Abstract: A combustor comprises an outer combustor casing defining a plurality of circumferentially adjoining combustion chambers. Each combustion chamber comprises a dome at an upstream end and an outlet at a downstream end. A plurality of pre-mixers are joined to the combustor dome of each respective combustion chamber. The pre-mixers comprise a duct having an inlet at one end for receiving compressed air, an outlet at an opposite end disposed in flow communication with the combustion chamber and a swirler disposed in the duct adjacent the duct inlet for swirling air channeled therethrough. A fuel injector is provided for injecting fuel into the pre-mixer ducts and for mixing with the air in the ducts for flow into the combustion chamber to generate a combustion flame at the duct outlets.

Abstract: A combustor comprises an outer combustor casing defining a plurality of circumferentially adjoining combustion chambers. Each combustion chamber comprises a dome at an upstream end and an outlet at a downstream end. A plurality of pre-mixers are joined to the combustor dome of each respective combustion chamber. The pre-mixers comprise a duct having an inlet at one end for receiving compressed air, an outlet at an opposite end disposed in flow communication with the combustion chamber and a swirler disposed in the duct adjacent the duct inlet for swirling air channeled therethrough. A fuel injector is provided for injecting fuel into the pre-mixer ducts and for mixing with the air in the ducts for flow into the combustion chamber to generate a combustion flame at the duct outlets.

Abstract: In a gas turbine having a plurality of combustors, each having an annular array of outer fuel nozzles arranged about a center axis, an improved construction is provided wherein each combustor has a center nozzle located on the center axis. Various methods of operating the improved combustor are also disclosed.

Abstract: In a gas turbine having a plurality of combustors, each having an annular array of outer fuel nozzles arranged about a center fuel nozzle. A method for operating the combustors wherein the annular array is supplied with fuel from a diffusion manifold and at least one pre-mix manifold, and further wherein the center nozzle is supplied with fuel from a center premix manifold includes the steps of:a) at start-up, supplying some of the annular array nozzles with diffusion fuel;b) at part speed supplying pre-mix fuel to one of the nozzles in the annular array;c) at full speed, part load, transferring the annular array nozzles receiving diffusion fuel to pre-mix fuel;d) as load is increased supplying pre-mix fuel to the center nozzle; and thene) supplying additional pre-mix to all nozzles as load increases.

Abstract: In a gas turbine having a plurality of combustors, each having an annular array of outer fuel nozzles arranged about a center axis, an improved construction is provided wherein each combustor has a center nozzle located on the center axis. Various methods of operating the improved combustor are also disclosed.

Abstract: An improved gas turbine combustor of the type including primary and secondary combustion chambers with a venturi including a throat portion located therebetween; a plurality of primary fuel injection nozzles secured to a combustor cap in an annular array upstream of the primary combustion chamber; and a centerbody including a secondary fuel nozzle, said centerbody extending from said combustor cap to said secondary combustion chamber; the improvement comprising a plurality of tertiary fuel injection nozzles arranged in a circular array about a longitudinal axis of the combustor, at a downstream of said venturi throat portion, for injecting fuel into the secondary combustion chamber.

Abstract: An improved gas turbine combustor of the type including primary and secondary combustion chambers with a venturi including a throat portion located therebetween; a plurality of primary fuel injection nozzles secured to a combustor cap in an annular array upstream of the primary combustion chamber; and a centerbody including a secondary fuel nozzle, said centerbody extending from said combustor cap to said secondary combustion chamber; the improvement comprising a plurality of tertiary fuel injection nozzles arranged in a circular array about a longitudinal axis of the combustor, at a location downstream of said venturi throat portion, for injecting fuel into the secondary combustion chamber.

Abstract: An improved gas turbine combustor is provided which reduces nitric oxide emissions through premixing of the fuel gas and air and feeding the mixture through a venturi, providing an air cooled passage around the venturi, and extending the passage downstream toward the combustion zone to optimize the stability of the combustion and reduce NO.sub.x and CO emissions.

Abstract: Reducing NO.sub.x emission levels from a gas turbine combustor having a premixer section by mixing a small portion of air into the fuel prior to injection into the premixer section. The portion of diverted air is approximately five percent of the total amount of air injected into the premixer section or such that the resulting fuel-air mixture in the fuel line is approximately half fuel and half air. The injection of air into the fuel line, referred to as "head start partial premixing," is effective to reduce the fluctuations and nonuniformities in the fuel concentration levels which increase NO.sub.x output.

Abstract: A dual mode, dual stage low NOx combustor, includes a primary combustion chamber and a secondary combustion chamber separated by a throat region of reduced diameter. Fuel is input into the primary combustors by an annular array of diffusion type nozzles whereas in accordance with the invention, fuel is input into the secondary combustor by a central combination premix and diffusion nozzle. A premix swirler annulus is located upstream of a plurality of fuel distribution tubes of the combined premix and diffusion nozzle.

Abstract: An improved gas turbine combustor is provided which reduces nitric oxide emissions through premixing of the fuel gas and air and feeding the mixture through a venturi, providing an air cooled passage around the venturi, and extending the passage downstream toward the combustion zone to optimize the stability of the combustion and reduce NO.sub.x and CO emissions.

Abstract: It has been found that in a dry low NOx combustor of the type having an upstream combustion chamber and a downstream combustion chamber interconnected by a venturi section, the fuel-air ratio and uniform fuel-air mixing can be improved by providing an annular shield upstream of the venturi region. The shield is impingement cooled through the venturi and provision is made for dumping cooling air farther downsteam in the downstream combustion chamber. With the aforesaid improvements in mind, the upstream combustion chamber is provided with first and second inner liners which are also impringement cooled an which provide combustion air farther upstream into the upstream combustion chamber to further improve fuel-air mixing and to maintain the desired fuel-air ratio.

Abstract: A dual mode, dual stage low NOx combustor, includes a primary combustion chamber and a secondary combustion chamber separated by a throat region of reduced diameter. Fuel is input into the primary combustors by an annular array of diffusion type nozzles whereas in accordance with the invention fuel is input into the secondary combustor by a central combination premix and diffusion nozzle.

Abstract: The control of nitrogen oxides (NOx) is an important feature in the design and operation of gas turbines. It has been found that the production of NOx is affected by the fuel-air ratio within the combustor liner. To this end, an improved combustor liner is proposed which allows the distribution of combustion air and dilution air into the combustion liner in accordance with temperature conditions immediately surrounding the combustor liner. In one embodiment, an apertured ring is rotated in and out of register with dilution air holes in the liner to selectively affect the amount of dilution air and therefore also combustion air into the liner. The ring is driven by a temperature sensitve metals trip wound about the combustor liner. In another embodiment of the invention, the residence time of the combustion reaction is affected by the selection of upstream and or downstream dilution air holes in accordance with the position of the ring holes.

Abstract: A heat exchanger system exhibits an improved coefficient of heat transfer over a conventional convection heat exchanger while maintaining the beneficial high temperature driving force of conventional convection heat exchanger. A plurality of heat extraction means are provided in heat flow communication with a plurality of shallow beds of particulate matter, which beds are fluidized by a heat-laden gas stream.A method for extracting heat from a heat-laden gas stream is also disclosed.

Abstract: A means for cleaning a gas distributor of a fluidized bed comprises a pneumatic motion imparting means, such as a gas jet, for imparting motion to a cleaning medium, such that the medium strikes the gas distributor from the gas input side thereof with sufficient momentum to chip or scrape off at least a portion of any particulate matter adhering to a surface thereof. The gas jet preferably operates intermittently to maintain heat exchange efficiency and preferably is allowed to nutate to increase the area cleaned. In the method for cleaning the gas distributor, the cleaning medium is larger than the gas passages of the gas distributor. In another configuration, the cleaning medium is of the same material as the fluidized material and is smaller than the gas passages of the gas distributor, thus allowing at least a portion of the cleaning medium to pass through the distributor. The cleaning medium is replenished from the fluidized material.

Abstract: A heat exchanger system exhibits an improved coefficient of heat transfer over a conventional convection heat exchanger while maintaining the beneficial high temperature driving force of conventional convection heat exchanger. A plurality of heat extraction means are provided in heat flow communication with a plurality of shallow beds of particulate matter, which beds are fluidized by a heat-laden gas stream.A method for extracting heat from a heat-laden gas stream is also disclosed.

Abstract: A gas distributor for fluidizing a bed of particulate matter which provides for minimum dissipation of particle energy from a particulate-laden gas stream on a distributor surface is disclosed. The gas distributor allows the particulate-laden gas stream to contact the surfaces of the distributor at about 90.degree. or 0.degree. which are angles of impact for low erosion. Opposing particulate-laden gas streams are made to contact each other which removes particle kinetic energy while minimizing erosion before fluidizing the bed of particulate matter.A method to minimize erosion of a gas distributor for fluidizing a bed of particulate matter from a particulate-laden gas stream is also disclosed.