Fuel injector, combustor, gas turbine, and combustor system

Abstract

A fuel injector according to one embodiment of the present invention injects a mixed gas of air and fuel into a combustor liner, the fuel injector comprising an air supply pipe, a swirler, a fuel supply pipe, and a guide flow path part. The air supply pipe has a first injection port communicating with the combustor liner. The swirler is provided to a flow path of the air supply pipe and swirls the air. The fuel supply pipe has a fuel injection part for injecting the fuel into a flow path from the swirler within the air supply pipe to the first injection port. The guide flow path part has a second injection port which surrounds the first injection port and via which an air flow for guiding the mixed gas injected through the first injection port is injected.

Description

Fuel injector, combustor, gas turbine, and combustor system

[0001] The present invention relates to a fuel injector, a combustor, a gas turbine, and a combustor system applicable to fuels such as hydrogen.

[0002] Combustors that burn fuels such as hydrogen mixed with air have been developed. For example, when hydrogen is used as fuel, no carbon dioxide is emitted, and this has attracted attention as a method of curbing global warming.

[0003] Patent Document 1 describes a combustor with multiple burners arranged concentrically to generate tiny diffusion flames. This combustor, also known as a micromix combustor, is equipped with a fuel injector with multiple burners arranged concentrically, each of which consists of an air guide groove and tiny injection holes for injecting hydrogen into the air guide groove. Because the flames of each burner are small, hot spots are suppressed, nitrogen oxides (NOx) are reduced, and flashbacks are prevented, enabling stable combustion.

[0004] Also, combustors with multiple fuel injectors are known. For example, Patent Document 2 describes a hydrogen injection device (fuel injector) that has an inner hydrogen injection conduit inside an outer conduit with swirlers, and generates a hydrogen jet in the same direction as air injected from the outer conduit. Patent Document 3 describes a fuel injector that has a guide member outside a fuel supply pipe that allows air to pass, and a fuel injection hole in the fuel supply pipe that injects fuel into the air passing through the guide member. In Patent Documents 2 and 3, combustors are configured with a plurality of fuel injectors like those described above.

[0005] JP 2017-522533 A JP 2024-508474 A JP 2021-169913 A

[0006] With a structure that provides multiple fuel injectors, as in Patent Documents 2 and 3, it is possible to simplify the structure of the fuel injectors themselves and the fuel flow path compared to, for example, the micro-mix combustor described in Patent Document 1. However, depending on the configuration of the fuel injectors, the flame may spread and the hot spot may become larger, making it difficult to suppress the generation of NOx and achieve stable combustion. For this reason, there is a demand for technology that can stably achieve a small flame with a simple structure.

[0007] In view of the above circumstances, an object of the present invention is to provide a fuel injector, a combustor, a gas turbine, and a combustor system that are capable of stably realizing a small flame with a simple structure.

[0008] To achieve the above object, one aspect of the present invention provides a fuel injector that injects a mixed gas of air and fuel into a combustor liner, and includes an air supply pipe, a swirler, a fuel supply pipe, and a guide flow path. The air supply pipe has a first injection port that communicates with the combustor liner. The swirler is provided in a flow path of the air supply pipe and swirls the air. The fuel supply pipe has a fuel injection port that injects the fuel into a flow path within the air supply pipe from the swirler to the first injection port. The guide flow path has a second injection port that surrounds the first injection port and injects an air flow that guides the mixed gas injected from the first injection port.

[0009] In this fuel injector, fuel is injected from a fuel injection section of the fuel supply pipe into a flow path from a swirler provided in the air supply pipe to a first injection port, and a mixed gas of air and fuel is injected from the first injection port. The fuel injector also has a guide flow path section having a second injection port surrounding the first injection port, and an air flow is injected from the second injection port to guide the mixed gas injected from the first injection port. This makes it possible to achieve a stable small flame with a simple structure.

[0010] A combustor according to one aspect of the present invention includes a combustor liner and a fuel injector that injects a mixed gas of air and fuel into the combustor liner. The fuel injector includes an air supply pipe having a first injection port that communicates with the combustor liner, a swirler that is provided in a flow path of the air supply pipe and swirls the air, a fuel supply pipe having a fuel injection unit that injects the fuel into a flow path within the air supply pipe from the swirler to the first injection port, and a guide flow path unit that surrounds the first injection port and has a second injection port that injects an air flow that guides the mixed gas injected from the first injection port.

[0011] A gas turbine according to one aspect of the present invention includes a combustor and a turbine. The combustor has a combustor liner and a fuel injector that injects a mixed gas of air and fuel into the combustor liner. The turbine is driven by combustion gas from the combustor. The fuel injector has an air supply pipe having a first injection port that communicates with the combustor liner, a swirler that is provided in a flow path of the air supply pipe and swirls the air, a fuel supply pipe having a fuel injection unit that injects the fuel into a flow path within the air supply pipe from the swirler to the first injection port, and a guide flow path unit that surrounds the first injection port and has a second injection port that injects an air flow that guides the mixed gas injected from the first injection port.

[0012] A combustor system according to one aspect of the present invention includes a combustor, a fuel supply line, and a control unit. The combustor has a combustor liner and a fuel injector that injects a mixed gas of air and fuel into the combustor liner. The fuel supply line supplies fuel to the fuel injector. The control unit controls the supply of the fuel to the fuel injector through the fuel supply line. The fuel injector includes an air supply pipe having a first injection port that communicates with the combustor liner, a swirler that is provided in a flow path of the air supply pipe and swirls the air, a fuel supply pipe having a fuel injection unit that injects the fuel into a flow path in the air supply pipe from the swirler to the first injection port, and a guide flow path unit that surrounds the first injection port and has a second injection port that injects an air flow that guides the mixed gas injected from the first injection port.

[0013] As described above, according to the present invention, it is possible to stably realize a small flame with a simple structure. Note that the effects described here are not necessarily limited to those described herein, and any of the effects described in this disclosure may be used.

[0014] FIG. 1 is a schematic diagram showing an example of a configuration of an aircraft gas turbine engine according to a first embodiment of the present invention. FIG. 1 is a schematic diagram showing an example of a configuration of a hydrogen supply line. FIG. 1 is a schematic diagram showing an example of a configuration of a hydrogen combustor including an annular combustor liner. FIG. 2 is a schematic diagram showing an example of a cross-sectional configuration of an annular combustor liner. FIG. 3 is a perspective view showing an example of a configuration of a hydrogen combustor including a box-shaped combustor liner. FIG. 4 is a rear view of the hydrogen combustor shown in FIG. 5. FIG. 5 is a side view of the hydrogen combustor shown in FIG. 5. FIG. 6 is a top view of the hydrogen combustor shown in FIG. 5. FIG. 6 is a cross-sectional view showing an example of an internal configuration of the hydrogen combustor shown in FIG. 5, viewed from above. FIG. 6 is a cross-sectional view showing an example of an internal configuration of the hydrogen combustor shown in FIG. 5, viewed from the front. FIG. 7 is a cross-sectional view showing an example of a configuration of a fuel injector. FIG. 8 is a cross-sectional view showing an example of an internal configuration of the air supply pipe. FIG. 9 is a schematic diagram illustrating the inclination angle of an axial swirler. FIG. 10 is a map showing an example of a temperature distribution around a fuel injector. FIG. 11 is a map showing an example of a flow velocity distribution around a fuel injector. FIG. 12 is a map showing an example of a temperature distribution in a box-shaped combustor liner. FIG. 13 is a map showing another example of a temperature distribution in a box-shaped combustor liner. FIG. 14 is a cross-sectional view showing an example of a configuration of a fuel injector according to a second embodiment. FIG. 1 is a cross-sectional view showing an example configuration of a radial swirler. FIG. 2 is a schematic view showing an example configuration of a support portion of a fuel injector. FIG. 3 is a schematic view showing another example configuration of a fuel injector. FIG. 4 is a schematic view showing another example configuration of a fuel injector. FIG. 5 is a schematic view showing another example configuration of a fuel injector. FIG. 6 is a schematic view showing another example configuration of a fuel injector. FIG. 7 is a schematic view showing another example configuration of a fuel injector. FIG. 8 is a cross-sectional view showing an example configuration of a hydrogen combustor equipped with a water injection nozzle. FIG. 9 is a schematic view showing another example configuration of a fuel injector. FIG. 10 is a schematic view showing another example configuration of a fuel injector. FIG. 11 is a schematic view showing another example configuration of a fuel injector.

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] <First Embodiment> [Configuration of Hydrogen Gas Turbine Engine] Figure 1 is a schematic diagram showing an example of the configuration of an aircraft gas turbine engine according to a first embodiment of the present invention. The aircraft gas turbine engine 10 is a gas turbine engine installed on an aircraft, and is driven by a gas turbine that uses hydrogen as fuel (hydrogen gas turbine). Figure 1 also shows a schematic diagram of a hydrogen combustor system 100 including the aircraft gas turbine engine 10.

[0017] The hydrogen combustor system 100 includes an aircraft gas turbine engine 10, a hydrogen tank 11, a hydrogen supply line 12, and a control unit 13. The aircraft gas turbine engine 10 includes a compressor 14, a hydrogen combustor 15, and a turbine 16. In this embodiment, the aircraft gas turbine engine 10 corresponds to a gas turbine, and the hydrogen combustor system 100 corresponds to a combustor system. The hydrogen combustor 15 corresponds to a combustor, and the hydrogen supply line 12 corresponds to a fuel supply line.

[0018] The aircraft gas turbine engine 10 is an engine that generates propulsion by combusting oxygen in the air with hydrogen stored in a hydrogen tank in a hydrogen combustor 15 and rotating a turbine 16 with a jet of combustion gas. The aircraft gas turbine engine 10 is configured as, for example, a turbofan engine, and the hydrogen combustor 15 functions as a high-pressure combustor mounted on the turbofan engine. However, the aircraft gas turbine engine 10 may be of other types of engines. For example, the present invention can be applied to turboprop engines, turbojet engines, open rotor engines including open fan engines, and the like, that are equipped with hydrogen gas turbines.

[0019] The compressor 14 compresses air taken into the aircraft gas turbine engine 10. The compressor 14 is connected to the turbine 16 via a rotary shaft 17 and is driven by the rotation of the turbine 16 (rotary shaft 17). The specific configuration of the compressor 14 is not limited, and any type of compressor may be used, such as an axial compressor, a centrifugal compressor, or a mixed flow compressor.

[0020] The hydrogen combustor 15 combusts the air compressed by the compressor 14 with hydrogen as fuel, and ejects high-temperature, high-pressure combustion gas. The combustion gas is sent to a turbine 16 located downstream of the hydrogen combustor 15. The specific configuration of the hydrogen combustor 15 will be described in detail later.

[0021] The turbine 16 is driven by the combustion gas from the hydrogen combustor 15. Specifically, the combustion gas serves as a driving source to drive the compressor 14, and the combustion gas is discharged to generate thrust. The turbine 16 is provided with stator vanes that align the direction of the combustion gas and rotor blades that rotate together with the rotary shaft 17. The rotor blades receive the combustion gas via the stator vanes and rotate together with the rotary shaft 17, which in turn drives the compressor 14 to rotate. The combustion gas that passes through the turbine 16 is discharged from a main nozzle at the rear of the aircraft gas turbine engine 10, generating thrust.

[0022] The hydrogen tank 11 is a tank that stores hydrogen as fuel for the hydrogen combustor 15. As the hydrogen tank 11, for example, an insulated container configured to be able to store liquefied hydrogen is used.

[0023] The hydrogen supply line 12 is a supply line that supplies hydrogen stored in the hydrogen tank 11 to the hydrogen combustor 15. Specifically, the hydrogen supply line 12 supplies hydrogen as fuel to a fuel injector, which will be described later. The hydrogen supply line 12 is configured using a hydrogen pump, a shutoff valve (safety valve), a distribution valve, a flow control valve, a vent pipe, pipes connecting each part, and the like.

[0024] 2 is a schematic diagram showing an example of the configuration of the hydrogen supply line 12, illustrating a flow rate adjustment configuration provided in the hydrogen supply line 12. In the example shown in Fig. 2, two shutoff valves Vs1 and Vs2 are provided to shut off the flow path in order from the upstream side, and a high flow rate adjustment valve Vh capable of adjusting a high flow rate and a low flow rate adjustment valve Vl capable of adjusting a low flow rate are provided in parallel between the shutoff valves Vs1 and Vs2.

[0025] 2, a vent pipe Lv1 is connected to a path connecting the upstream shutoff valve Vs1 to the high flow rate control valve Vh and the low flow rate control valve Vl, and a vent pipe Lv2 is connected to a path connecting the high flow rate control valve Vh and the low flow rate control valve Vl to the downstream shutoff valve Vs2. A shutoff valve Vs3 is provided in the vent pipe Lv1, and a shutoff valve Vs4 is provided in the vent pipe Lv2. When hydrogen is supplied, the shutoff valves Vs1 and Vs2 are open, and the shutoff valves Vs3 and Vs4 provided in the vent pipes Lv1 and Lv2 are closed.

[0026] Controlling the flow rate of hydrogen is generally difficult, and it can be difficult to achieve sufficient control accuracy, especially when controlling the flow rate at low flow rates. Therefore, in the hydrogen supply line 12, flow rate control is performed using a low-flow rate flow control valve (Vh) and a high-flow rate flow control valve (Vl) in combination so that hydrogen can be controlled from low to high flow rates. In other words, a dual flow control valve is used, using valves with different adjustment ranges. This makes it possible to control the flow rate of hydrogen more accurately than, for example, when controlling the flow rate using only one flow control valve.

[0027] When the supply of hydrogen is stopped, for example, the shutoff valves Vs1 and Vs2 are closed, and then the shutoff valves Vs3 and Vs4 provided in the vent pipes Lv1 and Lv2 are opened, thereby purging (releasing to the atmosphere) hydrogen remaining in the pipes between the shutoff valves Vs1 and Vs2.

[0028] The control unit 13 is configured using a computer having a CPU (Central Processing Unit) and memory. The control unit 13 controls the operation of the hydrogen combustor 15 by controlling the hydrogen supply line 12. Specifically, the control unit 13 controls the supply of hydrogen to the fuel injector through the hydrogen supply line 12. For example, a Full Authority Digital Engine Control (FADEC) or the like is used as the control unit 13.

[0029] [Configuration of a Hydrogen Combustor with an Annular Combustor Liner] Figure 3 is a schematic diagram showing an example of the configuration of a hydrogen combustor with an annular combustor liner. Figure 4 is a schematic diagram showing an example of the cross-sectional configuration of an annular combustor liner. In the hydrogen combustor 15a shown in Figures 3 and 4, the combustor liner 30 constituting the combustion chamber 31 is annular in shape. The hydrogen combustor 15a is configured as a reverse flow combustor that bends the injection direction of the combustion gas 4 (indicated by the open arrow) and injects it in the opposite direction. This type of hydrogen combustor 15a is a type widely used in aircraft gas turbine engines 10. In Figures 3 and 4, the direction of the central axis C of the hydrogen combustor 15a is defined as the X direction. Furthermore, directions perpendicular to each other in a plane perpendicular to the X direction are defined as the Y direction and the Z direction. Figure 4 is a cross-sectional view taken along the XZ plane including the central axis C.

[0030] The hydrogen combustor 15a includes a combustor chamber 20a, a combustor liner 30a, a fuel injector 40, and an igniter 18. Each component of the hydrogen combustor 15a is constructed using a metal material such as stainless steel so as to withstand the temperature of the combustion gas, but ceramic materials, resin materials such as fiber-reinforced plastic, and the like may also be used.

[0031] Hereinafter, the side from which the hydrogen combustor 15a injects the combustion gas 4 will be referred to as the rear of the hydrogen combustor 15a, and the opposite side will be referred to as the front of the hydrogen combustor 15a. For example, in Figures 3 and 4, the left side of the drawing corresponds to the front of the hydrogen combustor 15a, and the right side corresponds to the rear. Also, Figure 4 is a schematic illustration of a cross section of the hydrogen combustor 15a taken along the central axis C, with one side sandwiched between the central axis C. Therefore, for example, the shape obtained by rotating the cross section shown in Figure 4 around the central axis C can be regarded as the general shape of the hydrogen combustor 15a. Hereinafter, with respect to each part of the hydrogen combustor 15, the side closer to the central axis C will be referred to as the inner side, and the side farther from the central axis C will be referred to as the outer side.

[0032] The combustor chamber 20a is a housing for the hydrogen combustor 15 and houses a combustor liner 30a. As shown in FIG. 4 , the combustor chamber 20 has a double-cylindrical chamber wall 21 that is open at the front and closed at the rear. The front end of the inner chamber wall 21 is located rearward of the front end of the outer chamber wall 21. A compressor 14 that generates compressed air 1 is disposed in front of the combustor chamber 20a, and a turbine 16 is disposed in the space surrounded by the inner chamber wall 21. A flow path for passing the compressed air 1 (indicated by the black arrow) is formed between the combustor chamber 20a and the combustor liner 30a. The shaded areas in FIGS. 3 and 4 function as inlet holes through which the compressed air 1 is introduced.

[0033] The combustor liner 30a forms a combustion chamber 31 in which a mixed gas of hydrogen and air is combusted. As shown in FIG. 4 , the combustor liner 30a has a main partition 32a and a reverse flow partition 32b as partitions 32 surrounding the combustion chamber 31. The main partition 32a has a double cylindrical shape that is open at the front and closed at the rear, and is housed in a space surrounded by the outer and inner chamber walls 21 of the combustor chamber 20. A fuel injector 40 is provided at the rear (bottom) of the main partition 32a. The reverse flow partition 32b has a U-shaped cross section on one side when cut along the central axis C, and has both outer and inner open ends that open rearward. The outer open end is connected to the front of the main partition 32a, and the inner open end forms an injection port 33 of the combustor liner 30a that injects the combustion gas 4. The injection port 33 is arranged to face the turbine 16 surrounded by the inner chamber wall 21 .

[0034] The fuel injectors 40 inject a mixture of air (compressed air 1) and hydrogen 2 into the combustor liner 30a. A plurality of fuel injectors 40 are concentrically arranged in the annular combustor liner 30a. Therefore, the hydrogen combustor 15 is an annular combustor in which the fuel injectors 40 are arranged annularly in a single annular combustor liner 30a. Note that FIG. 3 illustrates the fuel supply pipes 43 of the fuel injectors 40 that supply hydrogen 2. Each fuel supply pipe 43 is connected to, for example, a hydrogen manifold that distributes and supplies hydrogen gas. Note that there may be one or more hydrogen gas supply systems. The configuration of the fuel injectors 40 will be described in detail later.

[0035] The igniter 18 is an ignition device that ignites the mixed gas supplied to the combustor chamber 20 (combustion chamber 31), and is provided so as to penetrate from the outside of the combustor chamber 20a into the combustor liner 30a. As the igniter 18, for example, an ignition plug that generates a spark by applying high voltage is used. There are no limitations on the type or format of the igniter 18, and any ignition device used in a gas turbine or the like can be used.

[0036] 4, in the combustor liner 30a, the flow path of the combustion gas 4 injected forward from the main body partition 32a is bent 180 degrees by the reverse flow partition 32b, and the combustion gas 4 is injected rearward from the injection ports 33. The combustion gas 4 injected from the injection ports 33 collides with the stator blades of the turbine 16. By configuring the hydrogen combustor 15 as a reverse flow combustor in this way, it becomes possible to arrange the turbine 16 in the space surrounded by the combustor liner 30, and the entire gas turbine can be configured compactly.

[0037] The hydrogen combustor 15 may be configured as a forward flow combustor. In this case, a combustor liner 30 is provided, in which a combustion chamber 31 extends in the front-to-rear direction (X direction). A fuel injector 40 is disposed in front of the combustor liner 30, and an injection port 33 is provided in the rear. In a forward flow combustor, the combustion gas 4 impinges linearly on the stator vanes of the turbine 16. By configuring the hydrogen combustor 15 as a forward flow combustor, it is possible to simplify the overall configuration of the gas turbine, for example.

[0038] [Configuration of Hydrogen Combustor Equipped with Box-Shaped Combustor Liner] Figure 5 is a perspective view showing an example configuration of a hydrogen combustor 15 equipped with a box-shaped combustor liner. Figure 6 is a rear view of the hydrogen combustor 15 shown in Figure 5. Figure 7 is a side view of the hydrogen combustor 15 shown in Figure 5. Figure 8 is a top view of the hydrogen combustor 15 shown in Figure 5. Figure 9 is a cross-sectional view showing an example internal configuration of the hydrogen combustor 15 shown in Figure 5 as viewed from above. Figure 10 is a cross-sectional view showing an example internal configuration of the hydrogen combustor 15 shown in Figure 5 as viewed from the front. The cross-sectional views shown in Figures 9 and 10 are taken through the hydrogen combustor 15b along line AA shown in Figure 6 and line BB shown in Figure 8, respectively.

[0039] 5 to 10, the hydrogen combustor 15b has a box-shaped (rectangular parallelepiped) combustor liner 30 that defines a combustion chamber 31. The hydrogen combustor 15b includes a flange portion 25, an inlet duct 27, a combustor chamber 20b, a combustor liner 30b, a fuel injector 40, and an igniter 18. In FIGS. 5 to 10, the X direction is the depth direction of the combustor liner 30b, the Y direction is the left-right direction of the combustor liner 30b, and the Z direction is the up-down direction of the combustor liner 30b.

[0040] The following describes the fuel injectors and combustor liners that make up the hydrogen combustor 15, taking as an example a hydrogen combustor 15b equipped with a box-shaped combustor liner 30b. The hydrogen combustor 15b can also be considered a sector combustor, which is formed by cutting out a portion of a hydrogen combustor 15a equipped with an annular combustor liner 30a shown in Figures 3 and 4 to form a rectangular parallelepiped combustion chamber 31. For example, the sector combustor (hydrogen combustor 15b) differs from the hydrogen combustor 15a in the overall shape of the combustor chamber and combustor liner, but the basic configuration and operation are also applicable to the hydrogen combustor 15a.

[0041] The flange portion 25 is a circular plate member with screw holes formed on its outer periphery, and functions as a fixing member that connects the hydrogen combustor 15b to the downstream flow passage. One main surface of the flange portion 25 serves as a connection surface with the downstream flow passage, and the combustor chamber 20b is fixed to the other main surface. Furthermore, as shown in FIGS. 5 and 9 , the flange portion 25 has a rectangular opening that connects to the combustor liner 30. This opening functions as an injection port 33 that injects the combustion gas 4. Hereinafter, the side where the injection port 33 is provided will be referred to as the front of the hydrogen combustor 15b, and the opposite side will be referred to as the rear.

[0042] The inlet duct 27 is a duct that communicates with the interior of the combustor chamber 20b and introduces the compressed air 1 into the combustor chamber 20b. One end of the inlet duct 27 is connected to the output end of the compressor 14 (not shown), and the other end of the inlet duct 27 is connected to a duct connection portion 28 provided in the combustor chamber 20b. Hereinafter, the inlet duct 27 is connected at an angle with respect to the connection portion between the flange portion 25 and the combustor chamber 20b. In the following, the side on which the inlet duct 27 is provided will be referred to as the upper side of the hydrogen combustor 15b, and the opposite side will be referred to as the lower side.

[0043] The combustor chamber 20b is a housing for the hydrogen combustor 15 and houses the combustor liner 30b. The combustor chamber 20b has an overall rectangular parallelepiped shape that is open forward. The open end of the combustor chamber 20b is larger than the opening (the injection port 33) of the flange portion 25. For example, as shown in FIG. 8 , the combustor chamber 20b is configured by joining a central chamber wall 21a and box-shaped side chamber walls 21b provided on both the left and right sides of the central chamber wall 21a. The space surrounded by the central chamber wall 21a and the two side chamber walls 21b is an approximately rectangular parallelepiped sealed space to which the compressed air 1 is supplied. The front of the top surface of the central chamber wall 21a is open, and a duct connection 28 is provided to cover this opening. The igniter 18 is connected to the top surface of the central chamber wall 21a, rear of the duct connection 28.

[0044] 9 and 10 , the combustor liner 30b is box-shaped and defines a rectangular parallelepiped combustion chamber 31 that is open forward. The combustor liner 30b is fixed to the combustor chamber 20b and the flange portion 25. In this embodiment, the flange portion 25 and the combustor chamber 20b function as base portions for fixing the combustor liner. A flow path for passing the compressed air 1 is formed between the combustor chamber 20b and the combustor liner 30b.

[0045] The combustor liner 30b has a central partition 32c and side partitions 32d as partitions 32 surrounding the combustion chamber 31. As shown in FIG. 9 , the central partition 32c is a metal plate bent into a U-shape and forms the upper, lower, and rear surfaces of the combustor liner 30b. The front of the central partition 32c is connected to the opening of the flange portion 25 to form the injection port 33. The side partitions 32d are metal plates provided on both sides of the central partition 32c and form the side surfaces of the combustor liner 30b. As shown in FIG. 10 , a box-shaped shielding member 34 that blocks the compressed air 1 is provided on the side of the side partition 32d opposite the combustion chamber 31. The provision of the shielding member 34 suppresses the cooling effect of the compressed air 1 on the sides of the combustion chamber 31, thereby achieving a combustion environment similar to that of, for example, an annular combustion chamber 31. Hereinafter, the central partition wall portion 32c and the side partition wall portions 32d may be simply referred to as partition wall portions 32.

[0046] The fuel injectors 40 inject a mixture of air (compressed air 1) and hydrogen 2 into the combustor liner 30b. As shown in Figures 9 and 10, three fuel injectors 40 are arranged side by side in the left-right direction (Y direction) behind the combustor liner 30b. The tip of each fuel injector 40 penetrates the partition 32 (the rear end of the central partition 32c) of the combustor liner 30b and is arranged in the combustion chamber 31. Note that part of the fuel injector 40 (fuel supply pipe 43) and the hydrogen supply line 12 for supplying hydrogen are visible in Figures 5 to 8.

[0047] [Configuration of fuel injector] Figure 11 is a cross-sectional view showing an example of the configuration of a fuel injector. Figure 11A is an enlarged view of the combustor liner 30b and the fuel injector 40 and their surroundings shown in Figure 9, with the flange portion 25 and the inlet duct 27 omitted. Figure 11B is a schematic diagram showing the configuration of the fuel injector 40 shown in Figure 11A. The configuration of the fuel injector 40 will be described below with reference to Figure 11.

[0048] The fuel injector 40 has an air supply pipe 41, a swirler 42, a fuel supply pipe 43, and a guide flow path portion 44. Hereinafter, the central axis of the fuel supply pipe 43 will be referred to as C1. The central axis C1 becomes the injection axis along which the mixed gas 3 of compressed air 1 and hydrogen 2 is injected from the fuel injector 40.

[0049] The air supply pipe 41 is a tubular member that introduces the compressed air 1. Typically, a circular pipe member that is open at both ends is used as the air supply pipe 41. In this embodiment, a fuel supply pipe 43 having a diameter smaller than the inner diameter of the air supply pipe 41 is inserted inside the air supply pipe 41. Therefore, a flow path for the compressed air 1 is formed between the air supply pipe 41 and the fuel supply pipe 43. For this reason, it can be said that the air supply pipe 41 functions as a cover (shroud cover) that forms a flow path around the fuel supply pipe 43.

[0050] 11B , the air supply pipe 41 has a first inlet 50 and a first jet orifice 51. The first inlet 50 is an open end formed at the rear of the air supply pipe 41, and compressed air 1 passing through a flow path between the combustor chamber 20b and the combustor liner 30b enters the first inlet 50. The first jet orifice 51 is an open end formed at the front of the air supply pipe 41, and communicates with the combustor liner 30b. As will be described later, hydrogen as fuel is injected from the fuel supply pipe 43 into the air supply pipe 41. Therefore, a mixed gas 3 of compressed air 1 and hydrogen 2 is injected from the first jet orifice 51.

[0051] The swirler 42 is provided in the flow path of the air supply pipe 41 and swirls the compressed air 1. The swirler 42, also called a swirler, has blades that swirl the air. The provision of the swirler 42 generates swirling air (a swirling vortex), enabling efficient mixing of hydrogen and air. The swirler 42 also adjusts the flow rate of the compressed air 1 and exhibits a flame-holding function that maintains the flame. For example, by appropriately setting the angle of the blades 52 of the swirler 42, the swirling air and flame-holding function can be strengthened and the downstream velocity of the combustion gas 4 can be slowed.

[0052] FIG. 12 is a cross-sectional view showing an example of the internal configuration of the air supply pipe 41. FIG. 12 is a cross-sectional view of the air supply pipe 41 cut along a plane tangent to the outer periphery of the fuel supply pipe 43, and shows the cross-sectional structure of the swirler 42. In this embodiment, an axial swirler that swirls the compressed air 1 in a flow path along the axial direction of the air supply pipe 41 is used as the swirler 42. Here, the flow path along the axial direction of the air supply pipe 41 refers to a flow path that flows the compressed air 1 in the axial direction (X direction) of the air supply pipe 41, and is a cylindrical flow path formed between the air supply pipe 41 and the fuel supply pipe 43. The axial swirler is also called an axial swirler.

[0053] As shown in FIG. 12 , the swirler 42 (axial swirler) has a plurality of blades 52. In the axial swirler, the blades 52 are components that obliquely block the axial flow path of the air supply pipe 41. For example, the blades 52 are spiral plate members arranged along the outer circumferential surface of the fuel supply pipe 43. The blades 52 are fixed to at least one of the outer circumferential surface of the fuel supply pipe 43 and the inner circumferential surface of the air supply pipe 41. Alternatively, a modularized swirler 42 may be fitted between the air supply pipe 41 and the fuel supply pipe 43. Here, four blades 52 are provided at 90-degree intervals on the outer circumferential surface of the fuel supply pipe 43, but the number of blades 52 is not limited.

[0054] 13 is a schematic diagram illustrating the inclination angle of the axial swirler. Fig. 13 shows a development of the cylindrical outer peripheral surface of the fuel supply pipe 43. The black circles in the figure represent fuel injection holes 55 (described later), and the thick black lines represent the blades 52 of the swirler 42.

[0055] Here, the angle between the direction in which the compressed air 1 passes (the left-right direction in the drawing) and the blade 52 is referred to as the inclination angle θw of the blade 52. For example, if the blade 52 is arranged parallel to the passing direction, the inclination angle θw is 0. In general, the greater the inclination angle θw of the blade 52, the stronger the swirling air becomes, and the slower the flow velocity downstream of the swirler 42 becomes. The inclination angle θw is set appropriately so that a flame of a desired size can be formed, for example.

[0056] Returning to Figure 11, the fuel supply pipe 43 is a tubular member that introduces hydrogen 2 supplied from the hydrogen supply line 12. A circular pipe member that is open at the rear and closed at the front is used as the fuel supply pipe 43. The diameter of the fuel supply pipe 43 is smaller than the inner diameter of the air supply pipe 41, and the length of the fuel supply pipe 43 is longer than that of the air supply pipe 41. The fuel supply pipe 43 is arranged coaxially inside the air supply pipe 41 so that the front ends of the fuel supply pipe 43 and the air supply pipe 41 are aligned. The flow path of the hydrogen 2 inside the fuel supply pipe 43 extends forward of the swirler 42.

[0057] The fuel supply pipe 43 has a fuel inlet 53 and a fuel injection unit 54. The fuel inlet 53 is an open end at the rear of the fuel supply pipe 43, and is connected to the hydrogen supply line 12 so that hydrogen 2 is injected into the fuel inlet 53. A screw fastening mechanism 70, which will be described later, is connected to the rear of the fuel supply pipe 43 so as to surround the fuel inlet 53.

[0058] The fuel injection unit 54 injects hydrogen 2 into a flow path from the swirler 42 to the first injection port 51 in the air supply pipe 41. The flow path from the swirler 42 to the first injection port 51 is a flow path formed between the inlet of the swirler 42 and the first injection port 51, and includes a flow path inside the swirler 42. This allows hydrogen 2 to be injected into the swirling flow of compressed air 1, enabling diffusion premixing in which the compressed air 1 and hydrogen 2 are mixed while diffusing. In this way, the fuel injector 40 functions as a combustor that partially mixes the compressed air 1 (oxygen) and the fuel hydrogen 2 and burns them while diffusing them.

[0059] The fuel injection unit 54 is configured to inject the hydrogen 2 at an injection pressure lower than the pressure of the hydrogen 2 in the fuel supply pipe 43. The pressure of the hydrogen 2 in the fuel supply pipe 43 is, for example, the pressure of the hydrogen 2 supplied from the fuel inlet 53 (the inlet pressure as seen from the fuel injection unit 54). The injection pressure is the pressure of the hydrogen 2 injected from the fuel injection unit 54. Note that the injection pressure does not necessarily coincide with the pressure in the air supply pipe 41 (the outlet pressure as seen from the fuel injection unit 54).

[0060] A structure that makes the injection pressure lower than the inlet pressure is generally a structure that generates a contracted flow. For example, the fuel injection unit 54 has a structure that forms a throttled flow path that is narrower than the inner diameter of the fuel supply pipe 43, and that this throttled flow path connects to a wider flow path (the flow path inside the air supply pipe 41) on the downstream side. With this structure, a contracted flow occurs in the throttled flow path in the fuel injection unit 54, and a pressure reduction function that lowers the pressure of the hydrogen 2 is achieved.

[0061] By providing the fuel injection unit 54 with a pressure reduction function, it is possible to easily supply fuel at a constant flow rate by utilizing a choked state. The choked state is a state in which the injection velocity U at the fuel injection unit 54 is M=1 at the outlet throat. Here, M is the Mach number, and M=U / a, where a is the speed of sound. Therefore, the choked state is a state in which the injection velocity U reaches the speed of sound. In this case, the flow rate of the fuel (hydrogen 2) injected from the fuel injection unit 54 is constant regardless of the pressure ratio (outlet pressure / inlet pressure) before and after the fuel injection unit 54. Therefore, even if, for example, the inlet pressure on the fuel supply pipe 43 side or the outlet pressure (pressure of compressed air 1) on the air supply pipe 41 side changes, it is possible to inject hydrogen 2 at a constant flow rate in the choked state.

[0062] 11A and 11B, in this embodiment, the fuel supply pipe 43 is disposed inside the air supply pipe 41, and the fuel injection unit 54 injects hydrogen 2 into the air supply pipe 41 from inside the air supply pipe 41. In other words, a fuel flow path and a fuel injection mechanism are provided inside the air supply pipe 41. This makes it possible to configure the entire fuel injector 40 compactly, for example.

[0063] In this embodiment, the fuel injection portion 54 is a plurality of through holes provided in the fuel supply pipe 43. Hereinafter, the through holes that become the fuel injection portion 54 will be referred to as fuel injection holes 55. The planar shape of the fuel injection holes 55 is typically circular, but injection holes having, for example, an elliptical shape or a slit shape may also be formed. Furthermore, fuel injection holes 55 of different shapes and sizes may also be provided.

[0064] In this embodiment, the fuel injection holes 55 are formed as through-holes of the same shape and size. The fuel injection holes 55 are formed in the side wall of the fuel supply pipe 43 so as to communicate with the flow path of hydrogen 2 inside the fuel supply pipe 43. This makes it possible to easily provide injection ports (fuel injection units 54) for hydrogen 2 in the fuel supply pipe 43. The fuel supply pipe 43 also functions as a throttle flow path that generates a contracted flow. The fuel injection holes 55 are provided on the forward side of the fuel supply pipe 43, between the outlet of the swirler 42 and the first injection ports 51. Therefore, the hydrogen 2 is injected downstream of the swirler 42. Note that a configuration in which hydrogen 2 is injected inside the swirler 42 (see FIG. 22 ) is also possible.

[0065] 11A and 11B , in this embodiment, the fuel injection holes 55 are provided at equal intervals around the central axis C1 of the fuel supply pipe 43. That is, the fuel injection holes 55 are evenly arranged in the circumferential direction of the fuel supply pipe 43. Therefore, the hydrogen 2 is injected radially and uniformly in the circumferential direction of the fuel supply pipe 43. That is, the hydrogen 2 is injected uniformly all around the flow path of the compressed air 1 in the air supply pipe 41.

[0066] The fuel supply pipe 43 is provided with eight fuel injection holes 55, for example, spaced at 45-degree intervals (see FIG. 13 , etc.). The number and arrangement of the fuel injection holes 55 are not limited, but in order to suppress unevenness in the density of the hydrogen 2, it is preferable to arrange two or more fuel injection holes 55 at equal intervals.

[0067] The fuel injection holes 55 are micropores with a relatively small diameter. Specifically, the diameter of the fuel injection holes 55 is preferably set to 0.1 mm or more and 0.5 mm or less. This makes it possible to sufficiently suppress the flow rate (injection amount) of hydrogen 2 injected from each fuel injection hole 55 compared to a hole diameter of, for example, about 1 mm. This has the effect of suppressing the growth of the flame.

[0068] The fuel injector 40 is configured so that the hydrogen 2 injected from the fuel injection holes 55 (fuel injection section 54) into the air supply pipe 41 collides with the inner wall of the air supply pipe 41. By the hydrogen 2 colliding with the inner wall of the air supply pipe 41, the hydrogen 2 is further diffused, and diffusion premixing with the compressed air 1 is promoted.

[0069] The positions and orientations of the multiple fuel injection holes 55 are set so that an extension of the injection direction of the hydrogen 2 intersects with the inner wall of the air supply pipe 41. Furthermore, the distance between the fuel supply pipe 43 and the air supply pipe 41 (the flow path width of the compressed air 1) is set to a size that allows the hydrogen 2 injected from the fuel injection holes 55 to reach the inner wall. Parameters such as the position and orientation of the fuel injection holes 55 and the flow path width of the compressed air 1 may be calculated by a method such as simulation, for example.

[0070] The position of the fuel injection hole 55 is set so that the injected hydrogen 2 can collide with the inner wall even if it is blown forward by the influence of the compressed air 1. For example, the fuel injection hole 55 is provided at a position rearward from the first injection port 51 by a distance approximately equal to the width of the flow path of the compressed air 1.

[0071] The fuel injection holes 55 are typically formed so as to be perpendicular to the central axis C1. In this case, the injection direction of the hydrogen 2 is perpendicular to the flow path of the compressed air 1, and the injected hydrogen 2 can reach the inner wall at the extreme distance, enabling efficient diffusion premixing. The fuel injection holes 55 may also be formed so as to be inclined with respect to the central axis C1. For example, an inclined through-hole is formed so that the hydrogen 2 is injected obliquely forward from the fuel supply pipe 43. The angle between the central axis C1 and the fuel injection holes 55 is set, for example, in the range of 45 degrees to 90 degrees, with 0 degrees being the angle when the fuel injection holes 55 are parallel to the central axis C1 and facing forward.

[0072] The width of the flow path for the compressed air 1 is preferably set to 1 mm or more and 10 mm or less. By narrowing the flow path in this way, the hydrogen 2 is more likely to collide with the inner wall. Even if the hydrogen 2 does not collide, the narrow flow path makes it possible to sufficiently mix the compressed air 1 and hydrogen 2.

[0073] In this embodiment, the air supply pipe 41, the swirler 42, and the fuel supply pipe 43 are integrated into a module to form a mixed gas injection unit 46 that injects the mixed gas 3. The mixed gas injection unit 46 can be regarded as an injection nozzle of the mixed gas 3 in the fuel injector 40.

[0074] The outside of the mixed gas injection unit 46 is formed by an air supply pipe 41 that serves as a shroud cover, and inside thereof is provided a swirler 42 (axial swirler) with flame stabilization and swirling functions. A fuel supply pipe 43, to which hydrogen 2 is supplied, is disposed coaxially with the air supply pipe 41 in the center of the mixed gas injection unit 46. Hydrogen 2 is injected from fuel injection holes 55 (fuel injection unit 54) of the fuel supply pipe 43 into the flow path of compressed air 1. This achieves rapid diffusion premixing of the hydrogen 2 and compressed air 1 in the mixed gas injection unit 46, and a mixed gas 3 of hydrogen 2 and compressed air 1 is injected from a first annular injection port 51 formed at the front.

[0075] The guide flow path section 44 is a mechanism for generating an air flow 5 that guides the mixed gas 3. The guide flow path section 44 has a cover section 56, a second inlet port 57, and a second outlet port 58.

[0076] The cover portion 56 is a member that surrounds the outer periphery 47 of the mixed gas injection portion 46 so as to form an air flow path along the outer periphery 47 of the mixed gas injection portion 46. The outer periphery 47 of the mixed gas injection portion 46 is the outer periphery surface of the air supply pipe 41. The cover portion 56 is disposed inside the head portion (the rear end of the central partition portion 32c of the combustor liner 30b) of the combustor liner 30b that forms the combustion chamber 31. The cover portion 56 functions as a fuel injector cover to protect the metal surface of the mixed gas injection portion 46 from flames in the event of flashback.

[0077] A circular pipe member is typically used as the cover portion 56. The inner diameter of the cover portion 56 is larger than the outer diameter of the air supply pipe 41, and the length of the cover portion 56 in the front-rear direction (X direction) is the same as that of the air supply pipe 41. The cover portion 56 is disposed so that its front end is aligned with that of the air supply pipe 41 (fuel supply pipe 43). In this manner, an air flow path is formed between the shroud cover (air supply pipe 41) of the mixed gas injection unit 46 and the cover for the fuel injector (cover portion 56), allowing compressed air to be supplied from outside the combustor liner 30b. The rear end of this air flow path is the second inlet port 57, and the front end is the second injection port 58.

[0078] The second inlet 57 is an annular open end formed to surround the first inlet 50 of the air supply pipe 41. The compressed air 1 passing through the flow path between the combustor chamber 20b and the combustor liner 30b enters the second inlet 57. The second jet port 58 is an annular open end formed to surround the first jet port 51 of the air supply pipe 41. The compressed air 1 entering from the second inlet 57 is jetted from the second jet port 58.

[0079] As described above, the guide flow path section 44 has the second injection port 58 which surrounds the first injection port 51 and injects the air flow 5 which guides the mixed gas 3 injected from the first injection port 51. As a result, the mixed gas 3 and its combustion gas 4 are guided forward by the air flow 5 which is injected forward so as to surround the mixed gas 3. In other words, the air flow 5 serves to guide the flame and exerts the effect of suppressing the spread of the flame.

[0080] As described above, in the guide channel section 44 according to this embodiment, the second injection port 58 is formed between the outer circumferential portion 47 of the mixed gas injection section 46 and the cover section 56. In other words, the guide channel section 44 can be said to be a mechanism that generates the air flow 5 for guiding the mixed gas 3 by utilizing the cover section 56 that protects the mixed gas injection section 46. This makes it possible to easily generate the air flow 5 without using a complex structure.

[0081] The diameter of the cover portion 56 is preferably set to be equal to or greater than one-third and equal to or less than two-thirds of the height of the combustor liner. Here, the height of the combustor liner refers to the height of the passage portion (combustion chamber 31) of the combustor liner, and is, for example, the minimum distance between the partition portions 32 facing each other across the fuel injection portion 54 forward of the fuel injector 40 in a cross section parallel to the injection axis (center axis C1) of the fuel injector 40. In the box-shaped combustor liner 30b, three fuel injectors 40 are arranged side by side in the horizontal direction (Y direction). In this case, the distance between the central partition portions 32c in the vertical direction (X direction) corresponds to the height of the combustor liner 30b. In the annular-shaped combustor liner 30a described with reference to FIGS. 3 and 4, the height corresponds to the distance between the central partition portions 32c in the radial direction of the annulus.

[0082] Setting the diameter of the cover portion 56 within the above range allows the distance from the fuel injector 40 to the partition portion 32 to be relatively large. This makes it possible to sufficiently prevent the partition portion 32 from being exposed to flames and being damaged. In addition, a sufficient space is created for the air flow 5 to guide the mixed gas 3, making it possible to properly guide the mixed gas 3.

[0083] The diameters of the first injection nozzle 51 and the second injection nozzle 58 may be specified relative to the diameter of the cover portion 56 (hereinafter referred to as the cover diameter). For example, the diameter of the first injection nozzle 51 is preferably set to be 2 / 5 or more and 4 / 5 or less of the cover diameter. By setting the diameter of the first injection nozzle 51 to be 4 / 5 or less of the cover diameter, the spread of flames can be suppressed while maintaining the protective performance of the cover portion 56. Furthermore, by setting the diameter of the first injection nozzle 51 to be 2 / 5 or more of the cover diameter, an appropriate amount of air can be introduced, and since the air supply pipe 41 is not too small, manufacturing and maintenance are simplified. Furthermore, the diameter of the second injection nozzle 58 is preferably set to be 2 / 5 or more and 4 / 5 or less of the cover diameter, provided that it is larger than the diameter of the first injection nozzle 51. By setting the diameter of the second injection nozzle 58 to be 4 / 5 or less of the cover diameter, a sufficient thickness of the cover portion can be ensured. Furthermore, by setting the diameter of the second injection port 58 to be 2 / 5 or more of the diameter of the cover, the size of the first injection port 51 can be ensured.

[0084] In this embodiment, the cover portion 56 and the mixed gas injection portion 46 are configured to be detachable from each other. For example, no fixing mechanism or the like is provided for fixing the cover portion 56 and the mixed gas injection portion 46 together, and the fuel injector 40 is configured by fixing each portion individually with the mixed gas injection portion 46 inserted into the cover portion 56. Note that a mechanism (screws, fixing jigs, etc.) for detachably fixing the cover portion 56 and the mixed gas injection portion 46 may be provided. Furthermore, a positioning mechanism may be provided for axial alignment and longitudinal positioning of the cover portion 56 and the mixed gas injection portion 46.

[0085] 11A and 11B , the cover portion 56 is fixed to the partition portion 32 (central partition portion 32c) of the combustor liner 30b. A circular opening 35 for passing the mixed gas injection unit 46 is provided at the rear end of the central partition portion 32c. The diameter of the opening 35 is set, for example, to be equal to or larger than the inner diameter and equal to or smaller than the outer diameter of the cover portion 56. The cover portion 56 is disposed in front of the opening 35 (inside the central partition portion 32c) so that its center coincides with that of the opening 35.

[0086] Furthermore, the mixed gas injection unit 46 is fixed to the combustor chamber 20b (base portion) while being loaded into the cover portion 56. In other words, the mixed gas injection unit 46 is inserted into the cover portion 56 attached to the combustor liner 30b to form the fuel injection unit 54. With this configuration, the mixed gas injection unit 46 can be easily removed from the cover portion 56, for example, by releasing the fixed portion between the mixed gas injection unit 46 and the combustor chamber 20b.

[0087] 11A , a screw mechanism 70 is connected to the fuel supply pipe 43 of the mixed gas injection unit 46. The screw mechanism 70 is provided on the opposite side of the fuel supply pipe 43 from the fuel injection unit 54, and fixes the fuel supply pipe 43 to the combustor chamber 20b (base portion).

[0088] The screw fastening mechanism 70 has a supply pipe connecting portion 71 and a supply line connecting portion 72. The supply pipe connecting portion 71 is a cylindrical member with a thread formed on the front side, and is fixed to the rear of the fuel supply pipe 43. The supply line connecting portion 72 is a joint member connected to the piping that constitutes the hydrogen supply line 12, and is fixed to the rear of the supply pipe connecting portion 71. A flare joint or the like is used as the supply line connecting portion 72.

[0089] The supply pipe connecting portion 71 is screwed into the insertion hole 24 provided at the rear end of the combustor chamber 20. The insertion hole 24 is configured to allow the air supply pipe 41 to pass through. Therefore, the mixed gas injection unit 46 is inserted from the rear of the combustor chamber 20b and the supply pipe connecting portion 71 is threaded into the insertion hole 24, thereby attaching the mixed gas injection unit 46 and the cover portion 56. In this way, because the mixed gas injection unit 46 is fastened to the combustor chamber 20b by screws, it is easy to attach and detach, and its structure allows for good maintenance.

[0090] [Configuration of Combustor Liner] Here, the configuration of each part of the combustor liner 30b will be described. The combustor liner 30b has one or more dilution holes 36, cooling holes 37, and air introduction holes 38. These holes are through holes that communicate with the combustion chamber 31 of the combustor liner 30b.

[0091] One or more dilution holes 36 are provided in the central partition wall portion 32c and introduce dilution air 6 that dilutes the combustion gas 4 produced by combustion of the mixed gas 3 so as to interfere with the combustion gas 4. Specifically, the dilution holes 36 are provided, for example, at positions where the combustion gas 4 and the dilution air 6 collide, that is, at positions where the dilution air 6 is in phase with the fuel injectors 40. The diameter of the dilution holes 36 is set to be relatively large, for example, several mm, in order to introduce the dilution air 6.

[0092] 11A , in the box-shaped combustor liner 30b, the dilution holes 36 are provided so that their positions in the Y direction coincide with the central axes C of the fuel injectors 40. Here, one dilution hole 36 is provided on the upper side and one on the lower side of the central partition wall portion 32c corresponding to each of the three fuel injectors 40. Note that the number of dilution holes 36 provided corresponding to each fuel injector 40 is not limited, and for example, one dilution hole 36 may be provided, or two or more dilution holes 36 may be provided.

[0093] The mixed gas 3 injected from the fuel injector 40 is ignited by the igniter 18 and injected as combustion gas 4 toward the injection port 33 of the combustor liner 30b. At this time, the combustion gas 4 interferes with the dilution air 6 ejected from the dilution holes 36. This reduces the temperature of the flame downstream of the dilution holes 36, suppressing the expansion of the high-temperature region (see FIG. 16, etc.).

[0094] The cooling holes 37 are minute through-holes provided to cool the partition wall portion 32 of the combustor liner 30. The diameter of the cooling holes 37 is set to, for example, 1 mm or less (e.g., 0.5 mm). For example, in the combustor liner 30b, a plurality of cooling holes 37 are formed at a predetermined aperture ratio around the fuel injectors 40 and in the portion through which the combustion gas 4 passes. The aperture ratio represents, for example, the area of ​​the cooling holes 37 and is proportional to the airflow rate of the cooling air. Specifically, the cooling holes 37 are formed over the entire upper, rear, and lower surfaces of the central partition wall portion 32c. Generally, if the airflow rate used as cooling air is high, the airflow rate used for combustion (e.g., the flow rate of the compressed air 1 entering the fuel injectors 40) decreases, affecting the combustion state. Therefore, the aperture ratio of the cooling holes 37 is set, for example, based on the balance between the airflow rate used for combustion and the airflow rate required for cooling.

[0095] The air introduction holes 38 are through-holes provided separately from the dilution holes 36 to introduce compressed air 1 into the combustion chamber 31. In this respect, the air introduction holes 38 can also be considered second air holes. For example, the positions of the air introduction holes 38 in the Y direction are set so as not to be in phase with the fuel injectors 40. In FIG. 11A , two air introduction holes 38 are provided side by side in the Y direction between the dilution holes 36 and each fuel injector 40. The positions of each air introduction hole 38 in the Y direction are set to be midway between the central fuel injector 40 and the adjacent fuel injectors 40. This allows the compressed air 1 to be introduced upstream of the dilution holes 36 without blocking the combustion gas 4. This prevents, for example, an extreme drop in pressure around the fuel injectors 40, making it possible to achieve an appropriate combustion environment.

[0096] [Combustion Operation in Hydrogen Combustor and Functions of Each Part] In the hydrogen combustor 15b, compressed air 1 is first supplied to the inlet duct 27. With compressed air 1 being supplied, hydrogen 2 (hydrogen gas) is supplied at a predetermined pressure to the fuel supply pipe 43 of the fuel injector 40.

[0097] In the fuel injector 40, hydrogen 2 is injected from the fuel injection holes 55 into the compressed air 1 that has entered the air supply pipe 41 and passed through the swirler 42, thereby achieving diffuse premixing of the compressed air 1 and hydrogen 2. As a result, the mixed gas 3 is injected from the first injection holes 51.

[0098] The mixed gas 3 injected into the combustor liner 30b is ignited by the igniter 18, forming a flame made of the combustion gas 4. When compressed air 1 is supplied, an air flow 5 that guides the mixed gas 3 is constantly injected from the second injection port 58. Therefore, the combustion gas 4 forms a flame guided by the air flow.

[0099] The supply of hydrogen 2 to the fuel supply pipe 43 is controlled by a control unit 13 (see FIG. 1 ) that controls the hydrogen supply line 12. Specifically, the control unit 13 controls the supply of hydrogen 2 to the fuel injector 40 through the hydrogen supply line 12 so that the hydrogen 2 can be injected from the fuel injection hole 55 in a choked state.

[0100] For example, a choked state is achieved by setting the pressure ratio (outlet pressure / inlet pressure) before and after the fuel injection hole 55 to a critical pressure ratio (0.528) or less. In this case, the outlet pressure is the pressure of the compressed air in the air supply pipe 41 (back pressure as seen from the fuel supply pipe 43), and the inlet pressure is the pressure of the hydrogen 2 in the fuel supply pipe 43 (supply pressure from the hydrogen supply line 12).

[0101] The control unit 13 controls the supply pressure from the hydrogen supply line 12 so that the above relationship is established. The supply pressure is controlled by, for example, adjusting a flow rate control valve (see FIG. 2 ) or a pressure control valve that constitutes the hydrogen supply line 12. The supply pressure is appropriately set to a pressure that allows a choked state to be achieved and does not damage the hydrogen supply line 12 or the hydrogen combustor 15. Injecting hydrogen 2 from the fuel injection holes 55 in a choked state in this way makes it possible to keep the flow rate (injection amount) of hydrogen 2 constant, thereby stabilizing the flame.

[0102] Furthermore, the fuel injection holes 55 have a pressure reduction function that reduces the injection pressure of the hydrogen 2 below the inlet pressure (supply pressure) on the fuel supply pipe 43 side. This can also be said to be a structure that generates pressure loss. This function makes it possible to suppress the effect on the inlet pressure of fluctuations in the outlet pressure on the air supply pipe 41 side, for example. This makes it possible to stably maintain a choked state, for example.

[0103] The injection amount of hydrogen 2 in a choked state increases as the diameter of the injection hole increases. For example, even if the total injection amount in a hydrogen combustor is the same, if the injection amount from one injection hole is large, the flame size will increase, making it more likely that hot spots, which are sources of NOx, will occur. In response to this, by suppressing the injection amount from one injection hole and dispersing the total injection amount, it is possible to avoid unnecessary increases in flame size.

[0104] From this perspective, in this embodiment, the fuel injection holes 55 are formed as fine holes, for example, with a size of 0.1 mm or more and 0.5 mm or less. This makes it possible to sufficiently suppress the injection amount from each fuel injection hole 55. In this case, for example, by increasing the number of fuel injectors 40, it becomes possible to distribute and supply the required total injection amount. This makes it possible to stably achieve a small flame with reduced hot spots and the like.

[0105] The injection amount may also be adjusted by adding fuel injection holes 55. By making the fuel injection holes 55 fine holes as described above, the injection amount can be adjusted more precisely by adding fuel injection holes 55 compared to, for example, when the fuel injection holes 55 are relatively large. This makes it possible to adjust the total injection amount with high precision.

[0106] Furthermore, because the fuel injection holes 55 are minute holes, it is possible to sufficiently suppress the effect on the inlet pressure due to changes in the outlet pressure, etc. This increases the stability of the choked state in the fuel injection holes 55, and it is possible to sufficiently improve the stability of the flame. In this way, in the fuel injector 40, the minute fuel injection holes 55 make it possible to control the hydrogen flow rate to be constant at the design point, and stable flame formation is possible.

[0107] From the fuel supply pipe 43, hydrogen 2 is injected evenly in the circumferential direction from fuel injection holes 55 formed at equal intervals in the circumferential direction. This makes it possible to uniformly mix the hydrogen 2 and compressed air 1 in the flow path of the air supply pipe 41. As a result, uneven concentration of hydrogen 2 in the mixed gas 3 is avoided, and stable flame formation is possible.

[0108] A swirler 42 is provided on the flow path of the air supply pipe 41. For example, the swirling vortex can be strengthened by appropriately setting the inclination angle θw (see FIG. 13) of the blades 52 of the swirler 42. This reduces the injection speed of the mixed gas 3, making it possible to improve the ignition performance of the igniter 18, for example. It also makes it possible to reduce the flow speed of the combustion gas 4. This contributes to the suppression of detonation, as described below.

[0109] In general, hydrogen 2 is a fuel with a very high combustion speed compared to other fuels such as kerosene. Therefore, when the flow velocity of the mixed gas 3 containing hydrogen 2 is high, there is a possibility that the mixed gas 3 will ignite and generate combustion gas 4 traveling at nearly the speed of sound. Tests of a hydrogen combustor conducted by the present inventor have revealed that when the injection velocity of the mixed gas 3 is sufficiently high, a noise called detonation occurs when the combustion gas 4 reaches the speed of sound.

[0110] In order to suppress detonation, it is effective to reduce the flow velocity of the combustion gas 4. On the other hand, if the flow velocity of the combustion gas 4 is too slow, flashback or the like may occur. From this perspective, in this embodiment, the inclination angle θw of the blade portion 52 is set to be equal to or greater than 45° and equal to or less than 60° with respect to the passing direction of the compressed air 1. This makes it possible to improve ignition performance and suppress detonation while suppressing flashback.

[0111] The direction in which the hydrogen 2 is injected from the fuel injection holes 55 of the fuel supply pipe 43 is perpendicular to the compressed air 1. This promotes mixing of the compressed air 1 and the hydrogen 2. In particular, because the hydrogen 2 is injected toward the inner wall of the air supply pipe 41, the collision of the hydrogen 2 with the inner wall further promotes mixing of the compressed air 1 flowing from the swirler 42 with the hydrogen 2. Note that even when the hydrogen 2 is injected obliquely with respect to the compressed air 1, proper mixing can be achieved by the action of a swirling vortex, etc.

[0112] For example, in a choked state, the injection pressure of the hydrogen 2 is greater than the air pressure (outlet pressure) at the outlet of the swirler 42. For example, when the outlet pressure of the compressed air 1 at the air supply pipe 41 is 5 bar, a choked state is achieved if the inlet pressure on the fuel supply pipe 43 side is approximately 13 bar. In this case, due to the conditions of an isentropic flow convergent nozzle, the injection pressure of the hydrogen 2 is approximately 6.9 bar, which is greater than the pressure of the compressed air 1. This makes it possible for the hydrogen 2 to collide with the inner wall of the air supply pipe 41, making it possible to sufficiently promote mixing of the hydrogen 2 and the compressed air 1.

[0113] In the fuel injector 40, the mixture gas injection unit 46 that injects the mixture gas 3 is inserted into a cover unit 56 attached to the combustor liner 30b. In this state, a flow path for passing compressed air 1 is formed between the cover unit 56 and the outer periphery 47 (air supply pipe 41) of the mixture gas injection unit 46 inside the cover unit 56. As a result, a second injection port 58 that injects an air flow 5 that guides the mixture gas 3 is formed around the first injection port 51 that injects the mixture gas 3. This air flow 5 rectifies the mixture gas 3 so that it advances forward, making it possible to suppress radial diffusion of the mixture gas 3. As a result, the spread of the combustion gas 4 resulting from the combustion of the mixture gas 3, i.e., the flame, is suppressed, making it possible to achieve a stable small flame.

[0114] The combustion gas 4 injected forward interferes with the dilution air 6 injected from the dilution holes 36. This reduces the mainstream velocity of the combustion gas 4 and lowers the exhaust gas temperature. Furthermore, for example, at the time of ignition, the combustion gas 4 collides with the dilution air 6, thereby reducing the flow velocity of the combustion gas 4. This makes it possible to prevent the occurrence of detonation. It also makes it possible to prevent the expansion of high-temperature areas such as hot spots, thereby suppressing the generation of NOx.

[0115] [Simulation of Combustion Operation in a Hydrogen Combustor] Figure 14 is a map showing an example of temperature distribution around a fuel injector. Figure 15 is a map showing an example of flow velocity distribution around a fuel injector. Figures 14 and 15 show simulation results of temperature distribution and flow velocity distribution in a model of a hydrogen combustor 15b equipped with a box-shaped combustor liner 30b. Computational Fluid Dynamics (CFD) analysis was used for the simulation. In this model, the internal structure of the fuel supply pipe 43 and other components are omitted as appropriate. Note that the dotted lines in each figure correspond to the front end of the fuel injector 40.

[0116] In Figure 15, it can be seen that the provision of a swirler 42 in the flow path of the air supply pipe 41 changes the direction of travel of the compressed air 1 within the flow path, generating a swirling vortex. Hydrogen 2 is injected from the fuel injection holes 55 perpendicular to the flow path of the air supply pipe 41 into this swirling vortex. It can also be seen that the mixed gas 3 is dispersed and injected so as to spread out in the radial direction. As shown in Figures 14 and 15, the mixed gas 3 injected from the air supply pipe 41 becomes combustion gas 4, and its temperature and velocity increase. Note that the temperature and velocity of the combustion gas 4 decrease toward the outside.

[0117] 15, compressed air 1 also enters the flow path between the cover part 56 and the air supply pipe 41 from the rear and is sprayed forward as air flow 5. Note that a positioning protrusion 59 is provided on the upper side of the flow path from which air flow 5 is sprayed in the figure. This causes changes in flow velocity and temperature to be observed.

[0118] The airflow 5, which is injected to surround the flow of the mixed gas 3, interferes with the mixed gas 3 diffusing in the radial direction. As a result, the mixed gas 3 is rectified so that it moves forward. As shown in Figure 14, the distribution of the high-temperature combustion gas 4 is also rectified by the airflow 5, resulting in a gently spreading flow. In other words, it can be seen that the situation in which the combustion gas 4 diffuses in the radial direction and the flame expands is suppressed, and the size of the flame is reduced.

[0119] Fig. 16 is a map showing an example of the temperature distribution in a box-shaped combustor liner. Fig. 17 is a map showing another example of the temperature distribution in a box-shaped combustor liner. The maps shown in Fig. 16 and Fig. 17 are temperature distributions obtained from a CFD analysis of a model of a hydrogen combustor 15b equipped with a box-shaped combustor liner 30b.

[0120] Figures 16A, 16B, and 16C are respectively a map in an XZ cross section passing through the central fuel injector 40, a map in a YZ cross section passing through the dilution holes 36, and a map in a YZ cross section directly below the inlet duct 27. In Figure 16A, line B representing the cross section of Figure 16B and line C representing the cross section of Figure 16C are shown by dotted lines. The cross sections of Figures 17A, 17B, and 17C are similar to the cross sections of Figures 16A, 16B, and 16C.

[0121] In the simulation shown in FIG. 16 , the mixed gas 3 is injected from three fuel injectors 40 provided in the combustor liner 30 b. In FIG. 16 , the diameter of the fuel injection holes 55 is set to 0.35 mm, and a constant flow rate is injected assuming a choked state. In the simulation shown in FIG. 17 , the mixed gas 3 is injected from only the central fuel injector 40 of the three fuel injectors 40 provided in the combustor liner 30 b. In FIG. 17 , the diameter of the fuel injection holes 55 is set to 1 mm, and a constant flow rate is injected assuming a choked state. The total injection amount injected into the combustor liner 30 b is set to the same value in both FIG. 16 and FIG. 17 . Therefore, the injection amount from each fuel injector 40 in FIG. 16 is 1 / 3 of the injection amount from the central fuel injector 40 in FIG. 17 .

[0122] First, referring to FIG. 17 , an example using only one fuel injector 40 will be described. In this case, as shown in FIG. 17A , the flame spreads to the upper and lower surfaces of the combustor liner 30b, forming a relatively large flame. Furthermore, the flame that spreads vertically collides with the dilution air 6 from the dilution holes 36, causing a drop in temperature downstream of the dilution holes 36. Because the upstream flame is large, the temperature downstream of the dilution holes 36 is also relatively high, and the flame size is large. Because the flame spreads easily, there is a possibility of, for example, detonation or damage to the combustor liner 30b. Furthermore, as shown in FIGS. 17A and 17B , as the flame expands, the size of the hot spot where the flame temperature is high also increases. This may result in an increase in the amount of NOx generated.

[0123] Next, referring to FIG. 16 , an example in which hydrogen 2 is dispersedly injected using three fuel injectors 40 will be described. In FIG. 16A , the combustion gas 4 injected from the fuel injector 40 forms a long, narrow flame without spreading radially (here, vertically), and the overall flame size is significantly smaller than in FIG. 17A . Furthermore, the dilution air 6 injected from the dilution holes 36 interferes with the combustion gas 4. Therefore, as shown in FIG. 16C , the temperature of the combustion gas 4 is sufficiently lower in the region downstream of the dilution holes 36 than in FIG. 17C . Furthermore, as shown in FIG. 16B , by using three fuel injectors 40, the flame is dispersed in the Y direction, but the size of each flame is small, and no hot spots, such as those seen in FIG. 17B , are generated.

[0124] The reason why the flame from the fuel injector 40 is small in size is thought to be due to the generation of the airflow 5 that guides the mixed gas 3, as well as the dispersion of the injection amount by using the fuel injection holes 55 as fine holes, resulting in operation in a choked state. It is also possible to distribute the injection amount among three fuel injectors 40 without reducing the size of the fuel injection holes 55. In this case, in order to limit the injection amount, it is necessary to reduce the number of fuel injection holes 55 or reduce the injection amount at a lower pressure without operating in a choked state. This may result in a decrease in flame stability due to, for example, uneven distribution of the mixed gas 3 or instability in the total injection amount.

[0125] In contrast, as shown in Figure 16, a method using hydrogen injection from fine holes can avoid the above-mentioned instability and generate a stable small flame. Even under the conditions shown in Figure 17, the mixed gas 3 is guided by the air flow 5, making it possible to reduce the size of the flame compared to when no air flow 5 is generated. Therefore, depending on the size, application, operating conditions, etc. of the combustor, it is possible to use injection holes of about 1 mm, as shown in Figure 17.

[0126] As described above, in the fuel injector 40 according to this embodiment, hydrogen 2 as fuel is injected from the fuel injection section 54 (fuel injection holes 55) of the fuel supply pipe 43 into a flow path from the swirler 42 provided in the air supply pipe 41 to the first injection nozzle 51, and the mixed gas 3 of compressed air 1 and hydrogen 2 is injected from the first injection nozzle 51. The fuel injector 40 also has a guide flow path section 44 (cover section 56) having a second injection nozzle 58 surrounding the first injection nozzle 51, and the air flow 5 is injected from the second injection nozzle 58 to guide the mixed gas 3 injected from the first injection nozzle 51. This makes it possible to stably produce a small flame with a simple structure.

[0127] For example, a micromix combustor, which has countless burners with tiny injection holes, can suppress hot spots in the flame that cause NOx emissions, thereby achieving low NOx, and can also prevent backfires, ensuring stable combustion. However, it requires a complex fuel flow path structure and a ring-shaped module with hundreds of tiny injection holes, which is thought to pose issues in terms of maintainability, manufacturing costs, and reliability.

[0128] In this embodiment, the mixed gas injection unit 46 that injects the mixed gas 3 is configured by a module that integrates the fuel supply pipe 43, the air supply pipe 41, and the swirler 42. A cover 56 that surrounds the mixed gas injection unit 46 forms a flow path inside the cover 56, and an air flow 5 that guides the mixed gas 3 is injected from this flow path. Despite this relatively simple structure, the fuel injector 40 is able to stably generate a small flame by generating the air flow 5.

[0129] Furthermore, by making the fuel injection holes 55 of the fuel injector 40 finer and operating them in a choked state, it is possible to sufficiently suppress the spread of flames. This makes it possible to prevent localized hot spots and achieve stable combustion. Furthermore, preventing hot spots not only protects the combustor equipment, but also makes it possible to suppress the generation of NOx and prevent detonation.

[0130] Second Embodiment A fuel injector according to a second embodiment of the present invention will be described. In the following description, the description of the same configurations and operations as those of the fuel injector described in the above embodiment will be omitted or simplified.

[0131] Fig. 18 is a cross-sectional view showing an example of the configuration of a fuel injector according to the second embodiment. As shown in Fig. 18, a fuel injector 40a is provided in the box-shaped combustor chamber 20b described in the above embodiment. Of course, the fuel injector 40a can also be mounted and used in the annular combustor chamber 20a shown in Fig. 3 and the like. Fig. 18A is an enlarged view of the combustor liner 30b and the periphery of the fuel injector 40a, and Fig. 18B is a schematic view showing the configuration of the fuel injector 40 shown in Fig. 18A.

[0132] The fuel injector 40a includes an air supply pipe 41a, a swirler 42a, a fuel supply pipe 43a, and a guide flow path portion 44a. In this embodiment, a radial swirler that swirls the compressed air 1 in a flow path along the radial direction of the air supply pipe 41a is used as the swirler 42a. The radial swirler is a swirler that swirls the compressed air 1 traveling along the radial direction of the central axis C1, for example.

[0133] 19 is a cross-sectional view showing an example of the configuration of a radial swirler. As shown in FIG. 19 , the swirler 42a includes a connecting plate 65, a bottom plate 66, and a plurality of blades 67. The connecting plate 65 is an annular plate member connected to the rear end of the air supply pipe 41a, and the outer and inner diameters of the connecting plate 65 are set to be the same as the outer and inner diameters of the air supply pipe 41a. The bottom plate 66 is an annular plate member disposed opposite the connecting plate 65, and the outer diameter of the bottom plate 66 is set to be the same as the outer diameter of the air supply pipe 41a. The inner diameter of the bottom plate 66 is set to be the same as the outer diameter of the fuel supply pipe 43a, and the fuel supply pipe 43a is inserted into an opening of the bottom plate 66.

[0134] The plurality of blades 67 are plate-like members arranged radially between the connecting plate 65 and the bottom plate 66. Each blade 67 is arranged so as to be inclined at a predetermined angle relative to the radial direction of the central axis C1. In addition, an inlet 68 for admitting the compressed air 1 is formed between each blade 67. That is, the swirler 42a (radial swirler) has the inlet 68 through which air enters from the radial direction.

[0135] The swirler 42a may be formed to fit inside the air supply pipe 41a. In this case, the compressed air 1 can be introduced into the swirler 42a by forming a slit or the like on the outer periphery of the air supply pipe 41a to allow the compressed air 1 to pass through. Other than this, the specific configuration and mounting method of the swirler 42a are not limited.

[0136] As a result, the compressed air 1 entering the swirler 42a travels along the blades 67 and collides with the outer wall of the fuel supply pipe 43a. This causes the compressed air 1 to form a swirling vortex while entering the flow path of the air supply pipe 41a and flow along the axial flow direction. Even when a radial swirler is used in this way, generating a swirling vortex can promote mixing of the hydrogen 2 and the compressed air 1 and reduce the injection speed of the mixed gas 3, thereby providing a flame-stabilizing function. Furthermore, adjusting the angle of the blades 67 of the radial swirler can strengthen the swirling vortex, improving ignition performance and suppressing detonation.

[0137] 18A and 18B , because the compressed air 1 needs to be injected from the radial direction, the fuel injector 40a (mixed gas injection unit 46) equipped with a swirler 42a is provided outside the head (the rear end of the central partition wall 32c) of the combustor liner 30b. In this case, the outer periphery of the mixed gas injection unit 46 is not exposed to flames, so there is no need to provide a cover or the like as described in the above embodiment. However, a support unit 60 is provided to support the mixed gas injection unit 46 (air supply pipe 41a) on the combustor liner 30b. In this embodiment, the support unit 60 functions as a guide flow path unit 44a.

[0138] FIG. 20 is a schematic diagram showing an example configuration of the support portion 60 of the fuel injector 40a. FIG. 20 is a schematic plan view of the combustor liner 30b as viewed from the rear. As shown in FIG. 20, a circular opening 35 is provided at the rear end of the central partition wall portion 32c to connect the mixed gas injection portion 46 to the combustion chamber 31. The diameter of the opening 35 is set to be larger than the diameter of the air supply pipe 41a. The support portion 60 is configured by arranging multiple support members 61 at equal intervals around the opening 35. The support members 61 are, for example, members with a fan-shaped planar shape when viewed from the front-rear direction (X direction) and surround and support the cylindrical air supply pipe 41a. Here, three support members 61 are provided at intervals of 120 degrees.

[0139] Between the support members 61, the opening 35 of the combustor liner 30b is exposed. This exposed portion serves as the second injection port 58 that injects the airflow 5 that guides the mixed gas 3. In this manner, in the present embodiment, the support part 60 is attached to the combustor liner 30b as a press for fixing the mixed gas injection unit 46, and the support part 60 forms the second injection port 58 that surrounds the first injection port 51 that injects the mixed gas 3. The airflow 5 that straightens the flame is injected from the second injection port 58. As a result, even in a configuration that uses a radial swirler, it is possible to inject the airflow 5, and a small flame can be stably produced.

[0140] <Other Embodiments> The present invention is not limited to the above-described embodiment, and various other embodiments can be realized.

[0141] The fuel injector 40b shown in FIG. 21 is a variable mechanism injector configured to vary the inclination angle (swirler angle) of the vanes 52 of the swirler 42. Here, a swirler angle variable mechanism 75 is attached to the fuel injector 40b equipped with an axial swirler. For example, a plurality of vanes 52 made of flat plate members are radially arranged on the outer periphery of the fuel supply pipe 43. Each vane 52 is configured to be rotatable around a rotation axis along the radial direction, and the swirler angle of each vane 52 is adjusted by the variable mechanism 75. The configuration of the swirler 42 and the variable mechanism 75 is not limited, and a configuration that allows the swirler angle of a radial swirler to be adjusted may be used, for example. By making the swirler angle adjustable, the strength of the swirling vortex can be adjusted, thereby controlling the flow velocity of the combustion gas 4.

[0142] 22 is a swirler injection type injector configured such that the fuel supply pipe 43 injects hydrogen 2 from inside the swirler 42. Here, the fuel supply pipe 43 is provided with fuel injection pipes 76 that communicate with the flow path of the hydrogen 2. The fuel injection pipes 76 are provided inside the swirler 42, protruding radially from the circumferential direction of the fuel supply pipe 43, and inject hydrogen 2 from their tips. The fuel injection pipes 76 function as the fuel injection unit 54. This allows the hydrogen 2 to collide with the inner wall of the air supply pipe 41, facilitating mixing with the compressed air 1.

[0143] The fuel injector 40d shown in FIG. 23 is a microstructure injector in which the fuel injection portion 54 is constructed using a material having a microstructure. For example, a metamaterial material having a microstructure formed thereon is used as the fuel injection portion 54. For example, the fuel injection portion 54 is constructed using a porous film or porous material having micropores of about 0.1 mm in diameter. The fuel injection portion 54 may also be constructed using additive manufacturing technology such as a 3D printer. In this way, it is possible to construct fine fuel injection holes for the injection holes or the entire injector by utilizing additive manufacturing technology or metamaterial manufacturing technology in addition to manufacturing by machining.

[0144] The fuel injector 40e shown in FIG. 24 is an integrated injector in which the air supply pipe 41 and the cover portion 56 are integrated. In the fuel injector 40e, no gap serving as a flow path is formed between the air supply pipe 41 and the cover portion 56. In this case, for example, a plurality of internal flow paths 77 are formed inside the cover portion 56 along the axial direction. The internal flow paths 77 are flow paths that axially penetrate the side wall of the cover portion 56, and the airflow 5 is injected through the internal flow paths 77. In this case, the front end of the internal flow path 77 functions as the second injection port 58. Alternatively, a flow path for injecting the airflow 5 may be formed by forming a groove along the axial direction on the inner periphery of the cover portion 56.

[0145] The fuel injector 40f shown in Figure 25 is a dual-swirler injector in which an air flow path is formed with an outer swirler 78 that surrounds the outer periphery of the air supply pipe 41. The outer swirler 78 is provided, for example, between the cover portion 56 and the air supply pipe 41. Alternatively, a tubular member or the like that forms the air flow path including the outer swirler 78 may be provided separately from the cover portion 56. The compressed air 1 that passes through the outer swirler 78 is injected as an air flow 5 that guides the mixed gas 3. This makes it possible to adjust, for example, the injection speed of the air flow 5 and thereby adjust the spread of the flame.

[0146] 26 is an external injection type injector that injects hydrogen 2 from the outside of an air supply pipe 41. The fuel injector 40g has multiple external fuel supply pipes 80, an air supply pipe 41, and a module cover 81. Each external fuel supply pipe 80 is connected to an annular fuel manifold 82 that distributes hydrogen 2.

[0147] The multiple outer fuel supply pipes 80 are tubular members that form a flow path for hydrogen 2, and are arranged at equal intervals to surround the air supply pipe 41. The rear ends of the outer fuel supply pipes 80 are connected to a fuel manifold 82, and the front ends are closed. A fuel injection flow path 83 that connects the interiors of the outer fuel supply pipes 80 and the air supply pipe 41 is formed between the outer fuel supply pipes 80 and the air supply pipe 41. The fuel injection flow path 83 may be formed by connecting through holes provided in the side walls of the pipes, or may be formed by connecting the interiors of the pipes with fine tubes or the like. The fuel injection flow path 83 is an example of the fuel injection unit 54.

[0148] In this way, in the fuel injector 40g, the multiple outer fuel supply pipes 80 are arranged outside the air supply pipe 41. Furthermore, the fuel injection flow passages 83 (fuel injection units 54) provided in each outer fuel supply pipe 80 inject hydrogen 2 into the air supply pipe 41 from outside the air supply pipe 41. Even when hydrogen 2 is injected from the outside in this way, premixing with compressed air 1 is possible within the air supply pipe 41.

[0149] As shown on the left side of Figure 26, the module cover 81 is a tubular member that surrounds the module consisting of the air supply pipe 41 and multiple outer fuel supply pipes 80, and functions as a protective member that protects the module from flames. Furthermore, a gap surrounded by the outer fuel supply pipe 80 and the air supply pipe 41 is formed inside the module cover 81. This gap functions as a flow path for the compressed air 1. Therefore, a second injection port 58 that injects air flow 5 that guides the mixed gas 3 is formed at the front end of the module cover 81. This makes it possible to suppress the spread of flames.

[0150] The fuel injector 40h shown in Fig. 27 is an internal / external injection type injector that injects hydrogen 2 from both the outside and the inside of the air supply pipe 41. The fuel injector 40h has a configuration in which an inner fuel supply pipe 84 is provided in addition to the configuration of the fuel injector 40g shown in Fig. 26. The inner fuel supply pipe 84 corresponds to the fuel supply pipe 43 that is arranged inside the air supply pipe 41 described in the above embodiment.

[0151] The fuel injection holes 55 of the inner fuel supply pipe 84 and the fuel injection passages 83 of the outer fuel supply pipe 80 may be positioned to face each other. In this case, the hydrogen 2 injected from the inside and outside interfere with each other, making it possible to sufficiently promote mixing with the compressed air 1. The fuel injection holes 55 and the fuel injection passages 83 may be positioned alternately. In this case, the fuel injection holes 55 and the fuel injection passages 83 both function as the fuel injection units 54.

[0152] 27 , fuel is supplied to the outer fuel supply pipe 80 from a fuel manifold 82, and fuel is supplied to the inner fuel supply pipe 84 from a hydrogen supply line 12 that is separate from the fuel manifold 82. This makes it possible to individually control the supply of hydrogen 2 from the outer fuel supply pipe 80 and the inner fuel supply pipe 84. For example, fuel control is possible by switching between the inner fuel supply pipe 84 as a primary fuel system and the outer fuel supply pipe 80 as a secondary fuel system. This makes it possible to easily adjust the output of the hydrogen combustor according to operating conditions, etc.

[0153] The fuel injector 40i shown in Figure 28 is another example of an external injection type injector that injects hydrogen 2 from outside the air supply pipe 41. The fuel injector 40i has an outer flow path section 85 that forms a flow path for hydrogen 2 outside the air supply pipe 41. The outer flow path section 85 has a structure in which, for example, tubular members with closed ends are arranged at equal intervals around the air supply pipe 41. Hydrogen 2 is supplied to the outer flow path section 85 from the fuel supply pipe 43 arranged inside the air supply pipe 41 via a connecting flow path 86 that passes through the inside of the swirler 42. In addition, a fuel injection flow path 83 that communicates with the inside of the air supply pipe 41 and injects hydrogen 2 is provided in front of the outer flow path section 85.

[0154] In this way, in the fuel injector 40i, hydrogen 2 is injected from outside the air supply pipe 41 by utilizing the fuel supply pipe 43 arranged inside the air supply pipe 41. This allows the injector configuration to be simpler than, for example, the configuration shown in FIG. 26 . Furthermore, by passing the connecting flow path 86 through the inside of the swirler 42, it is expected that the generation of a swirling vortex will be promoted. Note that the outer flow path portion 85 is surrounded by a module cover (not shown) as in, for example, FIG. 26 , and a second injection port 58 is formed at the front end of the module cover to inject the air flow 5 that guides the mixed gas 3.

[0155] Fig. 29 is a cross-sectional view showing an example of the configuration of a hydrogen combustor equipped with a water injection nozzle. The hydrogen combustor 15c shown in Fig. 29 has a configuration in which a water injection nozzle 39 is added to the hydrogen combustor 15b (see Fig. 10, etc.) described in the above embodiment.

[0156] The water injection nozzle 39 is a nozzle that injects water 7 (water or steam). For example, a spray nozzle or the like is used as the water injection nozzle 39. The water injection nozzle 39 is arranged so that its tip is directed toward the flame (combustion gas 4) in the combustion chamber 31. The orientation of the water injection nozzle 39 is not particularly limited, but is typically set so as to be perpendicular to the central axis C1 of the fuel injector 40a.

[0157] 29, the water injection nozzle 39 is inserted into an attachment hole provided on the upper surface of the combustor chamber 20b. The tip of the water injection nozzle 39 penetrates the partition 32 (the upper surface of the central partition 32c) of the combustor liner 30b and is disposed in the combustion chamber 31. The installation position of the water injection nozzle 39 is not limited, and the position in the front-rear direction (X direction), for example, can be set arbitrarily.

[0158] Water 7 is sprayed from the tip of the water spray nozzle 39. The water 7 may be liquid water dispersed in a mist or may be steam. By spraying water or steam onto the flame in this way, it is possible to lower the flame temperature. This makes it possible to suppress the occurrence of hot spots and achieve low NOx emissions.

[0159] The fuel injector described so far achieves a small flame by making the fuel injection holes minute and devising the air flow. This not only protects the combustor, but also prevents localized hot spots and suppresses the generation of NOx. Furthermore, the fuel injector described above is a combustor that partially mixes compressed air 1 and hydrogen 2 and burns them while diffusing, and because the mixed gas 3 is generated while diffusing, it is designed to be less susceptible to flashback (backfire).

[0160] On the other hand, in the above-described fuel injector, as shown in FIG. 11B, for example, the space where the mixed gas 3 is generated is located in front (downstream) of the swirler 42 provided inside the air supply pipe 41, and there is a risk of flashback occurring within the fuel injector. In particular, in a hydrogen combustor, flashback is likely to occur due to the rapid reactivity of hydrogen 2. Below, with reference to FIGS. 30 and 31, a fuel injector having a structure for further reducing the risk of flashback will be described.

[0161] Fig. 30 is a schematic diagram showing another example of the configuration of a fuel injector. A fuel injector 40j shown in Fig. 30 has an air supply pipe 41, a swirler 42, a fuel supply pipe 43, a guide flow path portion 44 (cover portion 56), and an air intake portion 90. A fuel injection portion 54 provided in the fuel supply pipe 43 has a plurality of first fuel injection holes 55a and a plurality of second fuel injection holes 55b.

[0162] The structure of fuel injector 40j is, for example, a structure in which an air intake portion 90 is provided in fuel injector 40 shown in Fig. 11B, and a plurality of first fuel injection holes 55a and a plurality of second fuel injection holes 55b are provided instead of the plurality of fuel injection holes 55. Note that in Fig. 30, the cross-sectional areas of air supply pipe 41, fuel supply pipe 43, and cover portion 56 are shown by dotted areas.

[0163] 30 , in fuel injector 40j, fuel supply pipe 43 is disposed inside air supply pipe 41. Therefore, air supply pipe 41 functions as a shroud cover that forms a flow path around fuel supply pipe 43. In addition, air supply pipe 41 is disposed inside cover portion 56. Therefore, cover portion 56 functions as a protective cover that protects mixed gas injection portion 46 consisting of air supply pipe 41, swirler 42, and fuel supply pipe 43. In addition, cover portion 56 forms guide flow path portion 44 that flows air outside air supply pipe 41.

[0164] The air intake section 90 allows air that passes through the air supply pipe 41 and flows into the guide flow path section 44 to flow into the air supply pipe 41 downstream of the swirler 42. In other words, the air intake section 90 is structured to take in air from the outside to the inside of the air supply pipe 41 (shroud cover), and the air outlet position is set downstream of the swirler 42. This allows mixed gas 3 of hydrogen 2 injected from the first fuel injection holes 55a (described later) and swirled compressed air 1 coming out of the swirler 42 to be efficiently pushed downstream.

[0165] In the example shown in Figure 30, the air intake 90 is a slit 91 that penetrates the outer periphery 47 of the air supply pipe 41. The slit 91 is a through groove that is configured to penetrate into the air supply pipe 41 downstream of the swirler 42. The air supply pipe 41 is provided with a plurality of slits 91 at equal intervals around the central axis C1. The slits 91 are configured, for example, so that the inner outlet is located further downstream than the outer inlet. This allows the compressed air 1 to flow out diagonally forward inside the air supply pipe 41, as shown in Figure 30.

[0166] The specific structure of the slit 91 is not limited. For example, a through groove parallel to the central axis C1 may be formed along the outer periphery 47 of the air supply pipe 41, or a through groove may be formed in a spiral shape. Also, while Figure 30 illustrates the slit 91 inclined with respect to the central axis C1, a slit perpendicular to the central axis C1 (parallel to the radial direction) may also be formed.

[0167] The plurality of first fuel injection holes 55a are provided in the fuel supply pipe 43 and inject fuel (hydrogen 2) into the air supply pipe 41. In other words, the first fuel injection holes 55a are through holes provided in the fuel supply pipe 43 facing the flow path inside the air supply pipe 41. This allows the mixed gas 3 to be generated in the air supply pipe 41.

[0168] Here, the multiple first fuel injection holes 55a are through-holes provided in the side surface of the fuel supply pipe 43 at an angle with respect to the central axis C1 of the fuel supply pipe 43, and are arranged at equal intervals around the central axis C1. Inclined with respect to the central axis C1 means that the extension direction of the through-holes is not parallel to or perpendicular to the central axis C1. As shown in FIG. 30 , the first fuel injection holes 55a are typically configured so that their outer outlets are located further downstream than their inner inlets of the fuel supply pipe 43. This allows hydrogen 2 to flow out obliquely forward inside the air supply pipe 41.

[0169] The inclination angle of each first fuel injection hole 55a with respect to the central axis C1 is preferably 45° to 90°. Here, the inclination angle of each first fuel injection hole 55a is the smaller of the angles between the extending direction of each first fuel injection hole 55a and the central axis C1 in a cross section including the central axis C1, for example.

[0170] 11, each first fuel injection hole 55a may be formed along the radial direction of the fuel supply pipe 43, perpendicular to the central axis C1 (i.e., the inclination angle may be 90°). Also, a through hole formed obliquely with respect to the central axis C1 and a through hole formed in the radial direction may be combined.

[0171] The plurality of second fuel injection holes 55b are provided in the fuel supply pipe 43 and inject fuel (hydrogen-2) into the combustor liner. In other words, the second fuel injection holes 55b are through-holes provided in the fuel supply pipe 43 facing the combustion chamber of the combustor liner (for example, the combustion chamber 31 of the combustor liner 30b in FIG. 11A ) rather than in the flow path inside the air supply pipe 41. This allows hydrogen-2 to be added in the combustion chamber 31 downstream of the air supply pipe 41.

[0172] Here, the multiple second fuel injection holes 55b are through holes provided in the end 48 of the fuel supply pipe 43 that faces the combustor liner, and are arranged at equal intervals around the central axis C1. For example, the fuel supply pipe 43 is a straight pipe with the end 48 that faces the combustor liner closed. The multiple second fuel injection holes 55b are formed in this end 48 in a concentric pattern centered on the central axis C1. The extension direction of the second fuel injection holes 55b is typically set parallel to the central axis C1.

[0173] The configuration of the second fuel injection holes 55b is not limited. For example, each second fuel injection hole 55b may be formed along a direction inclined with respect to the central axis C1. In this case, through holes that inject fuel (hydrogen 2) may be formed so as to radiate from the central axis C1, or through holes that inject fuel so as to converge toward the central axis C1. Furthermore, through holes that are parallel to the central axis C1 and through holes that are inclined with respect to the central axis C1 may be combined.

[0174] The first fuel injection holes 55a and the second fuel injection holes 55b are micropores with a relatively small diameter, similar to the fuel injection holes 55 described with reference to Fig. 11B etc. Specifically, the diameters of the first fuel injection holes 55a and the second fuel injection holes 55b are preferably set to 0.1 mm or more and 0.5 mm or less. This makes it possible to sufficiently suppress the flow rate (injection amount) of hydrogen 2 injected from each injection hole, thereby suppressing the growth of the flame.

[0175] Furthermore, from the viewpoint of suppressing the injection amount and suppressing the increase in flame, it is more preferable that the diameter of the first fuel injection holes 55 a and the second fuel injection holes 55 b be 0.4 mm or less. On the other hand, from the viewpoint of ensuring processing accuracy and preventing clogging, it is more preferable that the diameter of the first fuel injection holes 55 a and the second fuel injection holes 55 b be 0.2 mm or more. In addition, the diameter and number of the first fuel injection holes 55 a and the second fuel injection holes 55 b are not limited, and the diameter and number of each injection hole can be set independently using, for example, simulations or the like.

[0176] Next, the operation of the fuel injector 40j will be described. As shown in Figure 30, the fuel injector 40j has an air inlet (first inlet 50) for the air supply pipe 41 on the inner diameter side, and an air inlet (second inlet 57) for the cover part 56 (guide flow path part 44) on the outer diameter side. Compressed air 1 flows in from these two inlets 50 and 57. In addition, hydrogen 2 is supplied to the fuel supply pipe 43 at a predetermined pressure.

[0177] The air supply pipe 41 is provided with a swirler 42 that swirls the compressed air 1 in an axial direction along the central axis C1 or in a radial direction perpendicular to the central axis C1 (see FIGS. 11B and 18B ). The swirler 42 performs the functions of flame stabilization and promoting mixing of the compressed air 1 and hydrogen 2.

[0178] At the outlet of the flow path of the swirler 42, fuel (hydrogen 2) is injected from first fuel injection holes 55a that are evenly spaced diagonally on the side of the fuel supply pipe 43. As a result, a mixed gas 3 (hereinafter referred to as first mixed gas 3a) of compressed air 1 and hydrogen 2 is formed in the space downstream of the swirler 42 inside the air supply pipe 41. At this time, the compressed air 1 is swirling air, and the hydrogen 2 is injected obliquely in the axial direction, which promotes the formation of the first mixed gas 3a.

[0179] Furthermore, a slit 91 is provided on the outer circumferential portion 47 of the air supply pipe 41 as an air intake portion 90. As a result, compressed air 1 is further supplied from the outside to the space downstream of the swirler 42 within the air supply pipe 41, where the first mixed gas 3a is formed. As a result, the first mixed gas 3a is pushed downstream (in front of the fuel injector 40j) by the compressed air 1 supplied from the air intake portion 90 (here, the slit 91).

[0180] In this way, the air intake section 90 exerts the function of pushing the first mixed gas 3a in the air supply pipe 41 downstream by utilizing the compressed air 1 flowing through the flow path (guide flow path section 44) between the air supply pipe 41 and the cover section 56. This allows the first mixed gas 3a to flow further downstream compared to, for example, a case in which the air intake section 90 is not provided. As a result, it becomes possible to shift the ignition position further downstream.

[0181] 30, by arranging the first fuel injection holes 55a at an angle, the hydrogen 2 is injected downstream. This also has the effect of causing the first mixed gas 3a to flow downstream. Furthermore, since the air intake 90 supplies the compressed air 1 from the outer periphery of the air supply pipe 41, the mixing of the hydrogen 2 and the compressed air 1 can be further promoted.

[0182] The first mixed gas 3a is pushed out by compressed air 1 from the air intake 90 (slit 91) and injected from the outlet (first injection port 51) of the air supply pipe 41. The first mixed gas 3a injected from the first injection port 51 is mixed with fuel (hydrogen 2) injected from the second fuel injection hole 55b provided at the end 48 of the fuel supply pipe 43. As a result, in the space downstream of the fuel injector 40j, a mixed gas 3 (hereinafter referred to as second mixed gas 3b) in which hydrogen 2 is further mixed with the first mixed gas 3a is formed. The second mixed gas 3b is ignited by an ignition device such as a spark plug, and combustion occurs.

[0183] In this way, the fuel injector 40j is provided with the first fuel injection hole 55a and the second fuel injection hole 55b downstream of the first fuel injection hole 55a for injecting hydrogen 2, so that hydrogen 2 is supplied in stages. In this way, the premixed region is moved further downstream by gradually adding hydrogen 2.

[0184] Of the compressed air 1 passing through the flow path between the cover portion 56 and the air supply pipe 41, the compressed air 1 that does not flow into the air intake portion 90 is injected from the second injection port 58 as the air flow 5. This air flow 5 guides the second mixed gas 3b. As a result, a flame guided by the air flow 5 can be formed, similar to the other fuel injectors described above.

[0185] As described above, in the fuel injector 40j shown in Fig. 30, the air intake 90 is provided, so that the mixed gas space (premixing region where the mixed gas 3 is formed) can be generated further downstream. This makes it possible to shift the ignition position further downstream, and to sufficiently suppress the occurrence of flashback.

[0186] Furthermore, the fuel injector 40j injects fuel (hydrogen 2) in two directions, from the first fuel injection hole 55a and the second fuel injection hole 55b. This allows the fuel and air to be mixed slowly, rather than being suddenly sprayed into the air. As a result, stable ignition is possible, which contributes to stable combustion.

[0187] Figure 31 is a schematic diagram showing another example of the configuration of a fuel injector. Fuel injector 40k shown in Figure 31 differs from fuel injector 40j shown in Figure 30 in the configuration of the air intake section 90. Fuel injector 40k has a swirler 92 as the air intake section 90. Here, the swirler 42 provided in the air supply pipe 41 will be referred to as the first swirler 42, and the swirler 92 that serves as the air intake section 90 will be referred to as the second swirler 92. The second swirler 92 corresponds to the other swirler.

[0188] The second swirler 92 swirls the air that passes through the outer periphery 47 of the air supply pipe 41 and flows from the guide flow path portion 44 to the air supply pipe 41. Specifically, the second swirler 92 has a flow path that connects the outside and inside of the air supply pipe 41 and swirl blades that swirl the compressed air passing through the flow path. By providing the second swirler 92, swirling air can be supplied from the outside of the air supply pipe 41.

[0189] 31, the second swirler 92 is a radial swirler that swirls air in a flow path along the radial direction of the air supply pipe 41. The basic configuration of the radial swirler is similar to that of the swirler 42a described with reference to, for example, FIGS.

[0190] For example, as shown in Fig. 19, a swirler having a radial flow path is connected to the air supply pipe 41 downstream of the first swirler 42. Note that while Fig. 31 illustrates the second swirler 92 so that it fits within the thickness of the air supply pipe 41, the second swirler 92 may protrude from the outer or inner periphery, for example. The second swirler 92 may also be configured as a separate member, or may be formed integrally with the air supply pipe 41 by processing it.

[0191] By providing the second swirler 92 in this manner, it is possible to further promote mixing of the first mixed gas 3a. In addition, the radial swirling air can push the first mixed gas 3a downstream while sufficiently diffusing it. This makes it possible to shift the ignition position further downstream, as in the case of Figure 30, and to sufficiently suppress the occurrence of flashback.

[0192] In the above embodiment, the case where the cover portion 56 is fixed to the partition portion 32 (central partition portion 32c) surrounding the combustion chamber 31 has been described. However, the present invention is not limited to this, and the cover portion 56 may be configured to be rotatable about the central axis C1, taking into consideration thermal expansion and the like. This allows the cover portion 56 to rotate 360°, which makes it possible to easily replace a detachable unit (mixed gas injection unit 46) including, for example, the air supply pipe 41, the swirler 42, and the fuel supply pipe 43.

[0193] The fuel injector 401 shown in Figure 32 has a rotatable cover portion 56a. Here, an example is shown in which the mixed gas injection portion 46 shown in Figure 30 is used as a detachable unit inside the cover portion 56a. Note that the configuration of the mixed gas injection portion 46 is not limited, and other configurations, such as the mixed gas injection portion 46 shown in Figure 11B, may be used.

[0194] The cover portion 56a is a generally cylindrical member and has a flange portion 64 that protrudes outward and surrounds the side surface. The flange portion 64 is located a predetermined distance forward from the rear end of the cover portion 56a. Furthermore, a cover support portion 95 that supports the cover portion 56a is provided on the central partition wall portion 32c. The cover support portions 95 rotatably support the cover portion 56a, for example, by sandwiching the flange portion 64 from the front and rear at a predetermined interval.

[0195] Specifically, the cover support portion 95 has a flange receiving portion 96 and a flange retaining portion 97. The flange receiving portion 96 is a circular member through which the front cylindrical portion of the cover portion 56a passes and is fixed to the central partition portion 32c. An annular groove into which the flange portion 64 fits is formed on the rear side of the flange receiving portion 96. The flange retaining portion 97 is a circular member through which the rear cylindrical portion of the cover portion 56a passes and is attached from the rear side of the flange receiving portion 96 to function as a lid that retains the flange portion 64. The space in which the flange portion 64 is accommodated is configured to be larger than the flange portion 64. This allows the cover portion 56a to freely rotate around the central axis C1. The configuration of the cover portion 56a is not limited to this, and any configuration that rotatably supports a cylindrical member can be applied.

[0196] In the above embodiments, an annular combustor liner (see FIGS. 3 and 4, etc.) and a box-shaped combustor liner (see FIGS. 5 to 11, etc.) have been described. The shape of the combustor liner is not limited. For example, the combustor liner may be fan-shaped. A fan-shaped combustor liner has a structure obtained by cutting out a portion of an annular combustor liner without changing the shape of the combustion chamber, for example. By configuring a fan-shaped combustor liner in this way, it becomes possible to reproduce the characteristics of, for example, an annular combustor liner with high accuracy.

[0197] Furthermore, the number and arrangement of fuel injectors provided in the hydrogen combustor are not limited. For example, in Figures 3 and 4, an annular-type hydrogen combustor is configured in which the fuel injectors are arranged in a ring shape. Alternatively, a can-type hydrogen combustor may be configured in which multiple fuel injectors are arranged in cylindrical combustion cans and the fuel injectors are individually arranged. Furthermore, a cannular-type hydrogen combustor may be configured in which combustion cans including fuel injectors are arranged in a ring shape.

[0198] The above description has been given of an example in which a hydrogen combustor is mounted on an aircraft gas turbine engine. However, the present invention is not limited to this, and may also be applied to an aircraft power generation system, for example, in an aircraft whose propulsion system is fuel cell-powered or electrically powered. The power generation system includes a compressor that compresses air, a hydrogen combustor, and a turbine that uses combustion gas from the hydrogen combustor as a driving source to drive the compressor and generator. This is a system that generates electricity by driving a generator using the rotating shaft of the aircraft gas turbine engine described with reference to FIG. 1, for example.

[0199] The present invention may also be applied to stationary power generation systems. For example, the fuel injector and hydrogen combustor according to the present invention are used as gas turbine combustors in power generation systems (power plants) installed in factories or homes. Since the present invention can reduce the flame size, it is possible to realize, for example, a hydrogen combustor with a compact axial dimension. Such a hydrogen combustor is mounted on a small gas turbine engine used in a power plant of 1 MW or less. This makes it possible to realize a small power plant that is capable of stable operation with low NOx emissions.

[0200] In the above embodiment, the case where the fuel for the combustor is hydrogen has been described. However, the present invention can be applied to combustors that use fuels other than hydrogen gas, such as ammonia or gasified organic fuel. As the organic fuel, for example, a synthetic fuel (so-called carbon-neutral fuel) obtained by synthesizing carbon dioxide and hydrogen can be used. Furthermore, for example, the present invention can be applied to a hydrogen-mixed combustion type combustor that mixes and burns hydrogen gas and organic fuel.

[0201] It is also possible to combine at least two of the features of the present invention described above. That is, the various features described in each embodiment may be combined in any way without distinguishing between the embodiments. Furthermore, the various effects described above are merely examples and are not intended to be limiting, and other effects may also be achieved.

[0202] DESCRIPTION OF SYMBOLS 10...Aircraft gas turbine engine 13...Control unit 15, 15a, 15b...Hydrogen combustor 30, 30a, 30b...Combustor liner 40, 40a to 40k...Fuel injector 41...Air supply pipe 42, 42a...Swirl mechanism 43, 43a...Fuel supply pipe 44, 44a...Guide flow path section 46...Mixed gas injection section 51...First injection port 54...Fuel injection section 55...Fuel injection hole 56, 56a...Cover section 58...Second injection port 70...Screw fastening mechanism 90...Air intake section 100...Hydrogen combustor system

Claims

1. A fuel injector that injects a mixture of air and fuel into a combustor liner, comprising: an air supply pipe having a first injection port that communicates with the combustor liner; a swirler that is provided in a flow path of the air supply pipe and swirls the air; a fuel supply pipe having a fuel injection unit that injects the fuel into a flow path within the air supply pipe from the swirler to the first injection port; and a guide flow path unit that surrounds the first injection port and has a second injection port that injects an air flow that guides the mixture injected from the first injection port.

2. A fuel injector according to claim 1, wherein the fuel injection section is configured to inject the fuel at an injection pressure lower than the pressure of the fuel in the fuel supply pipe.

3. A fuel injector according to claim 1, wherein the fuel injection portion is a plurality of through holes provided in the fuel supply pipe, and the diameter of the through holes is 0.1 mm or more and 0.5 mm or less.

4. A fuel injector according to claim 1, wherein the fuel supply pipe is arranged inside the air supply pipe, and the fuel injection unit injects the fuel into the air supply pipe from inside the air supply pipe.

5. A fuel injector according to claim 4, wherein the fuel injection portion is a plurality of through holes provided at equal intervals around the central axis of the fuel supply pipe.

6. A fuel injector according to claim 1, wherein the fuel supply pipe is arranged outside the air supply pipe, and the fuel injection unit injects the fuel into the air supply pipe from outside the air supply pipe.

7. A fuel injector according to claim 1, wherein the fuel injector is configured so that the fuel injected from the fuel injection portion into the air supply pipe collides with an inner wall of the air supply pipe.

8. A fuel injector as set forth in claim 1, wherein the air supply pipe, the swirler, and the fuel supply pipe are modularized as an integrated unit to form a mixed gas injection section that injects the mixed gas, and the guide flow path section has a cover section that surrounds the outer periphery of the mixed gas injection section so that an air flow path is formed along the outer periphery of the mixed gas injection section, and the second injection port is formed between the outer periphery and the cover section.

9. A fuel injector as set forth in claim 8, wherein the combustor liner has a partition wall portion surrounding a combustion chamber and is fixed to a base portion, the cover portion and the mixed gas injection portion are configured to be detachable from each other, the cover portion is fixed to the partition wall portion, and the mixed gas injection portion is fixed to the base portion while being inserted into the cover portion.

10. A fuel injector according to claim 8, further comprising a screw mechanism provided on the opposite side of the fuel supply pipe from the fuel injection portion, for fixing the fuel supply pipe to the base portion.

11. A fuel injector according to claim 8, wherein the diameter of said cover portion is between 1 / 3 and 2 / 3 of the height of said combustor liner.

12. A fuel injector as set forth in claim 1, further comprising an air intake section that passes through the air supply pipe and flows into the guide flow path section and into the air supply pipe downstream of the swirler, the fuel supply pipe being arranged inside the air supply pipe, and the fuel injection section having a plurality of first fuel injection holes that are provided in the fuel supply pipe and inject the fuel into the air supply pipe, and a plurality of second fuel injection holes that are provided in the fuel supply pipe and inject the fuel into the combustor liner.

13. A fuel injector as set forth in claim 12, wherein the air intake section is at least one of a slit penetrating the outer periphery of the air supply pipe, or another swirler penetrating the outer periphery of the air supply pipe and causing a swirl of the air flowing from the guide flow path section to the air supply pipe.

14. A fuel injector according to claim 13, wherein the other swirler is a radial swirler that swirls the air in a flow path along the radial direction of the air supply pipe.

15. A fuel injector according to claim 12, wherein the diameter of the plurality of first fuel injection holes and the plurality of second fuel injection holes is 0.1 mm or more and 0.5 mm or less.

16. A fuel injector as set forth in claim 12, wherein the plurality of first fuel injection holes are through holes provided on a side surface of the fuel supply pipe at an angle to a central axis of the fuel supply pipe and are arranged at equal intervals around the central axis, and the plurality of second fuel injection holes are through holes provided on an end of the fuel supply pipe facing the combustor liner and are arranged at equal intervals around the central axis.

17. A fuel injector according to any one of claims 1 to 16, wherein the combustor liner has a partition wall portion surrounding the combustion chamber, and one or more dilution holes provided in the partition wall portion for introducing dilution air to interfere with the combustion gas, the dilution air diluting the combustion gas produced by combustion of the mixed gas.

18. A fuel injector according to any one of claims 1 to 16, wherein the combustor liner is annular, box-shaped, or sector-shaped.

19. A fuel injector according to any one of claims 1 to 16, wherein the swirler is either an axial swirler that swirls the air in a flow path along the axial direction of the air supply pipe, or a radial swirler that swirls the air in a flow path along the radial direction of the air supply pipe.

20. A fuel injector according to any one of claims 1 to 16, wherein the fuel is hydrogen.

21. A combustor comprising: a combustor liner; and a fuel injector that injects a mixed gas of air and fuel into the combustor liner, the fuel injector having: an air supply pipe having a first injection port communicating with the combustor liner; a swirler that is provided in a flow path of the air supply pipe and swirls the air; a fuel supply pipe having a fuel injection unit that injects the fuel into a flow path within the air supply pipe from the swirler to the first injection port; and a guide flow path unit that surrounds the first injection port and has a second injection port that injects an air flow to guide the mixed gas injected from the first injection port.

22. A gas turbine comprising: a combustor having a combustor liner and a fuel injector that injects a mixed gas of air and fuel into the combustor liner; and a turbine driven by combustion gas from the combustor, wherein the fuel injector has: an air supply pipe having a first injection port communicating with the combustor liner; a swirler that is provided on a flow path of the air supply pipe and swirls the air; a fuel supply pipe having a fuel injection unit that injects the fuel on a flow path within the air supply pipe from the swirler to the first injection port; and a guide flow path unit that surrounds the first injection port and has a second injection port that injects an air flow to guide the mixed gas injected from the first injection port.

23. A combustor system comprising: a combustor having a combustor liner and a fuel injector that injects a mixed gas of air and fuel into the combustor liner; a fuel supply line that supplies fuel to the fuel injector; and a control unit that controls the supply of the fuel to the fuel injector through the fuel supply line, wherein the fuel injector comprises: an air supply pipe having a first injection port that communicates with the combustor liner; a swirler that is provided in a flow path of the air supply pipe and swirls the air; a fuel supply pipe having a fuel injection unit that injects the fuel into a flow path within the air supply pipe from the swirler to the first injection port; and a guide flow path unit that surrounds the first injection port and has a second injection port that injects an air flow that guides the mixed gas injected from the first injection port.

24. A combustor system according to claim 23, wherein the control unit controls the supply of fuel to the fuel injector through the fuel supply line so that the fuel can be injected from the fuel injection unit in a choked state.

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