Abstract: The present invention relates generally to a low emission can-annular combustion system for an industrial gas turbine engine to satisfy increasingly stringent environmental requirements. The combustion system of the present invention employs a dual mode combustion technique to meet engine operability requirements and high power emission targets without the use of combustor diluent injection or post combustor exhaust treatment. A lean premix combustion mode is utilized to minimize primary zone combustion temperatures and limit the oxide of nitrogen production during high power engine operation. A pilot-starting auxiliary fueling system is utilized to augment the main premix fueling system. The lean premix combustion mode is enabled by a lean premix dome having a fixed axial swirler with radial fuel pathways connecting to a circumferential main fuel manifold for distributing the fuel more uniformly across the flow path.

Abstract: In a combustion chamber (100) which is designed as an annular combustion chamber and a mixing essentially comprises a primary zone (1), a mixing section (2) arranged downstream and an adjoining secondary stage (3), vortex generators (200) are fixed inside the mixing section (2), which vortex generators (200) serve to form vortices. Both the mixing section (2) and the vortex generators (200) are provided with passage openings through which mixing air (8) flows into the interior of the mixing section (2) and mixes there with the main flow (4). The quantity of the intermixed mixing air (8) is variable; it can have a supercritical or subcritical blow-out rate relative to the main flow (4), and in this connection at least film cooling of the duct walls (5, 6) and of the vortex generators (200) takes place even at subcritical blow-out rate.

Abstract: This invention pertains to small air breathing gas turbine engines (1). Engines of the invention employ improved combustion systems, including improved fuel injection systems and improved combustor design. These improvements enable the engine to idle at speeds as low as one-tenth the maximum operating speed of the engine, which gives the engine an increased range of operating speeds. The improved designs generally provide for pre-mix assemblies intimate with the fuel injectors, a typically flame-free primary "A" mixing zone in the combustion chamber, and a primary "B" combustion zone, in addition to the secondary combustion zone and the dilution zone. In preferred embodiments, the bearing assembly is located between the compressor and the turbine wheel. A cooling cavity is provided between the turbine wheel and the bearing assembly, thus protecting the bearings from the turbine heat.

Abstract: An inverse combined steam-gas turbine cycle is disclosed. In the steam cycle, a fuel having a high nitrogen content such as coal or heavy fuel oil is burned in a boiler to raise steam to power a steam turbine. In the gas turbine cycle, a hydrocarbon fuel such as natural gas is burned in a gas combustor to power a gas turbine. The compressed exhaust gas (40. 42) from the steam cycle combustion is introduced into the gas combustor, where nitrogen oxides (NO.sub.x) in the exhaust gas may be reduced through reactions with the hydrocarbon fuel.

Abstract: A staged combustion apparatus for a gas turbine to lower the concentration of NO.sub.x and CO in the exhaust gases. Combustion occurs in a first and second stage, the first stage being sub-stoichiometric combustion and the second stage being above-stoichiometric combustion. Cyclonic combustion occurs in one of the first and second combustion stages and a swirling pattern of combustion occurs in the other of the combustion stages. Steam injection is provided to further lower the concentration of NO.sub.x in the exhaust emissions from the gas turbine.

Abstract: A solid fuel, pressurized fluidized bed combustion system for a gas turbine engine includes a carbonizer outside of the engine for gasifying coal to a low Btu fuel gas in a first fraction of compressor discharge, a pressurized fluidized bed outside of the engine for combusting the char residue from the carbonizer in a second fraction of compressor discharge to produce low temperature vitiated air, and a fuel-rich, fuel-lean staged topping combustor inside the engine in a compressed air plenum thereof. Diversion of less than 100% of compressor discharge outside the engine minimizes the expense of fabricating and maintaining conduits for transferring high pressure and high temperature gas and incorporation of the topping combustor in the compressed air plenum of the engine minimizes the expense of modifying otherwise conventional gas turbine engines for solid fuel, pressurized fluidized bed combustion.

Abstract: A method of combusting a hydrocarbon fuel includes mixing the fuel with a first air stream to form a fuel/air mixture having an equivalence ratio of greater than 1 and partially oxidizing the fuel by contacting it with an oxidation catalyst to generate a heat of reaction and a partial oxidation product stream. The partial oxidation product stream is mixed with a second air stream and completely combusted in a main combustor at a condition at which appreciable quantities of thermal NO.sub.x are not formed to generate an effluent gas stream, thereby generating an effluent gas stream containing decreased amounts of thermal and prompt NO.sub.x. A system for combusting a hydrocarbon fuel includes, in combination, means for mixing the fuel with a first air stream, a catalytic oxidation stage containing an oxidation catalyst, means for mixing the partial oxidation product stream with a second air stream, and a main combustor capable of completely combusting the partial oxidation product stream.

Abstract: The present invention relates to a combustion chamber having a counter-flow arrangement in which a first chamber portion mixes the fuel with the primary oxidizer, which mixture is ignited and burned in the first chamber portion. The exhaust gases from the first chamber portion pass into a second chamber portion in which dilution oxidizer air is added to the burned gases. The orientations of the first chamber portion and the second chamber portion are such that the gases pass through the chamber portions in substantially opposite directions, in a counter-flow arrangement. The first chamber portion in which the combustion takes place, provides only primary oxidizer to the fuel mixture, there being no further communication between the interior of the first chamber portion and the oxidizer air supply. This prevents the leaning of the fuel/air mixture in order to reduce the emissions of nitrogen oxide. The mixing of secondary oxidizer air with the exhaust gases takes place solely in the second chamber portion.

Abstract: A method of combusting an endothermic fuel with staged rich/lean combustion includes transferring thermal energy from a heat source, such as the wall of a rich combustor, to an endothermic fuel decomposition catalyst to cool the heat source and heat the fuel and catalyst to a temperature sufficient to endothermically decompose an endothermic fuel. The catalyst is contacted with the fuel to cause the fuel to decompose into a reaction product stream. The reaction product stream is mixed with a first air stream to form a first fuel/air mixture having an equivalence ratio greater than 1 and the first fuel/air mixture is combusted in a rich combustion stage to produce a combustion product stream. The combustion product stream is mixed with a second air stream to form a second fuel/air mixture having an equivalence ratio less than 1 and the second fuel/air mixture is combusted in a lean combustion stage to produce an exhaust gas stream containing decreased amounts of NO.sub.x.

Abstract: Two-stage combustion of nitrogen-containing gas with low NO.sub.x emissions, in a combustion chamber, wherein first, pre-combustion is performed in a primary stage at an air number of approximately .lambda.=0.6 to 0.9 and subsequently post-combustion is performed in a secondary stage at an air number of approximately .lambda.=1.3 to 2, characterized in that in the primary stage, an inert substance is supplied via a multiplicity of openings in the walls of the primary stage, which substance cools the walls and keeps the combustion zone remote from the walls.

Abstract: A circumferentially stirred variable residence time vortex combustor including a primary combustion chamber for containing an annular combustion vortex and a first plurality of louvres peripherally disposed about the primary combuston chamber and longitudinally distributed along its primary axis, the louvres inclined to impel air circumferentially about the primary axis within the primary combustion chamber, to cool its interior surfaces, to impel air inwardly to assist in driving the annular combustion vortex in a helical path, and to feed combustion in the primary combustion chamber. The vortex combustor further includes a second annular combustion chamber and a narrow annular waist region interconnecting the output of the primary combustion chamber with the second annular combustion chamber for passing only lower density particles and trapping higher density particles for substantial combustion in the annular combustion vortex of the primary annular combustion chamber.

Abstract: Two-stage combustion of nitrogen-containing gas with low NO.sub.x emissions, in a combustion chamber, wherein first, pre-combustion is performed in a primary stage at an air number of approximately .lambda.=0.6 to 0.9 and subsequently post-combustion is performed in a secondary stage at an air number of approximately .lambda.=1.3 to 2, characterized in that in the primary stage, an inert substance is supplied via a multiplicity of openings in the walls of the primary stage, which substance cools the walls and keeps the combustion zone remote from the walls.

Abstract: A circumferentially stirred variable residence time vortex slinger combuster, includes a primary combustion chamber for containing an annular combustion vortex and a first group of louvres peripherally disposed about the primary combustion chamber and distributed along its primary axis. The louvres are inclined to impel air circumferentially about the primary axis within the primary combustion chamber to cool its interior surfaces, to impel air inwardly to assist in driving the annular combustor vortex in a helical path, and to feed combustion in the primary combustion chamber. The slinger combustor further includes a second annular combustion chamber and a narrow annular waist region interconnecting the output of the primary combustion chamber with the second annular combustion chamber. The waist region passes only lower density particles and traps higher density particles for substantial combustion in the annular combustion vortex of the primary annular combustion chamber.

Abstract: An external combustion system for a stationary gas turbine engine includes a rich zone combustor, a water or steam quench stage, a lean zone combustor and a dilution stage. Fuel such as natural gas or liquid hydrocarbon, which forms no ash or slag, burns in a primary air supply in the rich zone combustor at an equivalence ratio exceeding 1 which inhibits rapid formation of of oxides of nitrogen. The effluent from the rich zone combustor is a stream of combustible gas including carbon monoxide and hydrogen. The combustible gas stream is quenched in the quench stage and mixed with a secondary supply of compressed air in the lean zone combustor. The combustible gas ignites spontaneously in the lean zone combustor and burns at an equivalence ratio of less than 1 and at a temperature below the range characterized by rapid formation of oxides of nitrogen.

Abstract: A method for operating a rocket engine by injecting fuel and oxidizer into an elongated combustion chamber in two flows, a core flow where the fuel and oxidizer are intimately mixed and immediately combusted and a peripheral curtain flow which surrounds the core flow and which is in contact with the combustion chamber wall to cool it and limit the heat transfer from the wall to the injector to prevent vapor locks in the injector. To prevent decomposed or partially combusted propellant products from chemically reacting with the chamber wall no mixing of fuel and oxidizer takes place in the curtain flow. The curtain flow is deflected radially inward into the core flow, before decomposed or partially combusted products can come into contact with the wall, into the core flow to fully combust the curtain flow out of contact with the wall. The rocket engine is defined by serially arranged first and second combustion chambers and an injector constructed to form the core and curtain flows.

Abstract: A method for burning a fuel, containing chemically bound nitrogen, in a two-stage, rich-lean combustion process, including; introducing the fuel and at least one stream of primary air into a primary combustion region at a fuel-air ratio above the stoichiometric ratio and in a manner to intimately mix the fuel and air and establish a stabilized flame adjacent the upstream end of the primary combustion region, maintaining the flame in the primary combustion region for a period of time sufficient to produce a combustion product mixture containing less than a predetermined amount of NO.sub.x pollutants and abruptly terminating the primary combustion region while introducing at least one stream of secondary air into the secondary region in an amount sufficient to reduce the overall fuel-air ratio below the stoichiometric ratio and in a manner to prevent backflow of the secondary air into the primary combustion region.

Abstract: A staged low NO.sub.x gas turbine combustor includes a refractory fibrous thermally insulatively lined primary combustion chamber, operating fuel-rich, and exhausting through a throat into a metallic secondary combustion chamber containing a fuel-lean secondary combustion zone in which combustion is completed. A radiation cooling zone is provided intermediate the throat and secondary combustion zone for cooling of the primary combustion products before quick quench in the secondary combustion zone. The fibrous lining of the primary combustion chamber is densified at its interior surface with a refractory such as zirconia or silicon carbide to inhibit flame erosion. The liner is wrapped with a supportive compliant blanket of fibrous refractory insulation. Air cooling of the metallic wall of the secondary chamber surrounding the radiation cooling zone is intensified relative to the remainder of the secondary combustion chamber.

Abstract: A dilution air dispensing apparatus for a double dome combustor with dilution air dispensing holes that are staggered on the opposite walls of the centerbody. The wakes on the downstream side of the jets provide avenues of access for the deflected combustion gases to continue their travel across the combustor and into the regions downstream of the opposite domes. The gases then mix with the remaining undeflected gases from the domes and with the spent dilution air before reaching a combustor exit plane.

Abstract: A method for burning a fuel, containing chemically bound nitrogen, in a two-stage, rich-lean combustion process, including: introducing the fuel and at least one stream of primary air into a primary combustion region at a fuel-air ratio above the stoichiometric ratio and in a manner to intimately mix the fuel and air and establish a stabilized flame adjacent the upstream end of the primary combustion region, maintaining the flame in the primary combustion region for a period of time sufficient to produce a combustion product mixture containing less than a predetermined amount of NO.sub.x pollutants and abruptly terminating the primary combustion region while introducing at least one stream of secondary air into the secondary region in an amount sufficient to reduce the overall fuel-air ratio below the stoichiometric ratio and in a manner to prevent backflow of the secondary air into the primary combustion region.

Abstract: Combustion apparatus for a gas turbine engine comprises a burner which is so configured and located within a combustion chamber so as to urge fuel and air mixture ejected therefrom into a fuel rich toroidal vortex in an upstream first combustion zone of the combustion chamber. Unburnt fuel from the first combustion zone is mixed with additional air in a second fuel weak combustion zone downstream of the first zone. Adjustment of the air to fuel ratios in the two combustion zones results in the reduction of smoke and oxides of nitrogen reduction.

Abstract: A pulse combustion device having a mixing chamber arranged to be supplied with primary air and gaseous fuel, and a combustion chamber which is supplied with a mixture of gaseous fuel and air from the mixing chamber to take place pulse combustion of the mixture therein. The pulse combustion device includes an air intake system which is composed of a primary air intake system for adjusting an amount of primary air supplied into the mixing chamber to create a rich mixture of gaseous fuel and primary air in the mixing chamber, and a secondary air intake system for supplying secondary air into the combustion chamber and for adjusting an amount of the secondary air to be mixed with the rich mixture in the combustion chamber.

Abstract: A catalytic combustor unit for a stationary combustion turbine includes a substrate composed of a plurality of intersecting walls defining a series of generally parallel passages aligned in rows and columns, open at their opposite ends and exposed to a heated flow of fuel and air mixture therethrough. The walls have sections which border and define the respective passages. Each wall section is in common with two adjacent passages and has a pair of oppositely-facing surface regions, one of which is exposed to one of the two adjacent passages and the other exposed to the other of the two adjacent passages. A catalyst coating is applied on selected ones of the wall surface regions exposed to certain ones of the passages, whereas selected others of the wall surfaces exposed to certain others of the passages are free of the catalyst coating.

Abstract: A domestic or industrial fuel spray combustion device which includes a cylinder-shaped swirl chamber into which air streams are introduced; a fuel injection atomizer for spraying fuel to the swirl chamber; an ignition plug; a first combustion cylinder connected through a choke to the swirl chamber, the first combustion cylinder being coaxial with the swirl chamber; and being larger than an equal to the swirl chamber in diameter and a second combustion cylinder connected through a choke to the first combustion cylinder, the second combustion cylinder being coaxial with the first combustion chamber and being equal to or smaller than the first combustion cylinder in diameter. This structure provides a compact combustion device which enables stable combustion even with a small amount of fuel.

Abstract: A combustor capable of reducing the noxious emissions such as fuel bound and thermal nitrogen oxide products, during combustion of high nitrogen bearing and high aromatic content fuels is disclosed. The combustor includes a plurality of substantially concentric pipes defining annular passages with annular divergent nozzles. The divergent nozzles may be formed by rings having a venturi shaped axial section to facilitate fast mixing of axially supplied air between adjacent annular passages. The longitudinal spacing between at least two adjacent nozzles defines first and second divergent cavities. A fuel rich torodial vortex is formed in proximity to a central fuel jet in the first cavity and advantageously converts fuel bound nitrogen to N.sub.2. A fuel lean torodial vortex formed in the second cavity mixes hot combustion products with additional gaseous reactant to complete the combustion while avoiding locally high temperatures, and thus thermal NOx formation.

Abstract: The externally vaporizing system of the present invention incorporates an auxiliary burner which is supplied with compressor discharge air at a rate which is regulated to the main fuel flow rate. The auxiliary burner is operated at approximately stoichiometric fuel-air ratio, in order to provide very-hot, nearly-inert gases for vaporizing the main fuel supply. The main fuel is sprayed in the auxiliary burner exit gas stream where rapid mixing and evaporation occur. The resulting vaporized fuel/inert gas mixture (at about 800.degree. F., preferably) is then ducted and distributed to the individual main combustor fuel injectors where it is injected into the premixing ducts.

Abstract: An object of the invention is to cool a rich burn combustor without extracting excessive amounts of heat and to use the extracted heat. In accordance with the invention, a combustor (10) having a primary combustor (12) and a secondary combustor (13) with a throat (20) between them is provided with a jacket including a wall (27) radially outwardly of a wall (14) of the primary combustor (12). Steam is injected into a manifold (33) at the throat end of combustor (12) and flows in a plurality of spiral paths through the space between walls (14) and (27) to an outlet manifold (32) at the other end of combustor (12) becoming superheated. The superheated steam is employed to drive a stream utilization device. The spiral steam flow paths are established by barriers (38) wound in spiral fashion on the outside of wall (14) of the combustor (12). Another object is to minimize stress on the wall (14) of the primary combustor (12).

Abstract: A low-NO.sub.x combustor is provided with a rich, primary burn zone and a lean, secondary burn zone. NO.sub.x formation is inhibited in the rich burn zone by an oxygen deficiency and in the lean burn zone by a low combustion reaction temperature.

Abstract: In a low NO.sub.x stage combustor, the hot fuel rich combustion gases exit the primary combustion chamber through a constriction including a throat portion and pass into a secondary combustion chamber wherein burning is completed by injection of secondary air such as the exhaust from a turbine. Swirl is imparted to the primary gas stream in the primary combustion chamber so as to cause the primary gas stream to fill the entire primary combustion chamber and for increasing the residence time within the primary chamber for reducing fuel NO.sub.x emissions. Swirl suppression means are employed in the throat of the flow constrictor, between the primary and secondary combustion chambers, for suppressing swirl in the outermost regions of the primary gas stream so as to reduce turbulent mixing with the injected, secondary air thereby reducing the peak flame temperature in the secondary combustion chamber and for reducing thermal NO.sub.x emissions.

Abstract: A method for burning a fuel, containing chemically bound nitrogen, in a two-stage, rich-lean combustion process, including; introducing the fuel and at least one stream of primary air into a primary combustion region at a fuel-air ratio above the stoichiometric ratio and in a manner to intimately mix the fuel and air and establish a stabilized flame adjacent the upstream end of the primary combustion region, maintaining the flame in the primary combustion region for a period of time sufficient to produce a combustion product mixture containing less than a predetermined amount of NO.sub.x pollutants and abruptly terminating the primary combustion region while introducing at least one stream of secondary air into the secondary region in an amount sufficient to reduce the overall fuel-air ratio below the stoichiometric ratio and in a manner to prevent backflow of the secondary air into the primary combustion region.

Abstract: A variable residence time vortex combustor including a primary combustion chamber for containing a combustion vortex, and a plurality of louvres peripherally disposed about the primary combustion chamber and longitudinally distributed along its primary axis. The louvres are inclined to impel air about the primary combustion chamber to cool its interior surfaces and to impel air inwardly to assist in driving the combustion vortex in a first rotational direction and to feed combustion in the primary combustion chamber. The vortex combustor also includes a second combustion chamber having a secondary zone and a narrowed waist region in the primary combustion chamber interconnecting the output of the primary combustion chamber with the secondary zone for passing only lower density particles and trapping higher density particles in the combustion vortex in the primary combustion chamber for substantial combustion.

Abstract: A combustor having an annular first stage, a generally cylindrically-shaped second stage, and an annular conduit communicably connecting the first and second stages. The conduit has a relatively small annular height and a large number of quench holes in the walls thereof such that quench air injected into the conduit through the quench holes will mix rapidly with, or quench, the combustion gases flowing through the conduit. The rapid quenching reduces the amount of NO.sub.x produced in the combustor.

Abstract: A combustor for a gas turbine engine including a two-stage burner having first and second combustion and exhaust sections and a burner casing coaxially surrounding the burner to define an annular conduit for reverse flow of inlet air. The burner includes a fuel injector at the upstream end thereof, primary inlet ports introducing 18% of inlet air into the first combustion section, first cooling ports introducing 12% of inlet air into the first combustion section for generating a swirling cooling flow which mixes with primary air after cooling the upstream end of the first combustion section, secondary inlet ports introducing 18% of inlet air into second stage combustion section, second cooling ports introducing 8% of inlet air into the second combustion section to generate a swirling flow which mixes with primary air after cooling the upstream end of the second combustion section, and dilution ports introducing 44% of inlet air into the exhaust section to cool the exhaust gas.

Abstract: A combustor for generating a hot gas stream by the combustion of fuel in a pressurized airstream is disclosed including a generally toroidal-shaped combustion chamber of relatively short axial length, an annular orifice providing for the entry of a main airstream into the combustion chamber and a premixing chamber for generating and directing a vapor phase air-fuel premixture into the entering main airstream to form a combustible mixture for burning in the combustion chamber. In a preferred form, the mixture burns along a generally toroidal-helical gas flow path. The combustor is particularly suited for use in a gas turbine engine.

Abstract: A combustor for generating a hot gas stream by the combustion of fuel in a pressurized airstream is disclosed including a generally toroidal-shaped combustion chamber of relatively short axial length, an annular orifice providing for the entry of a main airstream into the combustion chamber and a premixing chamber for generating and directing a vapor phase air-fuel premixture into the entering main airstream to form a combustible mixture for burning in the combustion chamber. In a preferred form, the mixture burns along a generally toroidal-helical gas flow path. The combustor is particularly suited for use in a gas turbine engine.

Abstract: NO.sub.x emissions are reduced in the combustion of fuels by carrying out the combustion in at least four serially connected combustion zones, including at least three fuel-rich zones followed by a fuel-lean zone. In accordance with another aspect of the present invention, SO.sub.x emissions are reduced in the burning of a normally solid fuel, containing significant amounts of SO.sub.x precursors, by adding a sulfur scavenger to the fuel and thereafter burning the fuel in at least four serially connected combustion zones, including at least three fuel-rich zones followed by a last fuel-lean zone, and carrying out the combustion of the fuel in at least four combustion zones.

Abstract: NO.sub.x emissions are reduced in the combustion of a fuel, containing significant amounts of NO.sub.x precursors, by carrying out the combustion in at least three, serially connected combustion zones in open communication with one another, including at least two fuel-rich zones and a last fuel-lean zone and in the presence of a combustion catalyst added to the fuel adjacent the upstream end of the first of the fuel-rich zones. SO.sub.x emissions are also reduced when burning a fuel, containing significant amounts of SO.sub.x precursors, by additionally adding a sulfur scavenger to the fuel adjacent the upstream end of the first fuel-rich zone.

Abstract: A novel method for operating gas turbine combustors while minimizing the formation and discharge of pollutants such as NO.sub.x is described. In one embodiment, the use of more than one catalyst in series is employed to effect fuel oxidation at temperatures below flame temperature, thereby minimizing NO.sub.x formation.In another embodiment, a staged catalytic combustor is employed comprising a two zone combustion chamber involving a noncatalytic zone in which fuel is partially combusted under fuel rich conditions and combustion is completed in the second zone, utilizing catalytic oxidation with excess air to complete the combustion and minimize NO.sub.x formation.Still another embodiment concerns the use of a novel design for the primary combustion zone by which fuel is partially burned with substoichiometric amounts of air and, thereafter, the partially burned primary zone effluent is mixed into the secondary air stream where continued combustion proceeds at a temperature below that needed for NO.sub.

Abstract: In a two stage burner construction in which primary fuel burns in an annulus in a primary combustion zone and secondary fuel is discharged through the primary zone to a secondary zone downstream of the primary zone, vortex generators are used in the passage through which the fuel and air entering the primary zone to enhance the mixing and to improve the toroidal flow in the combustion zone. Other vortex generators are used to improve the mixing of the secondary fuel and air to improve secondary combustion. The vortex generators may be used in conjunction with a trip on the secondary nozzle tube to further enhance primary combustion.

Abstract: Methods of operating combustors to produce lower emissions, particularly lower emissions of nitrogen oxides and CO, including supplying separate streams of air to primary and secondary combustion regions of a combustor, and expanding combustion products when passing same from said primary combustion region to said secondary combustion region. In preferred embodiments, unheated air can be used in said primary combustion region, and/or a second stream of air mixed with said combustion products during said expansion thereof.