JPH1037704A - Stator blade of gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of the stator blade of a gas turbine, and prevent occurrence of seizure caused by locally producing non-cooled parts, by air-cooling the inside and outside shrouds of the stator blade of the gas turbine. SOLUTION: Cooling air inlet holes 3 for performing air cooling are arranged in an inside shroud 1 and an outside shroud 2. Cooling air outlet holes 5 are arranged in the opposite sides of these cooling air inlet holes 3 through impingement plates 4 having many small diametral passing holes. Hereby, the inside shroud 1 and the outside shroud 2 are cooled by cooling air, the structure of this stator blade of the gas turbine can be simplified, and occurrence of seizure caused by locally producing non-cooling parts can be prevented. Further, cooling air supplied is passed through the impingement plats 4, and exhausted from the cooing air outlet holes 5 to the front surface side of a blade part 6 so as to film-cool the surface of the blade part 6, therefore the cooling air can be effectively utilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine stationary blade capable of effectively performing cooling with a simple structure.

[0002]

2. Description of the Related Art Conventionally, at the high temperature portion of turbine blades of a gas turbine, cooling is performed by discharge air or bleed air of a compressor. However, steam is used instead of air as one of means for improving the efficiency of a gas turbine. It has been considered that the stationary blades of the gas turbine are cooled in such a manner.

[0003] In the steam cooling of the stationary blades of a gas turbine, steam is extracted from a steam turbine which forms a combined cycle in combination with the gas turbine, and the steam pressure is usually high. Also, the leakage of steam into the gas turbine must be extremely low on the steam side cycle.
Therefore, in steam cooling of the stationary blades of a gas turbine, (1) there must be pressure resistance to withstand steam pressure. (2) The steam passage is closed to the outside and has a supply port and a recovery port. (3) Low thermal stress. (4) Being easy to manufacture. Is required.

In a conventional gas turbine stationary blade, as shown by arrows in FIGS. 3 and 4, cooling steam enters the gas turbine stationary blade from a cooling steam inlet 32 of an outer shroud 31 and is impinged on an impingement plate. Upper wing part 3 which passed 39
3 turns at the inner shroud 35 through the inward cooling passage 34, and is collected at the cooling steam outlet 37 through the outward cooling passage 36 provided in the wing 33.

[0005] In addition to the above, there has been proposed a device in which only the inner shroud 35 is air-cooled as disclosed in Japanese Patent Application No. 8-749 filed by the present applicant. That is, in Japanese Patent Application No. 8-749, as shown in FIG. 3, in addition to the above, cooling air is introduced into the inner shroud 35 from the cooling air inlet 40, and the impingement plate 3
The cooling air flows through the inner shroud 35 to cool the inner shroud 35, and the cooled air flows into the main gas flow F from the film cooling holes 38 provided in the inner shroud 35 to cool the film.

[0006]

The current steam-cooled vane of a gas turbine is in the above-mentioned situation and certainly has an advantage in terms of efficiency. However, the closed long bent passage has a structure. It is complicated and difficult to manufacture, and in addition to this, if the wall thickness is increased in order to facilitate the pressure resistance, there is a problem that the entire blade becomes rigid and disadvantageous to thermal stress.

The present invention has been provided to solve the above problems.

[0008]

The stationary blade of the gas turbine according to the present invention employs the following measures.

(1) The inner shroud and the outer shroud are air-cooled.

(2) The rear end of the thin wing portion is air-cooled.

(3) In the present invention of the above (2), a part of the air cooled at the rear end of the wing portion is discharged from the inner shroud side as inner seal air of the combustion gas passage.

According to the present invention (1), the structure is simplified by air-cooling the inner shroud and the outer shroud of the stationary blade of the gas turbine, and non-cooling portions are locally generated to cause burning. Can be prevented.

According to the present invention (2), by cooling the rear end portion of the stationary blade of the gas turbine, which has a thin shape in terms of air performance, with air, the strength is more advantageous than when cooling with high pressure steam. In addition, pin fin cooling becomes possible.

In the present invention (3), the present invention (2)
By discharging a portion of the air that has cooled the rear end of the stationary blade of the gas turbine from the inner shroud side, the inner seal air of the combustion gas passage can be easily secured without complicating the configuration.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the cooling steam flows from the cooling steam inlet 13 on the outer shroud 3 side to the inward cooling passage 8 provided in the blade 6, similarly to the conventional one shown in FIGS. It turns on the inner shroud 1 side through the passage 8, and is collected at the cooling steam outlet 14 through the outward cooling passage 9 provided in the wing 6. However, instead of the cooling steam being supplied into the outer shroud as in FIGS. 4 and 5, the cooling steam is directly supplied to the inward cooling passage 8 of the wing portion 6,
Further, the cooling water is discharged from the outward cooling passage 9 to the cooling steam outlet 14.

The inner shroud 1 and the outer shroud 2 of the stationary blade of the gas turbine are provided with cooling air inlet holes 3 for performing air cooling, and a plurality of small diameter holes are provided on the opposite side of the cooling air inlet holes 3. A cooling air outlet hole 5 is provided through an impingement plate 4 having a through hole.

The rear end 7 of the wing 6 which has a thin shape in terms of air performance corresponds to a pair of inward cooling passages 8 and outward cooling passages 9 for cooling the rear end 7 with air. One air passage 10 provided with a pin fin is provided at a portion where the cooling air flows, and the cooling air flows in the air passage 10 from the outer shroud 2 side to the inner shroud 1 side as shown by an arrow. .

A large number of holes 1 are provided at the tail side of the air passage 10.
1 is provided, and as shown by the arrow, the air passage 10
Main gas flow F in which cooling air flowing through
To join. A hole 12 is also provided on the inner shroud 1 side of the air passage 10 in the blade height direction. Supply port.

In the present embodiment configured as described above, portions other than the rear end 7 of the wing 6 are provided with the inward cooling passage 8.
And cooling by the cooling steam flowing in the outward cooling passage 9.

Further, the inner shroud 1 and the outer shroud 2 are cooled by cooling air flowing in from the cooling air inlet hole 3 and discharged from the cooling air outlet hole 5, so that the structure can be simplified. In addition, it is possible to prevent the occurrence of local uncooled portions and burning. Further, the cooling air supplied into the inner shroud 1 and the outer shroud 2 passes through the impingement plate 4 and is discharged from the cooling air outlet hole 5 to the surface side of the wing portion 6 to cool the surface of the wing portion 6 by film cooling. Thus, the cooling air can be effectively used.

Further, since the rear end portion 7 of the wing portion 6 which is thinner in terms of air performance is cooled by the air flowing through the air passage 10, the strength is more advantageous than when high pressure steam is used. , The cross-sectional area of the air passage 10 is increased,
Further, the thickness of the rear end portion 7 of the wing portion 6 can be reduced, so that effective cooling can be performed and pin fin cooling can be performed.

The cooling air that has cooled the rear end 7 of the wing 6 is provided with a number of holes 11 provided on the tail side of the rear end 7 of the wing 6.
And the cooling air is merged with the main gas flow F, and a part of the cooling air is
The air is discharged inward from the second and becomes the inner seal air of the combustion gas passage, and the inner seal air can be easily secured.

[0023]

According to the vane of the gas turbine according to the present invention, the problem of the conventional steam-cooled vane is reduced by the complicated structure, and the part of the vane is air-cooled. This can solve the problem, and can easily secure the seal air inside the combustion gas passage. Also,
It is advantageous in terms of strength, and it is reasonable for thermal stress. Therefore, the reliability of the gas turbine can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view of a stationary blade of a conventional steam-cooled gas turbine.

FIG. 4 is a sectional view taken along the line BB of FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inner shroud 2 outer shroud 3 cooling air inlet hole 4 impingement plate 5 cooling air outlet hole 6 wing 7 rear end 8 of wing 8 inward cooling passage 9 outward cooling passage 10 air passage 11, 12 hole 13 cooling steam Inlet 14 Cooling steam outlet 31 Outer shroud 32 Cooling steam inlet 33 Wing 34 Inward cooling passage 35 Inner shroud 36 Outward cooling passage 37 Cooling steam outlet 38 Film cooling hole 39 Impingement plate 40 Cooling air inlet F Main gas flow

Claims (3)

[Claims] 1. A vane for a gas turbine, wherein an inner shroud and an outer shroud are air-cooled. 2. A vane for a gas turbine, wherein a rear end of a blade having a thin shape is air-cooled. 3. The gas turbine vane according to claim 2, wherein a part of the air cooled at the rear end of the blade is discharged from the inner shroud side as inner seal air of the combustion gas passage. .