Method of controlling fuel injection in a reheat combustor for a combustor unit of a gas turbine

1. A method of controlling fuel injection in a reheat combustor of a combustor assembly of a gas turbine, the reheat combustor having a combustor casing defining a gas flow channel and a combustion chamber, wherein the reheat combustor includes a plurality of injection units, each injection unit having a body extending across the gas flow channel along a first direction orthogonal to a gas flow direction and having a streamlined shape along the gas flow direction with a leading edge and a trailing edge and a plurality of fuel injection nozzles spaced along the first direction;

the plurality of injection units being spaced along a second direction orthogonal to the first direction and including at least one central injection unit and two lateral injection units disposed at opposite sides of the at least one central injection unit along the second direction,

wherein the method comprises:

receiving a fuel flow; and

distributing fuel among the injection nozzles according to a non-uniform distribution pattern,

wherein said distributing according to said non-uniform distribution pattern comprises:

applying different fuel supply rates between the two lateral injection units injecting fuel towards a propagation-stabilized flame region and the at least one central injection unit injecting fuel towards an auto-ignition stabilized flame region of the combustion chamber, wherein the fuel supply rate to each of the lateral injection units is greater than the fuel supply rate to the at least one central injection unit.

2. The method according to claim 1 , wherein said distributing according to said non-uniform distribution pattern comprises:

applying different individual fuel supply rates among the injection nozzles in at least one of the injection units.

3. The method according to claim 1 , wherein the at least one central injection unit includes at least two central injection units.

4. A reheat combustor, comprising:

a combustor casing defining a gas flow channel and a combustion chamber;

a plurality of side-by-side injection units, each injection unit having:

a body extending across the gas flow channel along a first direction orthogonal to a gas flow direction and having a streamlined shape along the gas flow direction with a leading edge and a trailing edge;

a plurality of fuel injection nozzles spaced along the first direction, the injection units being spaced along a second direction orthogonal to the first direction and including at least one central injection unit and two lateral injection units disposed at opposite sides of the at least one central injection unit along the second direction; and

a controller for controlling fuel supply rates to said injection nozzles,

wherein said controller is configured to distribute fuel among the injection nozzles according to a non-uniform distribution pattern,

wherein said non-uniform distribution pattern includes applying different fuel supply rates between the two lateral injection units injecting fuel towards a propagation-stabilized flame region and the at least one central injection unit injecting fuel towards an auto-ignition stabilized flame region of the combustion chamber, wherein said non-uniform distribution pattern includes applying a fuel supply rate to each of the lateral injection units which is greater than a fuel supply rate to the at least one central injection unit.

5. The reheat combustor according to claim 4 , wherein said non-uniform distribution pattern includes applying different individual fuel supply rates among the fuel nozzles in at least one of the injection units.

6. The reheat combustor according to claim 4 , wherein said injection units comprises:

integrated mixing devices configured for mixing an injected fuel with passing hot gas flow.

7. The reheat combustor according to claim 6 , wherein the mixing devices are vortex generators formed as lateral appendices extending from sides of the injection units upstream from each injection nozzle.

8. The reheat combustor according to claim 6 , wherein the mixing devices are lobes of a trailing edge of each injection unit forming an undulated profile thereof.

9. The reheat combustor according to claim 4 , wherein the at least one central injection unit includes at least two central injection units.