Patent ID: 7137256
Filing Date: 2006-11-21
Classification: F02C,F23R

Abstract:
1. A method of operating a combustion system of a gas turbine engine, said method comprising: a). providing a combustion system comprising a plurality of first stage injectors arranged in a first array about a center axis, a plurality of second stage injectors arranged in a second array radially outward of said first injectors proximate a first swirler, an aft injector assembly comprising a manifold having a plurality of third stage injectors and a plurality of fourth stage injectors, said plurality of third stage and fourth stage injectors arranged in sectors of said aft injector assembly, and a spark ignition source located within said combustion system; b). supplying a fuel to said plurality of first stage injectors and said plurality of second stage injectors at a fuel flow split and injecting said fuel into a surrounding air flow to form a mixture, and igniting said mixture with said spark ignition source; c). gradually increasing fuel flow split to said plurality of first stage injectors while gradually decreasing fuel flow split to said plurality of second stage injectors until all fuel to said combustion system is flowing through said plurality of first stage injectors at engine full speed no load condition; d). maintaining said fuel flow split to said plurality of first stage injectors until a first part-load condition; e). at said first part-load condition, gradually decreasing said fuel flow split to said plurality of first stage injectors while gradually increasing said fuel flow split to said plurality of second stage injectors until all fuel to said combustion system is flowing through said plurality of second stage injectors at a second part-load condition; f). maintaining said fuel flow split to said plurality of second stage injectors until a third part-load condition; g). at said third part-load condition, reducing said fuel flow split to said plurality of second stage injectors while increasing fuel flow split to said plurality of third stage injectors; h). gradually decreasing said fuel flow split to said plurality of second stage injectors while gradually increasing said fuel flow split to said plurality of third stage injectors until a fourth part load condition; i). At said fourth part load condition, reducing said fuel flow split to both said plurality of second stage injectors and said plurality of third stage injectors while increasing fuel flow split to said plurality of fourth stage injectors; and, j). maintaining said fuel flow split to said plurality of second stage, third stage, and fourth stage injectors until said gas turbine engine reaches a full load condition.