JPH11343809A - Sealing structure of turbine shroud part for gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the leakage of high pressure gas from a turbine shroud part. SOLUTION: In a turbine shroud part having a turbine casing 2, a turbine shroud 5, a turbine nozzle 6, a partition wall 10 and a shroud support 7, an L-shaped sealing member 22 having a slit in one place of a circumferential direction is disposed in a corner part 21 formed by the first cylindrical wall 10a of the partition wall and the vertical wall 6a of the turbine nozzle, sealing surfaces 20a and 22a are formed in a shroud retainer 20 and the L-shaped sealing member 22 engaged with the end parts of the shroud support 7 and the turbine shroud 5, and an E-seal 23 is disposed between these sealing surfaces 20a and 22a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure for a turbine shroud of a gas turbine.

[0002]

2. Description of the Related Art In recent years, with an increase in the load of a turbine of a gas turbine engine, there has been a tendency that leakage of secondary air from a turbine shroud portion at an outlet portion of a turbine bucket has increased. This is because the gap in the turbine shroud portion becomes large due to thermal deformation.If this leak increases, the amount of secondary air extracted from the compressor increases, which adversely affects engine performance or causes turbine blades There is a problem that the secondary flow in the section is promoted and the turbine performance is adversely affected.

[0003] In this respect, conventionally, except that a seal plate is inserted between the segments of a turbine shroud formed by connecting a plurality of segments in a circumferential direction, a portion between a turbine shroud, a shroud support, and a proximity portion or a contact portion of a turbine casing. Did not provide a positive seal structure. In other words, simply setting the gap between the components to be small makes it possible to expect a seal.

[0004]

For this reason, with the increase in load, the amount of secondary air flowing out from the turbine shroud to the outlet of the turbine rotor blades increases, and the problem that the engine performance deteriorates becomes prominent. Was.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention reduces the amount of secondary air flowing out of a turbine shroud portion to a turbine blade outlet, thereby improving the engine performance of a gas turbine turbine shroud. It is an object of the present invention to provide a seal structure of a part.

[0006]

According to a first aspect of the present invention, there is provided a turbine formed in a cylindrical shape and a ring formed by connecting a plurality of segments in a circumferential direction inside the turbine casing. A shroud, a cylindrical turbine nozzle disposed inside the turbine casing and axially adjacent to the turbine shroud, and protruding from an inner periphery of the turbine casing and located at a boundary between the turbine shroud and the turbine nozzle. A partition wall that partitions a space on the outer peripheral side of the turbine shroud and a space on the outer peripheral side of the turbine nozzle, and is arranged on the outer periphery of the turbine shroud, and is formed in a ring shape by connecting a plurality of segments in a circumferential direction; Turbine shroud section of a gas turbine having a shroud support held by a turbine casing In addition, a ring-shaped shroud retainer for holding the turbine shroud on the shroud support is fitted to an overlapping portion between the axial ends of the shroud support and the turbine shroud on the turbine nozzle side, and an inner peripheral portion of the partition wall is provided. A vertical wall is provided at an axial end of the turbine wall on the turbine shroud side of the turbine nozzle, and the cylinder wall and the vertical wall are brought close to each other, so that a corner facing the inner peripheral side to the vicinity of the partition wall and the turbine nozzle. A ring-shaped L-shaped seal member having an L-shaped cross section abutting the cylindrical wall and the vertical wall at the corner portion and having a slit at one location in the circumferential direction; A seal surface facing the turbine axial direction is formed on the retainer and the L-shaped seal member, and a ring-shaped concave cross-section seal member is disposed between the seal surfaces. Techniques are employed.

In this sealing structure, a corner portion is formed by bringing the cylindrical wall of the inner peripheral portion of the partition wall and the vertical wall of the turbine nozzle close to each other, and an L-shaped sealing member is provided at the corner portion. Since the slit is formed at one location in the circumferential direction of the seal member, the space inside the turbine shroud and the turbine nozzle is a low-pressure first space, the space between the turbine shroud and the turbine casing is a high-pressure second space,
When the space between the turbine casing and the turbine nozzle is a third space of medium pressure, the L-shaped seal member is formed by the pressure of the high-pressure gas (secondary air) in the second space and the cylindrical wall and the vertical wall forming the corner portion. Is pressed against Therefore, gas leakage from the second space to the third space is prevented. Further, since the sealing surfaces facing each other are formed on the shroud retainer and the L-shaped sealing member, and the sealing member having the concave cross section is arranged between the sealing surfaces, the sealing member having the concave cross section is formed by the high-pressure gas pressure from the second space side. When opened, both ends are pressed against the sealing surface, thereby preventing gas leakage from the second space to the first space. In this case, the sealing surface is formed not on the turbine shroud or the shroud support, which is likely to have irregularities and gaps on the end face because of having the connecting portion of the segment, but on the ring-shaped shroud retainer fitted to those ends. The sealing surface of the concave-section sealing member that is pressed against the sealing member can be a continuous smooth surface, and high sealing performance can be maintained regardless of thermal deformation of surrounding elements.

According to a second aspect of the present invention, in the first aspect, between the segments of the turbine shroud, a seal plate for sealing a gap between the segments is provided double on an inner peripheral side and an outer peripheral side. Features. Claim 3
The invention according to claim 1 or 2, wherein a seal plate for sealing a gap between the segments is provided between the segments of the shroud support.

In these seal structures, the seal plate is particularly doubled at a portion having a high pressure ratio, or the seal plate is provided even to the shroud support.
Gas leakage from the space to the first space or the third space can be more effectively prevented.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main part of a turbine shroud part incorporating the seal structure of the embodiment.
FIG. 3 is a partial cross-sectional view of the gas turbine showing a position of the turbine shroud on the gas turbine.

In FIG. 2, L is a turbine axis, 3 is a turbine moving blade, 4 is a turbine stationary blade, and the turbine shroud portion 1 is located on the outer peripheral portion of the turbine moving blade 3. A reference numeral 2 in the figure denotes a cylindrical turbine casing, and a turbine shroud 5 formed in a ring shape by connecting a plurality of segments in a circumferential direction is arranged inside the turbine casing 2. A turbine nozzle 6 having a tapered cylindrical shape is disposed inside the turbine casing 2 so as to be adjacent to the turbine shroud 5 in the axial direction.

Further, on the inner periphery of the turbine casing 2,
A partition wall 10 is provided at a boundary between the turbine shroud 5 and the turbine nozzle 6 to partition a space on the outer peripheral side of the turbine shroud 5 and a space on the outer peripheral side of the turbine nozzle 6.

A shroud support 7 formed in a ring shape by connecting a plurality of segments in a circumferential direction is arranged on the outer periphery of the turbine shroud 5 in the turbine casing 2. The shroud support 7 supports the turbine shroud 5 by being fixed to the turbine casing 2.

Next, the details will be described with reference to FIG. The partition wall 10 protruding from the inner periphery of the turbine casing 2 over the entire periphery is provided with a first inner peripheral portion on the side surface on the turbine nozzle 6 side.
It has a cylindrical wall 10a. On the opposite side, a second cylindrical wall 10b and a third cylindrical wall 10c are provided concentrically from the outer peripheral side, and a ring groove 1 is provided between the second cylindrical wall 10b and the third cylindrical wall 10c.
0d.

The shroud support 7 has a cylindrical portion 7a as a main portion, an end wall 7b extending in the radial direction provided at the end on the turbine nozzle 6 side, and a ring of the partition wall 10 projecting from the end wall 7b. A ring projection 7c fitted in the groove 10d, and an inner peripheral portion protruding from the end wall 7b and having a distal end L
Seal plate 1 having an overlapping wall 7d bent in a shape and sealing a gap between the segments between the segments.
3 is inserted. The seal plate 13 seals the gap between the segments by inserting both ends into the groove on the end face of the segment, and is inserted into the circumferential seal portion 13a inserted into the cylindrical portion 7a and the end wall 7b. It is formed in an L-shaped cross section having a radial seal portion 13b. Then, the turbine nozzle 6 of the shroud support 7
The side end is held by the turbine casing 2 by fitting the ring projection 7c into the ring groove 10d.

The turbine shroud 5 has an overlapping wall 5a on the outer peripheral portion at the end on the turbine nozzle 6 side, which overlaps with the overlapping wall 7d of the shroud support 7. Between the segments of the turbine shroud 5, seal plates 11, 12 for sealing the gap between the segments are inserted doubly. The seal plates 11 and 12 are disposed on the inner and outer peripheral sides, and the gap between the segments is sealed by inserting both ends into the grooves on the end faces of the segments. Part 12a;
A radial seal portion 12b inserted into a portion including the overlapping wall 5a. The radial seal portion 12b of the seal plate 12 of the turbine shroud 5 and the radial seal portion 1 of the seal plate 13 of the shroud support 7
3b is wrapped in the axial direction and the radial direction so as to close the gap between the turbine shroud 5 and the shroud support 7 as much as possible.

Overlapping walls 7d, 5a on the turbine nozzle 6 side of the shroud support 7 and the turbine shroud 5
Are overlapped so as not to be displaced in the axial direction, and a shroud retainer 20 having a U-shaped cross section and a ring shape as a whole is fitted into the overlapped portion from the turbine nozzle 6 side. . Thus, the turbine shroud 5 is supported by the shroud support 7.

On the outer periphery of the first cylindrical wall 10a of the partition wall 10, an outer peripheral cylindrical portion 6b of a vertical wall 6a provided at an end of the turbine nozzle 6 on the side of the turbine shroud 5 is provided with a turbine nozzle 6 and a turbine casing. 2 are fitted so as to allow relative displacement in the axial direction. First cylindrical wall 10 of partition wall 10
a and the vertical wall 6a of the turbine nozzle 6 are close to each other, and a corner 21 facing the inner peripheral side is formed in the vicinity of the vertical wall 6a.

A ring-shaped L-shaped sealing member 22 having an L-shaped cross section which is in contact with the first cylindrical wall 10a and the vertical wall 6a is disposed at the corner portion 21. This L
The shape seal member 22 has a slit (not shown) at one location in the circumferential direction, and the first shape is increased by increasing the diameter in accordance with the internal pressure.
It presses against the cylindrical wall 10a and the vertical wall 6a, thereby sealing the gap between the turbine nozzle 6 and the partition wall 10. In this case, since the outer peripheral cylindrical wall portion of the L-shaped seal member 21 is axially wrapped with the first cylindrical wall 10a, the sealing state is maintained even when the turbine nozzle 6 and the turbine casing 2 are relatively displaced in the axial direction. Can be maintained.

The shroud retainer 20 and the L-shaped sealing member 22 are formed with flat annular sealing surfaces 20a, 22a facing each other at intervals in the turbine axial direction, and are formed between the annular sealing surfaces 20a, 22a. An E-seal (concave section seal member) 23 having an E-shaped section with two concave portions facing the outer peripheral direction is fitted.

The E-seal 23 is opened and deformed in the axial direction when the space on the outer peripheral side separated by the E-seal 23 becomes high pressure and the space on the inner peripheral side becomes low pressure. The outer peripheral space and the inner peripheral space are sealed by being pressed against the sealing surfaces 20a and 22a. Further, the E-seal 23 is in a state of being urged to the open side by the pressure on the high pressure side, and the L-shaped seal member 22 is
It also serves to press against the vertical wall 6a of the turbine nozzle 6.

In the turbine shroud portion configured as described above, the turbine shroud 5 and the turbine nozzle 6
Is a first space K1 through which a low-pressure mainstream gas passes, a space between the turbine shroud 5 and the turbine casing 2 is a second space K2 where high-pressure secondary air exists, and a space between the turbine casing 2 and the turbine nozzle 6. Space is medium pressure third
This is the space K3.

Next, the operation will be described. The high-pressure gas (secondary air) in the second space K2 tends to leak into the low-pressure first space K1 or the medium-pressure third space. At this time, the space 3 between the shroud retainer 20 accommodating the L-shaped seal member 22 and the E seal 23, the turbine nozzle 6, and the partition wall 10 is formed.
Try to leak via 0. However, the partition 10
An L-shaped seal member 22 having a slit in one circumferential direction is disposed at a corner portion 21 formed by the first cylindrical wall 10a and the vertical wall 6a of the turbine nozzle 6, and the shroud retainer 20 and the L-shaped seal are provided. Since the E-seal 23 is provided between the members 22, the first space K1 is moved from the second space K2 side to the first space K1.
The leakage of the secondary air to the side and the leakage of the secondary air from the second space K2 to the third space K3 are prevented as follows.

That is, the pressure of the high-pressure gas (secondary air) in the second space K2 acts on the L-shaped seal member 22 from the inner periphery and acts on the E-seal 23 from the outer periphery. I do. Therefore, the L-shaped sealing member 22 is configured to be connected to the first cylindrical wall 10 forming the corner portion 21 by the gas pressure on the high pressure side.
and the vertical wall 6a is pressed into contact with the vertical wall 6a, whereby a gap between the turbine nozzle 6 and the partition wall 10 is sealed, and leakage of secondary air from the second space K2 to the third space K3 is prevented. The E-seal 23 has an L-shaped sealing member 22 at both ends and both annular sealing surfaces 22 of the shroud retainer 20.
a, 20a, so that the E-seal 23
Is sealed between the inner space and the outer space of the second space K.
Leakage of secondary air from 2 to the first space K3 is prevented.

In this case, the turbine shroud 5 is likely to have irregularities and gaps on the end face due to the segment connecting portion.
Since the annular sealing surface 20a is formed not on the shroud support 7 but on the ring-shaped shroud retainer 20 fitted to the ends thereof, the sealing surface 20a with which the E-seal 23 is pressed against is replaced with a continuous smooth surface. It can be formed as Therefore, high sealing performance can be always maintained irrespective of thermal deformation of the turbine casing 2, the turbine shroud 5, and the like.

In addition, since the double seal plates 11 and 12 are arranged between the segments of the turbine shroud 5 where the pressure ratio is particularly high, and the seal plate 13 is arranged up to the shroud support 7, Leakage of secondary air can be more effectively prevented.

In the above-described embodiment, the E-seal 23 is used as the concave section sealing member. However, if the both ends are pressed against the sealing surfaces 20a and 22a on both sides by the action of the gas pressure on the outer peripheral side, a U-shaped seal is used. A sectional seal may be used.

[0028]

As described above, according to the first aspect of the present invention, a seal member having a concave cross section is provided in order to reduce leakage to the rear part of the turbine blade where the pressure difference is large. Since the L-shaped seal member is provided to reduce leakage to the nozzle portion, it is possible to prevent the gas turbine performance from being deteriorated due to leakage of secondary air. Further, if the seal plate between the segments of the turbine shroud is doubled as in the invention of claim 2, or if the seal plate is also provided between the segments of the shroud support as in the invention of claim 3, Leakage can be more reliably prevented, and gas turbine performance can be improved.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a turbine shroud provided with a seal structure according to an embodiment of the present invention.

FIG. 2 is a partial sectional view of the gas turbine showing a position of the turbine shroud on the gas turbine.

[Explanation of symbols]

 Reference Signs List 2 Turbine casing 5 Turbine shroud 6 Turbine nozzle 6a Vertical wall 7 Shroud support 10 Partition wall 10a First cylindrical wall 11, 12, 13 Seal plate 20 Shroud retainer 20a Seal surface 21 Corner 22 L-shaped seal member 22a Seal surface 23E seal (Concave section seal member) K1 First space K2 Second space K3 Third space

Claims (3)

[Claims] 1. A cylindrical turbine casing, a turbine shroud disposed inside the turbine casing, and formed in a ring shape by connecting a plurality of segments in a circumferential direction, and disposed inside the turbine casing. ,
A cylindrical turbine nozzle axially adjacent to the turbine shroud; and a space protruding from the inner periphery of the turbine casing and located at a boundary between the turbine shroud and the turbine nozzle, and a space on the outer peripheral side of the turbine shroud and the turbine nozzle. And a shroud support disposed on the outer periphery of the turbine shroud and connected to a plurality of segments in a circumferential direction and formed in a ring shape and held by a turbine casing. In the turbine shroud portion of the gas turbine, a ring-shaped shroud retainer for holding the turbine shroud on the shroud support is fitted to an overlapping portion between the shroud support and the axial end portion of the turbine shroud on the turbine nozzle side, and the partition is provided. A cylindrical wall and turbine nose on the inner periphery of the wall The vertical wall is provided at the axial end of the turbine shroud side of the blade, and the cylindrical wall and the vertical wall are brought close to each other, thereby forming a corner portion facing the inner peripheral side in the vicinity of the partition wall and the turbine nozzle, The corner portion has a cross section L that abuts the cylindrical wall and the vertical wall.
A ring-shaped L-shaped seal member having a slit-shaped wall at one location in the circumferential direction is arranged, and the shroud retainer and the L-shaped seal member are formed with sealing surfaces facing each other in the turbine axial direction. A sealing structure for a turbine shroud portion of a gas turbine, wherein a ring-shaped sealing member having a concave cross section is disposed between the sealing surfaces. 2. The gas turbine according to claim 1, wherein seal plates for sealing a gap between the segments of the turbine shroud are provided on an inner peripheral side and an outer peripheral side. Seal structure of turbine shroud part. 3. The seal structure for a turbine shroud part of a gas turbine according to claim 1, wherein a seal plate for sealing a gap between the segments is provided between the segments of the shroud support.