GAS TURBINE COMBUSTOR

Abstract

This gas turbine combustor comprises: a combustion cylinder that defines a combustion chamber; a combustor for supplying fuel to the combustion chamber; and a two-stage combustion nozzle that is disposed, with respect to the combustor, on the downstream side in the flow direction of combustion gas in the combustion chamber. The two-stage combustion nozzle includes: a nozzle flow passage formation part that forms a nozzle flow passage having a nozzle injection port formed on the inner peripheral surface of the combustion cylinder; and a seal air flow passage formation part that forms a seal air flow passage having a seal air injection port at least a part of which is disposed, with respect to a nozzle central axis line being the center line of the two-stage combustion nozzle, on the upstream side in the flow direction of the combustion gas.

Description

TECHNICAL FIELD

The present disclosure relates to a gas turbine combustor that adopts a two-stage combustion method.

The present application claims priority based on Japanese Patent Application No. 2023-054802 filed in the Japan Patent Office on Mar. 30, 2023, the contents of which are incorporated herein by reference.

BACKGROUND ART

In the related art, a gas turbine combustor incorporated in a gas turbine is known. For example, a gas turbine combustor adopting a two-stage combustion method that is disclosed in PTL 1 includes a fuel nozzle as a second-stage nozzle. The fuel nozzle includes a premixed gas injection port that injects premixed gas and a cooling air injection port that injects compressed air as cooling air. Since the fuel nozzle is configured to protrude significantly into a combustion chamber of a combustion cylinder, the amount of heat transferred to the fuel nozzle from combustion gas generated in the combustion cylinder is large. The compressed air as the cooling air serves to suppress an excessive rise in the temperature of the fuel nozzle.

CITATION LIST

Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No. 2015-200493

SUMMARY OF INVENTION

Technical Problem

According to the inventors'findings, when a configuration in which a premixed gas injection port is disposed close to an inner peripheral surface of a combustion cylinder is applied to the fuel nozzle, there is a concern that a horseshoe vortex of combustion gas occurring on the inner peripheral surface will flow into the premixed gas injection port. In this case, flashback in which a flame is generated inside the fuel nozzle is likely to occur, and the fuel nozzle is likely to be burned.

An object of the present disclosure is to provide a gas turbine combustor that can suppress flashback.

Solution to Problem

According to at least one embodiment of the present disclosure, there is provided a gas turbine combustor including: a combustion cylinder that defines a combustion chamber; a combustor that supplies a fuel to the combustion chamber; and a two-stage combustion nozzle that is disposed on a downstream side of the combustor in a flow direction of a combustion gas in the combustion chamber, in which the two-stage combustion nozzle includes a nozzle flow path forming portion that forms a nozzle flow path having a nozzle injection port formed in an inner peripheral surface of the combustion cylinder and a seal air flow path forming portion that forms a seal air flow path having a seal air injection port at least a portion of which is disposed on an upstream side of a nozzle central axis, which is a center line of the two-stage combustion nozzle, in the flow direction of the combustion gas.

Advantageous Effects of Invention

According to the present disclosure, it is possible to provide a gas turbine combustor that can suppress flashback.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing a gas turbine according to an embodiment.

FIG. 2 is a schematic view showing a gas turbine combustor according to an embodiment.

FIG. 3A is a schematic view showing a two-stage combustion nozzle according to a first embodiment.

FIG. 3B is a schematic view showing a two-stage combustion nozzle according to a second embodiment.

FIG. 3C is a schematic view showing a two-stage combustion nozzle according to a third embodiment.

FIG. 4A is a schematic view showing a two-stage combustion nozzle to which a configuration according to a first example is applied.

FIG. 4B is a schematic view showing another two-stage combustion nozzle to which the configuration according to the first example is applied.

FIG. 4C is a schematic view showing still another two-stage combustion nozzle to which the configuration according to the first example is applied.

FIG. 5A is a schematic view showing a two-stage combustion nozzle to which a configuration according to a second example is applied.

FIG. 5B is a schematic view showing the two-stage combustion nozzle shown in FIG. 5A as viewed in an axial direction of a nozzle central axis C.

FIG. 5C is a cross-sectional view showing a partition wall taken along line A-A of FIG. 5A.

FIG. 6A is a schematic view showing a two-stage combustion nozzle to which a configuration according to a third example is applied.

FIG. 6B is a schematic view showing another two-stage combustion nozzle to which the configuration according to the third example is applied.

FIG. 7A is a schematic view showing a two-stage combustion nozzle to which a configuration according to a fourth example is applied (inner flow path wall is omitted).

FIG. 7B is a schematic view showing the two-stage combustion nozzle to which the configuration according to the fourth example is applied (a nozzle flow path wall one end portion is partially omitted).

FIG. 8A is a schematic view showing a two-stage combustion nozzle to which a configuration according to a fifth example is applied.

FIG. 8B is a schematic view showing an example of a more specific configuration of the two-stage combustion nozzle shown in FIG. 8A.

FIG. 8C is a schematic view showing another example of a more specific configuration of the two-stage combustion nozzle shown FIG. 8B.

FIG. 9 is a schematic view showing a two-stage combustion nozzle to which a configuration according to a sixth example is applied.

DESCRIPTION OF EMBODIMENTS

Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, dimensions, materials, shapes, relative dispositions, and the like of components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure and are only explanatory examples.

For example, it is assumed that, strictly speaking, an expression representing relative or absolute disposition, such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric”, or “coaxial”, not only represents the disposition, but also represents a state of relative displacement with a tolerance or a sufficient angle or distance to obtain the same function.

For example, it is assumed that, strictly speaking, expressions, such as “identical”, “equal”, and “homogeneous”, representing that things are in an equal state not only represent the equal state, but also represent a state in which there is a tolerance or a sufficient difference to obtain the same function.

For example, it is assumed that an expression representing a shape, such as a quadrangular shape or a cylindrical shape, not only represents a shape, such as a quadrangular shape or a cylindrical shape, in a geometrically strict sense, but also represents a shape including an uneven portion, a chamfered portion, or the like within a range in which the same effect is obtained.

Meanwhile, expressions such as “being provided with”, “including”, or “having” one component are not exclusive expressions excluding existence of other components. The same configurations are denoted by the same reference numerals, and the description thereof may be omitted.

1. Outline of Gas Turbine 100

FIG. 1 is a schematic view showing a gas turbine 100 according to an embodiment of the present disclosure. The gas turbine 100 includes a compressor 2 for generating compressed air, a gas turbine combustor 4 for generating combustion gas using the compressed air and fuel, and a turbine 6 configured to be driven by the combustion gas discharged from the gas turbine combustor 4. In the gas turbine 100 that may be, for example, a single-shaft gas turbine, the compressor 2 and the turbine 6 are connected by a rotary shaft 9, and a generator 5 is further connected to the rotary shaft 9.

In the gas turbine combustor 4, a mixed gas containing the compressed air sent from the compressor 2 and the fuel supplied from a fuel supply unit (not shown) is combusted to generate combustion gas as a working fluid for driving the turbine 6. The turbine 6 is driven by the combustion gas flowing into the turbine 6 to rotate the rotary shaft 9. As a result, the generator 5 generates power. In addition, examples of the fuel supplied to the gas turbine combustor 4 include hydrogen, methane, light oil, heavy oil, jet fuel, natural gas, gasified coal, and any combinations of two or more thereof. Hereinafter, the compressed air sent from the compressor 2 to the gas turbine combustor 4 may be referred to as “combustion air”.

2. Outline of Gas Turbine Combustor 4

FIG. 2 is a schematic view showing the gas turbine combustor 4 according to the embodiment of the present disclosure. The gas turbine combustor 4 includes a combustion cylinder 40 that defines a combustion chamber 47, a combustor 8 that is provided in one end portion of the combustion cylinder 40, and a two-stage combustion nozzle 20 that is provided on a cylindrical wall of the combustion cylinder 40. The combustor 8 is configured to inject the fuel and the combustion air along an axial direction of the combustion cylinder 40. A mixed gas generated by mixing the fuel injected from the combustor 8 and the combustion air is ignited to generate a flame inside the combustion chamber 47. The combustion gas as a main flow high-temperature gas generated in the combustion chamber 47 flows toward a downstream side (a right side in the example shown in FIG. 2). Hereinafter, a direction in which the combustion gas flows in the combustion chamber 47 may be referred to as a “combustion gas flow direction”. The two-stage combustion nozzle 20 is disposed on the downstream side of the combustor 8 in the combustion gas flow direction and is configured to inject the fuel and the combustion air along a radial direction of the combustion cylinder 40. The fuel and the combustion air are injected from the two-stage combustion nozzle 20 into the combustion chamber 47 such that second-stage combustion occurs in the combustion chamber 47. In the present example, a plurality of the two-stage combustion nozzles 20 are disposed at equal intervals along a circumferential direction of the combustion cylinder 40.

An example of the configuration of the combustor 8 is disclosed in Japanese Unexamined Patent Application Publication No. 2013-096303. A detailed description of the configuration will be omitted in this paper, and an outline thereof is as follows. The combustor 8 includes a pilot burner that is disposed at a center position of the combustion cylinder 40 and a plurality of main burners that are disposed at equal intervals to surround the pilot burner. The pilot burner includes a pilot nozzle that supplies pilot fuel and a tubular member that is provided to surround a tip portion of the pilot nozzle. A pilot air flow path is formed between the tubular member and the pilot nozzle, and the combustion air (pilot air) flows through the pilot air flow path. The main burner includes a main nozzle that supplies main fuel and a main air flow path that is formed around the main nozzle and supplies main air. The main fuel injected from the main nozzle is mixed with the main air supplied through the main air flow path to form a premixed gas.

3. Outline of Two-Stage Combustion Nozzle 20

FIGS. 3A, 3B, and 3C are schematic views showing a two-stage combustion nozzle 21 (20) according to a first embodiment, a two-stage combustion nozzle 22 (20) according to a second embodiment, and a two-stage combustion nozzle 23 (20) according to a third embodiment, respectively. The fluid injected from the two-stage combustion nozzle 20 includes premixed gas containing fuel and combustion air, and seal air (which will be described in detail below) which is a portion of the compressed air (combustion air) supplied from the compressor 2. The premixed gas and the seal air may be mixed in the combustion chamber 47, may be mixed inside the two-stage combustion nozzle 20, or may be mixed in both the combustion chamber 47 and the two-stage combustion nozzle 20.

The two-stage combustion nozzles 21 to 23 (20) include main body portions 11 to 13 that are provided in the combustion cylinders 40 and nozzle flow path forming portions 31 to 33 that are provided in the main body portions 11 to 13, respectively. The nozzle flow path forming portions 31 to 33 form nozzle flow paths 121 to 123 having nozzle injection ports 201 to 203, respectively. The premixed gas and the seal air flow through the nozzle flow paths 121 to 123, and the nozzle injection ports 201 to 203 inject the premixed gas and the seal air. Hereinafter, a central axis of the two-stage combustion nozzle 20 may be referred to as a “nozzle central axis C”, a circumferential direction of the nozzle central axis C may be referred to as a “nozzle circumferential direction”, and a radial direction of the nozzle central axis C may be referred to as a “nozzle radial direction”. The nozzle central axis C is also a center line of each of the main body portions 11 and 13. In addition, the radial direction of the combustion cylinder 40 may be referred to as a “combustion cylinder radial direction”. The nozzle central axis C extends in the combustion cylinder radial direction.

The nozzle flow path forming portions 31 to 33 include nozzle flow path walls 71 to 73 that are continuous with an inner peripheral surface 48 of the combustion cylinder 40, respectively. The nozzle flow path walls 71 to 73 include portions that extend along the combustion cylinder radial direction, and the portion is continuous with the inner peripheral surface 48. Nozzle flow path wall one end portions 711 to 713 which are one end portions of the nozzle flow path walls 71 to 73 in the combustion cylinder radial direction form the nozzle injection ports 201 to 203, respectively.

The nozzle injection ports 201 to 203 are formed in the inner peripheral surface 48 of the combustion cylinder 40. In this paper, the term “nozzle injection ports 201 to 203 formed in the inner peripheral surface 48” is a concept including the nozzle injection ports 201 to 203 disposed at the same positions in the radial direction as the inner peripheral surface 48 in the combustion cylinder radial direction.

In addition, the term “nozzle injection ports 201 to 203 formed in the inner peripheral surface 48″ is a concept including the nozzle injection ports 201 to 203 disposed outside the inner peripheral surface 48 in the combustion cylinder radial direction. In this case, a distance from the nozzle injection ports 201 to 203 to the inner peripheral surface 48 in the combustion cylinder radial direction is equal to or less than 20% of the diameter of the nozzle injection ports 201 to 203 formed in a circular shape. Further, the term ”nozzle injection ports 201 to 203 formed in the inner peripheral surface 48″ is a concept including the nozzle injection ports 201 to 203 disposed inside the inner peripheral surface 48 in the combustion cylinder radial direction. In this case, the distance from the nozzle injection ports 201 to 203 to the inner peripheral surface 48 in the combustion cylinder radial direction is equal to or less than 5% of the diameter of the nozzle injection ports 201 to 203 formed in the circular shape.

The two-stage combustion nozzles 21 to 23 further include seal air flow path forming portions 51 to 53 that are provided in the main body portions 11 to 13, respectively. The seal air flow path forming portions 51 to 53 form seal air flow paths 141 to 143 having seal air injection ports 41 to 43, respectively. The seal air flows through the seal air flow paths 141 to 143.

The seal air flow paths 141 and 142 shown in FIGS. 3A and 3B are flow paths included in the nozzle flow paths 121 and 122, respectively. A specific configuration is as follows. The seal air flow path forming portions 51 and 52 include inner flow path walls 81 and 82 that are disposed inside the nozzle flow path wall 71, respectively. In addition, the nozzle flow path walls 71 and 72 are also components of the seal air flow path forming portions 51 and 52, respectively, and the seal air flow paths 141 and 142 are formed between the nozzle flow path walls 71 and 72 and the inner flow path walls 81 and 82, respectively.

The inner flow path wall 81 shown in FIG. 3A extends along the combustion cylinder radial direction to surround the nozzle central axis C. A premixed gas flow path 91 through which the premixed gas flows is formed inside the inner flow path wall 81, and an inner flow path wall one end portion 811 which is one end portion of the inner flow path wall 81 forms a premixed gas injection port 813 for injecting the premixed gas. The premixed gas flow path 91 forms a portion of the nozzle flow path 121.

The inner flow path wall 82 shown in FIG. 3B extends along the combustion cylinder radial direction. A premixed gas flow path 92 through which the premixed gas flows is formed between the inner flow path wall 82 and the nozzle flow path wall 72. The premixed gas flow path 92 forms a portion of the nozzle flow path 122. An inner flow path wall one end portion 812 which is one end portion of the inner flow path wall 82 and the nozzle flow path wall one end portion 712 form a premixed gas injection port 823 for injecting the premixed gas.

The premixed gas injection ports 813 and 823 shown in FIGS. 3A and 3B form portions of the nozzle injection ports 201 and 202, respectively. The premixed gas and the seal air are injected from the two-stage combustion nozzle 20 and mixed in the combustion chamber 47 by the adoption of this configuration. However, the present disclosure is not limited thereto. For example, a configuration may be adopted in which the premixed gas and the seal air are mixed before passing through the nozzle injection port 201 in the two-stage combustion nozzle 21 (which will be described in detail below). The same applies to the two-stage combustion nozzle 22. In addition, the premixed gas injection ports 813 and 823 are examples of a fuel injection port for injecting fuel.

The premixed gas flow paths 91 and 92 have a plurality of air supply ports 95 that are disposed on a side opposite to the premixed gas injection ports 813 and 823 and a plurality of fuel supply ports 96 that are disposed between the premixed gas injection ports 813 and 823 and the plurality of air supply ports 95, respectively. The premixed gas is generated by mixing the combustion air supplied from the plurality of air supply ports 95 and the fuel supplied from the plurality of fuel supply ports 96. The premixed gas flow paths 91 and 92 are examples of a fuel channel through which the fuel flows.

The seal air flow path 143 shown in FIG. 3C is a flow path that is disposed on a side opposite to the nozzle central axis C with respect to the nozzle flow path wall 73 and is a flow path separate from the nozzle flow path 123. Then, the seal air injection port 43 is open in the nozzle flow path wall 73. The premixed gas and the seal air are mixed inside the two-stage combustion nozzle 20 before being injected from the two-stage combustion nozzle 20 by the adoption of this configuration.

In the present example, a plurality of seal air injection ports 43 are disposed at equal intervals in the nozzle circumferential direction. The seal air injection port 43 is configured to inject the seal air toward the nozzle injection port 203. It is preferable that an acute angle θ formed between a center line P of an outlet-side flow path 143A including the seal air injection port 43 and the nozzle central axis C in the seal air flow path 143 is less than 30 degrees.

In the nozzle flow path 123 shown in FIG. 3C, a plurality of air supply ports 95 that are the same as those in FIGS. 3A and 3B are provided on the side opposite to the nozzle injection port 203 with respect to the plurality of seal air injection ports 43, and a plurality of fuel supply ports 96 that are the same as those in FIGS. 3A and 3B are provided between the plurality of seal air injection ports 43 and the plurality of air supply ports 95. The premixed gas generated by mixing the combustion air and the fuel is mixed with at least a portion of the seal air supplied from the plurality of air supply ports 95 and is then injected from the nozzle injection port 203.

At least a portion of each of the seal air injection ports 41 to 43 shown in FIGS. 3A to 3C is disposed on the upstream side of the nozzle central axis C in the combustion gas flow direction. Specifically, the seal air injection ports 41 and 43 are disposed on the upstream and downstream sides of the nozzle central axis C in the combustion gas flow direction, and the seal air injection port 42 is disposed only on the upstream side of the nozzle central axis C in the combustion gas flow direction.

According to the inventors'findings, in a process in which the combustion gas as the main flow high-temperature gas generated inside the combustion chamber 47 flows toward the downstream side, a horseshoe vortex S of the combustion gas is formed on the inner peripheral surface 48. When the horseshoe vortex S flows into the nozzle injection ports 201 to 203, there is a concern that flashback causing ignition inside the two-stage combustion nozzle 20 will occur. In this regard, at least a portion of each of the seal air injection ports 41 to 43 is disposed on the upstream side of the nozzle central axis C in the combustion gas flow direction such that the seal air passes through a region on the upstream side of the nozzle central axis C in the combustion gas flow direction in the nozzle injection ports 201 to 203. The flow of the horseshoe vortex S into the nozzle injection ports 201 to 203 is suppressed by the flow of the seal air in the nozzle injection ports 201 to 203. That is, the seal air serves as a seal function of preventing the combustion gas as the main flow high-temperature gas from flowing into the nozzle injection ports 201 to 203. Therefore, the gas turbine combustor 4 that can suppress flashback is achieved.

In the embodiments shown in FIGS. 3A and 3B, the nozzle flow path walls 71 and 72 are also components of the seal air flow path forming portions 51 and 52, respectively, and the seal air flow paths 141 and 142 are formed between the nozzle flow path walls 71 and 72 and the inner flow path walls 81 and 82, respectively. According to the above-described configuration, the inner flow path walls 81 and 82 not only form the premixed gas flow paths 91 and 92, but also form the seal air flow paths 141 and 142, respectively. Therefore, the configuration of the gas turbine combustor 4 can be simplified as compared to a case where a dedicated flow path wall forming the seal air flow path 143 is disposed outside the nozzle flow path walls 71 and 72.

In addition, the seal air flow path 142 shown in FIG. 3B is disposed only on the upstream side of the nozzle central axis C in the combustion gas flow direction. The above-described configuration makes it possible to effectively suppress flashback while suppressing the total flow rate of air used as the seal air in the compressed air (combustion air) sent from the compressor 2.

In addition, in the embodiment shown in FIG. 3C, as described above, the seal air flow path forming portion 53 is disposed on the side opposite to the nozzle central axis C with respect to the nozzle flow path wall 73, and the seal air injection port 43 is open in the nozzle flow path wall 73. The above-described configuration makes it possible to freely adjust the position where the seal air injection port 43 is disposed in the axial direction of the nozzle central axis C at a design stage of the two-stage combustion nozzle 20. Therefore, it is possible to achieve both that the seal air prevents the inflow of the horseshoe vortex S and that the seal air is well mixed with the premixed gas inside the combustion chamber 47.

4. Details of Configurations that Can Be Additionally Adopted in Two-stage Combustion Nozzle 21 (20)

A configuration that can be additionally applied to the two-stage combustion nozzle 21 will be described with reference to FIGS. 4A to 9. Hereinafter, configurations according to first to seventh examples will be described in order. In addition, only one of the configurations according to the first to seventh examples may be applied to the two-stage combustion nozzle 21, or any combination of two or more of the configurations may be applied to the two-stage combustion nozzle 21.

4-1. Configuration According to First Example

The configuration according to the first example will be described with reference to FIGS. 4A to 4C. FIGS. 4A to 4C are schematic views showing two-stage combustion nozzles 21A, 21B, and 21C (21) that are two-stage combustion nozzles 21 to which the configuration according to the first example is applied and show the two-stage combustion nozzles 21 when viewed in the axial direction of the nozzle central axis C. FIGS. 4A to 4C show different types of configurations according to the first example.

Nozzle flow path walls 71A, 71B, and 71C (71) of the two-stage combustion nozzles 21A, 21B, and 21C (21) include upstream-side flow path walls 76A, 76B, and 76C (76) that are disposed on the upstream side of the nozzle central axis C in the combustion gas flow direction and downstream-side flow path walls 79A, 79B, and 79C (79) that are disposed on the downstream side of the nozzle central axis C in the combustion gas flow direction, respectively. Then, seal air flow paths 141A, 141B, and 141C (141) include upstream-side seal air flow paths 146A, 146B, and 146C (146) each of which is formed by the upstream-side flow path wall 76 and the inner flow path wall 81 and downstream-side seal air flow paths 149A, 149B, and 149C (149) each of which is formed by the downstream-side flow path wall 79 and the inner flow path wall 81, respectively.

The inner flow path wall 81 shown in FIGS. 4A and 4B is surrounded by the upstream-side flow path wall 76A or 76B and the downstream-side flow path wall 79A or 79B in the nozzle circumferential direction. The nozzle flow path wall 71A or 71B has a circular shape when viewed in the axial direction of the nozzle central axis C. Meanwhile, in the example shown in FIG. 4C, the upstream-side flow path wall 76C has the same semicircular shape as the upstream-side flow path walls 76A and 76B, and the downstream-side flow path wall 79C has an arc shape having a shorter circumferential length than the upstream-side flow path wall 76C. The nozzle flow path wall 71C has a C-shape when viewed in the axial direction of the nozzle central axis C and is disposed to surround only a portion of the inner flow path wall 81 in the nozzle circumferential direction.

According to the configuration of the first example shown in FIGS. 4A to 4C, the seal air flow paths 141A to 141C (141) include the upstream-side seal air flow paths 146A, 146B, and 146C (146) and the downstream-side seal air flow paths 149A, 149B, and 149C (149), respectively. Therefore, the seal air injected from the seal air injection port 41 not only passes through a region on the upstream side of the nozzle central axis C in each of the nozzle injection ports 201A to 201C (201), but also passes through a region on the downstream side of the nozzle central axis C. As a result, the premixed gas containing the fuel injected from the nozzle injection port 201 can be evenly mixed with the seal air.

In addition, as shown in FIG. 4B, the flow path area of the upstream-side seal air flow path 146B is larger than the flow path area of the downstream-side seal air flow path 149B when viewed in the axial direction of the nozzle central axis C. That is, the flow path area of the upstream-side seal air flow path 146B is larger than the flow path area of the downstream-side seal air flow path 149B in a cross section orthogonal to the nozzle central axis C. This magnitude relationship between the flow path areas is achieved by eccentrically positioning the inner flow path wall 81 formed in a cylindrical shape relative to the nozzle flow path wall 71 such that the axial center of the inner flow path wall 81 is located on the downstream side of the nozzle central axis C in the combustion gas flow direction. The horseshoe vortex S occurring on the inner peripheral surface 48 of the combustion cylinder 40 tends to flow into the nozzle injection port 201 on the upstream side of the nozzle central axis C in the combustion gas flow direction (this is clear from the flow direction of the horseshoe vortex S represented by arrows in FIG. 3A). In this regard, according to the above-described configuration, since the flow rate of the seal air flowing through the upstream-side seal air flow path 146B increases, the flow of the seal air can more effectively suppress the inflow of the horseshoe vortex S. Therefore, the gas turbine combustor 4 can more reliably suppress flashback.

As shown in FIG. 4C, the length of the upstream-side flow path wall 76C in the nozzle circumferential direction is larger than the length of the downstream-side flow path wall 79C in the nozzle circumferential direction (the length of the downstream-side flow path wall 79C in the nozzle circumferential direction is the sum of dimensions L1 and L2). According to the above-described configuration, since the flow rate of the seal air flowing through the upstream-side seal air flow path 146C increases, the flow of the seal air can more effectively suppress the inflow of the horseshoe vortex S. Therefore, the gas turbine combustor 4 can more reliably suppress flashback. Further, in the embodiment in which the seal air is not required on the downstream side of the nozzle central axis C in the combustion gas flow direction, the seal air can be concentrated on the upstream side of the nozzle central axis C in the combustion gas flow direction. Therefore, it is possible to more effectively suppress flashback.

4-2. Configuration According to Second Example

The configuration according to the second example will be described with reference to FIGS. 5A to 5C. FIGS. 5A and 5B are schematic views showing a two-stage combustion nozzle 21D that is a two-stage combustion nozzle 21 to which the configuration according to the second example is applied. FIG. 5C is a cross-sectional view showing a partition wall 55 taken along line A-A in FIG. 5A.

The two-stage combustion nozzle 21D (21) shown in FIG. 5A further includes at least one partition wall 55 in addition to the configuration of the two-stage combustion nozzle 21A (21) shown in FIG. 3A. The partition wall 55 is connected to the nozzle flow path wall 71A and the inner flow path wall 81 in the seal air flow path 141. In addition, the partition wall 55 extends along the nozzle central axis C.

As shown in FIG. 5B, a plurality of partition walls 55 may be disposed at equal intervals along the nozzle circumferential direction. Each partition wall 55 defines two spaces adjacent to each other in the nozzle circumferential direction, and the flow of the seal air between the two spaces is regulated by the partition wall 55. In addition, the number of partition walls 55 may be one.

The seal air in the seal air injection port 41 may be swept to the downstream side in the combustion gas flow direction along the nozzle circumferential direction due to the influence of the flow of the horseshoe vortex S. In this regard, since the two-stage combustion nozzle 21D includes at least one partition wall 55, the partition wall 55 can regulate the flow of the seal air in the nozzle circumferential direction. Therefore, a bias in the pressure distribution of the seal air in the seal air injection port 41 in the nozzle circumferential direction is suppressed, which makes it possible to smooth the flow of the seal air in the seal air injection port 41.

As shown in FIG. 5A, the partition wall 55 includes a tip portion 55A and a rear end portion 55B. The tip portion 55A is a downstream-side end portion of the partition wall 55 in the seal air flow direction (that is, the flow direction of the seal air in the seal air flow path 141). In addition, the rear end portion 55B is an end portion of the partition wall 55 opposite to the tip portion 55A. The tip portion 55A is disposed on the upstream side of the seal air injection port 41 in the seal air flow direction. It is preferable that the shortest distance from the tip portion 55A to the seal air injection port 41 (a dimension M shown as a distance in the combustion cylinder radial direction) is equal to or less than 50% of the inner diameter of the nozzle injection port 201 formed in the circular shape. In addition, it is preferable that the length of the partition wall 55 in the axial direction is equal to or greater than 50% of the diameter of the nozzle injection port 201.

According to the above-described configuration, since the partition wall 55 is provided, it is possible to suppress the uneven distribution of the injected seal air in the circumferential direction. Therefore, even in a case where the pressure of the combustion chamber 47 on the upstream side in the gas flow direction in which the seal air is required is high, it is possible to sufficiently supply the seal air.

As shown in FIG. 5C, at least one of the tip portion 55A or the rear end portion 55B may have a streamlined shape. In the example shown in FIG. 5C, both the tip portion 55A and the rear end portion 55B have a streamlined shape. Specifically, the length of the tip portion 55A in the nozzle circumferential direction is reduced toward the downstream side in the seal air flow direction, and the length of the rear end portion 55B in the nozzle circumferential direction is reduced toward the upstream side in the seal air flow direction. In addition, both the tip portion 55A and the rear end portion 55B are connected to the nozzle flow path wall 71A and the inner flow path wall 81.

According to the above-described configuration, it is possible to suppress the stagnation of the seal air flowing toward the seal air injection port 41.

4-3. Configuration According to Third Example

The configuration according to the third example will be described with reference to FIGS. 6A and 6B. FIGS. 6A and 6B are schematic views showing two-stage combustion nozzles 21E and 21F (21) to which the configuration according to the third example is applied, respectively. FIGS. 6A and 6B show different types of configurations according to the third example.

Each of the two-stage combustion nozzles 21E and 21F (21) shown in FIGS. 6A and 6B, respectively, include a turbulator 57 in addition to the configuration of the two-stage combustion nozzle 21A (21) shown in FIG. 3A. Specifically, the nozzle flow path wall 71A (71) has an inner surface 77 that faces the inner flow path wall 81, the inner flow path wall 81 has an outer surface 88 that faces the nozzle flow path wall 71A, and the turbulator 57 is provided on at least one of the inner surface 77 or the outer surface 88. The turbulators 57 shown in FIGS. 6A and 6B are provided on both the inner surface 77 and the outer surface 88, but may be provided on only one of the inner surface 77 or the outer surface 88.

The turbulators 57 may be provided on the inner surface 77 over the entire length of the inner surface 77 in the nozzle circumferential direction or may be provided only on a portion of the inner surface 77 in the nozzle circumferential direction. A plurality of turbulators 57 provided only on a portion of the inner surface 77 may be disposed on the inner surface 77 at equal intervals along the nozzle circumferential direction.

Similarly, the turbulators 57 may be provided on the outer surface 88 over the entire length of the outer surface 88 in the nozzle circumferential direction or may be provided only on a portion of the outer surface 88 in the nozzle circumferential direction. The turbulators 57 provided only on a portion of the outer surface 88 may be disposed on the outer surface 88 at equal intervals along the nozzle circumferential direction.

According to the above-described configuration, since the turbulators 57 are provided in the seal air flow path 141, the secondary flow of the seal air occurs in the seal air flow path 141. Since the flow of the seal air injected from the seal air injection port 41 is disturbed, the seal air that has completed the seal function of preventing the inflow of the horseshoe vortex S and that flows toward the center of the combustion chamber 47 is likely to be mixed with the premixed gas containing the fuel. Therefore, the high-temperature combustion gas and the seal air can be quickly mixed inside the combustion chamber 47 to reduce the temperature of the surrounding combustion gas. As a result, it is possible to suppress the generation of NOx.

As shown in FIG. 6A, it is preferable that the turbulators 57 according to the embodiment of the present disclosure are disposed at least on the upstream side of the nozzle central axis C in the combustion gas flow direction. According to this configuration, it is possible to promote the mixing of the seal air, which has completed the seal function of preventing the inflow of the horseshoe vortex S, with the premixed gas containing the fuel. The mixed air is mixed with the burnt gas on the upstream side in the combustion gas flow direction inside the combustion chamber 47 to reduce the temperature of the burnt gas. Therefore, it is possible to suppress the generation of NOX.

As shown in FIG. 6B, the turbulators 57 according to another embodiment of the present disclosure may be disposed only on the downstream side of the nozzle central axis C in the combustion gas flow direction. On the downstream side of the nozzle injection port 201 in the combustion gas flow direction, there is a low tendency for the horseshoe vortex S to flow into the nozzle injection port 201. That is, there is a case where the seal air flowing to the downstream side of the nozzle central axis C does not need to prevent the inflow of the horseshoe vortex S. In this regard, according to the above-described configuration, it is possible to actively disturb the flow of the seal air and to promote the mixing of the seal air with the premixed gas containing the fuel.

4-4. Configuration According to Fourth Example

The configuration according to the fourth example will be described with reference to FIGS. 7A and 7B. FIGS. 7A and 7B are schematic views showing a two-stage combustion nozzle 21G (21) to which the configuration according to the fourth example is applied. In addition, for the sake of making the drawings easier to see, an inner flow path wall 81G (see FIG. 7B) is not shown in FIG. 7A, and a nozzle flow path wall one end portion 711G (see FIG. 7A) is partially not shown in FIG. 7B.

The nozzle flow path wall 71G (71) of the two-stage combustion nozzle 21G (21) shown in FIG. 7A has the nozzle flow path wall one end portion 711G (711) forming a nozzle injection port 201G (201). Then, the nozzle flow path wall one end portion 711G extends in a zigzag shape along the nozzle circumferential direction.

The inner flow path wall 81G (81) of the two-stage combustion nozzle 21G (21) shown in FIG. 7B has an inner flow path wall one end portion 811G (811) forming a premixed gas injection port 813G (813). Then, the inner flow path wall one end portion 811G extends in a zigzag shape along the nozzle circumferential direction.

In addition, the present disclosure is not limited to the case where both the nozzle flow path wall one end portion 711G (711) and the inner flow path wall one end portion 811G (811) extend in a zigzag shape. Only one of the nozzle flow path wall one end portion 711G (711) or the inner flow path wall one end portion 811G (811) may extend in a zigzag shape. In this case, the other may extend linearly along the nozzle circumferential direction.

According to the above-described configuration, in the seal air injection port 41G (41) formed by the inner flow path wall one end portion 811G and the nozzle flow path wall one end portion 711G, the secondary flow of the seal air occurs. Since the flow of the seal air injected from the seal air injection port 41G (41) is disturbed, the seal air that has completed the seal function of preventing the inflow of the horseshoe vortex S and that flows toward the center of the combustion chamber 47 is likely to be mixed with the fuel. Therefore, the surrounding high-temperature combustion gas and the seal air can be quickly mixed inside the combustion chamber 47 to reduce the temperature of the surrounding combustion gas. As a result, it is possible to suppress the generation of NOx.

4-5. Configuration According to Fifth Example

The configuration according to the fifth example will be described with reference to FIGS. 8A to 8D. FIG. 8A is a schematic view showing a two-stage combustion nozzle 21H (21) that is a two-stage combustion nozzle 21 to which the configuration according to the fifth example is applied. FIGS. 8B and 8C are schematic views showing two-stage combustion nozzles 21I and 21J (21H) which are more specific versions of the two-stage combustion nozzle 21H shown in FIG. 8A.

As shown in FIG. 8A, an inner flow path wall 81H (81) of the two-stage combustion nozzle 21H (21) has an inner flow path wall one end portion 811H (811) forming a premixed gas injection port 813H (813). A nozzle flow path wall 71H (71) of the two-stage combustion nozzle 21H shown in FIG. 8A extends parallel to the nozzle central axis C. However, a portion of the nozzle flow path wall 71H may not be parallel to the nozzle central axis C, which will be described below (see FIG. 8C). The inner flow path wall one end portion 811H is disposed on the upstream side of the nozzle injection port 201H (201) in the seal air flow direction. According to the above-described configuration, the inner flow path wall one end portion 811H can be kept away from the combustion gas as the main flow high-temperature gas flowing through the combustion chamber 47. Therefore, it is possible to suppress the burnout of the inner flow path wall one end portion 811H.

Further, in a case where this configuration is adopted, the seal air injection port 41H (41) formed by the inner flow path wall one end portion 811H and the nozzle flow path wall 71H is disposed on the upstream side of the nozzle injection port 201H in the seal air flow direction. Therefore, at least a portion of the seal air is mixed with the premixed gas and then injected from the nozzle injection port 201H.

The two-stage combustion nozzle 21I (21H) shown in FIG. 8B has an inner flow path wall 81I (81H), and an inner flow path wall one end portion 811I (811H) of the inner flow path wall 81H has an inner tapered surface 815. The inner tapered surface 815 faces inward in the nozzle radial direction (that is, toward the nozzle central axis C) and is inclined to be further away from the nozzle central axis C as the inner tapered surface 815 approaches the combustion chamber 47.

The two-stage combustion nozzle 21J (21H) shown in FIG. 8C has an inner flow path wall 81J (81H), and an inner flow path wall one end portion 811J (811H) of the inner flow path wall 81J has an outer tapered surface 818. The outer tapered surface 818 faces outward in the nozzle radial direction (that is, the side opposite to the nozzle central axis C) and is inclined to be closer to the nozzle central axis C as the outer tapered surface 818 approaches the combustion chamber 47.

According to the configuration in which the inner flow path wall one end portion 811H has the outer tapered surface 818 or the inner tapered surface 815, since the shape of the inner flow path wall one end portion 811H is a tapered shape, it is possible to suppress the stagnation of the premixed gas in the vicinity of the inner flow path wall one end portion 811H (for example, a region R in the two-stage combustion nozzle 20H on the downstream side of the inner flow path wall one end portion 811H in the seal air flow direction). Therefore, the premixed gas can be vigorously injected from the nozzle injection port 201H. In addition, the inner flow path wall one end portion 811H according to the present disclosure is not limited to the configuration having only one of the inner tapered surface 815 or the outer tapered surface 818 and may have both the inner tapered surface 815 and the outer tapered surface 818. In this case, the above-described advantage of suppressing the stagnation of the premixed gas is also obtained.

As shown in FIG. 8C, a nozzle flow path wall 71J (71H) of the two-stage combustion nozzle 21J (21H) may have an opposite inclined surface 75. The opposite inclined surface 75 faces the outer surface 88 and is inclined to be closer to the nozzle central axis C as the opposite inclined surface 75 approaches the nozzle injection port 201J (201H). In FIG. 8C, as an example, the opposite inclined surface 75 is parallel to the outer surface 88.

According to the above-described configuration, an increase in the flow path area of a seal air flow path 141J (141H) of the two-stage combustion nozzle 21J as the seal air flow path 141J (141H) approaches the seal air injection port 41J (41H) is suppressed. Therefore, it is possible to avoid a decrease in the momentum of the seal air in the seal air injection port 41J. Therefore, it is possible to vigorously inject the premixed gas from the nozzle injection port 201J (201H) and to suppress the flow of the horseshoe vortex S into the nozzle injection port 201J.

<4-6. Configuration According to Sixth Example>The configuration according to the sixth example will be described with reference to FIG. 9. FIG. 9 is a schematic view showing a two-stage combustion nozzle 21K (21) to which the configuration according to the sixth example is applied. A nozzle injection port 201K (201) and a premixed gas injection port 813K (813) of the two-stage combustion nozzle 21K (21) have an elliptical shape that is long in the combustion gas flow direction when viewed in the axial direction of the nozzle central axis C.

In the embodiment in which the nozzle injection port 201K (201) has an elliptical shape, when the “nozzle injection port 201 formed in the inner peripheral surface 48 of the combustion cylinder 40” is disposed outside the inner peripheral surface 48 in the combustion cylinder radial direction, a distance between the inner peripheral surface 48 and the nozzle injection port 201 in the combustion cylinder radial direction is equal to or less than 20% of the hydraulic diameter of the nozzle injection port 201K.

In addition, in the embodiment in which the nozzle injection port 201K (201) has an elliptical shape, when the “nozzle injection port 201 formed in the inner peripheral surface 48 of the combustion cylinder 40” is disposed inside the inner peripheral surface 48 in the combustion cylinder radial direction, the distance between the inner peripheral surface 48 and the nozzle injection port 201 in the combustion cylinder radial direction is equal to or less than 5% of the hydraulic diameter of the nozzle injection port 201K.

In addition, the two-stage combustion nozzle 21K may include the partition wall 55 (see FIG. 5A). In this case, it is preferable that the shortest distance (the distance in the combustion cylinder radial direction) from the tip portion 55A of the partition wall 55 to the seal air injection port 41K (41) is equal to or less than 25% of the length of the nozzle injection port 201K in the combustion gas flow direction.

4-7. Supplementary Description

The present disclosure is not limited to the application of the configurations according to the first to seventh examples to the two-stage combustion nozzle 21. At least one of these configurations may be applied to the two-stage combustion nozzles 22 and 23. A detailed description thereof will be omitted in order to avoid redundant description.

5. Summary

For example, the content described in some embodiments described above is understood as follows.

1) A gas turbine combustor (4) according to at least one embodiment of the present disclosure includes:

• • a combustion cylinder (40) that defines a combustion chamber (47);
  • a combustor (8) that supplies a fuel to the combustion chamber; and
  • a two-stage combustion nozzle (20) that is disposed on a downstream side of the combustor in a flow direction of a combustion gas in the combustion chamber,
  • in which the two-stage combustion nozzle includes
  • a nozzle flow path forming portion (31 to 33) that forms a nozzle flow path (121 to 123) having a nozzle injection port (201 to 203) formed in an inner peripheral surface of the combustion cylinder, and
  • a seal air flow path forming portion (51 to 53) that forms a seal air flow path (141 to 143) having a seal air injection port (41 to 43) at least a portion of which is disposed on an upstream side of a nozzle central axis (C), which is a center line of the two-stage combustion nozzle, in the flow direction of the combustion gas.

According to the configuration of 1), the seal air injected from the seal air injection port passes through a region on the upstream side of the nozzle central axis in the nozzle injection port. The flow of the horseshoe vortex(S) of the high-temperature combustion gas, which occurs in the inner peripheral surface of the combustion cylinder, into the nozzle injection port is suppressed by the flow of the seal air in the nozzle injection port. Therefore, a gas turbine combustor that can suppress flashback is achieved.

2) In some embodiments, in the gas turbine combustor according to 1),

• • the nozzle flow path forming portion has a nozzle flow path wall (71 to 73) that is continuous with the inner peripheral surface of the combustion cylinder, and
  • the seal air flow path forming portion further includes
  • the nozzle flow path wall, and
  • an inner flow path wall (81, 82) that is disposed inside the nozzle flow path wall and forms a fuel channel (premixed gas flow path 91, 92) through which the fuel flows.

According to the configuration of 2), the inner flow path wall not only forms the fuel channel but also forms the seal air flow path. Therefore, it is possible to simplify the configuration of the gas turbine combustor as compared to a case where a dedicated flow path wall for forming the seal air flow path is disposed outside the nozzle flow path wall.

3) In some embodiments, in the gas turbine combustor according to 2),

• • the nozzle flow path wall includes
  • an upstream-side flow path wall (76) that is disposed on the upstream side of the nozzle central axis in the flow direction of the combustion gas, and
  • a downstream-side flow path wall (79) that is disposed on a downstream side of the nozzle central axis in the flow direction of the combustion gas, and
  • the seal air flow path includes
  • an upstream-side seal air flow path (146) that is formed by the upstream-side flow path wall and the inner flow path wall, and
  • a downstream-side seal air flow path (149) that is formed by the downstream-side flow path wall and the inner flow path wall.

According to the configuration of 3), the seal air injected from the seal air injection port not only passes through the region on the upstream side of the nozzle central axis in the nozzle injection port, but also passes through the region on the downstream side of the nozzle central axis. Therefore, it is possible to evenly mix the fuel injected from the nozzle injection port with the seal air.

• • 4) In some embodiments, in the gas turbine combustor according to 3),
  • in a cross section of the seal air flow path orthogonal to the nozzle central axis, a flow path area of the upstream-side seal air flow path is larger than a flow path area of the downstream-side seal air flow path.

The horseshoe vortex occurring on the inner peripheral surface of the combustion cylinder tends to flow into the nozzle injection port on the upstream side of the nozzle central axis in the flow direction of the combustion gas. In this regard, according to the configuration of 4), since the flow rate of the seal air flowing through the upstream-side seal air flow path increases, the inflow of the horseshoe vortex can be more effectively suppressed by the flow of the seal air. Therefore, the gas turbine combustor can more reliably suppress flashback.

5) In some embodiments, in the gas turbine combustor according to 3) or 4),

• • a length of the upstream-side seal air flow path in a nozzle circumferential direction, which is a circumferential direction of the nozzle central axis, is larger than a length of the downstream-side seal air flow path in the nozzle circumferential direction.

According to the configuration of 5), since the flow rate of the seal air flowing through the upstream-side seal air flow path increases, the gas turbine combustor can more reliably suppress flashback for the same reason as in 4). In addition, since the seal air can be concentrated on the upstream side of the nozzle central axis C in the combustion gas flow direction, it is possible to more effectively suppress flashback.

6) In some embodiments, in the gas turbine combustor according to 2),

• • the seal air flow path is formed only on the upstream side of the nozzle central axis in the flow direction of the combustion gas.

According to the configuration of 6), since the nozzle air flow path is formed only on the upstream side of the nozzle central axis, the gas turbine combustor can effectively suppress flashback while suppressing the total flow rate of the film air.

• • 7) In some embodiments, in the gas turbine combustor according to any one of 2) to 6),
  • the two-stage combustion nozzle further includes a partition wall (55) that is connected to the nozzle flow path wall and the inner flow path wall in the seal air flow path.

The seal air in the seal air injection port may be swept to the downstream side in the flow direction of the combustion gas along the nozzle circumferential direction due to the influence of the flow of the horseshoe vortex. In this regard, according to the configuration of 7), even in this case, the partition wall can regulate the flow of the seal air in the nozzle circumferential direction. Therefore, a bias in the pressure distribution of the seal air in the seal air injection port in the nozzle circumferential direction is suppressed, which makes it possible to smooth the flow of the seal air in the seal air injection port.

8) In some embodiments, in the gas turbine combustor according to 7),

• • the partition wall has a tip portion (55A) which is a downstream-side end portion in a flow direction of seal air in the seal air flow path, and
  • the tip portion of the partition wall is disposed on an upstream side of the seal air injection port in the flow direction of the seal air.

According to the configuration of 8), since the partition wall is provided, it is possible to suppress the uneven distribution of the injected seal air in the circumferential direction. Therefore, even in a case where the pressure of the combustion chamber 47 on the upstream side in the gas flow direction in which the seal air is required is high, it is possible to sufficiently supply the seal air.

9) In some embodiments, in the gas turbine combustor according to 7) or 8),

• • the partition wall has
  • a tip portion (55A) which is a downstream-side end portion in a flow direction of seal air in the seal air flow path, and
  • a rear end portion (55B) which is an end portion opposite to the tip portion, and
  • at least one of the tip portion or the rear end portion has a streamlined shape.

According to the configuration of 9), since the stagnation of the seal air flowing toward the seal air injection port is suppressed, the seal air is vigorously injected from the seal air injection port. Therefore, it is possible to further suppress the flow of the horseshoe vortex into the nozzle injection port.

10) In some embodiments, in the gas turbine combustor according to any one of 2) to 9),

• • the nozzle flow path wall has an inner surface (77) that faces the inner flow path wall,
  • the inner flow path wall has an outer surface (88) that faces the nozzle flow path wall, and
  • the two-stage combustion nozzle further includes a turbulator (57) that is provided on at least one of the inner surface or the outer surface.

According to the configuration of 10), since the turbulator is provided in the seal air flow path, the secondary flow of the seal air occurs in the seal air flow path. Since the flow of the seal air injected from the seal air injection port is disturbed, the seal air that has completed the seal function of preventing the inflow of the horseshoe vortex and that flows toward the center of the combustion chamber is likely to be mixed with the fuel. Therefore, the high-temperature combustion gas and the seal air can be quickly mixed inside the combustion chamber to reduce the temperature of the surrounding combustion gas. As a result, it is possible to suppress the generation of NOX.

11) In some embodiments, in the gas turbine combustor according to 10),

• • the turbulator is disposed at least on the upstream side of the nozzle central axis in the flow direction of the combustion gas.

According to the configuration of 11), it is possible to promote the mixing of the seal air, which has completed the seal function of preventing the inflow of the horseshoe vortex, with the fuel. The mixed air can be mixed with the burnt gas on the upstream side in the combustion gas flow direction inside the combustion chamber to reduce the temperature of the burnt gas. Therefore, it is possible to suppress the generation of NOx.

12) In some embodiments, in the gas turbine combustor according to 10),

• • the turbulator is disposed only on the downstream side of the nozzle central axis in the flow direction of the combustion gas.

On the downstream side of the nozzle injection port in the flow direction of the combustion gas, there is a low tendency for the horseshoe vortex to flow into the nozzle injection port. That is, there is a case where the seal air flowing on the downstream side of the nozzle central axis does not need to prevent the inflow of the horseshoe vortex. In this regard, according to the configuration of 12), it is possible to actively disturb the flow of the seal air and to promote the mixing of the seal air with the fuel.

13) In some embodiments, in the gas turbine combustor according to any one of 2) to 11),

• • the inner flow path wall has an inner flow path wall one end portion (811, 812) that forms a fuel injection port (813, 823) for injecting the fuel,
  • the nozzle flow path wall has a nozzle flow path wall one end portion (711 to 713) that forms the nozzle injection port, and
  • at least one of the inner flow path wall one end portion or the nozzle flow path wall one end portion extends in a zigzag shape along a nozzle circumferential direction which is a circumferential direction of the nozzle central axis.

According to the configuration of 13), in the seal air injection port formed by the inner flow path wall one end portion and the nozzle flow path wall one end portion, the secondary flow of the seal air occurs. Since the flow of the seal air injected from the seal air injection port is disturbed, the seal air that has completed the seal function of preventing the inflow of the horseshoe vortex and that flows toward the center of the combustion chamber is likely to be mixed with the fuel. Therefore, it is possible to suppress a combustion failure in the combustion chamber.

14) In some embodiments, in the gas turbine combustor according to any one of 2) to 13),

• • the inner flow path wall has an inner flow path wall one end portion (811, 812) that forms a fuel injection port (813, 823), and
  • the inner flow path wall one end portion is disposed on an upstream side of the nozzle injection port in a flow direction of seal air in the seal air flow path.

According to the configuration of 14), since the inner flow path wall one end portion can be kept away from the combustion gas flowing through the combustion chamber, it is possible to suppress damage to the inner flow path wall one end portion.

15) In some embodiments, in the gas turbine combustor described in 14),

• • the fuel injection port is a premixed gas injection port that is configured to inject a premixed gas containing the fuel and combustion air, and
  • the inner flow path wall one end portion has at least one of an outer tapered surface (818) that faces outward in a nozzle radial direction which is a radial direction of the nozzle central axis and that is inclined to be closer to the nozzle central axis as the outer tapered surface approaches the combustion chamber or an inner tapered surface (815) that faces inward in the nozzle radial direction and that is inclined to be further away from the nozzle central axis as the inner tapered surface approaches the combustion chamber.

According to the configuration of 15), since the inner flow path wall one end portion is tapered, it is possible to suppress the stagnation of the premixed gas in the vicinity of the inner flow path wall one end portion. Therefore, the premixed gas can be vigorously injected from the nozzle injection port.

16) In some embodiments, in the gas turbine combustor according to 15),

• • the inner flow path wall one end portion has the outer tapered surface, and
  • the nozzle flow path wall has an opposite inclined surface (75) that faces the outer tapered surface and that is inclined to be closer to the nozzle central axis as the opposite inclined surface approaches the nozzle injection port.

According to the configuration of 16), an increase in the flow path area of the seal air flow path as the seal air flow path approaches the seal air injection port is suppressed. Therefore, it is possible to avoid a decrease in the momentum of the seal air in the seal air injection port. Therefore, the gas turbine combustor can vigorously inject the premixed gas from the nozzle injection port and can suppress the flow of the horseshoe vortex into the nozzle injection port.

17) In some embodiments, in the gas turbine combustor according to 1),

• • the nozzle flow path forming portion has a nozzle flow path wall (711 to 713) that is continuous with the inner peripheral surface of the combustion cylinder,
  • the seal air flow path forming portion is disposed on a side opposite to the nozzle central axis with respect to the nozzle flow path wall, and
  • the seal air injection port is open in the nozzle flow path wall and is configured to inject seal air toward the nozzle injection port.

According to the configuration of 17), it is possible to freely design the position where the seal air injection port is disposed. Therefore, it is possible to achieve both that the seal air prevents the inflow of the horseshoe vortex and that the seal air is well mixed with the fuel inside the combustion chamber.

REFERENCE SIGNS LIST

• • 4: Gas turbine combustor
  • 6: Turbine
  • 8: Combustor
  • 20: Stage combustion nozzle
  • 31 to 33: Nozzle flow path forming portion
  • 40: Combustion cylinder
  • 41 to 43: Seal air injection port
  • 47: Combustion chamber
  • 48: Inner peripheral surface
  • 55: Partition wall
  • 55A: Tip portion
  • 55B: Rear end portion
  • 57: turbulator
  • 71 to 73: Nozzle flow path wall
  • 75: Opposite inclined surface
  • 76: Upstream-side flow path wall
  • 77: Inner surface
  • 79: Downstream-side flow path wall
  • 81, 82: Inner flow path wall
  • 88: Outer surface
  • 100: Gas turbine
  • 121 to 123: Nozzle flow path
  • 141 to 143: Seal air flow path
  • 146: Upstream-side seal air flow path
  • 149: Downstream-side seal air flow path
  • 201 to 203: Nozzle injection port
  • 711 to 713: Nozzle flow path wall one end portion
  • 811, 812: Inner flow path wall one end portion
  • 813: Premixed gas injection port
  • 815: Inner tapered surface
  • 818: Outer tapered surface
  • 823: Premixed gas injection port
  • C: Nozzle central axis
  • P: Center line

Claims

1.-17. (canceled)

18. A gas turbine combustor comprising:

a combustion cylinder that defines a combustion chamber;

a combustor that supplies a fuel to the combustion chamber; and

a two-stage combustion nozzle that is disposed on a downstream side of the combustor in a flow direction of a combustion gas in the combustion chamber,

wherein the two-stage combustion nozzle includes

a nozzle flow path forming portion that forms a nozzle flow path having a nozzle injection port formed in an inner peripheral surface of the combustion cylinder, and

a seal air flow path forming portion that forms a seal air flow path having a seal air injection port at least a portion of which is disposed on an upstream side of a nozzle central axis, which is a center line of the two-stage combustion nozzle, in the flow direction of the combustion gas.

the nozzle flow path forming portion has a nozzle flow path wall that is continuous with the inner peripheral surface of the combustion cylinder,

the seal air flow path forming portion further includes

the nozzle flow path wall, and

an inner flow path wall that is disposed inside the nozzle flow path wall and forms a fuel channel through which the fuel flows,

the two-stage combustion nozzle further includes a partition wall that is connected to the nozzle flow path wall and the inner flow path wall in the seal air flow path.

the partition wall has a tip portion which is a downstream-side end portion in a flow direction of seal air in the seal air flow path and a rear end portion which is an end portion opposite to the tip portion, and

at least one of the tip portion or the rear end portion has a streamlined shape.

19. The gas turbine combustor according to claim 18,

wherein the nozzle flow path wall includes

an upstream-side flow path wall that is disposed on the upstream side of the nozzle central axis in the flow direction of the combustion gas, and

a downstream-side flow path wall that is disposed on a downstream side of the nozzle central axis in the flow direction of the combustion gas, and

the seal air flow path includes

an upstream-side seal air flow path that is formed by the upstream-side flow path wall and the inner flow path wall, and

a downstream-side seal air flow path that is formed by the downstream-side flow path wall and the inner flow path wall.

20. The gas turbine combustor according to claim 19,

wherein, in a cross section of the seal air flow path orthogonal to the nozzle central axis, a flow path area of the upstream-side seal air flow path is larger than a flow path area of the downstream-side seal air flow path.

21. The gas turbine combustor according to claim 19,

wherein a length of the upstream-side seal air flow path in a nozzle circumferential direction, which is a circumferential direction of the nozzle central axis, is larger than a length of the downstream-side seal air flow path in the nozzle circumferential direction.

22. The gas turbine combustor according to claim 18,

wherein the seal air flow path is formed only on the upstream side of the nozzle central axis in the flow direction of the combustion gas.

23. The gas turbine combustor according to claim 18,

wherein the partition wall has a tip portion which is a downstream-side end portion in a flow direction of seal air in the seal air flow path, and

the tip portion of the partition wall is disposed on an upstream side of the seal air injection port in the flow direction of the seal air.

24. The gas turbine combustor according to claim 18,

wherein the nozzle flow path wall has an inner surface that faces the inner flow path wall,

the inner flow path wall has an outer surface that faces the nozzle flow path wall, and

the two-stage combustion nozzle further includes a turbulator that is provided on at least one of the inner surface or the outer surface.

25. The gas turbine combustor according to claim 24,

wherein the turbulator is disposed at least on the upstream side of the nozzle central axis in the flow direction of the combustion gas.

26. The gas turbine combustor according to claim 24,

wherein the turbulator is disposed only on a downstream side of the nozzle central axis in the flow direction of the combustion gas.

27. The gas turbine combustor according to claim 18,

wherein the inner flow path wall has an inner flow path wall one end portion that forms a fuel injection port for injecting the fuel,

the nozzle flow path wall has a nozzle flow path wall one end portion that forms the nozzle injection port, and

at least one of the inner flow path wall one end portion or the nozzle flow path wall one end portion extends in a zigzag shape along a nozzle circumferential direction which is a circumferential direction of the nozzle central axis.

28. The gas turbine combustor according to claim 18,

wherein the inner flow path wall has an inner flow path wall one end portion that forms a fuel injection port, and

the inner flow path wall one end portion is disposed on an upstream side of the nozzle injection port in a flow direction of seal air in the seal air flow path.

29. The gas turbine combustor according to claim 28,

wherein the fuel injection port is a premixed gas injection port that is configured to inject a premixed gas containing the fuel and combustion air, and

the inner flow path wall one end portion has at least one of an outer tapered surface that faces outward in a nozzle radial direction which is a radial direction of the nozzle central axis and that is inclined to be closer to the nozzle central axis as the outer tapered surface approaches the combustion chamber or an inner tapered surface that faces inward in the nozzle radial direction and that is inclined to be further away from the nozzle central axis as the inner tapered surface approaches the combustion chamber.

30. The gas turbine combustor according to claim 29,

wherein the inner flow path wall one end portion has the outer tapered surface, and

the nozzle flow path wall has an opposite inclined surface that faces the outer tapered surface and that is inclined to be closer to the nozzle central axis as the opposite inclined surface approaches the nozzle injection port.

31. The gas turbine combustor according to claim 18,

wherein the nozzle flow path forming portion has a nozzle flow path wall that is continuous with the inner peripheral surface of the combustion cylinder,

the seal air flow path forming portion is disposed on a side opposite to the nozzle central axis with respect to the nozzle flow path wall, and

the seal air injection port is open in the nozzle flow path wall and is configured to inject seal air toward the nozzle injection port.