JP5881355B2 - Stator blades and steam turbines - Google Patents

Description

  The present invention relates to a stationary blade used in a steam turbine, and a steam turbine including the stationary blade.

In recent years, a steam turbine including a stationary blade having a hollow structure in order to reduce weight has been known.
In addition, in order to improve the performance of the stationary blade, a technology has been proposed in which a slit is provided to communicate the interior and exterior of the stationary blade, and water droplets attached to the surface of the stationary blade are taken in and removed (for example, Patent Document 1). The water thus taken into the interior is discharged toward the shroud connected to the stationary blade and discharged.

Depending on the outer shape (geometric shape) and mass of the steam blades of such a steam turbine, the environment around the stator blades during turbine operation (for example, the flow velocity and mass of the steam passing through the stator blades) Self-excited vibration (flutter) may occur. In particular, it is known that self-excited vibration is likely to occur when the mass of the stationary blade is small or when the blade height is long.
Furthermore, a stationary blade having a hollow structure inside (hereinafter referred to as “hollow stationary blade”) is lighter than a stationary blade having a solid structure inside (hereinafter referred to as “solid stationary blade”). It becomes. Therefore, since the self-excited vibration is more likely to occur in the hollow stationary blade than in the solid stationary blade, it is necessary to suppress this.

  In order to suppress such self-excited vibration, a technique for attenuating vibration generated in the stationary blade by providing a damping mechanism (damper) inside the hollow stationary blade has been proposed (for example, see Patent Document 2). .

  FIG. 7 shows an example of a stationary blade provided with such a damping structure. FIG. 7A is a cross-sectional view of the main part of the stationary blade, and FIG. 7B is a side view of the main part of the stationary blade. is there.

  In the figure, the stationary blade 1 has a ventral member 2 mainly constituting the ventral side and a dorsal member 3 mainly constituting the dorsal side. The abdominal member 2 and the dorsal member 3 are each configured by bending a metal plate-like member, and both edges thereof are joined to each other by welding. The abdomen side member 2 is warped so that the surface side becomes the abdomen surface 4 of the stationary blade 1. Further, the back member 3 is warped so that the surface side is the back surface 5 of the stationary blade 1. Further, the abdominal member 2 and the back member 3 have a hollow structure by making their warpage different, and a cavity 6 is formed in the interior.

  The hollow portion 6 is provided with an arcuate leaf spring 7 which is welded and fixed to the back surface 2a of the ventral member 2 with the central portion as a base portion 7a. In addition, the hollow portion 6 is formed by, for example, slits 2 b and 2 c formed in the ventral member 2 so that the inside (cavity portion 6) and the outside of the stationary blade 1 communicate with each other, and water droplets attached to the surface of the stationary blade 1 are removed. It is taken in and removed.

  The arcuate leaf spring 7 is formed with inclined connection portions 7d and 7e from the base portion 7a to the end portions 7b and 7c toward the back side member 3 from the abdominal side member 2, and the end portions 7b and 7c are connected to the back side member 3. It is made to contact | abut to the back surface 3c.

Japanese Patent Laid-Open No. 11-336503 JP 2008-133825 A

  By the way, in the stationary blade 1 using the arched leaf spring 7 as described above, the central portion of the arched leaf spring 7 is the base portion 7a, and both ends thereof are in contact with the back surface 3c of the back side member 3. Therefore, the spring pressure is set so as to be applied to both the steam inlet side (indicated by the arrow Q) of the stationary blade 1 and the outlet side. The steam inlet side is the upstream side of the stationary blade 1 in the rectifying direction, and the steam outlet side is the downstream side of the stationary blade 1 in the rectifying direction.

  On the other hand, since the stationary blade 1 during operation of the steam turbine is in a vibration mode in which the steam outlet side is twisted, it is desirable that the damper function be concentrated on the steam outlet side as much as possible.

  However, since the bow leaf spring 7 described above is in contact with the back surface 3c with substantially the same area on both the steam inlet side and the outlet side of the stationary blade 1, only a necessary damper function is provided on the steam outlet side. Cannot be sufficiently provided, and there has been a problem that sufficient damping performance cannot be obtained as a whole of the stationary blade 1. Also, if the damping function between the steam inlet side and the outlet side is unbalanced, the contact state between the both ends 7b, 7c and the back surface 3c is likely to be point contact or line contact due to generation of vibration due to insufficient damping. There was a problem that the contact area could not be secured, causing further vibration.

Moreover, in the bow-shaped leaf spring 7, since the two ends 7b and 7c are brought into contact with the back surface 3c, not only the whole leaf spring is increased in size but also the three portions including the base portion 7a of the central portion. the I backside 2a, 3 that need to surface contact occurs c coupled with, becomes a dedicated article to change the spring pressure, shape, etc. for each exterior shape and mass of the stationary blade 1, it is difficult to sharing There was also a problem that it was inferior in versatility.

  The present invention has been made in view of such problems, and can suppress self-excited vibration with a simple configuration, easily ensure its damping function, and improve versatility. It is an object of the present invention to provide a stationary vane and a steam turbine that can be used.

In order to solve the above problems, the present invention proposes the following means.
That is, the stationary blade according to the present invention, before and stationary blade body cavity is defined by the rear surface of the flank member and dorsal member to be bonded in the edge portion and trailing edge portion, said cavity in stationary blade having a dorsal plate spring member that will be positioned, a blade height direction cross section of the ventral member, a curved small curvature toward the trailing edge portion from said front edge portion, the back-side member The blade height direction cross section of the front edge portion is curved with a large curvature at the front edge portion and then curved toward the rear edge portion with a smaller curvature than the ventral member, and the edge portion on one end side of the dorsal plate spring member is The front edge portion is fixed to the back surface of the ventral member, and the other end side of the back plate spring member is from the front edge portion side to the rear edge portion rather than the center of the airfoil center line. The back plate spring portion has a sliding contact surface with the back surface of the back member. The one end and the other end of the said sliding contact surface are connected by the connecting portion for applying a pressing force to, characterized in that.
Alternatively, a stationary blade body in which a cavity is defined by the back surfaces of the ventral member and the back member joined at the front edge part and the rear edge part, and a ventral plate spring member disposed in the cavity part, The blade height direction cross section of the ventral member has a small curvature curve from the front edge portion to the rear edge portion, and the blade height direction cross section of the back side member is the front edge. After bending with a large curvature in the part, the curved part having a smaller curvature than the ventral member is formed over the rear edge part, and the edge part on the one end side of the ventral plate-like spring member is the back side member at the front edge part. The other end side of the ventral plate spring member is slidably contacted with the back surface of the ventral member from the front edge portion side to the rear edge portion rather than the center of the airfoil center line. One end side and the other end side of the ventral plate spring member , The sliding contact surface are connected by the connecting portion for applying a pressing force to, characterized in that.
Furthermore, a stationary blade body in which a cavity is defined by the back surfaces of the abdominal member and the back member joined at the front edge portion and the rear edge portion, a back plate spring member disposed in the cavity portion, and A stationary blade having a ventral plate-like spring member, wherein the blade height direction cross section of the ventral member has a small curvature from the front edge portion to the rear edge portion, and the blade height of the back member A cross section in a direction is curved with a large curvature at the front edge portion and then curved with a smaller curvature than the ventral member over the rear edge portion, and an edge on one end side of the dorsal plate spring member is the front edge In the portion, the back side member is fixed to the back surface of the abdominal side member, and the other end side of the back side plate spring member extends from the front edge portion side to the rear edge portion rather than the center of the airfoil center line. Having a sliding contact surface with the back surface, and the back plate-like bar One end side and the other end side of the net member are connected by a connection portion that applies a pressing force to the sliding contact surface, and an edge portion on one end side of the abdominal plate spring member is the front edge portion, The back surface of the ventral member is fixed to the back surface of the back member, and the other end side of the ventral plate spring member extends from the front edge portion side to the trailing edge portion rather than the center of the airfoil center line. The one end side and the other end side of the abdominal plate spring member are connected to each other by a connecting portion that applies a pressing force to the sliding contact surface.
In addition, the blade height direction cross section of the portion where the abdomen side member and the back side member of the front edge portion are joined is configured by a curve.

  According to such a configuration, the self-excited vibration can be suppressed with a simple configuration, the damping function can be easily secured, and versatility can be improved.

In the stationary blade according to the present invention, the connecting portion of the back plate-like spring member is connected to the one end side and the other end side of the back plate-like spring member from the back surface of the ventral member. It is characterized by gradually extending toward the rear edge portion side toward the back surface of the back side member .
Or the said connection part of the said belly side plate-shaped spring member goes to the said back surface of the said belly side member from the said back surface of the said back side member so that the one end side and other end side of the said belly side plate spring member may be connected. And gradually extending toward the trailing edge portion.

  According to such a configuration, the spring pressure of the plate spring member can be easily set.

Furthermore, in the stationary blade according to the present invention, the other end side of the back plate-like spring member extends along the back surface until it reaches the vicinity of the end portion of the back surface of the back member on the rear edge portion side. It is characterized by being.
Alternatively, the other end side of the abdominal plate spring member extends along the back surface to the vicinity of the end portion of the back surface of the abdominal member on the rear edge portion side.

  According to such a configuration, it is possible to easily ensure the automatic vibration suppressing effect on the downstream end of the stationary blade body, that is, on the downstream side in the rectification direction of the stationary blade body.

  The steam turbine of the present invention is characterized in that the stationary blades are arranged at predetermined intervals in the circumferential direction of the rotor shaft.

  According to such a configuration, the self-excited vibration can be suppressed with a simple configuration, the damping function can be easily secured, and versatility can be improved.

  Furthermore, in the steam turbine according to the present invention, a slit for guiding water droplets from the surface side to the inside of the cavity is formed in the stationary blade body.

  According to such a configuration, water droplets adhering to the surface of the stationary blade body can be taken into the cavity and removed.

  According to the stator blade and the steam turbine of the present invention, the self-excited vibration can be suppressed with a simple configuration, the damping function can be easily secured, and versatility can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the schematic structure of a steam turbine, which shows the steam turbine carrying the stationary blade which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external perspective view of a main part of a steam turbine according to an embodiment of the present invention, as viewed from the low-pressure final stage side. It is the enlarged view which showed the stationary blade which concerns on one Embodiment of this invention, and looked at the stationary blade from the back side. The stator blade which concerns on one Embodiment of this invention is shown, (A) is sectional drawing which shows the airfoil of a stationary blade, (B) is sectional drawing of a plate-shaped spring member. The stator blade of the modification 1 which concerns on one Embodiment of this invention is shown, (A) is sectional drawing which shows the airfoil of a stationary blade, (B) is sectional drawing of a plate-shaped spring member. It is sectional drawing which shows the stationary blade of the modification 2 which concerns on one Embodiment of this invention, and shows the airfoil of a stationary blade. A conventional stator blade is shown, (A) is a sectional view showing an airfoil shape of the stator blade, and (B) is a side view of a main part of the stator blade.

  Next, a stationary blade and a steam turbine according to an embodiment of the present invention will be described with reference to the drawings. The following examples are preferred specific examples of the stationary blades and steam turbines of the present invention, and may have various technically preferable limitations. However, the technical scope of the present invention is particularly limited to the present invention. Unless stated to limit the invention, it is not limited to these embodiments. In addition, the constituent elements in the embodiments shown below can be appropriately replaced with existing constituent elements and the like, and various variations including combinations with other existing constituent elements are possible. Therefore, the description of the embodiment described below does not limit the contents of the invention described in the claims.

  FIG. 1 is an explanatory view schematically showing a schematic configuration of a steam turbine equipped with a stationary blade according to an embodiment of the present invention, and FIG. 2 is a view of the steam turbine showing an embodiment of the present invention from the low-pressure final stage side. FIG. 3 is an enlarged perspective view of a stationary blade showing an embodiment of the present invention viewed from the back side, FIG. 4 shows the stationary blade of the present invention, and FIG. 4 (A) is a blade of the stationary blade. FIG. 4B is a cross-sectional view of a plate-like spring member.

  As shown in FIG. 1, a steam turbine 10 according to the present embodiment is a low-pressure steam turbine used in, for example, a nuclear power plant, and a steam generator 11 that generates high-pressure steam and a high-pressure from the steam generator 11. The high pressure steam turbine 12 to which the steam of the steam is directly supplied, the moisture separation heater 13 for separating and heating the steam moisture from the steam generator 11 and the high pressure steam turbine 12, and the low pressure from the moisture separation heater 13 A steam turbine 10 is provided. Hereinafter, in the present embodiment, a low-pressure steam turbine that receives supply of steam from the moisture separator 13 as the steam turbine 10 will be described.

  In the steam turbine 10, steam from the moisture separation heater 13 is supplied to the steam inlet 14, and the steam passage 15 formed in the steam turbine 10 is indicated in the axial direction of the rotor shaft 16 (indicated by an arrow A in the figure). ) To distribute. In the steam passage 15, the moving blades 17 and the stationary blades 18 are alternately arranged, and the steam turbine 10 generates kinetic energy by the pressure drop in the stationary blades 18, and this is converted into rotational torque by the moving blades 17. doing. As a result, the rotor shaft 16 coupled with the moving blade 17 rotates by the rotational torque converted by the moving blade 17.

  As shown in FIGS. 1 to 3, the stationary blade 18 has an inner end 18 a in the radial direction (indicated by an arrow R in the drawing) of the rotor shaft 16 at the shroud 19 and an outer end 18 b in the radial direction at the blade root ring 20. Are connected by welding (the welded portion is indicated by reference numeral 21 in FIG. 3).

As shown in FIG. 1, the moving blade 17 and the stationary blade 18 are paired and one step 22 is arranged as many as necessary. Further, the stage 22 is configured such that the blade heights of the moving blade 17 and the stationary blade 18 become longer as the steam passage 15 moves from the upstream side to the downstream side. The stage 22 on the most downstream side of the steam passage 15 is referred to as a “low pressure final stage”. The stationary blade 18 of the low-pressure final stage 22 has a particularly long blade height compared to the stationary blade 18 in the upstream stage 22. In the low-pressure final stage 22, a plurality of stationary blades 18 are arranged at a predetermined interval in the circumferential direction of the rotor shaft 16 (indicated by an arrow P in the figure) as shown in FIGS. Is forming.

As shown in FIG. 4A, the stationary blade 18 includes a ventral member 24 that mainly configures the ventral side, and a dorsal member 25 that mainly configures the dorsal side. The abdominal member 24 and the dorsal member 25 are made by bending metal plate-like members in different warping directions, respectively, and bending the metal plate-like members in different warping directions. By joining the vicinity of the edge along the edge by welding, an exterior shape as the stationary blade body is formed. In the present embodiment, the leading edge portion (indicated by arrow Q indicates the inflow direction of steam) located on the steam inlet side is TIG welding (reference numeral 26), and the trailing edge portion located on the steam outlet side is a laser. They are joined by welding (reference numeral 27). The abdomen side member 24 is warped so that the surface side becomes the abdomen surface 28 of the stationary blade 18. Further, the back member 25 is warped so that the surface side is the back surface 29 of the stationary blade 18. Furthermore, the abdominal member 24 and the dorsal member 25 form a hollow portion 30 with a hollow structure inside by making the curvature of the warpage different. That is, a cavity 30 extending along the blade height direction (the radial direction of the rotor shaft 16) is formed between the back surface 24c of the abdominal member 24 and the back surface 25a of the back member 25. In addition, inside the stationary blade 18, the inner surface of the blade is formed by the back surface 24 c of the abdominal member 24 and the back surface 25 a of the back member 25. The steam inlet side is the upstream side of the stationary blade 18 in the rectifying direction, and the steam outlet side is the downstream side of the stationary blade 18 in the rectifying direction.

The ventral member 24 and the back member 25 extend along the blade height direction over substantially the same length. The ventral member 24 includes a plurality of slits 24 a on the front edge side and slits 24 b on the rear edge side along the radial direction R.
The “blade height direction” is a direction perpendicular to the airfoil cross section (a cross section parallel to the axis of the rotor shaft 16) shown in FIG. The directions are orthogonal. In addition, slits substantially the same as the slits 24 a and 24 b can be formed in the back member 25. Furthermore, the shapes and lengths of the slits 24a and 24b are arbitrary.

  Thus, in the stationary blade 18 of the present embodiment, the ventral member 24 constitutes the ventral side of the cavity portion 30 of the stationary blade 18, and the back member 25 is on the back side of the cavity portion 30 of the stationary blade 18. Is configured.

  The cavity 30 formed inside the stationary blade 18 communicates with the outside of the stationary blade 18 through slits 24 a and 24 b formed in the ventral member 24. In the stationary blade 18 in which the cavity 30 and the slits 24a and 24b are formed, the water adhering to the abdominal surface 28 moves, for example, on the abdominal surface 28 under the vapor pressure, and is indicated by an arrow W in FIG. Thus, it can flow into the cavity 30 from the slits 24a and 24b.

  The water taken into the cavity 30 flows toward the shroud 19. As shown in FIG. 3, the shroud 19 is formed with an opening 31 communicating with the cavity 30 of the stationary blade 18. Water in the cavity 30 is discharged from the opening 31 as indicated by an arrow E. It is possible.

  As described above, the hollow stationary blade 18 having the hollow portion 30 inside has a relatively small natural frequency as compared with the solid stationary blade having no hollow portion 30 therein, and the operation of the steam turbine 10 At times, self-excited vibration (flutter) is likely to occur. When the self-excited vibration occurs, the stationary blade 18 is bent or twisted due to elastic deformation, and a relative position variation occurs between the abdominal member 24 and the back member 25 of the stationary blade 18.

  In order to attenuate this relative positional fluctuation, in the stationary blade 18 according to the present embodiment, a plate-like spring member 32 that can be slidably contacted from the cavity 30 to one of the blade inner surfaces (back surface 24c, back surface 25a). When the stationary blade 18 is elastically deformed, the plate-like spring member 32 is configured to generate friction with one of the blade inner surfaces (the back surface 24c and the back surface 25a).

  Specifically, the plate spring member 32 has a length along the blade height direction (hereinafter referred to as “length direction” with respect to the plate spring member 32), and extends along the airfoil center line C. It is formed from a press-formed product of a sheet metal member having a width (hereinafter referred to as “width direction” with respect to the plate spring member 32). Further, the plate-like spring member 32 is welded along the harmful length direction by using the front edge (steam inlet side) side of the edge portion along the length direction as a fixed portion 32a, thereby backside the abdominal side member 24. 24c is fixed. Further, the plate-like spring member 32 presses the back surface 25a of the back side member 25 so as to be slidable with a range extending from the vicinity of the center in the width direction to the rear edge (steam outlet side) as a pressing portion 32b. Further, the portion between the fixed portion 32a and the pressing portion 32b of the plate spring member 32 is inclined so as to extend over the back surface 24c and the back surface 25a, and constitutes a connecting portion 32c that connects the fixing portion 32a and the pressing portion 32b. As shown in FIG. 4 (B), the connecting portion 32c has an inclination angle (including the angle of the corner portion at the boundary between the connecting portion 32c and the pressing portion 32b). Has been granted. Therefore, the fixing portion 32a is brought into close contact with the back surface 24c in a predetermined length direction and width direction, and the pressing portion 32b is pressed in a close contact state with the back surface 25a in a predetermined length direction and width direction. Moreover, the pressing part 32b can be slidably contacted with the back surface 25a. Moreover, in the present embodiment, the pressing part 32b presses the back surface 25a in a range extending from the front edge side to the vicinity of the rear edge rather than the center of the airfoil center line C. Thereby, it is possible to exert a damping action for suppressing the self-excited vibration of the stationary blade 18 in a wide area on the steam outlet side of the stationary blade 18.

  In such a configuration, in a state (initial state) disposed in the cavity 30, the plate spring member 32 is bent (inclination angle of the connection portion 32 c), as shown in FIG. It is formed to be slightly elastically deformed. With this elastic force, the plate-like spring member 32 is configured such that the pressing portion 32b presses the back member 25 from the back surface 25a as shown in FIG. That is, when the plate-like spring member 32 is disposed in the hollow portion 30, the plate-like spring member 32 is configured to mainly bias the back surface 25 a of the back side member 25 outward in the blade thickness direction of the stationary blade 18.

  The “blade thickness direction” means the thickness direction of the stationary blade 18 perpendicular to the airfoil center line C in the airfoil cross section shown in FIG.

  When the steam outlet of the stationary blade 18 is mainly elastically deformed by the elastic force of the plate spring member 32, a relative position variation occurs between the back surface 24c of the ventral member 24 and the back surface 25a of the back member 25. A dynamic friction force having a magnitude corresponding to the urging force can be applied.

  During operation of the steam turbine 10, depending on the operating conditions, self-excited vibration may occur in the stationary blade 18, and the stationary blade 18 may try to elastically deform.

  At this time, the plate-like spring member 32 mainly presses in a wide range with the back surface 25a of the back side member 25, so that the dynamic frictional force is exerted in a direction that suppresses relative positional fluctuation between the abdominal side member 24 and the back side member 25. Occurs. This dynamic friction force attenuates the relative position fluctuation between the ventral member 24 and the dorsal member 25. As a result, the self-excited vibration generated in the stationary blade 18 can be suppressed.

  By the way, in the said embodiment, the plate-shaped spring member 32 joins the fixing | fixed part 32a to the back surface 24c of the abdominal side member 24 in a cantilever state, and the press part 32b is in the wide range to the back surface 25a of the side member 25. Although the structure to press is disclosed, for example, as shown in FIG. 5, the fixing portion 42 a on the front edge side of the plate spring member 42 is joined to the back surface 25 a near the steam inlet side of the back side member 25 in a cantilever state. The sliding contact portion 42b on the rear edge side of the plate-like spring member 42 is brought into contact from the vicinity of the vapor inlet side of the back surface 24c of the ventral member 24 to the vicinity of the outlet side, and the spring property (deflection) is determined by the inclination angle of the connection portion 42c. ). In addition, as shown in FIG. 6, the plate spring members 32 and the plate spring members 42 may be alternately arranged along the radial direction R (along the depth direction on the paper surface). At this time, at least one plate spring member 32 and one plate spring member 42 are used, but it is not necessary to use the same number (pair).

  Thus, in the stationary blade and the steam turbine of the present invention, the cantilevered plate-like spring members 32 and 42 are configured to mainly press the steam outlet side, and the spring pressure is set to one connecting portion 32c. , 42c can be set, and only the pressing portions 32b, 42b are formed along the back surface 25a (or the back surface 24c), thereby suppressing self-excited vibration with a simple configuration and a damping function thereof. Can be easily secured, and versatility can be improved.

DESCRIPTION OF SYMBOLS 10 ... Steam turbine 18 ... Stator blade 24 ... Ventral side member (abdominal side)
24a ... Slit 24b ... Slit 24c ... Back side 25 ... Back side member (back side part)
25a ... Back 30 ... Cavity 32 ... Plate spring member 32a ... Fixed part 32b ... Pressing part 32c ... Connecting part

Claims (10)

A stationary blade body cavity is defined by the rear surface of the flank member and dorsal material to be joined at a leading edge portion and trailing edge portion,
A dorsal plate spring member that will be disposed in the cavity,
In a stationary blade having
The blade height direction cross section of the ventral member has a small curvature curve from the leading edge portion to the trailing edge portion,
The wing height direction cross section of the dorsal member is curved with a large curvature at the front edge portion and then curved with a smaller curvature than the ventral member over the trailing edge portion,
An edge portion on one end side of the back plate-like spring member is fixed to the back surface of the ventral member at the front edge portion,
The other end side of the back plate spring member has a sliding surface with the back surface of the back member from the front edge portion side to the rear edge portion rather than the center of the airfoil center line,
The one end side and the other end side of the dorsal plate spring member are connected by a connecting portion that applies a pressing force to the sliding contact surface.
A stationary blade characterized by that. A stationary blade body cavity is defined by the rear surface of the flank member and dorsal material to be joined at a leading edge portion and trailing edge portion,
A ventral plate spring member that will be disposed in the cavity,
In a stationary blade having
The blade height direction cross section of the ventral member has a small curvature curve from the leading edge portion to the trailing edge portion,
The wing height direction cross section of the dorsal member is curved with a large curvature at the front edge portion and then curved with a smaller curvature than the ventral member over the trailing edge portion,
An edge portion on one end side of the abdominal plate spring member is fixed to the back surface of the back member at the front edge portion,
The other end side of the ventral plate spring member has a sliding surface with the back surface of the ventral member from the front edge part side to the rear edge part rather than the center of the airfoil center line,
The one end side and the other end side of the abdominal plate spring member are connected by a connecting portion that applies a pressing force to the sliding contact surface.
A stationary blade characterized by that. A stationary blade body cavity is defined by the rear surface of the flank member and dorsal material to be joined at a leading edge portion and trailing edge portion,
And the back-side plate spring member and the ventral plate spring member that will be disposed in the cavity,
In a stationary blade having
The blade height direction cross section of the ventral member has a small curvature curve from the leading edge portion to the trailing edge portion,
The wing height direction cross section of the dorsal member is curved with a large curvature at the front edge portion and then curved with a smaller curvature than the ventral member over the trailing edge portion,
An edge portion on one end side of the back plate-like spring member is fixed to the back surface of the ventral member at the front edge portion,
The other end side of the back plate spring member has a sliding surface with the back surface of the back member from the front edge portion side to the rear edge portion rather than the center of the airfoil center line,
One end side and the other end side of the dorsal plate-like spring member are connected by a connecting portion that applies a pressing force to the sliding contact surface,
An edge portion on one end side of the abdominal plate spring member is fixed to the back surface of the back member at the front edge portion,
The other end side of the ventral plate spring member has a sliding surface with the back surface of the ventral member from the front edge part side to the rear edge part rather than the center of the airfoil center line,
The one end side and the other end side of the abdominal plate spring member are connected by a connecting portion that applies a pressing force to the sliding contact surface.
A stationary blade characterized by that. The connecting portion of the back plate-like spring member gradually moves from the back surface of the ventral member toward the back surface of the back member so as to connect one end side and the other end side of the back plate spring member. vane according to claim 1 or 3, characterized in that extending the trailing edge portion side. The other end of the back-side plate spring member, according to claim 1, 3, characterized in that extending along the back surface up to the vicinity of an end portion of said trailing edge portion side of the back surface of the back-side member The stationary blade according to any one of 4 . The connecting portion of the abdominal plate spring member gradually moves from the back surface of the back member toward the back surface of the abdominal member so as to connect one end side and the other end side of the abdominal plate spring member. The stationary blade according to claim 2 , wherein the stationary blade extends toward the trailing edge portion . The other end of the belly-side plate spring member, according to claim 2, characterized in that extending along the back surface up to the vicinity of the end portion of the rear edge portion side of the back surface of the ventral side member The stationary blade according to any one of 6 and 6 . The blade height direction cross section of the portion where the ventral member and the dorsal member of the front edge portion are joined is configured with a curve.
The stationary blade according to any one of claims 1 to 7, wherein A steam turbine, wherein the stator blades according to any one of claims 1 to 8 are arranged at a predetermined interval in a circumferential direction of the rotor shaft. The steam turbine according to claim 9 , wherein a slit for guiding water droplets from the surface side to the inside of the cavity is formed in the stationary blade body.

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