JP2001289060A - Gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas turbine lowering the temperature of combustion gas to reduce NOx by increasing the quantity of combustion air while preventing the occurrence of cooling shortage. SOLUTION: A covering cylinder 30 is disposed around the rear half part of a combustion cylinder 6. A plurality of impingement holes 33 are formed in the covering cylinder. The impingement holes are so formed that the axis is vertical to the combustion cylinder, and air passing the impingement holes and entering a space 34 between the combustion cylinder and the covering cylinder from the inside of a casing 2 is blown almost vertically to the combustion cylinder to impinge-cool the combustion cylinder from the outside. A plurality of inclined holes 35 are formed in the combustion cylinder, piercing a cylindrical body obliquely to connect the outside and inside of the combustion cylinder, in such a manner that the outside opening is positioned avoiding a part on which the impinging air abuts. The air through with impinging-cooling is led into the combustion cylinder through the inclined holes to flow along the inner surface of the combustion cylinder for film cooling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a gas turbine.

[0002]

2. Description of the Related Art Gas turbines are widely used for power generation and various other purposes. This gas turbine injects fuel into air compressed to a high temperature by a compressor and burns in a combustion cylinder to generate combustion gas, which is used to rotate a turbine (rotor blade) to obtain power. is there. In order to increase the efficiency of the gas turbine, the temperature of the combustion gas at the turbine inlet is preferably as high as possible. Conventionally, it has been designed to increase the temperature of the combustion gas.

However, in these gas turbines, nitrogen oxides (NOx) have been developed due to recent tightening of exhaust gas regulations.
Reduction is required. This NOx is generated rapidly as the temperature of the combustion gas increases. Therefore,
In order to reduce NOx, it is necessary to keep the maximum temperature of the combustion gas low.

[0004] Here, it can be considered that the temperature of the combustion gas is basically determined by the amount of air for fuel during fueling, that is, the amount of combustion air.
It becomes higher as the amount of combustion air is smaller. Therefore, NO
In order to reduce x, it is necessary to increase the amount of combustion air.

[0005]

Therefore, of the air sent from the compressor of the gas turbine, the amount of air used not for combustion but for cooling each part is reduced to reduce the amount of combustion air. It needs to be bigger. However, simply reducing the amount of air used for cooling causes insufficient cooling, resulting in reduced durability. The present invention has been made in view of the above,
It is an object of the present invention to provide a gas turbine that improves the utilization of air taken in for cooling and increases the amount of combustion air while preventing the occurrence of insufficient cooling, thereby lowering the temperature of exhaust gas and reducing NOx. Aim.

[0006]

According to the present invention, compressed air supplied from a compressor and fuel injected from a fuel nozzle are burned in a combustion cylinder, and the combustion gas is passed through a stationary blade to a moving blade. A gas turbine that obtains motive power to the combustion cylinder, wherein the combustion cylinder is formed by penetrating through the wall of the coating cylinder to form a double structure by separately covering at least the region including the latter half of the combustion cylinder near the stationary blade, and burning An impingement hole for introducing air substantially perpendicular to an outer surface of a cylinder from a vehicle compartment, and impingement air reusing means for reusing impinge-cooled air for other cooling or combustion air are provided. In the gas turbine configured as described above, when the impinge-cooled air is reused for another cooling, the cooling efficiency is improved and the amount of the cooling air can be reduced, and the amount of the combustion air is reduced accordingly. NOx can be reduced by increasing the combustion temperature and lowering the combustion temperature, and when the impinge-cooled air is reused as combustion air, the combustion air can be directly increased. Therefore, the combustion temperature can also be lowered to reduce NOx.

In order to perform another cooling with the impingement-cooled air, the impingement air reusing means is formed such that the inlet side opening is formed in the outer surface of the combustion cylinder at a position where the impingement air does not hit, and the inner side is inclined so that the inner side is located on the downstream side. Then, the impingement-cooled air flows obliquely into the inside of the combustion cylinder through the inclined hole to cool the combustion cylinder from the inner surface.

In order to reuse the impinge-cooled air as combustion air, the coating cylinder is extended to the upstream end of the combustion air guide cylinder to guide the impingement air to the combustion air intake as an extended coating cylinder. I just need. At this time, if the gap between the combustion cylinder and the coating cylinder is reduced on the downstream side, and the gap between the combustion cylinder and the coating cylinder is increased on the upstream side, the flow of impingement air is improved. At that time, it is preferable that the impingement hole is provided only in the downstream portion where the gap is small, and on the upstream side where the gap is large, a turbulator is provided on the outer surface of the combustion cylinder to perform convection cooling. In addition, if the air cooled on the downstream side of the combustion cylinder is mixed with the impinge air and reused as the combustion air together with the impinge air, the combustion air can be further increased and the NOx can be further reduced.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of a conventional combustor to which the present invention can be applied will be described with reference to, for example, FIG. A combustor 3 is disposed in a casing 2 formed by a casing 1, and high-temperature air compressed by a compressor 4 (only a part is shown) is indicated by an arrow 100 in the casing 2. To be introduced. The combustor 3 includes a combustion tube 6 that burns fuel and air to generate combustion gas, and an introduction unit 5 that guides the fuel and air to the combustion tube 6 to the combustion tube 6. A stator blade 8 is connected to the stationary blade 8 via a seal 7, and a moving blade 9 is disposed downstream of the stationary blade 8.

The introduction section 5 is configured by arranging one pilot nozzle 11 and a plurality of main nozzles 12 inside the inner cylinder 10. The high-temperature compressed air introduced from the compressor 4 into the vehicle interior 2 passes around the inner cylinder 10 toward the upstream side as indicated by an arrow 101, and the combustion air formed at the upstream end of the inner cylinder 10 It is introduced from the inlet 13 into the inner cylinder 10 as shown by an arrow 102. The air introduced into the inner cylinder 10 is turned into swirl air in a swirl flow path 15 having a plurality of swirlers 14, and then the fuel injected from the main nozzle 12 is mixed to form a premixed air. To the combustion tube 6.

The air introduced into the inner cylinder 10 passes through an air passage 11a around the pilot nozzle 11,
Downstream of the pilot nozzle 11, the fuel is diffused and burned together with the fuel injected from the pilot nozzle 11 to generate a pilot flame. This pilot flame is swirl channel 15
And ignites the premixed gas discharged from the combustion chamber. The tip 16 of the pilot nozzle 11 is disposed in a pilot cone 17 that spreads in a megaphone shape.

Hereinafter, embodiments of the gas turbine combustor of the present invention applied to the above-described conventional gas turbine will be described. First, details of the first embodiment will be described. In the first embodiment, the rear end portion of the combustion cylinder in front of the stationary vane is impingement-cooled, and the impinge-cooled air is further used for film cooling of the inner surface of the combustion cylinder. FIG. 1 is a view for explaining the features of the first embodiment, in which a coating cylinder 30 is disposed around the rear half of the combustion cylinder 6 of the gas turbine shown in FIG. 6 whose diameter is reduced. Thus, the coating tube 30 is connected to the combustion tube 6 at the upstream end wall 31 and the downstream end wall 32.

A plurality of impingement holes 33 are formed in the coating cylinder 30 so as to penetrate the cylinder. The impingement hole 33 is formed so that its axis is perpendicular to the combustion cylinder 6, and the air that has entered the space 34 between the combustion cylinder 6 and the coating cylinder 30 from inside the vehicle compartment 2 through the impingement hole 33. (Impinge air) is blown vertically to the combustion cylinder 6
Cool the impingement from the outside.

On the other hand, in the combustion cylinder 6, a plurality of inclined holes 35 penetrating the cylinder obliquely and connecting the outside and the inside of the combustion cylinder 6 are formed so that the outside opening avoids the place where the impinge air hits. Then, the air after the impingement cooling is introduced into the combustion cylinder 6 through the inclined hole 35, flows along the inner surface of the combustion cylinder 6, and suppresses heat transfer from the high-temperature gas on the inner surface of the combustion cylinder 6. That is, film cooling is performed.

The first embodiment operates and operates as described above, so that the cooling efficiency is high. Because it is efficient,
The amount of cooling air can be reduced, and as a result, the amount of combustion air can be increased, and NOx can be reduced.

Next, the details of the second embodiment will be described. In the second embodiment, the coating cylinder 30 in the first embodiment is extended to the upstream end of the inner cylinder 10, and the impingement hole 33 is also formed in the first half of the combustion cylinder 6.
Is obtained by removing the inclined hole 35 formed in the above. FIG. 2 shows the coating cylinder 30 extended, and FIG. 3 shows details of the latter half of the combustion cylinder 6 of the gas turbine of FIG.

The air (impinge air) that has entered the space 34 between the combustion cylinder 6 and the coating cylinder 30 from the interior of the cabin 2 through the impingement hole 33 and is blown vertically to the combustion cylinder 6
Impinge cooling of the whole area from outside. Then, the impingement air that has completed the impingement cooling flows to the upstream side through the space 34 between the combustion cylinder 6 and the coating cylinder 30, and the compressor 4
From the combustion air intake port provided at the upstream end of the inner cylinder 10 together with the air passing directly outside the coating cylinder 30 and directly toward the combustion air intake port 13, enters the inside of the inner cylinder 10, and outputs the combustion air. Will be reused as

The second embodiment operates and operates as described above, so that the air used for cooling is reused as combustion air, the combustion air can be increased, and the combustion gas temperature decreases. The generation amount of NOx can be suppressed.

Next, details of the third embodiment will be described. In the third embodiment, the coating cylinder 30 is extended to the upstream end of the inner cylinder 10 as in the second embodiment, but the gap between the combustion cylinder 6 and the coating cylinder 30 is larger on the upstream side than on the downstream side. Has been bigger. The impingement hole 33 is formed only in the vicinity of the stationary blade 8 where the gap between the combustion cylinder 6 and the coating cylinder 30 is small, and the turbulator (disturbing member) 36 is provided on the outer surface of the combustion cylinder 6 in the upstream part thereof. Is formed, and cooling is performed by disturbing air by the turbulator 36. FIG. 4 shows the extended coating cylinder 30, and FIG. 5 shows details of the latter half of the combustion cylinder 6 of the gas turbine of FIG. 4.

The air (impinge air) that has entered the space 34 between the combustion cylinder 6 and the coating cylinder 30 from inside the cabin 2 through the impingement holes 33 (impingement air), as in the second embodiment.
And the entire area of the combustion cylinder 6 is impinge-cooled from outside. Then, the impingement air that has completed the impingement cooling flows to the upstream side through the space 34 between the combustion cylinder 6 and the coating cylinder 30 while performing convection cooling, passes directly from the compressor 4 through the outside of the coating cylinder 30, and directly. The air enters the inner cylinder 10 from the combustion air intake port provided at the upstream end of the inner cylinder 10 together with the air headed toward the combustion air intake port, and is reused as combustion air. The third embodiment is configured and operated as described above, so that the same effects as in the second embodiment can be obtained.

Next, details of the fourth embodiment will be described. The fourth embodiment is different from the second embodiment in that
The air that has cooled the portion downstream of the combustion cylinder 6 is also reused as combustion air. FIG. 6 is a view for explaining the fourth embodiment, in which shroud cooling air passages 42 and 43 formed inside each of the vane shrouds 40 and 41 supporting the vane 8 are static. Stator blade seal cooling passages 44 and 45 provided outside blade seal 7
Through the space 34 between the combustion cylinder 6 and the coating cylinder 30.

The fourth embodiment is configured as described above, and the air that has cooled the stationary blade shrouds 40 and 41 through the shroud cooling air passages 42 and 43 passes through the stationary blade seal cooling passages 44 and 45. After cooling the vane seal 7, it flows into the space 34 between the combustion cylinder 6 and the coating cylinder 30, and thereafter flows to the upstream side together with the impingement air flowing from the impingement hole 33, and from the compressor 4, The air that passes through the outside of the coating cylinder 30 and directly goes to the combustion air intake port enters the inside of the inner cylinder 10 from the combustion air intake port provided at the upstream end of the inner cylinder 10, and is reused as combustion air. Is done.

Since the fourth embodiment is constructed and operates as described above, the air that has cooled the stationary blade shrouds 41 and 42 and the stationary blade seal 7 also burns more than the second embodiment. The combustion air can be reused as the combustion air, and the combustion air can be further increased, so that the combustion gas temperature can be further reduced and the NOx can be further reduced as compared with the second embodiment.

[0024]

The gas turbine described in each claim burns the compressed air supplied from the compressor and the fuel injected from the fuel nozzle in the combustion cylinder, and the combustion gas is moved to the moving blade through the stationary blade. A covering cylinder body that covers the region including at least the rear half portion of the combustion cylinder at least near the stationary blade to form a double structure, and a combustion cylinder formed through the wall surface of the covering cylinder body An impingement hole for introducing air substantially perpendicular to the outer surface from the vehicle compartment, and impingement air reusing means for reusing impinge-cooled air for other cooling or combustion air, comprising: When the impinge-cooled air is reused for other cooling, the cooling efficiency is improved and the amount of cooling air can be reduced, and the amount of combustion air can be increased and the combustion temperature can be reduced to reduce NOx. Can, impingement cooling It was When reusing air to the combustion air can reduce NOx by also lowering the combustion temperature because it increases the combustion air directly. In particular, according to the third aspect, the air after the cooling of the combustion cylinder is reused for combustion without being guided to the moving blade together with the combustion gas, and the efficiency is not reduced. In particular, according to the sixth aspect, air that has cooled components downstream of the combustion cylinder can be reused as combustion air, and NOx can be further reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing details of a structure for cooling a combustion cylinder according to a first embodiment.

FIG. 2 is a diagram illustrating an entire structure of cooling a combustion cylinder according to a second embodiment.

FIG. 3 is a diagram illustrating details of a structure for cooling a stationary blade according to a second embodiment.

FIG. 4 is a diagram illustrating an entire structure of cooling a combustion cylinder according to a third embodiment.

FIG. 5 is a diagram showing details of a structure for cooling a combustion cylinder according to a third embodiment.

FIG. 6 is a diagram illustrating a cooling structure according to a fourth embodiment.

FIG. 7 is a diagram showing a basic structure around a combustor of a conventional gas turbine to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... Combustor 6 ... Combustion cylinder 7 ... Stator blade seal 8 ... Stator blade 9 ... Moving blade 10 ... Inner cylinder 30 ... Coating cylinder 33 ... Impingement hole 34 ... Space (between combustion cylinder and coating cylinder) 35 ... Inclined hole 36: Turbulator 40, 41: Stator vane shroud 42, 43 ... Shroud cooling passage 44, 45 ... Stator vane cooling passage

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Inada 2-1-1, Shinhama, Arai-cho, Takasago-shi, Hyogo Inside Mitsubishi Heavy Industries, Ltd. Takasago Research Institute (72) Inventor Koji Watanabe 2-5-1 Marunouchi, Chiyoda-ku, Tokyo No. 3 Rishi Heavy Industries, Ltd. (72) Inventor Kazuya Kobayashi 2-1-1, Aramachi-cho, Niihama, Takasago City, Hyogo Prefecture Inside Mitsubishi Heavy Industries, Ltd. Takasago Mfg. Co., Ltd. No. 1 Inside the Mitsubishi Heavy Industries, Ltd. Takasago Factory

Claims (6)

[Claims] 1. A gas turbine which burns compressed air supplied from a compressor and fuel injected from a fuel nozzle in a combustion cylinder and guides the combustion gas to a moving blade via a stationary blade to obtain power. A coating cylinder that covers at least the region including the latter half of the combustion cylinder close to the stationary blade to form a double structure; and air that penetrates the coating cylinder wall and that is substantially perpendicular to the outer surface of the combustion cylinder. A gas turbine, comprising: an impingement hole introduced from a vehicle cabin; and impingement air recycling means for reusing impinge-cooled air for other cooling or combustion air. 2. The impingement air reuse means is an inclined hole which is formed at a location on the outer surface of the combustion cylinder where the impingement air does not come into contact with the impingement air. 2. The gas turbine according to claim 1, wherein the impinge-cooled air is obliquely flown into the inside of the combustion cylinder through the inclined hole to cool the combustion cylinder from the inner surface. 3. The gas turbine according to claim 1, wherein the impingement air reuse means is an extended covering cylinder that extends to an upstream end of the combustion air guide cylinder and guides the impingement air to the combustion air intake. . 4. The gas turbine according to claim 3, wherein the gap between the combustion cylinder and the cladding cylinder is reduced on the downstream side, and the gap between the combustion cylinder and the cladding cylinder is increased on the upstream side. 5. The impingement hole is provided only in the downstream portion where the gap between the combustion cylinder and the coating cylinder is small, and in the downstream portion where the gap between the combustion cylinder and the coating cylinder is large, a turbulator is provided on the outer surface of the combustion cylinder to provide convection cooling. The gas turbine according to claim 4, wherein 6. The air-cooling system according to claim 3, wherein air cooled at a portion downstream of the combustion cylinder is mixed with impinge air and reused as combustion air together with impinge air. Gas turbine.