Patent Publication Number: US-2021180518-A1

Title: Gas Turbine Combustor

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a gas turbine combustor (hereinafter, to be abbreviated as a “combustor”) and particularly relates to a combustor that distributes a fuel from one fuel header to a plurality of fuel nozzles. 
     2. Description of the Related Art 
     In a case of using a low nitrogen content fuel (natural gas, kerosene, light oil, or the like), most of NOx formed in a combustor is thermal NOx formed by oxidation of nitrogen in the air. Since thermal NOx formation highly depends on a temperature, a gas turbine using the low nitrogen content fuel normally seeks a NOx emissions reduction by controlling a flame temperature. 
     As measures for lowering the flame temperature, there is known premixed combustion for mixing a fuel with the air in advance and then burning a mixture. With the conventional premixed combustion, however, a phenomenon (flashback) of burning the fuel within a premixer possibly occurs in a case in which a temperature of the combustion air is high, a case in which a self-ignition temperature of the fuel is low, and the like. 
     To address the problem, a lean combustion approach to achieve a NOx emissions reduction by appropriately controlling a flame temperature while preventing a flashback is known (refer to, for example, JP-2018-128215-A). A combustor of this approach is configured with, for example, an air hole plate that has a plurality of small-diameter air holes; and a plurality of small-diameter fuel nozzles, injects a fuel from each fuel nozzle toward the corresponding air hole, and supplies many coaxial jets formed from a fuel stream and an air stream surrounding the fuel stream to a combustion chamber. 
     Patent Document 1: JP-2018-128215-A 
     In the case of achieving the NOx emissions reduction by supplying many coaxial jets to the combustion chamber, it is important to suppress unevenness of ratios of the fuel to the air (fuel-air ratio) among the coaxial jets. To suppress the unevenness, it is necessary to suppress deviations of air flow rates and fuel flow rates among the coaxial jets. 
     Causes for the unevenness of fuel flow rates of the coaxial jets include generation of distributions of fuel static pressures and fuel dynamic pressures of inlets among the fuel nozzles due to position relationships between a fuel inflow position relative to the fuel header (connection position of a fuel supply pipe) and inlets of the individual fuel nozzles. In other words, a fuel supply pipe is normally connected to only one portion of the fuel header, while many fuel nozzles are connected to the fuel header. A large area is necessary on a combustion chamber-side inner wall surface of the fuel header to attach the many fuel nozzles. Owing to this, the fuel nozzles differ in a distance to the fuel supply pipe, it is easier for the fuel to flow in the fuel nozzle that faces any of the fuel jets jetted from the fuel supply pipe to the fuel header, and it is more difficult for the fuel to flow in the fuel nozzle that has a large axial misalignment amount with respect to the fuel jets. While there is known a method of suppressing a deviation of fuel flow rates among the fuel nozzles by providing orifices on the fuel nozzles, installing the orifices on the many fuel nozzles disadvantageously causes increases in a man-hour count and a cost and also an increase in a pressure loss of the fuel. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a gas turbine combustor capable of suppressing a deviation of fuel injection amounts among a plurality of fuel nozzles connected to one fuel header and suppressing increases in a manufacturing man-hour count and in a pressure loss of a fuel. 
     To attain the object, the present invention provides a gas turbine combustor including: a cylindrical liner that forms a combustion chamber inside of the cylindrical liner; a plurality of fuel nozzles each disposed with an injection hole oriented toward the combustion chamber; a fuel header to which the plurality of fuel nozzles are connected; and a fuel supply flow passage connected to the fuel header. The fuel header includes a first chamber to which the fuel supply flow passage is connected, and a second chamber to which the plurality of fuel nozzles are connected. Further, an outlet of the fuel supply flow passage is opened in the first chamber, at least one communication opening communicating with the first chamber is opened in the second chamber, and the outlet of the fuel supply flow passage faces an inner wall surface of the first chamber. Furthermore, the second chamber includes a region spreading from the communication opening toward the combustion chamber, and inlets of the plurality of fuel nozzles are located closer to the combustion chamber than entirety of the communication opening. 
     According to the present invention, it is possible to suppress the deviation of fuel injection amounts among the plurality of fuel nozzles connected to one fuel header and suppress increases in the manufacturing man-hour count and in the pressure loss of the fuel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a gas turbine plant according to a first embodiment of the present invention; 
         FIG. 2  is an enlarged cross-sectional view representing a position relationship between a fuel nozzle and an air hole in a gas turbine combustor according to the first embodiment of the present invention; 
         FIG. 3  depicts an air hole plate viewed from a combustion chamber side and provided in the gas turbine combustor according to the first embodiment; 
         FIG. 4  is a perspective cross-sectional view taken along a line IV-IV of  FIG. 3 ; 
         FIG. 5  is a perspective cross-sectional view of an end cover taken along a line V-V of  FIG. 1 ; 
         FIG. 6  is a partial cross-sectional view of enlarged configurations of a fuel header provided in the gas turbine combustor according to the first embodiment of the present invention; 
         FIG. 7  is a cross-sectional view of a gas turbine combustor according to a second embodiment of the present invention; 
         FIG. 8  depicts an air hole plate viewed from the combustion chamber side and provided in the gas turbine combustor according to the second embodiment of the present invention; 
         FIG. 9  is a partial cross-sectional view of enlarged configurations of a fuel header provided in the gas turbine combustor according to the second embodiment of the present invention; 
         FIG. 10  is a perspective cross-sectional view of an end cover taken along a line X-X of  FIG. 7 ; 
         FIG. 11  is a cross-sectional view of a gas turbine combustor according to a third embodiment of the present invention; 
         FIG. 12  is a perspective cross-sectional view of an end cover taken along a line XII-XII of  FIG. 11 ; 
         FIG. 13  depicts an air hole plate viewed from the combustion chamber side and provided in the gas turbine combustor according to the third embodiment of the present invention; and 
         FIG. 14  is a cross-sectional view of a gas turbine combustor according to a fourth embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described hereinafter with reference to the drawings. 
     First Embodiment 
     Gas Turbine 
       FIG. 1  is a schematic diagram of a gas turbine plant according to a first embodiment of the present invention. In  FIG. 1 , a combustor  10  (to be described later) is illustrated by a cross-sectional view including a central axis O of a liner  11  (to be described later). It is noted that in a case of simply referring to “upstream” or “downstream” in the present specification, this means “upstream” or “downstream” with reference to a fuel injection direction (right direction in  FIG. 1 ) of fuel nozzles N 1  to N 3  (to be described later). In other words, in a case of, for example, a “region upstream of the liner  11 ,” this means a region leftward of the liner  11  in  FIG. 1 . 
     The gas turbine plant depicted in  FIG. 1  is configured with an electric generator  100  and a gas turbine  1  that serves as a prime mover driving this electric generator  100 . The gas turbine  1  is configured with a compressor  2 , the gas turbine combustor (hereinafter, to be abbreviated as a “combustor”)  10 , and a turbine  3 . The compressor  2  draws in and compresses air (atmosphere) A 1  and generates high-pressure compressed air A 2 . The combustor  10  mixes up combustion air guided from the compressor  2  with fuels (gaseous fuels) F 1  to F 3 , burns mixtures, and generates a combustion gas G 1 . The turbine  3  is driven by the combustion gas G 1  generated by the combustor  10 . The combustion gas G 1  that has driven the turbine  3  is emitted as exhaust gas G 2 . In the present embodiment, rotors (not depicted) of the compressor  2  and the turbine  3  are coupled to each other, the compressor  2  is driven by rotational power of the turbine  3 , and the electric generator  100  coupled to the compressor  2  is driven to generate electricity. It is noted that the gas turbine  1  is driven by a startup motor (not depicted) only at a time of start of startup. 
     Combustor 
     The combustor  10  is a so-called lean combustion type combustor and attached to a turbine casing (not depicted) of the gas turbine  1 . This combustor  10  is configured with the liner (combustion liner)  11 , a flow sleeve (combustor outer casing)  12 , a burner  20 , and a fuel supply system  50 . 
     Liner 
     The liner  11  is a member that is formed into a cylindrical shape and that forms a combustion chamber  13  thereinside, and is disposed downstream of an air hole plate (to be described later). An upstream end portion of the liner  11  surrounds an outer circumference of the air hole plate  21 . 
     Flow Sleeve 
     The flow sleeve  12  is a cylindrical member having a larger inside diameter than that of the liner  11  and surrounding an outer circumference of the liner  11 , and forms a cylindrical air flow passage  14  between the flow sleeve  12  and the liner  11 . The air hole plate  21  and fuel nozzles N 1  to N 3  are disposed inside of the flow sleeve  12 . An end portion of the flow sleeve  12  opposite to the turbine  3  (left side in  FIG. 1 ) is closed by an end cover (combustor cover)  15 . 
     The compressed air A 2  from the air compressor  2  circulates in the air flow passage  14  formed by the flow sleeve  12  around the liner  11  in a direction away from the turbine  3 , and an outer circumferential surface of the liner  11  is subjected to convection cooling by the compressed air A 2  flowing in the air flow passage  14 . In addition, many holes are formed in a wall surface of the liner  11 , part of the compressed air A 2  flowing in the air flow passage  14  flows into the combustion chamber  13  through those holes as cooling air A 3 , and an inner circumferential surface of the liner  12  is subjected to film cooling by the cooling air A 3 . Furthermore, the compressed air A 2  passing through the air flow passage  14  is supplied to the burner  20  as the combustion air A 4  and jetted, together with the gaseous fuels F 1  to F 3  supplied from the fuel supply system  50  to the burner  20 , from air holes H 1  to H 3  of the air hole plate  21  to the combustion chamber  13 . Air-fuel mixed gases of the fuels F 1  to F 3  and the combustion air A 4  jetted from the air holes H 1  to H 3  of the air hole plate  21  are burned in the combustion chamber  13  to generate the combustion gas G 1 , and the combustion gas G 1  is supplied to the turbine  3  via a transition piece (not depicted). 
     Burner 
       FIG. 2  is an enlarged cross-sectional view representing a position relationship between a fuel nozzle and an air hole in the combustor according to the present embodiment,  FIG. 3  depicts an air hole plate viewed from a combustion chamber side, and  FIG. 4  is a perspective cross-sectional view taken along a line IV-IV of  FIG. 3 .  FIG. 5  is a perspective cross-sectional view of an end cover taken along a line V-V of  FIG. 1 , and  FIG. 6  is a partial cross-sectional view of enlarged configurations of a fuel header D 2  (to be described later).  FIG. 6  does not depict a fuel header D 3  to be described later. 
     As depicted in  FIGS. 1 to 6 , the burner  20  is disposed upstream of the liner  11  and includes the air hole plate  21 , the fuel nozzles N 1  to N 3 , and fuel headers (fuel distributors) D 1  to D 3 . 
     The air hole plate  21  is a disc-like plate concentric with the liner  11 , is disposed in the upstream end portion (one axial side) of the liner  11 , and faces the combustion chamber  13 . A plurality of each of the air holes H 1  to H 3  for supplying the combustion air A 4  to the combustion chamber  13  are provided to penetrate through this air hole plate  21 . In the present embodiment, the air holes H 1  to H 3  configure concentric air hole rows around the central axis O of the liner  11 . The air holes H 1  form at least one annular air hole row (four rows in the present embodiment) in a central portion of the air hole plate  21  ( FIG. 3 ). The air holes H 1  configure a circular F 1  burner  20   a  that jets an air-fuel mixed gas of the fuel F 1  and the combustion air A 4 . The air holes H 2  form at least one annular air hole row (one row in the present embodiment) surrounding the F 1  burner  20   a  ( FIG. 3 ). The air holes H 2  configure an annular F 2  burner  20   b  that jets an air-fuel mixed gas of the fuel F 2  and the combustion air A 4 . The air holes H 3  form at least one air hole row (three rows in the present embodiment) surrounding the F 2  burner  20   b  ( FIG. 3 ). The air holes H 3  configure an annular F 3  burner  20   c  that jets an air-fuel mixed gas of the fuel F 3  and the combustion air A 4 . 
     In the present embodiment, it is noted that each of the air holes H 1  belonging to the central F 1  burner  20   a  has a rotation angle a ( FIG. 4 ), each air hole H 1  is inclined in a pitch circle tangential direction, and an outlet of each air hole H 1  is misaligned to one circumferential side with respect to an inlet thereof. The air-fuel mixed gas of the fuel F 1  and the combustion air A 4  is thereby turned as a whole, and a circulating flow generated by this rotation stabilizes a flame. Furthermore, a heat of combustion of the stable flame formed by the F 1  burner  20   a  stabilizes flames formed by the F 2  burner  20   b  and the F 3  burner  20   c.  While each of the air holes H 2  and H 3  belonging to the F 2  burner  20   b  or the F 3  burner  20   c  may have a rotation angle, the air holes H 2  and H 3  are set parallel to the central axis O in the present embodiment. 
     The fuel nozzles N 1  to N 3  are supported by the end cover  15  in the present embodiment, and disposed upstream of the air hole plate  21 , that is, disposed opposite to the combustion chamber  13  across the air hole plate  21 . The fuel nozzles N 1  to N 3  correspond to the air holes H 1  to H 3  in numbers and positions (one fuel nozzle corresponds to one air hole) in a view from the combustion chamber  13  side, and configure, together with the air holes H 1  to H 3 , the plurality of concentric annular rows around the central axis O of the liner  11 . Specifically, the fuel nozzles N 1  form at least one annular nozzle row (three rows in the present embodiment) so as to correspond to the air holes H 1 , and configure, together with the air holes H 1 , the F 1  burner  20   a  described above. The fuel nozzles N 2  form at least one annular nozzle rows (one row in the present embodiment) surrounding the F 1  burner  20   a  so as to correspond to the air holes H 2 , and configure, together with the air holes H 2 , the F 2  burner  20   b  described above. The fuel nozzles N 3  form at least one annular nozzle row (three rows in the present embodiment) surrounding the F 2  burner  20   b  so as to correspond to the air holes H 3 , and configure, together with the air holes H 3 , the F 3  burner  20   c  described above. The fuel nozzles N 1  to N 3  are installed each with an injection hole oriented toward an inlet of the corresponding air hole. While each fuel nozzle N 1  is disposed with the injection hole oriented toward the corresponding air hole H 1 , each fuel nozzle N 1  may be configured in such a manner that a tip end of the fuel nozzle N 1  is inserted into the corresponding air hole H 1  (the injection hole of the fuel nozzle N 1  is disposed within the air hole H 1 ). The same thing is true for the fuel nozzles N 2  and N 3 . 
     Each of the fuel nozzles N 1  to N 3  is attached to the end cover  15  in a posture in which the injection hole is oriented toward the combustion chamber  13  across the air hole plate  21 , and jets the fuel F 1 , F 2 , or F 3  to the combustion chamber  13  via the corresponding air hole. The fuels jetted from the fuel nozzles N 1  to N 3  are thereby covered with the combustion air A 4  jetted from the air holes to the combustion chamber  13  at the time of passing through the corresponding air holes, and the air-fuel mixed gases of the fuels and the combustion air A 4  are jetted to the combustion chamber  13  ( FIG. 2 ). Since the fuels passing through the air holes are not mixed with the combustion air A 4  yet, it is possible to prevent fuel self-ignition upstream of the air hole plate  21  and ensure high reliability of the combustor  10 . Furthermore, supplying the air-fuel mixed gases to the combustion chamber  13  using the many dispersed air holes makes it possible to increase interfaces between the fuels and the air, accelerate mixtures of the fuels and the air, and suppress an amount of formation of NOx. The lean combustion type combustor  10  according to the present embodiment can thereby achieve both a NOx emissions reduction and stable combustion. 
     Each of the fuel headers D 1  to D 3  is a columnar or annular space formed inside of the end cover  15 , distributes and supplies the fuel to a plurality of corresponding fuel nozzles. The fuel header D 1  belongs to the F 1  burner  20   a,  the fuel header D 2  belongs to the F 2  burner  20   b,  and the fuel header D 3  belongs to the F 3  burner  20   c.    
     The fuel header D 1  is the columnar space located on the central axis O, and a plurality of fuel nozzles N 1  are all connected to this fuel header D 1 . One fuel supply flow passage P 1  is connected to the fuel header D 1 . The fuel supply flow passage P 1  is a long and thin flow passage that is formed from a flange pipe P 1   a  and a communication flow passage P 1   b  and that has a circular cross-section, and extends onto the central axis O. The flange pipe P 1   a  is a cylindrical member having a flange provided in an end portion, and protrudes upstream from the end cover  15 . The communication flow passage P 1   b  is formed inside of the end cover  15 , and connects a hollow flow passage of the flange pipe P 1   a  to the fuel header D 1 . In the present embodiment, a downstream part of the communication flow passage P 1   b  has a conical shape, has a flow passage cross-sectional area that becomes larger as being closer to the fuel header D 1 , and has an outlet diameter coincident with an inside diameter of the fuel header D 1 . When the fuel F 1  is supplied from the fuel supply flow passage P 1  to the fuel header D 1 , the fuel F 1  with which the fuel header D 1  is filled is distributed to the fuel nozzles N 1  and jetted from the fuel nozzles N 1 . 
     The fuel header D 2  is an annular space formed to surround an outer circumference of the fuel header D 1 , and a plurality of fuel nozzles N 2  are all connected to this fuel header D 2 . One fuel supply flow passage P 2  is connected to the fuel header D 2 . The fuel supply flow passage P 2  is a long and thin flow passage (drilled hole) that is formed from a flange pipe P 2   a  and a communication flow passage P 2   b  and that has a circular cross-section, and extends in parallel to the central axis O at a position offset from the central axis O to an outer circumferential side of the end cover  15 . The flange pipe P 2   a  is a cylindrical member having a flange provided in an end portion, and protrudes upstream from the end cover  15 . The communication flow passage P 2   b  is formed inside of the end cover  15 , and connects a hollow flow passage of the flange pipe P 2   a  to the fuel header D 2 . Unlike the communication flow passage P 1   b  of the fuel supply flow passage P 1 , the communication flow passage P 2   b  of the fuel supply flow passage P 2  has a uniform flow passage cross-sectional area over an entire length and is connected to one portion out of an overall circumference of the ring-shaped fuel header D 2 . When the fuel F 2  is supplied from the fuel supply flow passage P 2  to the fuel header D 2 , the fuel F 2  with which the fuel header D 2  is filled is distributed to the fuel nozzles N 2  and jetted from the fuel nozzles N 2 . 
     The fuel header D 3  is an annular space formed to further surround an outer circumference of the fuel header D 2 , and a plurality of fuel nozzles N 3  are all connected to this fuel header D 3 . One fuel supply flow passage P 3  is connected to the fuel header D 3 . The fuel supply flow passage P 3  is a long and thin flow passage (drilled hole) that is formed from a flange pipe P 3   a  and a communication flow passage P 3   b  and that has a circular cross-section, and extends in parallel to the central axis O at a position further offset from the central axis O to the outer circumferential side of the end cover  15 , compared with the fuel supply flow passage P 2 . The flange pipe P 3   a  is a cylindrical member having a flange provided in an end portion, and protrudes upstream from the end cover  15 . The communication flow passage P 3   b  is formed inside of the end cover  15 , and connects a hollow flow passage of the flange pipe P 3   a  to the fuel header D 3 . Similarly to the communication flow passage P 2   b  of the fuel supply flow passage P 2 , the communication flow passage P 3   b  of the fuel supply flow passage P 3  has a uniform flow passage cross-sectional area over an entire length and is connected to one portion out of an overall circumference of the ring-shaped fuel header D 3 . When the fuel F 3  is supplied from the fuel supply flow passage P 3  to the fuel header D 3 , the fuel F 3  with which the fuel header D 3  is filled is distributed to the fuel nozzles N 3  and jetted from the fuel nozzles N 3 . 
     Detailed configurations of the fuel headers D 2  and D 3  will be described later. 
     Fuel Supply System 
     The fuel supply system  50  is configured with an F 1  fuel supply system, an F 2  fuel supply system, and an F 3  fuel supply system. A main flow pipe (not depicted) extending from a fuel supply source (not depicted) branches off into three pipes, and these branch pipes configure pipes of the F 1  fuel supply system, the F 2  fuel supply system, and the F 3  fuel supply system, respectively. The pipe of the F 1  fuel supply system is connected to the flange pipe P 1   a  of the fuel supply flow passage P 1 , the pipe of the F 2  fuel supply system is connected to the flange pipe P 2   a  of the fuel supply flow passage P 2 , and the pipe of the F 3  fuel supply system is connected to the flange pipe P 3   a  of the fuel supply flow passage P 3 . A shut-off valve V 11  and a fuel control valve V 12  are provided in the pipe of the F 1  fuel supply system. Likewise, a shut-off valve V 21  and fuel control valve V 22  are provided in the pipe of the F 2  fuel supply system, and a shut-off valve V 31  and a fuel control valve V 32  are provided in the pipe of the F 3  fuel supply system. Supply of the fuels to the F 1  fuel supply system, the F 2  fuel supply system, and the F 3  fuel supply system can be shut off by the shut-off valves V 11 , V 21 , and V 31 , individually. Flow rates of the fuels flowing in the pipes of the F 1  fuel supply system, the F 2  fuel supply system, and the F 3  fuel supply system can be regulated by the fuel control valves V 12 , V 22 , and V 32 , individually. In this way, the F 1  burner  20   a,  the F 2  burner  20   b,  and the F 3  burner  20   c  can individually jet the fuels or stop jetting the fuels, and also individually regulate the fuel injection flow rates of the F 1  burner  20   a,  the F 2  burner  20   b,  and the F 3  burner  20   c.    
     It is noted that the fuels F 1  to F 3  supplied from the fuel supply source (not depicted) are, for example, gaseous fuels, and not only a natural gas that is a standard gas turbine fuel but also a gas containing hydrogen or carbon monoxide such as a petroleum gas, a coke oven gas, an oil refinery off-gas, and a coal gas can be used as the fuels F 1  to F 3 . 
     Fuel Header D 2   
     As depicted in  FIG. 6  as an enlarged view, the fuel header D 2  described above is configured with two hollow spaces, that is, a first chamber D 21  and a second chamber D 22 , and a communication flow passage C 2  communicating the first chamber D 21  with the second chamber D 22 . 
     First Chamber D 21   
     The first chamber D 21  is formed into a ring shape, and disposed to surround an outer side of the second chamber D 22  in a liner radial direction. This first chamber D 21  is defined by a downstream wall surface (first downstream wall surface) D 21   a,  an upstream wall surface (first upstream wall surface) D 21   b,  an inner circumferential wall surface (first inner circumferential side wall surface) D 21   c,  and an outer circumferential wall surface (first outer circumferential side)  21   d.  The downstream wall surface D 21   a  is a wall surface facing an opposite side to the combustion chamber  13  ( FIG. 1 ) (that is, closer to the combustion chamber  13 ), and formed into a ring shape around the central axis O. The upstream wall surface D 21   b  is a wall surface facing the downstream wall surface D 21   a  (that is, farther from the combustion chamber  13 ), and formed into a ring shape around the central axis O so as to correspond to the downstream wall surface D 21   a.  The inner circumferential wall surface D 21   c  is a wall surface closer to the central axis O in the first chamber D 21 , extends cylindrically along the central axis O, and connects inner circumferences of the downstream wall surface D 21   a  and the upstream wall surface D 21   b  to each other. The outer circumferential wall surface D 21   d  is a wall surface facing the inner circumferential wall surface D 21   c  (that is, farther from the central axis O in the first chamber D 21 ), extends cylindrically along the central axis O, and connects outer circumferences of the downstream wall surface D 21   a  and the upstream wall surface D 21   b  to each other. 
     The fuel supply flow passage P 2  (communication flow passage P 2   b ) is connected to the first chamber D 21 . The outlet P 2   c  of the fuel supply flow passage P 2  is opened in the upstream wall surface D 21   b  of the first chamber D 21 . The outlet P 2   c  of the fuel supply flow passage P 2  faces an inner wall surface (downstream wall surface D 21   a  in the present example) of the first chamber D 21 , and is misaligned with respect to inlets N 2   a  of all of the plurality of fuel nozzles N 2  opened in the second chamber D 22  in the liner radial direction (to an outer circumferential side in the present example) as described later. 
     Second Chamber D 22   
     The second chamber D 22  is formed into a ring shape having a smaller diameter than that of the first chamber D 21  and disposed on an inner circumferential side of the first chamber D 21 . This second chamber D 22  is defined by a downstream wall surface (second downstream wall surface) D 22   a,  an upstream wall surface (second upstream wall surface) D 22   b,  an inner circumferential wall surface (second inner circumferential side wall surface) D 22   c,  and an outer circumferential wall surface (second outer circumferential side)  22   d.  The downstream wall surface D 22   a  is a wall surface facing the opposite side to the combustion chamber  13  ( FIG. 1 ) (that is, closer to the combustion chamber  13 ), and formed into a ring shape around the central axis O. The upstream wall surface D 22   b  is a wall surface facing the downstream wall surface D 22   a  (that is, farther from the combustion chamber  13 ), and formed into a ring shape around the central axis O so as to correspond to the downstream wall surface D 22   a.  The inner circumferential wall surface D 22   c  is a wall surface closer to the central axis O in the second chamber D 22 , extends cylindrically along the central axis O, and connects inner circumferences of the downstream wall surface D 22   a  and the upstream wall surface D 22   b  to each other. The outer circumferential wall surface D 22   d  is a wall surface facing the inner circumferential wall surface D 22   c  (that is, closer to the first chamber D 21 ), extends cylindrically along the central axis O, and connects outer circumferences of the downstream wall surface  22   a  and the upstream wall surface D 22   b  to each other. 
     The plurality of fuel nozzles N 2  are connected to the second chamber D 22 . The inlets N 2   a  of all the fuel nozzles N 2  are opened in the downstream wall surface D 22   a  of the second chamber D 22 . The inlets N 2   a  of the fuel nozzles N 2  face the upstream wall surface D 22   b  of the second chamber D 22 , and are misaligned with respect to the outlet P 2   c  of the fuel supply flow passage P 2  in the liner radial direction (to the inner circumferential side) as described above. Furthermore, a communication opening C 2   a  is opened in the outer circumferential wall surface D 22   d  of the second chamber D 22 , and this communication opening C 2   a  faces the inner circumferential wall surface D 22   c  of the second chamber D 22 . The communication opening C 2   a  is an outlet of the communication flow passage C 2  and in communication with the first chamber D 21 . The second chamber D 22  is configured with a region D 22   x  ( FIG. 6 ) spreading from this communication opening C 2   a  toward the combustion chamber  13  (downstream). The inlets N 2   a  of the plurality of (all the) fuel nozzles N 2  are thereby located closer to the combustion chamber  13  than entirety of the communication opening C 2   a.  In the present embodiment, the second chamber D 22  is formed to be thicker downstream along the central axis O than the first chamber D 21 . It is assumed that a dimension of the region D 22   x  in a direction of extension of the central axis O is, for example, equal to or greater than an opening diameter of the communication opening C 2   a.  Moreover, the fuel F 2  flowing in the communication flow passage C 2  is jetted inward in the liner radial direction (in a direction across a direction of a flow in the fuel nozzles N 2 ) at a position apart from the inlet N 2   a  of the closest fuel nozzle N 2  (closest to the communication opening C 2   a ) in the second chamber D 22  by the region D 22   x.    
     Communication Flow Passage C 2   
     The communication flow passage C 2  extends in the liner radial direction and communicates the first chamber D 21  with the second chamber D 22 . An inlet of the communication flow passage C 2  is opened in the inner circumferential wall surface D 21   c  of the first chamber D 21 , and the outlet (communication opening C 2   a ) thereof is opened in the outer circumferential wall surface D 22   d  of the second chamber D 22  to face the inner circumferential wall surface D 22   c  as described above. In the present embodiment, a dimension of the communication flow passage C 2  in a liner axial direction (along the central axis O) is set smaller than dimensions of the first chamber D 21  and the second chamber D 22  in the same direction. For example, a plurality of sets of communication openings C 2   a  (outlets of the communication flow passage C 2 ) are provided in the liner circumferential direction, and the first chamber D 21  and the second chamber D 22  communicate with each other in a plurality of circumferential portions. Alternatively, the header D 2  can be configured in such a manner that the communication opening C 2   a  and the communication flow passage C 2  are each formed into a ring shape, and that the first chamber D 21  and the second chamber D 22  communicate with each other over entire circumferences. 
     Fuel Header D 3   
     Similarly to the fuel header D 2 , the fuel header D 3  is configured with two hollow spaces, that is, a first chamber D 31  and a second chamber D 32 , and a communication flow passage C 3  communicating the first chamber D 31  with the second chamber D 32 . The second chamber D 32  of the fuel header D 3  is disposed between the first chamber D 31  of the fuel header D 3  and the second chamber D 22  of the fuel header D 2 , and located downstream of the first chamber D 21  of the fuel header D 2 . The first chamber D 31  and the second chamber D 32  are nearly identical in a dimension in the liner axial direction. Configurations of the fuel header D 3  are substantially similar to those of the fuel header D 2  except for this respect. In the second chamber D 32 , a communication opening (outlet of the communication flow passage C 3 ) is opened at a position apart downstream from inlets of the fuel nozzles N 3 . Furthermore, the second chamber D 32  is configured with a region (corresponding to the region D 22   x  of  FIG. 6 ) spreading from the communication opening toward the combustion chamber  13  (downstream), and the inlets of the plurality of (all the) fuel nozzles N 3  are located closer to the combustion chamber  13  than entirety of the communication opening. 
     Operations 
     F 1  Burner 
     Upon opening the shut-off valve V 11 , the fuel F 1  is supplied from the F 1  fuel supply system to the F 1  burner  20   a,  and an injection flow rate of the fuel F 1  from the F 1  burner  20   a  is controlled by control of an opening degree of the fuel control valve V 12 . The fuel F 1  supplied from the F 1  fuel supply system is delivered through the fuel supply flow passage P 1 , supplied to the fuel header D 1 , and distributed to the plurality of fuel nozzles N 1 . The fuel F 1  jetted from each fuel nozzle N 1  passes, together with the combustion air A 4 , through the corresponding air hole H 1  and is jetted to the combustion chamber  13 . At this time, the fuel F 1  supplied to the fuel header D 1  decelerates according to a gentle increase in a flow passage cross-sectional area of the fuel supply flow passage P 1 ; thus, it is possible to suppress a deviation of flow rates of the fuel F 1  flowing in the fuel nozzles N 1  without dividing the fuel header D 1  into two chambers. 
     F 2  Burner 
     Upon opening the shut-off valve V 21 , the fuel F 2  is supplied from the F 2  fuel supply system to the F 2  burner  20   b,  and an injection flow rate of the fuel F 2  from the F 2  burner  20   b  is controlled by control of an opening degree of the fuel control valve V 22 . The fuel F 2  supplied from the F 2  fuel supply system is delivered through the fuel supply flow passage P 2 , and supplied to the first chamber D 21  of the fuel header D 1 . The fuel F 2  jetted from the second fuel supply flow passage P 2  to the first chamber D 21  collides against the opposed downstream wall surface D 21   a  to reduce a dynamic pressure of the fuel F 2 , the first chamber D 21  is filled with the fuel F 2 , and the fuel F 2  flows in the second chamber D 22  through the communication flow passage C 2 . The fuel F 2  jetted from the communication flow passage C 2  collides against the inner circumferential wall surface D 22   c  of the second chamber D 22  at the position apart from the inlets N 2   a  of the fuel nozzles N 2  by the region D 22   x,  and the second chamber D 22  is filled with the fuel F 2 . The fuel F 2  with which the second chamber D 22  is filled in this way is distributed to the fuel nozzles N 2 . The fuel F 2  jetted from each fuel nozzle N 2  passes, together with the combustion air A 4 , through the corresponding air hole H 2  and is jetted to the combustion chamber  13 . 
     F 3  Burner 
     The F 3  burner  20   c  operates similarly to the F 2  burner  20   b.  In other words, upon opening the shut-off valve V 31 , the fuel F 3  is supplied from the F 3  fuel supply system to the F 3  burner  20   c,  and an injection flow rate of the fuel F 3  from the F 3  burner  20   c  is controlled by control of an opening degree of the fuel control valve V 32 . The fuel F 3  jetted to the first chamber D 31  collides against the opposed downstream wall surface (corresponding to the downstream wall surface D 21   a  of the first chamber D 21 ) to reduce a dynamic pressure of the fuel F 3 , and flows in the second chamber D 32  through the communication flow passage C 3 . The fuel F 3  jetted from the communication flow passage C 3  collides against the inner circumferential wall surface at a position apart from the inlets of the fuel nozzles N 3  by a distance (corresponding to the region D 22   x ), the second chamber D 32  is filled with the fuel F 3 , and the fuel F 3  is distributed to the fuel nozzles N 3 . The fuel F 3  jetted from each fuel nozzle N 3  passes, together with the combustion air A 4 , through the corresponding air hole H 3 , and is jetted to the combustion chamber  13 . 
     Advantages 
     Since the F 2  burner  20   b  surrounding the central F 1  burner  20   a  is formed into the ring shape, the fuel header D 2  of the F 2  burner  20   b  is also ring-shaped. On the other hand, since the fuel supply flow passage P 2  is a long and thin hole that has the circular cross-section, the fuel supply flow passage P 2  is connected to one circumferential portion of the ring-shaped fuel header D 2 . If the fuel header D 2  is one doughnut-shaped chamber without division into the two chambers, a deviation of flow rates of the fuel F 2  flowing in the fuel nozzles N 2  is possibly generated depending on distances to the outlet P 2   c  of the fuel supply flow passage P 2 . 
     In the present embodiment, by contrast, the fuel header D 2  is divided into the two chambers, that is, the first chamber D 21  and the second chamber D 22 , and the first chamber D 21  temporarily receives the fuel F 2  supplied from the fuel supply flow passage P 2 . The outlet P 2   c  of the fuel supply flow passage P 2  is misaligned with respect to the inlets N 2   a  of all the fuel nozzles N 2 , and the fuel F 2  guided into the first chamber D 21  collides against the downstream wall surface D 21   a  of the first chamber D 21  to reduce the dynamic pressure and turns. Owing to this, the subsequent deviation of flow rates can be suppressed for amounts of the fuel flowing in the fuel nozzles N 2  and eventually amounts of the fuel injected from the fuel nozzles N 2 . 
     Furthermore, at a time of jetting the fuel F 2  to the second chamber D 22  of the fuel header D 2 , the fuel F 2  jetted from the communication flow passage C 2  passes across the inlet N 2   a  of the closest fuel nozzle N 2  if the communication opening C 2   a  is provided in a downstream end portion of the outer circumferential wall surface D 22   d  of the second chamber D 22 . In other words, the fuel F 2  jetted from the communication flow passage C 2  is a shear flow, as opposed to a flow of the fuel F 2  flowing in the fuel nozzles N 2 . In this case, even if the dynamic pressure of the fuel F 2  is reduced in the first chamber D 21 , then a static pressure difference affects an inflow operation of the fuel F 2  to the fuel nozzles N 2  depending on a jet speed of the fuel F 2  to the second chamber D 22 , and a deviation tends to be generated in fuel injection flow rates of the fuel nozzles N 2 . 
     In the present embodiment, by contrast, the fuel F 2  is apart from the inlets N 2   a  of the fuel nozzles N 2  by the region D 22   x  in the second chamber D 22 . Owing to this, it is difficult for the static pressure difference caused by the jet speed of the fuel F 2  to affect the inflow operation of the fuel F 2  to the fuel nozzles N 2 , and the deviation of the fuel injection flow rates among the fuel nozzles N 2  is suppressed. 
     As described so far, it is possible to suppress the deviation of fuel injection amounts among the plurality of fuel nozzles N 2  connected to the same fuel header D 2  and suppress increases in a manufacturing man-hour count and a pressure loss of the fuel even without providing an orifice on each fuel nozzle N 2 . A similar principle applies to the F 3  burner  20   c,  and it is possible to suppress the deviation of fuel injection amounts among the fuel nozzles N 3  while suppressing increases in the manufacturing man-hour count and the pressure loss of the fuel. Moreover, in the F 1  burner  20   a,  the deviation of fuel injection amounts among the fuel nozzles N 1  is small, as described above. Furthermore, since the deviations of fuel injection amounts among the fuel nozzles can be suppressed in the F 1  burner  20   a,  the F 2  burner  20   b,  and the F 3  burner  20   c,  it is possible to achieve a NOx emissions reduction of the gas turbine  1 . Moreover, it is possible to dispense with a compressor for fuel pressure rising or reduce pressure rising power. 
     Second Embodiment 
       FIG. 7  is a cross-sectional view of a combustor according to a second embodiment of the present invention, and  FIG. 8  depicts an air hole plate according to the present embodiment viewed from the combustion chamber side.  FIG. 9  is a partial cross-sectional view of enlarged configurations of a fuel header provided in the combustor according to the present embodiment, and  FIG. 10  is a perspective cross-sectional view of an end cover taken along a line X-X of  FIG. 7 . Similar or corresponding elements to those according to the first embodiment are denoted by the same reference characters as those depicted in  FIGS. 1 and 3  in  FIGS. 7 to 10 , and description thereof will be omitted. The combustor according to the present embodiment differs from the combustor according to the first embodiment in configurations of the F 2  burner  20   b.  Second chambers D 22  of the fuel header D 2  of the F 2  burner  20   b,  the fuel nozzles N 2 , and the air holes H 2  are disposed to be distributed in a plurality of circumferential portions (six portions in the present example), and the first chamber D 21  and the second chamber D 22  of the fuel header D 2  are disposed side by side in the direction of extension of the central axis O. 
     In the present embodiment, configurations of the F 1  burner  20   a  are identical to those according to the first embodiment. While configurations of the F 3  burner  20   c  are generally similar to those according to the first embodiment, the F 2  burner  20   b  does not lie between the F 3  burner  20   c  and the F 1  burner  20   a.  The air holes H 3  configuring the F 3  burner  20   c  form at least one annular air hole row (four rows in the present embodiment) surrounding the F 1  burner  20   a  ( FIG. 8 ), and the fuel nozzles N 3  are disposed so as to correspond to the air holes H 3 . The fuel nozzles N 3  are connected to the second chamber D 32  of the fuel header D 3 , similarly to the first embodiment. 
     On the other hand, the air holes H 2  configuring the F 2  burner  20   b  are present so as to cut in on installation areas of the air holes H 3  of the F 3  burner  20   c  in the air hole plate  21  and form a plurality of (six in the present example) air hole groups at equidistant intervals in the circumferential direction. In each group, each of a plurality of air holes H 2  has the rotation angle ( FIG. 4 ) similarly to the air holes H 1  of the F 1  burner  20   a.  A plurality of groups (six groups in the present example) of fuel nozzles N 2  are provided so as to correspond to the air holes H 2 , and each fuel nozzle N 2  is installed with the injection hole oriented toward the corresponding air hole H 2 . 
     The fuel header D 2  has the first chamber D 21  and the second chamber D 22  similarly to the first embodiment. However, while having one first chamber D 21 , the fuel header D 2  has a plurality of (six in the present example) second chambers D 22  in the present embodiment. Each second chamber D 22  is connected to the first chamber D 21  via the communication opening C 2   a  without via the communication flow passage. 
     The first chamber D 21  according to the present embodiment has similar configurations to those according to the first embodiment, and is formed into the ring shape by the downstream wall surface D 21   a,  the upstream wall surface D 21   b,  the inner circumferential wall surface D 21   c,  and the outer circumferential wall surface D 21   d.  The fuel supply flow passage P 2  (communication flow passage P 2   b ) is connected to the first chamber D 21 . The outlet P 2   c  of the fuel supply flow passage P 2  is opened in the upstream wall surface D 21   b  of the first chamber D 21 . The outlet P 2   c  of the fuel supply flow passage P 2  is completely misaligned with respect to any of the second chambers D 22  in the circumferential direction, and faces the inner wall surface of the first chamber D 21  (downstream wall surface  21   a  between the two adjacent second chambers D 22 ). The outlet P 2   c  of the fuel supply flow passage P 2  is thereby misaligned with respect to all of the second chambers D 22  and eventually the inlets N 2   a  of all of the plurality of fuel nozzles N 2  opened in each second chamber D 22  in the liner circumferential direction ( FIG. 10 ). 
     On the other hand, each second chamber D 22  of the fuel header D 2  is formed as a columnar space defined by a downstream wall surface (second downstream wall surface) D 22 A and an inner circumferential surface D 22 B. The downstream wall surface D 22 A is a circular plane surface facing the opposite side to the combustion chamber  13 . The inner circumferential surface D 22 B is a cylindrical circumferential surface extending downstream from an outer edge of the downstream wall surface D 22 A. In each second chamber D 22 , an end portion facing the downstream wall surface D 22 A, that is, an upstream end portion is entirely opened as the communication opening C 2   a  with the first chamber D 21 . In each second chamber D 22 , a plurality of fuel nozzles N 2  (only one fuel nozzle N 2  is depicted in  FIG. 9 ) are connected to the downstream wall surface D 22 A. A plurality of second chambers D 22  configured in this way are disposed annularly, and connected to the downstream wall surface D 21   a  of the same first chamber D 21  via the communication openings C 2   a.  While each communication opening C 2   a  faces the inlets N 2   a  of the fuel nozzles N 2  in the present embodiment, the second chamber D 22  having a larger diameter than that of the inlets N 2   a  lies between the communication opening C 2   a  and the inlets N 2   a.  In the present embodiment, an entire length of each second chamber D 22  in the direction of extension of the central axis O corresponds to the region D 22   x  described above. It is assumed that the dimension of the region D 22   x  in the direction of extension of the central axis O is, for example, equal to or greater than the opening diameter of each communication opening C 2   a  (that is, the second chamber D 22  extends along the central axis O). 
     Other configurations are similar to those according to the first embodiment. 
     In the present embodiment, the F 1  burner  20   a  and the F 3  burner  20   c  operate similarly to those according to the first embodiment. As for each F 2  burner  20   b,  upon opening the shut-off valve V 21 , the fuel F 2  is supplied from the F 2  fuel supply system to the F 2  burner  20   b,  and the injection flow rate of the fuel F 2  from the F 2  burner  20   b  is controlled by control of the opening degree of the fuel control valve V 22 , similarly to the first embodiment. The fuel F 2  supplied from the F 2  fuel supply system is delivered through the fuel supply flow passage P 2 , and supplied to the first chamber D 2   l  of the fuel header D 1 . The fuel F 2  jetted from the fuel supply flow passage P 2  to the first chamber D 2   l  collides against the opposed downstream wall surface D 21   a  to reduce the dynamic pressure of the fuel F 2 , the ring-shaped first chamber D 2   l  is filled with the fuel F 2 , and the fuel F 2  is distributed to flow in the plurality of second chambers D 22  via the communication openings C 2   a.  In each second chamber D 22 , the region D 22   x  is filled with the fuel F 2  flowing from the communication opening C 2   a,  and the fuel F 2  is distributed to the fuel nozzles N 2  from the inlets N 2   a  apart by the region D 22   x.  Furthermore, the fuel F 2  jetted from each fuel nozzle N 2  passes, together with the combustion air A 4 , through the corresponding air hole H 2  and jetted to the combustion chamber  13 . In the present embodiment, each air hole H 2  configuring each F 2  burner  20   b  has the rotation angle; thus, the fuel F 2  jetted from the F 2  burner  20   b  forms a circulating flow by the rotation and stabilizes a flame, similarly to the fuel F 1  jetted from the F 1  burner  20   a.  The heat of combustion of each F 2  burner  20   b  can further stabilize the flame by the F 3  burner  20   c,  and improve combustion stability at a time of a partial load at which the injection amount of the fuel F 2  does not reach a fixed amount. 
     While the fuel F 2  flows in each second chamber D 22  in a fuel injection direction by each of the fuel nozzles N 2  in the fuel header D 2  according to the present embodiment, the inlet N 2   a  of each fuel nozzle N 2  is apart from the communication opening C 2   a  by the region D 22   x  within the second chamber D 22 . Owing to this, it is difficult for the static pressure difference due to a speed of the fuel F 2  flowing from the first chamber D 21  in each second chamber D 22  to affect the inflow operation of the fuel F 2  to the fuel nozzles N 2 . Thus, the present embodiment can obtain similar advantages to those of the first embodiment. 
     Third Embodiment 
       FIG. 11  is a cross-sectional view of a combustor according to a third embodiment of the present invention,  FIG. 12  is a perspective cross-sectional view of an end cover taken along a line XII-XII of  FIG. 11 , and  FIG. 13  depicts an air hole plate according to the present invention viewed from the combustion chamber side.  FIGS. 11 to 13  correspond to  FIGS. 7, 10, and 8  according to the second embodiment, respectively, elements similar or corresponding to those according to the second embodiment are denoted by the same reference characters as those depicted in  FIGS. 7, 10, and 8  in  FIGS. 11 to 13 , and description thereof will be omitted. The combustor according to the present embodiment differs from the combustor according to the second embodiment in that the outlet P 2   c  of the fuel supply flow passage P 2  is misaligned with respect to all of a plurality of second chambers D 22  of the fuel header D 2  in the liner radial direction in the F 2  burners  20   b.  In the present embodiment, a downstream end of the fuel supply flow passage P 2  (communication flow passage P 2   b ) is bent inward in the liner radial direction. The outlet P 2   c  of the fuel supply flow passage P 2  is opened in the outer circumferential wall surface D 22   d  (refer to  FIG. 6 ) of the fuel header D 2  and faces the inner circumferential wall surface D 21   c  (refer to  FIG. 6 ) that is the inner wall surface of the first chamber D 21 . Furthermore, in the present embodiment, the outlet P 2   c  of the fuel supply flow passage P 2  is misaligned with respect to all the second chambers D 22  in the liner circumferential direction ( FIG. 12 ). 
     The present embodiment is similar to the second embodiment in the other configurations. 
     In the present embodiment, the outlet P 2   c  of the fuel supply flow passage P 2  is similarly misaligned with respect to the inlets N 2   a  of all the fuel nozzles N 2 ; thus, the fuel F 2  guided into the first chamber D 21  collides against the inner circumferential wall surface D 21   c  of the first chamber D 21  to reduce the dynamic pressure. Owing to this, the present embodiment can obtain similar advantages to those of the second embodiment. Particularly in the present embodiment, an effect to suppress the deviation of flow rates is high since the outlet P 2   c  of the fuel supply flow passage P 2  is misaligned with respect to all the second chambers D 22  in both the circumferential direction and the radial direction. 
     Fourth Embodiment 
       FIG. 14  is a cross-sectional view of a combustor according to a fourth embodiment of the present invention.  FIG. 14  corresponds to a combustor part depicted in  FIG. 1  according to the first embodiment, similar or corresponding elements to those according to the first embodiment are denoted by the same reference characters as those in  FIG. 1  in  FIG. 14 , and description thereof will be omitted. The combustor according to the present embodiment differs from the combustor according to the first embodiment in that the communication flow passage C 2  is not provided in the fuel header D 2  and the first chamber D 21  directly communicates with the second chamber D 22 . In other words, inner wall surfaces of both the first chamber D 21  and the second chamber D 22  are opened in a way of sharing the communication opening C 2   a  therebetween. The fuel header D 3  is similarly configured. 
     The present embodiment is similar to the first embodiment in the other configurations. Even with such configurations, the present embodiment can obtain similar advantages to those of the first embodiment by ensuring the distance along the central axis O (region D 22   x  described with reference to  FIG. 6 ) between the inlets N 2   a  of the fuel nozzles N 2  and the communication opening C 2   a  in the second chamber D 22  similarly to the first embodiment. The same thing is true for the fuel header D 3 . 
     Modification 
     While it is not always necessary to provide orifices in the fuel nozzles N 1  to N 3  to make uniform the fuel flow rates of many fuel nozzles present in the embodiments described so far, it is allowed to install orifices in part of or all of the fuel nozzles N 1  to N 3  as needed. 
     Furthermore, the configuration, for example, such that the first chamber D 21  of the fuel header D 2  surrounds the outer circumference of the second chamber D 22  has been exemplarily described in the first embodiment. However, the fuel header D 2  may be configured in such a manner that the first chamber D 21  is disposed, for example, on the inner circumferential side of the second chambers D 22  if it is necessary to change a position relationship due to a relationship with the other constituent elements. The same thing is true for the fuel header D 2  and the other embodiments. 
     While the combustor configured with the three burners, that is, the F 1  burner  20   a,  the F 2  burner  20   b,  and the F 3  burner  20   c  has been exemplarily described, the present invention is also applicable to a combustor with the number of burners equal to or smaller than two or equal to or greater than four.