JPH07217888A - Air circulating device for gas turbine combustion device - Google Patents

Abstract

PURPOSE:To provide an air circulating device for a gas turbine combustion device in which a combustion efficiency is improved by improving a mixing characteristic of fuel and air, an amount of generated smoke and NOx is reduced and at the same time a high thrust force can be attained. CONSTITUTION:An outer circumferential part of a fuel injection nozzle 13 of a combustion device 11 is provided with an air circulating device 15. An end part 17a at a downstream side of an inner sleeve 17 of the air circulating device 15 is positioned at an upstream side higher than an end part 16a at a downstream side of the outer sleeve 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine combustor air swirler suitable for mixing fuel and air in a gas turbine combustor such as a jet engine.

[0002]

2. Description of the Related Art A gas turbine engine is one of the jet engines used for aircraft.

Conventionally, such a gas turbine engine has the following structure, for example. Figure 7
As shown in FIG. 1, the gas turbine engine 1 includes a fan 2 that takes in air and a compressor 3 that compresses the taken-in air.
A combustor 4 that mixes fuel with the compressed air and burns it; and an output turbine 5 that drives the fan 2 and the compressor 3 by the combustion gas generated in the combustor 4.
And an exhaust pipe 6 for ejecting combustion gas to the rear. As shown in FIG. 8, the combustor 4 is
A cylindrical air swirler 9 having a large number of swirl vanes 8 is provided on the outer peripheral side of the fuel ejection nozzle 7. In such a combustor 4, compressed air is sent from the compressor 3 to the fuel jetted from the fuel jet nozzle 7 to mix them,
By igniting this, combustion gas is generated. At this time, the air sent to the combustor 4 is swirled around its axis by the air swirler 9, so that the flame combustion state is maintained at the downstream position and stable combustion is obtained.

[0004]

However, the air swirler of the conventional gas turbine combustor as described above has the following problems.
There are the following problems. In the combustor 4, the fuel ejected from the fuel ejection nozzle 7 and the air that is swirled around the axis of the combustor 4 by the air swirler 9 and fed into the combustor 4 respectively form a layer, which may not mix well. is there. As a result, there is a problem that the combustion efficiency becomes poor, it becomes difficult to reduce the amount of smoke and NOx generated in the combustion gas, and the desired thrust cannot be obtained. The present invention has been made in consideration of the above points, and improves the mixing efficiency of fuel and air to improve combustion efficiency, reduce the amount of smoke and NOx generated, and increase the thrust. An object is to provide an air swirler of a gas turbine combustor that can be obtained.

[0005]

The invention according to claim 1 is
In a combustor of a gas turbine, a cylindrical outer sleeve extending along an inflow direction of air into the combustor, an inner sleeve disposed inside the outer sleeve with a certain distance, and the outer side. An air swirler including a plurality of swirl vanes provided in the circumferential direction between the sleeve and the inner sleeve is provided on the outer peripheral side of the fuel injection nozzle, and the downstream end of the inner sleeve is the outer sleeve. It is characterized in that it is arranged on the upstream side with respect to the downstream end.

According to a second aspect of the present invention, in the air swirler for a gas turbine combustor according to the first aspect, the downstream edge of the swirl vane has a downstream edge and the inner side of the outer sleeve. It is characterized in that it is formed in a shape that linearly connects with the downstream end of the sleeve.

According to a third aspect of the present invention, in the air swirler for a gas turbine combustor according to the first aspect, the downstream edge of the swirl vane has a downstream end and the inner side of the outer sleeve. It is characterized in that it is curved on either the upstream side or the downstream side with respect to the straight line connecting the downstream end of the sleeve.

According to a fourth aspect of the present invention, in the air swirler for a gas turbine combustor according to the first aspect, the downstream edge of the swirl vane has a downstream end and the inner side of the outer sleeve. It is characterized in that it is formed in a shape having a step between the downstream end of the sleeve.

The invention according to claim 5 relates to claims 1 to 4.
In the air swirler for a gas turbine combustor according to any one of claims 1 to 5, at least downstream end portions of the outer sleeve and the inner sleeve are configured to have a diameter that gradually decreases along the axial direction of the combustor. It is characterized by that.

[0010]

According to the first aspect of the invention, the air flowing from the upstream side of the air swirler into the space between the outer sleeve and the inner sleeve is swirled in one direction around the axis of the combustor by the swirl vanes. Sent in. At this time, since the downstream end of the inner sleeve is arranged on the upstream side of the downstream end of the outer sleeve, the outer sleeve and the inner sleeve are disposed downstream of the downstream end of the inner sleeve. The cross-sectional area of the flow path of the air flow passing through becomes large. Therefore, the flow velocity in the vicinity of the inner sleeve is lower than that in the vicinity of the outer sleeve, and a small vertical vortex is generated in the air flow due to this speed difference. Then, the fuel ejected from the fuel injection nozzle is entrained in the airflow by this small vertical vortex,
The mixing of air and fuel is promoted.

According to the second aspect of the invention, the downstream edge of the swirl vane is formed linearly. As a result, the swirl vanes have a substantially trapezoidal shape, and the degree of change in the velocity of the air flow is substantially uniform from the downstream end of the inner sleeve to the downstream end of the outer sleeve.

According to the third aspect of the invention, the downstream edge of the swirl vane is curved. Thus, by adjusting the curved shape, it is possible to adjust the degree of change in the velocity of the airflow from the downstream end of the inner sleeve to the downstream end of the outer sleeve.

According to the fourth aspect of the invention, a step is formed at the downstream edge of the swirl vane. This allows
The airflow is also disturbed in this step portion, so that the mixing property of the fuel and the air is further improved.

According to the fifth aspect of the present invention, at least the downstream end portions of the outer sleeve and the inner sleeve are gradually reduced in diameter or expanded in the axial direction of the combustor. Accordingly, the airflow flowing between the outer sleeve and the inner sleeve can be guided from the outer side to the inner side in the radial direction of the combustor. Even in this case, since the downstream end of the inner sleeve is located upstream of the downstream end of the outer sleeve, the space between the outer sleeve and the inner sleeve is set downstream of the inner sleeve. A small vertical vortex is generated in the air flow passing therethrough, which promotes the mixing of the fuel ejected from the fuel injection nozzle and the air.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the first to fourth embodiments shown in the drawings. (First Embodiment) FIGS. 1 to 3 show a first embodiment of an air swirler for a gas turbine combustor according to the present invention. In these figures, parts common to those of FIGS. 7 and 8 shown as a conventional example are denoted by the same reference numerals, and the description thereof will be simplified. Here, first, the gas turbine engine will be described. As shown in FIG. 7, a gas turbine engine (gas turbine) 10 has a fan 2 that takes in air and a compressor 3 that compresses the taken-in air in a casing 10a, as in the gas turbine engine 1 of the conventional example. A combustor 11 that mixes fuel with compressed air and burns it; an output turbine 5 that drives the fan 2 and the compressor 3 by the combustion gas generated in the combustor 11; It has a schematic configuration including an exhaust pipe 6 that ejects backward. A plurality of the combustors 11 provided in the gas turbine engine 10 is arranged at equal intervals in the circumferential direction of the gas turbine engine 10.

As shown in FIG. 1, each combustor 11 is disposed on a substantially cylindrical combustion cylinder 12 and a wall surface 12a on the upstream side thereof, and fuel is ejected in the form of mist into the combustion cylinder 12. The injection nozzle 13 and an air swirler 15 that is annularly arranged on the outer peripheral side of the fuel injection nozzle 13 and sends air into the combustion cylinder 12 are configured. Fuel is supplied from the fuel tank to the fuel injection nozzle 13 by a fuel supply mechanism (not shown).

The air swirler 15 includes a cylindrical outer sleeve 16 having an axis parallel to the axial direction of the combustor 11 and a cylindrical inner sleeve 16 which is concentrically arranged inside the outer sleeve 16 with a certain distance. 17 and a plurality of swirl vanes 18 provided between the outer sleeve 16 and the inner sleeve 17 at regular intervals along the circumferential direction. As shown in FIGS. 1 and 2, the downstream end 16a of the outer sleeve 16 and the downstream end 17a of the inner sleeve 17 are shown.
Are arranged so as to face the outer peripheral side of the fuel injection nozzle 13. Then, the downstream end 1 of the inner sleeve 17
7a is located upstream of the downstream end 16a of the outer sleeve 16 in the air inflow direction.
Between these outer sleeve 16 and inner sleeve 17,
In order to impart swirl to the air, as shown in FIG. 2, each swirl vane 18 is provided so as to be inclined and twisted with respect to the axial direction. The downstream edge 18a of each swirl vane 18 is formed in a straight line connecting the end 16a of the outer sleeve 16 and the end 17a of the inner sleeve 17.

Next, the combustor 11 having the above structure.
The operation of the air swirler 15 will be described. As shown in FIG. 1, in the combustor 11, the compressed air sent from the compressor 3 (see FIG. 7) on the upstream side flows between the outer sleeve 16 and the inner sleeve 17 of the air swirler 15, and the swirl vanes are rotated. 1
.. are swung in one direction around the axis of the combustor 11 and fed into the combustion cylinder 12. At this time, since the end portion 17a of the inner sleeve 17 is arranged on the upstream side of the end portion 16a of the outer sleeve 16, a space between the outer sleeve 16 and the inner sleeve 17 is provided downstream of the end portion 17a of the inner sleeve 17. The flow passage cross-sectional area of the air flow passing therethrough is rapidly increased, whereby the flow velocity near the inner sleeve 17 becomes lower than the flow velocity near the outer sleeve 16. Then, FIG. 1 and FIG.
As shown in FIG. 1, the air swirler 1 is operated by the velocity difference between the flow velocity near the inner sleeve 17 and the flow velocity near the outer sleeve 16.
A small vertical vortex (reference numeral (b) in the figure) is generated in the air flow on the downstream side of reference numeral 5 (reference numeral (a) in the figure). On the other hand, when the fuel injection nozzle 13 injects fuel into the combustion cylinder 12 in a mist state, this fuel is mixed with the air flow (a) from the air swirler 15. At this time, the vertical vortex (b) generated in the air flow (a) causes the fuel to be entrained in the air flow (a) to promote the mixing of the air and the fuel. Then, as shown in FIG. 3, at the time of ignition, a mixture of air and fuel is ignited by a spark plug (not shown), and a flame is generated by burning this, and the flame generates a large vortex ( Reference numeral (C) in the drawing is formed.
After the ignition is once performed in this manner, the flame holding, that is, the combustion state is maintained by the vortex (c) of the flame in the combustion cylinder 12, so that it is not necessary to re-ignite as long as the gas turbine engine 10 is continuously operated.

In the combustor 11 of the gas turbine engine 10 described above, the air swirler 15 is provided on the outer peripheral side of the fuel injection nozzle 13, and the downstream end 17a of the inner sleeve 17 of the air swirler 15 is provided. The outer sleeve 16 is located upstream of the downstream end 16a. As a result, a vertical vortex (b) is generated in the air flow (b) which is sent from the compressor 3 and swirls on the downstream side of the air swirler 15, and the vertical vortex (b) causes the fuel injection nozzle 13
The fuel injected from the air is entrained in the air flow (a), and the mixing of the air and the fuel is promoted. As a result, the combustion efficiency of the fuel in the combustion cylinder 12 can be improved, so that the amount of smoke and NOx generated in the combustion gas can be reduced, and high thrust can be obtained. Becomes Further, since the downstream end edge portion 18a of the swirl vane 18 is formed in a linear shape, the swirl vane 18 has a simple trapezoidal shape, and the structure thereof can be simplified. It is possible to easily manufacture the container 15 at low cost. Moreover, the degree of velocity change of the flow velocity in the radial direction of the air swirler 15 becomes substantially uniform,
The generation distribution of the vertical vortex (b) generated on the downstream side of the air swirler 15 can be made standard.

(Second Embodiment) Next, a second embodiment of the air swirler of the gas turbine combustor according to the present invention will be described. Since the only difference between the second embodiment and the air swirler 15 shown in the first embodiment is the shape of the swirl vanes, only the swirl vanes will be described and other common configurations will be described. Is omitted. As shown in FIG. 4 (a), in each of the plurality of swirl vanes 21 provided in the circumferential direction of the air swirler 20, the downstream end edge portion 21 a is the end portion 16 a of the outer sleeve 16 and the end portion of the inner sleeve 17. It is formed in a shape that is curved on the upstream side with respect to the straight line connecting the portion 17a. Air swirler 20 equipped with such swirl vanes 21
In comparison with the air swirler 15 (see FIG. 1), the degree of decrease in the flow velocity in the vicinity of the inner sleeve 17 is large, and as a result, on the downstream side of the air swirler 20, in the vicinity of the inner sleeve 17. A strong vertical vortex is created. As described above, by forming the end edge portion 21a of the swirl vane 21 of the air swirler 20 in a curved manner, the generation distribution of the vertical vortices can be changed, so that the fuel injection amount / velocity, the air flow velocity, etc. By adopting this shape according to various conditions, an ideal combustion state can be obtained. In the second embodiment, the edge 21a of the swirl vane 21 is curvedly formed on the upstream side.
As shown in (b), this may be curvedly formed on the downstream side, and by appropriately determining its shape in accordance with various conditions such as the fuel injection amount / velocity and the air flow velocity, the fuel and air It is possible to improve the mixing efficiency of the above and improve the combustion efficiency.

(Third Embodiment) Next, a third embodiment of the air swirler of the gas turbine combustor according to the present invention will be described. In the third embodiment as well, the only difference from the air swirler 15 shown in the first embodiment is the shape of the swirl vanes, so only the swirl vanes will be described, and other common configurations will be described. The description is omitted. Figure 5
As shown in (a), each swirl vane 26 provided in the circumferential direction of the air swirler 25 has a downstream end edge portion 26.
The stepped portion 27 is formed in a. In the air swirler 25 having such swirl vanes 26, vertical vortices are generated downstream of the downstream end 17a of the inner sleeve 17 and also downstream of the step 27. . As described above, the swirl vanes 26 of the air swirler 25
Since the step portion 27 is formed at the end edge portion 26a of the above, a vertical vortex can be generated also by this step portion 27, and the mixing property of fuel and air can be further improved. In the third embodiment, the swirl vane 26 has a step portion 27.
5B, of course, as shown in FIG. 5B, a plurality of step portions 27 'are formed on the downstream end edge portion 26a' of the swirl vane 26 'to form a multi-step configuration. Good. In the air swirler 25 ′ including the swirl vanes 26 ′, a vertical vortex can be generated on the downstream side of each step portion 27 ′, and it becomes possible to further improve the mixing property of fuel and air.

(Fourth Embodiment) Next, a fourth embodiment of the air swirler of the gas turbine combustor according to the present invention will be described. Note that the difference between the combustor shown in the fourth embodiment and the combustor 11 shown in the first embodiment is only the shape of the air swirler, and here again, only the configuration different from that of the first embodiment is shown. The description will be omitted for other common configurations. As shown in FIG. 6, the air swirler 30 includes a cylindrical outer sleeve 31 having a gradually decreasing diameter along the axial direction of the combustor 11 (see FIG. 1) and a concentric circle inside the outer sleeve 31 with a certain distance. A cylindrical inner sleeve 32 arranged in a shape of
A large number of swirl vanes 3 are provided between the outer sleeve 31 and the inner sleeve 32 at regular intervals in the circumferential direction.
3 and 3. Also in this air swirler 30, the downstream end 32a of the inner sleeve 32 is located upstream of the downstream end 31a of the outer sleeve 31. Further, the swirl vanes 33 are attached so as to be inclined at a constant angle with respect to the radial direction of the axis of the air swirler 30. In such an air swirler 30, the air flowing in between the outer sleeve 31 and the inner sleeve 32 is guided while being swirled from the radially outer side to the inner side of the combustor (not shown). ing.
As a result, the generation state of the flame vortex for flame holding is shown in FIG.
Since it can be different from the air swirler 15 shown in FIG. 3, a good flame holding state can be obtained by adopting this shape depending on various conditions such as the fuel injection amount / velocity and the air flow velocity. . At this time, the end portion 32a of the inner sleeve 32 is located upstream of the end portion 31a of the outer sleeve 31, so that the air swirler 30 of the air swirler 30 is similar to the combustor 11 (see FIG. 1). A vertical vortex can be generated downstream, and the mixing property of air and fuel can be improved. As a result, also by this, the combustion efficiency of the fuel can be improved, so that the amount of smoke and NOx generated in the combustion gas can be reduced and a high thrust can be obtained. Thus, by appropriately determining the shape and angle of the fuel according to various conditions such as the fuel injection amount / velocity and the air flow velocity, it is possible to improve the mixing efficiency of the fuel and air and improve the combustion efficiency. it can.

Incidentally, the air swirlers 15, 20, 25, 25 ', 3 of the combustor 11 shown in the first to fourth embodiments described above.
0 can also be applied to a premix injection valve that is particularly effective in reducing NOx, and in this case as well, the air swirler can promote the mixing of fuel and air. The effect of the injection valve, that is, the reduction of NOx can be more effectively performed.

[0024]

As described above, according to the air swirler of the gas turbine combustor according to the first aspect, the downstream end of the inner sleeve of the air swirler is located closer to the downstream end of the outer sleeve. Is also arranged on the upstream side. This allows
Downstream of the downstream end of the inner sleeve, a small vertical vortex is generated in the air flow that flows between the outer sleeve and the inner sleeve, and this vertical vortex causes the fuel injected from the fuel injection nozzle to flow into the air flow. It is entrained and promotes mixing of air and fuel. As a result, the combustion efficiency of fuel can be improved, so that the amount of smoke and NOx generated in the combustion gas can be reduced, and at the same time,
It is possible to obtain high thrust.

According to the air swirler of the gas turbine combustor according to the second aspect, the downstream edge of the swirl vane is linearly formed. As a result, the swirl vanes have a simple trapezoidal shape, and their structure can be simplified.
It becomes possible to easily manufacture the air swirler at low cost. Moreover, from the downstream end of the inner sleeve to the downstream end of the outer sleeve, the degree of velocity change of the flow velocity of the air flow is substantially uniform, and the distribution of vertical vortices generated on the downstream side of the air swirler is It can be standard.

In the air swirler of the gas turbine combustor according to the third aspect, the downstream edge of the swirl vane is curved. Thus, by adjusting the curved shape, it is possible to change the generation distribution of the vertical vortex from the downstream end of the inner sleeve to the downstream end of the outer sleeve. Therefore, the fuel injection amount / speed,
An ideal combustion state can be obtained by appropriately determining and adopting the shape according to various conditions such as the flow velocity of the air flow.

According to the air swirler of the gas turbine combustor according to the fourth aspect, the step is formed at the downstream edge of the swirl vane. As a result, the air flow is disturbed also in this step portion, and the mixing property of fuel and air can be further improved.

According to the air swirler of the gas turbine combustor according to the fifth aspect, at least the downstream end portions of the outer sleeve and the inner sleeve are gradually reduced in diameter in the axial direction of the combustor. As a result, the air flow can be guided from the outer side to the inner side in the radial direction of the combustor, and the generation state of the vortex of the flame for flame holding can be changed. Therefore, a good flame holding state can be obtained by determining and adopting the shape and angle of the fuel according to various conditions such as the fuel injection amount / speed and the air flow velocity.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of an air swirler of a gas turbine combustor according to the present invention.

FIG. 2 is a perspective view of the same.

FIG. 3 is a front view of the same.

FIG. 4 is a view showing another example of the air swirler of the gas turbine combustor, and is a side sectional view showing a part of the air swirler.

FIG. 5 is a view showing still another example of the air swirler, and is a side sectional view showing a part of the air swirler.

FIG. 6 is a view showing still another example of the air swirler, and is a side sectional view showing a part of the air swirler.

FIG. 7 is a side sectional view showing an example of a gas turbine equipped with an air swirler.

FIG. 8 is a side sectional view showing an example of an air swirler of a conventional gas turbine combustor.

[Explanation of symbols]

 10 Gas Turbine Engine (Gas Turbine) 11 Combustor 13 Fuel Injection Nozzle 15, 20, 25, 30 Air Swirler 16, 31 Outer Sleeve 17, 32 Inner Sleeve 18, 21, 26, 26 ', 33 Swirling Blade 27, 27 '' Step

Claims (5)

[Claims] 1. A combustor of a gas turbine, wherein a cylindrical outer sleeve extends along an inflow direction of air into the combustor, and an inner side of the outer sleeve, the inner sleeve being spaced apart by a certain size. An air swirler including a sleeve and a plurality of swirl vanes provided in the circumferential direction between the outer sleeve and the inner sleeve is provided on the outer peripheral side of the fuel injection nozzle, and the downstream end of the inner sleeve is provided. Is located upstream of the downstream end of the outer sleeve, the air swirler for a gas turbine combustor. 2. The air swirler for a gas turbine combustor according to claim 1, wherein the downstream edge of the swirl vane is
An air swirler for a gas turbine combustor, wherein the downstream end of the outer sleeve and the downstream end of the inner sleeve are linearly connected to each other. 3. The air swirler for a gas turbine combustor according to claim 1, wherein the downstream edge of the swirl vane is
A gas turbine combustor characterized by being curvedly formed either upstream or downstream with respect to a straight line connecting a downstream end of the outer sleeve and a downstream end of the inner sleeve. Air swirler. 4. The air swirler for a gas turbine combustor according to claim 1, wherein the downstream edge of the swirl vane comprises:
An air swirler for a gas turbine combustor, which is formed in a shape having a step portion between a downstream end portion of the outer sleeve and a downstream end portion of the inner sleeve. 5. The air swirler for a gas turbine combustor according to claim 1, wherein at least downstream ends of the outer sleeve and the inner sleeve are along an axial direction of the combustor. An air swirler for a gas turbine combustor, characterized in that the diameter is gradually reduced.