Self-purging pilot fuel injection system

1. A self-purging pilot fuel injection system, said injection system comprising:

A radial inflow swirler, said swirler having at least one set of swirlers oriented generally perpendicular to a combustor centerline;

An end plate having a generally axially extending centerbody, the axially extending centerbody located substantially along said combustor centerline and having an outer surface;

A first fuel supply located in said end plate;

A plurality of first fuel injection orifices that are operable to inject fuel parallel to the combustor centerline, the plurality of first fuel injection orifices located along the axially extending centerbody outer surface in a direction generally parallel to the combustor centerline, said first plurality of fuel injection orifices for supplying fuel from said first fuel supply to a region immediately adjacent said center body;

A second fuel supply located in said end plate radially outward of said first fuel supply;

A plurality of second fuel injection orifices that are operable to inject fuel perpendicular to the combustor centerline, the plurality of second fuel injection orifices located proximate said swirler and oriented generally perpendicular to the combustor centerline for supplying fuel from said second fuel supply to a stream of air passing through said swirler; and,

Wherein a fluid containing at least air passes along said outer surface and over said plurality of first fuel injection orifices in a manner so as to prevent flame attachment proximate said plurality of first fuel injection orifices.

2. The self-purging pilot fuel injection system of claim 1 wherein the axially extending centerbody extends axially downstream past said plurality of first fuel injection orifices.

3. The self-purging pilot fuel injection system of claim 1 wherein the axially extending centerbody is generally circular in shape.

4. The self-purging pilot fuel injection system of claim 1 further comprising an ignition source extending through the axially extending centerbody.

5. The self-purging pilot fuel injection system of claim 4 wherein said ignition source is a torch igniter or a spark igniter.

6. The self-purging pilot fuel injection system of claim 1 wherein said first fuel supply and said second fuel supply are generally annular manifolds in said end plate about said combustor centerline.

7. The self-purging pilot fuel injection system of claim 1 wherein said first fuel supply is gas.

8. The self-purging pilot fuel injection system of claim 1 wherein said outer surface tapers from parallel to said combustor centerline to perpendicular to said combustor centerline.

9. The self-purging pilot fuel injection system of claim 1 wherein said fluid contains a mixture of fuel and air.

10. A self-purging pilot fuel injection system, said injection system comprising:

A radial inflow swirler, said swirler having at least one set of swirlers oriented generally perpendicular to a combustor centerline;

An end plate having a generally axially extending centerbody, the axially extending centerbody located substantially along said combustor centerline and having an outer surface;

A first fuel supply located in said end plate;

A plurality of first fuel injection orifices that are operable to inject fuel parallel to the combustor centerline, the plurality of first fuel injection orifices located along the axially extending centerbody outer surface for supplying fuel from said first fuel supply to a region immediately adjacent the axially extending centerbody, said first fuel injection orifices oriented generally parallel to the combustor centerline; and

A plurality of second fuel injection orifices that are operable to inject fuel generally perpendicular to the combustor centerline, the plurality of second fuel injection orifices located proximate said swirler and oriented generally perpendicular to the combustor centerline; and

Wherein a fluid containing at least air passes along said outer surface and over said plurality of first fuel injection orifices in a manner so as to prevent flame attachment proximate said plurality of first fuel injection orifices.

11. The self-purging pilot fuel injection system of claim 10 wherein said injection system further comprises a second fuel supply located in said end plate radially outward of said first fuel supply.

12. The self-purging pilot fuel injection system of claim 11 wherein said plurality of second fuel injection orifices for supplying fuel from said second fuel supply to a stream of air passing through said swirler.

13. The self-purging pilot fuel injection system of claim 10 wherein the axially extending centerbody extends axially downstream past said plurality of first fuel injection orifices.

14. The self-purging pilot fuel injection system of claim 13 wherein said outer surface tapers from parallel to said combustor centerline to perpendicular to said combustor centerline.

15. The self-purging pilot fuel injection system of claim 10 wherein the axially extending centerbody is generally circular in shape.

16. The self-purging pilot fuel injection system of claim 10 further comprising an ignition source extending through the axially extending centerbody.

17. The self-purging pilot fuel injection system of claim 16 wherein said ignition source is a torch igniter or a spark igniter.

18. A method of purging a pilot fuel injection system, said method comprising the steps:

Providing a pilot fuel injection system for a gas turbine combustor comprising:

(a) A radial inflow swirler, said swirler having at least one set of swirlers oriented generally perpendicular to a combustor centerline, wherein the combustor centerline is orientated axially in relation to a combustor liner of the gas turbine combustor;

(b) An end plate having a generally axially extending centerbody, the axially extending centerbody located substantially along said combustor centerline and having an outer surface;

(c) An ignition source;

(d) A first fuel supply located in said end plate; and

(e) A plurality of first fuel injection orifices that are operable to inject fuel parallel to the combustor centerline, the plurality of first fuel injection orifices located in the axially extending centerbody outer surface, in fluid communication with said first fuel supply, and oriented in a direction generally parallel to the combustor centerline;

Directing a flow of fuel through said plurality of first fuel injection orifices and generally along the axially extending centerbody outer surface;

Igniting said fuel at a region proximate to the axially extending centerbody; and

Flowing a fluid containing at least air along said outer surface and generally perpendicular across said plurality of first fuel injection orifices such that a flame cannot attach proximate said plurality of first fuel injection orifices.