JP2001280641A - Gas turbine combustor, and method for mixing fuel and air in gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce NOx for achieving combustion even in a thin fuel concentration by improving the mixture of fuel and air in a gas turbine combustor. SOLUTION: In a swirl channel (15), a swirler (14) is arranged in a swirl pipe (15a), and a main nozzle (12) that is supported by the swirler is arranged at a center. The main nozzle is formed in a double pipe consisting of an outer pipe (12a) and an inner pipe (12b), and fuel is jetted into air that is supplied from the area between the outer and inner pipes via the inner pipe. A fuel/air mixture that is formed by mixing both of them is jetted out of a jetting hole (12hm). Therefore, the fuel is mixed with air in advance, which is further mixed with air, thus discharging the gas that has been mixed in advance and has a more uniform fuel concentration from the swirl channel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas turbine combustor and a method for mixing fuel and air in the gas turbine combustor.

[0002]

2. Description of the Related Art Gas turbines are widely used for power generation and various other purposes. This gas turbine injects fuel into air compressed to a high temperature by a compressor and burns in a combustion cylinder to generate combustion gas, which is used to rotate a turbine (rotor blade) to obtain power. is there. In order to increase the efficiency of the gas turbine, the temperature of the combustion gas at the turbine inlet is preferably as high as possible. Conventionally, it has been designed to increase the temperature of the combustion gas.

However, in these gas turbines, nitrogen oxides (NOx) have been developed due to recent tightening of exhaust gas regulations.
Is expected to be reduced. This NOx is generated when the combustion gas reaches a certain temperature. Therefore, in order to reduce NOx, it is necessary to keep the maximum temperature of the combustion gas below the temperature at which NOx is generated.

Here, it can be considered that the temperature of the combustion gas is basically determined by the amount of air with respect to the fuel at the time of combustion, that is, the amount of combustion air. The higher the amount of air, the higher. Therefore,
In order to reduce NOx, it is necessary to increase the amount of combustion air and perform combustion with a low fuel concentration.

[0005]

However, there is a problem that if the combustion is performed with such a low fuel concentration in the conventional combustor, unstable combustion occurs, and the fuel concentration cannot be sufficiently reduced to reduce NOx. Did not. SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a gas turbine combustor that can improve the mixing of fuel and air and can burn even a low fuel concentration and reduce NOx.

[0006]

SUMMARY OF THE INVENTION According to the present invention, air and fuel pipes compressed by a compressor are used to generate a pilot flame and a premix ignited by the pilot flame. A gas turbine combustor which mixes with fuel to be ejected is provided which has a mixing promoting means for promoting mixing of fuel and air in a fuel pipe or after the fuel is ejected. In the gas turbine combustor configured as described above, the mixing of fuel and air is promoted in the fuel pipe or after the fuel is injected by the mixing promoting means, and combustion can be performed even at a low fuel concentration.

[0007] The mixing promoting means may be an air mixing means in the fuel pipe for mixing air and fuel in the fuel pipe. In this case, the air mixing means in the fuel pipe may include an air passage disposed outside the double pipe. It is constituted by ejecting fuel from the fuel passage arranged inside the double pipe to the air supplied therethrough.Preferably, the tip of the fuel passage is reduced in diameter, or the fuel passage is formed at a central portion in the cross section of the fuel passage. It is configured by ejecting air from an air passage, and is also configured by providing a swirler in a fuel pipe.

[0008] The mixing promoting means may be a fuel adhesion preventing means for preventing the injected fuel from adhering to the surface of the fuel pipe. In this case, the fuel adhesion preventing means moves the injection hole along the injection direction. It is constructed by expanding the diameter in a tapered shape, or by blowing air from the downstream side of the injection hole of the fuel pipe.

When the fuel pipe is disposed at the center of the swirl passage through which the air swirled by the swirler passes, the mixing promoting means is disposed upstream of the injection hole and agitates the air in the injection hole region. In this case, the injection hole area stirring means is constituted by a column extending radially from the fuel pipe to the outer peripheral wall of the swirl flow path or halfway to the outer peripheral wall. . Then, the cylinder is extended radially from the fuel pipe halfway to the outer peripheral wall of the swirl flow path,
A swirler may be provided on the outer peripheral side. Alternatively, the injection hole area stirring means may be a turbulence forming means formed on the surface of the fuel pipe near the upstream of the injection hole, or may be a thick wedge member provided downstream at the junction between the swirler and the fuel pipe.

In the case where the swirler is provided in the air flow path from which the fuel is jetted, the mixing promoting means can be configured by providing the fuel injection hole at a radially central portion of the swirler.
When the swirler is an airfoil swirler having an airfoil cross section,
The fuel injection hole may be provided on the ventral side of the airfoil swirler, or may be provided on the trailing edge of the airfoil swirler.

The mixing promoting means is provided with fuel injection holes in the central portion and the outer peripheral wall of the air flow path, so that the injected fuel does not collide with each other and cancel the momentum. In this case, it is preferable that the injection holes in the central portion and the outer peripheral wall are offset in the axial direction, or that the injection holes in the central portion and the outer peripheral wall are shifted in injection angle.

[0012] The mixing promoting means may be constituted by means for blowing air from the outer peripheral wall of the air flow path and means for blowing fuel from the outer peripheral wall downstream therefrom. Further, the mixing promoting means may be constituted by an air flow path provided with a throttle and a fuel injection hole opened in the throttle section. According to the present invention, a fuel in a gas turbine combustor comprising the steps of mixing a fuel and air in a fuel pipe to obtain a fuel-air mixture, and injecting the fuel-air mixture into air And a method of mixing air.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a basic structure around a combustor of a conventional gas turbine to which the present invention is applied will be described with reference to FIG. A combustor 3 is disposed in a cabin 2 formed by a casing 1,
In addition, high-temperature air compressed by a compressor 4 (only part of which is shown) is introduced into the passenger compartment 2 as shown by an arrow 100. The combustor 3 includes a combustion tube 6 that burns fuel and air to generate combustion gas, and an introduction unit 5 that guides the fuel and air to the combustion tube 6 to the combustion tube 6. A stator blade 8 is connected to the stationary blade 8 via a seal 7, and a moving blade 9 is disposed downstream of the stationary blade 8.

The introduction section 5 has one pilot nozzle 11 and a plurality of main nozzles 12 inside the combustion air guide cylinder 10.
Are arranged. The high-temperature compressed air introduced into the passenger compartment 2 from the compressor 4 passes around the combustion air guide cylinder 10 and goes upstream as indicated by an arrow 101,
As shown by an arrow 102, the fuel is introduced into the combustion air guide cylinder 10 from a combustion air inlet 13 formed at the upstream end of the combustion air guide cylinder 10. The air introduced into the combustion air guide cylinder 10 is converted into swirl air in a swirl flow path 15 having a plurality of swirlers 14, and then the fuel injected from the main nozzle 12 is mixed to form a premixed air. And sent to the combustion cylinder 6.

The air introduced into the combustion air guide cylinder 10 is supplied to the air passage 1 around the pilot nozzle 11.
1a, the fuel is diffused and combusted with the fuel injected from the pilot nozzle 11 downstream of the pilot nozzle 11 to generate a pilot flame. The pilot flame ignites the premixed gas discharged from the swirl flow path 15, thereby generating combustion gas. The tip 16 of the pilot nozzle 11 is disposed in a pilot cone 17 that spreads in a megaphone shape.

Hereinafter, embodiments of the gas turbine combustor of the present invention applied to the above-described conventional gas turbine will be described. First, a first embodiment will be described. In the first embodiment, fuel and air are mixed in a fuel pipe. FIG. 1 is a view for explaining the features of the first embodiment, which shows the inside of a swirl channel 15 forming a premixer, and the swirl channel 15 is provided inside a swirl tube 15a. The main nozzle 1 supported at the center by the swirler 14
2 are provided.

As a feature of the present invention, the main nozzle 12 is a double pipe composed of an outer pipe 12a and an inner pipe 12b, and the inner nozzle 12b is contained in air supplied from between the outer pipe 12a and the inner pipe 12b. The fuel is ejected through the nozzle and the two are mixed to form a fuel-air mixture, which is injected from the injection hole 12hm.

Therefore, conventionally, the fuel is mixed with the air only after leaving the injection hole, but in the first embodiment, the fuel is mixed with the air before exiting the injection hole 12 hm, and further mixed with the air. Are mixed, the premixed gas having a more uniform fuel concentration can be discharged from the swirl flow path 15.

FIG. 2 shows a first modification of the first embodiment, in which the tip of the inner tube 12b of the main nozzle 12 is reduced in diameter to reduce the force of the fuel supplied into the air. And a better mix of fuel and air. FIG. 3 shows a second modification of the first embodiment, in which a nozzle swirler 12m is formed in a mixing area downstream of the double pipe of the main nozzle 12 to improve the mixing of fuel and air. Things.

FIG. 4 shows a third modification of the first embodiment. In contrast to the first embodiment, air is blown into the fuel and the air is injected into the main nozzle 12. Both are mixed. In the figure, the air injection pipe 12c is attached so as to pierce from the side, but air may be ejected from the inner pipe as a double pipe as in the first embodiment. Further, if a plurality of air ejection holes are provided, mixing is further promoted. This third modified example can also obtain the same effect as that of the first embodiment.

Although the first embodiment and each of the modifications described above have been described taking the main nozzle 12 as an example, the present invention can also be applied to the pilot nozzle 11. Further, the ratio of air and fuel mixed in the double pipe must be outside the flammability limit in order to prevent ignition in the double pipe.

Next, a second embodiment will be described.
In the second embodiment, only the fuel is ejected from a centrally arranged nozzle as in the related art, but the fuel ejected from the nozzle is prevented from adhering to the surface of the nozzle in the form of a film. FIG. 5 shows the characteristics of the swirl passage 1hf.
The opening on the fifth side is a cone-shaped enlarged opening 12g. This prevents the ejected fuel from adhering to the surface of the main nozzle 12 in the form of a film on the downstream side, thereby improving the uniformity of the premixed gas.

Next, a first modification of the second embodiment will be described. This is because, as in the first embodiment, the nozzle is formed as a double tube, but mixing is not performed inside, and the injected fuel is provided by providing an air injection hole downstream of the fuel injection hole, so that the injected fuel can be supplied to the nozzle. It prevents adhesion to the surface. FIG. 6 shows the structure of the main nozzle 1
Reference numeral 2 denotes a double pipe composed of an outer pipe 12a and an inner pipe 12b, and the fuel passes through a space between the outer pipe 12a and the inner pipe 12b and is ejected from a fuel injection hole 12hf. On the other hand, the air is
Is ejected from the air injection holes 12ha downstream of the fuel injection holes 12hf. Therefore, the fuel injection holes 12
The fuel ejected from hf is prevented from adhering to the surface of the main nozzle 12.

Next, a third embodiment will be described.
This is because the turbulence generating means is provided on the outer surface of the nozzle upstream of the fuel injection hole, and the fuel is diffused by injecting the fuel from the fuel injection hole into the air agitated by the turbulence generation means. Is prevented from adhering to the surface of the nozzle. FIGS. 7A and 7B are views for explaining the structure of the third embodiment, and FIG.
As shown in FIG. 2, a cylinder 14 'extending to the swirl pipe 15a is provided upstream of the fuel injection hole 12 of the main nozzle 12. As shown in FIG. 7B, the air that has passed through the cylinder 14 'generates a vortex called a horseshoe vortex near the surface of the main nozzle 12, and the turbulence of the air increases in this region. Therefore, by injecting fuel from the injection holes 12hf into this area, the fuel is diffused, and the main nozzle 1h
2 is prevented from adhering to the surface. The cylinder 14 ′ may be halfway as shown by the broken line, or the cylinder 14 ′
If the air can be sufficiently agitated, the swirler 14 may be omitted.

FIG. 8 shows a first modification of the third embodiment.
4 '. FIG. 9 shows a second modification of the third embodiment, in which a plurality of turbulence generating surfaces are provided on the surface of the main nozzle 12 upstream of the injection hole 12hf instead of the column 14 'of the third embodiment. Are provided.

FIG. 10 shows a third modification of the third embodiment. In place of the column 14 'of the fourth embodiment, the swirler 14 is replaced with an annular wedge having a wedge-shaped cross section whose thickness increases on the downstream side. It is attached to the main nozzle 12 via a member 12w, and the annular wedge member 12w disturbs the air on the surface of the main nozzle 12. The rear end of the annular wedge member 12w is warped outward. The fourth embodiment described above,
In addition, although the modified example is described using the main nozzle 12 as an example, the modified example can be applied to the pilot nozzle 11.

Next, a fourth embodiment will be described. This is to improve the mixing of fuel and air by providing a fuel injection hole in the swirler and jetting the fuel to the center of the swirl flow path 15. (A) and (B) of FIG.
This is a view for explaining the structure of the fourth embodiment, in which a fuel injection hole 14hf is provided at an intermediate portion between the main nozzle 12 and the swirl pipe 15a as shown in FIG. As shown in FIG. 11A, the swirler 14 having an airfoil cross-section is opened on the ventral side of the swirler 14, and is disposed behind the throat portion where the flow path is narrowed by the adjacent swirler 14. It prevents the surface from flowing in the form of a film.

FIG. 12 is a view for explaining the structure of a modification of the fourth embodiment. A fuel injection hole 14hf is formed at the rear end of the swirler 14. The fifth embodiment and its modification are configured as described above, and the fuel is ejected from the swirler 14 to the center of the swirl channel 15,
Separates from the inner and outer wall surfaces and mixes well with air.

Next, a fifth embodiment will be described.
In the fifth embodiment, the fuel is injected from the center and the outer periphery of the air flow path. FIGS. 13A and 13B are views for explaining the structure of the fifth embodiment, in which a swirl pipe 15 a is provided in addition to a fuel injection hole 12 hf provided in the main nozzle 12. It has a fuel injection hole 15hf.

The fuel injection holes 12hf and the fuel injection holes 15
hf is offset in the axial direction as shown in FIG. 13A, the injection directions are not overlapped as shown in FIG. 13B, and the injected fuel Are prevented from colliding with each other and weakening the diffusion.
The fifth embodiment is configured as described above, and the fuel is dispersed and injected. Therefore, the mixing with the air is improved, and the operation can be performed even at a low fuel concentration.

Next, a sixth embodiment will be described. In the sixth embodiment, fuel and air are ejected from the outer peripheral portion of the air flow path. FIGS. 14A and 14B are views for explaining the structure of the sixth embodiment, in which a swirl tube covering tube 15b is disposed outside a swirl tube 15a and is located downstream. Is a swirl tube 15
Air is introduced from an upstream side into an air passage 15c between the swirl pipe 15a and the swirl pipe covering pipe 15b, which is connected to the swirl pipe 15a. The air is supplied from an air injection hole 15ha provided in the swirl pipe 15a. It is injected into the swirl channel 15. Further, the fuel is injected into the swirl channel 15 from a fuel injection hole 15hf that crosses the air passage 15c and opens on the inner surface of the swirl channel 15. Here, the fuel injection hole 15hf
Is disposed upstream of the air injection hole 15ha, and the fuel injected from the fuel injection hole 15hf
Is diffused by the air injected from the air. The sixth embodiment is configured as described above, and the fuel is dispersed and injected. Therefore, the mixing with the air is improved, and the operation can be performed even at a low fuel concentration.

Next, a seventh embodiment will be described. In the seventh embodiment, the swirl tube is reduced in diameter immediately after the swirler. FIG. 15 is a view showing the structure of the seventh embodiment. The swirl pipe 15a is reduced in diameter at the swirler 14 so as to have the smallest diameter, and is expanded downstream. The fuel injection hole 12hf is provided at a place where the diameter of the swirl pipe 15a is smallest. The seventh embodiment is configured as described above,
At the enlarged portion, the air is greatly disturbed together with the fuel to improve the mixing.

The swirler 14 can be removed if the diameter expansion ratio can be increased and the fuel and air can be sufficiently mixed only by the diameter expansion. Further, in the seventh embodiment, there is a possibility that self-ignition may occur by performing combustion close to diffusion combustion. In such a case, it is not necessary to produce a flame with the pilot nozzle 11, so that the pilot nozzle 11 can be removed.

Although the first to seventh embodiments have been described above, the structures of the respective embodiments can be appropriately combined to obtain a better mixture of fuel and air. it can. Thus, as an example, a combination of the sixth embodiment and the seventh embodiment is referred to as an eighth embodiment.
15 is shown in FIG. Although the first to sixth embodiments have been described on the premise that the main nozzle 12 is used, the first to sixth embodiments can also be applied to the pilot nozzle 11.

[0035]

According to the gas turbine combustor described in the claims, air and fuel compressed by a compressor are used to generate a pilot flame and a premixture ignited by the pilot flame. Using a mixing device for mixing the fuel ejected from the pipe, but having a mixing promoting means for promoting mixing of fuel and air in the fuel pipe or after the fuel is ejected,
Mixing promotion means promotes mixing of fuel and air in the fuel pipe or after the fuel is ejected, so that combustion can be performed even at a low fuel concentration and NOx can be reduced. In addition, it is possible to prevent the formation of a locally high fuel concentration portion, which also contributes to the reduction of NOx. Also, it is possible to prevent the combustion from becoming unstable and having a high heat generation rate, which also contributes to the reduction of NOx. . In particular, if the mixing promoting means is a fuel pipe air mixing means for mixing air and fuel in the fuel pipe, the air and fuel can be mixed in the fuel pipe, and the mixing is promoted compactly. And the mixed fuel and air are then further mixed with air and double mixed, resulting in very good mixing.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating features of a first embodiment.

FIG. 2 is a diagram illustrating characteristics of a first modification of the first embodiment.

FIG. 3 is a diagram illustrating features of a second modification of the first embodiment.

FIG. 4 is a diagram illustrating characteristics of a third modification of the first embodiment.

FIG. 5 is a diagram illustrating features of the second embodiment.

FIG. 6 is a diagram illustrating characteristics of a modification of the second embodiment.

FIGS. 7A and 7B are views for explaining features of the third embodiment, in which FIG. 7A is a cross-sectional view taken along a section passing through an axis, and FIG.
FIG. 4 is a perspective view illustrating the flow of air around a cylinder.

FIG. 8 is a diagram illustrating features of a first modification of the third embodiment.

FIG. 9 is a diagram illustrating features of a second modification of the third embodiment.

FIG. 10 is a diagram illustrating characteristics of a third modification of the third embodiment.

FIG. 11 is a diagram illustrating features of the fourth embodiment.

FIG. 12 is a diagram illustrating features of a modification of the fourth embodiment.

FIG. 13 is a diagram illustrating features of the fifth embodiment.

FIG. 14 is a diagram illustrating features of the sixth embodiment.

FIG. 15 is a diagram illustrating features of the seventh embodiment.

FIG. 16 is a diagram illustrating features of the eighth embodiment.

FIG. 17 is a diagram showing a basic structure around a combustor of a conventional gas turbine to which the present invention can be applied.

[Explanation of symbols]

 3 ... Combustor 6 ... Combustion cylinder 10 ... Combustion air guide cylinder 11 ... Pilot nozzle 12 ... Main nozzle 12a ... Outer pipe 12b ... Inner pipe 12c ... Air injection pipe 12ha ... Air ejection hole 12hf ... Fuel injection hole 12hm ... Fuel and air 12t ... Protrusion 12w ... Wedge member 14 ... Swirler 14 '... Cylinder 14hf ... Fuel injection hole 15 ... Swirl channel 15a ... Swirl tube 15ha ... Air injection hole 15hf ... Fuel injection hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Yoshitani 2-1-1 Shinama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. No. 1 Inside Mitsubishi Heavy Industries, Ltd. Takasago Research Institute (72) Inventor Tatsuo Ishiguro 2-1-1, Araimachi Shinhama, Takasago City, Hyogo Prefecture Inside Mitsubishi Heavy Industries, Ltd. 1-1 1-1, Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Koji Watanabe 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Mitsui Heavy Industries, Ltd. No. 1-1, Takasago Works, Mitsubishi Heavy Industries, Ltd. (72) Inventor Takehiko Shimizu Arai, Takasago City, Hyogo Prefecture Niihama 2 chome No. 1 Mitsubishi Heavy Industries, Ltd. Takasago Works (72) inventor Mitsuru Inada Hyogo Prefecture Takasago Araichoshinhama 2 chome No. 1 Mitsubishi Heavy Industries, Ltd. Takasago Research Institute

Claims (23)

[Claims] 1. A gas turbine for mixing air compressed by a compressor and fuel injected from a fuel pipe to generate a pilot flame and a premixed gas ignited by the pilot flame. A gas turbine combustor, comprising: a combustor having mixing promoting means for promoting mixing of fuel and air in a fuel pipe or after fuel is injected. 2. The gas turbine combustor according to claim 1, wherein the mixing promoting means is a fuel pipe air mixing means for mixing air and fuel in the fuel pipe. 3. The air mixing means in the fuel pipe is formed by ejecting fuel from a fuel passage provided inside the double pipe to air supplied through an air passage provided outside the double pipe. The gas turbine combustor according to claim 2, wherein: 4. The gas turbine combustor according to claim 3, wherein the front end of the fuel passage has a reduced diameter. 5. The gas turbine combustor according to claim 3, wherein the air mixing means in the fuel pipe is configured to eject air from an air passage to a central portion in a cross section of the fuel passage. 6. The gas turbine combustor according to claim 2, further comprising a fuel pipe swirler. 7. The gas turbine combustor according to claim 1, wherein the mixing promoting means is a fuel adhesion preventing means for preventing the injected fuel from adhering to the surface of the fuel pipe. 8. The gas turbine combustor according to claim 7, wherein the fuel adhesion preventing means is formed by expanding the diameter of the injection hole in a tapered shape along the injection direction. 9. The gas turbine combustor according to claim 7, wherein the fuel adhesion preventing means blows air from a downstream side of the injection hole of the fuel pipe. 10. A fuel pipe is disposed at the center of a swirl flow path through which air swirled by a swirler passes, and the mixing promoting means is disposed upstream of the injection hole and agitates the air in the injection hole region. 2. The gas turbine combustor according to claim 1, wherein the gas turbine combustor is an injection hole area stirring means. 11. The injection hole region stirring means is a cylinder extending radially from the fuel pipe to the outer peripheral wall of the swirl flow path or halfway to the outer peripheral wall.
A gas turbine combustor according to claim 1. 12. The gas turbine according to claim 11, wherein the column extends radially from the fuel pipe to a position halfway to an outer peripheral wall of the swirl flow path, and a swirler is provided on the outer peripheral side. Combustor. 13. The gas turbine combustor according to claim 10, wherein the injection hole region stirring means is a turbulence forming means formed on the surface of the fuel pipe near the upstream of the injection hole. 14. The gas turbine combustor according to claim 10, wherein the injection hole area stirring means is a downstream thick wedge member provided at a junction between the swirler of the injection hole and the fuel pipe. 15. A swirler is provided in an air flow path from which fuel is ejected, and the mixing promoting means is provided with a fuel injection hole at a radially central portion of the swirler. A gas turbine combustor as described. 16. The gas turbine combustor according to claim 15, wherein the swirler is an airfoil swirler having an airfoil cross section, and wherein the fuel injection hole is provided on a ventral side of the airfoil swirler. . 17. The gas turbine combustion according to claim 15, wherein the swirler is an airfoil swirler having an airfoil cross section, and the fuel injection hole is provided at a trailing edge of the airfoil swirler. vessel. 18. The mixing promoting means includes a fuel injection hole provided in a central portion and an outer peripheral wall of an air flow path, and prevents the injected fuel from colliding with each other and canceling out the momentum. 2. The injection hole of claim 1 is formed.
A gas turbine combustor according to claim 1. 19. The gas turbine combustor according to claim 18, wherein the injection holes in the central portion and the outer peripheral wall are offset in the axial direction. 20. The gas turbine combustor according to claim 18, wherein the injection holes of the central portion and the outer peripheral wall are shifted in injection angle. 21. The mixing means according to claim 1, further comprising means for blowing air from the outer peripheral wall of the air flow path, and means for blowing fuel from the outer peripheral wall downstream therefrom.
A gas turbine combustor according to claim 1. 22. The gas turbine combustor according to claim 1, wherein the mixing promoting means comprises an air flow path provided with a throttle, and a fuel injection hole opened in the throttle. 23. A method for producing a fuel-air mixture by mixing fuel and air in a fuel pipe, and injecting the fuel-air mixture into the air, wherein the fuel and the fuel are mixed in a gas turbine combustor. Air mixing method.