Abstract: A fuel injector for a gas turbine engine includes a stem extending along a longitudinal axis from a proximal end to a distal end. The stem includes one or more fuel tubes configured to deliver a fuel toward the distal end of the stem, and a pilot assembly coupled to the distal end of the stem. The pilot assembly includes one or more components configured to inject fuel into a combustor of the engine. The fuel injector also includes a substantially tubular premix barrel extending along the longitudinal axis from a first end to a second end. The premix barrel is circumferentially disposed about the stem and configured to couple with the combustor at the second end. The fuel injector also includes an annular premix duct formed between the premix barrel and the stem. The premix duct includes an air inlet port at the first end, and a plurality of first orifices located downstream of the air inlet port. The first orifices are configured to inject fuel from the fuel tube into the premix duct.

Abstract: The dual-fuel nozzle for a gas turbine and combustor includes a liquid fuel nozzle surrounded by a gas fuel nozzle. A converging sleeve surrounds the converging outer wall of the combined liquid fuel and gaseous nozzle to form a duct of decreasing cross-sectional area in a downstream direction whereby air flow through the duct accelerates toward the conical droplet spray pattern emerging from the liquid fuel nozzle. An inside swirler is located upstream of the liquid fuel tip to swirl the air flowing through the duct. An outer swirler is provided about the downstream end of the sleeve, likewise to swirl air. The accelerated swirling air flow through the duct and outer swirling air flow preclude impingement of oil spray droplets onto metal surfaces of the nozzle and hence prevent carbon deposition thereon which would otherwise be deleterious to the liquid fuel and gaseous nozzles.

Abstract: The dual-fuel nozzle includes a liquid fuel nozzle surrounded by an air/gas premixing cup. The cup has a base comprised of swirler vanes surrounding the outer tube of the liquid fuel nozzle. The tip of the liquid fuel nozzle extends to adjacent the open end of the premixing cup opposite the swirler vanes. The interior surface and outer surface of the premix cup and the tip of the liquid fuel nozzle, respectively, at the outer end of the cup are contoured, i.e., tapered complementarily inwardly to avoid recirculation of air in the annulus between the liquid fuel nozzle and the cup. Air recirculation is also prevented, thereby inhibiting flame holding adjacent the base of the cup by providing a smooth transition for air flow through the openings of the swirler at the base of the cup and into the annulus.