Combustor for gas turbine

Abstract

To suppress an increase in weight of a combustor, successfully enable a laminar flow of cooling air ejecting from a cooling hole to a combustion chamber and effectively cool a liner of the combustor.SOLUTION: A combustor for a gas turbine comprises: a first cooling hole 128 formed to penetrate through a connection part 126 of a liner 100 defining a combustion chamber 46; a thick wall part 130 provided at a portion of the connection part 126 located in the vicinity of the first cooling hole 128 in the radial direction; a wind guide part 132 extending in the flowing direction of combustion gas from the thick wall part 130 beyond an outlet of the first cooling hole 128 along an inner surface of the connection part 126 of the liner 100; and a second cooling hole 136 formed to penetrate through the thick wall part 130.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a combustor for a gas turbine. [Background technology]

[0002] As a combustor for generating combustion gas in a gas turbine engine, an annular combustor is known, which defines a donut-shaped combustion chamber around a central axis and has a liner (housing) to which a fuel injection nozzle is attached at one end in the axial direction (for example, Patent Document 1).

[0003] In such a combustor, cooling holes are provided that penetrate the wall of the liner, and the cooling air ejected from the cooling holes into the combustion chamber flows along the wall surface of the liner on the combustion chamber side, thereby enabling the liner to be cooled effectively. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-150796 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to effectively cool the liner with the cooling air ejected from the cooling holes into the combustion chamber, it is preferable that the cooling air flows in a layer along the wall surface of the liner on the combustion chamber side.

[0006] If the cooling air ejected from the cooling holes into the combustion chamber has a high flow velocity and a large turbulent component, the cooling air tends to separate from the liner wall, hindering cooling of the liner wall. Therefore, it is preferable to reduce the flow velocity of the cooling air as much as possible as it flows through the cooling holes. To achieve this, it is preferable to gradually increase the area of the cooling hole outlet relative to the cooling hole inlet, thereby promoting the deceleration of the cooling air flowing through the cooling holes. This allows the liner to be cooled effectively by the cooling air.

[0007] However, in order to effectively decelerate the cooling air in the cooling holes provided in the liner, it is necessary to increase the passage length of the cooling holes, which increases the wall thickness of the liner, i.e., the weight of the combustor, hindering weight reduction of the gas turbine engine.

[0008] In view of the above background, an object of the present invention is to suppress an increase in the weight of a combustor, to effectively decelerate the cooling air (cooling air flow) ejected from cooling holes into a combustion chamber, and to effectively cool the liner of the combustor.

[0009] In order to solve the above-mentioned problems, one aspect of the present invention is a combustor (18) for a gas turbine (18) for generating combustion gas, which is arranged in a cooling air chamber (44) of a gas turbine engine (10), and which has a liner (100) that defines a combustion chamber (46) around a predetermined axis, and the liner has first cooling holes (128) formed through a wall (126) of the liner, a thick portion (130) provided in a portion of the wall located radially near the first cooling holes, an air guidance portion (132) extending from the thick portion along the inner surface of the wall of the liner in the flow direction of the combustion gas beyond the outlet of the first cooling hole, and a second cooling hole (136) formed through the thick portion.

[0010] According to this aspect, an increase in the weight of the combustor is suppressed, and since the passage length of the second cooling hole is increased, it is possible to widen the downstream portion, and the cooling air ejected from the second cooling hole toward the combustion chamber is decelerated well. In this case, the combustor may be an annular type or a can type.

[0011] In the above aspect, the second cooling hole may have a passage shape that includes a portion (136B) that widens from the cooling air chamber side toward the combustion chamber side.

[0012] According to this aspect, the cooling air ejected from the second cooling holes into the combustion chamber is effectively decelerated, and the liner is effectively cooled.

[0013] In the above aspect, the second cooling hole may include an upstream portion (136A) having a substantially constant inner diameter, and a downstream portion (136B) that widens from the cooling air chamber side toward the combustion chamber side.

[0014] According to this aspect, when the cooling air ejected from the second cooling hole into the combustion chamber is effectively decelerated, the cooling air flowing along the wall surface of the combustion chamber is less likely to separate from the wall surface, and the liner is cooled effectively.

[0015] In the above aspect, the downstream portion of the second cooling hole may have a cross-sectional shape that is long in the radial direction.

[0016] According to this aspect, the cooling air flowing along the wall surface of the combustion chamber is less likely to separate from the wall surface, and the liner is cooled effectively.

[0017] In the above aspect, the second cooling holes may be inclined in the circumferential direction.

[0018] According to this aspect, the passage length of the second cooling hole is increased, which allows the downstream portion to be widened, and the cooling air ejected from the second cooling hole into the combustion chamber is more effectively decelerated.

[0019] In the above aspect, the wall of the liner may include an end wall (102) that is substantially perpendicular to the axial direction and a peripheral wall (104, 106) that extends in the axial direction so as to be continuous with the end wall, and the first cooling hole and the second cooling hole may be provided at a connection portion (126) between the end wall and the peripheral wall.

[0020] According to this aspect, the connection between the end wall and the peripheral wall is effectively cooled.

[0021] In the above aspect, the airflow guidance portion may extend in a direction to guide the cooling air from the end wall side toward the peripheral wall side.

[0022] According to this aspect, the peripheral wall is cooled effectively. [Effects of the Invention]

[0023] According to the above aspect, an increase in the weight of the combustor is suppressed, the cooling air ejected from the cooling holes into the combustion chamber is decelerated well, and the liner of the combustor is effectively cooled. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a longitudinal cross-sectional view showing a power-generating gas turbine engine to which a gas turbine combustor according to the present invention is applied. [Figure 2] FIG. 1 is a vertical cross-sectional perspective view showing a portion of a preferred embodiment of a combustor for a gas turbine according to the present embodiment. [Figure 3] FIG. 1 is an enlarged perspective view of an end wall and a connecting portion of a combustor for a gas turbine according to an embodiment of the present invention, as viewed from the combustion chamber side. [Figure 4] FIG. 1 is an enlarged, partially sectional perspective view of a main portion of a gas turbine combustor according to an embodiment of the present invention; [Figure 5] FIG. 1 is an enlarged vertical cross-sectional view of a main portion of a gas turbine combustor according to an embodiment of the present invention. [Figure 6] FIG. 10 is an enlarged vertical cross-sectional view of a main portion of a gas turbine combustor according to another embodiment. [Figure 7] FIG. 10 is a vertical cross-sectional perspective view showing a portion of a combustor for a gas turbine according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] Fig. 1 is a cross-sectional view of a power-generating gas turbine system 10 to which a gas turbine combustor according to this embodiment is applied. As shown in Fig. 1, the power-generating gas turbine system 10 has a radial compressor 14 and a radial turbine 16 that are coaxially connected to each other by a rotating shaft 12. An input shaft of a generator 20 is connected to the rotating shaft 12.

[0026] The power generating gas turbine system 10 includes a front end plate 22 located on the side of the generator 20, a front housing 24, a middle housing 26, and a rear housing 28, arranged in this order in the axial direction.

[0027] The radial compressor 14 has a compressor liner 32 attached to the front housing 24 and defining a compressor chamber 30, a diffuser fixing member 36 that fixes a diffuser 34, and an air intake guide member 38 attached to the front end plate 22. The air intake guide member 38 cooperates with the compressor liner 32 to define an air intake port 40. A compressor rotor 42 attached to the rotary shaft 12 is rotatably disposed in the compressor chamber 30. The compressor rotor 42 is rotationally driven by the rotary shaft 12, which is the output shaft of the radial turbine 16.

[0028] The radial compressor 14 takes in air (outside air) from an air intake 40, compresses and pressurizes the air by the rotation of a compressor rotor 42, and ejects the compressed and pressurized air (cooled air) into the diffuser 34.

[0029] The combustor 18 is disposed within the rear housing 28 and arranged around the central axis of the rotary shaft 12. The rear housing 28 includes a portion that defines a compressed air chamber 44 that directs cooling air from the diffuser 34 to the combustor 18. The combustor 18 defines a combustion chamber 46. Fuel injection nozzles 48 are attached to various portions of the combustor 18. The fuel injection nozzles 48 inject fuel into the combustion chamber 46.

[0030] In the combustion chamber 46, a mixture of fuel injected into the combustion chamber 46 by a fuel injection nozzle 48 and cooling air from the radial compressor 14 is combusted, generating high-temperature combustion gas (compressed fluid). A turbine nozzle 50 is provided at the combustion gas outlet 112 of the combustor 18.

[0031] The radial turbine 16 has a turbine chamber 52 that is defined by the inner portion of the rear housing 28 and communicates with the combustion gas outlet 112 of the combustor 18. The turbine chamber 52 is separated from the compressor chamber 30 by a partition member 54. The side of the turbine chamber 52 that is away from the partition member 54 is defined by a shroud 56. A radial turbine impeller 58 that is integrally formed with the rotary shaft 12 is rotatably disposed in the turbine chamber 52.

[0032] The turbine nozzle 50 is annular in shape so as to surround the radial turbine impeller 58, and injects combustion gas radially inward and circumferentially toward the radial turbine impeller 58. The radial turbine impeller 58 is rotationally driven by the combustion gas injected from the turbine nozzle 50. The combustion gas that has rotationally driven the radial turbine impeller 58 is discharged as exhaust gas into the atmosphere from an exhaust gas passage 60 defined by a tubular member connected to the rear end of the rear housing 28.

[0033] A rotor shaft 62 of the generator 20 is connected to the rotary shaft 12. As a result, the generator 20 is rotationally driven by the rotary shaft 12 of the radial turbine 16 to generate electricity.

[0034] The combustor 18 will be described in detail with reference to FIGS.

[0035] The combustor 18 is an annular combustor and, as shown in Fig. 1, has a liner (housing) 100 arranged approximately concentrically within the cylindrical compressed air chamber 44. As shown in Fig. 2, the liner 100 includes an annular end wall 102 extending in a direction approximately perpendicular to the axial direction, an outer peripheral wall 104 extending in the axial direction and having a substantially cylindrical shape, the outer peripheral wall 104 being connected to the outer peripheral edge of the end wall 102 at a first end 104A so as to be continuous with the outer peripheral edge of the end wall 102, and an inner peripheral wall 106 also extending in the axial direction and having a substantially cylindrical shape, the inner peripheral wall 106 being connected to the inner peripheral edge of the end wall 102 at a first end 106A so as to be continuous with the inner peripheral edge of the end wall 102, thereby defining the donut-shaped combustion chamber 46 around the central axis.

[0036] The liner 100 is manufactured by, for example, an additive manufacturing (AM) method in which metal is layered from bottom to top with the end wall 102 facing downward and the central axis of the liner 100 extending vertically. In this embodiment, the liner 100 is formed as a single unit by layering, but it is also possible to form the outer peripheral wall 104, the inner peripheral wall 106, and the end wall 102 separately and then join the respective parts together.

[0037] The outer surface of the liner 100 is exposed to the flow of cooling air from the compressed air chamber 44 and is cooled using the cooling air as a cooling medium.

[0038] Mounting portions 110 for the fuel injection nozzles 48 are formed at predetermined intervals in the circumferential direction on the end wall 102. Each fuel injection nozzle 48 mixes air and fuel from the compressed air chamber 44 and injects the resulting mixture into the combustion chamber 46. In the combustion chamber 46, the mixture combusts, generating high-temperature combustion gases.

[0039] The outer peripheral wall 104 and the inner peripheral wall 106 have first ends 104A, 106A that are continuous with the end wall 102, and second ends 104B, 106B that are opposite in the axial direction to the first ends 104A, 106A. These second ends 104B, 106B cooperate with each other to define an annular combustion gas outlet 112 that opens radially inward. The combustion gas outlet 112 is connected to the turbine nozzle 50 (see FIG. 1) of the radial turbine 16 to supply fuel gas to the radial turbine 16.

[0040] The combustion gases flow through the combustion chamber 46 in a flow direction F indicated by the arrows in FIG. 2 from the end wall 102 toward the combustion gas outlet 112 .

[0041] Each of the outer peripheral wall 104 and the inner peripheral wall 106 has a plurality of upright wall portions 114 extending circumferentially and spaced apart at predetermined intervals in the axial direction, and an inclined wall portion 116 extending between adjacent upright wall portions 114 in the axial direction and continuing to the corresponding upright wall portion 114. In detail, as shown in Fig. 2, each inclined wall portion 116 extends in an annular shape around the central axis between an outer edge portion 114A (side away from the combustion chamber 46) in the radial direction of the adjacent upright wall portion 114 on the upstream side with respect to the flow direction F of the combustion gas, and an inner edge portion 114B (side close to the combustion chamber 46) in the radial direction of the adjacent upright wall portion 114 on the downstream side.

[0042] A plurality of cooling holes 120 are formed at predetermined intervals in the circumferential direction in each of the upright wall portions 114. A plurality of cooling holes 108 are formed in the end wall 102. Compressed air from the compressed air chamber 44 is supplied to each of the cooling holes 108, 120 as cooling air.

[0043] The outer peripheral edge of the end wall 102 and a first end 104A of the outer peripheral wall 104, and the inner peripheral edge of the end wall 102 and a first end 106A of the inner peripheral wall 106 are smoothly connected to each other by connecting portions 126 formed in the shape of a gentle arc. As shown in FIGS. 2 to 5, a plurality of first cooling holes 128 are formed through each connecting portion 126 at predetermined intervals in the circumferential direction. Each first cooling hole 128 extends substantially along the axial direction and has an inlet 128A that opens toward the compressed air chamber 44 and an outlet 128B that opens toward the combustion chamber 46.

[0044] A thickened portion 130 extending annularly along the circumferential direction is formed in a portion of the end wall 102 located radially near the first cooling hole 128. In other words, annular thickened portions 130 are formed near the outer peripheral edge and the inner peripheral edge of the end wall 102, along these edges. More specifically, the thickened portion 130 on the outer peripheral edge side of the end wall 102, i.e., the thickened portion 130 provided at the connection portion 126 between the end wall 102 and the outer circumferential wall 104, is provided in a position close to the direct inner side in the radial direction of the first cooling hole 128. The thickened portion 130 on the inner peripheral edge side of the end wall 102, i.e., the thickened portion 130 provided at the connection portion 126 between the end wall 102 and the inner circumferential wall 106, is provided in a position close to the direct outer side in the radial direction of the first cooling hole 128.

[0045] Each thick portion 130 bulges outward in a rounded manner toward the combustion chamber 46. An eave-shaped air guide portion 132 extends radially from the top of each thick portion 130 on the combustion chamber 46 side. More specifically, the air guide portion 132 on the outer peripheral edge side of the end wall 102 extends from the top of the corresponding thick portion 130 toward the outer peripheral wall 104, that is, radially outward. The air guide portion 132 on the inner peripheral edge side of the end wall 102 extends from the top of the corresponding thick portion 130 toward the inner peripheral wall 106, that is, radially inward.

[0046] Each airflow guidance section 132 is located within the combustion chamber 46 and extends radially beyond the opening of the corresponding first cooling hole 128 on the combustion chamber 46 side, i.e., beyond the outlet 128B. More specifically, the airflow guidance section 132 on the outer peripheral edge side of the end wall 102 extends radially outward beyond the outlet 128B of the first cooling hole 128. The airflow guidance section 132 on the inner peripheral edge side of the end wall 102 extends radially inward beyond the outlet 128B of the first cooling hole 128.

[0047] Each airflow guidance section 132 is located in a gently arcuate portion of the connecting section 126, and therefore has a shape that follows the shape of the connecting section 126. As a result, gaps 134 are formed at approximately regular intervals along the axial direction between the connecting section 126 and the airflow guidance section 132. The gaps 134 located on the outer peripheral edge side of the end wall 102 are open radially outward, and the gaps 134 located on the inner peripheral edge side of the end wall 102 are open radially inward, each in the shape of a circular slot.

[0048] A plurality of second cooling holes 136 are formed through each thick portion 130 at regular intervals in the circumferential direction. Each second cooling hole 136 is formed so as to be inclined in the circumferential direction at a predetermined angle relative to the axial direction. Each second cooling hole 136 has a passage shape including an upstream portion 136A on the compressed air chamber 44 side, which has a substantially constant inner diameter along the longitudinal direction of the second cooling hole 136, and a downstream portion 136B on the combustion chamber 46 side, which widens from the compressed air chamber 44 side toward the combustion chamber 46, thereby constituting a so-called shaped hole. The downstream portion 136B of each second cooling hole 136 has a cross-sectional shape that is long in the circumferential direction.

[0049] With this structure at the connection portion 126, the compressed air in the compressed air chamber 44 is ejected axially from the first cooling holes 128 into the gap 134 as cooling air. The cooling air ejected into the gap 134 is guided by the airflow guidance portion 132, changes direction to a radial flow, and flows from the end wall 102 side to the outer circumferential wall 104 and inner circumferential wall 106d side. Stratification of the cooling air is promoted while flowing through the gap 134, which forms a relatively long flow path, and the cooling air flows in layers from the gap 134 along the wall surface of the combustion chamber 46. This allows the connection portion 126 of the liner 100 to be suitably cooled and protected from the combustion gases.

[0050] The second cooling holes 136 are formed through the thick-walled portion 130, and therefore the passage length is longer by the thickness of the thick portion. This makes it possible to form a shaped hole without increasing the weight of the combustor 18, and the cooling air ejected from the second cooling holes 136 toward the combustion chamber 46 is decelerated effectively. The cooling air flows in layers in the circumferential direction along the inner surface of the connecting portion 126 of the liner 100 at the connecting portion 126. This allows the connecting portion 126 of the liner 100 to be suitably cooled and protected from the combustion gases.

[0051] Since the second cooling holes 136 are formed in the thick-walled portion 130 necessary for providing an air guidance section 132 within the combustion chamber 46, the passage length of the second cooling holes 136 is maximized without increasing the overall thickness of the liner 100, i.e., the overall thickness of the end wall 102, the outer peripheral wall 104, and the inner peripheral wall 106.

[0052] This allows the second cooling holes 136 to be configured as shaped holes suitable for obtaining laminar flow without increasing the overall thickness of the liner 100, and the liner 100 can be suitably protected against combustion gases.

[0053] The cooling air ejected from the second cooling holes 136 toward the combustion chamber 46 is decelerated and flows smoothly along the inner surface of the connecting portion 126, which has been prevented from peeling, because the downstream portion 136B of the second cooling holes 136 is widened toward the combustion chamber 46. This also ensures that the connecting portion 126 of the liner 100 is suitably cooled and protected from the combustion gases.

[0054] Because the downstream portion 136B of the second cooling hole 136 has a cross-sectional shape that is long in the circumferential direction, the cooling air flowing along the wall surface of the combustion chamber 46 is less likely to separate from the wall surface, and the liner 100 is cooled effectively.

[0055] The passage length of the second cooling holes 136 is also extended by being inclined in the circumferential direction, so that the second cooling holes 136 are suitable for being configured as shaped holes suitable for obtaining laminar flow.

[0056] The circumferential inclination directions of the second cooling holes 136 on the outer peripheral wall 104 side are opposite to those on the inner peripheral wall 106 side by 180 degrees. As a result, as shown in Figure 3, the second cooling holes 136 on the outer peripheral wall 104 side jet out cooling air in the counterclockwise direction, and the second cooling holes 136 on the inner peripheral wall 106 side jet out cooling air in the clockwise direction.

[0057] Although the specific embodiment has been described above, the present invention is not limited to the above embodiment and can be widely modified and implemented.

[0058] For example, in the above embodiment, the thick-walled portion 130 may bulge toward the compressed air chamber 44, as shown in Fig. 6. In this case, the wall surface of the combustion chamber 46 is not bulged by the thick-walled portion 130, and the wall surface is flush. Also, as shown in Fig. 7, the first cooling hole 128 may extend substantially radially of the combustion chamber 46, and the airflow guidance portion 132 may extend substantially axially of the thick-walled portion 130. In this case, the second cooling hole 136 constituting the shaped hole may pass through the thick-walled portion 130 and be inclined in the circumferential direction of the combustion chamber 46.

[0059] In the above embodiment, the airflow guidance section 132 extends in a direction to guide the cooling air from the end wall 102 side toward the outer peripheral wall 104 and inner peripheral wall 106 side, but it may also extend in a direction to guide the cooling air from the outer peripheral wall 104 and inner peripheral wall 106 side toward the end wall 102 side. The airflow guidance section 132 may also be provided on the end wall 102 or the outer peripheral wall 104 or inner peripheral wall 106.

[0060] The combustor 18 is not limited to an annular type, but may be a can type. Furthermore, the combustor 18 is not limited to a combustor for a gas turbine engine for power generation, but may be applied to combustors for various gas turbine engines, such as combustors for aircraft gas turbine engines. [Explanation of symbols]

[0061] 10: Gas turbine systems for power generation 18: Combustor 44: Compressed air chamber 46: Combustion chamber 100: Rina 102: End wall 104: Peripheral wall 104:Outer peripheral wall (peripheral wall) 104A: First end 104B: Second end 106:Inner peripheral wall (peripheral wall) 106A: 1st end 106B: Second end 108: Cooling hole 126: Connection part 128: 1st cooling hole 130: Thick wall part 132: Air guide section 136:Second cooling hole 136A: Upstream 136B: Downstream F: Flow direction

Claims

1. 1. A combustor for a gas turbine engine for generating combustion gases, the combustor being disposed in a cooling air chamber of the gas turbine engine, the combustor comprising: a liner defining a combustion chamber about a predetermined axis; The liner comprises: a first cooling hole formed through a wall of the liner; a thick portion provided in a portion of the wall located radially near the first cooling hole; an airflow guidance portion extending from the thick portion along the inner surface of the wall of the liner in the flow direction of the combustion gas beyond an outlet of the first cooling hole; a second cooling hole formed through the thick-wall portion.

2. 2. The combustor for a gas turbine according to claim 1, wherein the second cooling hole has a passage shape including a portion that widens from the cooling air chamber side toward the combustion chamber side.

3. 3. The combustor for a gas turbine according to claim 1, wherein the second cooling hole includes an upstream portion having a substantially constant inner diameter and a downstream portion expanding from the cooling air chamber side toward the combustion chamber side.

4. 4. The combustor for a gas turbine according to claim 3, wherein the downstream portion of the second cooling hole has a cross-sectional shape that is long in the circumferential direction.

5. 3. The gas turbine combustor according to claim 1, wherein the second cooling holes are inclined in the circumferential direction.

6. 3. The combustor for a gas turbine according to claim 1, wherein the wall of the liner includes an end wall substantially perpendicular to a direction of the axis and a peripheral wall extending in the direction of the axis so as to be continuous with the end wall, and the first cooling hole and the second cooling hole are provided at a connection portion between the end wall and the peripheral wall.

7. 7. The combustor for a gas turbine according to claim 6, wherein the airflow guidance portion extends in a direction to guide the cooling air from the end wall side toward the peripheral wall side.

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