JPH07260148A - Combustion device for gas turbine - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] A combustion device for a gas turbine. By mixing fuel and air at multiple points, the mixability of fuel and air is improved and premixing is performed. Stabilize the combustion state by equalizing the flow velocity inside the tube. A shroud 21 arranged upstream of the premixing pipe 17 and having an annular gap 23 with respect to the outer periphery of the downstream end of the main fuel injection valve 15, and air arranged on the inner surface of the shroud and inserted through the annular gap. A plurality of delta vanes 22 that generate a mixing vortex V near the downstream end of the main fuel injection valve due to the intersection with the flow and are inclined in the circumferential direction are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus for a gas turbine, and in particular, it aims to reduce NOx by improving the mixing property of fuel and air.

[0002]

2. Description of the Related Art FIG. 4 shows a structural example of a gas turbine engine (turbo fan engine) used in an aircraft. In the figure, reference numeral 1 is an air intake port, 2 is a low pressure compressor,
3 is a fan air exhaust duct, 4 is a high pressure compressor, 5 is a combustion chamber, 6 is a high pressure turbine, 7 is a low pressure turbine, 8 is an exhaust duct, and 9 is a casing.

As shown in FIGS. 4 and 5, the combustion chamber 5 is composed of an outer liner 10 and an inner liner 11 inside the casing 9. At a position upstream of the combustion chamber 5, as a gas turbine combustion device, as shown in FIG.
A plurality of 2 are attached at intervals in the circumferential direction, and a larger number of main combustion means (main combustion device) 13 than the pilot combustion means 12 are attached so as to surround the pilot combustion means 12.

An example of the structure of the main combustion means 13 will be described with reference to FIG. 6. The main combustion means 13 is a main fuel injection valve 15 connected to the fuel supply system 14, and the main fuel injection valve 15 is combined and ejected. An air swirler (swirler) 16 for diluting the mixed fuel-air mixture fluid, a premixing pipe 17 for promoting mixing of the diluted fuel, and a premixing pipe 17 connected to the premixing pipe 17 for promoting combustion. It has a main combustion cylinder 18.

The main fuel injection valve 15 has a housing 19
And a base 20. And
The housing 19 has a connection port 19a connected to the fuel supply system 14, a fuel plenum 19b for primary storage of fuel via the connection port 19a, a fuel insertion passage 19c for guiding the fuel downstream, and a base. The ejection sleeve 19d to which 20 is attached in an externally fitted state is arranged, and the ejection sleeve 1
An annular flow path 19e is formed between 9d and the base 20, and an air supply port 19f is formed in the side wall portion of the ejection sleeve 19d. Further, the base 20 is provided with a lip 20a that surrounds the tip end opening of the ejection sleeve 19d with a small annular gap.

In such a gas turbine combustion apparatus, the pilot combustion means 12 is operated to ignite the fuel, and the fuel supply system 14 is operated to burn the main fuel. At this time, the fuel supplied from the fuel supply system 14 to the housing 19 of the main fuel injection valve 15 is the fuel plenum portion 19b, the fuel insertion passage 19c, and the annular passage 1.
The premixing pipe 17 is supplied to the inside of the lip 20a of the mouthpiece 20 in a circular shape via 9e and is sent into the ejection sleeve 19d from the air supply port 19f.
It is ejected in the form of a spray inside. Further, the diluting air is sent from the air swirler 16 into the premixing pipe 17 via the conical tubular air introducing portion 17a, thereby generating the swirling flow R inside the premixing pipe 17, By promoting the mixing of the atomized fuel-air mixed fluid and the diluted air, the temperature rise of the combustion flame F in the main combustion cylinder 18 is suppressed, and the NOx is reduced.

[0007]

However, when a swirl flow is imparted by the air swirler 16 as shown in FIG.
In the inside of the premixing pipe 17, there occurs a phenomenon in which the peripheral flow velocity is increased by the centrifugal force and the central flow velocity is reduced. For this reason, the mixture of fuel and air tends to be insufficient, and the low NOx property is impaired due to uneven mixing. A part having a slow flow velocity is generated in the center of the premixing pipe 17 to cause flashback or self-ignition, thereby lowering the air-fuel ratio. The points to be resolved such as this will remain.

The present invention has been made in view of these circumstances, and improves the mixing property of the fuel and air by mixing the fuel and air at a plurality of points, and the flow velocity inside the premixing pipe. The aim is to stabilize the combustion state by homogenizing

[0009]

In a gas turbine combustion apparatus in which a premixing pipe for promoting mixing of fuel and air is arranged downstream of a main fuel injection valve, the main fuel is arranged upstream of the premixing pipe. A mixing vortex is generated in the vicinity of the downstream end of the main fuel injection valve due to the intersection of the shroud having an annular gap with respect to the outer periphery of the downstream end of the injection valve and the air flow arranged on the inner surface of the shroud and passing through the annular gap. And adopting a configuration including a plurality of delta blades inclined in the circumferential direction. With respect to the annular gap formed between the main fuel injection valve and the shroud, a technique is added in which the cross-sectional area is set to be substantially the same in the upstream and downstream. A plurality of delta blades are provided with a technique of arranging the delta blades at intervals in the circumferential direction and setting adjacent delta blades in line symmetry in the circumferential direction.

[0010]

When the main fuel injection valve is operated, the fuel and air are mixed inside the main fuel injection valve. When air is inserted into the annular gap between the main fuel injection valve and the shroud, the inserted air intersects with the delta wing, and based on the arrangement and shape of the delta wing, a plurality of mixing vortices are formed near the downstream end of the main fuel injection valve. To occur. The mixing vortex intersects the mixed fluid of fuel and air ejected from the downstream end of the main fuel injection valve, and promotes mixing by diluting the mixed fluid individually at a plurality of points. At that time, if the delta blades are inclined in the circumferential direction, mixed vortices are formed in the inclined portions. If the cross-sectional area of the annular gap between the main fuel injection valve and the shroud is set to be approximately the same in the upstream and downstream, the dilution air is supplied to the mixed fluid without deceleration, and the air dilution is facilitated. Planned. By arranging a plurality of delta vanes at intervals in the circumferential direction, mixed vortices inside the annular gap are generated at a plurality of points, and by making adjacent delta vanes symmetrical,
The diluting action of the mixed fluid by the mixing vortex is made uniform.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gas turbine combustion apparatus according to the present invention will be described below with reference to FIGS.

In this embodiment, the main combustion means (main combustion device) is composed of the main fuel injection valve 15 and the premixing pipe 17.
In addition to the above, as shown in FIG. 1, a shroud 21 integrally arranged at a position upstream of the premixing pipe 17, and the shroud 2
A mounting plate 21a for integrally mounting 1 to the base 20 at a plurality of positions at intervals in the circumferential direction, and a plurality of delta vanes 22 integrally arranged on the inner surface of the shroud 21 are provided.

The shroud 21 has a main fuel injection valve 15
It is formed in a conical tubular shape corresponding to the shape of the lip 20a of the mouthpiece 20 and is arranged in a state in which an annular gap 23 is formed with respect to the outer periphery of the lip 20a.

The cross-sectional area of the annular gap 23 between the shroud 21 and the lip 20a is set to be substantially the same in the upstream and downstream, or the downstream position is set to be slightly smaller.

As shown in FIG. 2, a plurality of pairs of the delta vanes 22 are arranged in a vertically raised state and circumferentially spaced with respect to the inner surface of the shroud 21.
Then, as shown by the angle θ in FIG. 3, each delta wing 22 is arranged in a tilted state in the circumferential direction, and the tilting direction is set so as to be line symmetrical in each pair. The angle θ is set to, for example, about 15 to 20 degrees.

In the gas turbine combustion device having such a configuration, when the main fuel injection valve 15 is operated, the fuel from the fuel supply system 14 is supplied to the housing 19 of the main fuel injection valve 15, the fuel plenum portion 19b, The fuel is sprayed into the premixing pipe 17 from the lip 20a of the mouthpiece 20 while being supplied to the fuel insertion passage 19c and the annular flow passage 19e, and air is sent into the ejection sleeve 19d from the air supply port 19f. Is ejected into a shape.

On the other hand, when the diluting air is taken into the annular gap 23 between the lip 20a and the shroud 21,
Since the delta vanes 22 are inclined with respect to the air flow, the air intersects with the plurality of delta vanes 22 and, based on the pressure difference between the upstream and the downstream of the delta vanes 22, the vortex is generated near the edge of each delta vane 22. (Mixed vortices) V are formed respectively.

As shown in FIG. 2 and FIG. 3, the plurality of delta vanes 22 are arranged line-symmetrically at intervals in the circumferential direction, so that they are alternately arranged at a plurality of locations inside the annular gap 23. Symmetrical mixing vortices V having different directions are generated as shown by the arrows in FIG. 2, and affect the flow in the premixing pipe 17 as shown in FIG.

The plurality of mixing vortices V form the lip 20a.
When it intersects with the fuel-air mixed fluid in the form of a spray, the mixing of the dilution air passing through the annular gap 23 and the fuel-air mixed fluid is promoted, and the fuel is diluted. At this time, the diluting action of the mixed fluid is performed in equal amounts at a plurality of locations, and the fuel concentration becomes uniform. By making the fuel concentration inside the premixing pipe 17 uniform, the combustibility is improved, and the rise in the combustion temperature is suppressed, and NOx reduction is achieved.

The mixing vortex V generated by the delta vanes 22 has a stronger mixing action as the velocity increases in the vicinity of the lip 20a. Therefore, the cross-sectional area of the annular gap 23 is set to be substantially the same upstream and downstream. It is possible to supply the diluted air to the mixed fluid without decelerating and smooth the air dilution depending on whether the downstream side is set smaller.

[Other Embodiments] In the present invention, the following technique can be adopted instead of one embodiment. a) Regarding the arrangement of the delta vanes 22, the delta vanes 22 should be inclined only in the circumferential direction. b) Regarding the arrangement of the delta vanes 22, changing the inclination direction every two delta vanes 22 or every three or more. c) As for the shape of the delta wing 22, a combination of different sizes is used. d) Regarding the shape of the delta wing 22, use the delta wing 22 having curved edges.

[0022]

The gas turbine combustion apparatus according to the present invention has the following effects. (1) A shroud having an annular gap with respect to the outer periphery of the downstream end of the main fuel injection valve and a plurality of delta vanes arranged on the inner surface of the shroud and intersecting the air flow are provided. A mixing vortex is generated in the vicinity of the edge and sent into the premixing pipe to sufficiently mix the fuel and air, thereby improving the mixing property and achieving low NOx property. (2) By feeding a plurality of mixing vortices into the premixing tube, the flow velocity inside the premixing tube is averaged, and the occurrence of flashback or autoignition can be reduced and combustion can be stabilized. (3) The cross-sectional area of the annular gap formed by the main fuel injection valve and the shroud is set to be approximately the same in the upstream and downstream, so that the dilution air is sent to the premixing pipe without deceleration and the fuel dilutability is reduced. And NOx can be further reduced. (4) By arranging a plurality of delta blades in the circumferential direction and arranging them in line symmetry in the circumferential direction, the fuel and the air are mixed at a plurality of points to improve the mixing property of the fuel and the air. The air-fuel ratio distribution can be homogenized.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of a gas turbine combustion apparatus according to the present invention.

FIG. 2 is a right side cross-sectional view showing an arrangement state of the delta blades in FIG.

FIG. 3 is a development view showing the arrangement of the delta blades in FIG.

FIG. 4 is a front sectional view showing a structural example of a gas turbine engine (turbo fan engine) used in an aircraft.

5 is a cross-sectional view of the combustion chamber portion of FIG.

FIG. 6 is a front sectional view showing a conventional example of a gas turbine combustion apparatus.

[Explanation of symbols]

 13 Main Combustion Means (Main Combustor) 14 Fuel Supply System 15 Main Fuel Injection Valve 17 Premixing Pipe 18 Main Combustion Cylinder 19 Housing 19a Connection Port 19b Fuel Plenum 19c Fuel Insertion Passage 19d Jet Sleeve 19e Annular Flow Path 19f Air Supply Port 20 Mouth 20a Lip 21 Shroud 21a Mounting Plate 22 Delta Wing 23 Annular Gap V Mixed Vortex

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hidemi Fuji, No. 229, Togaya, Mizuho-cho, Nishitama-gun, Tokyo Ishi Kawashima Harima Heavy Industries, Ltd. Mizuho Plant Co., Ltd.

Claims (3)

[Claims] 1. A combustion apparatus for a gas turbine in which a premixing pipe (17) for promoting mixing of fuel and air is arranged downstream of a main fuel injection valve (15), and the premixing pipe is provided at an upstream position of the premixing pipe. The annular gap (2
3) The shroud (21) in the open state and the air flow arranged on the inner surface of the shroud and passing through the annular gap intersect each other to generate a mixing vortex (V) near the downstream end of the main fuel injection valve, and And a plurality of delta blades (22) inclined in a direction. 2. A main fuel injection valve (15) and a shroud (2)
2. The combustion apparatus for a gas turbine according to claim 1, wherein the cross-sectional areas of the annular gap (23) formed by (1) and (1) are set to be substantially the same in upstream and downstream. 3. The plurality of delta vanes (22) are arranged in a circumferentially spaced manner, and adjacent delta vanes are set to be line symmetrical in the circumferential direction. Alternatively, the gas turbine combustion device according to the item 2.