VARIABLE FLOW DIVIDER MECHANISM FOR A MULTI-STAGE COMBUSTOR

1 . A flow divider mechanism comprising an annular plate positioned about a combustion liner for dividing airflow into a pilot stage and a main combustion stage of a gas turbine combustor, the annular plate having a central opening, an outer edge, a first plurality of openings located about the central opening, a second plurality of openings located radially outward of the first plurality of openings, and a third plurality of openings located adjacent the outer edge, wherein the first plurality of openings and second plurality of openings are sized to regulate and direct a predetermined amount of airflow through multiple stages of the gas turbine combustor.

2 . The flow divider mechanism of claim 1 , wherein the second plurality of openings are offset circumferentially from the first plurality of openings.

3 . The flow divider mechanism of claim 1 , wherein compressed air for use in generating a main stage combustion flame passes through the first plurality of openings in the annular plate.

4 . The flow divider mechanism of claim 3 , wherein compressed air for use in generating and supporting a pilot flame passes through the second plurality of openings in the annular plate.

5 . The flow divider mechanism of claim 1 further comprising a flow separator extending co-annular with the annular plate and perpendicular relative to the annular plate.

6 . The flow divider mechanism of claim 1 , wherein the third plurality of openings are used for clocking and securing the flow divider mechanism to the gas turbine combustor.

7 . The flow divider mechanism of claim 1 , wherein the first plurality of openings are in alignment with a corresponding main stage mixing vane.

8 . A multi-stage combustion system for directing a predetermined amount of compressed air from outside of a combustion liner to multiple stages within the combustion liner, the combustion system comprising:

a flow sleeve surrounding the combustion liner;

a flow divider mechanism positioned axially between the flow sleeve and a main injector, the flow divider mechanism comprising an annular plate positioned about the combustion liner for dividing airflow passing between the flow sleeve and the combustion liner into a first portion and a second portion, the annular plate having a central opening, an outer edge, a first plurality of openings located about the central opening, a second plurality of openings located radially outward of the first plurality of openings, a third plurality of openings located adjacent an outer edge; and

a cylindrical flow separator extending from the annular plate and towards an inlet end of the combustion liner;

wherein compressed air passing between an outer wall of the combustion liner and the flow sleeve is split into two portions, with a first portion directed through the first plurality of openings and a second portion directed through the second plurality of openings, the first portion supplying compressed air to a main stage of combustion and the second portion supplying air to a pilot stage.

9 . The combustion system of claim 8 further comprising a dome having a hemispherical portion which causes a reversal in flow direction of the first portion of compressed air.

10 . The combustion system of claim 9 , wherein the first portion of compressed air passes along an outer wall of the combustion liner when external to the combustion liner and along an inner wall of the combustion liner after encountering the dome.

11 . The combustion system of claim 10 , wherein the second portion of compressed air passes radially outward of the first portion of compressed air when external to the combustion liner and radially inward of the first portion of compressed air when internal of the combustion liner.

12 . The combustion system of claim 8 , wherein the first plurality of openings are in airflow alignment with a corresponding main stage mixing vane.

13 . The combustion system of claim 8 , wherein the flow divider mechanism is secured to the combustion system using the third plurality of openings.

14 . The combustion system of claim 13 , wherein the flow divider mechanism is interchangeable upon disengagement of surrounding combustion hardware and fasteners securing the flow divider mechanism to the combustion system.

15 . A method of altering an airflow distribution between multiple stages of a combustion system comprising:

providing a combustion system having a first flow divider mechanism in which compressed air for use in combustion is divided into a first portion and a second portion by an annular plate having a first plurality of openings and a second plurality of openings;

removing a cover, dome, main fuel injector, and pilot nozzle from the combustion system;

removing fasteners securing the first flow divider to the combustion system;

removing the first flow divider;

placing a second flow divider on the combustion system, the second flow divider having a first plurality of openings and a second plurality of openings, where at least one of the first plurality of openings or the second plurality of the second flow divider differs from the first plurality of openings or a second plurality of openings of the first flow divider;

securing the second flow divider to the combustion system; and

securing the cover, dome, main fuel injector and pilot nozzle to the combustion system such that the second flow divider is positioned axially between flanges of the main fuel injector and a flow sleeve.

16 . The method of claim 15 , wherein the second plurality of openings in the second flow divider has an effective flow area greater than an effective flow area for the second plurality of openings in the first flow divider.

17 . The method of claim 15 , wherein the second plurality of openings in the second flow divider has an effective flow area less than an effective flow area for the second plurality of openings in the first flow divider.

18 . The method of claim 15 , wherein the first plurality of openings in the second flow divider has an effective flow area greater than an effective flow area for the first plurality of openings in the first flow divider.

19 . The method of claim 15 , wherein the first plurality of openings in the second flow divider has an effective flow area less than an effective flow area for the first plurality of openings in the first flow divider.