Abstract: The present invention discloses an apparatus and method for reducing the carbon monoxide emissions emitted by a pilot injector of a gas turbine combustor. Multiple embodiments of a means for establishing a recirculation zone are disclosed whereby a portion of the fuel and air mixture from the pilot injector recirculates and a flame is held, thereby increasing the local reaction temperature at the desired location and lowering carbon monoxide emissions.

Abstract: A seal extending between adjacent slots of a gas turbine engine is disclosed. The seal comprises a plurality of generally planar members fixed together along a central axis. The outer member further comprises rounded ends that encompass the second and plurality of third generally planar members. The seal disclosed herein improves sealing capability by providing a more compliant seal over the prior art while reducing the mechanical loads experienced along the seal weld joint, thereby improving seal durability.

Abstract: A gas turbine combustion liner is disclosed having an alternate interface region between it and a transition duct where the cooling effectiveness and heat transfer along the aft end of the combustion liner is improved, resulting in extended component life. The region of the combustion liner proximate its second end comprises a plurality of first feed holes, a plurality of spring seals that seal against a transition duct, a cooling ring having a plurality of second feed holes, that with the first feed holes pass a cooling fluid into an annulus formed between the cooling ring and combustion liner. The cooling fluid passes over a means for augmenting the heat transfer proximate the combustion liner second end, wherein the heat transfer augmentation preferably comprises a plurality of raised ridges that increases the surface area of the outer liner wall to turbulate the cooling fluid and maximize the cooling effectiveness.

Abstract: A fuel nozzle and gas turbine combustor capable of operating on multiple fuels with reduced carbon build-up to the fuel nozzle and adjacent combustor components is disclosed. The fuel nozzle incorporates a reconfigured gas fuel assembly and mixing tube to eliminate known areas of recirculation. Furthermore, the liquid fuel assembly includes reconfigured spray characteristics to further reduce droplet interaction with the mixing tube.

Abstract: An end cover for a gas turbine combustor that eliminates the use of braze joints within the plate portion of the end cover is disclosed. The end cover comprises a plate and a plurality of fluid inlets with the fluid inlets directing fluids to first and second manifolds machined into the end cover. The fluids within the end cover are kept separate proximate each of the plurality of first openings by a wall that is integrally formed from a portion of the end cover plate.

Abstract: A method of operating a gas turbine combustion system having reduced emissions and improved flame stability at multiple load conditions is disclosed. The improved combustion system accomplishes this through complete premixing, a plurality of fuel injector locations, combustor geometry, and precise three dimensional staging between fuel injectors. Axial, radial, and circumferential fuel staging is utilized including fuel injection proximate air swirlers. Furthermore, strong recirculation zones are established proximate the introduction of fuel and air premixture from different stages to the combustion zone. Fuel injection staging sequences are disclosed that create the conditions necessary to provide stable combustion and reduced emissions at multiple load conditions.

Abstract: The present invention seeks to provide a turbine blade with increased creep capability for both uncooled and cooled turbine blades while generally maintaining operating stress levels at an interface region between the turbine blade and a turbine disk. A turbine blade is disclosed having an attachment, a neck, a platform, and an airfoil. Extending radially outward from the attachment, through the neck, and terminating radially inward of the platform is a plurality of first cavities. The turbine blade in accordance with the preferred embodiment of the present invention is cast from a high density nickel base alloy with high temperature capability and improved creep capability. A plurality of first cavities are placed in the attachment and neck region to reduce excess weight of the turbine blade due to the higher density, greater creep capable alloy. Reducing the weight of the blade in this region provides increased creep capability in the turbine blade airfoil while maintaining operating stress levels.

Abstract: A gas turbine combustion system having reduced emissions and improved flame stability at multiple load conditions is disclosed. The improved combustion system accomplishes this through complete premixing, a plurality of fuel injector locations, combustor geometry, and precise three dimensional staging between fuel injectors. Axial, radial, and circumferential fuel staging is utilized including fuel injection proximate air swirlers. Furthermore, strong recirculation zones are established proximate the introduction of fuel and air premixture from different stages to the combustion zone. The combination of the strong recirculation zones, efficient premixing, and staged fuel flow thereby provide the opportunity to produce low emissions combustion at various load conditions.

Abstract: A turbine blade including an airfoil having a profile in accordance with Table 1 is disclosed. The turbine blade has a plurality of cooling passages extending radially outward through the airfoil. The aerodynamic profile of the airfoil has been reconfigured to reduce airfoil stress for a given operating temperature, thereby resulting in increased creep rupture life of the airfoil.

Abstract: A dual fuel premix nozzle and method of operation for use in a gas turbine combustor is disclosed. The dual fuel premix nozzle utilizes a fin assembly comprising a plurality of radially extending fins for injection of gas fuel and compressed air in order to provide a more uniform injection pattern and homogeneous mixture. The premix fuel nozzle includes a plurality of coaxial passages, which provide gaseous fuel and compressed air to the fin assembly. When in liquid fuel operation, the gas circuits are purged with compressed air and liquid fuel and water pass through coaxial passages to the tip of the dual fuel premix fuel nozzle, where they inject liquid fuel and water into the secondary combustion chamber. An alternate embodiment includes an additional gas fuel injection region located along a conically tapered portion of the premixed fuel nozzle, downstream of the fin assembly.

Abstract: A crossfire tube assembly is provided having an increased resistance to wear and oxidation. This increased resistance is provided by the application of coatings to the mating surfaces between the crossfire tube and crossfire tube clip. In the preferred embodiment, a physical vapor deposition (PVD) Titanium Aluminum Nitride coating is applied to the outer walls of the crossfire tubes which is used in combination with an air plasma spray (APS) Aluminum Bronze coating applied to the crossfire tube clip open end that mates with the crossfire tubes. The coating combination serves to protect the components from frictional wear and extend their life. In an alternate embodiment, the crossfire tubes also contain a plurality of air purge holes that provide a layer of cooling air along the crossfire tube inner wall.

Abstract: An attachment and sealing system for securing a combustor cap assembly to a combustion chamber, while providing effective cooling to the combustor cap assembly aft end, is disclosed. The combustor cap assembly is secured within a combustion chamber by a plurality of pins such that the aft end region of the combustor cap assembly is cooled by a fluid medium that is injected through a plurality of first holes in the combustion chamber wall. A generally annular seal, which encompasses the combustor cap assembly, has a plurality of raised ridges, which are in sealing contact with the combustion chamber wall. Multiple embodiments are disclosed regarding the length of the generally annular seal and position and orientation of the plurality of first cooling holes in the combustion chamber wall.

Abstract: A wear cover for use on a gas turbine transition duct support bracket is disclosed. The wear cover, which is manufactured from a single piece of sheet metal, does not require complex manufacturing processes or tools, thereby reducing component cost. The wear cover comprises first and second leg portions substantially parallel to each other and each generally perpendicular to a third leg portion. Each of the leg portions serve to protect a surface of a support bracket finger from excessive wear associated with frictional contact with mounting blocks of a transition duct. The wear cover is designed to slip onto a support bracket finger through a first opening and is fixed to the finger by a means such as welding.

Abstract: A premix fuel nozzle and method of operation for use in a gas turbine combustor is disclosed. The premix fuel nozzle utilizes a fin assembly comprising a plurality of radially extending fins for injection of fuel and compressed air in order to provide a more uniform injection pattern. The fuel and compressed air mixes upstream of the combustion chamber and flows into the combustion chamber as a homogeneous mixture. The premix fuel nozzle includes a plurality of coaxial passages, which provide fuel and compressed air to the fin assembly, as well as compressed air to cool the nozzle cap assembly. An alternate embodiment includes an additional fuel injection region located along a conically tapered portion of the premixed fuel nozzle, downstream of the fin assembly. A second alternate embodiment is disclosed which reconfigures the injector assembly and fuel injection locations to minimize flow blockage issues at the injector assembly.

Abstract: A pilot fuel nozzle configuration for use in a combustor is disclosed having a natural frequency outside the range of the operating frequencies of a gas turbine engine. Multiple embodiments are disclosed for the improved pilot fuel nozzle including configurations for newly manufactured nozzles, repair to existing pilot nozzles, as well as multiple natural frequency levels for the improved pilot fuel nozzle. The pilot fuel nozzle comprises an elongated housing, first and second flanges, and a nozzle tip, with the first flange fixed to the elongated housing at a first end and the nozzle tip fixed to the second end, opposite of the first end. The second flange is fixed along the elongated housing and is used for attaching the pilot fuel nozzle to a combustor. The present invention incorporates an increased wall thickness along at least a mid-span portion of the pilot nozzle to increase the stiffness and change the natural frequency.

Abstract: A method for providing a gas turbine engine and a combustor having a more uniform fluid flow is disclosed. For a combustor end cover, individual nozzle flow rates are determined and nozzles positioned on an end cover such that each nozzle injects substantially the same amount of fluid as an adjacent nozzle. As a result, gas temperature variations within the combustor are reduced and combustion dynamics lowered. For a gas turbine engine utilizing a plurality of combustors, individual end cover flow rates are determined and end covers positioned on each combustor relative to the supply inlet of the engine such that each end cover is supplied with a substantially similar flow rate. Other factors including pressure loss and fluid temperature changes are taken into consideration when determining nozzle and end cover positions.

Abstract: A method of operating a gas turbine combustor to achieve overall lower emissions of nitrous oxides by supplying a mixture of natural gas and hydrogen gas to the combustion chamber of the gas turbine in a manner that the localized concentration of hydrogen gas is greater than 0.1% by mass of the mass of the mixture, and less than 20.0% by mass of the mixture prior to combusting the mixture in the combustion chamber.

Abstract: A two-stage gas turbine combustor is disclosed that incorporates an improved assembly and disassembly methodology that results in improved inspection and repair techniques. The combustor includes an upper liner, lower liner, cap assembly, and a venturi assembly that directs cooling air into the combustion chamber for use in the combustion process, wherein a venturi assembly is inserted within an upper liner and an upper liner is then inserted in a lower liner. The venturi assembly, upper liner, and lower liner are fixed together with a plurality of easily removable retaining pins. The improved assembly allows for easier inspection and repair of the upper liner, lower liner, and venturi assembly.

Abstract: An improved secondary fuel distribution system having a readily adjustable premix pilot nozzle for use in a gas turbine combustor is disclosed. The secondary fuel nozzle assembly has a premix fuel nozzle comprising an annular tubular manifold and a premix pilot nozzle. Multiple embodiments of premix pilot nozzles are disclosed that have a fuel flow rate that can be controlled and adjusted as required, including a plate and feed hole combination, a pressfit premix pilot nozzle, and a premix pilot nozzle that is threaded into the secondary fuel nozzle assembly.

Abstract: A fully premixed secondary fuel nozzle assembly for use in a gas turbine combustor having multiple combustion chambers, in which the products of the premixed secondary fuel nozzle assembly are injected into the second combustion chamber for supporting a pilot flame and flame transfer between combustion chambers, is disclosed. The improvement includes the elimination of the pilot fuel circuit, which previously served to establish flame in the second combustion chamber. The secondary fuel nozzle assembly includes at least one first injector extending radially outward from the fuel nozzle body for injecting all fuel from the fuel nozzle to mix with compressed air prior to combustion. The first injector can include a plurality of tubes or an annular manifold circumferentially disposed about the nozzle body. Compressed air is drawn into the nozzle body and passes through holes in an injector plate at the tip region to provide cooling.