JPS5960127A - Combustor for gas turbine - Google Patents

Abstract

PURPOSE:To suppress the temperature increase of main combustion zone for lowering the emission of NOX, by defining an annular passage for introducing a primary and a secondary airs between an outer and an inner cylinders of the combustor. CONSTITUTION:An air blown-out from the outlet 22 of compressor flows from the rear part of inner cylinder 12 to the top end thereof, as shown by an arrow mark. A part of this outlet air flows from an inlet opening 20 to a secondary annular passage 19 wherein it passes while cooling the peripheral wall of inner cylinder 12, and enters into the second inner cylinder 12 through a wall surface cooling air port 14 and a diluted air port 15. The remaining part of outlet air enters into a main combustion zone 25 of inner cylinder 12 through a primary air port 16 and a secondary air port tube 21 as a primary air and a secondary air respectively. A fuel injected through a fuel nozzle 17 is mixed with the primary and secondary airs to be burnt. A combustion gas from the main combustion zone 25 is mixed in a downstream diluted zone with an air flowed from the diluted air port 15 and the wall surface cooling air port 14, and then flows into a turbine one-stage nozzle 24 through a transition piece 23.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a gas turbine combustor, and more particularly to a gas turbine combustor in which the temperature of the main combustion region is lowered by external forced convection cooling.

[Technical background and problems of the invention]

As shown in FIG. 1, a conventional gas turbine combustor has a combustor outer cylinder 1 and an inner cylinder 2, with an annular passage 3 formed between them. Discharged air 4 from a compressor (not shown) is fed into this annular passage 3 under pressure, and this discharged air 4 flows along the peripheral wall surface in the direction of the arrow while cooling the inner cylinder 2, and a part of the discharged air is used as dilution air. Inner cylinder 2 from dilution air hole 5
Another part of the discharged air 4 flows into the inner cylinder 2 from the wall cooling air holes 6 as wall cooling air, flowing against the inner wall surface. Furthermore, the remainder of the discharged air flows into the inner cylinder 2 through the primary air hole 7 at the tip of the inner cylinder 2.

The liquid fuel injected from the fuel nozzle 8 is mixed with the primary air from the secondary air hole 7 and combusted in the main combustion region 9 to become combustion gas and sent to the gas turbine.

However, in such a conventional gas combustor, after the discharge air 4 exchanges heat with the peripheral wall surface of the inner cylinder 2 while flowing through the annular passage 3 and becomes relatively high temperature, it is discharged from the secondary air hole 7 to the inner cylinder. 2
Because it enters the inside, the temperature of the main combustion area 9 increases and thermal NO.
There was a drawback that x was generated. Further, as the temperature rises, the inner cylinder also becomes hot, which causes a problem of impairing the durability of the inner cylinder.

On the other hand, the conventional gaster-hyf two-stage combustion fan burns a transient mixture of primary air and fuel in the first-stage combustion zone, mixes this combustion gas with secondary air in the transition zone, and then burns the combustion gas in the second-stage combustion zone. This is to perform fuel lean combustion. This two-stage combustor can lower the temperature of the main combustion region more than the combustor described above, but the main combustion region of the two-stage combustor is not cooled by wall cooling air, but is forced convection cooling by primary air with a relatively low flow rate. This has the disadvantage that cooling is insufficient and the temperature rises. There are also known two-stage combustors in which the inner cylinder is heat-insulated by applying a heat-resistant coating to the inner cylinder or by using a ceramic wall surface on the cylinder. However, such a two-stage combustor has the disadvantage that the heat generated inside the inner cylinder is not radiated to the outside, so that the temperature of the scalloped head region becomes high.

[Purpose of the invention]

Therefore, the purpose of the present invention is to suppress the temperature rise in the main combustion region, and
An object of the present invention is to provide a gas turbine combustor that reduces the generation of o□.

[Summary of the invention]

In order to achieve this object, the present invention forms a first annular passage between an outer cylinder and an inner cylinder of a combustor, and also provides a partition wall so as to surround the outer surface of the inner cylinder. A second annular passage is formed between the inner cylinder and the outer surface of the cylinder, and an inlet opening is bored in the partition wall near the tip of the inner cylinder so that the first annular passage and the second annular passage communicate with each other. be.

[Embodiments of the invention]

A second embodiment of the gas turbine combustor according to the present invention will be described below.
This will be explained with reference to the figures.

In FIG. 2, an inner cylinder 2 is housed in an outer cylinder 11 of a gas turbine combustor, and a first annular passage 13 is formed between the outer cylinder 11 and the inner cylinder 12. On the peripheral wall of the inner pipework 2, there are a polygonal wall cooling air hole 4 and a dilution air hole 1.
A primary air hole 16 is formed at the tip of the inner cylinder 2 so as to surround a fuel nozzle 17. Inner cylinder 1
A cylindrical partition wall 18 is provided on the outside of 2 to surround this inner cylinder.
is provided to isolate the first annular passageway 3 from the inner cylinder I2. A second annular passage 19 is formed between the cylindrical partition wall 18 and the inner cylinder 12. An opening for communicating the first annular passageway 3 and the second annular passageway 19 is bored at the tip of the cylindrical partition wall 18 . The cylindrical partition wall 1
A plurality of 1161 secondary air holes #21 are provided in the circumferential direction, which largely penetrate through the inner cylinder 8 and the inner cylinder 2. These secondary nitrogen hole tubes 2It'i and the first ffl-shaped passages 13 are made to communicate directly with the inside of the inner cylinder 12 without communicating with the second annular passage 19. First annular passage 1 near the rear end of 1#12 above
3 faces the compressor outlet 4. Further, the rear end of the inner cylinder 2 is connected to the turbine first stage nozzle 24 by a transition piece.

Next, the operation of the gas turbine combustor according to the present invention will be explained.

Air discharged from the compressor outlet 22 flows through the first annular passage 13
The water flows from the rear of the inner cylinder 12 toward the tip as shown by the arrow. A part of this discharged air flows into the second annular passage 19 from the inlet opening, passes through the second wall passage 19 while cooling the peripheral wall of the inner cylinder 120, and then flows from the wall cooling air hole 14 and the dilution air hole 15. It flows into the inner cylinder 12. The remainder of the discharged air flows from the primary nitrogen hole 16 and the secondary air hole pipe 21 into the main combustion region δ in the inner cylinder 12 as primary air and secondary air. The fuel injected from the fuel nozzle 17 is as described above.
It is mixed with secondary air and combusted. The combustion gas combusted in the main combustion zone 6 is mixed with the air from the dilution air hole 15 and the wall cooling air hole 4 in the downstream dilution zone 26, and passes through the transition vessel 23 to the turbine first stage nozzle. Inflow.

Since the first annular passage 13 is thus separated from the inner cylinder 12 by the cylindrical partition wall 18, both the secondary air and the secondary air flow into the main combustion region of the inner cylinder 12 at relatively low temperatures. Therefore, the temperature of the main combustion region 5 is prevented from increasing. Further, the flow rate of the air passing through the second annular passage 19 is relatively large, and since it flows from the upstream side to the downstream side of the combustor, the peripheral wall of the inner cylinder 12 is effectively cooled.

[Example of the invention]

An embodiment in which the present invention is applied to a two-stage gas turbine combustor will be described with reference to FIGS. 3 to 6. Note that the same members in FIG. 2 are designated by the same reference numerals, and their explanations will be omitted.

In FIG. 3, the cylindrical partition wall 18 covers the outer surface of the inner cylinder J2,
It surrounds the first stage combustion zone 27 upstream, the intermediate transition zone, and the second stage combustion zone 4 downstream. The secondary air hole W21 communicates the II-shaped passage (3) with the transition region of the inner cylinder 12.

FIG. 4 is a sectional view taken along arrow M4 in FIG. 3, and cooling fins 30 (not shown in FIG. 3) are provided in multiple protrusions on the outer peripheral surface of the inner cylinder (2). These cooling fins 30 extend in the axial direction of the combustor.

FIG. 5 is a sectional view taken along the line v--2 in FIG. 3, and clearly shows the positions of the four secondary air hole pipes 21.

Although FIG. 3 should show the upper and lower pipes of the four secondary air hole pipes 21 as cross sections, in order to show the connection of the second current passage 19, the upper secondary air pipe illustration is omitted.

FIG. 6 is a sectional view of IV-11/arrow in FIG.
The rectifying plate 31 provided in the annular passage 19 is disposed near the secondary air hole pipe 21 , more precisely on the downstream side of the secondary air hole pipe 21 , and is arranged in the vicinity of the secondary air hole pipe 21 . The flow velocity of the airflow in the peripheral downstream area is made uniform to prevent disturbance of the desired airflow due to the secondary air hole pipe.

The operation of the two-stage combustor of FIG. 3 will now be described.

In FIG. 3, a part of the air discharged from the compressor outlet 22 flows through the first annular passage 13 and flows into the second monkey-shaped passage 19 from the opening rib of the cylindrical partition 18, and flows into the inner cylinder 12. While cooling the air, it flows outside the first stage combustion zone υ and outside the transition zone I11, and from the wall cooling air hole J4 and the dilution air hole 15 to the second stage combustion zone 29.
flows into. The remainder of the discharged air flows from the primary air hole 16 and the secondary air hole pipe 21 into the main combustion region of the inner cylinder 12, that is, the first stage combustion machine 4 and the transition zone passage. The fuel injected from the fuel nozzle 17 is mixed with primary air in the first-stage combustion zone 27 and burnt in a fuel-rich state, and the combustion gas generated thereby is mixed with secondary air in each transition zone to perform fuel-lean combustion. It mixes with dilution air in the second-stage combustion zone 29 and flows out to the first-stage Tahif nozzle.

At this time, as shown in FIG.
The heat exchange of the air flowing through is promoted, and the inner cylinder 12 is cooled more effectively. The Satoda baffle plate 31 suppresses the air flow from being disturbed by the secondary air hole pipe 21, uniformizes the cold Bl effect of the inner cylinder 12, and reduces the local temperature rise of the inner cylinder 12.

FIG. 7 shows a comparative example of the gas turbine combustor according to the present invention and a conventional gas turbine combustor regarding the temperature distribution on the central glaze of the combustor.

In Figure 7, the horizontal axis represents the distance from the tip of the Viffi burner, and the vertical axis represents the temperature on the 7D axis in the combustor.

The solid line A shows the temperature distribution of the two-stage combustor according to the present invention, the dotted line B shows the temperature distribution of the conventional gas turbine two-stage combustor, and the dotted line C shows the temperature distribution of the conventional gas turbine combustor. express each other. As is clear from this graph, the temperature in the main combustion region of the two-stage combustor according to the present invention is much lower than that of a conventional combustor, and also considerably lower than that of a conventional two-stage combustor. . □Figure 8 shows an embodiment in which the two-stage combustor shown in Figure 3 is further improved.

A second cylindrical partition wall 32 is provided so as to surround the outer surface of the inner cylinder 12 where the transition zone passage and the second stage combustion zone 4 are located.
The cylindrical partition wall 32 forms a third annular passage 33 between the cylindrical partition wall 32 and the inner tubework 2 . This third annular passage 33 is connected to the wall cooling air hole 14.
It is communicated with the inside of the inner cylinder 12 only by. The cylindrical partition wall 18 is provided so that the first stage combustion zone surrounds the outer surface of the inner cylinder part 2 and the second cylindrical partition wall 32, and a second annular partition wall is provided between the inner cylinder 12 and the second cylindrical partition wall 32. A passage 19 is formed. This second annular passage 19 is communicated with the inside of the inner cylinder 12 only through the dilution air hole 5. An inlet opening is formed at the tip of the partition wall 18. The secondary air hole pipe 21 that passes through the partition wall 18, the second partition wall 32, and the inner pipework 2 is connected to the first
The annular passage 3 and the transition zone passage of the inner cylinder 12 are communicated with each other. The third @-shaped passage inlet pipe 34 that penetrates the partition wall 18 and the second partition wall 32 is provided upstream of the secondary air hole g21, and
The @-shaped passage 13 and the third annular passage 33 are communicated with each other.

The discharge air that has entered the third monkey-shaped passage inlet pipe 34 flows through the third annular passage while cooling the inner cylinder 12 of the transition zone passage and the second-stage combustion zone 40 inner cylinder 12, and flows through the wall cooling air hole. ■Flows into the inner cylinder 12 from 4. In addition, the air that has flowed into the inlet opening flows through the second annular passage 19 while cooling the inner cylinder 12 of the first-stage combustion zone 270 and the second partition wall 32, and flows into the inner cylinder 12 from the dilution air hole 5. In this way, after relatively low-temperature discharge air flows into the third annular passage inlet pipe 34, it immediately cools the transition zone passage and the second-stage combustion zone 40 inner cylinder 12, so that the cooling effect is as shown in the example of Fig. 3. Even better than that.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a first annular passage is formed between the outer cylinder and the inner cylinder of the combustor, and a partition wall is provided so as to surround the outer surface of the inner cylinder. A second annular passage is formed between the partition wall and the outer surface of the inner cylinder, and an inlet opening is bored in the soil partition wall near the tip of the inner cylinder to communicate the 133rd-shaped passage with the second annular passage. Therefore, the presence of the partition walls suppresses the temperature rise of the air flowing through the first annular passage, so relatively low-temperature desired air can be supplied to the main combustion region, which avoids high temperatures there and reduces the number of NOx emissions. .

Furthermore, since the inner cylinder wall surface is cooled by the air in the second annular passage, the rise in temperature of the cylinder wall surface itself can be suppressed, and the service life of the inner cylinder can be extended.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view showing a conventional gas turbine combustor.
FIG. 2 is a longitudinal cross-sectional view showing one embodiment of a gas turbine combustor according to the present invention, FIG. 3 is a longitudinal cross-sectional view showing another embodiment of the present invention, and FIG. ■A sectional view taken along the arrows, Figure 5 is a sectional view taken along the ■-■ arrows in Figure 3, and Figure 6 is a sectional view taken along the ■-■ arrows in Figure 5.
7 is a graph showing the temperature distribution on the Ib axis in the combustor, and FIG. 8 is a longitudinal sectional view showing still another embodiment of the present invention. DESCRIPTION OF SYMBOLS 11... Outer cylinder, 12... Inner cylinder, 13... First annular passage, 14... Wall cooling air hole, 15... Dilution air hole, 10... Secondary air hole, 18... ...Bulkhead, 19...
The second annular passage, or... entrance opening. Applicant's representative Kiyoshi Inomata Figure 5 Figure 7 Diagram 1.

Claims (1)

[Scope of Claims] 1. Equipped with an inner cylinder in which a primary air hole is provided at the tip end, and wall cooling air holes and dilution air holes are formed in the rear part of the inner cylinder, and an outer cylinder that surrounds this inner cylinder. and in a gas turbine combustor in which air discharged from the compressor flows through a first annular passage between the inner cylinder and the outer cylinder from the rear part of the inner cylinder toward the front end,
A partition wall is provided to surround the outer surface of the inner cylinder, a second annular passage is formed between the partition wall and the inner cylinder, and an inlet opening is bored in the partition wall near the tip of the inner cylinder. A gas turbine combustor characterized in that a first annular passage and a second annular passage communicate with each other. 2. A second partition wall surrounding the inner cylinders of the transition zone and the second stage combustion zone is provided between the partition wall and the inner cylinder, and a third annular partition wall is formed between the second partition wall and the inner cylinder. Claim 1, wherein the passage communicates with the first J-shaped passage but is isolated from the second annular passage, and communicates with the inside of the inner cylinder via the wall cooling air hole. Gas turbine combustor described in. 3. The gas according to claim 1 or 2, wherein a large number of cooling fins extending in the axial direction of the combustor protrude from the outer surface of the inner cylinder in the second annular passage. Turbine combustor. 4. Claim 1 or 2, characterized in that a secondary air hole pipe communicating the first annular passage and the inside of the inner cylinder is provided to be separated from the second annular passage. The gas turbine combustor according to item 2. 5. A rectifying device is provided to prevent the air flow in the second annular passage from being disturbed by the secondary air hole pipe passing through the second annular passage. The gas turbine combustor described in .