JP2008133825A - Stationary blade and steam turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stationary blade and a steam turbine capable of inhibiting self-excited vibration with a simple structure. <P>SOLUTION: In the stationary blade 20, a cavity 40 extending in a blade width direction is formed, and slits 28a, 28c making the cavity 40 communicate to an outside are formed. A waveform flat spring 44 slidingly butts on at least one of a face side member 25 and a back side member 27 is provided between the face side member 25 which is a section in a face side of the cavity 40 and the back side member 27 which is a section in a back side of the cavity 40. When a stationary blade 20 elastically deforms, the waveform flat spring 44 generates friction with at least either one of the face side member 25 and the back side member 27. Relative position fluctuation between the face side member 25 and the back side member 27 is attenuated by the friction. Consequently, self-excited vibration generated on the stationary blade can be inhibited. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a stationary blade used in a steam turbine, and more particularly, to an internal structure of a stationary blade and a steam turbine having the stationary blade of the internal structure.

  In recent years, in order to reduce the weight of a steam turbine, a technique of forming a hollow structure in which a cavity is formed inside a stationary blade is known. Furthermore, in order to improve the performance, a technique has been proposed in which a slit for communicating the cavity of the stationary blade and the outside is provided, and water droplets adhering to the surface of the stationary blade are taken into the cavity and removed (for example, Patent Document 1). reference). The water taken in the cavity is discharged toward the shroud connected to the stationary blade.

  Depending on the exterior shape (geometrical shape) and mass of the steam blade of such a steam turbine, the environment around the stationary blade at the time of turbine operation (for example, the flow velocity and mass of steam passing through the stationary blade), 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 width (the entire length of the blade) is long.

  In order to suppress such self-excited vibration, a technique for attenuating vibration generated in the stationary blade by providing a damping mechanism (damper) at the joint between the stationary blade and the shroud has been proposed (for example, Patent Document 2). , 3).

Japanese Patent Laid-Open No. 11-336503 Japanese Patent No. 3461562 Japanese Patent No. 2877837

  By the way, a stationary vane having a cavity inside as described above (hereinafter referred to as a hollow stationary blade) is lighter than a solid stationary blade having no cavity inside (hereinafter referred to as a solid stationary blade). It will be a thing. Therefore, the self-excited vibration is more likely to occur in the hollow stationary blade than in the solid stationary blade, and it is necessary to suppress this.

  However, it is extremely difficult to apply the above-described damping mechanism to a steam turbine that employs a hollow stationary blade because of the design structure. For example, if an attempt is made to provide a damping mechanism as in Patent Documents 1 and 2 at the joint between the hollow stationary blade and the shroud, the damping mechanism will block the cavity that continues from the hollow stationary blade to the shroud and is taken into the cavity. There is a problem that the discharged water cannot be discharged well toward the shroud.

  Therefore, the present invention has been made in view of the above, and an object thereof is to provide a stationary blade and a steam turbine capable of suppressing self-excited vibration with a simple configuration.

  In order to achieve the above object, a stator blade according to claim 1 is a stator blade used in a steam turbine, in which a cavity is formed and a slit is formed to communicate the cavity and the outside. In addition, a sliding contact member capable of sliding contact from the cavity to the blade inner surface is provided.

  The stationary blade according to claim 2 is the stationary blade, and includes a ventral side portion that is a portion on the ventral side from the cavity and a back side portion that is a portion on the back side from the cavity, and the sliding contact member is It is provided between the ventral part and the dorsal part, and is in contact with at least one of the ventral part and the dorsal part.

  According to a third aspect of the present invention, the stationary blade is the stationary blade, and the sliding contact member is a biasing member that biases the abdominal side portion and the back side portion outward in the blade thickness direction.

  The stationary blade according to claim 4 is the stationary blade, wherein the urging member has a plate shape extending along the blade width direction, and presses the abdominal side portion and the back side portion by an elastic force due to bending. It is assumed to be a spring member.

  According to a fifth aspect of the present invention, the stationary blade is the stationary blade, wherein the plate-like spring member has a corrugated cross section, and a corrugated apex is in contact with the abdominal side and the back side.

  The stationary blade according to claim 6 is the stationary blade, wherein the plate-like spring member has a substantially C-shaped cross section, and a C-shaped open end portion is provided on one of the abdominal side portion and the back side portion. It is assumed that a C-shaped base is in contact with the other.

  The stator blade according to claim 7 is the stator blade, wherein the plate-like spring member has a bow-shaped cross section, and an arcuate end portion is in contact with either the ventral side portion or the dorsal side portion. The other side is in contact with an arcuate base.

  The stationary blade according to claim 8 is the stationary blade, wherein two plate-like spring members having a bow-shaped cross section are arranged along the blade thickness direction, and a base portion of each plate-like spring member It is assumed that the back surfaces of each other are in sliding contact with each other.

  The stator blade according to claim 9 is the stator blade, wherein an end portion of the plate-like spring member has a divided structure or a slit structure divided into a plurality of plates in the plate thickness direction. .

  The stationary blade according to claim 10 is the stationary blade, wherein the plate-like spring member has a U-shaped cross section, and a U-shaped arm portion is in contact with the abdominal side portion and the back side portion. Shall.

  The stator blade according to claim 11 is the stator blade, wherein the abdominal side portion and the back side portion are coupled to each other at the front edge portion and the rear edge portion, and the plate-like spring member is provided on the abdominal side portion. And one of the dorsal sides.

  The stationary blade according to claim 12 is the stationary blade, wherein a damping material is provided in a cavity partitioned by a plate-like spring member and not communicating with the outside through a slit. And

  A stationary blade according to a thirteenth aspect is the stationary blade, which is provided substantially orthogonal to the average warp line of the blade, and the cavity formed inside is divided into a cavity on the leading edge side and a cavity on the trailing edge side. It is assumed that a partition wall in the form of a plate is provided, and a damping material is filled in the cavity on the rear edge side.

  The steam turbine according to a fourteenth aspect is characterized in that the stationary blades are arranged at predetermined intervals in the circumferential direction of the rotor shaft.

  A steam turbine according to a fifteenth aspect is the steam turbine, in which solid stationary blades are mixedly arranged.

  The steam turbine according to a sixteenth aspect is the steam turbine, wherein the stationary blades and the solid stationary blades are alternately arranged.

  The steam turbine according to claim 17 is the steam turbine in which a plurality of types of stationary blades having different natural frequencies are arranged.

  According to the stationary blade according to claim 1, since the sliding contact member that can slide from the cavity to the blade inner surface is provided, when the stationary blade is elastically deformed, the sliding contact member slides from the cavity to the blade inner surface, Friction is generated between the blade inner surfaces. By attenuating the elastic deformation of the stationary blade by this friction, the self-excited vibration generated in the stationary blade can be suppressed.

  According to the stator blade according to claim 2, since the sliding contact member is provided between the abdominal part and the dorsal part, and is in contact with at least one of the abdominal part and the dorsal part, When the elastic deformation occurs, friction is generated between the sliding contact member and at least one of the abdomen and the dorsal side, and this friction attenuates the relative position fluctuation that occurs between the abdomen and the dorsal side. can do. Thereby, the self-excited vibration which arises in a stationary blade can be suppressed.

  According to the stationary blade according to the third aspect, since the sliding contact member is an urging member that urges the abdominal side portion and the back side portion outward in the blade thickness direction, respectively, When the relative position variation occurs, the urging member can generate a dynamic friction force having a magnitude corresponding to the urging force between at least one of the abdominal side portion and the back side portion. By selecting the rigidity of the urging member and adjusting the urging force in the state of being placed in the cavity (initial state), the attenuation characteristics of the position fluctuation between the ventral side and the dorsal side can be changed to the desired characteristics. Can be set.

  According to the stator blade according to claim 4, since the urging member is a plate-like spring member that has a plate shape and presses the abdomen and the dorsal side by the elastic force due to the bending, the rectangular plate member The urging member extending in the longitudinal direction of the plate-like spring member, that is, the blade width direction of the stationary blade can be easily realized simply by curving the plate in the width direction by press molding or the like.

  According to the stator blade according to claim 5, since the cross-sectional spring member has a wave shape, the abdomen side or the back side can be slidably contacted with a plurality of wave tops, Friction can be generated between the ventral part or the dorsal part.

  According to the stator blade according to claim 6, since the plate-like spring member has a C-shaped cross section, the plate-like spring member is in sliding contact with the abdominal side portion or the back side portion with a sufficient area. It is possible to generate friction between the ventral part or the dorsal part. A plate-like spring member can be easily realized simply by bending a flat plate-like member so as to be rounded in the width direction.

  According to the stator blade according to claim 7, since the cross section of the plate spring member has an arcuate shape, the plate spring member is in sliding contact with the ventral portion or the dorsal portion with a sufficient area. Thus, friction can be generated between the ventral part or the dorsal part. A plate-like spring member can be easily realized only by forming two gentle mountain folds and two valley folds on a flat plate-like member.

According to the stator blade according to the eighth aspect, since the friction can be generated by bringing the back surfaces of the base portions into sliding contact with each other, the end portion of the plate spring member is connected to the back by, for example, welding. Can be fixed to the side or the ventral side, so that the contact between the end and the dorsal side resulting from the dimensional tolerance of the leaf springs and the dimensional tolerance of the wings (ventral and dorsal), and It is possible to reliably prevent contact between the end portion and the ventral member.
In addition, the contact | abutting of the back surfaces of a base part can be avoided by selecting the material of a plate-shaped spring member suitably (selecting the material which back surfaces do not contact each other).

  According to the stator blade according to the ninth aspect, when the stator blade is elastically deformed, friction damping is generated between the divided plates. Thereby, the relative position fluctuation between the abdominal part and the back part can be further attenuated, and the self-excited vibration generated in the stationary blade can be further suppressed.

  According to the stator blade according to the tenth aspect, since the plate-like spring member has a U-shaped cross section, the plate-like spring member can be made compact and easy to be placed in the cavity. become. A plate-like spring member can be easily realized simply by forming two bent portions on a flat plate-like member.

  According to the stator blade according to the eleventh aspect, since the plate spring member is coupled to one of the abdominal side portion and the back side portion, the plate spring member can be fixed at a desired position of the cavity. it can. Thereby, it becomes possible to suppress the occurrence of variation in the attenuation characteristic of the position variation between the abdominal side and the back side.

  According to the stator blade of the twelfth aspect, since the vibration damping material is provided in the cavity that does not communicate with the outside through the slit, the deformation between the abdominal member and the back member is caused by the deformation resistance of the vibration damping material. Relative position fluctuations between them can be attenuated.

According to the stator blade according to the thirteenth aspect, the damping material is provided in the cavity on the rear edge side partitioned by the partition plate. By utilizing the deformation resistance of the damping material, it is possible to attenuate the relative position fluctuation between the ventral portion and the dorsal portion.
Moreover, since the damping material is filled in the cavity on the rear edge side instead of the plate spring member, from the dimensional tolerance of the leaf spring and the dimensional tolerance of the wing (abdomen side and back side) It is possible to prevent the generated leaf spring from hitting one piece.

  According to the steam turbine of the fourteenth aspect, since the stationary blades are arranged at a predetermined interval in the circumferential direction of the rotor shaft, the stationary blades are arranged in the same stage blade group as compared with the solid stationary blades. Self-excited vibration can be suppressed by arranging hollow stationary blades that are less likely to generate excited vibration (flutter).

  According to the steam turbine of the fifteenth aspect, since the solid stationary blades are mixedly arranged, the stationary blades having greatly different natural frequencies are arranged side by side without changing the exterior shape of the stationary blades. It becomes possible to arrange. As a result, it is possible to suppress self-excited vibration resulting from the fact that blades having substantially the same natural frequency are arranged adjacent to each other in the same stage blade group.

  According to the steam turbine of the sixteenth aspect, since the stationary blades and the solid stationary blades are alternately arranged, the stationary blades adjacent to each other in the same stage blade group surely have a natural frequency. Can be different. Thereby, the self-excited vibration resulting from arrange | positioning the thing with a substantially equal natural frequency adjacent can be suppressed more.

  According to the steam turbine of the seventeenth aspect, since the stationary blades having different natural frequencies are arranged, the hollow stationary blades that can take in and remove moisture adhering to the blade surface into the cavities are arranged in the same stage. As many as possible can be arranged. Thereby, while suppressing the self-excited vibration resulting from arrange | positioning the thing with a substantially equal natural frequency adjacent, the performance improvement of a steam turbine can be aimed at.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  First, the configuration of the steam turbine according to the present embodiment will be described with reference to FIGS. FIG. 1 is a diagram schematically showing a schematic configuration of the steam turbine, FIG. 2 is an external view of the steam turbine as viewed from the low-pressure final stage side, and FIG. 3 is a back view of the stationary blade shown in FIG. It is the enlarged view seen from the side.

  The steam turbine according to the present embodiment is used in a nuclear power plant or the like, and in such a plant, as shown in FIG. 1, a steam generator 3 that generates high-pressure steam, and a steam generator 3 A high-pressure steam turbine 5 to which high-pressure steam is directly supplied from the steam generator, a moisture separator heater 7 for separating and heating the steam moisture from the steam generator 3 and the high-pressure steam turbine 5, and a moisture separator heater 7 A low-pressure steam turbine 1 to which low-pressure steam is supplied from is provided. In this embodiment, as an example, a low-pressure steam turbine 1 that receives supply of steam from a moisture separator heater 7 will be described.

  In the steam turbine 1, the steam from the moisture separation heater 7 is supplied to the steam inlet 10, and the steam passage 12 formed in the steam turbine 1 is indicated by the axial direction of the rotor shaft 14 (indicated by an arrow A in the figure). ) Flow along. In the steam passage 12, the moving blades 16 and the stationary blades 20 are alternately arranged, and the steam turbine 1 generates kinetic energy due to a pressure drop in the stationary blades 20, and this is converted into rotational torque by the moving blades 16. is doing.

  The rotor blade 16 is coupled to the rotor shaft 14 and rotationally drives it. On the other hand, as shown in FIGS. 1 to 3, the stationary blade 20 has an inner end 22 a in the radial direction (indicated by an arrow R) of the rotor shaft 14 at the shroud 30 and an outer end 22 c in the radial direction at the blade root. Each ring 32 is joined by welding (the welded portion is indicated by reference numeral 34 in FIG. 3).

  As shown in FIG. 1, the moving blade 16 and the stationary blade 20 constitute a pair of “stages”, and the steam turbine 1 includes a large number of stages 18, 18 a,. Is provided. These stages 18, 18 a,..., 18 z are the blade widths of the moving blades 16 and the stationary blades 20 (the lengths of the blades in a direction substantially perpendicular to the rotor shaft 14) as the steam passage 12 moves from the upstream side to the downstream side. ) Is configured to be long. The stage 18 on the most downstream side of the steam passage 12 is referred to as a “low pressure final stage”. The stationary blade 20 of the low-pressure final stage 18 has a particularly long blade width compared to the stationary blade 20a in the upstream stage 18a. In the low-pressure final stage 18, a plurality of stationary blades 20 are arranged at a predetermined interval in the circumferential direction of the rotor shaft 14 (indicated by an arrow P in the drawing) as shown in FIGS. 2 and 3. Is forming.

  Next, the configuration of the stationary blade 20 according to the present embodiment will be described with reference to FIGS. FIG. 4 is a view showing an airfoil shape of a stationary blade, FIG. 5 is a view of the stationary blade viewed from the ventral side, and FIG. 6 is a perspective view of a plate-like spring member. 4 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 4, the stationary blade 20 includes a ventral member 25 that mainly configures the ventral side, and a dorsal member 27 that mainly configures the dorsal side. The abdominal member 25 and the dorsal member 27 are formed by bending metal plate-like members in different ways of warping. The abdomen side member 25 is warped so that the surface thereof becomes the abdominal surface 24 of the stationary blade 20. On the other hand, the back member 27 is warped so that the surface thereof becomes the back surface 26 of the stationary blade 20.

  As shown in FIG. 5, the abdominal member 25 and the dorsal member 27 extend in the wing span direction (indicated by arrow S) over substantially the same length. In addition, the ventral member 25 has a plurality of front edge side slits 28a and rear edge side slits 28c.

  The “blade width direction” is a direction perpendicular to the cross section of the airfoil shown in FIG. 4, and is a direction orthogonal to the average warp line of the wing (also referred to as a skeleton line, indicated by a one-dot chain line C in the figure). is there. In this embodiment, the “blade width direction” is substantially the same as the radial direction R of the rotor shaft 14.

  The stationary blade 20 is formed by combining the ventral member 25 and the back member 27 and welding and joining them at the front edge portion 36 and the rear edge portion 38 (welded portions are indicated by reference numerals 37 and 39). It is formed. As a result, a cavity 40 extending along the blade width direction S is formed inside the stationary blade 20, that is, between the back surface 25 a of the ventral member 25 and the back surface 27 a of the back member 27. Inside the stationary blade 20, the blade inner surface (25 a, 27 a) is formed by the back surface 25 a of the abdominal member 25 and the back surface 27 a of the back member 27.

  Thus, in the stationary blade 20 of the present embodiment, the ventral member 25 constitutes the ventral portion of the present invention, which is a portion on the ventral side of the cavity 40 of the stationary blade 20, and the back member 27 is the stationary blade. The back side part of this invention used as the back | dorsal part from the 20 cavity 40 is comprised.

  The cavity 40 formed inside the stationary blade 20 communicates with the outside of the stationary blade 20 through slits 28 a and 28 c formed in the ventral member 25. In the stationary blade 20 in which the cavity 40 and the slits 28a and 28c are formed, the water adhering to the abdominal surface 24 moves along the abdominal surface 24 under the vapor pressure, for example, as shown by an arrow W in FIG. Can flow into the cavity 40.

  The water taken into the cavity 40 flows in the blade width direction S toward the shroud 30. As shown in FIG. 3, the shroud 30 is formed with an opening 31 communicating with the cavity 40 of the stationary blade 20, and water in the cavity 40 can be discharged from the opening 31 as indicated by an arrow E. ing.

  As described above, the hollow stationary blade 20 having the cavity 40 inside has a relatively low natural frequency as compared with the solid stationary blade having no cavity inside. Self-excited vibration (flutter) is likely to occur. When the self-excited vibration occurs, the stationary blade 20 is bent or twisted due to elastic deformation, and a relative position variation occurs between the abdominal member 25 and the back member 27 of the stationary blade 20.

  In order to attenuate this relative positional variation, the stationary blade 20 according to the present embodiment is provided with a sliding contact member that can slide from the cavity 40 to the blade inner surface (25a, 27a). When this is elastically deformed, the sliding contact member is caused to generate friction between the blade inner surfaces (25a, 27a), which will be described in detail below.

  In the stationary blade 20 of the present embodiment, as shown in FIG. 4, a corrugated leaf spring 44 having a corrugated cross section is provided between the ventral member 25 and the back member 27 as the sliding contact member. Yes. The corrugated leaf spring 44 has top portions 46 a, 46 c, 46 e (hereinafter referred to as front side top portions) on the front side in contact with the back surface 25 a of the ventral member 25. Further, the corrugated leaf spring 44 is in contact with the back surface 27 a of the back member 27 at the back side top portions 48 a, 48 c, 48 e, 48 g (hereinafter referred to as the back side top portion).

  As shown in FIG. 6, the corrugated leaf spring 44 is a flat plate member made of metal extending in the longitudinal direction (indicated by an arrow L in the drawing) in the width direction (indicated by an arrow W in the drawing). It is curved so that mountain folds and valley folds continue alternately. The corrugated leaf spring 44 is formed so that the envelope connecting the front side top portions 46a, 46c, 46e extends along the back side member 25 along the back surface 25a, and the envelope connecting the back side top portions 48a, 48c, 48e, 48g, The back side member 27 is formed along the back surface 27a. The corrugated leaf spring 44 is positioned so that the longitudinal direction L is the blade width direction S of the stationary blade 20, and is inserted into the cavity 40 between the ventral member 25 and the dorsal member 27.

  Thus, in the state (initial state) arrange | positioned in the cavity 40, the waveform leaf | plate spring 44 is formed so that it may be elastically deformed slightly by bending. Due to this elastic force, as shown in FIG. 4, the corrugated leaf spring 44 has the front side top portions 46a, 46c, 46e pressing the ventral member 25 from the back surface 25a, and the back side top portions 48a, 48c, 48e, 48g are back sides. The member 27 is pressed from the back surface 27a. That is, the corrugated leaf spring 44 is configured to urge (push and spread) the abdominal member 25 and the dorsal member 27 outward in the blade thickness direction of the stationary blade 20 when disposed in the cavity 40. Yes.

  The “blade thickness direction” is a direction parallel to the cross section of the airfoil shown in FIG. 4, and means a direction orthogonal to the average warp line of the blade (shown by a one-dot chain line C in the figure).

  In the stationary blade 20 configured as described above, the front side top portions 46a, 46c, 46e of the corrugated leaf spring 44 and the back surface 25a of the ventral member 25, and the back side top portions 48a, 48c, 48e, 48g of the corrugated leaf springs. A biasing force (pressing force) due to the bending of the corrugated leaf spring 44 is acting between the back surface 27a of the back side member 27 and the stationary blade 20 is elastically deformed so that the back surface 25a of the back side member 25 and the back surface 27a of the back side member 25 are back. When a relative position variation occurs between the side member 27, a dynamic frictional force having a magnitude corresponding to the biasing force can be applied.

  Next, the operation and effect of the stationary blade 20 according to the present embodiment will be described with reference to FIG. During operation of the steam turbine 1, depending on the operating conditions, self-excited vibration may occur in the stationary blade 20, and the stationary blade 20 may be elastically deformed. For example, the back side 25a of the abdominal member 25 and the back side of the back side member 27 are formed by elastically deforming the abdominal member 25 toward the rear edge 38 and the back side member 27 elastically deforming toward the front edge 36. There may be a relative positional fluctuation between the terminal 27a and the terminal 27a.

  At this time, the corrugated leaf spring 44 is at least between the front side top portions 46a, 46c, 46e and the back surface 25a of the abdominal side member 25 and between the back side top portions 48a, 48c, 48e, 48g and the back surface 27a of the back side member 27. Between them, a dynamic friction force is generated in a direction that suppresses relative positional fluctuation between the ventral member 25 and the dorsal member 27. This dynamic friction force attenuates the relative positional fluctuation between the ventral member 25 and the dorsal member 27. As a result, self-excited vibration generated in the stationary blade can be suppressed.

  As described above, in the stationary blade 20 of the present embodiment, the corrugated leaf spring 44 is provided as a sliding member capable of sliding contact from the cavity to the blade inner surface. When the stationary blade 20 is elastically deformed, the corrugated leaf spring 44 comes into sliding contact with the blade inner surface (25a, 27a) from the cavity 40, and causes friction between the blade inner surface (25a, 27a). By attenuating the elastic deformation of the stationary blade 20 by this friction, the self-excited vibration generated in the stationary blade 20 can be suppressed.

  Further, in the stationary blade 20 of the present embodiment, the ventral member 25 and the back are disposed between the ventral member 25 that is a portion on the ventral side of the cavity 40 and the backside member 27 that is a portion on the backside of the cavity 40. A corrugated leaf spring 44 is provided as a sliding contact member that is in sliding contact with at least one of the side members 27. When the stationary blade 20 is elastically deformed, the corrugated leaf spring 44 causes friction between at least one of the ventral member 25 and the dorsal member 27. This friction attenuates the relative positional fluctuation between the ventral member 25 and the dorsal member 27.

  Further, in the stationary blade 20 of this embodiment, a corrugated leaf spring 44 is provided as a biasing member that biases the abdominal member 25 and the back member 27 outward in the blade thickness direction. When a relative position change occurs between the ventral member 25 and the dorsal member 27, the corrugated leaf spring 44 applies a dynamic frictional force having a magnitude corresponding to the biasing force between the ventral member 25 and the dorsal member 27. It can be generated between at least one of them. By selecting the rigidity of the corrugated leaf spring 44 as the urging member and adjusting the urging force in the state of being disposed in the cavity (initial state), the position variation between the abdominal member 25 and the back member 27 can be reduced. The attenuation characteristic can be set to a desired characteristic.

  Further, the stationary blade 20 of the present embodiment has a plate shape extending along the blade width direction, and the corrugated leaf spring 44 is a plate-like spring member that presses the abdominal member 25 and the back member 27 by the elastic force caused by the bending. Is provided. An urging member extending in the longitudinal direction of the plate-like member, that is, the blade width direction of the stationary blade can be easily realized simply by bending the rectangular plate-like member in the width direction by press molding or the like.

  Further, in the stationary blade 20 of this embodiment, the corrugated leaf spring 44 has a corrugated cross section, and the ventral member 25 and the dorsal member 27 have corrugated tops 46a, 46c, 46e, 48a, 48c. , 48e, 48g are in contact. By making the plate-like spring member into such a wave shape, it is possible to make sliding contact with both the ventral member 25 and the dorsal member 27 at a plurality of tops. Thereby, the corrugated leaf | plate spring 44 can produce a favorable friction between the ventral | abdominal member 25 and / or the back | dorsal member 27. FIG.

  The stationary blade according to the present embodiment will be described with reference to FIG. FIG. 7 is a view showing an airfoil of a stationary blade. Unlike the stator blade according to the first embodiment, the stator blade according to this embodiment will be described in detail below in terms of being manufactured by combining a plate spring member and a back member. In addition, about the structure substantially common with the stationary blade which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The stationary blade 20B is manufactured as follows. First, the corrugated leaf spring 44 is fixed to the back member 27. Specifically, back-side top portions 48a, 48c, 48e, and 48g of the corrugated leaf spring 44 are joined to the back surface 27a of the back-side member 27 by spot welding (welded portions are indicated by reference numerals 50a, 50c, 50e, and 50g).

  In this embodiment, spot welding is used to fix the back member 27 and the corrugated leaf spring 44, but the coupling method is not limited to this. It is also preferable to form a hole in the dorsal member 27 and to perform bonding using so-called “plug welding” in which welding is performed so as to fill the hole.

  Then, the back side member 27 to which the corrugated leaf spring 44 is coupled and the abdominal side member 25 are combined, and coupled by welding at the front edge portion 36 and the rear edge portion 38 of the stationary blade 20B. Specifically, the front edge 27f of the back member 27 and the front edge 25f of the abdominal member 25 are joined together by welding, and the rear edge 27t of the back member 27 and the rear edge 25t of the abdominal member 25 are joined together. Are joined by welding.

  In the stationary blade 20 </ b> B configured in this manner, the front side top portions 46 a, 46 c, 46 e of the wave plate spring 44 are in sliding contact with the back surface 25 a of the ventral member 25. When the stationary blade 20B is elastically deformed, the corrugated leaf spring 44 causes friction between the front side top portions 46a, 46c, 46e and the back surface 25a of the ventral member 25. This friction attenuates the relative positional fluctuation between the ventral member 25 and the dorsal member 27. As a result, self-excited vibration generated in the stationary blade can be suppressed.

  As described above, in the stationary blade 20B according to the present embodiment, the abdominal side member 25 and the back side member 27 are coupled to each other at the front edge portion 36 and the rear edge portion 38 of the stationary blade 20B. The corrugated leaf spring 44 as a member is coupled to the back member 27. Thereby, the stator blade 20 can be easily manufactured only by joining the stator blade provided with the plate-like spring member between the abdominal member 25 and the back member 27 by welding. In addition, since the corrugated leaf spring 44 can be fixed at a desired position between the ventral member 25 and the dorsal member 27, the position fluctuation attenuation characteristic between the ventral member 25 and the dorsal member 27 can be reduced. It is possible to suppress the occurrence of variations in the thickness.

  In the stationary blade 20B according to the present embodiment, the corrugated leaf spring 44 is coupled to the back member 27, but the counterpart to which the corrugated leaf spring 44 is coupled is not limited thereto. . The corrugated leaf spring 44 may be coupled to the ventral member 25.

  A stationary blade according to the present embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 is a view showing an airfoil shape of a stationary blade, and FIG. 9 is a perspective view of a plate spring member. Unlike the stator blade according to the first embodiment, the stator blade according to the present embodiment is described below in detail in that a “C-shaped leaf spring” having a substantially C-shaped cross section is provided as a plate spring member. Will be explained. In addition, about the structure substantially common with the stationary blade which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

   As shown in FIG. 8, in the stationary blade 20 </ b> C according to the present embodiment, a C-shaped leaf spring 52 having a substantially C-shaped cross section is provided between the abdominal member 25 and the back member 27 as the leaf spring member. Is provided. In the C-shaped leaf spring 52, the outer surfaces 54 a and 55 a of the open end portions 54 and 55 are in contact with the back surface 25 a of the ventral member 25. In addition, the outer surface 56 a of the base portion 56 is in contact with the back surface 27 a of the back member 27 in the C-shaped leaf spring 52. In other words, when the C-shaped leaf spring 52 is disposed in the cavity 40, the open end portions 54 and 55 are in contact with the ventral member 25 and the base portion 56 is in contact with the back member 27.

  As shown in FIG. 9, the C-shaped leaf spring 52 is formed by bending a metal plate-like member extending in the longitudinal direction L so as to be rounded in the width direction W. The C-shaped leaf spring 52 is formed so that the open end portions 54, 55 are along the back surface 25 a of the abdominal member 25, and the base portion 56 is formed along the back surface 27 a of the back side member 27. The C-shaped leaf spring 52 is positioned so that the longitudinal direction L thereof is the blade width direction of the stationary blade, and the base portion 56 is fixed to the back member 27 by welding as shown in FIG. (Indicated by reference numeral 58). In this way, the C-shaped leaf spring 52 is disposed in the cavity 40.

  Thus, in the state (initial state) arrange | positioned in the cavity 40, the C-shaped leaf | plate spring 52 is formed so that it may be elastically deformed slightly by bending. Due to this elastic force, the outer surfaces 54a and 55a of the open ends 54 and 55 press the ventral member 25 from the back surface 25a, and the outer surface 56a of the base 56 presses the back member 27 from the back surface 27a. It is supposed to be. That is, the C-shaped leaf spring 52 urges the abdominal member 25 and the back member 27 outward in the blade thickness direction of the stationary blade 20C (direction perpendicular to the dashed line C in FIG. 8). It is configured.

  In the stator blade 20C configured in this way, the outer surfaces 54a and 55a of the open ends 54 and 55 of the C-shaped leaf spring 52 are in contact with the back surface 25a of the ventral member 25, and between the outer surfaces 54a and 55a and the back surface 25a. The urging force by the bending of the C-shaped leaf spring 52 is acting.

  When the stationary blade 20 </ b> C is elastically deformed, the C-shaped plate spring 52 generates a dynamic friction force corresponding to the urging force between the outer surfaces 54 a and 55 a of the open end portions 54 and 55 and the rear surface 25 a of the ventral member 25. This dynamic friction force attenuates the relative positional fluctuation between the ventral member 25 and the dorsal member 27. As a result, self-excited vibration generated in the stationary blade can be suppressed.

  As described above, in the stationary blade 20C according to the present embodiment, the plate-like spring member has a C-shaped cross section, the C-shaped open end portions 54 and 55 are in contact with the ventral member 25, and the dorsal member 27 Is provided with a C-shaped leaf spring 52 with which a C-shaped base 56 contacts. By making the plate-like spring member into such a C shape, it is possible to make sliding contact with the ventral member 25 with a sufficient area, and when the stationary blade is elastically deformed, friction is generated between it and the ventral member. Can be made.

  In the stationary blade 20C according to the present embodiment, the C-shaped leaf spring 52 is configured such that the base 56 is fixed to the back member 27. However, the fixing partner of the C-shaped leaf spring 52 is not limited thereto. It is not something. The C-shaped leaf spring 52 may have the open end portions 54 and 55 fixed to the ventral member 25. In this case, the base portion 56 of the C-shaped leaf spring 52 can be slidably contacted with the back side member 27 with a sufficient area, and when the stationary blade is elastically deformed, the friction with the back side member 27 is favorably generated. be able to.

  The stationary blade according to the present embodiment will be described with reference to FIGS. 10 and 11. FIG. 10 is a view showing the airfoil shape of a stationary blade, and FIG. 11 is a perspective view of a plate spring member. The stator blade according to the present embodiment is different from the stator blade according to the first embodiment in that a “bow-shaped leaf spring” having a cross-section having a bow shape is provided as a plate-like spring member. . In addition, about the structure substantially common with the stationary blade which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

   As shown in FIG. 10, in the stationary blade 20 </ b> D according to the present embodiment, an arcuate leaf spring 60 having a cross-sectional arc shape is provided between the ventral member 25 and the dorsal member 27 as a plate-like spring member. Yes. The arcuate leaf spring 60 has its front surfaces 62 a and 63 a in contact with the back surface 25 a of the ventral member 25. In addition, the back surface 64 a of the base portion 64 of the arcuate leaf spring 60 is in contact with the back surface 27 a of the back member 27. That is, when the arcuate leaf spring 60 is disposed in the cavity 40, the end portions 62 and 63 of the arcuate leaf spring 60 are in contact with the ventral member 25 and the base portion 64 is in contact with the back member 27.

  As shown in FIG. 11, an arcuate leaf spring 60 is formed by bending a metal plate-like member extending in the longitudinal direction L by forming two gentle mountain folds and valley folds in the width direction W. is there. The bow leaf spring 60 is formed so that the end portions 62 and 63 are along the back surface 25 a of the ventral member 25, and the base portion 64 is formed along the back surface 27 a of the back member 27. The arcuate leaf spring 60 is positioned such that its longitudinal direction L is in the blade width direction of the stationary blade 20D, and the base 64 is fixed to the back member 27 by welding (the welded portion is indicated by reference numeral 66). In this way, the bow leaf spring 60 is disposed in the cavity 40.

  Thus, in the state (initial state) arrange | positioned in the cavity 40, the arched leaf | plate spring 60 is formed so that it may be elastically deformed slightly by bending. Due to this elastic force, the arcuate leaf spring 60 has the surfaces 62a and 63a of the end portions 62 and 63 pressing the ventral member 25 from the back surface 25a and the back surface 64a of the base portion 64 pressing the back member 27 from the back surface 27a. It is like that. That is, the arcuate leaf spring 60 is configured to urge the abdominal member 25 and the dorsal member 27 outward in the blade thickness direction of the stationary blade 20D (direction perpendicular to the dashed line C in FIG. 10). Has been.

  In the stator blade 20D configured as described above, the surfaces 62a and 63a of the end portions 62 and 63 of the arcuate leaf spring 60 are in sliding contact with the back surface 25a of the ventral member 25, and between the front surfaces 62a and 63a and the back surface 25a. The urging force due to the bending of the bow leaf spring 60 is applied.

  When the stationary blade 20D is elastically deformed, the arcuate leaf spring 60 generates a dynamic friction force according to the biasing force between the surfaces 62a and 63a of the end portions 62 and 63 and the back surface 25a of the ventral member 25. This dynamic friction force attenuates the relative positional fluctuation between the ventral member 25 and the dorsal member 27. As a result, self-excited vibration generated in the stationary blade can be suppressed.

  In this embodiment, as shown in FIG. 11, the bow leaf spring 60 acts on the ventral member 25 and the dorsal member 27 by changing the bending angle θ formed by the base 64 and the connecting portion 68. It is possible to easily adjust the force, that is, the dynamic friction force generated when the stationary blade 20D is elastically deformed.

  As described above, in the stationary blade 20D according to the present embodiment, as a plate-like spring member, the cross section has an arcuate shape, the ventral member 25 is in contact with the arcuate ends 62 and 63, and the dorsal member 27 has an arcuate shape. An arcuate leaf spring 60 is provided in contact with the base 64. By making the plate-shaped spring member into such an arcuate shape, it can be slidably contacted with the ventral member with a sufficient area, and when the stationary blade is elastically deformed, the friction with the ventral member is satisfactorily generated. Can do. A plate-like spring member can be realized only by forming two gentle mountain folds and two valley folds on a flat plate-like member.

  In addition, in the stationary blade 20D according to the present embodiment, the base part 64 of the arcuate leaf spring 60 is fixed to the back member 27, but the fixing counterpart of the arcuate leaf spring 60 is limited to this. It is not a thing. The arcuate leaf spring 60 may have its ends 62 and 63 fixed to the ventral member 25. In this case, the base of the arched leaf spring can be slidably contacted with the back member with a sufficient area, and when the stationary blade is elastically deformed, friction can be generated between the back blade and the back member.

  The stationary blade according to the present embodiment will be described with reference to FIGS. 12 and 13. FIG. 12 is a view showing an airfoil shape of a stationary blade, and FIG. 13 is a perspective view of a plate spring member. Unlike the stationary blade according to the first embodiment, the stationary blade according to the present embodiment is different from the stationary blade according to the first embodiment in that a plurality of “U-shaped leaf springs” having a U-shaped cross section are provided as plate-shaped spring members. Details will be described in the following. In addition, about the structure substantially common with the stationary blade which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 12, in the stationary blade 20E according to the present embodiment, U-shaped plate springs 70, 72, and 74 having a substantially U-shaped cross section are provided as the plate-shaped spring members. It is provided between the side members 27. The U-shaped leaf spring 70 is disposed closer to the front edge portion 36 than the front edge side slit 28a, and the U-shaped leaf spring 72 is disposed between the front edge side slit 28a and the rear edge side slit 28c. The U-shaped plate spring 74 is disposed closer to the rear edge 38 than the rear edge slit 28c.

  In these U-shaped plate springs 70, 72, 74, the outer surfaces 76 a, 82 a, 88 a of the first arm portions 76, 82, 88 are in contact with the back surface 25 a of the ventral member 25. In addition, the U-shaped plate springs 70, 72, and 74 have the outer surfaces 78 a, 84 a, and 90 a of the second arm portions 78, 84, and 90 in contact with the back surface 27 a of the back member 27.

  As shown in FIG. 13, the U-shaped leaf spring 70 is formed by bending a metal plate-like member extending in the longitudinal direction L by bending it at about 90 degrees in two places in the same direction in the width direction W. is there. The U-shaped leaf spring 70 is formed so that the first arm portion 76 is along the back surface 25 a of the abdominal member 25, and the second arm portion 78 is formed along the back surface 27 a of the back side member 27. Has been. The U-shaped plate springs 72 and 74 have substantially the same configuration as the U-shaped plate spring 70. The U-shaped plate springs 70, 72, 74 are positioned so that the longitudinal direction L thereof is the blade width direction of the stationary blade 20 </ b> E, and the second arm portions 78, 84, 90 are welded to the back member 27. (Welded portions are denoted by reference numerals 94, 96, and 98, respectively). In this way, the U-shaped plate springs 70, 72 and 74 are disposed in the cavity 40.

  Thus, in the state (initial state) arrange | positioned in the cavity 40, the U-shaped leaf | plate springs 70, 72, and 74 are formed so that it may be elastically deformed slightly by bending. Due to this elastic force, the U-shaped plate springs 70, 72, 74 cause the outer surfaces 76 a, 82 a, 88 a of the first arm portions 76, 82, 88 to press the ventral member 25 from the back surface 25 a and the second arm portion. The outer surfaces 78a, 84a, 90a of 78, 84, 90 press the back side member 27 from the back surface 27a. In other words, the U-shaped leaf springs 70, 72, and 74 have the ventral member 25 and the dorsal member 27 outward from the blade thickness direction of the stationary blade 20E (the direction perpendicular to the dashed line C in FIG. 12). It is configured to be energized.

  In the stationary blade 20E configured as described above, the outer surfaces 76a, 82a, 88a of the first arm portions 76, 82, 88 of the U-shaped plate springs 70, 72, 74 are in sliding contact with the back surface 25a of the ventral member 25. The urging force due to the bending of the U-shaped plate springs 70, 72, and 74 acts between the outer surfaces 76a, 82a, and 88a and the back surface 25a. When the stationary blade 20E is elastically deformed, the U-shaped plate springs 70, 72, 74 are attached between the outer surfaces 76a, 82a, 88a of the first arm portions 76, 82, 88 and the rear surface 25a of the abdominal member 25. A dynamic friction force corresponding to the force is generated. This dynamic friction force attenuates the relative positional fluctuation between the ventral member 25 and the dorsal member 27. As a result, self-excited vibration generated in the stationary blade can be suppressed.

  As described above, in the stationary blade 20E according to the present embodiment, the plate-like spring member has a substantially U-shaped cross section, and the ventral member 25 has a U-shaped first arm portion 76, 82, 88. Are in contact with each other, and the back member 27 is provided with U-shaped plate springs 70, 72, and 74 that are in contact with the second arm portions 78, 84, and 90. By making the plate-shaped spring member into such a U-shape, the plate-shaped spring member can be easily manufactured. Further, since the plate-like spring member is compact, it can be easily disposed in the cavity.

  A stationary blade according to the present embodiment will be described with reference to FIG. FIG. 14 is a view showing the airfoil of the stationary blade. Unlike the stationary blade according to the fifth embodiment, the stationary blade according to the present embodiment will be described in detail below in that a cavity that does not communicate with the outside through the slit is filled with a damping material. In addition, about the structure substantially common with the stationary blade which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 14, in the stationary blade 20 </ b> F according to the present embodiment, a U-shaped plate spring 70 is provided between the ventral member 25 and the back member 27 as a plate spring member. The U-shaped leaf spring 70 is disposed closer to the front edge portion 36 than the front edge side slit 28a. In the U-shaped plate spring 70, the outer surface 76a of the first arm portion 76 is in contact with the back surface 25a of the abdominal member 25, and the second arm portion 78 is fixed to the back member 27 by welding.

  By arranging the U-shaped leaf spring 70 in this way, the space between the abdominal member 25 and the back member 27 is closer to the front edge 36 than the base 80 of the U-shaped leaf spring 70. The cavity 40a and the cavity 40c on the rear edge 38 side of the base 80 of the U-shaped leaf spring 70 are partitioned.

  The cavity 40c on the trailing edge 38 side communicates with the outside of the stationary blade 20F through slits 28a and 28c. The water adhering to the ventral surface 24 of the stationary blade 20F flows into the cavity 40c from the slits 28a and 28c. The water taken into the cavity 40c flows toward the shroud (see FIG. 3) in the wing width direction.

  On the other hand, the cavity 40a on the front edge 36 side does not communicate with the outside of the stationary blade 20F through the slits (28a, 28c). That is, the cavity 40a does not have a function of taking water from the abdominal surface and flowing it toward the shroud.

  Therefore, in the stationary blade 20F according to the present embodiment, the damping material 110 is provided in the cavity 40a. Examples of the damping material include rubber-based and plastic-based materials.

  In the stator blade 20F configured in this manner, the outer surface 76a of the first arm portion 76 of the U-shaped leaf spring 70 is in contact with the back surface 25a of the ventral member 25, and between the outer surface 76a and the back surface 25a, The biasing force of the U-shaped leaf spring 70 is acting.

  When the stationary blade 20F is elastically deformed, the U-shaped leaf spring 70 generates a dynamic friction force according to the urging force between the outer surface 76a of the first arm portion 76 and the rear surface 25a of the abdominal member 25, and the cavity The damping material 110 provided in 40a is deformed, and the deformation resistance of the damping material 110 acts on the ventral member 25 and the back member 27. Thereby, the relative position fluctuation between the ventral member 25 and the dorsal member 27 is attenuated. As a result, self-excited vibration generated in the stationary blade can be suppressed.

  As described above, in the stationary blade 20F according to the present embodiment, among the cavities (40a, 40c) partitioned by the U-shaped leaf springs 70, they do not communicate with the outside via the slits (28a, 28c). A damping material 110 is provided in the cavity 40a. The relative position fluctuation between the ventral member 25 and the dorsal member 27 can be attenuated using the deformation resistance of the damping material 110.

  A steam turbine according to the present embodiment will be described with reference to FIG. FIG. 15 is a perspective view showing the arrangement of the stationary blades in the low-pressure final stage of the steam turbine. In the steam turbine according to the present embodiment, the stationary blade of the above embodiment (hereinafter referred to as a hollow stationary blade) and a solid stationary blade having no cavity inside are arranged in the same stage. Unlike the steam turbine 1 according to the first embodiment, the details will be described below. In addition, about the structure substantially common with the stationary blade which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 15, the steam turbine 1B according to the present embodiment includes a hollow stationary blade 20 according to the first embodiment and a solid stationary blade 120 having no cavity inside in the blade group 19B of the low-pressure final stage 18B. The rotor shaft is circumferentially arranged in the circumferential direction P. The solid stationary blade 120 has an outer shape (geometric shape) substantially the same as that of the hollow stationary blade 20. Each of the hollow stationary blade 20 and the solid stationary blade 120 has one end fixed to the blade root ring 32 and the other end fixed to the inner shroud 30.

  In the inner shroud 30, an opening 31 communicating with the cavity 40 is formed at a position corresponding to the cavity 40 of the hollow stationary blade 20. Moisture taken into the cavity 40 from the slit (see FIG. 4) by the hollow stationary blade 20 is discharged from the opening 31.

  As described above, in the steam turbine 1B according to the present embodiment, the hollow stationary blade 20 having the cavity 40 inside and the solid stationary blade 120 having no cavity inside are mixedly arranged in the blade group 19B of the same stage 18B. Has been. For this reason, it is possible to arrange the hollow stationary blade and the solid stationary blade having different natural frequencies adjacent to each other without changing the exterior shape of the stationary blade. As a result, self-excited vibrations caused by the fact that the blades of the same stage have substantially the same natural frequency are arranged adjacent to each other can be suppressed.

  Further, in the steam turbine 1B according to the present embodiment, the hollow stationary blades 20 in the blade group 19B of the same stage 18B are arranged at a predetermined interval in the rotor shaft circumferential direction P. As a result, the solid stator blade 120 having the same exterior shape and different natural frequency is disposed with high probability next to the hollow stator blade 20. A solid stator blade that is less prone to self-excited vibration (flutter) can be placed next to a hollow stator blade that is easy to generate self-excited vibration (flutter) because of its light weight, and the above-described self-excited vibration can be suppressed. .

  Further, in the steam turbine 1B according to the present embodiment, the hollow stationary blades 20 and the solid stationary blades 120 are alternately arranged in the blade group 19B of the same stage 18B. Adjacent stationary blades in the same stage blade group can reliably have different natural frequencies.

  In the steam turbine 1B according to the present embodiment, the hollow stationary blades 20 and the solid stationary blades 120 are alternately arranged. However, the arrangement of the hollow stationary blades is not limited thereto. It is only necessary that the hollow stationary blades and the solid stationary blades having different natural frequencies be arranged as close as possible. For example, one solid stationary blade may be arranged every two hollow stationary blades. As a result, one solid stationary blade can always be arranged next to the hollow stationary blade. The self-excited vibration generated in the stationary blades can be suppressed as much as possible while arranging as many hollow stationary blades as possible to take in and remove moisture adhering to the blade surface into the cavity.

  A steam turbine according to the present embodiment will be described with reference to FIG. FIG. 16 is a perspective view showing the arrangement of the stationary blades in the low-pressure final stage of the steam turbine. In the steam turbine according to the present embodiment, among the hollow stator blades of Embodiments 1 to 6, the first stator blade and the second stator blade having different natural frequencies are mixedly arranged in the same stage. In this regard, unlike the steam turbine 1 according to the first embodiment, details will be described below. In addition, about the structure substantially common with the stationary blade which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 16, the steam turbine 1C according to the present embodiment includes a hollow stationary blade 20 of the first embodiment (hereinafter referred to as a first stationary blade) in the blade group 19C of the low-pressure final stage 18C. The hollow stator blades 20C of Example 3 (hereinafter referred to as second stator blades) are alternately arranged in the circumferential direction P of the rotor shaft 14. Since the first stationary blade 20 and the second stationary blade 20C have different shapes of the plate spring members provided in the cavity 40 as described above, their natural frequencies are also different. In the first stator blade 20 and the second stator blade 20C, the abdominal member 25 and the back member 27 are the same and have substantially the same exterior shape (geometric shape).

  Each of the first stator blade 20 and the second stator blade 20 </ b> C has one end fixed to the blade root ring 32 and the other end fixed to the inner shroud 30. In the inner shroud 30, an opening 31 communicating with the cavity 40 is formed at a position corresponding to the cavity 40 of the first stationary blade 20 and the second stationary blade 20 </ b> C. The moisture taken into the cavity 40 from the slit (see FIG. 4) by the first stationary blade 20 and the second stationary blade 20C is discharged from the opening 31.

  As described above, in the steam turbine 1C according to the present embodiment, the first stator blade 20 and the second stator blade 20C having different natural frequencies are mixedly arranged in the blade group 19C of the same stage 18C. For this reason, it becomes possible to arrange | position the hollow stationary blades from which a natural frequency differs adjacently, without making the exterior shape of a stationary blade different. As a result, self-excited vibration caused by the fact that stationary blades having substantially the same natural frequency are arranged next to each other in the same stage while using only hollow stationary blades that can take in and remove moisture adhering to the blade surface. Can be suppressed.

  In the steam turbine 1 </ b> C according to the present embodiment, the first stationary blades 20 are arranged in the rotor shaft circumferential direction P at a predetermined interval. For this reason, the second stationary blade 20 </ b> C having a different natural frequency is surely arranged next to the first stationary blade 20. Even when only hollow vanes are used in the same stage blade group, it is possible to more reliably suppress the occurrence of self-excited vibration caused by the fact that substantially equal natural frequencies are arranged adjacent to each other. .

  Moreover, in the steam turbine 1C according to the present embodiment, the first hollow stationary blades 20 and the second hollow stationary blades 20C are alternately arranged. Adjacent hollow stationary blades in the same stage blade group can reliably have different natural frequencies.

  In the steam turbine 1C according to the present embodiment, the first stationary blades 20 and the second stationary blades 20C are alternately arranged, but the arrangement of the hollow stationary blades is not limited to this. Of the hollow stationary blades described in Examples 1 to 6, it is preferable to select two types having different natural frequencies as much as possible and to alternately arrange them in the same stage blade group.

  The stationary blade according to the present embodiment will be described with reference to FIG. FIG. 17 is a view showing the airfoil of the stationary blade. The stationary blade 20G according to the present embodiment is provided substantially orthogonal to the average warp line (center line connecting the leading edge and the trailing edge) C of the blade, and the cavity (inside the stationary blade 20G) 40 is placed in front. A plate-shaped rib (partition wall: partition wall) 130 is provided that divides into a cavity (cavity) C1 on the edge side and a cavity (cavity) C2 on the rear edge side, and the damping material 131 is provided in the cavity C2 on the rear edge side. Unlike the stationary blade according to the above embodiment in that it is filled, the details will be described below. In addition, about the structure substantially common with the stationary blade which concerns on the said Example, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As the damping material 131 according to the present embodiment, for example, a steel ball as shown in FIG. Further, the damping material 110 made of the rubber or plastic material described in the sixth embodiment can be filled in the cavity C2 on the trailing edge side.

  According to the stationary blade 20G according to the present embodiment, when the stationary blade 20G is elastically deformed, the steel balls 131 filled in the cavity C2 collide with each other (rubbing) and friction damping occurs (or Then, the damping material 131 made of a rubber or plastic material provided in the cavity C2 is deformed, and the deformation resistance of the damping material 131 acts on the abdominal member 25 and the dorsal member 27. ). Thereby, the relative position fluctuation between the ventral member 25 and the dorsal member 27 is attenuated. As a result, self-excited vibration generated in the stationary blade can be suppressed.

As described above, in the stationary blade 20G according to the present embodiment, the damping material 131 is provided in the cavity C2 partitioned by the rib 130. The relative position fluctuation between the ventral member 25 and the dorsal member 27 can be attenuated using the deformation resistance of the damping material 131.
Further, in the stationary blade 20G according to the present embodiment, since the damping material 131 is filled in the cavity C2 on the trailing edge side instead of the leaf spring, the dimensional tolerance of the leaf spring and the blade (abdominal side) It is possible to prevent the contact of the leaf spring caused by the dimensional tolerance of the member 25 and the back member 27).
Other functions and effects are the same as those of the above-described embodiment, and thus the description thereof is omitted here.

  A stationary blade according to the present embodiment will be described with reference to FIG. FIG. 18 is a diagram illustrating the airfoil of the stationary blade. The stationary blade 20 </ b> H according to the present embodiment is arranged such that the end portions 62 and 63 of the arcuate leaf spring 60 are along the back surface 27 a of the back member 27, and the base portion 64 is along the back surface 25 a of the ventral member 25. Unlike the stationary blade 20D according to the fourth embodiment, the details will be described below. In addition, about the structure substantially common with the stationary blade 20D which concerns on Example 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

According to the stationary blade 20H according to the present embodiment, when the arcuate leaf spring 60 is assembled into the cavity 40, the end portions 62 and 63 of the arcuate leaf spring 60 are larger than the curvature of the back surface 25a of the ventral member 25. Since it is formed so as to be surely pressed against the back surface 27a of the back-side member 27 having a curvature, the end portions 62 and 63 of the bow-shaped leaf spring 60 are reliably brought into contact (contact) with the back surface 27a of the back-side member 27. ), And can prevent the leaf springs from coming into contact with each other due to the dimensional tolerances of the leaf springs and the dimensional tolerances of the wings (the ventral member 25 and the dorsal member 27).
Other functions and effects are the same as those of the above-described fourth embodiment, and thus description thereof is omitted here.
Note that the two-dot chain line in FIG. 18 indicates the cross-sectional shape of the arcuate leaf spring 60 before being incorporated into the cavity 40.

  The stationary blade according to the present embodiment will be described with reference to FIG. FIG. 19A is a diagram showing the airfoil shape of the stationary blade. Unlike the stationary blade 20 according to the first embodiment, the stationary blade 20J according to the present embodiment is different from the stationary blade 20 according to the first embodiment in that two “bow-shaped leaf springs” having a bow shape in cross section are provided as plate spring members. Details will be described in the following. In addition, about the structure substantially common with the stationary blade which concerns on Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

   As shown in FIG. 19, in the stationary blade 20J according to the present embodiment, the back surfaces 142a and 143a of the base portions 142 and 143 of the arcuate leaf springs 140 and 141 having a bow shape in cross section are slid as plate spring members. The front surfaces 144a and 145a of the end portions 144 and 145 are in contact with the back surface 27a of the back side member 27, and the front surfaces 146a and 147a of the end portions 146 and 147 are in contact with the abdominal side member 25. It is in contact with the back surface 25a. Moreover, each edge part 144,145,146,147 is being fixed by welding (a welding part is shown with the code | symbol 148).

According to the stationary blade 20J according to the present embodiment, the end portions 144 and 145 of the arcuate leaf spring 140 are fixed to the back member 27 by welding, and the end portions 146 and 147 of the arcuate leaf spring 141 are abdominal side by welding. Since it is fixed to the member 25, the contact between the end portions 144, 145 and the dorsal member 27 generated from the dimensional tolerance of the leaf spring and the dimensional tolerance of the wing (the ventral member 25 and the dorsal member 27), In addition, it is possible to reliably prevent the end portions 146 and 147 and the ventral member 25 from coming into contact with each other.
Further, the contact between the back surface 142a of the base portion 142 and the back surface 143a of the base portion 143 is appropriately selected by selecting the material of the arched leaf springs 140 and 141 (selecting a material that does not allow the back surfaces 142a and 143a to contact each other). It can be avoided.
Other functions and effects are the same as those of the above-described first embodiment, and thus description thereof is omitted here.
FIG. 19B shows the cross-sectional shape of the bow leaf springs 140 and 141 before being incorporated into the cavity 40.

  The stationary blade according to the present embodiment will be described with reference to FIG. FIG. 20 is a view showing the airfoil of the stationary blade. The stationary blade 20K according to the present embodiment is different from the stationary blade 20H according to the tenth embodiment in that an arcuate leaf spring 150 is provided instead of the arcuate leaf spring 60, and the details will be described below. In addition, about the structure substantially common with the stationary blade which concerns on Example 10, the same code | symbol is attached | subjected and description is abbreviate | omitted.

   As shown in FIG. 20, the bow leaf spring 150 according to the present embodiment is provided with a first bent portion 154 and a second bent portion 155 between a base portion 151 and end portions 152 and 153, respectively. ing. The base 151 is formed such that the surface 151 a has substantially the same curvature as the curvature of the back surface 25 a of the ventral member 25, and the back surfaces 152 a and 153 a of the end portions 152 and 153 are the back side member 27. Is formed so as to have substantially the same curvature as that of the back surface 27a.

According to the stationary blade 20K according to the present embodiment, when the arcuate leaf spring 151 is incorporated into the cavity 40, the back surfaces 152a and 153a of the end portions 152 and 153 of the arcuate leaf spring 150 are the back surface 27a of the back member 27. Therefore, it is possible to further prevent the contact of the leaf spring caused by the dimensional tolerance of the leaf spring and the dimensional tolerance of the wing (the abdominal member 25 and the dorsal member 27). In addition, the surface pressure (pressing force per unit area) can be reduced, and wear of the end portions 152 and 153 of the arcuate leaf spring 150 and the back member 27 can be reduced.
Other functions and effects are the same as those of the above-described tenth embodiment, and thus description thereof is omitted here.

  In the above-described embodiment, the ventral member 25 constitutes the ventral portion of the stationary blade 20 and the dorsal member 27 constitutes the dorsal portion of the stationary blade 20. The configuration of the part is not limited to this. Any vane may be used as long as it has a cavity formed between the ventral portion and the dorsal portion.For example, the tubular member is crushed into a flat shape and further bent so that the ventral surface of the wing and The present invention can also be applied to a stationary blade that forms a back surface warp and has a hollow formed inside a tubular member.

  In the above-described embodiment, a plate-like spring member (C-shaped plate spring 52; arcuate plate springs 60, 140, 141, 150; U-shaped plate springs 70, 72, 74) is provided as the sliding contact member. However, the sliding member is not limited to this. Any material can be used as long as it can be slidably contacted from the cavity to the inner surface of the blade or the back surfaces of the bases can be slidably contacted. For example, a plastic member or a rubber member can be used.

  Further, in the above-described embodiment, a plate-like spring member (C-shaped plate spring 52; arcuate plate springs 60, 140, 141, 150; U-shaped plate springs 70, 72, 74) is provided as an urging member. However, the urging member is not limited to this. What is necessary is just to be able to urge each of the abdominal side and the back side outward in the blade thickness direction. For example, a coil spring can also be used.

Furthermore, in the embodiment described above, the ends of the plate spring members (C-shaped plate spring 52; arcuate plate springs 60, 150; U-shaped plate springs 70, 72, 74) are formed as shown in FIG. It is more preferable that the structure has a divided structure (or slit structure) divided into a plurality of plates in the thickness direction.
When such a plate-like spring member is employed, when the stationary blade is elastically deformed, friction damping occurs between the divided plates. Thereby, the relative position fluctuation between the abdominal member 25 and the back member 27 can be further attenuated, and the self-excited vibration generated in the stationary blade can be further suppressed.
FIG. 21 shows a specific example when the end portions 152 and 153 of the arched leaf spring 150 are divided.

Furthermore, the relationship between the plate thickness and the attenuation is as shown in FIG. 22, that is, the plate thickness increases (for example, the plate thickness is changed from 1.2 mm to 1.5 mm, or from 1.5 mm to 2 mm). Increase), the attenuation also increases. Here, “damping” is the sum of structural damping, material damping, and friction damping.
Therefore, in the above-described embodiment, the thickness of the plate spring member (C-shaped plate spring 52; arcuate plate springs 60, 150; U-shaped plate springs 70, 72, 74) is changed (controlled) to be desired. Can be obtained.

  As described above, the stationary blade according to the present invention is useful for a steam turbine, and is particularly suitable for a low-pressure steam turbine that receives supply of steam from a moisture separation heater.

1 is a diagram schematically illustrating a schematic configuration of a steam turbine according to Embodiment 1. FIG. It is the external view which looked at the steam turbine concerning Example 1 from the low-pressure last stage side. It is the enlarged view which looked at the stationary blade shown by FIG. 2 from the back side. It is a figure which shows the airfoil of the stationary blade which concerns on Example 1, and is sectional drawing by the AA line of FIG. It is the figure which looked at the stationary blade concerning Example 1 from the ventral side. FIG. 3 is a perspective view of a plate spring member (wave plate spring) according to the first embodiment. FIG. 6 is a diagram illustrating an airfoil of a stationary blade according to a second embodiment. FIG. 6 is a diagram illustrating an airfoil of a stationary blade according to a third embodiment. It is a perspective view of the plate-shaped spring member (C-shaped plate spring) which concerns on Example 3. FIG. FIG. 6 is a diagram illustrating an airfoil of a stationary blade according to a fourth embodiment. It is a perspective view of the plate-shaped spring member (bow-shaped plate spring) which concerns on Example 4. FIG. FIG. 10 is a diagram illustrating an airfoil of a stationary blade according to a fifth embodiment. FIG. 10 is a perspective view of a plate spring member (a U-shaped plate spring) according to a fifth embodiment. FIG. 10 is a diagram illustrating an airfoil of a stationary blade according to a sixth embodiment. FIG. 10 is a perspective view showing an arrangement of stationary blades in a blade group of a low-pressure final stage of a steam turbine according to a seventh embodiment. FIG. 10 is a perspective view showing an arrangement of stationary blades in a blade group of a low-pressure final stage of a steam turbine according to an eighth embodiment. FIG. 10 is a diagram illustrating an airfoil of a stationary blade according to a ninth embodiment. It is a figure which shows the airfoil of the stationary blade concerning Example 10. FIG. It is a figure which shows the stator blade which concerns on Example 11, Comprising: (a) is an airfoil, (b) has shown the cross-sectional shape of the arched leaf | plate spring before incorporating in a cavity. FIG. 10 is a diagram illustrating an airfoil of a stationary blade according to a twelfth embodiment. It is a figure which shows the other Example of a plate-shaped spring member, Comprising: (a) is a side view, (b) is a principal part enlarged view of (a). It is a graph which shows the relationship between board thickness and attenuation | damping.

Explanation of symbols

1, 1B, 1C Steam turbine 18, 18B, 18C Stage 19, 19B, 19C Blade group 20, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20J, 20K Stator blade 24 Abdominal surface 25 Abdominal side member (abdominal side) Part)
26 Back 27 Back member (back side)
28a, 28c Slit 30 Inner shroud 32 Blade root ring 36 Front edge 38 Rear edge 40, 40a, 40c Cavity 44 Corrugated leaf spring (plate spring member, biasing member, sliding member)
46a, 46c, 46e Front side top portions 48a, 48c, 48e, 48g Back side top portion 52 C-shaped leaf spring (plate spring member, biasing member, sliding member)
60 Bow leaf spring (plate spring member, biasing member, sliding member)
70, 72, 74 U-shaped leaf spring (plate spring member, biasing member, sliding member)
110 Damping material 120 Solid stationary vane 130 Rib (partition wall)
131 Damping material 140 Bow leaf spring (plate spring member, biasing member, sliding member)
141 Bow leaf spring (plate spring member, biasing member, sliding member)
150 Bow leaf spring (plate spring member, biasing member, sliding member)

Claims (17)

A stationary blade used in a steam turbine, in which a cavity is formed, and a slit is formed to communicate the cavity and the outside.
A stationary blade characterized in that a sliding contact member capable of sliding contact from the cavity to the inner surface of the blade is provided. The stationary blade according to claim 1,
Having a ventral part that is a part of the ventral side of the cavity and a dorsal part that is a part of the dorsal side of the cavity;
The sliding member is provided between the abdomen and the dorsal side, and is in contact with at least one of the abdomen and the dorsal side. The stationary blade according to claim 2,
The slidable contact member is a urging member that urges the abdominal side portion and the back side portion outward in the blade thickness direction. The stationary blade according to claim 3,
The urging member is a plate blade member that has a plate shape extending in the blade width direction and is a plate spring member that presses the abdominal side portion and the back side portion by an elastic force caused by bending. The stationary blade according to claim 4,
The plate-like spring member has a corrugated cross section, and a corrugated top is in contact with the abdomen and the dorsal side. The stationary blade according to claim 4,
The plate-like spring member has a substantially C-shaped cross section, and a C-shaped open end is in contact with one of the abdomen and the back, and a C-shaped base is in contact with the other. Static vane characterized by. The stationary blade according to claim 4,
The plate-like spring member has an arcuate cross section, and has an arcuate end in contact with either the ventral part or the dorsal part, and an arcuate base in contact with the other. Static wing. The stationary blade according to claim 4,
Two plate-like spring members having a bow-shaped cross section are arranged along the blade thickness direction, and the back surfaces of the base portions of the plate-like spring members are configured to be in sliding contact with each other. Characteristic stationary blade. The stator blade according to claim 7 or 8,
A stationary blade having a split structure or a slit structure in which an end portion of a plate spring member is divided into a plurality of plates in a plate thickness direction. The stationary blade according to claim 4,
The plate-shaped spring member has a U-shaped cross section, and a U-shaped arm portion is in contact with the abdominal side portion and the back side portion. The stationary blade according to any one of claims 4 to 10,
The ventral and dorsal sides are joined together at the front and back edges,
The stationary blade is characterized in that the plate-like spring member is coupled to one of the ventral side portion and the back side portion. The stationary blade according to any one of claims 4 to 11,
A vane characterized in that a damping material is provided in a cavity partitioned by a plate-like spring member and not communicating with the outside through a slit.   Provided substantially perpendicular to the average warp line of the wing, is provided with a plate-like partition wall that divides a cavity formed inside into a cavity on the leading edge side and a cavity on the trailing edge side, and on the trailing edge side A stationary blade, characterized in that a damping material is filled in the cavity.   A steam turbine, wherein the stationary blades according to any one of claims 1 to 13 are arranged at a predetermined interval in a circumferential direction of the rotor shaft. A steam turbine according to claim 14,
A steam turbine characterized by a mixture of solid stationary blades. A steam turbine according to claim 15, comprising:
A steam turbine in which the stationary blades and the solid stationary blades according to any one of claims 1 to 13 are alternately arranged. A steam turbine according to claim 14,
A steam turbine, wherein a plurality of types of stationary blades having different natural frequencies are arranged.

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