Patent ID: 9366443
Filing Date: 2016-06-14
CPC Classification: F23R

Claim Text:
1. A method for axial stage combustion in a gas turbine engine comprising: mixing air and fuel to form a lean air-fuel mixture of air and fuel in a first stage of combustion of a can-annular combustor of the gas turbine engine, wherein the lean air-fuel mixture of air and fuel has an equivalence ratio of less than one; igniting the lean air-fuel mixture at the first stage of combustion to create hot combustion gas having a first temperature and free radicals; disposing an air-fuel mixing arrangement in a second stage of combustion of the can-annular combustor, the second stage of combustion located downstream from the first stage of combustion, the air-fuel mixing arrangement coupled to receive fuel delivered in the second stage of combustion by a plurality of fuel nozzles and further coupled to receive a flow of air in the second stage of combustion; mixing air and fuel received by the air-fuel mixing arrangement to form a rich air-fuel mixture of air and fuel in the second stage of combustion, wherein the rich air-fuel mixture of air and fuel has an equivalence ratio of greater than one; wherein the mixing of air and fuel received by the air-fuel mixing arrangement comprises adjustably varying a volumetric flow rate of fuel delivered in the second stage of combustion by the fuel nozzles by way of respective valves in each fuel nozzle to adjustably vary the equivalence ratio of the rich air-fuel mixture, injecting the rich air-fuel mixture into the second stage of combustion; and igniting the rich air-fuel mixture in the hot combustion gas at the second stage of combustion, such that the first temperature and the free radicals of the hot combustion gas promote combustion of the rich air-fuel mixture within a predetermined hydrocarbon emissions limit, and the first temperature of the hot combustion gas increases to a second temperature.