Gas turbine combustor

Abstract

The objective is to provide a gas turbine combustor that can improve ignition performance during startup without complicating the structure. [Solution] A combustor for a hydrogen gas turbine, comprising an annular housing that forms a combustion field, a fuel injection nozzle that injects a mixture of fuel and air toward the combustion field, and an igniter arranged on the outer circumference of the housing, wherein the axis of the fuel injection nozzle is inclined with respect to the axis of the housing.

Description

Technical Field

[0001] The present disclosure relates to a gas turbine combustor.

Background Art

[0002] Patent Document 1 discloses that by providing an injection hole for auxiliary fuel near the igniter of a hydrogen gas turbine, the ignition performance can be improved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional gas turbine combustor, since an injection hole dedicated for ignition and an auxiliary fuel introduction passage are provided, the structure becomes complicated. Such complication is not suitable for, for example, a small gas turbine.

[0005] Therefore, an object of the present disclosure is to provide a gas turbine combustor that can improve the ignition performance at startup without complicating the structure.

Means for Solving the Problems

[0006] The present application discloses a combustor of a gas turbine, which has an annular housing that forms a combustion field, a fuel injection nozzle that injects a mixture of fuel and air toward the combustion field, and an igniter disposed on the outer periphery of the housing, and the axis of the fuel injection nozzle is inclined with respect to the axis of the housing.

[0007] The fuel injection nozzle may have, inside thereof, a first air injection port and a second air injection port arranged in the injection direction, and a fuel injection port may be disposed between the first air injection port and the second air injection port.

[0008] The incline angle may be between 45° and 70°.

[0009] The gas turbine combustor may be 10kW to 90kW. [Effects of the Invention]

[0010] According to this disclosure, since the fuel injected from the fuel injection nozzle is ejected toward the igniter, ignition performance during startup can be improved without complicating the structure. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a perspective view illustrating the structure of the gas turbine combustor 10. [Figure 2] Figure 2 is a cross-sectional view illustrating the structure of the gas turbine combustor 10. [Figure 3] Figure 3 is a perspective view of the fuel injection nozzle 20. [Figure 4] Figure 4 is a cross-sectional view of the combustion injection nozzle 20. [Figure 5] Figure 5 illustrates a tilted flame. [Modes for carrying out the invention]

[0012] 1. Basic structure of a gas turbine combustor The gas turbine combustor of this disclosure can be advantageously used in gas turbine combustors that use fuels that are lighter in mass and have a higher combustion temperature than hydrogen or conventionally used hydrocarbon-based substances. Figure 1 is a perspective view illustrating the gas turbine combustor 10 (however, only some components are shown for illustrative purposes), Figure 2 is a diagram showing the area around one fuel injection nozzle 20 in the gas turbine combustor 10, Figure 3 is an external perspective view of the fuel injection nozzle 20, and Figure 4 is a diagram illustrating the internal structure of the fuel injection nozzle 20.

[0013] As can be seen from Figures 1 and 2, in the gas turbine combustor 10, the fuel injection nozzle 20 is installed in the opening 31a of the housing 31 of the combustion chamber 30 that defines the combustion field A. Compressed air PA flows into the fuel injection nozzle 20 from a compressor (not shown) connected to a turbine (not shown) via an annular compressed air supply ring 40 defined on the outer circumference of the combustion chamber 30. Fuel F also flows in from a fuel tank (not shown) via a fuel supply pipe 21, and the compressed air PA and fuel F are mixed and released into the combustion field A as indicated by arrow M for combustion.

[0014] As can be seen in Figure 1, multiple fuel injection nozzles 20 are arranged around the outer circumference of the housing 31 at predetermined intervals, and a mixture of fuel and air is discharged from each fuel injection nozzle 20 toward the combustion field A.

[0015] Furthermore, as shown in Figure 1, an igniter 50, which is an ignition device, is positioned on the outer periphery of the housing 31, and is configured to ignite the fuel-air mixture released into the combustion field A, thereby generating a flame.

[0016] Each fuel injection nozzle 20 has a substantially cylindrical peripheral wall portion 23 on which a flange 22, etc., is formed, as shown in Figures 3 and 4, and is fitted into the opening 31a of the housing 31 such that the end face with the nozzle opening 20a faces the combustion field A. A first air outlet 20b opens in the substantially central region of the nozzle opening 20a of the fuel injection nozzle 20, and a slit-shaped (or dot-shaped) second air outlet 20c is formed around it, and a plurality of fuel injection ports 20d are arranged generally evenly between the first air outlet 20b and the second air outlet 20c.

[0017] Incidentally, the first air ejection port 20b, the fuel injection port 20d, and the second air ejection port 20c may be arranged concentrically in order to inject compressed air and fuel more evenly. As can be seen from FIG. 4, the compressed air flow PA sent through the compressed air supply ring 40 flows into the air flow path from the air intake port 40a. A part of it is ejected from the first air ejection port 20b, and another part is ejected from the second air ejection port 20c. The fuel supplied through the fuel flow path 21a inside the fuel supply pipe 21 is ejected from the fuel injection port 20d between the first air ejection port 20b and the second air ejection port 20c in the manner described below. The injection amount of the fuel is adjusted so that the combustion temperature becomes the equivalence ratio at 1500°C or lower.

[0018] The diameter of the fuel injection port 20d is designed to be smaller than the flame extinction distance of the fuel in order to prevent flashback. Specifically, since the flame extinction distance of hydrogen is about 0.64 mm, when the fuel is hydrogen, the diameter of the fuel ejection port 20d can be, for example, 0.6 mm or less.

[0019] Also, in the present disclosure, as schematically shown in FIGS. 5(a) and 5(b), the fuel injection nozzle 20 is configured to generate a flame F that tilts at an angle θ in the circumferential direction with respect to the direction in which the axis O of the ring of the annular housing 31 extends. That is, the fuel injection nozzle 20 injects a mixture of fuel and air in the direction of the angle θ. Specific methods therefor are not particularly limited, and examples include tilting the orientation of the fuel injection nozzle 20 itself. Here, θ is the direction in which the concentration of the injected mixture is the highest. The specific value of the angle θ is not particularly limited, and examples include 45° to 70°.

[0020] 2. Effects, etc. Hydrogen has a higher combustion temperature and is more likely to generate NOx compared to hydrocarbon fuels that have been commonly used until now. Therefore, in a combustor used for a hydrogen gas turbine, in the mixture of fuel and air, it is required to make the fuel concentration as uniform as possible in the mixing process from the input of fuel and air to before combustion, so that a region where the fuel concentration becomes locally high and the combustion temperature becomes high does not occur. In particular, in the case of a small gas turbine, since the space from the air and fuel inlets to the combustion field becomes small, it is preferable that the fuel can be made uniform in the air as quickly as possible.

[0021] Therefore, in the gas turbine combustor 10 of this embodiment, by configuring the first air ejection hole 20b, the second air ejection hole 20c, and the fuel injection port 20d as described above, hydrogen and air concentrate in a narrow range in the combustion chamber A on the downstream side of the fuel injection nozzle 20, so that the uniformity of the fuel in the air can be enhanced. However, on the other hand, in such a configuration, since the high-temperature region concentrates in a narrow range of the combustion chamber on the downstream side of the fuel injection nozzle, it is difficult to supply the mixture of hydrogen and oxygen to the periphery of the igniter and it is difficult to ignite. Also, even if ignition occurs, a flame is formed only directly below the center of the fuel injection nozzle. In this case, the space other than the fuel injection nozzle becomes a wasted space where no flame is formed. If this wasted space can be effectively utilized, the gas turbine combustor can be downsized. On the contrary, as in the present disclosure, since the flame formed from the fuel injection nozzle 20 is inclined in the circumferential direction, the mixture of hydrogen and oxygen is injected toward the igniter 50 installed on the outer periphery of the housing 31, and since the mixture reaches the outer peripheral side, the ignitability by the igniter 50 can be enhanced without complicating the structure. Since the circumferential space can be utilized in this way, the gas turbine combustor can be downsized, and the effect is particularly remarkable in a small engine.

[0022] The configuration of this embodiment is particularly advantageous for a gas turbine that uses hydrogen as fuel, and among them, for a small gas turbine combustor in the range of, for example, 10 kW to 90 kW class, more preferably 10 kW to 60 kW class. [Explanation of Symbols]

[0023] 10...Gas turbine combustor, 20...Fuel injection nozzle, 21...Fuel supply pipe, 40...Compressed air supply pipe, 50...Igniter

Claims

1. It is a combustor for a hydrogen gas turbine, It comprises an annular housing that forms a combustion field, a fuel injection nozzle that injects a mixture of fuel and air toward the combustion field, and an igniter arranged on the outer circumference of the housing. The shaft of the fuel injection nozzle is positioned at an inclination with respect to the shaft of the housing. The combustor of a hydrogen gas turbine.

2. The combustor for a hydrogen gas turbine according to claim 1, wherein the fuel injection nozzle has a first air inlet and a second air inlet arranged in the injection direction inside it, and a fuel inlet is disposed between the first air inlet and the second air inlet.

3. The combustor for a hydrogen gas turbine according to claim 1 or 2, wherein the inclination angle of the inclination is 45° to 70°.

4. The combustor for the hydrogen gas turbine according to claim 1 or 2, wherein the combustor for the hydrogen gas turbine has a power of 10 kW to 90 kW.

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