Gas turbine and fuel injector for the same

A method of operating a gas turbine engine comprising:

• directing a gaseous fuel into a combustor of the gas turbine engine through a central cavity of a fuel injector substantially unmixed with compressed air, the central cavity extending longitudinally from an upstream end to a downstream end fluidly coupled to the combustor;
• directing compressed air into the combustor circumferentially about the central cavity;
• and
• directing a second fuel into the combustor circumferentially about the compressed air, wherein directing the second fuel includes increasing an angular velocity of the second fuel in the fuel injector.

A gas turbine engine, comprising:

• a compressor system;
• a turbine system;
• a combustor system including a combustor;
• and
• a fuel injector extending from an upstream end to a downstream end, the fuel injector being coupled to the combustor at the downstream end, the fuel injector including:
• a central cavity extending from the upstream end to the downstream end along a longitudinal axis, the central cavity being configured to direct a gaseous fuel into the combustor substantially unmixed with compressed air;
• an annular inner passageway extending from the upstream end to the downstream end, the downstream end of the inner air passageway including an air discharge outlet, the inner passageway being disposed symmetrically about the central cavity, and the air discharge outlet being configured to direct compressed air into the combustor circumferentially about the gaseous fuel entering the combustor through the central cavity;
• and
• an annular outer passageway circumferentially disposed about the annular inner passageway, the outer passageway being configured to direct a liquid fuel into the combustor circumferentially about the compressed air entering the combustor through the air discharge outlet.