JP2007309644A - Combustor for gas turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustor for a gas turbine with uniform combustion in both gas firing and oil firing. <P>SOLUTION: An inner cylinder of the combustor is formed into a trumpet shape with a diameter getting larger along toward a downstream. Oil is prevented from accumulating because a low-velocity area is not generated in the trumpet shape. The oil is further film-cooled by cooling air from a cooling hole having a shape free from a step difference of depositing the oil. A spacer getting to a cause of the low-velocity area of depositing the oil is not installed in the cooling hole. The oil in the vicinity of the cooling hole is blown off by the cooling air. The cooling hole is constituted to make an opening get larger in a portion with a higher calorific value. The used cooling air is small in a portion with a lower calorific value, and the air saved thereby is used for combustion. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a combustor for a gas turbine.

  Since the combustor for gas turbine becomes high temperature, an effective cooling means is required. Furthermore, a combustor that reduces NOx is required for environmental considerations. Furthermore, the development of combustors that use both gas and oil as fuel is underway.

  In a combustor that reacts fuel and compressed air to generate combustion gas and guides the combustion gas to the turbine part, an inner cylinder part that generates the combustion gas, and a tail cylinder that leads the combustion gas to the turbine part And a combustor characterized in that they are integrally formed. The combustor is provided with wall surface cooling means for cooling the wall surface of the combustor part composed of an inner cylinder part and a tail cylinder (see Patent Document 1).

JP 2003-201863 A

An object of the present invention is to provide a combustor whose wall surface is uniformly cooled.
Another object of the present invention is to provide a combustor in which combustion is performed uniformly.
Still another object of the present invention is to provide a combustor that burns oil more completely when oil is used as fuel.
Still another object of the present invention is to provide a combustor with low combustion vibration.
Still another object of the present invention is to provide a combustor that saves cooling air and provides more combustion air.

  In the following, means for solving the problem will be described using the numbers used in [Best Mode for Carrying Out the Invention] in parentheses. These numbers are added to clarify the correspondence between the description of [Claims] and [Best Mode for Carrying Out the Invention]. However, these numbers should not be used to interpret the technical scope of the invention described in [Claims].

  The gas turbine combustor (1) according to the present invention includes a combustion cylinder (2) that forms a combustion area (8) therein, and an acoustic wave installed in a predetermined area outside the combustion area (8) of the combustion cylinder (2). A box (5) is provided. The acoustic box (5) has a drain hole (49) for discharging oil.

  In the gas turbine combustor (1) according to the present invention, in the combustion cylinder (2), the coolant flows between the inner wall surface facing the combustion region (8) and the outer wall surface facing the outside of the combustion cylinder (2). It has a cooling groove (36a, 45, 46, 47). The combustion cylinder (2) is provided with a plurality of sound absorbing holes (16) that connect the inside of the acoustic box (5) and the combustion region (8) in a predetermined region. The cooling groove includes a first cooling groove (45) provided so as not to communicate with the sound absorbing hole (16) in a predetermined region, and a second cooling groove (46) provided in a region other than the predetermined region.

  In the gas turbine combustor (1) according to the present invention, the sound absorption hole (16) has a large opening ratio in a portion close to an extension line in which the nozzle (14) for injecting fuel into the combustion region (8) is extended downstream.

  In the gas turbine combustor (1) according to the present invention, the nozzle (14) for injecting fuel into the combustion region (8) is extended to the downstream side with respect to the central axis of the combustion cylinder (2) in the predetermined region. A portion that is separated from the line by a predetermined angle or more in the circumferential direction of the combustion cylinder (2) is not provided with the sound absorbing hole (16).

  In the gas turbine combustor (1) according to the present invention, the drain hole (49) is provided at the lowest position in the vertical direction of the acoustic box when the gas turbine combustor is installed in an operating state. Yes.

  In the gas turbine combustor (1) according to the present invention, a plurality of drain holes (49) are provided. When all the acoustic boxes (5) installed in the combustion cylinder (2) are installed in a state where the gas turbine combustor is operated, any one of the plurality of drain holes (49) is in the vertical direction. The lowest position.

According to the present invention, a combustor whose wall surface is uniformly cooled is provided.
Furthermore, according to the present invention, a combustor in which combustion is performed uniformly is provided.
Furthermore, the present invention provides a combustor that burns oil more completely when oil is used as fuel.
Furthermore, according to the present invention, a combustor with low combustion vibration is provided.
Furthermore, the present invention provides a combustor that saves cooling air and increases the amount of combustion air.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  Referring to FIG. 1, a gas turbine combustor 1 is shown. The combustor 1 is installed in a passenger compartment 4 formed by a passenger compartment wall fixed to the ground. The combustor 1 includes a combustion cylinder 2 that forms a combustion region therein, and a tail cylinder 3 connected to the downstream side of the combustion cylinder 2 (the side close to the turbine). Conventionally, the combustion cylinder is usually a straight cylindrical combustion cylinder having a substantially constant cross-sectional area perpendicular to the central axis. The combustion cylinder 2 in the present embodiment has a trumpet shape that is wider toward the side closer to the tail cylinder, that is, has a larger cross-sectional diameter perpendicular to the central axis. The trumpet bus is preferably a straight line.

  A bypass 6 for taking in bypass air is attached to the combustion cylinder 2. An acoustic box 5 is installed on the outer wall of the combustion cylinder 2. In FIG. 1, the acoustic box 5 has a belt-like shape that surrounds the entire circumference of the combustion cylinder 2 in the circumferential direction, but is not limited to this shape, and may have other shapes.

  Referring to FIG. 2, a cross-sectional view of the vicinity of the combustion cylinder 2 of the combustor 1 is shown. A space inside the combustion cylinder 2 is a combustion region 8. The combustion region 8 has no step (discontinuous change in the shape of the wall surface).

  A substantially cylindrical nozzle holding cylinder 13 is connected to the upstream side of the combustion cylinder 2 via an outer ring structure A. A pilot nozzle 12 is installed on the central axis of the nozzle holding cylinder 13. A plurality of main nozzles 14 are installed on a predetermined radius from the central axis of the nozzle holding cylinder 13 so as to surround the pilot nozzle 12.

  The pilot nozzle 12 and the plurality of main nozzles 14 can eject natural gas. The pilot nozzle 12 and the plurality of main nozzles 14 can eject oil fuel when the operator switches the operation mode.

  An extension pipe 15 is provided on the downstream side of the main nozzle 14 for once restricting the flow of fuel and air. When there is no extension pipe, the fuel and air are discharged into a wide space before being sufficiently mixed, and thus combustion occurs in an insufficiently mixed state, resulting in insufficient NOx reduction. Further, since a low flow velocity region exists and a portion having a high fuel concentration is formed, backfire (flashback, a phenomenon in which the flame on the downstream side burns into the flame remaining on the upstream side) is likely to occur.

  The extension pipe is to secure the axial distance of the area where fuel and air are mixed, and since the flow velocity is not reduced, the possibility of flashback is reduced and the fuel and air are mixed sufficiently. A premixed gas mixture is generated. Since the temperature of the wall surface from the downstream end portion of the extension pipe to the downstream side is extremely high up to 400 mm, cooling is particularly necessary.

  An exit throttle 17 is installed near the downstream end of the combustion cylinder 2. A tail cylinder 3 is connected to the downstream side of the combustion cylinder 2. The outlet throttle 17 is attached to the inner wall of the combustion cylinder 2 and protrudes toward the center of the combustion region 8. The outlet throttle 17 mixes cold air such as film air near the wall surface with hot gas at the center of the combustor. If the cold air such as film air near the wall surface and the high temperature gas at the center of the combustor flow into the turbine section without mixing, the reliability of the turbine is lowered. Useful for improvement.

  A number of sound absorbing holes 16 are provided in the wall surface of the combustion cylinder 2 in the region where the acoustic box 5 is installed. The combustion area 8 and the inside of the acoustic box 5 communicate with each other through the sound absorbing holes 16. The acoustic box 5 and the sound absorption holes 16 are collectively referred to as an acoustic liner. The aperture ratio of the sound absorbing holes 16 changes in the circumferential direction of the combustion cylinder 2. A portion of the combustion cylinder 2 that is close to the downstream of the main nozzle 14 is hot, and a portion that is away from the main nozzle in the circumferential direction is relatively cold. The sound absorbing hole 16 has a large opening ratio at a portion that is located downstream of the main nozzle and becomes high temperature, and has a small opening ratio at a portion that is away from the main nozzle in the circumferential direction. Or the sound absorption hole 16 is not provided in the part which the angle of the circumferential direction of the combustion cylinder 2 is more than the predetermined angle from the extension line which extended the main nozzle downstream.

  Referring to FIG. 3, the structure near the outer ring structure A is shown. In the vicinity of the outer ring structure A, the combustion cylinder 2 is connected to the downstream end of the nozzle holding cylinder mounting portion 19 at the upstream end. The nozzle holding cylinder mounting portion 19 (the wall facing the vehicle compartment 4) is bent in the direction of increasing the diameter near the nozzle holding cylinder 13 and is connected to the downstream end of the nozzle holding cylinder 13.

  There is an extension pipe outer space 20 on the inner peripheral side of the nozzle holding cylinder mounting portion 19 and on the outer peripheral side of the extension pipe 15. The nozzle holding cylinder mounting portion 19 is provided with a cooling air hole 22 for taking cooling air into the extension pipe outer space 20. A gap 24 is provided between the downstream end of the extension pipe 15 and the nozzle holding cylinder mounting portion 19.

  An outer ring 18 is provided continuously over the entire inner circumference of the combustion cylinder 2 in the combustion cylinder 2 at a position corresponding to the downstream end of the extension pipe 15. That is, the outer ring 18 has a rotationally symmetric shape around the central axis of the combustion cylinder 2.

  The outer ring 18 includes a guide 23. The guide 23 is also provided continuously over the entire inner circumference of the combustion cylinder 2. That is, it has a rotationally symmetrical shape around the central axis of the combustion cylinder 2. The space formed by the outer ring 18 and the guide is hereinafter referred to as the guide space 28.

  An intake hole 27 for introducing cooling air from the vehicle compartment 4 to the guide space 28 is provided in the wall of the combustion cylinder 2 corresponding to the position where the guide 23 is provided. The downstream end of the guide space 28 is open, and the opening is hereinafter referred to as a spout 29.

  The distance from the intake hole 27 to the jet outlet 29 is sufficiently small. Therefore, the cooling air ejected from the ejection port 29 has a dynamic pressure due to the flow of the cooling air flowing along the guide 23. In other words, the guide 23 changes the momentum in the inner peripheral direction of the combustion cylinder 2 when the cooling air is introduced from the intake hole 27 into the guide space 28 to the momentum in the downstream direction of the combustion cylinder 2, and Cooling air is ejected from the downstream.

  As a result, the dynamic pressure contribution obtained is greater than the static pressure contribution due to the difference between the pressure in the guide space 28 and the pressure in the combustion region 8. That is, a substantial portion of the kinetic energy of the flow of cooling air ejected from the guide space 28 to the combustion region 8 via the ejection port 29 is the motion of the cooling air flow when blown from the vehicle compartment 4 via the intake hole 27. Supplied by energy.

  Referring to FIG. 4, the flow of cooling air near the jet outlet 29 is shown. A part of the cooling air blown from the intake hole 27 collides with the wall surface of the guide 23 and changes its direction, and goes to the jet outlet 29. Since the distance from the suction hole 27 to the jet outlet 29 is short, the dynamic pressure of the air passing through the suction hole 27 is effectively used for forming film air. The other part of the cooling air blown from the intake hole 27 collides with the wall surface of the guide 23 and changes its direction to once flow in the direction opposite to the ejection port 29, and then is guided by the guide 23 and the outer ring 18. It collides with the inner wall of the space to be formed, the direction of the flow is reversed, and it heads toward the jet outlet 29. In this case, the distance from the intake hole 27 to the jet outlet 29 is also preferably short so that the dynamic pressure of the air passing through the intake hole 27 is effectively used for forming film air. Thereby, since film air can be ejected at a high speed in the direction of the main flow in the inside of the combustion cylinder 2, the entrainment of the backflow is prevented and high film efficiency is achieved. In order to achieve high film efficiency, it is preferable that there is no supporting member or the like in the flow path between the intake hole 27 and the ejection port 29. If there is a supporting member, the flow velocity is lowered on the downstream side, and there is a possibility that a reverse flow is involved.

  The structure of the guide 23, the intake hole 27, the guide space 28, and the jet port 29 shown in FIG. 4 can be provided also in other portions of the combustion cylinder that are particularly desired to be cooled. Even in that case, the cooling by the structure shown in FIG. 4 can be performed without forming a place where the oil fuel is accumulated.

  Referring to FIG. 5, the basic structure of the plate forming the wall surface of the combustion cylinder 2 is shown by a broken perspective view. The combustion cylinder 2 is formed by integrally joining an inner wall 36 facing the combustion region 8 and an outer wall 37 facing the vehicle compartment 4. A large number of grooves 36 a through which cooling air or water vapor passes are provided between the inner wall 36 and the outer wall 37. The groove 36a faces in a direction substantially parallel to the trumpet bus. The outer wall 37 is provided with an inlet 37a. The vehicle compartment 4 and the groove 36 a communicate with each other through an entrance 37. The inner wall 36 is provided with an outlet 37b. The combustion region 8 and the groove 36a communicate with each other through an outlet 37b.

  The positions of the groove 36 a, the inlet 37 a, and the outlet 37 b slightly change according to the structure provided in the combustion cylinder 2. The change is shown in FIGS. 6 (a) and 6 (b).

  6A and 6B, the arrangement of cooling grooves in the vicinity where the acoustic box 5 is provided is shown. FIG. 6A is a cross-sectional view of a wall surface of the combustion cylinder 2 cut along a plane including the central axis of the combustion cylinder 2, and the right side is the downstream side. FIG. 6B is a cross-sectional view in which the wall surface is cut parallel to the direction in which the wall surface of the combustion cylinder 2 extends, and the right side corresponds to the downstream side corresponding to the position in FIG.

  An acoustic liner cooling groove 45 is provided in a region of the wall surface of the combustion cylinder 2 where the acoustic liner is formed by the acoustic box 5 and the sound absorbing holes 16. The acoustic liner cooling groove 45 corresponds to the groove 36a in FIG. The acoustic liner cooling groove 45 is provided so as to avoid the position where the sound absorbing hole 16 is provided, that is, so as not to communicate with the sound absorbing hole 16. The acoustic liner cooling groove 45 communicates with the vehicle compartment 4 via an inlet 42 provided on the outer wall on the upstream side of the acoustic liner. The inlet 42 corresponds to the inlet 37a in FIG. The acoustic liner cooling groove 45 extends to the downstream side of the acoustic liner.

  A cooling groove 46 is provided in parallel with the acoustic liner cooling groove 45 on the downstream side of the acoustic liner in the wall surface of the combustion cylinder 2. The cooling groove 46 corresponds to the groove 36a in FIG. The cooling groove 46 is provided at a position where the sound absorbing hole 16 is located on the extension line on the upstream side. The upstream end of the cooling groove 46 communicates with the vehicle compartment 4 via an inlet 42 a provided on the outer wall slightly downstream of the acoustic box 5.

  Among the acoustic liner cooling groove 45 and the cooling groove 46, a groove having an obstacle such as a welded portion of the outlet throttle 17, the spring clip, or the buggy clip on the downstream extension line has a downstream end from the outlet throttle 17. Further, it communicates with the passenger compartment 4 through an outlet 44 provided on the outer wall slightly upstream.

  Of the acoustic liner cooling groove 45 and the cooling groove 46, the outlet end surface cooling groove 47, which is a groove that does not have the outlet 44, extends further downstream than the outlet 44. The outlet end surface cooling groove 47 passes through the vicinity of the outlet throttle 17, the spring clip, or the welded portion of the buggy clip, and communicates with the combustion region 8 at the downstream end of the combustion cylinder 2.

  The outlet 44 for performing convection cooling and film cooling by the acoustic liner cooling groove 45 and the cooling groove 46 shown in FIGS. 6A and 6B is within 400 mm from the downstream end of the extension pipe as described above. Since it becomes high temperature, it is provided within 400 mm downstream from the outlet of the extension pipe. In a part further away from the main nozzle 14, it is preferable that no cooling air is used or only a small amount is used.

A drain hole 49 is provided on the wall surface of the acoustic box 5. When oil is used as the fuel, the oil that has entered the inside of the acoustic box 5 is discharged from the drain hole 49 and therefore does not accumulate inside the acoustic box 5. Note that a plurality of combustion cylinders 2 including the acoustic box 5 are installed in the circumferential direction of the gas turbine. However, the drain hole 49 is configured so that the combustion cylinder 2 is a gas so that oil is discharged at any position. When installed in the turbine, it is formed so as to be positioned below the acoustic box 5. Alternatively, a plurality of drain holes 49 are provided in the acoustic box 5, and any one of the plurality of drain holes 49 is formed in the lower part of the acoustic box 5, no matter where the acoustic box is installed in the circumferential direction of the gas turbine. It is formed to be located.

  The combustor having the above configuration operates as follows.

  When the gas turbine plant including the combustor 1 is started, compressed air discharged from a compressor (not shown) is sent into the vehicle compartment 4. The compressed air is further fed from the passenger compartment 4 to the combustor 1.

  The air sent to the combustor 1 is mixed with fuel injected from the pilot nozzle 12 and ignited, and a flame is generated downstream of the pilot nozzle 12. The fuel blown from the main nozzle 14 is ignited by the flame of the pilot nozzle 12, and a flame is generated downstream of each main nozzle 14. The combustion region 8 is filled with hot combustion gas. The combustion gas is introduced into a turbine (not shown) connected to the downstream side via the transition piece 3.

  Combustion vibration is generated in the combustion cylinder 2. Combustion vibration having a frequency unique to the combustion cylinder 2 resonates in the acoustic box 5 and is attenuated by the sound absorption hole 16. As a result, combustion vibration is reduced.

  Since the combustion cylinder 2 has a trumpet shape in which the diameter continuously increases, the combustion gas flow is prevented from stagnation (a region where the flow velocity is lower than the surroundings). For this reason, a phenomenon in which oil accumulates in the stagnation during oil burning operation (an operation state in which oil is injected and burned from the pilot nozzle 12 and the main nozzle 14) is prevented.

  When oil fuel adheres to the vicinity of the jet outlet 29, the cooling air blown out from the jet outlet 29 has a dynamic pressure toward the downstream side, so that the oil fuel is blown away. The jet port 29 is opened over the entire circumference of the outer ring 21 and there is no obstacle such as a spacer that prevents the cooling air from being jetted, so that oil fuel is prevented from accumulating in the vicinity of the jet port 29.

  Since the cooling air ejected from the ejection port 29 greatly contributes to the dynamic pressure, it flows near the inner wall of the combustion cylinder 2 with a strong force. Therefore, it is less affected by the pressure distribution near the inner wall of the combustion cylinder 2 on the downstream side of the jet port 29, and the inner wall is cooled uniformly.

  The compressed air in the passenger compartment 4 is blown into the extension pipe outer space 20 from the cooling air hole 22 due to a pressure difference. The cooling air blown in is blown out toward the combustion region 8 through the gap 24 and used for film cooling.

  The inner wall of the combustion cylinder 2 is film-cooled by the air ejected from the ejection port 29 and the air ejected from the gap 24. Film concentration reduces the concentration of fuel in the vicinity of the inner wall. As a result, combustion is prevented even in the vicinity of the inner wall, and a phenomenon in which the flame returns from the downstream side to the upstream side is prevented. Therefore, the wall surface of the outer ring is prevented from being overheated and the combustion is prevented from becoming uneven. Further, since the flame extending from the main nozzle 14 becomes a long flame in the downstream direction, the premixed gas is mixed in the combustor and NOx is lowered. Furthermore, since the heat becomes uniform and does not concentrate, the vibration in the axial direction is suppressed. Further, since the amount of heat generated in the vicinity of the wall surface is small, vibration combustion in the circumferential mode is suppressed.

  The air in the passenger compartment 4 flows into the acoustic liner cooling groove 45 from the inlet 42. The wall surface of the portion where the sound absorbing hole 16 is opened is also cooled by the cooling air flowing through the acoustic liner cooling groove 45.

  The air in the passenger compartment 4 flows into the cooling groove 46 from the inlet 42a. On the downstream side of the acoustic liner, the wall surface is effectively cooled by the acoustic liner cooling groove 45 and the cooling groove 46.

  A part of the cooling air flowing through the acoustic liner cooling groove 45 and the cooling air flowing through the cooling groove 46 is jetted from the outlet 44 toward the combustion region 8 to cool the inner wall with a film. Since the outlet 44 of this shape does not have a low flow velocity region in the vicinity of the jet outlet for cooling the film, oil is prevented from adhering and accumulating when the combustor 1 is operated by oiling.

  The air jetted from the outlet 44 cools the inner wall of the combustion cylinder 2 and the inner wall of the tail cylinder 3 with film. Film concentration reduces the concentration of fuel in the vicinity of the inner wall. As a result, combustion is prevented even in the vicinity of the inner wall, and a phenomenon in which the flame returns from the downstream side to the upstream side is prevented. Therefore, the wall surface of the outer ring is prevented from being overheated and the combustion is prevented from becoming uneven. Further, since the flame extending from the main nozzle 14 becomes a long flame in the downstream direction, the premixed gas is mixed in the combustor and NOx is lowered. Furthermore, since the heat becomes uniform and does not concentrate, the vibration in the axial direction is suppressed. Further, since the amount of heat generated in the vicinity of the wall surface is small, vibration combustion in the circumferential mode is suppressed.

  The outlet 44 is provided immediately before the outlet throttle 17. Although the outlet throttle 17 is a component installed in the gas path, it is difficult to cool the outlet throttle 17, but the metal temperature of the outlet throttle 17 is lowered by the film cooling by the cooling air ejected from the outlet 44, thereby extending the life.

  The outlet end surface cooling groove 47 cools the wall surface downstream of the outlet throttle 17. Therefore, the wall surface on which the outlet throttle 17, the spring clip, the buggy clip welded portion, and the like are also cooled, the metal temperature of the portion is lowered, and the life is extended.

  In the part which is separated from the main nozzle 14 by 400 mm or more on the downstream side, the cooling air is not used at all or only a small amount is not used. Therefore, more air can be used for combustion, and NOx is reduced.

  According to such a combustor 1, the wall surface temperature of a combustion cylinder and a tail cylinder is kept low, and lifetime is extended. Furthermore, since the flame becomes a long flame, NOx can be reduced and vibration combustion can be prevented from occurring.

FIG. 1 shows a gas turbine combustor. FIG. 2 shows a cross-sectional view of the combustion cylinder. FIG. 3 is a cross-sectional view showing the outer ring structure. FIG. 4 shows the cooling gas flow in the outer ring space. FIG. 5 is a cutaway perspective view showing the structure of the wall surface of the combustion cylinder. FIG. 6 is a side view and a top view showing the arrangement of the cooling grooves.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Combustor 2 ... Combustion cylinder 3 ... Tail cylinder 4 ... Cabin 5: Acoustic box 6 ... Bypass 8 ... Combustion area 12 ... Pilot nozzle 13 ... Nozzle holding cylinder 14 ... Main nozzle 15 ... Extension pipe 16 ... Sound absorption hole 17 ... Outlet throttle 18 ... Outer ring 19 ... Nozzle holding cylinder mounting portion 20 ... Extension pipe outer space 21 ... Outer ring 22 ... Cooling air hole 24 ... Gap 27 ... Intake hole 28 ... Guide space 29 ... Jet outlet 36 ... Inner wall 37 ... Outer wall 36a ... groove 37a ... inlet 37b ... outlet 42, 42a ... inlet 44 ... outlet 45 ... acoustic liner cooling groove 46 ... cooling groove 47 ... outlet end face cooling groove 49 ... drain hole

Claims (6)

A combustion cylinder forming a combustion region therein;
An acoustic box installed in a predetermined area outside the combustion cylinder;
A nozzle for injecting combustion oil into the combustion region;
The acoustic box has a drain hole for discharging oil. Gas turbine combustor. A gas turbine combustor according to claim 1, comprising:
The combustion cylinder has a cooling groove through which a coolant flows between an inner wall surface facing the combustion region and an outer wall surface facing the outside of the combustion cylinder,
The combustion cylinder is provided with a plurality of sound absorption holes that connect the inside of the acoustic box and the combustion region in the predetermined region,
The cooling groove is
A first cooling groove provided not to communicate with the sound absorption hole in the predetermined region;
A gas turbine combustor including a second cooling groove provided in a region other than the predetermined region. A gas turbine combustor according to claim 2, comprising:
The sound absorption hole has a large opening ratio in a portion close to an extended line obtained by extending a nozzle for injecting fuel into the combustion region on the downstream side. A gas turbine combustor according to claim 2 or 3,
Of the predetermined region, a portion that is separated from the central axis of the combustion cylinder by a predetermined angle or more in the circumferential direction of the combustion cylinder from an extension line extending downstream of a nozzle that injects fuel into the combustion area Is a gas turbine combustor in which the sound absorption hole is not provided. A gas turbine combustor according to any one of claims 1-4,
The drain hole is provided at the lowest position in the vertical direction of the acoustic box when the drain hole is installed in a state where the gas turbine combustor is operated. A gas turbine combustor according to any one of claims 1-4,
A plurality of the drain holes are provided,
When the gas turbine combustor is installed in a state where the gas turbine combustor is operated, all of the acoustic boxes installed in the combustion cylinder are at the lowest position in the vertical direction of any of the plurality of drain holes. Gas turbine combustor.

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