JPH0473502A - Mechanism of variable air supply for gas turbine combustor - Google Patents

Abstract

PURPOSE:To stabilize the strength of the swirling flow that is formed in the preevaporation space by providing a block ring on one side with many first projection pieces that are arranged substantially radially and a block ring on the other side with second projection pieces nearly L-shaped substantially radially arranged each of which covers one side face of the first projection piece and the outer circumferential face with those second projection pieces arranged substantially radially as well. CONSTITUTION:The base end of a preevaporation pipe 8 is expanded to be shaped like flange, and a block ring 10 is formed integrally with the annular fixing side of the expanded end, and the circular flange section 11 which extends so as to intersect perpendicularly the axial line of the preevaporation pipe 8 and many second projection pieces 12 which are substantially radially directed are formed. On the other hand the outer circumference of a baffle cylinder 5 is provided with the flange section 14 which fits rotatably an annular block ring 13 on the movable side and is positioned opposite to the block ring 10 on the fixed side, and on the flange face of the flange section 14 many first projection pieces 15 that mesh with the second projection pieces 12 are formed substantially radially. Many air channels 22 are formed between the other side faces 15c of the first projection pieces 15 and the side faces 12a of the second projection pieces 12 by the combination of the first projection pieces 15 and the second projection pieces 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a combustor used in a gas turbine such as a gas turbine engine for a vehicle, and in particular to a passage area of an air passage communicating with a pre-evaporation space near a fuel injection nozzle. This invention relates to a variable air mechanism.

Conventional technology In order to reduce NOx emitted from gas turbines, a space for pre-evaporation is provided near the fuel injection nozzle, and the amount of air flowing into this space is adjusted according to the load to cover a wide load range. Gas turbine combustors have been proposed in the past in which the actual air-fuel ratio in the main combustion region is kept constant or within a narrow range.

FIG. 5 shows a combustor described in SAE Vapor 820175 as an example, in which a fuel injection nozzle 33 is attached to one end of a substantially cylindrical combustor body 32 defining a combustion chamber 31, and A pre-evaporation space 34 for pre-mixing and pre-evaporation is provided in front of the fuel injection nozzle 33.

An air conditioning sleeve 35 is disposed to surround this pre-evaporation space 34.

The air conditioning sleeve 35 is shown in detail in FIGS. 6 to 8.
As shown in the figure, there is a fixed sleeve 36 on which a large number of swirler vanes 36a are erected, and the swirler vanes 36a.
has a cylindrical wall 37a that fits around the outer periphery of the cylindrical wall 3;
The movable sleeve 37 has a plurality of openings 37b cut out in the movable sleeve 37a.
7 is rotated within a predetermined angle range by an actuator (not shown) via a gear 38.

That is, the substantial opening area of the large number of air passages 39 between the swirler vanes 36a can be adjusted as appropriate by rotating the movable sleeve 37.

Problems to be Solved by the Invention In the above configuration, air flows through each air passage 39 from the outer circumferential side of the swirler vane 36a toward the inner circumferential side of the swirler vane 36a. - Since the passage opening area is narrowed by the cylindrical wall 37λ on the outer peripheral side of the vane 36a, disturbances such as separation are likely to occur immediately after each air passage 39 flows in. Therefore, there has been a problem in that the strength of the swirl generated by the swirler vane 36a and the flow rate coefficient vary unstably depending on the amount of restriction.

Means for Solving the Problems Therefore, the present invention provides a gas turbine combustor equipped with a pre-evaporation space near a fuel injection nozzle, in which an annular fixed side block is provided so as to surround the outer periphery of the pre-evaporation space. The ring and the movable block ring are arranged to face each other, and the movable block ring is configured to be rotatable by a certain angle, and one block ring is provided with a large number of first protrusions substantially radially, and the other block ring is configured to be rotatable by a certain angle. The block ring is provided with an abbreviated second protrusion piece that covers one side surface and the outer peripheral surface of the first protrusion piece in a substantially radial manner, and the second protrusion piece covers the other side surface of the first protrusion piece and the second protrusion piece. It is characterized by forming a large number of air passages with the inner periphery outlet side serving as the throat section.

Effect: In the above configuration, a large number of air passages are formed substantially radially by combining the fixed block ring and the movable block ring. Air flows through this air passage from the outer circumferential side to the inner circumferential side of the block ring, but when the movable block ring is rotated, the first protruding piece and the second protruding piece
The passage cross-sectional area of each air passage formed between the protruding pieces is narrowed.

Here, since the inner peripheral outlet side is the throat portion with the smallest passage cross-sectional area, disturbances such as peeling are unlikely to occur even when the passage cross-sectional area is narrowed down.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a sectional view showing a main part of a combustor for a gas turbine according to the present invention, in which a heat insulating material 2 is disposed on the inner peripheral side of a casing l having a substantially cylindrical shape, and a casing 1 An end plate 3 is attached to close one end. A fuel injection nozzle 4 is attached to the center of the end plate 3, and a baffle cylinder 5 is attached with bolts 6 so as to surround the fuel injection nozzle 4 in parentheses.

Further, at the inner center of the canong 1, a pre-evaporation pipe 8 for forming a pre-evaporation space 7 is arranged coaxially with the fuel injection nozzle 4. The downstream side of the preevaporation pipe 8 communicates with a combustion space (not shown). The space between the heat insulating material 2 and the preevaporation tube 8 serves as an air passage 9 for introducing combustion air.

Further, the base end of the preevaporation tube 8 is expanded into a flange shape, and an annular fixed side block ring 10 is integrally formed therein. Specifically, the fixed side block ring 10 includes a circular flange portion 11 extending perpendicularly to the axis of the pre-evaporation tube 8, and a plurality of second projection pieces formed approximately radially on the flange surface of the flange portion 11. +2 (see Figure 3).

On the other hand, an annular movable block ring 13 is rotatably fitted to the outer periphery of the baffle cylinder 5.

The movable block ring 13 has a flange portion I4 facing the fixed block ring 10, and on the flange surface thereof, a large number of first protrusion pieces 15 that are combined with the second protrusion pieces I2 are formed approximately radially. It is formed.

Cylindrical portion 13a on the base end side of the movable block ring 13
is formed relatively thick, and as shown in FIG. 2, spring accommodation holes I6 are recessed at three locations, and a coil spring 17 is disposed in a compressed state. The movable block ring 13 is always pressed against the fixed block ring 10 by the coil spring 17, and the entire preevaporation tube 8 is supported between it and the downstream end (not shown). and,
Movable side block ring 13 and fixed side block ring 10
The outer peripheral edge of the louver 18 is clamped and fixed between the two. A chip 19 made of a solid lubricant material such as carbon is interposed at one end of the coil spring 17 that contacts the end plate 3 so as not to impair the smooth rotation of the movable block ring 13. .

Additionally, pivots 20 made of bolts are provided at three locations on the cylindrical portion 13a of the movable block ring 13, and as shown in FIG.
One end of 1 is connected.

The other end of the push-pull rod 21 is linked to an actuator (not shown), which allows the movable block ring 13 to rotate by a predetermined angle.

3 and 4 show the first protrusion piece 15 and the second protrusion piece 1.
2, each of the first protrusions 15 provided on the movable block ring 13 has an elongated sector shape and is slightly inclined with respect to the radial direction so as to function as a swirler. There is. In addition, the second protruding pieces 12 provided on the fixed block ring 10 are individually:
One side surface 15a and outer peripheral surface 1 of the first projection piece 15
It has a substantially I7 shape that covers 5b, and is also formed at a slight inclination with respect to the radial direction.

Therefore, when the first protrusion piece 15 and the second protrusion piece 12 are combined, as shown in FIG. A large number of air passages 22 are formed between the other side surface 15c and the side surface 12a of the second projection piece 12. This air passage 22
is also tilted at a constant angle α with respect to the radial direction,
A swirling flow is generated within the pre-evaporation tube 8 by the air flow from the outer circumferential side to the inner circumferential side. Each of the air passages 22 has an elongated fan shape, and the inner circumferential outlet side is a throat portion 22a having the smallest passage cross-sectional area.

When the movable block ring 13 rotates relative to the fixed block ring 10, the first
The air passage 22 formed between the protruding piece 15 and the second protruding piece 12 is narrowed, and the amount of air flowing in is suppressed. still,
FIG. 4 shows a state in which the movable block ring 13 is rotated by the maximum angle θ to minimize the passage cross-sectional area.

Here, in the above configuration, the basic shape in which the passage cross-sectional area of the air passage 22 is narrowed overall and the inner peripheral outlet side is the throat portion 22a remains unchanged. Therefore, even when the cross-sectional area of the passages is narrowed in this way, the air flow within each air passage 22 becomes very regular, and the generation of separation, turbulence, etc. due to local narrowing is suppressed. Therefore, unnecessary loss does not occur, and the strength of the swirling flow generated within the preevaporation tube 8 can be made very stable.

Note that the gap 23 (see FIG. 4) created when the first protruding piece J5 and the second protruding piece 12 are separated is closed by the outer circumferential wall of the second protruding piece 12 on the outer circumferential side, which is the air inlet side. Therefore, there is no problem.

Effects of the Invention As is clear from the above explanation, the air variable mechanism for a gas turbine combustor according to the present invention has a large number of air passages formed by combining a stationary block ring and a movable block ring. The inner circumference exit side becomes the throat part,
In addition, as each air passage is narrowed as a whole as the movable block ring rotates, separation and turbulence of the airflow can be prevented, and the strength of the swirling flow generated in the pre-evaporation space is extremely stable. It can be done.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main parts of a gas turbine combustor according to the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■, and FIG. 3 is a cross-sectional view also taken along the line ■-■. , FIG. 4 is a sectional view similar to FIG. 3 showing a state in which the air passage is narrowed, FIG. 5 is a sectional view showing an example of a conventional gas turbine combustor, and FIG.
The figure is a sectional view showing a conventional fixed sleeve for air conditioning.
FIG. 7 is a plan view, and FIG. 8 is a sectional view showing a conventional movable sleeve. 4...Fuel injection nozzle, 8...Preevaporation pipe, IO...
・Fixed side block ring, 12...Second protrusion piece, 13
...Movable side block ring, 15...First protrusion piece,
17...Coil spring, 22...Air passage. Figure 5a Figure 5a

Claims (1)

[Claims] (1) In a gas turbine combustor equipped with a pre-evaporation space near a fuel injection nozzle, an annular fixed block ring and a movable block ring are arranged opposite to each other so as to surround the outer periphery of the pre-evaporation space. and arranged so that the movable block ring can be rotated by a certain angle,
And one block ring is provided with a large number of first protrusion pieces in a substantially radial manner, and the other block ring is provided with a substantially L-shaped second protrusion piece that covers one side surface and the outer peripheral surface of the first protrusion piece. Combustion for a gas turbine, characterized in that a large number of air passages are provided substantially radially and between the other side surface of the first protruding piece and the second protruding piece, the inner periphery outlet side serving as the throat part. The air variable mechanism of the container.