JP2009036112A - Blade for rotary machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blade for a rotary machine capable of inhibiting secondary flow and preventing increase of a trailing edge loss. <P>SOLUTION: This blade is provided with a blade shape part 2 which is a blade annularly arranged around a rotary shaft line and extends in a radial direction, an end wall 3 positioned at least one side of an inside end part and an outside end part in a radial direction of a blade shape part 2, and a corner part 4 smoothly connecting the blade shape part 2 and the end wall 3. The value of curvature radius on the surface of the corner part 4 reduces toward a trailing edge 6 from a leading edge 5 of the blade shape part 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotary machine blade suitable for general turbomachines such as steam turbines and gas turbines.

Conventionally, there is a technology that reduces the stress acting on the blade root part by forming a fillet-shaped corner part that smoothly connects the blade and the end wall at the blade root part of the blade used in the blade row of a rotary machine or the like. It is known (for example, refer to Patent Document 1).
In addition to reducing the stress acting on the blade root part, this corner is known to have an effect of suppressing the secondary flow, and as the radius of the corner is increased, the effect of suppressing the secondary flow is increased. It has been known.
JP 2006-291949 A

  However, when the radius of the above-described corner portion is increased, the blockage against the flow, that is, the amount of flow shielding by the blade is increased, and the flow velocity deficit on the downstream side of the blade is increased. Such an increase in the end wall blockage has the same effect as an increase in the thickness of the end wall boundary layer, which may reduce the performance of the blade disposed downstream, in other words, on the downstream side. There was a risk that the secondary loss in the arranged cascade would increase.

  Furthermore, in the portion close to the corner portion of the blade, that is, the portion close to the end wall, the same effect as that in which the trailing edge thickness of the two-dimensional blade shape is increased is expected by providing the corner portion. That is, in the blade provided with the corner portion, the trailing edge loss may increase.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a rotating machine blade capable of suppressing a secondary flow and preventing an increase in trailing edge loss. .

In order to achieve the above object, the present invention provides the following means.
The blades of the rotary machine of the present invention are blades arranged in an annular shape around the rotation axis, the blade shape portion extending in the radial direction, and the fluid flowing therearound, and the radially inner end portion of the blade shape portion And an end wall located at at least one of the outer end portions, and a corner portion that smoothly connects the blade shape portion and the end wall, and the value of the radius of curvature at the surface of the corner portion is It is characterized by decreasing from the leading edge to the trailing edge of the wing shape portion.

According to the present invention, since the value of the radius of curvature at the corner portion decreases from the leading edge toward the trailing edge, a corner portion having a larger radius of curvature than the trailing edge side is provided on the leading edge side of the wing shape portion. As a result, the formation of a secondary flow around the wing is suppressed.
On the other hand, since the corner portion having a smaller radius of curvature than the front edge side is provided on the trailing edge side, an increase in trailing edge loss is prevented.

  In the above invention, the value of the radius of curvature of the corner portion at the leading edge is a value within the range of about 1.5 to about 4 times the value of the radius of curvature of the corner portion at the trailing edge. It is desirable to be.

According to the present invention, the value of the radius of curvature of the corner portion at the leading edge is set to a value within the range of about 1.5 to about 4 times the radius of curvature of the corner portion at the trailing edge. The formation of the next flow can be more reliably suppressed, and the increase in the size of the corner portion can be suppressed, whereby the increase in the size of the blade can be suppressed.
Further, the value of the radius of curvature of the corner portion at the leading edge is more preferably a value within a range of about 2 to about 3 times the value of the radius of curvature of the corner portion at the trailing edge. By setting it as such a value, while forming a secondary flow more reliably, it can suppress the enlargement of a wing | blade.

  In the above invention, in the concave curved surface in the wing shape portion, the value of the radius of curvature of the corner portion decreases from the front edge toward the rear edge, and in the convex curved surface in the wing shape portion, the front edge From the convex side intermediate part to the convex intermediate part where the distance between adjacent wing-shaped parts is the narrowest, and the curvature of the corner part decreases from the convex intermediate part to the trailing edge. It is desirable that the value of the radius is substantially constant.

According to the present invention, the value of the radius of curvature of the corner portion on the convex curved surface is substantially constant between the convex side intermediate portion and the rear edge, so that the distance between the convex side intermediate portion and the rear edge is constant. Disturbance of fluid flow is suppressed. The region from the convex intermediate portion to the trailing edge is an open region, unlike the region from the leading edge to the convex intermediate portion facing the adjacent wing-shaped portion. Since the radius of curvature of the corner in this region affects the trailing edge loss, the value of the radius of curvature is made substantially constant from the convex middle part to the trailing edge to prevent the trailing edge loss from increasing. Is done.
On the other hand, since the value of the radius of curvature of the corner portion on the convex curved surface is reduced from the leading edge to the convex intermediate portion, the formation of secondary flow around the blade is suppressed.

  In the above invention, the position of the convex intermediate portion on the convex curved surface moves to the leading edge side or the trailing edge side based on the interval between the convex curved surface and the adjacent wing shape portion, and the convex shape The value of the radius of curvature of the corner portion on the curved surface is such that the value of the radius of curvature of the corner portion decreases from the front edge toward the position of the convex middle portion closest to the front edge, It is desirable that the value of the radius of curvature of the corner portion is substantially constant from the convex intermediate portion approaching to the rear edge.

  According to the present invention, when the interval between the convex curved surface and the adjacent wing shape portion is set to the minimum interval of the design allowable range, for example, the convex intermediate portion moves to the position closest to the front edge. Even in such a case, the value of the radius of curvature related to the corner portion is substantially constant from the value of the radius of curvature related to the corner portion of the trailing edge from the convex intermediate portion closest to the leading edge to the trailing edge. And an increase in trailing edge loss is prevented.

  On the other hand, when the distance between the convex curved surface and the adjacent blade-shaped part is wider than the above-mentioned minimum distance, the convex intermediate part moves to the trailing edge side. Here, the value of the radius of curvature according to the corner portion is the value of the radius of curvature according to the corner portion of the trailing edge from the convex intermediate portion closest to the leading edge to the trailing edge. Even if the distance from the wing-shaped part to be increased from the minimum distance, the value of the radius of curvature related to the corner part is always the value of the radius of curvature related to the corner part of the trailing edge from the convex intermediate part to the trailing edge. It can be made substantially constant, and an increase in trailing edge loss is prevented.

  In the above invention, it is desirable that the value of the radius of curvature of the corner portion monotonously decreases from the front edge toward the rear edge on the concave curved surface and the convex curved surface in the wing shape portion.

  According to the present invention, for example, when the blades of the present invention are applied to various rotating machines, the blades are rotated around an axis along the radial direction in order to exert the performance of the blades in each rotating machine. By disposing, even if the position of the convex intermediate portion moves to the front edge side or the rear edge side, the value of the radius of curvature of the corner portion continues to decrease from the front edge toward the convex intermediate portion after the angle change. Therefore, in the blade of the present invention, even if the position of the convex intermediate portion moves to the front edge side or the rear edge side, the formation of the secondary flow around the blade can be suppressed without changing the blade to be used.

  In the said invention, it is desirable that the rate of change of the value of the radius of curvature at the corner portion is continuous.

  According to the present invention, the value of the radius of curvature at the corner changes continuously and smoothly, so that the fluid flow in the vicinity of the corner is less likely to be disturbed than when the value of the radius of curvature is discontinuous. Therefore, the trailing edge loss is prevented from increasing in the blade of the present invention.

  According to the blade of the rotating machine of the present invention, a corner portion having a larger radius of curvature than the trailing edge side is provided on the leading edge side in the blade shape portion, and the formation of a secondary flow around the blade is suppressed. There is an effect that. On the other hand, since the corner portion having a smaller radius of curvature than the front edge side is provided on the trailing edge side, an effect of preventing an increase in trailing edge loss is achieved.

[First Embodiment]
The wing according to the first embodiment of the present invention will be described below with reference to FIGS.
In this embodiment, the blade of the present invention is applied to a turbine blade used in a turbomachine (rotary machine) such as a steam turbine or a gas turbine. However, the blade is not limited to the turbine blade, and is applied to a compressor blade. There is no particular limitation.
FIG. 1 is a cross-sectional view for explaining the outline of a turbine blade according to the present embodiment.

As shown in FIG. 1, the turbine blade (blade) 1 is a blade that forms a cascade of blades arranged in a ring around a rotation axis (not shown) of a turbomachine (rotary machine). As a blade used for at least one of a rotating blade and a non-rotating stationary blade.
The turbine blade 1 includes a blade-shaped portion 2 having a blade-shaped cross section extending in the radial direction, and an end wall 3 positioned at least one of the radially inner end and the outer end of the blade-shaped portion 2. A corner portion 4 that smoothly connects the wing shape portion 2 and the end wall 3 is provided.
In FIG. 1, the corner portion 4 is indicated by a contour line indicating the height from the end wall 3.

The wing-shaped part 2 is a part in which a fluid such as air flows, and in this embodiment, a rotational driving force is generated from the fluid flow. On the other hand, when the blade of the present invention is used as a compressor blade, the fluid flow is compressed by being driven to rotate.
The blade-shaped portion 2 includes a leading edge 5 located on the most upstream side with respect to the fluid flow, a trailing edge 6 located on the most downstream side, and a spine that is a curved surface curved in a convex shape connecting the leading edge 5 and the trailing edge 6. A side surface (convex curved surface) 7 and a ventral side surface (concave curved surface) 8 which is a curved surface curved in a concave shape are provided.

  Between the blade shape portions 2 of the turbine blade 1 forming the blade row is a flow path 9 (passage) through which fluid flows, and the flow path cross-sectional area of the flow path 9 gradually becomes narrower from the upstream side toward the downstream side. ing. The throat having the narrowest channel cross-sectional area of the channel 9 is formed between the back side surface 7 of the wing-shaped portion 2 and the trailing edge 6 of the adjacent wing-shaped portion 2. Here, the position of the back side surface 7 that forms the throat together with the trailing edge 6 of the adjacent wing-shaped portion 2 is referred to as a throat position (convex side intermediate portion) 10. In other words, the throat position 10 is specified as a position on the back side surface 7 that is closest to the rear edge 6 of the adjacent wing-shaped portion 2 and faces the rear edge 6.

  The end wall 3 is a wall surface extending in a direction substantially perpendicular to the blade-shaped portion 2, in other words, in the circumferential direction, and forms a part of the wall surface constituting the fluid flow path that flows between the turbine blades 1. is there. The end wall 3 is provided on at least one of the radially inner end and the outer end of the wing-shaped portion 2. In other words, the end wall 3 is provided at least at the hub side end portion in the wing-shaped portion 2, and may be provided at the tip side end portion in some cases, and is not particularly limited.

FIG. 2 is a graph for explaining a change in the radius of curvature at the corner of FIG.
The corner portion 4 is a built-up portion that is provided between the wing shape portion 2 and the end wall 3 and has a surface that smoothly connects the wing shape portion 2 and the end wall 3.
The surface of the corner portion 4 is formed in a curved surface that is curved in a concave shape with a predetermined radius of curvature in a cross-sectional view cut along a surface extending along the radial direction. As shown in FIGS. 1 and 2, the value of the radius of curvature according to the corner portion 4 is the largest value R1 of the radius of curvature according to the corner portion 4 at the leading edge 5, and the radius of curvature according to the corner portion 4 at the trailing edge 6. Value R2 is the smallest.
The radius of curvature value R1 is preferably a value in the range of about 1.5 times to about 4 times the radius of curvature value R2, and more preferably a value in the range of about 2 times to about 3 times. It is more preferable that

As shown in FIG. 2, the value of the curvature radius of the corner portion 4 on the ventral side surface 8 of the wing-shaped portion 2 is from the leading edge 5 toward the trailing edge 6 and from the curvature radius value R1 of the leading edge 5 to the trailing edge. It decreases monotonously to the radius of curvature value R2.
On the other hand, the value of the radius of curvature of the corner portion 4 on the back side surface 7 monotonously decreases from the value R1 of the curvature radius at the leading edge 5 to the value R2 of the curvature radius at the trailing edge from the leading edge 5 toward the throat position 10. Thereafter, the value R2 is substantially constant from the throat position 10 to the trailing edge 6.

Next, the effect | action in the turbine blade 1 which consists of said structure is demonstrated.
The fluid flow that has flowed into the blade row composed of the turbine blades 1 according to the present embodiment from the front edge 5 side flows into the flow path 9 between the blade rows, and flows around the blade shape portion 2 toward the rear edge 6 side. .

In the first half of the flow path 9, that is, in the vicinity of the front edge 5, the radius of curvature of the corner portion 4 is large (R1).
After that, the middle of the flow path 9 between the front edge 5 and the throat position 10 (when viewed from the back side surface 7) or between the front edge 5 and the rear edge 6 (when viewed from the ventral side surface 8). In the region, the value of the radius of curvature related to the corner portion 4 monotonously decreases, so that the fluid flow along the blade shape portion 2 is not easily disturbed.

  In the region from the throat position 10 to the rear edge 6 (uncovered region) on the back side surface 7, in other words, in the region facing the open space that does not form the flow path 9 between the adjacent wing-shaped portions 2, the corner portion Since the value of the radius of curvature of 4 does not change, the fluid flow along this region is unlikely to be disturbed. Furthermore, since the value of the radius of curvature related to the corner portion 4 in this region is substantially the same as the value of the radius of curvature R2 related to the corner portion 4 of the trailing edge 6, the flow velocity deficit formed on the downstream side of the blade-shaped portion 2 Is prevented from expanding.

Next, the effect of reducing energy loss in the turbine blade 1 according to the present embodiment will be described.
FIG. 3 is a graph illustrating energy loss in the turbine blade of FIG. In FIG. 3, the horizontal axis represents blade height, and the vertical axis represents energy loss.
The blade height on the horizontal axis is represented by 0% and 100% at both ends with reference to the radial length of the turbine blade 1. The energy loss on the vertical axis is expressed as dimensionless with reference to the energy loss at a blade height of 50%.

  The energy loss in the turbine blade 1 of the present embodiment is represented by a solid line graph in FIG. On the other hand, the energy loss in the turbine blade not provided with the corner portion 4 is represented by a dotted line graph in FIG. Furthermore, the energy loss in the turbine blade in which the value of the radius of curvature related to the corner portion 4 is constant over the entire circumference of the blade shape portion is represented by a one-dot chain line graph in FIG.

The energy loss described here is obtained by the following equation.
(Energy loss) = (total inlet pressure-total outlet pressure) / (total outlet pressure-static outlet pressure)
The inlet total pressure is the total pressure of the fluid flow upstream of the turbine blade 1, the outlet total pressure is the total pressure of the fluid flow downstream of the turbine blade 1, and the outlet static pressure is the fluid downstream of the turbine blade 1. The static pressure of the flow.

As can be seen from FIG. 3, in the turbine blade without the corner portion 4, the secondary loss SL due to the secondary flow occurs when the blade height is 10% and 90%. Further, in the turbine blade having a constant radius of curvature according to the corner 4, the secondary loss is reduced, but the energy loss in the vicinity of the end wall 3, that is, in the vicinity of the blade height of 0% and 100%. It has increased.
On the other hand, in the turbine blade of the present embodiment, it is shown that generation of the secondary loss SL is suppressed and energy loss in the vicinity of the end wall 3 is also suppressed.

According to the above configuration, the value of the radius of curvature in the corner portion 4 decreases from the leading edge 5 toward the trailing edge 6, so that the leading edge 5 side in the wing shape portion 2 is compared with the trailing edge 6 side. Therefore, the corner portion 4 having a large curvature radius is provided, and the formation of the secondary flow around the turbine blade 1 is suppressed.
On the other hand, since the corner portion 4 having a smaller radius of curvature than the front edge 5 side is provided on the trailing edge 6 side, an increase in trailing edge loss is prevented.

By setting the value R1 of the radius of curvature of the corner 4 at the leading edge 5 to a value within the range of about 1.5 to about 4 times the value R2 of the radius of curvature of the corner 4 at the trailing edge 6. Further, the formation of the secondary flow can be more reliably suppressed, and the increase in size of the turbine blade 1 can be suppressed by suppressing the increase in size of the corner portion 4.
Further, the value R1 of the radius of curvature of the corner portion 4 at the leading edge 5 is a value within a range of about 2 to about 3 times the value R2 of the radius of curvature of the corner portion 4 at the trailing edge 6. More preferred. By setting it as such a value, while forming secondary flow more reliably, the enlargement of the turbine blade 1 can be suppressed.

The value of the radius of curvature of the corner portion 4 on the back side surface 7 is set to a substantially constant value R2 from the throat position 10 to the rear edge 6 so that the fluid flow between the throat position 10 and the rear edge 6 is achieved. Disturbance is suppressed. The area from the throat position 10 to the rear edge 6 is an open area, unlike the area from the front edge 5 to the throat position 10 facing the adjacent wing-shaped part 2, and the corner part 4 in this area is open. Since the radius of curvature affects the trailing edge loss, from the throat position 10 to the trailing edge 6, the value of the radius of curvature is made substantially constant at the reduced value R2, thereby preventing the trailing edge loss from increasing.
On the other hand, since the value of the radius of curvature of the corner portion 4 on the back side surface 7 is reduced from the leading edge 5 to the throat position 10, the formation of the secondary flow around the turbine blade 1 is suppressed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the turbine blade of this embodiment is the same as that of the first embodiment, but differs from the first embodiment in the radius of curvature related to the corner portion. Therefore, in this embodiment, only the curvature radius concerning a corner part is demonstrated using FIG.4 and FIG.5, and description of another component etc. is abbreviate | omitted.
FIG. 4 is a cross-sectional view illustrating the configuration of the turbine blade according to the present embodiment. FIG. 5 is a graph for explaining a change in the value of the radius of curvature in the corner portion of FIG.
In addition, about the component same as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

As shown in FIGS. 4 and 5, the value of the curvature radius of the corner portion 104 in the back side surface 7 of the blade shape portion 2 of the turbine blade (blade) 101 according to the present embodiment is changed from the leading edge 5 to the trailing edge 6. On the other hand, the radius of curvature R1 at the leading edge 5 decreases monotonously from the radius of curvature R2 at the trailing edge.
On the other hand, the value of the radius of curvature related to the corner portion 104 on the ventral side surface 8 is from the value R1 of the radius of curvature at the leading edge 5 toward the trailing edge 6 from the leading edge 5 to the trailing edge, as in the first embodiment. The value decreases monotonously to the radius of curvature R2.

Next, the effect | action in the turbine blade 101 which consists of said structure is demonstrated.
As shown in FIG. 4, the fluid flow that has flowed into the blade row composed of the turbine blades 101 according to the present embodiment from the front edge 5 side flows into the flow path 9 between the blade rows as in the first embodiment. And flows around the wing-shaped portion 2 toward the trailing edge 6 side.

In the first half of the flow path 9, that is, in the vicinity of the front edge 5, the corner portion 104 has a large radius of curvature, so that the generation of a secondary flow that is a flow roll-up is suppressed.
After that, the middle of the flow path 9 between the front edge 5 and the throat position 10 (when viewed from the back side surface 7) or between the front edge 5 and the rear edge 6 (when viewed from the ventral side surface 8). In the region, the value of the radius of curvature related to the corner portion 104 monotonously decreases, so that the fluid flow along the blade shape portion 2 is not easily disturbed.

  In the region from the throat position 10 to the rear edge 6 on the back side surface 7, the value of the radius of curvature of the corner portion 104 monotonously decreases to R2, so that the fluid flow along this region is hardly disturbed. Further, since the value of the radius of curvature related to the corner portion 104 of the trailing edge 6 is R2 as in the first embodiment, expansion of the flow velocity deficit formed on the downstream side of the blade shape portion 2 is prevented. .

  According to the above configuration, for example, when the turbine blade 101 of the present embodiment is applied to various rotating machines such as a steam turbine, the turbine blade 101 is used to exhibit the performance of the turbine blade 101 in each rotating machine. Even if the position of the throat position 10 is moved to the front edge 5 side or the rear edge 6 side and the flow path area in the throat is changed. The value of the radius of curvature of the corner portion 104 continues to decrease from the front edge 5 toward the throat position 10 after the angle change. Therefore, in the turbine blade 101 according to the present embodiment, even when the throat position 10 moves to the front edge 5 side or the rear edge 6 side, the turbine blade 101 is used without changing the turbine blade 101 to be used. The formation of the secondary flow around can be suppressed.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the turbine blade of this embodiment is the same as that of the first embodiment, but differs from the first embodiment in the radius of curvature related to the corner portion. Therefore, in this embodiment, only the curvature radius concerning a corner part is demonstrated using FIG. 6 and FIG. 7, and description of other components is abbreviate | omitted.
FIG. 6 is a cross-sectional view illustrating the configuration of the turbine blade according to the present embodiment. FIG. 7 is a graph for explaining a change in the value of the radius of curvature in the corner portion of FIG.
In addition, about the component same as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 6, the turbine blade (blade) 201 includes a blade-shaped portion 2 having a blade-shaped cross-section extending along the radial direction, and a radially inner end and an outer end of the blade-shaped portion 2. The end wall 3 located at at least one of the above, and a corner portion 204 that smoothly connects the wing-shaped portion 2 and the end wall 3 are provided.

  Here, when the turbine blade 201 of the present embodiment is applied to various rotating machines such as a steam turbine, the axis of the turbine blade 201 along the radial direction is used to exhibit the performance of the turbine blade 201 in each rotating machine. Therefore, the position of the throat where the flow path cross-sectional area of the flow path 9 is the smallest moves to the front edge 5 side or the rear edge 6 side. That is, the throat position 10 moves to the front edge 5 side or the rear edge 6 side.

  Since the rotation angle of the turbine blade 201 described above is limited to a predetermined range, the moving range of the throat position 10 is also limited to a predetermined range. Specifically, when the turbine blade 201 is rotated and arranged in a direction in which the flow path area of the flow path 9 in the throat becomes smaller, the throat position 10 moves to the front edge 5 side. Here, a position where the throat position 10 is closest to the front edge 5 is defined as a throat position 10F.

As shown in FIG. 7, the value of the curvature radius of the corner portion 204 on the back side surface 7 of the wing-shaped portion 2 is from the curvature radius value R1 of the leading edge 5 toward the throat position 10F from the leading edge 5 to the trailing edge. It decreases monotonously to the radius of curvature value R2 at, and then becomes substantially constant at the value R2 from the throat position 10F to the trailing edge 6 via the throat position 10.
On the other hand, the value of the curvature radius of the corner portion 204 on the ventral side surface 8 decreases monotonously from the front edge 5 toward the rear edge 6 from the curvature radius value R1 at the front edge 5 to the curvature radius value R2 at the rear edge. is doing.

Next, the effect | action in the turbine blade 201 which consists of said structure is demonstrated.
The fluid flow that has flowed into the blade row comprising the turbine blades 201 according to the present embodiment from the front edge 5 side flows into the flow path 9 between the blade rows, and flows around the blade shape portion 2 toward the rear edge 6 side. .
In the first half of the flow path 9, that is, in the vicinity of the front edge 5, the radius of curvature of the corner portion 204 is large (R1).

  When the throat in the flow path 9 is formed at the throat position 10, the value of the radius of curvature related to the corner portion 204 between the front edge 5 and the throat position 10 in the flow path 9 (as viewed from the back side surface 7). Decreases monotonically from the leading edge 5 to the throat position 10F, and has a substantially constant value R2 from the throat position 10F to the throat position 10. Further, the radius of curvature of the corner portion 204 between the throat position 10 and the trailing edge 6 is substantially the same at R2.

  On the other hand, when the throat in the flow path 9 is formed at the throat position 10F, the radius of curvature of the corner portion 204 between the front edge 5 and the throat position 10F in the flow path 9 (as viewed from the back side surface 7). The value decreases monotonically from the leading edge 5 to the throat position 10F. Further, the value of the radius of curvature of the corner portion 204 from the throat position 10F to the trailing edge 6 via the throat position 10 is substantially the same at R2.

  According to said structure, when the space | interval of the back side surface 7 and the adjacent wing | blade shape part 2 is made into the minimum space | interval of a design allowable range, for example, the throat position 10 is a throat which is a position closest to the front edge 5. Move to position 10F. Even in such a case, from the throat position 10F closest to the leading edge 5 to the trailing edge 6, the value of the curvature radius according to the corner portion 204 is the value of the curvature radius according to the corner portion 204 at the trailing edge. R2 can be substantially constant, and an increase in trailing edge loss is prevented.

  On the other hand, when the distance between the back side surface 7 and the adjacent wing shape portion 2 is wider than the above-described minimum distance, the throat position 10 moves to the trailing edge 6 side. Here, the value of the radius of curvature according to the corner portion 204 is the value R2 of the radius of curvature according to the corner portion 204 of the trailing edge 6 from the throat position 10F closest to the leading edge 5 to the trailing edge 6. Even if the distance between the back side surface 7 and the adjacent wing-shaped portion 2 is increased from the minimum distance, the radius of curvature of the corner portion 204 is always set to the corner of the trailing edge 6 from the throat position 10 to the trailing edge 6. The curvature radius value R2 of the portion 204 can be made substantially constant, and an increase in trailing edge loss is prevented.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the turbine blade of this embodiment is the same as that of the first embodiment, but differs from the first embodiment in the radius of curvature related to the corner portion. Therefore, in this embodiment, only the curvature radius concerning a corner part is demonstrated using FIG. 8 and FIG. 9, and description of other components etc. is abbreviate | omitted.
FIG. 8 is a cross-sectional view illustrating the configuration of the turbine blade according to the present embodiment. FIG. 9 is a graph for explaining a change in the value of the radius of curvature in the corner portion of FIG.
In addition, about the component same as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 8, the turbine blade (blade) 301 includes a blade-shaped portion 2 having a blade-shaped cross section extending in the radial direction, and a radially inner end and an outer end of the blade-shaped portion 2. And an end wall 3 located at least one of the wing shape portion 2 and a corner portion 304 that smoothly connects the wing-shaped portion 2 and the end wall 3.

As shown in FIG. 9, the value of the curvature radius of the corner portion 304 on the back side surface 7 of the wing-shaped portion 2 is from the curvature radius value R1 of the leading edge 5 toward the throat position 10 from the leading edge 5 to the trailing edge. In other words, the rate of change in the value of the radius of curvature continuously decreases until the value R2 of the radius of curvature in FIG. Specifically, the change rate of the value of the radius of curvature is small in the region near the leading edge 5 and the throat position 10, and the value of the radius of curvature is large in the middle between the leading edge 5 and the throat position 10.
Thereafter, the radius of curvature from the throat position 10 to the trailing edge 6 is substantially constant at R2.

  On the other hand, the value of the radius of curvature related to the corner 304 on the ventral side surface 8 is also continuously from the leading edge 5 toward the trailing edge 6 from the curvature radius value R1 at the leading edge 5 to the curvature radius value R2 at the trailing edge. It is decreasing. Specifically, the change rate of the value of the radius of curvature is small in the region near the leading edge 5 and the trailing edge 6, and the value of the curvature radius is large in the middle between the leading edge 5 and the trailing edge 6.

Next, the effect | action in the turbine blade 301 which consists of said structure is demonstrated.
The fluid flow that has flowed into the blade row composed of the turbine blades 301 according to the present embodiment from the front edge 5 side flows into the flow path 9 between the blade rows, and flows around the blade shape portion 2 toward the rear edge 6 side. .

Since the value of the radius of curvature of the corner portion 304 in the vicinity of the front edge 5 is smoothly reduced from the value R1 as the distance from the front edge 5 increases, the fluid flow is smaller than that in the first embodiment described above. Hard to be disturbed.
Similarly, the value of the radius of curvature of the corner portion 304 in the vicinity of the throat portion 10 is smoothly reduced to the value R2 as it approaches the corner portion 304 from the front edge 5 side. Compared to, the fluid flow is less disturbed.

  According to the above configuration, the value of the radius of curvature in the corner 304 changes continuously and smoothly, so that the fluid flow in the vicinity of the corner 304, particularly the leading edge, compared to the case where the value of the radius of curvature is discontinuous. 5 and the fluid flow at the throat position 10 are less likely to be disturbed. Therefore, the turbine blade 301 of this embodiment can prevent an increase in trailing edge loss.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the present invention is applied to the steam turbine. However, the present invention is not limited to the steam turbine, and can be applied to general turbo machines such as a gas turbine. .

It is sectional drawing explaining the outline of the turbine blade which concerns on the 1st Embodiment of this invention. It is a graph explaining the change of the curvature radius in the corner part of FIG. It is a graph explaining the energy loss in the turbine blade of FIG. It is a graph explaining the structure of the turbine blade which concerns on the 2nd Embodiment of this invention. It is a graph explaining the change of the value of the curvature radius in the corner part of FIG. It is sectional drawing explaining the structure of the turbine blade which concerns on the 3rd Embodiment of this invention. It is a graph explaining the change of the value of the curvature radius in the corner part of FIG. It is sectional drawing explaining the structure of the turbine blade which concerns on the 4th Embodiment of this invention. It is a graph explaining the change of the value of the curvature radius in the corner part of FIG.

Explanation of symbols

1, 101, 201, 301 Turbine blade (blade)
2 Wing shape part 3 End wall 4, 104, 204, 304 Corner part 5 Front edge 6 Rear edge 7 Back side surface (convex curved surface)
8 ventral side (concave curved surface)
10 Throat position (convex middle part)

Claims (6)

A wing arranged annularly around a rotation axis,
A wing-shaped portion that extends in the radial direction and in which a fluid flows,
An end wall located at least one of the radially inner end and the outer end of the wing-shaped portion;
A corner portion that smoothly connects the wing shape portion and the end wall; and
A blade of a rotating machine, wherein a value of a radius of curvature at a surface of the corner portion decreases from a leading edge to a trailing edge of the blade shape portion.   The value of the radius of curvature of the corner portion at the leading edge is a value within a range of about 1.5 to about 4 times the value of the radius of curvature of the corner portion at the trailing edge. The rotary machine blade according to claim 1. In the concave curved surface in the wing-shaped part, the value of the radius of curvature of the corner part decreases from the leading edge toward the trailing edge,
In the convex curved surface in the wing shape portion, the value of the radius of curvature of the corner portion decreases from the leading edge toward the convex intermediate portion where the interval between adjacent wing shape portions is the smallest,
The blade of the rotating machine according to claim 1 or 2, wherein a value of a radius of curvature of the corner portion is substantially constant from the convex intermediate portion to the trailing edge. The position of the convex side intermediate portion in the convex curved surface moves to the leading edge side or the trailing edge side based on the interval between the convex curved surface and the adjacent wing shape portion,
The value of the radius of curvature of the corner portion on the convex curved surface decreases from the front edge toward the position of the convex intermediate portion closest to the front edge, and the value of the radius of curvature of the corner portion decreases.
The blade of the rotating machine according to claim 3, wherein a value of a radius of curvature of the corner portion is substantially constant from the convex intermediate portion closest to the front edge to the rear edge.   3. The value of the radius of curvature of the corner portion monotonously decreases from the front edge toward the rear edge in the concave curved surface and the convex curved surface in the wing shape portion. Rotating machine wings.   The blade of the rotating machine according to any one of claims 1 to 5, wherein a rate of change of a value of a radius of curvature in the corner portion is continuous.

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