Abstract: This invention aims to suppress the occurrence of smoke, for example, during a light load operation of a gas turbine, by adopting an air blast method for a pilot nozzle in a dual fuel combustion low NOx combustor. A gas turbine combustor of the present invention is that in a gas turbine furnished with a dual fuel combustion low NOx combustor having a pilot nozzle capable of injecting a gaseous fuel and a liquid fuel simultaneously or selectively, and a plurality of main nozzles disposed around the pilot nozzle and being capable of injecting a gaseous fuel and a liquid fuel simultaneously or selectively, wherein the pilot nozzle has a gas nozzle portion for injecting the gaseous fuel, and a liquid nozzle portion for injecting the liquid fuel, adopts an air blast method for the liquid nozzle portion, uses combustion air as air for an air blast, and throws the combustion air at a liquid film formed in the liquid nozzle portion to atomize the liquid fuel by use of a velocity difference.

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.