JP2002349288A - Cooling structure of combustor guide cylinder of gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure of a combustor guide cylinder of a gas turbine for lengthening a replacing interval of the guide cylinder arranged in a combustor of the gas turbine. SOLUTION: The combustor of the gas turbine provided with the guide cylinder for allowing air to flow in an inner cylinder by projecting in the inner cylinder from a cylindrical side wall of the inner cylinder, and leaks the air from a downstream side wall of a flow of combustion gas in the inner cylinder of the guide cylinder to cool the downstream side wall. Slits or a plurality of holes are arranged in the downstream side wall of the guide cylinder to leak the air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion chamber for a gas turbine, in which a guide cylinder is provided in an inner cylinder for generating combustion gas, and air flows from the guide cylinder into the inner cylinder so that combustion of the combustion gas is uniform. And a cooling structure for a combustor guide cylinder of a gas turbine.

[0002]

2. Description of the Related Art In a conventional gas turbine in which a guide cylinder is provided in an inner cylinder, air flows into the inner cylinder through an annular air passage formed between the outer cylinder and the inner cylinder, and combustion gas in the inner cylinder is formed. The flame holding effect is improved by delaying the flow rate of the main stream (flame) of the flame. A stagnation region in which air stagnates occurs downstream of the main flow of the combustion gas in the guide cylinder. The air in the stagnation region is at a high temperature, and the stagnation region can be a factor that deforms the shape of the guide cylinder. Therefore, conventionally, the guide tube is treated as a consumable item and is replaced at the time of maintenance.

[0003]

Therefore, in the present invention,
It is an object of the present invention to provide a cooling structure for a combustor guide cylinder of a gas turbine, which can eliminate the stagnation region, protect the guide cylinder, and extend the replacement interval.

[0004]

According to a first aspect of the present invention, there is provided a gas turbine having a guide cylinder which projects from the cylindrical side wall of the inner cylinder into the inner cylinder to allow air to flow into the inner cylinder. In the combustor, leak air from a downstream side wall of the flow of the combustion gas in the inner cylinder of the guide cylinder,
The downstream side wall can be cooled. According to a second aspect of the present invention, in the first aspect of the present invention, a slit is provided in the side wall of the guide cylinder on the downstream side of the flow of the combustion gas. According to a third aspect of the present invention, in the first aspect, a plurality of through holes are provided in a side wall of the guide cylinder on the downstream side of the flow of the combustion gas.

[0005]

FIG. 1 is a schematic cross-sectional view of a combustor 50 of a gas turbine 100 capable of implementing the first to third aspects of the present invention. The gas turbine 100 includes a combustor 50,
It is composed of a scroll 12, a turbine 14, and the like.

The combustor 50 has an outer cylinder 5 and an inner cylinder 6, and a flange portion 5 a of the outer cylinder 5 is integrally fixed to the housing 3 of the gas turbine 100 with bolts 15. An annular air passage 11 is formed between the outer cylinder 5 and the inner cylinder 6. Compressed air is supplied to the annular air passage 11 from a compressor (not shown).
It flows inside the annular air passage 11 as 0,21.

A fuel injection valve 16 to which fuel is supplied from a fuel supply pipe 9 is provided at an upper end of the inner cylinder 6. An air inlet 2 having a swirl vane 1 is provided around the fuel injection valve 16.
Is provided. Further, a spark plug 10 is provided above the inner cylinder 6.
Is installed. Fuel is injected from the fuel injection valve 16, air in the annular air passage 11 flows from the air inlet 2 into the inner cylinder 6, and the fuel and air are mixed to form an air-fuel mixture. The fuel is ignited by 10 and burns to produce combustion gas.

FIG. 2 is a view taken in the direction of arrows II-II in FIG. FIG.
As shown in FIG. 2, a plurality (for example, four as shown in FIG. 2) of holes 18 are provided in the upper cylindrical side wall of the inner cylinder 6 in the circumferential direction. The guide cylinder 7 extending inside the inner cylinder 6 is fixed to the hole 18 by welding. The side wall on the downstream side of the flow of the combustion gas in the guide cylinder 7 (the lower side in FIG. 1 and the front side in FIG. 2) is in the longitudinal direction of the guide cylinder 7 (that is, in the radial direction of the inner cylinder 6). ), Or a plurality of holes 31 arranged in the longitudinal direction of the guide cylinder 7.

Further, as shown in FIG. 1, a dilution air inlet 8 for taking in dilution air for lowering the temperature of the combustion gas is provided on the cylindrical side wall further downstream of the inner cylinder 6.
The lower end of the inner cylinder 6 is connected to the inlet of the scroll 12, and the outlet of the scroll 12 is provided with a nozzle flange 22 fixed to the housing 3 and a nozzle 13 welded to a turbine shroud 23.

Further downstream of the nozzle 13 is the turbine 1
4 are arranged. After rotating the turbine 14, the combustion gas flowing from the nozzle 13 is discharged to the outside via the exhaust passage 4 as exhaust gas.

FIG. 3 (a) is a front view of a conventional guide cylinder 7a showing the flow of combustion gas, and FIG. 3 (b) is the present invention showing the flow of combustion gas and the like. FIG. 2 is a front view of a guide cylinder 7 of the second invention).

3 (a) and 3 (b), the guide cylinders 7a, 7
Air flows toward the near side of the drawing (flows into the inner cylinder 6), but in FIG. 3A, a stagnation region 60 where the combustion gas stagnates occurs downstream of the flow of the combustion gas. The air (combustion gas) in the stagnation region 60 has a high temperature, and if the high-temperature air stays for a long time, the guide cylinder 7a may be damaged (burned).

In FIG. 3B, a part of the air in the guide tube 7 leaks through the slit 30 and flows out of the side wall of the guide tube 7 as an air flow 62 before reaching the tip of the guide tube 7. I do. The air flow 62 eliminates the stagnation region 60 in FIG. 3A and can prevent the guide cylinder 7 from being partially heated. The guide cylinder 7 is formed of the same heat-resistant material as the inner cylinder 6 (for example, IN601).

FIG. 2 shows an example in which the slit 30 is provided from the inner wall (root) of the inner cylinder 6 to the tip thereof.
0 may be provided at least as long as the stagnation area 60 shown in FIG. 3A can be eliminated. Hole 31
Similarly to the slit 30 (FIG. 2), it is provided so that the stagnation region 60 can be eliminated (the size and the number are set).

FIG. 2 shows an example in which four guide cylinders 7 are provided. However, the number is appropriately changed according to the type, size, application, and the like of the gas turbine 100, so that combustion in the inner cylinder 6 is uniform. Care should be taken to maintain the environment in which the activities take place. FIG.
In the above, an example in which two guide cylinders 7 provided with the slits 30 and two guide cylinders 7 provided with the holes 31 are provided in the inner cylinder 6 has been described.
Only the slits 30 may be provided in all the guide cylinders 7, or conversely, only the holes 31 may be provided in all the guide cylinders 7.

[0016]

According to the present invention, the guide cylinder 7 is provided so as to perform uniform combustion in the inner cylinder 6, and the guide cylinder 7 is provided so that the effect of the guide cylinder 7 is maintained (that is, the replacement interval can be lengthened).
According to the first aspect of the present invention, a part of the air flowing through the inside can be ejected from the downstream side of the main flow of the combustion gas.
The stagnation region 60 does not need to be generated on the downstream side of the flow of the combustion gas, and it is possible to prevent the guide cylinder 7 from being damaged by the high-temperature gas.

According to the second aspect of the present invention, since the slit 30 is provided in the guide cylinder 7, the guide cylinder 7 can be easily processed and manufactured at low cost.

According to the third aspect of the present invention, since the plurality of holes 31 are provided in the guide cylinder 7, the guide cylinder 7 provided in the existing combustor 50 can be easily processed. The rigidity of the guide tube is higher than that in the case where the slit 30 is provided, and in the case of the newly provided guide tube, welding distortion hardly occurs when welding to the inner tube 6.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a combustor of a gas turbine in which the inventions of claims 1 to 3 can be implemented.

FIG. 2 is a view taken in the direction of arrows II-II in FIG.

FIG. 3 (a) is a front view of a conventional guide cylinder showing a flow of combustion gas. (B) is a front view of the guide cylinder of the present invention (the inventions of claims 1 and 2) showing the flow of the combustion gas and the like.

[Explanation of symbols]

 Reference Signs List 3 housing 5 outer cylinder 6 inner cylinder 7 guide cylinder 11 annular air passage 18 hole 30 slit 31 hole 50 combustor 60 stagnation region 61 combustion gas flow 62 air flow 100 gas turbine

Claims (3)

[Claims] In a gas turbine combustor provided with a guide cylinder projecting from a cylindrical side wall of the inner cylinder into the inner cylinder and allowing air to flow into the inner cylinder, a downstream side of a flow of combustion gas in the inner cylinder of the guide cylinder is provided. Air is leaked from the side wall on the side, and the side wall on the downstream side is made coolable. 2. The structure for cooling a combustor guide cylinder of a gas turbine according to claim 1, wherein a slit is provided in a side wall of the guide cylinder on the downstream side of the flow of combustion gas. 3. The cooling structure for a combustor guide cylinder of a gas turbine according to claim 1, wherein a plurality of through holes are provided in a side wall of the guide cylinder on a downstream side of a flow of combustion gas.