Gas turbine combustor

A gas turbine combustor comprising:

• a generally cylindrical head combustion chamber having a longitudinal axis for effecting therein first stage combustion over a wide load range to produce a gas stream;
• a rear combustion chamber operatively arranged downstream of said head combustion chamber for effecting therein second stage combustion over the wide load range;
• a plurality of nozzles arranged in said head combustion chamber for injecting fuel therein in at least one position downstream from a wall at an upstream end of said head combustion chamber;
• air inlet means arranged in said upstream end wall and in rows around a peripheral portion of said head combustion chamber so as to produce a weak vortex flow upstream of at least some of said nozzles such that the vortex flow includes flow components directed radially from said at least some of said nozzles and reverse flow from said nozzles toward said upstream end wall;
• and
• a plurality of fuel and air supply means annularly arranged at an upstream peripheral wall of said rear combustion chamber for introducing pre-mixed fuel while swirling around the gas stream of said first stage combustion with minimal interference therebetween,
• wherein the nozzles are arranged annularly through said upstream end wall, and alternate nozzles are of different length in the direction of the head combustion chamber longitudinal axis such that one set of nozzles injects fuel downstream of a first row of said air inlet means and a second set of nozzles injects fuel upstream of the first row of said air inlet means.

A gas turbine combustor, comprising:

• an axially elongated inner casing having an upstream side and a downstream side, and end wall provided on the upstream side, said end wall including a plurality of air holes annularly arranged therein, means provided on the downstream side for exhausting a combustion gas to gas turbine blades, said inner casing defining a head combustion chamber on the upstream side and a rear combustion chamber on the downstream side and having a plurality of air holes formed in the peripheral wall defining said head combustion chamber;
• an outer casing disposed with respect to the inner casing so as to form an annular air passage between said inner and outer casing, an end of said outer casing at a distance from said end wall thereby providing an air passage communicating with said annular air passage;
• a hollow frusto-conical tubular member, coaxially disposed in said head combustion chamber of said inner casing so as to project into said head combustion chamber from said end wall, said tubular member having a conical surface defining an annular combustion space in cooperation with said inner casing, said annular combustion space increasing in cross-sectional area from the upstream side toward the downstream side, said tubular member having a plurality of fine cooling air holes on the surface in said head combustion chamber and a closed end on the downstream side;
• a plurality of annularly arranged elongated fuel nozzles secured to said end cover so that said fuel nozzles project into said annular combustion space through said air holes of said end wall so as to form gaps for air passage between said air holes and said fuel nozzles, each of said fuel nozzles having a fuel injection hole at a tip portion thereof, said fuel injection holes being disposed in a vicinity of said air holes formed in said peripheral wall of said head combustion chamber on the upstream side to produce a weak vortex flow upstream of said fuel nozzles;
• a plurality of air inlets annularly arranged on said inner casing for substantially axially introducing air into said rear combustion chamber;
• and
• second stage combustion fuel nozzles arranged annularly around said rear combustion chamber for injecting fuel into said air flows from said fuel inlets so as to provide pre-mixed air and fuel to said rear combustion chamber and configured so as to obtain an annular flame which surrounds and causes no substantial interference with the flame of said head combustion chamber wherein said air holes provided in the peripheral wall of said inner casing are arranged in a plurality of rows axially arranged at an interval therebetween, and an axial position La of said row of air holes on the most upstream side from said end wall is within the range of:
• La=(0.6-1.7).times.Lc,
• where Lc is radial length corresponding to a difference in radius between said inner casing and said tubular member at said end wall, and
• a length Lb of said tubular member from said end wall to the downstream end is within a range of:
• Lb=(2.0-5.20).times.Lf,
• wherein Lf is a position of said fuel injection holes most distant from said end wall.

A gas turbine combustor comprising a head combustion chamber into which fuel and air for a first stage combustion are introduced for combustion therein, and a rear combustion chamber into which pre-mixed fuel and air for a second stage combustion are introduced downstream of said head combustion chamber so as to flow axially while whirling around a longitudinal axis of said combustor, comprising:

• an inner tubular hollow member coaxial with an axis of said head combustion chamber to define an annular combustion space between said head combustion chamber and said tubular member, said tubular member having a front end on a downstream side of said head combustion chamber and a plurality of fine cooling air holes in a peripheral wall thereof;
• a wall positioned at an upstream end of said head combustion chamber and having plurality of air holes formed therein for injecting air in said annular combustion space thereby to form a plurality of vortices, said wall defining an upstream end of said annular combustion space;
• means for producing diffusion combustion around said tubular hollow member during operation of said combustor and vortex mixing between the fuel and air, said means consisting of an inlet means including said air holes and a plurality of fuel nozzles projecting into said annular combustion space a distance sufficient for supplying the fuel for the first stage and opening at a downstream portion of said air holes so that part of the fuel injected by said nozzles is subjected to said vortices for stabilizing the flame formed by first stage combustion in said head combustion chamber upstream of a fuel injection part of one or more of the nozzles, and the remaining part of the fuel produces the diffusion combustion at a downstream side of said vortices;
• and
• a plurality of second stage nozzles provided at a periphery of said rear combustion chamber with air inlet means for pre-mixing of fuel and air and located downstream from the front end of said inner tubular member for injecting premixed fuel and air into said rear combustion chamber.

A gas turbine combustor comprising:

• an outer casing;
• an end cover mounted on one end of said outer casing on the upstream side for closing said one end of said outer casing;
• an elongated inner casing having a small diameter portion defining a head combustion chamber on an upstream side and a large diameter portion greater than that of said small diameter portion and defining a rear combustion chamber on a downstream side, said inner casing being disposed in said outer casing so as to define therebetween an annular air passage communicating with an air compressor;
• combustion air inlets provided on a periphery of said head combustion chamber and arranged in rows for introducing air from said annular passage into said head combustion chamber, said rows of combustion air inlets being spaced from each other and extending in a peripheral direction;
• an end wall provided for closing one end of said inner casing on the upstream side and having a plurality of annularly arranged air holes;
• a tubular member disposed in and coaxially with said head combustion chamber for defining an annular combustion space axially elongated and having a front end on the downstream side and a plurality of fine cooling air holes on a periphery thereof for introducing cooling-air from said annular air passage into said annular combustion space;
• means for producing diffusion combustion around said tubular member during operation of said combustor and vortex mixinbg between fuel and air, said means consisting of air inlet means at an upstream side of said annular combustion space for introducing air thereinto and a plurality of fuel nozzles for injecting fuel projecting into said annular combustion space through said air holes of said end wall such that the fuel injection holes of the fuel injection nozzles are positioned at a most upstream side row of said combustion air inlets, each of said air holes and each of said fuel nozzles passing through said air holes defining an annular air space for allowing air from said annular air passage to enter said head combustion chamber, said air inlet means including said annular air passage and at least one of said combustion air inlet rows, whereby said means, on one hand, injects fuel into said annular combustion space to produce the diffusion combustion, and on the other hand, produce the vortex mixing upstream of a fuel injection part of one or more of said nozzles;
• a plurality of air inlets having swirling vanes and disposed at a periphery of said rear combustion chamber on the upstream side of said rear combustion chamber so as to allow a flow of air in an axial direction of said rear combustion chamber while swirling the air along the periphery thereof;
• and
• a plurality of fuel nozzles for injecting fuel into said air inlets so that the fuel is mixed with air to produce a resultant fuel-air mixture flowing axially while swirling prior to introduction into the rear combustion chamber such that combustion of said mixture does not cause substantial interference with a combustion flame in said head combustion chamber.