JPH0612049B2 - Turbine nozzle vanes and nozzles - Google Patents

Description

Description: [Object of the invention] (Field of industrial application) The present invention relates to a nozzle blade and a nozzle of a turbine, in particular, a gas turbine.

(Prior Art) FIG. 8 is a diagram showing a schematic configuration showing a nozzle portion of a general turbine, in which a large number of nozzle blades 3 are arranged between an inner ring 1 and an outer ring 2, and The inner end surface is fixed to the outer surface of the inner ring 1, and the outer end surface of the nozzle blade 3 is fixed to the inner surface of the outer ring 2 by welding.

(Problems to be Solved by the Invention) In order to improve the thermal efficiency of a gas turbine, increasing the turbine inlet temperature is an effective method.
For this reason, super heat-resistant alloys have been studied as materials for moving blades and nozzle blades, and research on cooling methods has also been conducted.However, these have almost reached their limits, and recently, ceramic materials with higher heat resistance than heat-resistant alloys have been used for gas turbines. Research is being conducted for use as parts. When using a gas turbine nozzle blade,
One of the methods that has been attempted in the past is to replace the metal nozzle blades with ceramics as they are, but due to a sudden change in the thickness and shape of the connection between the blade and shroud, there is a large unsteady state. There is a problem that thermal stress is generated and it is destroyed. Therefore, because ceramic has a property of being weak in tension but strong in compression, a combination of ceramic and metal is used.For example, a nozzle blade of a type in which ceramic is mainly subjected to compressive stress and metal bears tensile stress is Kaisho 62
It is proposed as described in Japanese Patent Publication No. 605. However, when a metal mandrel is passed through the inside of the blade, cooling air is required to cool the mandrel, which reduces the performance improvement rate and complicates the structure of the ceramic component, making it difficult to manufacture. there were.

In view of such a point, the present invention has an object to obtain a nozzle blade that does not require cooling air and has high reliability and good manufacturability, and a nozzle using the nozzle blade.

[Structure of Invention]

(Means for Solving the Problem) A turbine nozzle blade according to the present invention has a plate-shaped blade portion and the blade portion integrally projected from both ends of the blade portion in a direction orthogonal to a surface including the blade portion. In addition, it has an inner peripheral wall portion and an outer peripheral wall portion that form a passage of working gas for one pitch, and the back surface of the blade portion and the gas passage surfaces of the inner peripheral wall portion and the outer peripheral wall portion are connected by a smooth curved surface. At the same time, the ventral surface of the wing portion and the anti-gas passage surface of the inner peripheral wall portion and the outer peripheral wall portion are connected by a smooth curved surface and are formed in a U-shaped cross section.

Further, in the turbine nozzle according to the present invention, the nozzle vanes having a U-shaped cross section are arranged in the circumferential direction between the inner and outer cylinders, and the anti-gas passage surface of the inner peripheral wall portion and the anti-gas between the inner cylinder and the outer peripheral wall portion. A heat insulating material is interposed between the passage surface and the outer cylinder.

(Operation) By arranging and combining the nozzle blades in the circumferential direction, the inner and outer peripheral wall portions form an annular passage and serve as a working gas flow passage, while the blade portions form an annular blade row to accelerate the working gas. Change the flow direction. Moreover, the nozzle blade has a shell shape that does not have a sudden change in wall thickness or bending, and because of no cooling, the temperature is uniform and thermal stress is prevented from occurring, and there is no stress concentration part, improving reliability, It can also be made of ceramic, the heat resistance can be improved, and the simple shape facilitates manufacturing.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the main body of the nozzle blade, in which the nozzle blade 10 is made of a heat-resistant material such as ceramic, and the blade portion 10a has a bent plate shape.
The wing portion 10a is integrally formed with the inner peripheral wall portion 10b and the outer peripheral wall portion 10c protruding from each of both ends in a direction orthogonal to the plane including the wing portion 10a, and constitutes one pitch.
FIG. 2 is a cross-sectional view taken along the line III-III of FIG. 1, showing a rear surface 10d of the blade portion and a gas passage surface 10e of the inner peripheral wall portion 10b,
The gas passage surface 10f of the outer peripheral wall portion 10c is connected with a smooth curved surface, and the abdominal surface 10g of the blade portion, the anti-gas passage surface 10h of the inner peripheral wall portion 10b, and the anti-gas passage surface 10i of the outer peripheral wall portion 10c are also smooth curved surfaces. They are connected and formed in a U-shaped cross section.
The thickness of the wing portion, the inner peripheral wall portion, and the outer peripheral wall portion, including the boundary portion, changes continuously and smoothly. Further, anti-rotation grooves 10j, 10k are provided on the respective anti-gas passage surfaces of the inner peripheral wall portion 10b and the outer peripheral wall portion 10c, respectively.

Further, the blade portion 10a is provided with an inclination angle θ on the inner peripheral wall portion 10h near the center portion.

FIG. 3 shows a cross section of a turbine nozzle in which this nozzle blade is assembled, and FIG. 4 shows a cross section taken along the line I--I of FIG. The plurality of nozzle blades 10 form an annular blade row, and each nozzle blade has the tip of the presser bar 12 fitted in the detent grooves 10j and 10k provided in the inner peripheral wall portion and the outer peripheral wall portion. The presser bar 12 is the fifth
As shown in the figure, it is composed of a metal shaft portion 12a and a ceramic head portion 12b attached to the tip thereof, and a collar portion 12c is provided on the shaft portion, and is attached to a metal outer cylinder 13 and an inner cylinder 14. And is pressed against the nozzle blade 10 by the spring 15. The nozzle blade 10 includes an outer cylinder 13 and an inner cylinder 14.
The nozzle blade 10, the outer cylinder 13, and the nozzle blade 1 are attached by being sandwiched between the front heat shield 16 and the rear heat shield 17 mounted on the
A heat shield 18 is interposed between 0 and the inner cylinder 14. As the heat shield 18, for example, a woven cloth material of ceramic fibers is suitable. The positions where the inner peripheral wall portions 10b of the nozzle blades 10 are adjacent to each other and the outer peripheral wall portion 10c.
A seal plate 19 is provided at a position adjacent to each other on the side opposite to the gas passage surface of the nozzle blade.
9 is a holding rod (not shown) similar to the holding rod 12 of the nozzle blade
It is pressed by the nozzle blade 10 and is pressed against the nozzle blade 10. A cooling passage 20 is provided in the outer cylinder 13 and the inner cylinder 14.

Then, the blade portion 10a of the nozzle blade changes the flow direction of the gas to increase the speed like the normal nozzle blade, and the inner peripheral wall portion 10b and the outer peripheral wall portion 10c form an annular gas passage. As the force from the gas, a tangential force in the circular direction and an axial force in the gas flow direction act on the nozzle blades. Tangent force is 12
The axial force is received by the inner cylinder and the outer cylinder via the rear heat shield 17. The presser bar 12 is the nozzle blade 10
And the outer cylinder 13 and the inner cylinder 14 absorb the difference in thermal expansion caused by changes in operating conditions. Further, the seal plate 19 closes the gap formed between the inner and outer peripheral wall portions of the adjacent nozzle blades, and prevents gas from flowing into the outer cylinder or inner cylinder side made of metal. On the other hand, the outer cylinder 13 and the inner cylinder 14 made of metal are provided in the cooling passage 20.
It is cooled by the cooling air passing through, and the heat shield 18 reduces heat transfer from the nozzle blade 10 to the inner and outer cylinders.
Therefore, the cooling air required for cooling the inner and outer cylinders is reduced.

In addition, supplementing the secondary flow, in the conventional turbine nozzle blade, the nozzle blade 3 is linear as shown in FIG.
It is at a right angle to the inner ring 1 and the outer ring 2. Therefore, since the pressure on the abdominal surface 3g is higher than the pressure on the back surface 3d, a boundary layer flow 21 is generated, and a vortex 22 caused by this flow is generated, resulting in a pressure loss. However, in the nozzle blade of the present invention, the abdominal surface 10g faces the inner peripheral wall on the inner peripheral wall side and faces the outer peripheral wall on the outer peripheral wall side, so the development of the boundary layer flow is suppressed and the loss is reduced.

FIG. 6 is a view showing another embodiment of the present invention, in which a piece 23 is interposed between the presser bar 12 and the nozzle blade 10 to support the nozzle blade 10. As shown in FIG. 7, the piece 23 has a claw 23a fitted to one side of the nozzle blade 10,
Receives the circumferential force of the nozzle blade. Further, the anti-gas side has a groove 23b into which the presser bar is fitted, and the presser bar 12 presses the bridge 23 against the nozzle blade. And this piece 23 also has a sealing effect like the sealing plate 19.

Regarding the effect of reducing the secondary flow loss, in the example of FIG. 2, the nozzle blade effective portion has a partial straight portion, but the present invention is not limited to such a shape, and the entire effective portion is effective. May be formed with a gentle curve.

〔The invention's effect〕

As described above, since the thickness of the nozzle blade of the present invention does not change suddenly and has a shell shape with a U-shaped cross section that is smooth to curved, the entire nozzle blade is uniformly exposed to the mainstream gas. In addition, the temperature distribution is relatively non-uniform due to no cooling, no large unsteady thermal stress is generated, the reliability is high, and the manufacturing is easy. Further, since it is uncooled, cooling air for cooling the nozzle blade is not necessary. Furthermore, since a heat shield is interposed between the nozzle blade and both the inner and outer cylinders, heat transfer from the nozzle blade to both the inner and outer cylinders is reduced, and the amount of cooling air required for both the inner and outer cylinders can be reduced. it can. Moreover, since the nozzle blade is integrally formed of the blade portion and the inner and outer peripheral wall portions, the heat shield does not need to have a function for maintaining the shape of this structure, and a material excellent in heat insulation is used. Can be used.

[Brief description of drawings]

1 is a view showing a nozzle blade of the present invention, and FIG. 2 is a view of FIG.
A cross-sectional view taken along line III-III, FIG. 3 is a view showing a nozzle in which the nozzle blade of the present invention is incorporated between an outer cylinder and an inner cylinder, and FIG. 4 is a cross-sectional view taken along the line I-I in FIG. FIG. 5 is a view showing a presser bar, FIG. 6 is a second embodiment of the present invention, FIG. 7 is a view showing the shape of the bridge of FIG. 6, and FIG. 8 is a conventional nozzle partial view. 10 ... Nozzle blade, 12 ... Presser bar, 13 ... Outer cylinder, 1
4 ... Inner cylinder, 15 ... Spring, 16 ... Front heat shield, 17
…… Rear heat shield, 18 …… Heat shield, 19 …… Seal plate,
20 ... Cooling channel, 23 ... Piece.

Claims (2)

[Claims] 1. A plate-shaped wing portion and integrally projecting from both ends of the wing portion in a direction orthogonal to a surface including the wing portion, and together with the wing portion, a passage for one pitch of working gas is formed. An inner peripheral wall portion and an outer peripheral wall portion, the back surface of the blade portion and the gas passage surface of the inner peripheral wall portion and the outer peripheral wall portion are connected by a smooth curved surface, and the belly surface of the blade portion and the inner peripheral wall portion and the outer periphery A turbine nozzle blade characterized in that the anti-gas passage surface of a wall sheet is connected with a smooth curved surface and is formed in a U-shaped cross section. 2. A plate-shaped wing portion and integrally projecting from both ends of the wing portion in a direction orthogonal to a surface including the wing portion, and together with the wing portion, a passage for one pitch of working gas is formed. Nozzle blades having a U-shaped cross section having an inner peripheral wall portion and an outer peripheral wall portion are circumferentially arranged between the inner and outer cylinders, and an anti-gas passage surface of the inner peripheral wall portion and an anti-gas between the inner cylinder and the outer peripheral wall portion are arranged. A turbine nozzle characterized in that a heat shield is interposed between the passage surface and the outer cylinder.