JPH0953462A - Containment ring of gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect casing of a gas turbine, and to improve the cooling performance of a scroll part of the gas turbine. SOLUTION: An annular containment ring 5 is installed between a scroll part liner casing 4 and a turbine casing 3 of a gas turbine 1 having a scroll part 2 of the gas turbine 1 bulged in the periphery of the turbine casing 3. Spaces 6, 7 are provided between the scroll part liner casing 4 and the containment ring 5 and between the containment ring 5 and the turbine casing 3 to be taken as cooling air passages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine, and more particularly to a containment ring in a gas turbine for land and marine vessels.

[0002]

2. Description of the Related Art A gas turbine is composed of an air compressor, a combustor, a turbine, etc., as shown in FIG.
The air compressed by the air compressor burns the fuel in the combustor to generate high-temperature and high-pressure combustion gas. The high-temperature and high-pressure combustion gas drives the turbine, which in turn drives the air compressor to rotate. It has become. In addition, in the gas turbine illustrated in FIG. 3, a large number of combustors are arranged around the gas turbine. However, in the gas turbine for auxiliary power of land and ships, a single turbine is used in view of improvement in maintainability and cost. Many have only a combustor.

In a gas turbine provided with such a single combustor, a spiral space (called a scroll portion) is provided between the air compressor and the turbine, and combustion gas from the combustor is surrounded by the scroll portion. It is distributed in the direction of the turbine and flows into the blades of the turbine almost evenly.

Further, as one of engine type certification standards for land and marine gas turbines (so-called industrial gas turbines), it is required that "fragments of disks due to disk bursts are not scattered outside the gas turbine". For that purpose, the casing itself of the gas turbine may be made thick and strong, but if the casing is made thick, the durability against the thermal stress is reduced, and the casing is damaged only by heat. Therefore, an annular member called a containment ring is provided along the outer circumference of the casing of the gas turbine so as to enclose the turbine disk piece when it is damaged.

FIG. 4 is a partial cross-sectional view of a gas turbine having a conventional containment ring. The gas turbine 1 shown in the figure includes an air compressor 11, a turbine 12, a compressor casing 13, a turbine casing 3, a combustor (not shown), a scroll portion 2, and the like, and air compressed by the air compressor 11 is used. To a combustor (not shown) to combust the fuel to generate combustion gas, which is sent to the turbine 12 through the liner pipe 16 and the scroll part liner pipe 4. The combustion gas sent to the turbine 12 drives the turbine 12, and the turbine 12 drives the air compressor 11 to rotate.

A part of the air compressed by the air compressor 11 is used as cooling air for the scroll liner pipe 4. The air passes between the scroll casing 15 and the scroll liner pipe 4, and flows into the space 17 between the scroll liner pipe 4 and the containment ring 5. Since the containment ring 5 is installed along the turbine casing 3, there is no place for the air flowing into the space 17 to cool the scroll liner pipe 4 by convection of the air flowing into the space 17. There is. Therefore, the containment ring 5 does not play any role during normal operation of the gas turbine.

[0007]

However, in the above-mentioned containment ring of the gas turbine, since the containment ring is installed in close contact with the casing of the gas turbine, its containment coefficient of thermal expansion during operation of the gas turbine is High stress was generated due to the difference, which caused damage to the containment ring and the casing.

Further, since the scroll liner pipe is cooled only by the convection of air flowing into the space between the liner pipe and the scroll casing, the cooling performance is low and the life of the liner is shortened.

The present invention was devised to solve the above problems. In other words, paying attention to the existence of a containment ring that does not play any role during the normal operation of the conventional gas turbine, it can contain the turbine disk piece when the gas turbine is damaged and improve the cooling performance of the scroll part of the gas turbine. It is intended to provide a containment ring for a gas turbine.

[0010]

According to the present invention, a scroll part of a gas turbine is installed between a scroll liner pipe and a turbine casing of a gas turbine provided so as to extend around a turbine casing. An annular containment ring, characterized in that a gap is provided between the scroll liner pipe and the containment ring and between the containment ring and the turbine casing to form a cooling air flow path. A containment ring is provided.

Further, the front end of the above-mentioned containment ring is folded back inward to form a bent portion, and the bent portion is provided with a ventilation hole.

According to the present invention, by providing the gap between the containment ring and the turbine casing, high stress is not generated due to the difference in the coefficient of thermal expansion during operation of the gas turbine.

Further, since the containment ring comes close to the scroll liner pipe, it is possible to form an axial air flow (flow passage) on the surface of the scroll liner pipe and to increase its flow velocity. it can.

The air that has passed through the gap between the containment ring and the scroll portion passes through the ventilation holes provided in the bent portion of the containment ring and flows into the gap between the containment ring and the turbine casing. . Due to the pressure difference between the inside and the outside of the turbine casing, the air flowing into the gap between the containment ring and the turbine casing flows into the turbine casing through the small holes provided in the turbine casing and the gap between the turbine casing.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. In addition, the same reference numerals are given to portions common to the related art, and redundant description will be omitted.

FIG. 1 is a partial cross-sectional view of a gas turbine having a containment ring of the present invention, and FIG. 2 is an enlarged view of the vicinity of the containment ring of FIG. The containment ring shown in FIGS. 1 and 2 is provided with gaps 6 and 7 between the scroll liner pipe 4 and the containment ring 5 and between the containment ring 5 and the turbine casing 3 to provide a cooling air flow path. Is formed.

The front end of the containment ring 5 is folded back inwardly to form a bent portion 8, and the bent portion is provided with a plurality of ventilation holes 9. The bent portion 8 is a flange 18 provided at the end of the scroll liner tube 4.
And turbine casing 3 and scroll liner pipe 4
It is supported by a flange 19 provided on a connecting member 21 for connecting with and an annular connecting member 22 having a groove for connecting these flanges 18, 19. On the other hand, the rear end of the containment ring 5 is provided with flanges 24 and 25 toward the inner side and the outer side. The outer flange 25 is fixed to the scroll casing 15 and the inner flange 24 is fixed to the turbine casing 3 by bolts. ing.

The thickness and material of the containment ring 5 are, of course, designed so as to meet the above-mentioned engine type certification standard of the industrial gas turbine.

A part of the air compressed by the air compressor 11 shown in FIG. 1 passes between the scroll casing 15 and the scroll liner pipe 4, and is passed between the scroll liner pipe 4 and the containment ring 5. It flows into the gap 6 between them. Since the containment ring 5 approaches the scroll liner pipe 4, an axial air flow (flow path) can be created on the surface of the scroll liner pipe, and the flow velocity can be increased.

The air that has flowed into the gap 6 flows along the liner pipe 4 of the scroll portion, and the containment ring 5
Through the ventilation holes 9 provided in the bent portion 8 of the above, and flows into the gap 7 between the containment ring 5 and the turbine casing 3.

The turbine casing 3 has a plurality of small holes 23.
Is provided, and due to the pressure difference between the inside and the outside of the turbine casing 3, the air that has flowed into the gap 7 flows inside the turbine casing 3 (inside the turbine 12). Therefore, the cooling air of the scroll part liner pipe 4 flows through the gaps 6 and 7 without stagnation. The air that has flowed into the gap 7 from the gap, such as the turbine casing 3 that is inevitably generated due to the structure, does not exist in the turbine casing 3.
Needless to say, it flows to the inside (inside of the turbine 12) of.

By thus forming the flow of the cooling air, the air flow can be generated in the axial direction of the turbine casing 3 as well, so that the cooling performance of the turbine casing 3 can be improved.

Further, since the combustion gas flowing in the scroll liner pipe 4 has a high temperature of 1000 ° C. or more and the scroll portion 2 projects around the turbine casing 3, radiant heat of the scroll liner pipe 4 is generated. Due to this, a heat load was applied to the turbine casing 3. By configuring the containment ring 5 as in the present invention, the containment ring 5 can also serve as a heat shield plate.

According to the containment ring of the present invention, not only is it suitable for the engine type qualification standard for industrial gas turbines, but it can also have the cooling function as described above during the operation of a normal gas turbine. .

The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications such as a method for fixing the containment ring and a method for supporting the containment ring can be made without departing from the scope of the present invention.

[0026]

As described above, according to the containment ring of the present invention, since the gap is provided between the containment ring and the turbine casing, the containment ring and the turbine casing have a difference in thermal expansion coefficient from each other. Not affected by. Therefore, damage to the containment ring and the casing can be prevented.

Further, since the cooling air can be made to flow in the axial direction of the scroll liner pipe and the turbine casing, the cooling performance of the scroll liner pipe and the turbine casing can be improved. Further, the containment ring can be provided with a function as a heat shield. Therefore, it is possible to reduce the heat load applied to the scroll liner pipe, the containment ring, and the turbine casing during the operation of the gas turbine, and it is possible to prolong the life of these, and so on.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a gas turbine having a containment ring of the present invention.

FIG. 2 is an enlarged view of the vicinity of the containment ring of FIG.

FIG. 3 is an overall configuration diagram of a gas turbine.

FIG. 4 is a partial cross-sectional view of a gas turbine having a conventional containment ring.

[Explanation of Codes] 1 gas turbine 2 scroll part 3 turbine casing 4 scroll part liner pipe 5 containment ring 6,7 gap 8 bent part 9 ventilation hole 11 compressor 12 turbine 13 compressor casing 14 combustor casing 15 scroll part casing 16 Liner pipe 17 Space 18, 19, 24, 25 Flange 21, 22 Connecting member 23 Small hole

Claims (2)

[Claims] 1. An annular containment ring installed between a scroll liner pipe and a turbine casing of a gas turbine, wherein the scroll portion of the gas turbine is provided so as to project around the turbine casing. A containment ring for a gas turbine, wherein a gap is provided between the partial liner pipe and the containment ring and between the containment ring and the turbine casing to provide a cooling air flow path. 2. The containment ring for a gas turbine according to claim 1, wherein the front end of the containment ring is folded back inward to form a bent portion, and the bent portion is provided with a ventilation hole.