Flamesheet combustor dome

1. A gas turbine combustor comprising:

a generally cylindrical flow sleeve extending along a combustor axis;

a generally cylindrical combustion liner located coaxial to and radially within the flow sleeve, the combustion liner having an inlet end and an opposing outlet end;

a set of main fuel injectors positioned radially outward of the combustion liner and proximate an upstream end of the flow sleeve;

a combustor dome assembly encompassing the inlet end of the combustion liner, the dome assembly extending from proximate the set of main fuel injectors to a generally hemispherical-shaped cap positioned a distance forward of the inlet end of the combustion liner and turns to extend a distance into the combustion liner, such that a first passageway and a second passageway are formed between the combustion liner and a dome assembly outer wall and a third passageway is formed between the combustion liner and a dome assembly inner wall, where the first passageway has a first radial height, the second passageway has a second radial height and the third passageway has a third radial height such that the second radial height regulates the volume of a fuel-air mixture entering the gas turbine combustor;

wherein the first radial height ranges from approximately 15 millimeters to approximately 50 millimeters;

wherein the second radial height ranges from approximately 10 millimeters to approximately 45 millimeters; and

wherein the third radial height ranges from approximately 30 millimeters to approximately 100 millimeters, such that the first passageway tapers towards the second passageway to accelerate the fuel-air mixture to achieve adequate flashback margin velocity of 40-80 meters per second to generate a trapped vortex adjacent the combustor liner.

2. The gas turbine combustor of claim 1 , further comprising a fourth passageway having a fourth height as measured between the inlet end of the combustion liner and the combustor dome assembly.

3. The gas turbine combustor of claim 1 , wherein the largest height of the first passageway occurs at a region adjacent the set of main fuel injectors.

4. The gas turbine combustor of claim 1 , wherein the second and third passageways are cylindrical.

5. A method of controlling a velocity of a fuel-air mixture for a gas turbine combustor comprising:

directing a fuel-air mixture through a first passageway located radially outward of a combustion liner, the first passageway having a first radial height;

directing the fuel-air mixture from the first passageway and into a second passageway located radially outward of the combustion liner, the second passageway having a second radial height;

directing the fuel-air mixture from the second passageway into a fourth passageway in a hemispherical dome cap, thereby causing the fuel-air mixture to reverse flow direction; and

directing the fuel-air mixture through a third passageway located within the combustion liner and into the combustion liner, the third passageway having a third radial height;

wherein the first radial height ranges from approximately 15 millimeters to approximately 50 millimeters;

wherein the second radial height ranges from approximately 10 millimeters to approximately 45 millimeters;

wherein the third radial height ranges from approximately 30 millimeters to approximately 100 millimeters such that a ratio of the second radial height to the third radial height is approximately 0.1 to 0.5; and

wherein the first passageway has a conical-shaped cross section that tapers towards the second passageway;

wherein the second passageway has a cylindrical-shaped cross section; and

wherein the third passageway has a cylindrical-shaped cross section.

6. The method of claim 5 , wherein the second passageway contains a minimal cross sectional area between the first, second and third passageways.

7. The method of claim 5 , wherein the ratio of the second radial height to the third radial height generates a trapped vortex.

8. The method of claim 5 , wherein a wall of the combustion liner forms parts of the first, second and third passageways.