JPH0893404A - Turbine nozzle and turbine rotor blade - Google Patents

Abstract

PURPOSE: To remarkably improve the turbine following control by reducing the loss of secondary flow near the wall faces of a diaphragm inner wheel and a diaphragm outer wheel and at the same time increasing the flow rate passing the center part. CONSTITUTION: A nozzle blade 11 to be installed in a circular flow route 14 between a diaphragm inner wheel 13 and a diaphragm outer wheel 12 is so curved as to make a cross-section base line E have one minimum point Pc at the center part of the height of the blade in the fluid flowing out side and one maximum point Pa, Pb respectively between the minimum point Pc and a blade tip end and between the minimum point Pc and the blade base in the case the nozzle blade cross-section at every height position is moved in circumferential direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine nozzle and a turbine rotor blade for improving turbine stage performance by controlling a flow rate distribution in a radial direction to increase a flow rate to a high efficiency section.

[0002]

2. Description of the Related Art Many techniques have been adopted so far for the purpose of improving the performance of turbines. Among various performance improving techniques, the improvement of internal efficiency is required for turbines of any cycle or fluid condition. However, since it can be applied, its application range is wide. Of the turbine internal loss, 2
Since the secondary flow loss is a loss common to the turbine stage, the improvement measure thereof largely contributes to the improvement of the turbine efficiency.

In a turbine nozzle of a general axial flow turbine, as shown in FIG. 11, a plurality of nozzle blades 1 are fixedly installed in an annular flow path 4 formed between a diaphragm outer ring 2 and a diaphragm inner ring 3. The moving blade (FIG. 4) is arranged on the downstream side so as to face each nozzle blade 1.

A mechanism for generating a secondary flow in the nozzle blade 1 of the turbine nozzle will be described with reference to FIG.

When the working fluid such as high-pressure steam flows in the inter-blade passage between the adjacent nozzle blades 1 and 1, the working fluid is bent into an arc shape in the passage and flows from the back surface B of the nozzle blade 1 at this time. A centrifugal force is generated in the direction of the abdominal surface F, but since the centrifugal force and the static pressure are parallel to each other, the static pressure on the abdominal surface F of the nozzle blade 1 increases, and the flow velocity of the working fluid on the back surface B of the nozzle blade 1 increases. Since it is large, the static pressure is low. Therefore, in the flow path, a pressure gradient is generated from the ventral surface F side of the nozzle blade 1 to the back surface B side. This pressure gradient is the same also in the layer having a low flow velocity formed on the peripheral wall surfaces of the diaphragm outer ring 2 and the diaphragm inner ring 3, that is, the boundary layer.

On the other hand, in the vicinity of the boundary layer formed on the peripheral wall surfaces of the diaphragm outer ring 2 and the diaphragm inner ring 3,
Since the flow velocity is small and the centrifugal force acting is small, the nozzle blade 1
Can not resist the pressure gradient from the abdominal surface F side to the back surface B side of
A secondary flow 6 occurs in the direction from the ventral surface F side of the nozzle blade 1 to the back surface B side.

When the secondary flow 6 flows from the ventral surface F side of the nozzle blade 1 toward the back surface B side, the secondary flow 6 collides with the back surface B side of the nozzle blade 1 and is rolled up, and the inner ring side and the outer ring of the nozzle blade 1 are formed. The secondary flow vortices 7a and 7b are generated at both joint ends on the side, and the energy held by the working fluid is partly dissipated to form the secondary flow vortices 7a and 7b.

As described above, the secondary flow vortices 7a and 7b generated in the nozzle passage generate a non-uniform flow of the working fluid,
Various turbine nozzles have been studied in order to reduce the secondary flow loss caused by the secondary flow vortices 7a and 7b generated in the nozzle flow passage because the nozzle performance is significantly deteriorated.

As a turbine nozzle for reducing the secondary flow loss, as shown in FIG. 12, there is a turbine nozzle having a shape in which the nozzle blade is attached to be inclined with respect to a radial line passing through the center of rotation. In this turbine nozzle, the inclined nozzle vane 1b has a radial line E passing through the center of rotation of the rotor disk.
It is installed at an angle with respect to. Therefore, the inter-blade passage formed between the inclined nozzle vanes 1b and 1b is an inclined curved pipe, and the velocity vector in the inter-blade passage is in the direction of the diaphragm inner ring 3. As a result, the growth of the boundary layer generated near the wall surface of the diaphragm inner ring 3 is suppressed, and the secondary flow is also reduced. As a result, the size of the secondary flow vortex 7a generated in the nozzle flow path becomes smaller than in the case of the turbine nozzle of the type shown in FIG. 11, and the secondary flow loss at the root of the nozzle blade is significantly reduced.

As a turbine nozzle for reducing the secondary flow loss, as shown in FIG. 13, there is a turbine nozzle having a shape in which a nozzle blade is curved and attached to a radial line E passing through the center of rotation of a rotor disk. . The curved inclined nozzle blade 1c of this turbine nozzle has the configuration and operation shown in FIG.
In the curved nozzle blade 1c of the turbine nozzle shown in FIG. 13, the velocity vector in the blade-to-blade flow path is the same as that of the inclined nozzle blade 1b of the turbine nozzle shown in FIG. Since the diaphragm is directed toward the outer ring 2, the growth of the boundary layer can be suppressed on both the inner ring of the diaphragm and the outer ring, and the secondary flow is also inclined nozzle blade 1
It is smaller than b. As a result, the secondary flow loss at the root portion and the tip portion of the nozzle blade is significantly reduced as compared with the turbine nozzle of the type shown in FIG.

[0011]

In the turbine nozzle having the curved inclined nozzle 1c, since the velocity vector is in the direction of the diaphragm inner ring 3 on the root side and in the direction of the diaphragm outer ring 2 on the tip side, the blade height in FIG. The flow rate distribution diagram for the ratio is the flow rate distribution 8 indicated by the solid line. Since the velocity vector is oriented toward the wall surface in the vicinity of the wall surface of the diaphragm inner ring 3, the secondary flow loss can be reduced, but the loss distribution 9 shown by the solid line in the loss distribution diagram for the blade height ratio in FIG.
The flow rate in the efficient portion of the central portion of the flow passage is smaller than that of the conventional nozzle, and the contribution to the paragraph efficiency in the central portion of the flow passage is small.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and a turbine nozzle having a simple structure for reducing the secondary flow loss and controlling the flow rate distribution to improve the turbine stage performance, and It is intended to provide a turbine rotor blade.

[0013]

A turbine nozzle according to a first aspect of the present invention has a plurality of nozzle blades arranged in a row in the circumferential direction of an annular flow path formed between an inner ring of a diaphragm and an outer ring of the diaphragm. In a turbine nozzle with blades fixed at the joint end on the inner ring side of the diaphragm, the nozzle blade cross section at each height position is moved in the circumferential direction, and the cross section reference line is located on the fluid outflow side with one local minimum point at the blade height center. And has a curved feature such that it has one local maximum between the local minimum and the blade tip and between the local minimum and the blade root.

A turbine nozzle according to a second aspect of the present invention is the turbine nozzle according to the first aspect, wherein the root-side maximum point of the cross-section reference line is at a blade height ratio of 0.1 to 0.5 and the tip-side maximum point is The blade height ratio is 0.5 to 0.9.

According to a third aspect of the present invention, there is provided a turbine rotor blade having a plurality of rotor blades arranged in a row in an implanted portion of a turbine rotor. The cross-section reference line with respect to the reference radial line on the fluid outflow side and has one minimum point at the blade height center and one between the minimum point and the blade tip and between the minimum point and the blade root. It has a curved feature with a maximum point.

A turbine rotor blade according to a fourth aspect is the turbine rotor blade according to the third aspect, in which a root-side maximum point of a cross-section reference line is located at a blade height ratio of 0.1 to 0.5 and a tip-side maximum point. The point is located at a position of 0.5 to 0.9 in terms of blade height ratio.

According to a fifth aspect of the turbine nozzle, a plurality of nozzle blades are arranged in a row in the circumferential direction of the annular flow passage formed between the inner ring of the diaphragm and the outer ring of the diaphragm, and each nozzle blade is arranged on the inner ring side of the diaphragm. In the turbine nozzle fixed at the joint end, the cross section of the nozzle blade at each height position is moved in the axial direction, and the section reference line has one local minimum point at the blade height center on the fluid outflow side and the local minimum point and blade. It has a curved feature with one local maximum between the tips and between the local minimum and the blade root.

A turbine nozzle according to a sixth aspect of the present invention is the turbine nozzle according to the fifth aspect, wherein the root-side maximum point of the cross-section reference line is at a blade height ratio of 0.1 to 0.5 and the tip-side maximum point is The blade height ratio is 0.5 to 0.9.

According to a seventh aspect of the present invention, there is provided a turbine rotor blade having a plurality of rotor blades arranged in a row at an implanting portion of a turbine rotor. Moves and has a cross-section reference line on the fluid outflow side with respect to the reference radial line, and has one minimum point at the blade height center and one maximum point between the minimum point and the blade tip and between the minimum point and the blade root. It has features that are curved to have points.

A turbine rotor blade according to an eighth aspect is the turbine rotor blade according to the seventh aspect, wherein a root-side maximum point of a cross-section reference line is located at a blade height ratio of 0.1 to 0.5, and a tip-side maximum point. The point is located at a position of 0.5 to 0.9 in terms of blade height ratio.

[0021]

In the turbine nozzle of claim 1, the nozzle blade section at each height position is moved in the circumferential direction, and the section reference line has one local minimum point and a local minimum point at the blade outlet center on the fluid outflow side. 1 between the point and the tip of the wing and between the minimum point and the root of the wing
The curved shape with two maximum points reduces the secondary flow loss in the vicinity of the inner and outer peripheral wall surfaces between the blade rows, and the velocity vector is directed to the central height part, which is efficient at the central height position. The rate of flow through the section increases.

According to the turbine moving blade of claim 3, the moving blade cross section at each height position is moved in the circumferential direction, and the cross section reference line is located on the fluid outflow side with respect to the reference radial line. By having a curved shape that has a minimum point and one maximum point between the minimum point and the blade tip and between the minimum point and the blade root, the secondary flow loss near the inner and outer peripheral wall surfaces between the blade rows is reduced. As the velocity decreases, the velocity vector goes to the central height,
The rate of flow rate passing through the efficient portion at the central height position increases.

In the turbine nozzle of the fifth aspect, the nozzle blade cross section at each height position is moved in the axial direction, and the section reference line has one local minimum point at the blade height center on the fluid outflow side and the local minimum point. By adopting a curved shape with one maximum point between the blade tip and the blade tip and between the minimum point and the blade root, secondary flow loss near the inner and outer peripheral wall surfaces between the blade rows is reduced, and the velocity vector is The ratio of the flow rate passing through the efficient portion at the central height position toward the swell increases.

In the turbine moving blade of claim 7, the moving blade cross section at each height position is moved in the axial direction, and the cross section reference line is located at the center of the blade height on the fluid outflow side with respect to the reference radial line. By having a curved shape that has points and one maximum point between the minimum point and the blade tip and between the minimum point and the blade root, secondary flow loss near the inner and outer wall surfaces between the blade rows is reduced. Then, the velocity vector is directed to the central height portion, and the rate of flow rate passing through the efficient portion at the central height position increases.

[0025]

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

FIG. 1 is a perspective view of a part of the structure of a turbine nozzle according to the present invention as viewed from the nozzle outlet side. In a turbine nozzle 10, a plurality of nozzle blades 11 are provided between a diaphragm outer ring 12 and a diaphragm inner ring 13. It is configured by arranging in a row at a predetermined interval in the annular flow path 14 formed in the circumferential direction, and fixing the root part and the tip part of each nozzle blade 11 to the diaphragm inner ring 13 and the diaphragm outer ring 12. There is. The symbol I indicates the direction of fluid flow into the annular flow path 14.

FIG. 2 is a view showing the trailing edge shape of the nozzle blade 11 of the turbine nozzle 10 according to the present invention, and shows the relationship between the radial line E passing through the axial center of the turbine nozzle 10 and the trailing edge line of the nozzle blade 11. Has been done. That is, the nozzle blade 11
Moves in the circumferential direction of the nozzle blade cross section at each height position, and one local minimum point Pc at the blade height center with respect to the radial line E where the nozzle blade cross-section reference line 11a passes through the axial center.
And one maximum point Pb between the minimum point Pc and the blade tip.
And has a characteristic that it is curved so as to have one maximum point Pa between the minimum point Pc and the blade root. Root side maximum point Pa
Is located at a distance R from the diaphragm inner ring 13, the tip-side maximum point Pb is located at a distance T from the diaphragm outer ring 12, and the minimum point Pc is located at the PCD portion G.

Each nozzle blade 11 has a diaphragm outer ring 12
By arranging in a row in the annular flow path 14 between the diaphragm and the inner ring 13 of the diaphragm at a predetermined interval in the circumferential direction, the flow path between the nozzle blades 11 becomes a curved pipe, and the velocity vector D between the nozzle blades is increased. 2, is directed toward the diaphragm inner ring 3 side at the root of the nozzle blade 11, directed toward the diaphragm outer ring 2 side at the tip of the nozzle blade 11, and toward the PCD section G at the center of the nozzle blade 11. Be oriented.

Thus, the turbine nozzle 1 according to the present invention
As shown in FIG. 5, 0 is a W-shaped flow distribution 16 in contrast to the flow distribution 15 of the conventional nozzle blade whose trailing edge coincides with the radial line E. This flow rate distribution 16 is similar to the flow rate distribution 8 of the conventional curved nozzle, and is at the base (blade height ratio 0 position).
The flow rate at the tip portion (at a blade height ratio of 1.0 position) tends to flow higher than that of the conventional blade, and the flow rate at the central portion or more is equal to or higher than that of the conventional blade.

FIG. 6 shows a loss distribution diagram with respect to the blade height ratio. The loss distribution (dotted line) of the turbine nozzle 10 according to the present invention is shown by reference numeral 17, and the loss distribution of the turbine nozzle of the conventional curved nozzle vane 1c ( The solid line is indicated by reference numeral 18.

That is, in the turbine nozzle of the curved nozzle 1c, the velocity vector D near the root and the tip of the conventional curved nozzle blade 1c is directed toward the diaphragm inner ring 3 side and the diaphragm outer ring 2 side, respectively, to suppress secondary flow loss. Therefore, the loss distribution 18 becomes smaller than the loss distribution 9 of the turbine nozzle of the conventional nozzle blade 1b by the amount of the secondary flow loss suppressed near the root portion and the tip portion.

On the other hand, in the turbine nozzle 10 according to the present invention, the velocity vector D is directed toward the diaphragm inner ring 13 side and the diaphragm outer ring 12 side at the root portion and the tip portion, respectively, similarly to the conventional curved nozzle blade 1c. ,
The loss distribution 17 has almost the same level as the loss distribution 18 of the turbine nozzle of the curved nozzle blade 1c.

FIG. 7 is a power ratio distribution diagram with respect to the radial blade height ratio obtained by FIGS. 5 and 6. 7, the output distribution (dotted line) of the turbine nozzle 10 according to the present invention is shown by reference numeral 19, the loss distribution (solid line) of the turbine nozzle of the conventional nozzle blade 1b is shown by reference numeral 20, and the turbine of the conventional curved nozzle blade 1c is shown. The loss distribution (solid line) of the nozzle is indicated by reference numeral 21.

In the turbine nozzle 10 according to the present invention, since the nozzle blade 11 has a structure in which a large amount of flow flows in the highly efficient central portion, a high output is obtained in this portion, and the root portion and the tip portion are also secondary. By reducing the flow loss, an output higher than the output distribution 20 of the turbine nozzle of the conventional nozzle blade 1b can be obtained.

FIG. 8 is a power distribution ratio diagram of the turbine nozzle according to the present invention on the root side with respect to the blade height of 0.5. The position of the maximum point Pa on the diaphragm inner ring 13 side and the curved nozzle blade 1c.
It shows the relationship of the output ratio to. In FIG. 8, the horizontal axis represents the blade cross-section position when the blade height is 1.0, and the vertical axis represents the radial power distribution in the curved nozzle as 1.0 at each blade cross-section position to make it dimensionless. The output ratio is shown.

In the turbine nozzle 10 according to the present invention, the output curve has a maximum point P between 0.1 and 0.5 in the blade height ratio.
When a is positioned, a higher output than that of the conventional curved nozzle blade 1c is obtained, and the turbine efficiency is significantly improved.

FIG. 9 is an output distribution ratio diagram of the turbine nozzle according to the present invention on the tip side with respect to the blade height of 0.5. The position of the maximum point Pa on the diaphragm inner ring 13 side and the curved nozzle blade 1c.
It shows the relationship of the output ratio to.

In the nozzle blade 11 of the turbine nozzle 10 according to the present invention, the output curve has a blade height ratio of 0.5 to 0.9.
The conventional curved nozzle blade 1 when the maximum point Pb is located between
A higher output than that of c is obtained, and the turbine efficiency is significantly improved.

In the turbine nozzle 10 according to the present invention, when the maximum point is 0.5, the shape is the same as that of the conventional curved nozzle blade 1c, so that the output ratio is at the same level. Further, when the maximum point is located at a blade height position of 0.1 or less at the root side or 0.9 or more at the tip, the effect of suppressing the secondary flow due to the curved shape in the vicinity of each wall surface becomes small, and the output Is smaller than that of the conventional curved nozzle blade 1c.

FIG. 3 shows a turbine rotor blade 30 according to the present invention. In this turbine rotor blade 30, a plurality of rotor blades 32 are arranged in a row in an implanted portion 31a of a turbine rotor 31, and each rotor blade 3 is provided.
It is configured by fixing the outer peripheral end of 2 with a shroud 33. The turbine rotor blade 30 is disposed downstream of the turbine nozzle 10 so that the rotor blade 32 faces the nozzle blade 11.

As in the turbine blade 11 shown in FIG. 2, each blade 32 of the turbine blade 30 is moved in the circumferential direction in the blade cross section at each height position, and the section reference line becomes the reference radial line. On the other hand, it has a feature that it has one local minimum point at the blade height center on the fluid outflow side and one local maximum point between the local minimum point and the blade tip and between the local minimum point and the blade root.

Since each moving blade 32 of the turbine moving blade 30 is arranged in the annular flow path, the flow path between the moving blades 32 becomes a curved pipe, and the velocity vector D between the blades is determined by the root portion of the moving blade 32. Is directed toward the turbine rotor 31 side, the tip end of the moving blade 32 is directed toward the diaphragm outer ring 12 side, and P is provided at the central portion of the moving blade 32.
The CD section G is directed. Therefore, the moving blade 32 of the turbine moving blade 30 has the same effect as the nozzle blade 11 of the turbine nozzle 10.

FIG. 4 is a view of another embodiment of the turbine nozzle and the turbine rotor blade according to the present invention as seen from the circumferential direction. Each nozzle blade 41 of the turbine nozzle 40 of this embodiment is shown.
And each rotor blade 43 of the turbine rotor blade 42 has a cross-section reference line 4
1a and 43a are on the fluid outflow side with respect to the reference radial line,
It has a feature with one local minimum and one local maximum between the local minimum and the blade tip and between the local minimum and the blade root.

That is, in the nozzle blade 41 of the turbine nozzle 40, the cross-section reference line 41a has one local minimum point at the blade height center and one local maximum point and one local minimum point between the local minimum point and the blade tip. Since the velocity vector D has a feature that it is curved so as to have one maximum point between the roots, the velocity vector D is directed toward the diaphragm inner ring 13 at the root portion and toward the diaphragm outer ring 12 at the tip portion, so that the secondary flow loss A reduction effect is seen, and the flow rate to the low loss portion in the central portion is increased by the concave portion in the central portion, and the same effect as that of the nozzle blade 11 having the same shape in the circumferential direction is obtained.

In the rotor blade 43 of the turbine rotor blade 42, the cross-section reference line 43a also has one local minimum point at the blade height center and one local maximum point and one local minimum point between the local minimum point and the blade tip. Since the blade has a characteristic that it is curved so as to have one maximum point between the blade roots, the velocity vector D is directed toward the diaphragm inner ring 13 at the root portion and toward the diaphragm outer ring 12 at the tip portion, so that the secondary flow loss occurs. And the flow rate to the low loss portion in the central portion is increased by the concave portion in the central portion, and the same effect as that of the moving blade 32 having the same shape in the circumferential direction is exhibited.

The operation of the nozzle blade of the turbine nozzle is shown in FIG.
Described in.

The fluid that has passed through the nozzle vanes flows out from the nozzle vanes at an angle α. When the nozzle outflow velocity is C2, the circumferential component vector of the nozzle outflow velocity is Ct, and the axial component vector of the nozzle outflow velocity is Ca.

In the embodiment shown in FIG. 1, by moving the cross section of the nozzle blade in the circumferential direction, the circumferential component vector Ct of the nozzle outflow velocity is made to have a radial distribution as shown in FIG.
The secondary flow loss is reduced and the flow rate ratio to the efficient portion of the central portion is increased.

In the embodiment shown in FIG. 3, the axial component vector Ca of the nozzle outflow velocity is set to a radial distribution as shown in FIG. 2 so that the secondary flow loss is reduced and the flow rate ratio to the efficient portion of the central portion is set. The effect is to increase.

That is, in the embodiment shown in FIG. 1, the cross-sectional position is defined so as to have the above-mentioned shape on the fluid outflow side in the circumferential direction, and in the embodiment shown in FIG. Is defined as having the above-mentioned shape on the fluid outflow side in the axial direction.

[0051]

As described above, according to the turbine nozzle of the first aspect, the nozzle blade section at each height position is moved in the circumferential direction, and the section reference line is 1 at the blade height center portion on the fluid outflow side. By having two local minimum points and one local maximum point between the local minimum point and the blade tip and between the local minimum point and the blade root, the secondary flow loss near the wall surface of the diaphragm inner ring and the diaphragm outer ring is reduced. The turbine stage performance can be significantly improved by reducing the flow rate and increasing the flow rate ratio passing through the central portion.

Further, in the turbine moving blade of claim 3, the moving blade cross section at each height position is moved in the circumferential direction, and the cross section reference line is at the blade outflow center with respect to the reference radial line at the blade height center portion. The secondary flow loss near the wall surface of the turbine rotor and the outer ring of the diaphragm by having one local minimum point and one local maximum point between the local minimum point and the blade tip and between the local minimum point and the blade root. The turbine stage performance can be significantly improved by reducing the flow rate and increasing the flow rate ratio passing through the central portion.

Further, in the turbine nozzle of claim 5, the nozzle blade section at each height position is moved in the axial direction, and the section reference line has one local minimum point at the blade height center on the fluid outflow side. By curving so as to have one maximum point between the minimum point and the blade tip and between the minimum point and the blade root, the secondary flow loss near the wall surface of the diaphragm inner ring and the diaphragm outer ring is reduced, and the central portion is reduced. Turbine stage performance can be significantly improved by increasing the rate of flow through.

According to a seventh aspect of the present invention, in the turbine rotor blade, the rotor blade section at each height position is moved in the axial direction, and the section reference line is at the blade outflow side with respect to the reference radial line at the blade height center portion. By having two local minimum points and one local maximum point between the local minimum point and the blade tip and between the local minimum point and the blade root, the secondary flow loss near the wall surface of the turbine rotor and the outer ring of the diaphragm can be reduced. The turbine stage performance can be significantly improved by reducing the flow rate and increasing the flow rate ratio passing through the central portion.

[Brief description of drawings]

FIG. 1 is a perspective view of a nozzle blade of a turbine nozzle according to the present invention as viewed from a fluid outflow side.

FIG. 2 is a view showing a trailing edge shape of a nozzle blade of a turbine nozzle according to the present invention.

FIG. 3 is a perspective view of a rotor blade of a turbine rotor blade according to the present invention as viewed from a fluid outflow side.

FIG. 4 is a view of another embodiment of the turbine nozzle and the turbine rotor blade according to the present invention as viewed from the circumferential direction.

FIG. 5 is a flow rate distribution chart with respect to a blade height ratio.

FIG. 6 is a loss distribution diagram with respect to a blade height ratio.

FIG. 7 is an output ratio distribution diagram with respect to a blade height ratio.

FIG. 8 is an output ratio distribution diagram for a root-side maximum point.

FIG. 9 is an output ratio distribution diagram for the local maximum on the tip side.

FIG. 10 is a diagram showing the nozzle outflow velocity decomposed into a circumferential component vector and an axial component vector.

FIG. 11 is a perspective view of a nozzle blade of a conventional turbine nozzle viewed from the fluid outflow side.

FIG. 12 is a perspective view of an inclined nozzle blade of a conventional turbine nozzle viewed from a fluid outflow side.

FIG. 13 is a perspective view of a curved nozzle blade of a conventional turbine nozzle viewed from a fluid outflow side.

[Explanation of symbols]

 10 Turbine Nozzle 11 Nozzle Blade 11a Cross Section Reference Line 12 Diaphragm Outer Ring 13 Diaphragm Inner Ring 14 Annular Flow Path 30 Turbine Moving Blade 32 Moving Blade 31 Turbine Rotor 31a Turbine Rotor Implantation Part Pa Maximum Point Pb Maximum Point Pc Minimum Point

Claims (8)

[Claims] 1. A turbine in which a plurality of nozzle blades are arranged in a row in a circumferential direction of an annular flow passage formed between an inner ring of a diaphragm and an outer ring of the diaphragm, and each nozzle blade is fixed at a joint end on the inner ring side of the diaphragm. In the nozzle, the cross section of the nozzle blade at each height position is moved in the circumferential direction, and the section reference line has one minimum point at the center of the blade height on the fluid outflow side, and between the minimum point and the blade tip and the minimum point. A turbine nozzle having features that are curved to have one local maximum between the point and the blade root. 2. A root-side maximum point of the cross-section reference line is located at a blade height ratio of 0.1 to 0.5, and a tip-side maximum point is located at a blade height ratio of 0.5 to 0.9. The turbine nozzle according to claim 1, wherein 3. A turbine rotor blade having a plurality of rotor blades arranged in a row in an implanted portion of a turbine rotor, wherein the rotor blade cross section at each height position is moved in the circumferential direction to obtain a reference line for the section. Is curved so that it has one minimum point at the blade height center on the fluid outflow side with respect to the reference radial line and one maximum point between the minimum point and the blade tip and between the minimum point and the blade root. Turbine rotor blade having the above characteristics. 4. A root-side maximum point of the cross-section reference line is located at a blade height ratio of 0.1 to 0.5, and a tip-side maximum point is located at a blade height ratio of 0.5 to 0.9. The turbine rotor blade according to claim 3, wherein 5. A turbine in which a plurality of nozzle blades are arranged in a row in a circumferential direction of an annular flow path formed between an inner ring of a diaphragm and an outer ring of the diaphragm, and each nozzle blade is fixed at a joint end on the inner ring side of the diaphragm. In the nozzle, the cross section of the nozzle blade at each height position is moved in the axial direction, and the section reference line has one minimum point at the center of the blade height on the fluid outflow side, and between the minimum point and the blade tip, and the minimum point. Between the root and the root of the wing
A turbine nozzle having features curved to have two maxima. 6. A root-side maximum point of the cross-section reference line is located at a blade height ratio of 0.1 to 0.5, and a tip-side maximum point is located at a blade height ratio of 0.5 to 0.9. The turbine nozzle according to claim 5, wherein 7. A turbine rotor blade having a plurality of rotor blades arranged in a row in an implanted portion of a turbine rotor, wherein the rotor blade cross section at each height position is moved in the axial direction to obtain a cross section reference line. Curved to have one local minimum point at the blade height center on the fluid outflow side with respect to the reference radial line and one local maximum point between the local minimum point and the blade tip and between the local minimum point and the blade root. Turbine rotor blade with features. 8. A root-side maximum point of the cross-section reference line is at a blade height ratio of 0.1 to 0.5, and a tip-side maximum point is a blade height ratio of 0.5 to 0.9. The turbine blade according to claim 7, wherein