow passage to the radially outer air flow passage.

13. The burner of claim 1 , wherein at least one of the radially inner and outer air flow channels contains a respective swirl generator downstream of the at least one diverting passage.

14. The burner of claim 1 , further comprising:
a single fuel supply duct feeding both of the radially inner pilot and radially outer main fuel flow channels; and
a burner stem arranged radially outward of the at least one diverting passage,
wherein the single fuel supply duct and the at least one control duct are arranged within the burner stem.

15. A method of controlling a combustion cycle of a combustion system in a gas turbine engine, the combustion system comprising at least one burner having a radially inner pilot fuel flow and a radially outer main fuel flow, the radially outer main fuel flow being interposed between concentrically arranged radially inner and radially outer air flow passages such that the main fuel flow is separate from the radially inner and radially outer air flow passages, the method comprising selectively increasing air flow in the radially outer air flow passage relative to air flow in the radially inner air flow passage by diverting the air flow from the radially inner air flow passage to the radially outer air flow passage through at least one diverting passage provided in an upstream end of the at least one burner so as to allow the radially inner pilot fuel flow and the main fuel flow to merge faster than when the air flow in the radially outer air flow passage is not selectively increased, or selectively increasing the air flow in the radially inner air flow passage relative to the air flow in the radially outer air flow passage by diverting the air flow from the radially outer air flow passage to the radially inner air flow passage through the at least one diverting passage so as to allow the radially inner pilot fuel flow and the radially outer main fuel flow to remain separated longer than when the air flow is not selectively increased in the radially inner air flow passage.

16. The method of claim 15 , comprising diverting the air flow from the radially inner air flow passage to the radially outer air flow passage through the at least one diverting passage by selectively reducing an air pressure in a vicinity of the at least one diverting passage using a reduced pressure/vacuum source.

17. The method of claim 16 , wherein the method further comprises selectively increasing the air flow in the radially inner air flow passage relative to the air flow in the radially outer air flow passage by selectively increasing the air pressure in the vicinity of the at least one diverting passage using an increased pressure air supply.

18. The method of claim 15 , wherein the method comprises reducing or increas

Assignees

• Rolls Royce Plc

Inventors

• Bellis Mark Je

Classifications

• 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

• F23R3/26 Primary

  Controlling the air flow · CPC title

• F23R3/02

  characterised by the air-flow or gas-flow configuration (reverse- flow combustion chambers F23R3/54; cyclone or vortex type combustion chambers F23R3/58) · CPC title

• F23C7/006

  adjustable · CPC title

• F23R3/14

  by using swirl vanes · CPC title