JPS59185804A - Gas turbine - Google Patents

Abstract

PURPOSE:To absorb thermal expansion and shrinkage by fixing the inner peripheral end of a stator blade made of ceramic to an inner side support ring through a heat insulating member which is in surface contact with said end and also fixing the outer peripheral end to the outside support ring through a heat insulating member in surface contact with said end and a plate spring. CONSTITUTION:The inner peripheral end of a turbine stator blade 8 made of ceramic material is fixed to an inner side support ring 22 through a heat insulating member 21 which is in surface contact with said end, while the outer peripheral end of said blade is fixed to an outside support ring 12 through a heat insulating member 35 in surface contact with said end and a plate spring 36. Since the stator blade 8 is supported in a manner as abovementioned, even if the blade is expanded or shrunk in the directions of the depth and the height due to change of the temperature, both can be absorbed by elastic operation of the plate spring 36 and sliding surface operation of the surface contact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas turbine, and more particularly to a gas turbine in which the supporting structure of the stator vane is improved in a turbine whose blades are formed of a ceramic material.

[Background technology of the invention and its problems]

A gas turbine usually has a compressor and a turbine connected to one shaft, uses high-pressure air compressed by the compressor to increase the pressure in the combustor, and in this state fuel is injected into the combustor to perform combustion. The high-temperature, high-pressure gas produced by this combustion is guided to a turbine and expanded, thereby generating rotary power. A compressor is constructed by alternately arranging guide vanes and rotor blades in the axial direction, and a turbine is also constructed by arranging stator vanes and rotor blades alternately in the axial direction.

By the way, in the above gas turbine, it is said that the most effective way to increase the output efficiency is to increase the temperature of the combustion gas at the inlet of the turbine. However, the inlet gas temperature of the turbine is limited by the heat resistance strength or high-temperature oxidation/corrosion characteristics of the materials constituting the turbine blades. Therefore, a method is usually adopted in which the temperature of the turbine inlet gas is increased by forcibly cooling the blades with a cooling fluid.

However, with the method of forcedly cooling the blades with cooling fluid, while it is possible to suppress the temperature rise of the blades to some extent, on the other hand, since the blades are forcedly cooled, it is possible to avoid a drop in gas temperature. There was a problem in that the effect of increasing the inlet gas temperature was not so great.

Recently, in order to eliminate the above-mentioned problems, turbine blades are made of high-temperature, high-strength materials, such as Si.
Attempts have been made to use ceramics such as 3N4. The above-mentioned ceramic material is stable even at a temperature of about 1400° C., and its mechanical strength does not decrease. Therefore, unlike the case where the blades are formed of a heat-resistant metal material, the temperature of the turbine inlet gas can be increased without cooling the blades, and the output efficiency can be dramatically improved.

7. However, even if the blades are made of ceramic material as described above, the rotor blades must be fixed to the rotating shaft and the stationary blades must be fixed to the so-called casing by some means. In this case, the gas temperature is sufficiently raised to take advantage of the benefits of forming the blades using a ceramic material, so it is necessary to support the blades so as not to have a thermal effect on the members that support them. In addition, since changes in gas temperature due to load fluctuations are larger than normal, it is necessary to absorb the expansion and contraction of the blades due to these changes by some means to prevent excessive thermal stress from being applied to the blades. It is also important. Furthermore, it is also necessary to consider manufacturing and assembly aspects.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a turbine blade made of a ceramic material, which is easy to manufacture and assemble, and which also has a supporting member. Provides a gas turbine that is equipped with a support mechanism that can support the blades in a state that can effectively absorb the expansion and contraction of the blades due to temperature changes, thereby contributing to the improvement of output efficiency. It's about doing.

[Summary of the invention]

According to the present invention, an end portion of a stator vane formed of a ceramic material located on the rotation axis side is fixed to an inner support ring via a heat insulating member that contacts the end portion with a curved surface, and A heat insulating member having a curved surface contact with the end, a leaf spring that applies a pressing force in the direction of the rotating shaft to the heat insulating member, and a leaf spring that is orthogonal to the rotating shaft so that the pressing force of the leaf spring can be adjusted. It is characterized by providing a support mechanism that is fixed to the outer support ring via a bolt that is provided so as to be able to move forward and backward in the direction.

〔Effect of the invention〕

As described above, both ends of the stator vane in the direction orthogonal to the rotation axis are supported by the inner support ring and the outer support ring, respectively, via the heat insulating members. Since the high-temperature gas flows along the circumferential surface of the stator blade, the stator blade itself is heated to a high temperature. However, since both ends thereof are supported via a heat insulating member, the inner support ring and the outer support ring are not heated to a large extent. Therefore, these can be prevented from being affected by heat.

In addition, both ends of the stationary vane are supported via heat insulating members that contact curved surfaces with both ends, and the blade maintains its position holding function due to the elastic action of the leaf spring and the contact with curved surfaces. Combined with the bevel surface action, it is possible to quickly absorb the full amount of expansion and contraction of the stationary blades that occurs when the gas temperature changes.
As a result, it is possible to prevent the occurrence of a phenomenon in which the stator blades are destroyed due to excessive thermal stress being applied to the stator blades when the temperature changes. In addition, since bolts are provided in the above-mentioned relationship, the stationary blades can be installed and disassembled by setting the tightening amount of the bolts, which simplifies not only the production of each element but also the assembly. can'.

[Embodiments of the invention]

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

FIG. 1 schematically shows the entire gas turbine to which the present invention is applied. That is, numeral 1 in the figure indicates a cylindrical casing, and a rotary shaft 2 is rotatably mounted within this casing 1. A compressor and a turbine are arranged at both ends of the casing 1, and a combustor 5 is arranged between them. The compressor is constructed of an axial flow type in which guide vanes 6 fixed to the inner surface of the casing 1 and rotary vanes 7 fixed to the rotary shaft 2 are alternately arranged in the axial direction.

On the other hand, the turbine L is also fixed to the casing 1.
The rotor blades 9 and rotor blades 9 fixed to the rotating shaft 2 are arranged alternately in the axial direction.

The stationary blade 8 is made of a ceramic material such as 5i5N4. The rotor blades 9 are supported by the rotating shaft 2 by a known support mechanism, and the stationary blades 8 are supported by the support mechanism shown in FIG. Supported.

The support mechanism L is roughly divided into an element 13 that supports the end portion of the stationary blade 8 located on the rotation axis side, and an element 14 that supports the end portion located on the opposite rotation axis side. These elements 13, 14 and the stationary blade 8 are combined in the following manner to support the stationary blade 8. That is, as mentioned above, the stationary blade 8 is made of ceramic material and is formed in the known maple shape as a whole as shown in FIGS. The side end A and the end B on the opposite rotation axis side are formed into rounded and smooth curved surfaces not only in the thickness direction but also in the camber line direction. Then, element 13 and element 14 are connected via the above-mentioned smooth curved surface portion.
It is supported by

The element 13 is a heat-resistant material 16 made of, for example, a ceramic material and provided with a smoothly curved recess 15 that fits into the end A of the stationary blade 8.
Highly insulating material 17 made of ceramic, phyno, etc.
, a heat-resistant material 18, a high heat-insulating material 19, also made of ceramic material,
A heat insulating member 21 formed by laminating a heat-resistant material 20 in a fitted state as described above is fixed to an inner support ring 22 made of a metal material. That is, an annular projection 23 is formed on the outer peripheral surface of one end in the axial direction of the inner support ring 22.
Furthermore, a notch 24 that can fit into the annular projection 23 is formed at the corresponding end of the heat-resistant material 20 . Then, while the notch 24 and the annular protrusion 23 are fitted together, a presser ring 25 is applied to the end face of the heat-resistant material 20 located on the opposite side to the end where the notch 24 is provided. By fixing this presser ring 25 to the other end face of the inner support ring 22 with a bolt 26, the heat insulating member 2 is fixed to the inner support ring 22.

Thus, the outer support ring 12 is formed into a double cylinder shape consisting of an outer cylinder part 27 and an inner cylinder part 28 that are connected to each other by one end in the axial direction. An element 14 is arranged between the end B of the wing 8.

The element 14 includes a heat-resistant member 30 made of a ceramic material, for example, and has a smoothly curved recess 29 that fits into the end B of the stationary blade 8.
．． Highly insulating material 31 made of ceramic fiber, etc.
The same (heat-insulating member made of a heat-resistant material 32, a high-insulating material 33, and a heat-resistant material 34 made of ceramic materials are laminated in the above-mentioned order in a fitted state) -A leaf spring 36 and a presser plate 32 are applied to the outer surface of the material 35 in the above-mentioned order, and By pressing the outer surface of the presser plate 32 with bolts 38a and 38b inserted into screw holes provided in the inner cylindrical portion 28 so as to be movable forward and backward in a direction perpendicular to the rotating shaft 2, the end B of the stator blade 8 is pressed. is configured to be supported by the outer support ring 12.The axial position of the element 14 is restricted by a retaining ring 40 fixed to the inner surface of the outer cylinder part 27 with bolts 39 and by the outer support ring 12. This is done by a spacer 42 inserted between an annular protrusion 41 that protrudes inward and a heat-resistant material 34.The TFCS diagram only shows a support mechanism that supports one stationary blade 8. However, in reality, elements 13 , 14 are arranged circumferentially corresponding to each stationary vane 8 .

With such a configuration, both ends A of the stationary blade 8.

Since B is supported by the inner support ring 22 and the outer support ring 12 via the heat insulating member 21.35, the stator blade 8
The amount of heat transmitted to the inner and outer support rings 22.degree. 12 can be sufficiently reduced. Therefore, it is possible to protect the inner and outer support rings 22.12 from high heat without having to provide a special cooling mechanism for the inner and outer support rings 22.12. That is, it is possible to alleviate the thermal influence on the blade support material that tends to occur when the blade is formed of a ceramic material and the gas temperature is increased. Also,
The ends A and B of the stationary blade 8 are in curved contact with the heat insulating member 21.35, and the leaf spring 36 exerts a pressing force on the rotating shaft side, so that sudden changes in gas temperature can be prevented. Even if the stationary blade 8 expands and contracts in the thickness direction, height direction, and camber line direction due to the change, this expansion and contraction is absorbed by the elastic action of the leaf spring 360 and the surface action of the curved surface contact. Therefore, it is possible to prevent the stator blade 8 from being damaged by thermal stress, which is likely to occur in such a case. Further, it can be easily disassembled by loosening the bolts 38a and 38b with the retainer rings 25, 40 removed, and can be easily assembled by performing the operations in reverse to the above. Furthermore, since it does not require so-called parts with high dimensional accuracy, it is easy to make movies, and the above-mentioned effects can be obtained.

Note that the present invention is not limited to the embodiments described above. For example, as shown in FIG. 5, a stator blade 8a made of a ceramic material and having a hollow interior to relieve concentration of thermal stress may be used as the stator blade. Furthermore, the number of laminated heat insulating members is not particularly limited. Further, as the leaf spring, it is of course possible to use a stacked leaf spring having a plurality of layers laminated.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of a gas turbine according to an embodiment of the present invention, Fig. 2 is a schematic longitudinal sectional view of the main parts of the gas turbine, and Fig. 3 is a diagram showing only the stationary blades of the gas turbine. FIG. 4 is a cross-sectional view of the stator blade taken along the line EE in FIG. 2 and viewed in the direction of the arrow, and FIG. 5 is a cross-sectional view showing a modified example of the stator blade. 2...Rotating shaft, L...Turbine, 8...Stator blade, 9
... Moving blade, 12... Outer support ring, 21.35.
...Insulating member, 22...Inner support ring, 36...
Boards, etc., 38a, 38b--Gruto. Applicant Makoto Ishizaka, Director General of the Agency of Industrial Science and Technology - Figure 1 Figure 2

Claims (1)

[Claims] In a gas turbine in which the blades of the turbine are formed of a ceramic material, the stator blades of the turbine are arranged such that an end portion of the stator blade located on the rotating shaft side is connected to an inner support ring via a heat insulating member having a curved surface contact with the end portion. a heat insulating member fixed to the stator vane, the end of which is located on the opposite side of the rotational shaft to be in curved contact with the end; a leaf spring that applies a pressing force in the direction toward the rotational shaft to the heat insulating member; and a pressing force of the leaf spring. A gas turbine is fixed to an outer support ring via a bolt provided to be movable in a direction orthogonal to a rotating shaft so as to be able to adjust pressure.