JP2981557B2 - Ceramic gas turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic gas turbine, and more particularly, to a combustion gas sealing structure.

[0002]

2. Description of the Related Art FIG. 2 shows a longitudinal section of a main part of a conventional metal gas turbine. A plurality of combustors 1 are installed on the circumference around the turbine shaft. The fuel and the combustion air compressed to a high pressure by the compressor 4 are supplied to the combustor 1,
It burns and generates high temperature, high pressure combustion gas. The combustion gas passes through a stationary blade stage 2 which is annularly installed on the downstream side of the combustor 1 via a gap, and is then guided to a moving blade stage 3 which is a movable portion, and the rotating blade stage 3 is annularly installed on the outer periphery. The rotating power is generated in the rotor 5 that has been rotated. In a large-capacity industrial gas turbine, the stationary blade stage 2 and the moving blade stage 3 are often installed in a plurality of pairs, and FIG. . The pressure and temperature of the combustion gas are highest in the first stage, and lower in the later stages. For this reason, in the following description, the combustor, the first stage stationary blade stage and the moving blade stage will be described, but the same applies to the second stage and three stage stationary blade stage and the moving blade stage. The elements constituting the combustion gas flow path through which the high-temperature combustion gas flows, that is, the combustor 1, the stationary blade stage 2, and the moving blade stage 3 are made of a heat-resistant alloy, and are cooled to a heat-resistant use temperature of the heat-resistant alloy by cooling air. Cooled.

In order to improve the thermal efficiency of a gas turbine, it is necessary to raise the temperature of combustion gas and reduce the amount of cooling air. In order to increase the temperature, it is considered effective to develop a heat-resistant superalloy with a high heat-resistant use temperature and to use structural ceramics with excellent high-temperature strength as members constituting the inner wall of the combustion gas flow passage. Turbine development is underway.

[0004] Although large-capacity ceramic gas turbines have not yet reached the practical stage, a technique using a part of ceramics, for example, a ceramic stationary vane stage is disclosed in Japanese Patent Application Laid-Open No. Sho 61/61.
-89909 and JP-A-61-89906. FIG. 3 shows a vertical cross section in the direction perpendicular to the axis of the ceramic stator blade stage. The stationary blade elements are radially arranged on the circumference, and the upper side in the figure corresponds to the outer peripheral side of the gas turbine, and the lower side corresponds to the inner peripheral side. The vane element comprises a ceramic wing body 9, walls 10 and 11 and a metal inner shroud 1 supporting them, which are directly exposed to the combustion gases.
4. It is composed of an outer shroud 15 and a shaft core 25,
Insulation members 12, 13 between the ceramic component and the metal component
Is interposed. After the cooling air cools the shaft core 25 as shown by the dotted arrow, the ceramic airfoil 9, the wall 10,
It flows out into the combustion gas passage formed by 11. on the other hand,
Inner shroud 14 and outer shroud 1 of adjacent vane elements
A metal seal plate 26 is inserted between the five to prevent the combustion gas from flowing out. Further, the structure of a conventional ceramic combustor is disclosed in Japanese Patent Application No. 1-51382, in which a ceramic component is disposed on an inner surface in contact with a combustion gas, and the ceramic component is supported by a metal component via a heat insulating member. This point is similar to that of the ceramic stationary blade. Further, as an example of a ceramic moving blade, the following document describes a ceramic moving blade in which a wing portion made of ceramic is fitted to a metal disk.

[0005] Reference "GRI Seminar on Application
s for and Designing with HighTemperature Material
s (April 6 and 7,1989) 1 to 40 '' As described above, gas turbines are installed between a plurality of combustors arranged circumferentially, Have gaps, and the combustion gas flows from those gaps as much as possible,
It is necessary to provide a seal structure so as not to leak. This is an important technique from the viewpoint of effectively utilizing the energy of the combustion gas and reducing the amount of cooling air by preventing the members outside the combustion gas passage from being heated by the leaked combustion gas.

FIG. 3 shows an example in which a combustion gas sealing structure implemented in a conventional metal gas turbine is applied to a ceramic gas turbine. Explaining the problem, in FIG. 3, the combustion gas flows from the gap between the adjacent wing bodies 9 as shown by the solid line arrows, from the inner metal shroud 14 and the outer metal shroud 1.
5. Since it flows out to the metal seal plate 26, its periphery is heated. For this reason, cooling of these metal members is required, and cooling air must be supplied from the shaft core 25 between the ceramic wing body 9 and the ceramic walls 10 and 11 as indicated by dotted arrows.

As described above, if the conventional seal structure of a metal gas turbine is applied to a ceramic gas turbine as it is, there is a problem that it is difficult to reduce the amount of cooling air.

[0008]

The prior art of a ceramic gas turbine using a ceramic member discloses only the basic structure of ceramic elements in each of a combustor, a stationary blade stage, and a moving blade stage. For example, in the conventional ceramic stator vane shown in FIG. 3, a seal structure of combustion gas between the stator vanes in the circumferential direction is disclosed, but between a combustor forming a combustion gas passage and a stator vane stage, No consideration is given to a seal structure for preventing combustion gas from flowing out from a gap provided between the stationary blade stage and the blade stage in consideration of thermal deformation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ceramic having a seal structure for reducing an amount of combustion gas leaking from a gap between a combustor and a first-stage vane stage, a gap between a vane stage and a moving blade stage, and a gap between adjacent combustors. It is to provide a gas turbine.

[0010]

In order to achieve the above object, a stationary blade stage and a moving blade stage are alternately arranged in a row with a gap therebetween, and a combustor is adjacent to the first stationary blade stage with a gap in between. Provided
At least the combustion gas passage of this combustor has a structure in which a ceramic inner wall member is provided inside a metal frame,
The blade body of the stationary blade stage and the blade stage and the inner wall surface of the combustion gas passage are formed by a ceramic member supported by a support member made of a metal member, and the support member is cooled by air. In the ceramic gas turbine, the gap between the ends of the combustion gas passages between the combustor and the first stationary blade stage, and the stationary ends of the combustion gas passages of the stationary blade stage and the moving blade stage. A seal member having elasticity and heat resistance is attached to each of the gap portions, and a gap portion between a combustion gas passage end of the stationary blade stage and a rotating end of the combustion gas passage of the rotor blade stage. A circumferential seal member is provided, one end of which is supported by one of the support members at the end of the combustion gas passage and the tip end of which is extended close to the other support member via a minute gap. Thus, a ceramic gas turbine was characterized.

[0011] On the opposite side of the combustion gas passage of the seal member attached to the gap between the combustion gas passages of the combustor and the first stationary vane stage, the seal member passes from the frame of the combustor to the support member of the vane stage. If a metallic sealing plate is provided, the sealing effect can be further enhanced. Alternatively, the metal sealing plate may be provided without mounting the sealing member.

Further, a seal member may be provided so as to extend between the end faces of the combustion gas passages of the adjacent combustors and to be pressed against the end faces.

Further, as a sealing member having elasticity and heat resistance, a ceramic fiber, a ceramic spring or a heat-resistant material having a spring effect is used as a mounting portion, and a structural ceramic or ceramic composite material is used as a seal body without air permeability. Insulating inorganic materials are preferred.

[0014]

According to the present invention, the above object is attained by the following operation according to the present invention. First, the gap between the combustor that forms the combustion gas passage and the stationary blade stage, and the stationary end between the stationary blade stage and the moving blade stage is sealed by installing an axial seal having elasticity and heat resistance, respectively. . Next, the gap between the stationary blade stage and the rotating blade stage rotating end is sealed by a circumferential seal member that is extended to approach through a minute gap. Further, the gap between adjacent combustors is sealed with a seal member having elasticity and heat resistance pressed against the end face.

The stationary ends of the combustor, the stationary blade stage and the moving blade stage to be subjected to the combustion gas seal thermally expand and contract due to a temperature difference between room temperature and a high temperature during operation, and the gap therebetween changes. Since the sealing member has elasticity and heat resistance, it can absorb the displacement of the sealing member, so that the sealing member can always perform a complete sealing function. Similarly, the axial gap between the stationary blade stage and the rotating blade stage rotating end also changes, but since the circumferential seal member is close to the small gap, the displacement caused by the temperature difference is absorbed and the sealing function is achieved. Can be kept.

Also, the gap between the combustors can cope with displacement because the heat-resistant non-permeable seal member is pressed toward the end.

As described above, leakage of the combustion gas from the combustion gas passage is sealed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a longitudinal sectional view of a first stage of a ceramic gas turbine having a seal structure according to an embodiment of the present invention. The upper side in the figure is the outer peripheral side of the ceramic gas turbine, and the lower side is the inner peripheral side. From the left side of the figure, the downstream end of the ceramic combustor 1 is shown, followed by the first ceramic stationary blade stage 2 and the ceramic moving blade stage 3. This configuration is the same as the conventional basic structure.

The ceramic combustor 1 has a structure in which a ceramic inner wall member 6 is held inside a metal frame 8 via a heat insulating member 7. The ceramic stationary blade stage 2 includes a ceramic blade body 9 serving as an inner wall surface of a combustion gas flow passage, a ceramic inner shroud 14 for holding a ceramic member via heat insulating members 12 and 13 and ceramic shrouds 15, and an outer shroud 15. Consists of The ceramic blade stage 3 has a ceramic blade 16 fitted on a metal disk 17, and two metal fixing plates 18 fixed to the disk 17 by metal rivets 19. In addition, ceramic bucket stage 3
A blade shroud 20 made of a heat-resistant material is provided on the outer periphery of the blade. The combustion gas flows in the combustion gas passage as indicated by the solid arrow.

The above-mentioned ceramic stationary vane stage 2 as a stationary element
And an axial seal 21 between the ceramic combustor 1 and the blade shroud 20 for preventing the outflow of combustion gas in the radial direction. The axial seal 21 is capable of deforming or moving in response to a change in dimensions between adjacent elements due to temperature changes between room temperature and high temperatures during operation of the ceramic gas turbine. It is pressed so that there is no gap between the elements.
FIG. 4 shows a partial longitudinal sectional view of the ceramic vane stage 2 provided with the axial seal 21. The axial seal 21 is attached to an end of the stationary blade heat insulating member 13 between the ceramic wall 11 and the outer metal shroud 15 by a mounting portion 27 made of an inorganic material having excellent heat resistance and elastic deformation, for example, a ceramic fiber or a ceramic spring. And heat-resistant, non-breathable inorganic material,
For example, the sealing member 28 is made of a structural ceramic or a ceramic composite material. Although not shown, a passage may be provided in the seal body 28 to serve as a cooling air exhaust hole for the ceramic stationary blade.

Although a plurality of the ceramic combustors 1 shown in FIG. 1 are installed on the circumference, they are held without any gap between the adjacent ceramic combustors 1 and the end face of the ceramic combustor, and are arranged in the axial direction. Is provided with a circumferential seal 23 for preventing the combustion gas from flowing out. A cross-sectional view of the circumferential seal 23 is shown in FIG. The mounting portion 29 held in the groove provided in the metal frame 8 of the ceramic combustor 1 has a spring effect and may also serve as a seal for combustion air. The sealing member 30 made of an inorganic material having heat resistance and non-permeability, for example, a structural ceramic or a ceramic composite material is attached to the mounting portion 2.
9 presses against the end face of the combustion gas passage of the ceramic combustor 1 and is held without any gap. That is, according to the axial and circumferential seal structures 21 and 23 according to the present invention, the combustor metal frame 8, the metal inner shroud 14, and the metal outer shroud 15 having low heat resistance due to the leakage of the combustion gas.
Etc. can be reduced.

Further, as shown in FIG. 1, a metal sealing plate 22 is provided between the grooves provided on the outer periphery of the combustor metal frame 8 and the grooves provided at the ends of the inner metal shroud 14 and the outer metal shroud 15. Since it is installed to prevent combustion air from flowing into the combustion gas passage, the axial seal 21
Therefore, even when a failure occurs, the ceramic component is prevented from being cooled, and a large thermal stress is generated in the ceramic component, thereby preventing the ceramic component from being broken.

Next, the ceramic moving blade stage 3 as a rotating element
6 shows details of an example of the inner peripheral side seal. FIG. 6 is a partial vertical sectional view of the inner peripheral side seal of the ceramic bucket stage, and the lower side of the figure is the inner peripheral side. The circumferential seal member 24 is provided on the stationary plate 18 at the blade stage, and the tip thereof is close to the metal shroud 14 via a small gap. In the metal shroud 14 of the ceramic vane stage 2, a cooling air exhaust hole 31 is provided at a position on the side closer to the combustion gas flow path than the circumferential seal member 24. Further, since high-pressure air for sealing is supplied to the inner peripheral side of the circumferential seal member 24, the seal air and the cooling air flow into the combustion gas passage from the minute gap at the tip of the circumferential seal member 24. It flows out as shown by the broken line. This prevents the combustion gas from flowing into the gap between the ceramic vane stage 2 and the ceramic bucket stage 3 as shown by a solid line and heating the metal shroud 14 or the fixed plate 18. Further, since the cooling air exhaust hole 31 provided in the inner metal shroud 14 is provided on the inner peripheral side of the circumferential sealing member 24, the pressure in the combustion gas passage is rapidly decreased due to rapid shutoff of the gas turbine fuel. Even in an emergency, the change in the flow rate of cooling air, which is determined by the difference between the supply pressure of the cooling air and the pressure loss of the exhaust port, is gradual, reducing the risk of quenching the ceramic parts and causing a thermal shock to cause damage, and improving reliability. There is.

FIG. 4 shows an example in which the mounting portion 27 of the axial seal 21 is provided in the ceramic stationary blade stage 2. However, the same effect can be obtained by providing the ceramic combustor 1 or the moving blade metal shroud 20. Can be The same applies to a conventional metal gas combustor, a stationary blade stage, a moving blade stage, and a combination ceramic gas turbine in which some of them are made of ceramic. FIG. 7 shows an axial seal 2 in a conventional metal combustor.
1 is shown. The figure is a partial vertical cross-sectional view of the downstream end of the combustor, and includes an attachment portion 27 and a deformed portion 28 on the outer periphery of the combustor metal frame 8 as in the embodiment shown in FIG. Further, although the circumferential seal 23 shown in FIG. 5 is an example provided in the ceramic combustor 1, the same effect can be obtained by using a conventional metal combustor.

FIG. 8 is a cross-sectional view of another embodiment of the circumferential seal 23 shown in FIG. 5, in which the seal portion has an inner layer 32 made of an inorganic material having high heat resistance and toughness, for example, a ceramic composite material. It is made of an inorganic material having high heat resistance and no air permeability, for example, two kinds of materials of an outer layer made of the structural ceramics 33. Inner layer 32 incorporating mounting portion 29
Since it is rich in toughness, there is little risk of breakage even when an external force is applied, and reliability can be improved. Inner layer 32 and outer layer 33
Can be manufactured by integral molding or joining. Also, as shown in FIG. 9, the joint reliability can be improved by additionally providing a fitting structure to the inner and outer layers 32 and 33. Further, FIG.
As shown in FIG. 0, the mounting portion 29 and the seal body 30 may be fitted and mounted.

FIG. 11 shows another embodiment of the inner peripheral side seal structure of the ceramic bucket stage 3. The inner metal shroud 14 is located closer to the anti-combustion gas flow path than the minute gap at the tip of the circumferential seal member 24 of the ceramic bucket stage 3. For this reason, the shroud 14 in the metal is not directly heated by the combustion gas, which is effective in reducing the amount of cooling air in the ceramic stationary vane stage 3.

FIG. 12 is a longitudinal sectional view of a first stage portion of a turbine showing another embodiment. According to this sealing structure, the cooling air and the sealing air are supplied between the combustor heat insulating member 7 and the combustor metal frame 8, the vane heat insulating member 12 and the metal shroud 1.
During 4, by discharging into the combustion gas passage from between the stationary blade heat insulating member 13 and the outer metal shroud 15, it is possible to mitigate that the combustion gas enters the metal member and heats it. In this case, the seal shown in FIG. 6 may be applied to the inner peripheral side seal of the ceramic bucket stage 3.

[0029]

As described above, according to the present invention,
Since the seal structure capable of reducing the amount of the combustion gas flowing out is provided, the heating of the metal member supporting the ceramic member is eased, and the amount of cooling air can be significantly reduced as compared with the conventional metal gas turbine. If the amount of cooling air can be reduced,
Further, a decrease in the temperature of the combustion gas due to the inflow of the cooling air can be mitigated. As a result, there is an effect of improving the thermal efficiency of the ceramic gas turbine.

Further, since the amount of cooling air is reduced, a large temperature distribution generated by cooling the ceramic member, that is, the generation of thermal stress is reduced, and there is an effect of improving the reliability of the ceramic gas turbine.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a first stage of a ceramic gas turbine according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a conventional metal gas turbine.

FIG. 3 is a vertical cross-sectional view in a direction perpendicular to an axis of a conventional ceramic vane stage.

FIG. 4 is a partial longitudinal sectional view of a ceramic vane having an axial sealing structure according to an embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a ceramic combustor having a circumferential seal structure according to one embodiment of the present invention.

FIG. 6 is a partial longitudinal sectional view of a ceramic rotor blade stage inner peripheral side seal structure according to an embodiment of the present invention.

FIG. 7 is a partial longitudinal sectional view of a conventional axial seal structure of a combustor.

FIG. 8 is a partial cross-sectional view of a ceramic combustor having a circumferential seal structure according to another embodiment of the present invention.

FIG. 9 is a partial cross-sectional view showing the detailed structure of FIG. 8;

FIG. 10 is a cross-sectional view of a circumferential seal structure according to another embodiment of the present invention.

FIG. 11 is a partial longitudinal sectional view of a ceramic rotor blade stage inner peripheral side seal structure according to another embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of a first stage of a ceramic gas turbine according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic combustor 2 Ceramic stationary blade stage 3 Ceramic moving blade stage 4 Compressor 5 Rotor 6 Combustor ceramic inner wall 7 Combustor heat insulating member 8 Combustor metal frame 9 Ceramic wing body 10 Ceramic wall 11 Ceramic wall 12 Static blade insulating member 13 Stator blade heat insulating member 14 Metal shroud 15 Metal outer shroud 16 Ceramic blade 18 Fixed plate 20 Moving blade metal shroud 21 Axial seal 22 Seal plate 23 Circumferential seal 24 Circumferential seal member 25 Shaft core 27 Mounting part 28 Seal body 29 Mounting part 30 Seal body 31 Cooling air exhaust hole 32 Inner layer 33 Outer layer 34 Combustion gas flow 35 Cooling air flow

──────────────────────────────────────────────────続 き Continuation of the front page (72) Isao Yuri, Inventor 11-27, Hagino, Yokosuka City, Kanagawa Prefecture Denken Matsuyama Dormitory (56) References JP-A-3-213601 (JP, A) JP-A-2-233908 (JP) JP-A-61-89906 (JP, A) JP-A-53-37221 (JP, A) JP-A-1-125502 (JP, A) JP-A-57-41406 (JP, A) 61-89909 (JP, A) JP-A-2-55839 (JP, A) JP-A-54-27611 (JP, A) JP-A-60-30431 (JP, A) JP-A-60-88002 (JP, A) U) Shokai Sho 62-176448 (JP, U) Shokai Sho 62-87132 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02C 7/28 F01D 5/28 F01D 9 / 02 102 F01D 11/00

Claims (6)

(57) [Claims] 1. A stator blade stage and a rotor blade stage are alternately arranged with a gap therebetween, and a combustor is provided adjacent to the first stator blade stage with a gap therebetween, and at least a combustion gas passage of the combustor is provided. The flow path has a structure in which a ceramic inner wall member is provided inside a metallic frame, and the vanes of the stationary blade stage and the moving blade stage and the inner wall surface of the combustion gas passage are supported by a support member made of a metal member. In a ceramic gas turbine formed by a ceramic member formed and cooled by air, a gap portion at an end of a combustion gas passage between the combustor and the first stationary vane stage, A seal member having elasticity and heat resistance is attached to a gap between the stationary blade stage and the stationary end of the combustion gas passage of the rotor blade stage, respectively. Between the section and the rotating end of the combustion gas passage of the bucket stage A circumferential seal member is provided in the gap, one end of which is supported by one of the support members at the end of the combustion gas passage, and the distal end of which is extended close to the other support member via a minute gap. A ceramic gas turbine. 2. The combustor according to claim 1, wherein a seal member mounted in a gap between the combustion gas flow passage walls of the combustor and the first stationary blade stage has a combustion gas flow passage opposite to the combustion gas flow passage. A ceramic gas turbine, wherein a metal seal plate is provided from the frame to the support member of the stationary blade stage. 3. The stationary vane stage according to claim 1, wherein the stationary vane stage is constituted by a plurality of stationary vane elements, each stationary vane element being fixed to a metallic inner shroud fixed to the inner peripheral side of the turbine and to an outer peripheral side. Metal outer shroud, a ceramic wall member attached to the opposing surfaces of the inner shroud and the outer shroud via a heat insulating material, and sandwiched between the outer shroud and the inner shroud via the ceramic wall member A hollow ceramic wing body, and a shaft core that is inserted into the hollow portion of the ceramic wing body between the outer shroud and the inner shroud, applies a clamping force to the ceramic wing body, and supplies cooling air to the hollow portion. Wherein the circumferential seal member is supported by a rotating end of a moving blade stage, and a tip end extends close to the inner shroud of a stationary blade stage via a minute gap, A cooling air exhaust hole having an open end located on the opposite side of the combustion gas flow path at the tip of the circumferential seal member in communication with the hollow portion of the suction wing body. Characteristic ceramic gas turbine. 4. The sealing member according to claim 1, wherein the elastic and heat-resistant sealing member includes a mounting portion formed of ceramic fiber, a ceramic spring or a heat-resistant material having a spring effect, and a structural ceramic or ceramic composite material. A ceramic gas turbine comprising a seal member formed of an inorganic material having heat resistance and heat insulation without air permeability. 5. The seal member according to claim 1, wherein a plurality of the combustors are provided in a circumferential direction of the turbine, and the sealers are arranged to pass over the end faces of the combustion gas passages of adjacent combustors and to be pressed against the end faces. A ceramic gas turbine characterized by being provided. 6. A stationary blade stage and a moving blade stage are alternately arranged with a gap therebetween, and a combustor is provided adjacent to the first stationary blade stage with a gap therebetween, and at least a combustion gas flow of the combustor is provided. The flow path has a structure in which a ceramic inner wall member is provided inside a metallic frame, and the vanes of the stationary blade stage and the moving blade stage and the inner wall surface of the combustion gas passage are supported by a support member made of a metal member. In a ceramic gas turbine formed of a ceramic member formed and cooled by air, the supporting member is provided in a gap at an end of a combustion gas passage between the combustor and the first stationary vane stage. A metallic sealing plate is provided from the combustor frame to the stationary blade stage support member, and a combustion gas passage end of the stationary blade stage and a rotating end of a combustion gas passage of the rotor blade stage are provided. One end of one of the combustion gas flows through the gap A ceramic gas turbine provided with a circumferential seal member supported by a support member at a road end and having a front end portion extending close to the other support member via a minute gap.