JPH04203302A - Ceramic stationary blade - Google Patents

Abstract

PURPOSE:To reduce a quantity of heat invading into a metal parts and decrease a quantity of cooling air by providing a seal means against combustion gas on an opposite wall portion between mutually adjacent unit stationary blades among ceramic stationary blades for a gas turbine. CONSTITUTION:The cross sectional shape of a seal plate 17 corresponds to the cutting-out shape of the edge surface of outside walls 3, 3'. The seal plate 17 is installed between the mutually adjacent outside walls 3, 3', fills up a space in the circumferential direction, and eliminates a bypass stream caused by a radial flow of combustion gas. A seal plate 18 is installed between mutually adjacent outer heat insulators 9, 9' and outer shrouds 5, 5', so as to block voids in the combustion gas stream flowing in the axial direction, and eliminates any bypass stream caused by the combustion gas which flows out from an upstream side edge surface of stationary blade rows into gaps between the outer side walls 3, 3' and the outer shrouds 5, 5'. A seal plate 19 is provided between the mutually adjacent outer shrouds 5, 5' so as to block voids in the circumferential direction, and eliminates flowing-in of cooling air which is supplied to the outside of the outer shrouds 5, 5' into a combustion gas passage. Subsequently, a quantity of heat flowing in a metal parts can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic stator blade in a gas turbine, and particularly to a ceramic stator blade having a structure suitable for improving performance and reliability.

[Conventional technology]

Conventional metal stationary blades for gas turbines use air to cool the inner walls and surfaces of the blades, keeping the true temperature below the heat-resistant temperature of the material. Ceramic stator vanes using ceramics with high heat resistance are considered to be effective in improving the efficiency of gas turbines because they require less cooling air, and development is progressing. Conventional ceramic stator vanes for industrial large-capacity gas turbines have not yet reached the practical stage, but for example, Japanese Patent Application Laid-Open No. 61-89905, Transactions of the Japan Society of Mechanical Engineers 54-
505A, (Showa 63-9) 1700 and the 18th Gas Turbine Regular Conference Lecture Proceedings (90-6) 153. FIG. 2 shows a schematic vertical cross-sectional view of a conventional ceramic stator vane. The upper side of the figure is the outer peripheral side of the gas turbine.
The lower side also corresponds to the inner peripheral side. Ceramic parts directly exposed to combustion gases (ceramic shell 1, inner and outer ceramic sidewalls 2, 3) and metal parts (inner and outer shrouds 4, 5) supporting the ceramic parts via heat insulating members 7, 8.9. , a wing core 6). In this way, ceramic stator blades have a composite structure of ceramic and metal parts. Further, in order to hold the ceramic parts with a uniform load, the heat insulating members 7, 8, 9 are made of a material that has a buffering function and is rich in deformability.

[Problem to be solved by the invention]

The above-mentioned prior art discloses the basic structure of a ceramic stator blade, but does not give consideration to the sealing of cooling air and combustion gas between adjacent blades when forming a row of stator blades.

In conventional metal stator vanes, cooling air and combustion gas were sealed in the shroud that formed the outer peripheral wall of the combustion gas flow path. Consider the case where sealing is performed using the inner and outer shrouds 4 and 5, which are made of metal, similar to the case with the stator vanes.

Fig. 3 is an external view of a part of the blade row of ceramic stator blades formed by arranging the unit stator blades in an annular shape, as seen from the upstream side of the combustion gas, and Fig. 4 is a cross-sectional view taken along the line A-A in Fig. 3. Show the diagram. A gap X is provided between adjacent unit stationary blades in consideration of thermal expansion deformation. High-temperature combustion gas flows into the inner and outer shrouds 4 and 5 through the interblade gap X of the blade row. Also,
Ceramic woven cloth or the like is suitable as the heat insulating members 8 and 9, which have excellent heat resistance and deformability, but combustion gas enters a wide range through the heat insulating members 8 and 9 because of their breathability.

In this way, an increase in the bypass flow that flows outside the original combustion gas flow path causes a decrease in the fluid efficiency in the stator vanes, as well as an increase in the amount of air required to cool the metal inner and outer shrouds 4 and 5. leading to an increase in That is, there was a problem that the efficiency of the gas turbine decreased.

An object of the present invention is to solve the above-mentioned problems and provide a ceramic stator blade with excellent performance and reliability.

[Means to solve the problem]

In order to achieve the above object, the ceramic stator vane of the present invention has a structure that appropriately seals combustion gas and cooling air when a blade row is formed. That is, in a ceramic stator vane consisting of a ceramic component that forms a combustion gas flow path and is directly exposed to high-temperature combustion gas, and a metal component that holds the ceramic component via a heat insulating member, the combustion gas seal is formed by the ceramic component, Alternatively, it is characterized in that it is done in the heat insulating member part, and the cooling air is sealed in the metal part part. In addition, the heat insulating member has excellent heat resistance and has a multilayer structure consisting of a non-porous heat insulating plate and a highly deformable cushioning material, which improves the sealing effect of combustion gas in the part of the heat insulating plate. It is a feature.

(Function) Since the high-temperature combustion gases are sealed using ceramic parts with excellent heat resistance or non-ventilated insulation materials, metal parts with relatively low heat resistance are heated by the intrusion of combustion gases. Therefore, the amount of cooling air can be significantly reduced compared to conventional metal vanes.

Furthermore, since the cooling air is sealed at the metal parts, it is possible to prevent the ceramic parts from being cooled and causing a large temperature distribution, that is, thermal stress. In addition, since the heat insulating member has a multilayer structure including a buffer material with high deformability, it is possible to prevent the occurrence of local stress due to uneven contact of the heat insulating material and, by extension, the ceramic component. Therefore, damage to the ceramic component or the heat insulating member can be prevented.

Due to the above effects, the present invention can improve the reliability of ceramic stator vanes and the efficiency of gas turbines.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical cross-sectional view showing the basic structure of one ceramic stator blade, that is, a unit stator blade, constituting the gas turbine stator blade cascade shown in FIG. The side is the same inner circumferential side. The illustrated ceramic stator vanes are fitted and held by a metal outer shroud 5 that is fitted and fixed to a retainer ring (not shown), and a support ring (also not shown) that is disposed opposite to the outer shroud 5. an inner shroud 4 , an inner heat insulating plate 8 that is fitted into a stepped portion formed on a surface of the inner shroud 4 facing the outer shroud 5 and overlapped with each other; an outer heat insulating board 9 which is fitted into and overlapped with a stepped portion formed on a surface of the inner ceramic side wall 2 which is superimposed on a surface of the inner heat insulating board 8 that faces the outer heat insulating board 9; The outer ceramic side wall 3 overlaps the surface of the outer heat insulating board 9 facing the inner heat insulating board 8, and the stepped portions formed on the mutually opposing faces of the inner and outer ceramic side walls 2 and 3 have both ends. are fitted and sandwiched between the inner and outer ceramic side walls 2 and 3. A ceramic shell 1 having an airfoil-shaped cross section is integrally formed so as to protrude from the surface of the metal outer shroud 5 on the side where the stepped portion is formed,
A metal wing core 6 that passes through the inner and outer heat insulating plates 8, 9, the inner and outer ceramic sidewalls 2, 3, and the ceramic shell 1 and is connected to the inner shroud 4;
and a heat insulating member 7 interposed between the ceramic shell 1, and between the inner heat insulating board 8 and the inner shroud 4 and between the outer heat insulating board 9 and the outer shroud 5, respectively. The cushioning material 10, which is highly deformable and has excellent heat resistance, is attached in a compressed and deformed state. Cooling gas flow paths 11, 12, 13, 14.degree. 15 are formed in the blade core 6, the inner and outer heat insulating plates 8, 9, and the inner and outer shrouds 4.5.

The combustion gas flow path is formed by the inner and outer ceramic side walls 2゜3, which form cylindrical wall surfaces on the inner and outer peripheries, and the ceramic shell 1, and the high-pressure combustion gas flows through the combustion gas flow path. While flowing in the direction of the arrow in the figure, the pressure decreases, the flow velocity increases, etc., and the fluid is guided to a rotor blade (not shown) provided downstream. Although each of the above-mentioned ceramic parts is subjected to an external force due to a pressure difference, the ceramic parts are supported by the blade core 6 and the inner and outer shrouds 4 and 5, which are metal parts, and no large stress is generated in the ceramic parts due to the external force.

Also, the inner and outer shrouds 4, 5 are fixed to the casing in the same manner as before. Furthermore, even when the amount of radial thermal expansion caused by heating by combustion gas differs between each member and the blade core 6, the difference is automatically adjusted by deformation of the buffer material 10, and the difference between each member is They are held tightly together without any gaps or excessive compressive force. In other words, this ceramic stator blade has a basic structure with high strength and reliability.

Next, a method for cooling metal parts will be explained. The ceramic stator blade shown in FIG. 1 is an example intended for a first stage stator blade of a gas turbine. From the outer periphery of the outer shroud 5 to the perforated plate 16
The cooling air that has flowed in through the outer shroud 5 impinges on the outer circumferential wall of the outer shroud 5 and cools the outer circumferential wall. A part of the cooling air then passes through a flow path 12 provided inside the blade core 6 to cool the blade core 6, and then passes through a flow path 1 provided on the outer periphery of the blade core 6.
3 to further cool the blade core 6. The gas then flows out into the combustion gas flow path after passing through the flow path 14 provided in the inner and outer heat insulating plates 8 and 9. Note that the position of the flow path 14 is not limited to the illustrated position, but may be any position that is away from the ceramic sidewall, for example, between the inner and outer shrouds 4 and 5 where the breathable cushioning material 10 is installed, and the inner and outer shrouds 4 and 5. The flow path 13 may also be extended between the outer heat insulating plates 8 and 9. The remaining cooling air flows through a flow path 15 provided inside the outer shroud 5.
After cooling the outer shroud 5, it flows out into the combustion gas flow path. The effect of the cooling air introduced from the inner periphery of the inner shroud 4 is similar to that of the cooling air of the outer shroud 5 described above.

On the other hand, the blade core 6 and the inner and outer shrouds 4, which are metal parts,
The amount of heat flowing into the housing 5 is blocked by the heat insulating member 7 or the inner and outer heat insulating plates 8 and 9 and the buffer material 1o. Furthermore, to reduce the amount of heat flowing in, a seal structure was provided between adjacent blades in the blade row. FIG. 5 is an external view of the seal structure on the outer peripheral wall as seen from the upstream side of the combustion gas flow. Figure 6(a) shows the fifth
B-B sectional arrow view in the figure, FIG. 6(b) is the same
The seal plate 17 shown in the cross-sectional view of B' corresponds to the shape of the notch provided in the end face of the outer side walls 3, 3', and has a cross-sectional shape corresponding to the shape of the notch provided in the end face of the outer side walls 3, 3'. It is installed to close the gap in the circumferential direction. Therefore, the combustion gas does not flow out of the gas flow path in the radial direction to create a bypass flow.

Although the embodiment has shown a triangular cross-sectional shape, it may also have a rectangular shape, a fan shape, or the like.

The seal plate 18 is installed between the adjacent external heat insulating materials 9,9' and the outer shrouds 5, 5' to close the gap in the axial direction of the combustion gas flow. Further, the outer heat insulating plates 9, 9' have no air permeability. Therefore, combustion gas flows from the upstream end face of the stator blade row to the outer sidewall 3.3' and the outer shroud 5, 5'.
There will be no leakage between them and a bypass flow. If the seal plate 18 is additionally installed at the downstream end and between the upstream end and the downstream end (not shown), the effect of preventing the bypass flow of the burning gas can be increased.

The seal plate 19 then seals the adjacent outer shroud 5.5'
It is installed in between to close the gap in the circumferential direction. For this reason, although the seal structure on the outer circumference side has been described above, where the cooling air supplied to the outside of the outer shrouds 5, 5' does not flow into the combustion gas flow path, the seal structure on the inner circumference side has also been described. The same is true.

The heat shielding structure and sealing structure described above greatly reduce the amount of heat flowing into metal parts, so compared to conventional metal blades, the amount of heat flowing into metal parts is significantly reduced.
The required low temperature is maintained by the amount of cooling air of /1o. Furthermore, since bypass flow is prevented, the fluid performance of the stationary blades does not deteriorate.

As a result, the present ceramic stator vane has the effect of improving the efficiency of a gas turbine. Furthermore, since the cooling air is prevented from flowing into the combustion gas flow path, the ceramic component is not cooled and damaged due to large temperature distribution, that is, thermal stress. As a result, the reliability of the ceramic stator blade can be improved.

The shell 1 and the outer sidewalls 2 and 3, which are directly exposed to high-temperature combustion gas, are made of structural ceramics with excellent heat resistance. The inner and outer heat insulating plates 8 and 9 are made of an inorganic material with excellent heat resistance and heat insulation properties and no air permeability, such as fiber-reinforced ceramics. This is because the heat insulating member 7 is required to have excellent heat resistance and heat insulation properties, and to be able to fill a narrow gap.

Manufactured using an inorganic filler, such as an alumina filler. Note that if a double structure is provided in which a buffer material, which will be described later, is provided at the boundary with the blade core 6, the air cooling effect of the blade core 6 will be improved. The highly deformable cushioning material 10 needs to have excellent elastic deformability as well as heat resistance, and is manufactured from a fabric made of a flexible inorganic material, such as ceramic fiber. Seal plate 17.
Reference numeral 18 is made of a non-breathable, heat-resistant inorganic material such as structural ceramics, fiber-reinforced ceramics, heat insulating material, etc., and the seal plate 19 is made of a heat-resistant metal for the blade core 6 and inner and outer shrouds. 4 and 5 are manufactured from a heat-resistant alloy, but compared to conventional metal stator blades, a popular grade with a lower heat resistance, such as stainless steel, can be used, and manufacturing is easy.

Another embodiment of the ceramic stator vane will be described with reference to FIG.

FIG. 7 corresponds to the upper half of FIG. 1.

The lower half is omitted because it is similar to FIG. 1. The inner shroud 4 (omitted) and the blade core 6 are integrally formed, and after the blade core 6 is fitted with the outer shroud 5, it is connected to a nut via a perforated plate 16 and a spring 20 provided on the outside of the outer shroud 5. 21, and the parts between the inner and outer shrouds 4, 5 are held in close contact by compressive force. The difference in thermal expansion between the blade core 6 and the parts between the inner and outer shrouds 4 and 5 is adjusted by elastic deformation of the spring 20. Therefore, the cushioning material is omitted in this embodiment. Incidentally, by installing the cushioning material 10 between the parts as in FIG. 1, a uniform compressive force can be obtained. Furthermore, the seal structure is the same as in the previous embodiment.

FIG. 8 is a cross-sectional view in the direction of the arrows corresponding to FIG. 6.

The second embodiment shown in FIG. 7 is another embodiment in which the combination structure of the outer shroud 5 and the outer heat insulating board 9 is different. The outer shroud 5 and the outer heat insulating board 9 have a structure in which they are stacked one on top of the other without intervening a cushioning material, and are easy to manufacture because of their simple shape without a fitting part. The seal structure is the same as in the first embodiment.

〔Effect of the invention〕

According to the present invention, in a ceramic stator vane in which a ceramic part is held by a metal part via a heat insulating member, the amount of heat penetrating into the metal part can be reduced, so the amount of cooling air is significantly reduced compared to conventional metal blades. I can do it. Furthermore, since bypass flow of combustion gas can be prevented, fluid performance can be improved compared to conventional ceramic stator vanes. As a result, there is an effect of improving the efficiency of the gas turbine. Furthermore, damage to ceramic parts or heat insulating members is prevented, and the reliability of ceramic stator blades is improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view showing the first embodiment of the present invention, and FIG.
The figure is a schematic vertical cross-sectional view of a conventional stator blade, Figure 3 is an external perspective view showing a part of a stator blade row, Figure 4 is a cross-sectional view taken along line A-A in Figure 3, and Figure 5 is the invention according to the present invention. An external perspective view of a part of the blade row showing the seal structure of the first embodiment, FIG. FIG. 7 is a schematic vertical cross-sectional view showing a second embodiment of the present invention, and FIG. 8 is a cross-sectional view in the direction of arrows showing a third embodiment of the present invention. 1... Ceramic parts (ceramic shell), 2.3
... Ceramic parts (inner and outer ceramic side walls), 4.5... Inner and outer shrouds, 6... Wing core,
7... Heat insulation member, 8, 9... Inner and outer heat insulation board, 10.
...Cushioning material, 17,18.19...Seal plate.

Claims (1)

[Scope of Claims] 1. In a ceramic stator vane for a gas turbine in which unit stator vanes are arranged in an annular manner, in which a ceramic member forming a combustion gas flow path is held by a metal member via a heat insulating member, adjacent unit stator vanes are A ceramic stationary vane characterized in that a sealing means against combustion gas is provided on the opposing wall between the vanes. 2. In claim 1, the sealing means includes a first seal that prevents combustion gas flowing in the radial direction through the gap between adjacent unit stator blades from flowing toward the metal member, and a second seal that prevents combustion gases flowing axially through the gap from flowing toward the insulation member. 3. The ceramic stator vane according to claim 1 or 2, wherein the sealing means is made of an inorganic material such as non-porous heat-resistant structural ceramics or fiber-reinforced ceramics. 4. In any one of claims 1 to 3, the heat insulating member provided at both ends of the blade core is made of ceramic comprising a heat insulating member with poor air permeability and low deformability and a shock absorbing material with high deformability and heat resistance. Static wings. 5. The ceramic stationary blade according to claim 4, wherein instead of the buffer material, urging means for fastening the blade core to the metal member is provided. 6. A ceramic stator vane according to any one of claims 1 to 5, further comprising an air sealing means for preventing cooling air from flowing toward the ceramic member through the gap between adjacent unit stator vanes.