JP3423850B2 - Axial turbine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial flow turbine, and more particularly to an axial flow turbine having a plurality of stages composed of circumferentially curved stationary vanes or moving vanes.

[0002]

2. Description of the Related Art In recent years, an axial flow turbine such as a steam turbine or a gas turbine has adopted a so-called three-dimensional design blade, which has a blade structure in which the blade is three-dimensionally curved or twisted. For example, there is a structure in which the blade trailing edge line is curved with respect to the radial line when the blade is viewed from the downstream side in the axial direction. On the other hand, when the wing is viewed from the meridian side, there is a structure that curves toward the upstream side in the axial direction. By adopting these wing structures,
Since the blade force acts in the direction normal to the blade surface and the fluid is pressed in the side wall direction, it is possible to suppress the development of the boundary layer near the side wall and the secondary flow.

As a conventional example of this three-dimensional design blade, there is one that defines a stacking method in the radial direction for a stationary blade or a moving blade alone. Although these methods can define the stacking shape of individual vanes or blades, they do not mention the difference in shape (for example, the amount of bending) when applied to other paragraphs, so that they can be applied to actual turbine components. The method of application was unknown.

[0004] Examples of those related to this type of axial turbine include JP-A-63-212704 and JP-A-8-109803.

[0005]

In the inter-blade passage of the axial turbine, a centrifugal force is generated due to the bending of the passage, and a secondary flow vortex is generated due to the imbalance between the centrifugal force and the pressure gradient. That is, in the boundary layer that develops on the upper and lower side walls between the blades, the pressure gradient in the circumferential direction predominates the centrifugal force, and a velocity component is generated in the circumferential direction to form a pair of vortices. This vortex is called a secondary flow vortex and develops around the side wall, causing fluid loss.

13 (a) and 13 (b), a short blade (wing length: H ₁ ) and a long blade (wing length: respectively) are shown.
The concept of loss distribution in the spanwise H ₂₎ is shown. In the figure, h ₁ and h ₂ are secondary flow ranges near the sidewalls corresponding to the blade lengths H ₁ and H ₂ , respectively. The distribution range of the secondary flow in the blade length direction changes depending on the development state (boundary layer thickness, turbulence degree, etc.) of the blade row inlet boundary layer and the curvature of the flow path, but roughly speaking, it is shown in the figure. The distribution range of the secondary flow does not change significantly even if the blade length changes, that is, h ₁
In many cases, ≈h ₂ is good.

[0007] For example, in the case of a steam turbine, in the flow path composed of blades used on the upstream side of a high-intermediate pressure turbine,
Compared to the flow path composed of blades used in the latter stage,
The proportion of the secondary flow region in the blade length direction is large. In the case of a blade with a short blade length that is placed on the upstream side in an axial turbine component, the maximum bending amount of the circumferentially curved shape from the radial radiation that passes through the blade root position when viewed from the axial direction, or the blade root in the meridian plane. If the maximum bending amount of the axially curved shape is not increased to a certain extent from the axial position of, the effect will not be improved against the secondary flow that has developed widely in the blade length direction.

On the other hand, in the case of a blade having a long blade length arranged on the rear stage side, the maximum bending amount of the circumferential curved shape from the radial radiation passing through the blade root position when viewed from the axial direction, or the blade root on the meridian plane If the maximum bending amount of the axially curved shape is excessively increased from the axial position of, the loss may increase if the influence of the secondary flow is small near the blade central portion.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an axial flow turbine provided with a paragraph of this type capable of effectively suppressing the development of secondary flow and boundary layer. There is.

[0010]

SUMMARY OF THE INVENTION Namely, the present invention is, in the axial-flow turbine has a plurality of stages of configured paragraph axially from curved stator vanes or rotor blades in the circumferential direction, the circumferential of the wing
The amount of bending in the direction or the axial direction is large on the front stage side and on the rear stage side.
It is formed so that it becomes smaller as it goes, and the intended purpose is achieved.

[0011]

Further, in an axial flow turbine having a plurality of stages composed of stationary blades or moving blades curved in the circumferential direction in a turbine component, the amount of circumferential or axial bending of the stationary blades or moving blades , The turbine component
Larger on the front side of the element, and smaller on the rear side.
It is formed so as to be drilled.

[0013]

That is , in the axial flow turbine thus formed, when a three-dimensional design blade curved in the circumferential direction is applied to the paragraph, a blade having a short blade length used at the front stage side has a rear stage. Compared to a blade with a long blade length used on the side, since the proportion of the secondary flow region in the blade length direction is large, by increasing the amount of bending in the former and decreasing the amount of bending according to the latter, The secondary flow and the development of the boundary layer can be effectively suppressed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic diagram of the main components of a typical steam turbine plant. The feed water 14 pressurized by a pump (not shown) becomes high-temperature and high-pressure heating steam in the boiler 11 and enters the inlet 16 of the high-pressure turbine component 8.

The steam that has worked in the high-pressure turbine component 8 returns from the outlet 17 to the boiler 11, is heated again, and enters the inlet 18 of the intermediate-pressure turbine component 9.
The steam that has worked in the medium pressure turbine component 9 is exhausted from the outlet 19 and enters the inlet 20 of the low pressure turbine component 10a, 10b through the connecting pipe. In the case of the double-flow exhaust low-pressure turbine component as in the present embodiment, steam is branched from the inlet 20 to the left and right, and finally the steam 15 is guided to the condenser from the turbine outlets 21a and 21b.

Reference numeral 13 in the drawing denotes a rotor connecting the turbine components to rotate the generator 12. Here, the turbine component referred to in the present invention means a high-pressure turbine,
Either a medium-pressure turbine, a low-pressure turbine, or a combination thereof.

FIGS. 2 and 4 show a stationary blade used in the turbine of the present invention, which is used at the front stage side in each component constituting the steam turbine. On the other hand, FIG. 3 and FIG. 5 show a stationary blade used in the turbine of the present invention, which is used at the rear stage side in each component constituting the steam turbine.

FIGS. 2 and 3 are views of the trailing edge line of the stationary blade when the stationary blade used in the steam turbine component of the present invention is viewed from the axial direction on the downstream side, and FIGS.
FIG. 3 is a diagram of a leading edge line and a trailing edge line of a vane used in a steam turbine component of the present invention when viewed from a meridian plane. As shown in these figures, the stator blade trailing edge line 3
Is curved in the circumferential direction so as to extend in the rotating direction 4 of the moving blade and to protrude toward the pressure surface side of the stationary blade. The vane leading edge line 5 is curved in the axial direction so as to project to the upstream side, as shown in FIGS. 4 and 5.

By adopting such a wing shape,
It is possible to suppress the development of the boundary layer and secondary flow developed on the sidewall by pressing the flow toward the sidewall near the root and tip. However, in the embodiment shown in FIG. 2 and FIG. 3, unnecessarily increasing the circumferential bending amount causes the outflow angle of the flow in the vicinity of the side wall to be deflected in the axial direction from the design point, and from the viewpoint of the outflow angle. Is not preferred.

In order to improve this, in FIG. 4 and FIG. 5, by curving only in the axial direction without curving in the circumferential direction, the side wall is developed without affecting the outflow angle at the blade outlet. Boundary layer and secondary flow development can be suppressed.
Therefore, the blade in which the circumferential direction and the axial direction are combined can effectively suppress the secondary flow while minimizing the deflection of the outflow angle.

The maximum curving amount of the circumferential curving shape from the radial radiation passing through the blade root position when viewed from the axial direction is expressed by δc1 and δc2 on the front side and the rear side, respectively, from the axial position of the blade root on the meridian plane. The maximum bending amount of the axial bending shape is
Let Δc3 and Δc4 be the front and rear stages, respectively. If the maximum amount of bending in the circumferential or axial direction is given for a given blade length, the loss increases. That is, it is necessary to give an appropriate maximum bending amount in the circumferential direction (Δc1 or Δc2 in this case) or maximum bending amount in the axial direction (Δc3 or Δc4 in this case) to the blade length.

In the present invention, as shown in FIG. 2 and FIG. 3, the maximum bending amount δC1 in the circumferential direction of a blade having a short blade length used on the front stage side and a long blade length used on the rear stage side are used. maximum bending amount .DELTA.C2 the circumferential direction of the blade, it is necessary to satisfy the .DELTA.C1> .DELTA.C2 the relationship. Meanwhile, FIG. 4 and FIG.
As shown in, the maximum bending amount δC3 in the axial direction of a blade having a short blade length used in the front stage side and the maximum bending amount δC4 in the axial direction of a blade having a long blade length used in the rear stage side are δC3> δ
It is necessary to satisfy the C4 becomes relationship.

As a result, a blade having a short blade length used in the front stage has a larger proportion of the secondary flow region in the blade length direction than a blade having a long blade length used in the rear stage. , Δc1 or δc3 is large in the former, δc2 in the latter
Alternatively, Δc4 can be reduced to effectively suppress the secondary flow and the development of the boundary layer.

FIG. 6 shows a reference example in which the vanes shown in FIGS. 2 to 5 are applied to a high pressure turbine component of an actual steam turbine. As shown, the steam exiting the boiler reaches the inlet 22 of the high pressure turbine component 34, does work in each paragraph, and is then exhausted from the outlet 23. The shaded portions 28 and 29 in the figure show a paragraph consisting of the stationary blades and the moving blades in the turbine component 34, and the front side 2
8 shows the rear side 29.

In this reference example , the front side 28 and the rear side 29 are 1
This is the case when they are not adjacent in one turbine component. According to this reference example , the vane shown in FIG. 2 or 4 is applied to the front side 28, and the vane shown in FIG. 3 or 5 is applied to the rear side 29.

Since the vanes used in the two paragraphs 28 and 29 in one turbine component as shown in FIG. 6 have a longer blade length on the rear stage side than on the front stage side, the amount of bending in the circumferential direction and the axial direction is reduced. For comparison, it is necessary to satisfy the relationship of Δc1> Δc2 or Δc3> Δc4. With the configuration as described above, it is possible to define the amount of bending in the circumferential direction or the axial direction according to the blade length distribution of the secondary flow in one turbine component.

A second embodiment according to the present invention will be described with reference to FIG. FIG. 7 shows an embodiment in which the vanes shown in FIGS. 2 to 5 are applied to a high pressure turbine component of an actual steam turbine. The flow of steam is the same as in the case of FIG. 6, and the points different from the first embodiment are the positions on the front stage side and the rear stage side. In this embodiment, the front side 30 and the rear side 31 are continuous. The hatched portions 30 and 31 in the figure show a paragraph consisting of the stationary blades and the moving blades in the turbine component 35, and represent the front side 30 and the rear side 31, respectively.

According to this embodiment, the stationary blade shown in FIG. 2 or 4 is applied to the front side 30, and the stationary blade shown in FIG. 3 or 5 is applied to the rear side 31. Two consecutive paragraphs 30, 31 in one turbine component as shown in FIG.
The blade length of the stationary blade used in the inner part is longer on the rear side than on the front side.
> Δc2 or δc3> δc4 must be satisfied.
The present embodiment has the same effect as the first embodiment.

Although the first and second embodiments relate to the high pressure turbine of the steam turbine, the same effect can be obtained by applying the high pressure turbine of the steam turbine to the medium pressure turbine.
Further, if the present embodiment is applied, similar effects can be obtained not only for the steam turbine but also for other axial flow turbine components such as a gas turbine. Although FIG. 2 to FIG. 5 take the stationary blade of the axial flow turbine as an example, the same effect as this embodiment can be obtained even when applied to the moving blade. Although the blade curved in the circumferential direction and the blade curved in the axial direction are treated separately in this embodiment, the same effect as in this embodiment can be obtained by applying a blade combining these.

A reference example according to the present invention will be described with reference to FIG. FIG. 8 shows a reference example in which the vanes shown in FIGS. 2 to 5 are applied to high-pressure and intermediate-pressure turbine components of an actual steam turbine. As shown in the figure, the steam exiting the boiler 11 reaches the inlet 24 of the high-pressure turbine component 36, does work in each paragraph, is then exhausted from the outlet 25, is heated again in the boiler 11, and is the inlet of the medium-pressure turbine component 37. Enter 26.

The steam that has worked in the intermediate pressure turbine component 37 is exhausted from the outlet 27 and enters the low pressure turbine component (not shown). In this reference example , the front stage side 33 and the rear stage side 32 are divided into two turbine components. The hatched portions 32 and 33 in FIG. 8 indicate a paragraph consisting of the stationary blades and the moving blades in the respective turbine components of the high-pressure turbine component and the intermediate-pressure turbine component, respectively.

In this case, if the shorter blade length is defined as the front stage side and the longer blade length is defined as the rear stage side, the same applies as described in the first or second embodiment. That is,
The vane shown in FIG. 2 or 4 is applied to the front side 33, and the vane shown in FIG. 3 or 5 is applied to the rear side 32. Since the blade length on the rear side is longer than that on the front side, comparing the amounts of bending in the circumferential and axial directions, δc1> δc2 or δc3> δ
It is necessary to satisfy the relationship of c4. With the above-described configuration, even if the two turbine components have separate front and rear stages, as in the other embodiments, the circumferential direction or the axial direction depending on the blade length direction distribution of the secondary flow is generated. The effect is that the amount of bending can be regulated.

Although the reference example described above with reference to FIG. 8 relates to a high-pressure and intermediate-pressure turbine of a steam turbine, the same effect can be obtained by applying it to an axial-flow turbine component such as a gas turbine other than the steam turbine. Is obtained.
Although FIGS. 2 to 5 show the stationary blade of the axial flow turbine as an example , the same effect as that of the present reference example can be obtained by applying it to the moving blade. Ginseng
Although blades curved in the circumferential direction curved blades axially Reference Example was treated separately, the ginseng be applied a combination of these wings
The same effect as the case can be obtained.

A third embodiment according to the present invention is shown in FIGS.
2 will be described. 9 and 11 show a vane used in the present invention, which is used at the front stage side in each component constituting the steam turbine. On the other hand, FIG. 10 and FIG. 12 show a stationary blade used in the present invention, which is used at the rear stage side in each component constituting the steam turbine.

FIG. 9 and FIG. 10 are views of the trailing edge line of the vane when the vane used in the steam turbine component of the present invention is viewed from the axial direction on the downstream side. On the other hand, FIG. 11 and FIG. 12 are views of the leading edge line and the trailing edge line of the vane when the vane used in the steam turbine component of the present invention is viewed from the meridian plane.

In the embodiment using FIGS. 2 to 5, it has been already described that the flow can be pressed toward the side wall in the vicinity of the root and the tip to suppress the development of the boundary layer developed on the side wall and the secondary flow. When the influence of the secondary flow was small in the vicinity of the blade central part, the loss tended to increase somewhat.

In order to improve this, in this embodiment, as shown in FIGS. 9 and 10, the stationary blade trailing edge line 3 is curved in the circumferential direction only in the vicinity of the upper and lower side walls so as to face the rotating direction 4 of the moving blade. The shape is such that the other portions sandwiching the central portion of the wing length have a linear shape of at least one section. As shown in FIG. 11 and FIG. 12, only the vicinity of the upper and lower side walls is curved in the axial direction so as to project to the upstream side of the vane leading edge line 5, and the other portions sandwiching the blade length central portion are at least one section. Create a shape that has a linear shape.

By adopting such a wing shape,
It is possible to suppress the development of the boundary layer and the secondary flow developed on the side wall by pressing the flow in the direction of the side wall near the root and the tip without increasing the loss near the central part of the blade length. Here, the maximum curving amount of the circumferential curving shape from the radial radiation passing through the blade root position when viewed from the axial direction is δc5, δc6 on the front side and the rear side, respectively, from the axial position of the blade root on the meridian plane. The maximum bending amount of the axial bending shape is
On the rear side, Δc7 and Δc8, respectively.

If an excessive maximum circumferential or axial bending amount is given for a given blade length, the loss increases. That is, it is necessary to give an appropriate maximum amount of curvature in the circumferential direction (Δc5 or Δc6 in this case) or maximum amount of curvature in the axial direction (Δc7 or Δc8 in this case) to the blade length. In the present invention,
As shown in FIGS. 9 and 10, the maximum bending amount δc5 in the circumferential direction of a blade having a short blade length used in the front stage side and the maximum bending amount in the circumferential direction of a blade having a long blade length used in the rear stage side. Amount δc6
Must satisfy the relationship Δc5> Δc6.

On the other hand, as shown in FIG. 11 and FIG.
The maximum axial bending amount δc7 of a blade with a short blade length used on the front stage side and the maximum bending amount δc8 of a blade with a long blade length used on the rear stage side satisfy the relationship of δc7> δc8. Is necessary. As a result, a blade with a short blade length used in the front stage has a larger proportion of the secondary flow region in the blade length direction than a blade with a long blade length used in the rear stage. Increase δc5 or δc7, and δc6 for the latter
Alternatively, Δc8 can be reduced to effectively suppress secondary flow and boundary layer development.

Embodiments are the first and second embodiments and FIG.
Similar effects to the reference example shown in (3) can be obtained even when applied to a high-pressure turbine or a medium-pressure turbine of a steam turbine. Further, if the present embodiment is applied, similar effects can be obtained not only for the steam turbine but also for other axial flow turbine components such as a gas turbine. Although FIGS. 9 to 12 show the stationary blade of the axial flow turbine as an example, the same effect as that of the present embodiment can be obtained even when applied to the moving blade. Although the blade curved in the circumferential direction and the blade curved in the axial direction are treated separately in this embodiment, the same effect as in this embodiment can be obtained by applying a blade combining these.

As described above, in the axial flow turbine thus formed, when the three-dimensional design blade curved in the circumferential direction or the axial direction is applied to the two paragraphs in the turbine component, the front stage side In a blade with a short blade length such as that used in, the proportion of the secondary flow region occupying in the blade length direction is larger than in a blade with a long blade length used in the rear stage side, so the amount of bending is large in the former, In the latter case, the secondary flow and the development of the boundary layer can be effectively suppressed by reducing the bending amount.

At this time, since the blade length on the rear stage side is longer than that on the front stage side, the amount of bending in the circumferential direction or the axial direction needs to be larger on the front stage side. With the above-described configuration, there is an effect that the amount of bending in the circumferential direction or the axial direction according to the blade length direction distribution of the secondary flow can be defined in the turbine component.

[0045]

As described above, according to the present invention, it is possible to obtain an axial flow turbine having a paragraph in which secondary flow and boundary layer development can be effectively suppressed and a fluid loss is small. it can.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the main components of an axial turbine component of the present invention.

FIG. 2 is a diagram showing the inclination of the stationary blade when the stationary blade used in the present invention is viewed from the downstream axial direction.

FIG. 3 is a diagram showing the inclination of the stationary blade when the stationary blade used in the present invention is viewed from the axial direction on the downstream side.

FIG. 4 is a view of a vane of the present invention seen from a calf surface.

FIG. 5 is a view of a vane of the present invention seen from a calf surface.

FIG. 6 is a diagram of a turbine component shown as a reference example of the present invention.

FIG. 7 illustrates a turbine component of the present invention.

FIG. 8 is a diagram of a turbine component shown as a reference example of the present invention.

FIG. 9 is a view showing the inclination of the stationary blade when the stationary blade used in the present invention is viewed from the axial direction on the downstream side.

FIG. 10 is a diagram showing the inclination of the stationary blade when the stationary blade used in the present invention is viewed from the axial direction on the downstream side.

FIG. 11 is a view of the vane of the present invention seen from the calf surface.

FIG. 12 is a view of a vane of the present invention seen from a calf surface.

FIG. 13 is a diagram showing a comparison of loss distributions in the blade length direction.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Yasugaira 7-2-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi, Ltd. Electric Power & Electrical Development Division (72) Inventor Yoshiaki Yamazaki Omika, Hitachi-shi, Ibaraki 7-2-1, Machi, Hitachi, Ltd., Electric Power & Electrics Development Headquarters (72) Inventor, Kuniyoshi Tsubouchi 7-2-1, Omika-cho, Hitachi City, Ibaraki Hitachi, Ltd. Electric Power & Electrics Development Headquarters (72) Inventor Naoaki Shibatashi 1-1-1, Sachimachi, Hitachi City, Ibaraki Hitachi Ltd. Hitachi factory (56) Reference JP-A-8-109803 (JP, A) JP-A-3-189303 (JP, A) ) JP-A-6-173605 (JP, A) JP-A-6-81603 (JP, A) JP-A-6-193402 (JP, A) JP-A-5-256103 (JP, A) JP-A-63- 212704 (JP, A) JP 5-26004 (JP, A) JP 7-253001 (JP, A) JP 2-49902 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) F01D 1/00-11/10

Claims (3)

(57) [Claims] 1. An axial flow turbine comprising a plurality of paragraphs in which axially curved blades are juxtaposed in parallel in the axial direction, wherein the circumferential or axial curving amount of the blades is greatly increased on the upstream side toward the downstream side. An axial flow turbine characterized by being formed so that it becomes smaller as it goes. 2. An axial flow turbine comprising a plurality of stages, each comprising a stationary blade or a moving blade curved in the circumferential direction in a turbine component, wherein the amount of bending in the circumferential or axial direction of the stationary blade or the moving blade is The axial flow turbine is characterized in that it is formed such that the front stage side of the turbine component becomes large and becomes smaller toward the rear stage side. 3. The axial turbine according to claim 1, wherein the blades arranged on the front stage side have a short blade length and the blades arranged on the rear stage side have a long blade length.