JPH11229804A - Steam cooled gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable efficient recovery of steam that leaks from a seal on a supply side by supplying steam from the center area of the rotating shaft such that the steam is recovered from the outside, and furthermore, to also enable the recovery of heat extension. SOLUTION: The steam 30 on the supply side is supplied to a cavity 27 from within a cylinder 10. The steam 30 then passes through a groove provided in the coupling surface 26 of the turbine main shaft 1 of a four-step disc 24, and then passes from a supply duct 15 through supply ducts 11a, 12a so as to be supplied to rotor blades 11, 12. The steam 31 on the recovery side after cooling passes from the recovery ducts 11a, 12b through a recovery duct 16, a radial recovery duct 17, and an axial recovery duct 18 where it is recovered from a hole. In the turbine main shaft 1, the coupling surface 26 side becomes cool and the opposite side becomes hot. As a result, the abutted surface 26 closes due to the thermal stress, thereby preventing leakage of the steam 30 on the supply side. Also, the turbine main shaft 1 is sealed by a static side seal 4a and a rotary side seal 4b such that steam which leaks from the seal is efficiently recovered. Axial movement is possible by a piston ring of the cylinder 10 and a centering piece 6 such that the thermal stress is absorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam-cooled gas turbine having a structure for preventing leakage of steam for cooling.

[0002]

2. Description of the Related Art FIG. 11 is a sectional view of a gas turbine employing a conventional typical steam cooling system. In the figure, 5
0 is a compressor, 51 is a gas turbine, and the gas turbine 51 has moving blades 71, 7 provided around a rotor 60.
2, 73 are provided, and the high-temperature combustion gas flows into the combustion gas passage 52 and flows therethrough, and the stationary stationary vanes 83, 84, 85 are provided.
The rotor blades 71, 72, 73 rotate between them to rotate the rotor 60.

A steam passage 63 communicates with the rotor disk 61 and penetrates in the axial direction. A plurality of steam passages 63 are provided in the circumferential direction. The cooling steam 80 is guided to the steam passage from the steam inlet 65 of the shaft 64, passes through the passage 62, enters the cavity 66, enters the two-stage bucket 72 from the supply-side passage 67, cools the blade, and cools the blade. The vapor flows out of the recovery side passage 68 into the cavity 69. On the other hand, the steam in the steam passage 62 enters the supply-side passage 91 from the cavity 90, flows into the first-stage bucket 71 from here, and cools the inside of the blade,
The cooled steam flows out of the recovery-side passage 92 into the cavity 69, merges with the recovered steam flowing out of the preceding two-stage bucket 72, flows out into the cavity 93, and passes through the center of the rotor 60 to the shaft 64 side. To be collected. In addition, steam passage 6
Some of the steam from 2 passes through cavity 94 and
It is also supplied to the 0 side and is provided for cooling.

Gas turbines employing the above-described steam cooling system have become effective cooling systems for gas turbines as a number of combined cycle plants have been constructed with the increase in temperature and efficiency of power plants in recent years. The adoption of an air-cooling method is being considered as a method. In particular, in a combined plant, a part of the steam generated by the steam turbine is extracted and guided to the gas turbine, the gas turbine is cooled, the steam whose temperature has increased after cooling is collected, returned to the steam turbine side, and used effectively. Therefore, it contributes to the efficiency improvement of power plants and has attracted attention in recent years.

In such a conventional steam cooling system, since low-temperature and high-pressure steam is supplied from around the rotor, there are many leaks to the outside low-pressure side during the supply. How to prevent this is a major issue in steam cooling systems.

FIGS. 9 and 10 are views showing another example employing a steam cooling system. FIG. 9 is a cross-sectional view showing the rear of a four-stage rotor blade.
1, a rear disk 102 (journal bearing) is mounted, and an outer rotary shaft 103 and an inner rotary shaft 108 are mounted on the rear disk 102. The rear disk 102 rotates together with the four-stage disk 100. Reference numeral 105 denotes a stationary housing. The outer rotating shaft 103 is a bearing 105 serving as a seal. The inner rotating shaft 108 is a bearing 107 also serving as a seal. The bearing 105 is provided to face the rotating side. 106 is a high-pressure chamber, 109 is an annular passage, which serves as a steam passage, and is formed between the outer rotating shaft 103 and the inner rotating shaft 108.

In the steam turbine of the steam cooling system having the above structure, the supply-side steam 120 passes through the annular passage 109 from the chamber 106, enters the annular high-pressure chamber 110, and passes through the passage 111.
Through the cavity 112, and from there through a not-shown passage provided in the four-stage disc 100,
It is led to the two-stage bucket. The air that has cooled the rotor blades passes through the inside rotation shaft 108 (not shown) and is collected as the recovery-side steam 121.

FIG. 10 is an enlarged view of the rear disc 102 in FIG. 9. In FIG. 10, the seal disk 101 side is heated by the high-temperature recovery-side steam 121 and is higher in temperature than the opposite side. . For this purpose the rear disc 10
In No. 2, the sealing disk side is affected by the thermal expansion, and the fastening bolt 113 is pulled as shown by the arrow, causing a tilt.
As a result, a part of the supply-side steam 120 leaks to the outside from the gap created by the inclination.

[0009]

As described above, FIG.
In the gas turbine employing the conventional typical steam cooling system shown in (1), steam extracted from the steam turbine side passes through disks from a plurality of steam passages provided around the rotor, and is guided to the moving blade, and the moving blade is The cooled, high-temperature steam after cooling is guided from the cavity to the center of the rotor, collected from the center of the rotor, returned to the steam turbine side, and used effectively. However, in the conventional steam cooling system as described above, since the low-temperature and high-pressure steam is supplied from around the rotor, there are many locations that leak to the outside low-pressure side during the supply, so that many seal portions need to be provided. . Therefore, how to prevent high-pressure supply steam from leaking to the low-pressure side has been a major issue in the steam supply system.

Also, in the example shown in FIG. 10, the rear disk (journal bearing) 102 is exposed to the recovery-side steam 121 passing through the coupling surface between the rear disk 102 and the disk, so that the temperature becomes high. The journal bearing is thermally deformed and the outer peripheral side is opened, and a part 120 a of the supply side steam 120 is
Will be leaked. In addition, the deformation may cause an excessive tensile stress in the disk fastening bolt 113. Further, also in this example, the supply-side steam 120 is outside the recovery-side steam 121, and the outer rotating shaft 103, which is the rotating side, and the bearings 105, 107, which are the sealing portions on the stationary side.
From the pump, and therefore the amount of steam supplied to the bucket will be reduced.

In view of the above, the present invention provides a steam-cooled gas turbine which has a structure in which steam on the supply side supplied to the moving blade is less leaked to the outside, and a structure which easily absorbs the amount of elongation due to the thermal deformation is capable of generating a gap due to the thermal deformation. It is an object of the present invention to provide a steam-cooled gas turbine capable of reducing steam leakage and improving steam recovery efficiency.

[0012]

The present invention provides the following means (1) to (6) in order to solve the above-mentioned problems.

(1) A plurality of steam supply passages in the main shaft for supplying steam in the axial direction from the rear end of the turbine main shaft, and steam is guided into the disk from each of the steam supply passages in the main shaft, and the disk is supplied to the rotor blades. A steam supply passage, and a steam recovery passage in the disk for guiding and recovering the steam that has cooled the moving blades, and a steam in the main shaft communicating with the steam recovery passage in the disk for recovering the steam after the cooling of the moving blades. A steam-cooled gas turbine having a recovery passage, wherein the main shaft steam supply passage passes through a center portion of the turbine main shaft, and the main shaft steam recovery passage passes through an outer periphery of the main shaft steam supply passage. Steam-cooled gas turbine.

(2) In the invention of the above (1), a plurality of radial grooves are provided in a radial direction on a joint surface of the final stage disk with the main shaft, and the disk-side steam supply passage and the main shaft-side steam supply passage are respectively provided. Steam cooling, wherein a radial radial steam recovery passage is provided on the turbine main shaft side behind the joint surface, and the disc-in-disk steam recovery passage and the main-shaft steam recovery passage are connected. Turbine.

(3) The steam-cooled gas turbine according to the invention (1), wherein a heat-sealing cylinder is provided on the outer inner peripheral wall surface of the steam recovery passage in the main shaft while keeping a predetermined space.

(4) In the invention according to the above (1), the rotary shaft is connected to the rear end of the steam recovery passage in the main shaft, forms a part of the steam recovery passage in the main shaft, and has a plurality of fins around its outer periphery. A stationary cylindrical member that covers the outer periphery of the side cylindrical seal member and the rotating side cylindrical seal member, and has a plurality of fins on its inner peripheral surface that face the fins of the rotating side cylindrical seal member to form a seal portion. A steam-cooled gas turbine, comprising: a cylindrical seal member; a rotary cylindrical seal member; and a centering cylindrical member for fixing a rear end of the steam supply passage in the main shaft.

(5) In the above invention (1), a support member is provided between the inner surface of the steam recovery passage in the main shaft and the outer circumferential surface of the steam supply passage in the main shaft at a predetermined gap in the circumferential direction, and the main shaft is provided with a predetermined gap. A steam-cooled gas turbine, wherein both ends of an inner steam supply passage are slidable in an axial direction.

(6) In the above invention (1), a groove is provided between the forward end portion of the steam supply passage in the main shaft and the turbine main shaft around the outer periphery of the steam supply passage in the main shaft, and a piston ring is provided. A steam-cooled gas turbine characterized by being inserted.

In (1) of the present invention, since the supply-side steam passes through the center of the turbine main shaft, the supply-side steam is inside the recovery passage, and the amount of steam leaking outside is reduced. Conventional steam is supplied from the outside of the turbine main shaft and recovered from the inside.Therefore, the amount of steam supplied from the stationary and rotating side seals is large, and the amount of steam supplied to the rotor blades is large. Although reduced, in the present invention, the steam is supplied through the inside of the recovery side, so that there is no leakage from the seal portion as in the related art.

Further, in (2) of the present invention, since the steam recovery passage is on the downstream side of the joint surface between the disk and the turbine main shaft, the high-temperature recovered steam flows on the rear side, and the steam is recovered between the disk and the turbine main shaft. The joining surface serves as a flow path for low-temperature steam on the supply side. Therefore, the joint surface acts to close due to thermal deformation, thereby preventing the steam from leaking from the joint surface. In the conventional structure, high-temperature recovered steam flows through the joining surface, the joining surface side becomes high temperature, and the joining surface receives thermal deformation and acts to open. However, in the present invention, such opening is prevented.

In (3) of the present invention, the outer inner peripheral wall surface of the steam recovery passage of the turbine main shaft keeps a predetermined space, and the space is filled with, for example, steam or air to keep the gas layer. It makes it difficult to transfer the heat of the steam to the bearing side. Thereby, burning of the oil can be prevented.

In (4) of the present invention, a seal is constituted by the rotating-side cylindrical sealing member and the stationary-side cylindrical sealing member,
Sealing is ensured, and the centering cylindrical member facilitates assembly.

In (5) of the present invention, the space between the steam recovery passage and the steam supply passage in the main shaft is supported by the support member, and both ends are supported so as to be slidable in the axial direction. Can absorb thermal expansion.

In (6) of the present invention, the space between the front end of the steam supply passage in the main shaft and the turbine main shaft is sealed by a piston ring to prevent leakage to the steam recovery passage in the main shaft.
In addition, it is possible to absorb the elongation by making it movable with respect to the thermal elongation in the axial direction.

[0025]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is an overall sectional view of a steam-cooled gas turbine according to one embodiment of the present invention. In the figure, a turbine rotor disk 21,
A first stage rotor 11, a second stage rotor 12, a third stage rotor 13 and a fourth stage rotor 14 are attached to 22, 23 and 24, respectively. The disks 21 to 24 and the turbine main shaft 1 are fastened with fastening bolts. At 25, they are mutually connected in the axial direction.

The turbine main shaft 1 has four coupling surfaces 26.
It is mounted in contact with the step disk 24 and is rotatably supported by the oil-filled bearing 2. A thermal shield 3 is attached inside the turbine main shaft 1,
An outer cylinder seal 5 is axially attached to an end face of the turbine main shaft 1 by a coupling bolt 7, and an end is fixed to the inner cylinder 10 by a centering piece 5. Reference numerals 4a and 4b denote a stationary-side seal and an outer cylinder-side (rotation-side) seal that are disposed to face each other.

A strut support 8 is provided between the thermal shield 3 and the inner cylinder 10 to form a space.
Further, a strut support 9 is provided at an end of the inner cylinder 10 on the cavity 27 side so as to be slidable in the axial direction.

A supply passage 11a and a recovery passage 11b are provided in the first-stage moving blade 11, and a supply passage 12a is also provided in the second-stage moving blade 12.
And a recovery passage 12b. As will be described later with reference to FIGS.
The collection passage communicates with the collection passage 16. The supply passage 15 communicates with a groove provided on the coupling surface as described later and is connected to the cavity 27.
7 is connected to the axial supply passage 19. The collection passage 16 communicates with a radial collection passage 17 as shown, and the radial collection passage 17 is connected to an axial collection passage 18.

In the steam-cooled gas turbine having the above-described structure, the supply-side steam 30 passes through the inner cylinder 10 and passes through the cavity 2.
7 and flows into the supply passage 15 from the cavity 27 through a groove provided on the coupling surface 26 of the coupling surface of the turbine main shaft 1. The supply passage 15 enters the cavity 28 and passes therethrough through the supply passage 11a.
And flows through the cooling steam passage in the rotor blade 11, enters the cavity 29 a through the recovery passage 11 b, and flows out of the cavity 29 a from here.

The steam from the supply passage 15 flows into the supply passage 12a from the cavity 29b, enters the two-stage moving blade 12, flows through the cooling steam passage in the blade, and passes through the recovery passage 12b.
Through the cavity 29a.
In this case, the recovered steam from the first-stage bucket 11 is combined with the recovered passage 1
Outflow to 6.

The recovery-side vapor from the recovery passage 16 passes through the radial recovery passage 17 and the axial recovery passage 18, and flows out of the outlet 5a of the outer cylinder seal 5 to the outside as shown in FIG. Collected in the steam recovery system. According to the steam-cooled gas turbine of such an embodiment, the supply-side steam 30 is supplied from the center side of the rotor, and the recovery-side steam 31 is recovered from the outside thereof. The recovery side is reversed, so that the vapor on the supply side does not easily leak to the outside. Next, a configuration in which the supply-side steam is less likely to leak will be described in detail.

FIG. 2 shows details of the coupling portion of the turbine main shaft in FIG. 1, (a) is a cross-sectional view, and (b) is an explanatory view of deformation due to thermal stress. In FIG.
The fourth stage disk 24 and the turbine main shaft 1 are in contact with each other at a coupling surface 26 and are connected by fastening bolts 25. The supply-side steam 30 is low-temperature steam for cooling, and the four-stage disk 2
4 is supplied to the rotor blades through the grooves provided in the coupling surface 26.

On the other hand, the recovery side steam 31 cools the rotor blades and becomes high temperature, and is recovered from the four-stage disk 24 side to the axial recovery passage 18 through the radial recovery passage 17 in the turbine main shaft 1. . Therefore, as shown in FIG. 2B, the turbine main shaft 1 has a low temperature on the coupling surface 26 side and has a low temperature.
Is heated to a high temperature, a force acts as indicated by an arrow due to the thermal expansion, and acts to close the coupling surface 26 by receiving a force indicated by 1 '. Therefore, unlike the related art shown in FIG. 10, the coupling surface does not open due to thermal stress, and leakage of the supply-side steam can be prevented.

FIG. 3 is a sectional view taken along line AA in FIG.
The coupling surface 26 of the four-stage disk 24 is provided with a radial groove 40 which communicates with the supply passage 15 in the axial direction. A recovery passage 16 is provided between the supply passages 15 in the circumferential direction. The supply side steam 30 enters the groove 40 from the axial direction through the hole 41 at the center of the rotor, flows in the radial direction, enters the supply passage 15, is supplied to the rotor blades, and the cooled recovery side steam 31 passes through the recovery passage 16. The oil is recovered from the radial recovery passage 17 of the turbine main shaft 1 (not shown).

FIG. 4 is a detailed view of a portion B in FIG. 1. A cylindrical thermal shield 3 is mounted between the turbine main shaft 1 and the axial recovery passage 18 with a coupling bolt 7, and is connected to the turbine main shaft 1. A space 42 is kept between them. This space 42 forms a gas layer with steam or air, and heat generated by the high-temperature recovery-side steam 31 is
To the bearing 2 side.

FIG. 5 is a detailed view of a portion C in FIG. 1. A centering piece 6 is attached to the rear end side of the inner cylinder 10 and is connected to a cylindrical outer cylinder seal 5. The outer cylinder seal 5 is provided with a hole 5a, and the recovery-side steam 31 flows out of the hole, passes through a passage (not shown), is collected in a ground steam reservoir (header), and is reused in the plant. You.

Rotation-side seal fins 4b are provided on the inside of the stationary-side seal fins 4a and on the outside of the outer cylinder seal 5, respectively, to constitute stationary-side and rotation-side seals.
A part of the leakage steam 33a of the supply-side vapor 30 passes through the seal portion and flows out as a leakage steam 33b. However, since all of the leakage steam 33b flows into the passage 50 communicating with the above-mentioned ground vapor reservoir (header), Collected and used effectively.

FIG. 6 is a sectional view taken along the line DD in FIG. 1. The thermal shield 3 attached to the turbine main shaft 1 and the inner cylinder 10 form an axial recovery passage 18. A plurality of strut supports 8 are provided and supported between the thermal shield 3 and the inner cylinder 10.

FIG. 7 shows details of the portion E in FIG.
(A) is a detail of a cross-sectional view, and (b) is a view of the section taken along the line FF. In the figure, a groove is provided at the end of the inner cylinder 10, and a piston ring 43 is slidably provided at a joint between the groove and the turbine main shaft 1 in the circumferential direction. The connection portion of the radial collection passage 17 is sealed. Also, a number of struts 9 are provided in the inner end of the inner cylinder 10 in the circumferential direction so as to guide the supply steam 30 to the groove 40, and the inner center of the inner strut 9 has a middle strut as shown in FIG. An entity 44 is provided. On the other hand, even if the inner cylinder 10 is heated from the outside by the high-temperature recovery-side steam 31 and thermal expansion occurs, the piston ring 43 provided on the outer peripheral end of the cylinder 10 slides with the turbine main shaft 1 to be movable, Inner cylinder 1
It has a structure that absorbs 0 thermal expansion.

FIG. 8 shows details of the portion G in FIG. 1. A centering piece 6 is inserted between the outer cylinder seal 5 and the inner cylinder 10, and the flange 6a is provided at the front end with the outer cylinder seal 5 at its distal end.
And bolt 45. The inner cylinder 10 and the centering piece 6 are slidably engaged in the axial direction and function as a seal at the tip of the axial recovery passage 18. With such a structure, the thermal elongation can be absorbed even at the tip of the inner cylinder 10.

According to the steam-cooled gas turbine of the embodiment described above, an axial recovery passage 18 is provided inside the turbine main shaft 1 and an axial supply passage 19 is provided inside the turbine main shaft 1, so that the low-temperature supply side is provided. The steam 30 is supplied, and high-temperature steam is recovered in the axial recovery passage 18 outside the steam 30, so that leakage of the supply-side steam 30 to the outside is reduced. A groove 40 serving as a passage for the supply-side steam 30 is provided in the coupling surface 26 between the four-stage disk 24 and the turbine main shaft 1, and the supply passage 15 is provided.
The coupling surface 26
Act to close due to thermal stress. Further, a thermal shield 3 is provided in the bore of the turbine
A gas layer is provided therein to prevent high-temperature heat from the recovery-side steam 31 from being transmitted to the bearing 2 side, thereby preventing oil seizure.

Further, struts 8, 9 for supporting the inside of the axial recovery passage 18, a piston ring 43 at one end, and a centering piece 6 at the other end are provided to fix the inner cylinder 10 in the radial direction and to slide in the axial direction. It is made movable so that it can absorb thermal expansion, and the centering piece 6 facilitates assembly.

Further, with respect to the stationary side seal and the stationary side seal, the stationary side seal 4a and the rotating side seal 4b constitute a seal by fin processing, and the leakage steam 3 of the supply side steam 30 is formed.
Leakage steam can be effectively collected by allowing all of 3b to be collected in the ground steam reservoir.

[0044]

The steam-cooled gas turbine according to the present invention (1) has a plurality of steam supply passages in the main shaft for supplying steam in the axial direction from the rear end of the turbine main shaft, and steam from each of the steam supply passages in the main shaft. The in-disk steam supply passage, which is guided into the disk and supplied to the moving blade, and the in-disk steam recovery passage, which guides and recovers the steam that has cooled the moving blade, respectively, communicates with each of the in-disk steam recovery passage, A steam-cooled gas turbine having a steam recovery passage on the main shaft for collecting steam after cooling the rotor blades, wherein the steam supply passage on the main shaft passes through a center portion of the turbine main shaft, and the steam recovery passage on the main shaft is inside the main shaft. It is characterized by passing through the outer periphery of the steam supply passage. With such a configuration, the steam on the supply side passes through the center of the turbine main shaft and the recovery side is on the outside, so that leakage of the supply side steam to the outside can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of radial grooves are provided on a joint surface between the last stage of the disk and the turbine main shaft, and the radial steam supply passage and the main shaft are provided respectively. Connecting the internal steam supply passage with the internal steam supply passage, and providing a radial radial steam recovery passage on the turbine main shaft side behind the joint surface, and connecting the disk internal steam recovery passage and the main shaft internal steam recovery passage respectively. Features. With such a configuration, the steam recovery passage is on the downstream side of the joining surface between the disk and the turbine main shaft, so that high-temperature recovered steam flows on the rear side, and the joining surface between the disk and the turbine main shaft has a low temperature on the supply side. Of the steam. Therefore, the joint surface acts to close due to thermal deformation, thereby preventing the steam from leaking from the joint surface.

A third aspect of the present invention is characterized in that, in the first aspect of the present invention, a heat-sealing cylinder is provided on the outer inner peripheral wall surface of the steam recovery passage in the main shaft while maintaining a predetermined space. . With such a configuration, the outer inner peripheral wall surface of the steam recovery passage of the turbine main shaft maintains a predetermined space, and steam or air is sealed in this space to maintain a gas layer so that heat of the steam is transferred to the bearing side. Make it difficult to tell. As a result, seizure of oil can be prevented.

According to a fourth aspect of the present invention, in the first aspect of the present invention, a part of the in-spindle steam recovery passage is connected to a rear end of the in-spindle steam recovery passage, and a plurality of the plurality of steams are formed around the outer periphery. And a plurality of fins that cover the outer periphery of the rotating-side cylindrical seal member and have a seal portion on the inner peripheral surface facing the fin of the rotating-side cylindrical seal member. A stationary cylindrical seal member having
The rotary side cylindrical seal member and a centering cylindrical member for fixing a rear end of the steam supply passage in the main shaft are provided. According to such a configuration, a seal is formed by the cylindrical seal member on the rotating side and the cylindrical seal member on the stationary side, the seal is reliably performed, and the centering cylindrical member facilitates assembly.

According to a fifth aspect of the present invention, in the first aspect of the present invention, a supporting member is provided with a predetermined gap in a circumferential direction between the inner surface of the main steam recovery passage and the outer peripheral surface of the main steam supply passage. In addition, both ends of the steam supply passage in the main shaft are slidable in the axial direction. With such a configuration, axial elongation due to thermal deformation can be absorbed.

According to a sixth aspect of the present invention, in the first aspect of the present invention, a groove is provided around the outer periphery of the main shaft steam supply passage between the forward end portion of the main shaft steam supply passage and the turbine main shaft. The piston ring is inserted to prevent the steam on the supply side from leaking into the steam recovery passage in the main shaft. can do.

[Brief description of the drawings]

FIG. 1 is an overall sectional view of a steam-cooled gas turbine according to an embodiment of the present invention.

FIG. 2 shows details of a coupling surface between a turbine main shaft and a disk in FIG. 1, (a) is a detailed sectional view,
(B) is an explanatory view of the thermal deformation.

FIG. 3 is a view taken in the direction of arrows AA in FIG. 1;

FIG. 4 is a detailed sectional view of a portion B in FIG. 1;

FIG. 5 is a detailed sectional view of a portion C in FIG. 1;

FIG. 6 is a sectional view taken along line DD in FIG. 1;

FIGS. 7A and 7B show details of a portion E in FIG. 1, wherein FIG. 7A is a detailed cross-sectional view and FIG. 7B is a view taken along the line FF of FIG.

FIG. 8 is a detailed sectional view of a portion G in FIG. 1;

FIG. 9 is a sectional view showing an example of a four-stage disk portion of a conventional steam-cooled gas turbine.

10 is a view for explaining thermal deformation of a coupling surface between a disk and a bearing of the conventional steam-cooled gas turbine shown in FIG.

FIG. 11 is a sectional view showing another example of the conventional steam cooling system.

[Explanation of symbols]

 Reference Signs List 1 turbine main shaft 2 bearing 3 thermal shield 4a stationary seal fin 4b rotating seal fin 5 outer cylinder seal 6 centering piece 8, 9 strut support 10 inner cylinder 11a, 12a supply passage 11b, 12b recovery passage 11 one-step operation Blade 12 Two-stage bucket 15 Supply passage 16 Recovery passage 17 Radial recovery passage 18 Axial recovery passage 19 Axial supply passage 24 Four-stage disk 25 Fastening bolt 26 Coupling surface 27, 28, 29a, 29b Cavity 30 Supply side steam 31 Recovery-side steam 33a Supply-side leaked steam 33b Leaked steam 42 Space 44 Solid body

Claims (6)

[Claims] 1. A plurality of steam supply passages in the main shaft, which supply steam in the axial direction from the rear end of the turbine main shaft, and steam in the disk, which guides the steam into the disk from each of the steam supply passages in the main shaft and supplies the steam to the moving blade. A supply passage and a steam recovery passage in the disk for guiding and recovering the steam cooled in the rotor blade, and a steam recovery passage in the main shaft communicating with the steam recovery passage in the disk and recovering the steam after the blade cooling. A steam-cooled gas turbine having a passage, wherein the steam supply passage in the main shaft passes through a center portion of the turbine main shaft, and the steam recovery passage in the main shaft passes through the outer periphery of the steam supply passage in the main shaft. Cooling gas turbine. 2. A plurality of radial grooves are provided in a radial direction on a joint surface between the last stage of the disk and the turbine main shaft to connect the disk internal steam supply passage and the main shaft internal steam supply passage, respectively. 2. The steam-cooled turbine according to claim 1, wherein a radial radial steam recovery passage is provided on the turbine main shaft side behind the joining surface, and the disk-side steam recovery passage and the main shaft steam recovery passage are connected to each other. . 3. The steam-cooled gas turbine according to claim 1, wherein a heat-sealing cylinder is provided at a predetermined space on an outer inner peripheral wall surface of the steam recovery passage in the main shaft. 4. A part of the steam recovery passage in the main shaft, which is connected to a rear end of the steam recovery passage in the main shaft,
A rotating cylindrical seal member having a plurality of fins on the outer periphery, and a seal portion that covers the outer periphery of the rotating cylindrical seal member and has an inner peripheral surface facing the fins of the rotating cylindrical seal member. A stationary cylindrical seal member having a plurality of fins, and a centering cylindrical member for fixing a rear end portion of the rotary cylindrical seal member and the steam supply passage in the main shaft. Item 2. A steam-cooled gas turbine according to item 1. 5. A support member is provided between the inner surface of the steam recovery passage in the main shaft and the outer peripheral surface of the steam supply passage in the main shaft at a predetermined gap in a circumferential direction, and both ends of the steam supply passage in the main shaft are shafts. 2. The apparatus according to claim 1, which is slidable in any direction.
A steam cooled gas turbine as described. 6. A piston ring is inserted between the front end of the steam supply passage in the main shaft and the turbine main shaft, with a groove provided around the periphery of the steam supply passage in the main shaft. 2. The steam cooled gas turbine according to claim 1.