JP2015096730A - Turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an advanced turbine capable of reducing leakage amount of steam in clearances on tip ends of rotor blades or stator blades.SOLUTION: A turbine according to the present invention includes: a partition-plate outer ring 11 provided on an inner wall surface of a casing and having an annular groove 111 formed therein for storing a tip shroud 52; and a plurality of seal fins 12A, 12B, and 12C provided to protrude radially from a bottom surface 111a of the annular groove 111 for forming a very small clearance 13A between the seal fins 12A, 12B, and 12C and the tip shroud 52. The first seal fin 12A provided most upstream among the seal fins 12A, 12B, and 12C is located downstream of a radial end surface (radial wall surface) 522a, which is located most upstream, of the tip shroud 52, and a dead-water-region filling portion 99 is provided to be formed in a portion of the bottom surface 111a separate upstream from the first seal fin 12A and to include a pair of inclined surfaces K1 and K2 facing upstream and downstream, respectively.

Description

  The present invention relates to a turbine used in, for example, a power plant, a chemical plant, a gas plant, a steel mill, a ship, and the like.

Conventionally, as a kind of steam turbine, a casing, a shaft body (rotor) rotatably provided inside the casing, a stationary blade fixedly disposed on an inner peripheral portion of the casing, and a downstream side of the stationary blade One having a plurality of stages of moving blades radially provided on a shaft body is known. This steam turbine is roughly classified into an impulse turbine and a reaction turbine depending on the operation method. An impulse turbine is one in which a moving blade rotates only by an impact force received from steam.
In the impulse turbine, the stationary blade has a nozzle shape, and the steam that has passed through the stationary blade is injected to the moving blade, and the moving blade rotates only by the impact force received from the steam. On the other hand, the reaction turbine has the same shape as the moving blade, and the moving blade is affected by the impact force received from the steam passing through the stationary blade and the reaction force against the expansion of the steam generated when passing through the moving blade. Is what rotates.

  By the way, in such a steam turbine, a gap having a predetermined width is formed in the radial direction between the tip portion of the rotor blade and the casing, and also between the tip portion of the stationary blade and the shaft body. A gap having a predetermined width is formed in the direction. A part of the steam flowing in the axial direction of the shaft body leaks to the downstream side through the clearance between the tip portions of the rotor blades and the stationary blades. Here, the steam leaking downstream from the gap between the moving blade and the casing does not give impact force or reaction force to the moving blade, so that the driving blade is rotated regardless of whether it is an impulse turbine or a reaction turbine. Little contribution as power. In addition, the steam leaking downstream from the gap between the stationary blade and the shaft body does not change its speed and does not expand even if it exceeds the stationary blade, so regardless of whether it is an impulse turbine or a reaction turbine, It hardly contributes as a driving force for rotating the moving blade on the downstream side. Therefore, in order to improve the performance of the steam turbine, it is important to reduce the amount of steam leakage in the gap between the tip portions of the moving blades and the stationary blades.

  Therefore, seal fins are conventionally used as means for preventing steam from leaking from the gaps at the tips of the rotor blades and the stationary blades. For example, when this seal fin is used at the tip of a moving blade, it is provided so as to protrude from one of the moving blade and the casing and to form a minute gap between the other.

  Further, in the steam turbine, the corner of the casing is formed in a curved shape in a cross section along the axial direction so that stress concentration caused by the thermal expansion of the casing does not occur in the corner formed by the wall surface of the casing. Is conventionally known (see, for example, FIG. 2 of Patent Document 1). Here, the curved shape of the casing corner is generally an arc shape having a radius of about 1 mm.

JP 2000-0773702 A

  However, there is a strong demand for improving the performance of steam turbines, and there is a demand for further reduction in the amount of steam leakage from a gap between a blade body such as a moving blade and a structure body such as a casing.

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a high-performance turbine in which the amount of steam leakage in the gaps between the tip portions of the moving blades and stationary blades is reduced. is there.

  In order to achieve the above object, the present invention employs the following means. That is, the turbine according to the first aspect of the present invention includes a casing, a shaft body rotatably provided in the casing, a stationary blade held by the casing, and a motion provided in the shaft body. A blade, a tip shroud provided on the tip side of the rotor blade, a partition plate outer ring provided on an inner wall surface of the casing and having an annular groove for accommodating the tip shroud, and a diameter from a bottom surface of the annular groove A plurality of seal fins provided so as to protrude in the direction and forming minute gaps between the tip shroud and a first seal fin provided on the most upstream side of the plurality of seal fins. The tip shroud is located on the downstream side of the end surface in the radial direction located on the most upstream side, and is formed in a portion of the bottom surface that is spaced upstream from the first seal fin. Is provided with a dead water filling unit having a pair of inclined surfaces facing upstream and downstream, respectively.

  In the turbine according to the second aspect of the present invention, the turbine according to the first aspect includes a dead water area filling portion formed at a corner between the surface facing the upstream side of the first seal fin and the bottom surface. Furthermore, you may provide.

  Further, in the turbine according to the third aspect of the present invention, the turbine according to the first or second aspect is provided at a corner between the side surface facing the upstream side of the first seal fin and the bottom surface in the annular groove. You may further provide with the formed dead water area filling part.

  The turbine according to the fourth aspect of the present invention includes a casing, a shaft body rotatably provided inside the casing, a stationary blade held by the casing, and a motion provided in the shaft body. A blade, a tip shroud provided on the tip side of the rotor blade, a partition plate outer ring provided on an inner wall surface of the casing and having an annular groove for accommodating the tip shroud, and a diameter from a bottom surface of the annular groove A plurality of seal fins provided so as to protrude in the direction and forming a minute gap between the tip shroud and downstream between the pair of adjacent seal fins on the outer peripheral surface of the tip shroud A step is formed so that the side rises one step radially outward from the upstream side, and is formed at a portion of the bottom surface between the pair of seal fins. Comprising a dead water filling unit having a pair of inclined surfaces facing is.

  Further, in the turbine according to the fifth aspect of the present invention, the turbine according to the fourth aspect is formed at a corner portion between a surface facing the upstream side of the downstream seal fin and the bottom surface of the pair of seal fins. You may further provide the made dead water area filling part.

  In the turbine according to the sixth aspect of the present invention, the turbine according to the fourth or fifth aspect is a corner between a surface facing the downstream side of the upstream-side seal fin and the bottom surface of the pair of seal fins. You may further provide the dead water area filling part formed in the part.

  According to the turbine of the present invention, the amount of fluid leakage in the gap between the blade tip and the structure can be reduced.

It is a schematic sectional drawing which shows the steam turbine which concerns on the 1st reference example of this invention. FIG. 2 is a partially enlarged cross-sectional view in which the periphery of a tip portion of a moving blade in FIG. 1 is enlarged. It is a figure explaining the contraction flow effect of peeling vortex, Comprising: It is the elements on larger scale which expanded the front-end | tip part periphery of the 1st seal fin in FIG. It is a schematic sectional drawing which shows the front-end | tip part periphery of the moving blade of a 2nd reference example. It is a schematic sectional drawing which shows the front-end | tip part periphery of the moving blade of a 3rd reference example. It is a schematic sectional drawing which shows the front-end | tip part periphery of the moving blade of a 4th reference example. It is a schematic sectional drawing which shows the front-end | tip part periphery of the moving blade of a 5th reference example. It is the partial expanded sectional view which expanded the front-end | tip part periphery of the stationary blade of a 6th reference example. It is the partial expanded sectional view which expanded the front-end | tip part periphery of the 7th reference example. It is the partial expanded sectional view which expanded the front-end | tip part periphery of the stator blade of the 8th reference example. It is a partial expanded sectional view which shows the modification of an 8th reference example. It is a schematic sectional drawing which shows the front-end | tip part periphery of the moving blade of a 9th reference example, It is the figure expanded especially about the front-end | tip part of a 1st seal fin. It is a schematic sectional drawing which shows the front-end | tip part periphery of the moving blade of 1st Embodiment.

(First Reference Example)
Embodiments of the present invention will be described below with reference to the drawings. First, the configuration of the steam turbine according to the first reference example of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing a steam turbine 1 according to a first reference example.
The steam turbine 1 is provided in a hollow casing 10, a regulating valve 20 that adjusts the amount and pressure of steam S (fluid) flowing into the casing 10, and a casing 10 that is rotatably provided. A shaft body 30 for transmitting power to a machine such as a generator, an annular stationary blade group 40 held in the casing 10, an annular blade group 50 (blade) provided on the shaft body 30, and the shaft body 30 as an axis And a bearing portion 60 that is rotatably supported around.

  The casing 10 has an internal space hermetically sealed and a flow path for the steam S. A ring-shaped partition plate outer ring 11 (structure) into which the shaft body 30 is inserted is firmly fixed to the inner wall surface of the casing 10.

  A plurality of regulating valves 20 are attached to the inside of the casing 10, and each includes a regulating valve chamber 21 into which steam S flows from a boiler (not shown), a valve body 22, and a valve seat 23. When the valve seat 23 is separated from the valve seat 23, the steam flow path is opened, and the steam S flows into the internal space of the casing 10 through the steam chamber 24.

  The shaft body 30 includes a shaft main body 31 and a plurality of disks 32 extending in the radial direction from the outer periphery of the shaft main body 31. The shaft body 30 transmits rotational energy to a machine such as a generator (not shown).

The annular stationary blade group 40 surrounds the shaft body 30 and is provided at a predetermined interval in the circumferential direction, and a plurality of stationary blades 41 whose base end portions are respectively held by the partition plate outer ring 11 and the stationary blades 41. And a ring-shaped hub shroud 42 that connects the radial front ends to each other in the circumferential direction. The shaft 30 is inserted through the hub shroud 42 with a gap having a predetermined width in the radial direction.
The six annular stator blade groups 40 configured in this way are provided at predetermined intervals in the axial direction of the shaft body 30, and convert the pressure energy of the steam S into velocity energy, and are adjacent to the downstream side. It guides to the moving blade 51 side.

  The bearing portion 60 includes a journal bearing device 61 and a thrust bearing device 62, and supports the shaft body 30 in a rotatable manner.

The annular blade group 50 surrounds the shaft body 30 and is provided at a predetermined interval in the circumferential direction, and a plurality of blades 51 whose base ends are respectively fixed to the disk 32, and the radial direction of these blades 51 It has a ring-shaped tip shroud (not shown in FIG. 1) that connects the tip portions to each other in the circumferential direction.
The six annular blade groups 50 configured as described above are provided so as to be adjacent to the downstream side of the six annular stationary blade groups 40. Thereby, the annular stator blade group 40 and the annular rotor blade group 50, which are one set and one stage, are configured in a total of six stages along the axial direction.

  Here, FIG. 2 is a partially enlarged cross-sectional view in which the periphery of the tip portion of the rotor blade 51 in FIG. 1 is enlarged. As described above, the ring-shaped tip shroud 52 is disposed at the tip of the moving blade 51. The chip shroud 52 has a step-like cross-sectional shape, and includes three axial wall surfaces 521a, 521b, and 521c along the axial direction, and three radial wall surfaces 522a, 522b, and 522c along the radial direction. ing. Note that the cross-sectional shape of the tip shroud 52 is not limited to this reference example, and the design can be changed as appropriate.

  On the other hand, an annular groove 111 having a concave cross section is formed on the inner peripheral surface of the partition plate outer ring 11 shown in FIG. Then, three seal fins 12 are respectively provided on the bottom surface 111a of the annular groove so as to protrude in the radial direction.

  Here, of the three seal fins 12, the first seal fin 12A located on the most upstream side in the steam flow direction, that is, the axial direction, is provided slightly downstream from the radial wall surface 522a of the tip shroud 52, Between the tip and the axial wall surface 521a of the tip shroud 52, a minute gap 13A is formed in the radial direction. Of the three seal fins 12, the second seal fin 12 </ b> B located on the second upstream side is provided slightly downstream from the radial wall surface 522 b of the tip shroud 52, and its tip and the axial direction of the tip shroud 52 are provided. A minute gap 13B is also formed in the radial direction between the wall surface 521b. Further, among the three seal fins 12, the third seal fin 12 </ b> C located on the most downstream side is provided slightly downstream from the radial wall surface 522 c of the tip shroud 52, and the tip thereof and the axial wall surface 521 c of the tip shroud 52. Between these, a minute gap 13C is formed in the radial direction. The length of the seal fin 12 configured as described above is shortened in the order of the first seal fin 12A, the second seal fin 12B, and the third seal fin 12C.

Note that the length, shape, installation position, number, and the like of the seal fins 12 are not limited to this reference example, and the design can be appropriately changed according to the cross-sectional shape of the tip shroud 52 and / or the partition plate outer ring 11. The dimension of the minute gap 13 is a safe range in which the seal fin 12 and the tip shroud 52 do not contact each other in consideration of the thermal elongation amount of the casing 10 and the moving blade 51, the centrifugal elongation amount of the moving blade, and the like. Of these, it is preferable to set the minimum value. In this reference example, the three minute gaps 13 are all set to the same size, but the minute gaps 13 may be set to different dimensions by the seal fins 12 as necessary.
Further, in this reference example, the seal fin 12 is provided so as to protrude from the outer ring 11 of the partition plate, and the minute gap 13 is formed between the tip shroud 52 and, conversely, the seal fin 12 protrudes from the tip shroud 52. The minute gap 13 may be formed between the outer ring 11 and the partition plate outer ring 11.

  Then, according to the configuration around the tip portion of the moving blade 51, three cavities C (spaces) are formed by the partition plate outer ring 11, the seal fins 12, and the tip shroud 52, as shown in FIG. ing.

  Here, among the three cavities C, the first cavity C1 located on the most upstream side in the axial direction is formed with the bottom surface 111a and the side surface 111b of the annular groove 111 and the first seal fin as shown in FIG. 12A, and the radial wall surface 522a and the axial wall surface 521a of the chip shroud 52 are formed. The first cavity C1 formed in this way has a substantially rectangular shape in a cross section along the axial direction. However, since the first seal fin 12A is provided slightly downstream from the radial wall surface 522a as described above, the widened portion 14 slightly widened in the axial direction is provided in the axially downstream portion of the first cavity C1. Is formed.

  As shown in FIG. 2, the two corners of the first cavity C1, more specifically, the corner formed by the bottom surface 111a and the side surface 111b of the annular groove 111, and the bottom surface 111a of the annular groove 111 and the first Dead water area filling portions 15 are respectively provided at corners formed by one seal fin 12A. The two dead water zone filling portions 15 are for filling and eliminating the dead water zone generated at the corners of the first cavity C1, and are inclined surfaces formed in a concave curve in a cross section along the axial direction thereof. K. As will be described later, this concave curve is a shape that follows the vortex of the steam S generated inside the first cavity C1, and in this reference example, has an arc shape with a radius of 5 mm or more. Therefore, the size of the dead water filling portion 15 is about 25 times or more in terms of the cross-sectional area compared with the arc-shaped portion having a radius of about 1 mm formed at the corner of the casing to prevent stress concentration as described above. It is the size of.

  In this reference example, the dead water area filling portion 15 is configured as a separate member from the partition plate outer ring 11, but the dead water area filling portion 15 may be configured integrally with the partition plate outer ring 11. Further, the position where the dead water area filling portion 15 is provided is not limited to the corner of the first cavity C1, and can be an arbitrary position where the dead water area is generated in the first cavity C1. Further, the shape of the inclined surface K is not limited to the arc shape as in the present reference example, but can be any shape according to the shape of the vortex of the steam S.

  In addition, among the three cavities C, the second cavity C2 located on the second upstream side in the axial direction includes a bottom surface 111a of the annular groove 111, a first seal fin 12A, as shown in FIG. The tip shroud 52 is formed by the axial wall surfaces 521a and 521b and the radial wall surface 522b, and the second seal fin 12B. The widened portion 16 that is slightly widened in the axial direction is also formed in the axially downstream portion of the second cavity C2 in the same manner as the first cavity C1. Also, two corners of the second cavity C2, more specifically, a corner formed by the bottom surface 111a of the annular groove 111 and the first seal fin 12A, and a bottom surface 111a of the annular groove 111 and the second seal fin 12B, The dead water filling portions 17 are also provided at the corners formed by the above. The roles and shapes of the two dead water zone filling portions 17 are the same as those of the dead water zone filling portion 15 of the first cavity C1.

  Further, among the three cavities C, the third cavity C3 located on the most downstream side in the axial direction includes a bottom surface 111a of the annular groove 111, a second seal fin 12B, a tip shroud, as shown in FIG. 52, the axial wall surfaces 521b and 521c, the radial wall surface 522c, and the third seal fin 12C. The widened portion 18 that is slightly widened in the axial direction is formed in the axially downstream portion of the third cavity C3 as well as the first cavity C1. Also, two corners of the third cavity C3, more specifically, a corner formed by the bottom surface 111a of the annular groove 111 and the second seal fin 12B, and a bottom surface 111a of the annular groove 111 and the third seal fin 12C, The dead water area filling portions 19 are also provided at the corners formed by the above. The roles and shapes of the two dead water zone filling portions 19 are the same as those of the dead water zone filling portion 15 of the first cavity C1.

  Next, the effect of the steam turbine 1 which concerns on a 1st reference example is demonstrated using FIG.1 and FIG.2. When the regulating valve 20 shown in FIG. 1 is opened, the steam S flows into the casing 10 from a boiler (not shown). The steam S is guided to the annular moving blade group 50 by the annular stationary blade group 40 of each stage, and the annular moving blade group 50 starts rotating. Thereby, the energy of the steam S is converted into rotational energy by the annular blade group 50, and this rotational energy is transmitted from the shaft body 30 that rotates integrally with the annular blade group 50 to a generator (not shown) or the like. Is done.

  At this time, as shown in FIG. 2, a part of the steam S that has passed through the annular stator blade group 40 does not contribute to the rotational drive of the annular rotor blade group 50, and thus the seal fin 12 and the annular rotor blade group 50 Leak to the downstream side through the minute gap 13 therebetween.

  The leakage of the steam S will be described in detail. As shown in FIG. 2, a part of the steam S flowing in the axial direction through the annular stationary blade group 40 flows into the first cavity C <b> 1 without colliding with the moving blade 51. The steam S that has flowed into the first cavity C1 collides with the radial wall surface 522a of the tip shroud 52, thereby forming a main vortex SU1 (vortex) that is counterclockwise in FIG. Then, a part of the main vortex SU1 is peeled off at the corner 52A of the chip shroud 52, so that in the widened portion 14 of the first cavity C1, the main vortex SU1 rotates in the direction opposite to the main vortex SU1, that is, in FIG. HU1 (vortex) is generated. The separation vortex HU1 exhibits a so-called contraction effect that reduces the amount of leakage of the steam S in the minute gap 13A between the first seal fin 12A and the tip shroud 52.

  Here, FIG. 3 is a diagram for explaining the contraction effect of the separation vortex HU1, and is a partially enlarged cross-sectional view in which the periphery of the front end portion of the first seal fin 12A in FIG. 2 is enlarged. The clockwise peeling vortex HU1 has a radially inward inertial force immediately before the minute gap 13A between the first seal fin 12A and the tip shroud 52. Therefore, the steam S leaking downstream through the minute gap 13A is pressed down by the inertial force of the separation vortex HU1, so that the width in the radial direction is reduced as shown by the one-dot chain line in FIG. As described above, the separation vortex HU1 has an effect of reducing the leak amount by compressing the steam S radially inward, that is, a contraction effect. In addition, the effect of the contraction flow increases as the inertial force of the separation vortex HU1 increases, that is, as the flow velocity of the separation vortex HU1 increases.

  Further, as shown in FIG. 2, the first cavity C1 is provided with a substantially arc-shaped dead water area filling portion 15 at the two corners along the flow of the main vortex SU1. Therefore, a dead water area, that is, an area that does not reach the main vortex SU1 does not occur at the corner of the first cavity C1. Thereby, it is possible to prevent the energy of the steam S from being lost due to the steam S forming the main vortex SU1 flowing into the dead water area. Then, the main vortex SU1 can be strengthened, and as a result, the separation vortex HU1 that separates from the main vortex SU1 can also be strengthened. As a result, the contraction effect of the separation vortex HU1 is greater than in the case where there is no dead water filling section 15, and the amount of steam S leaked in the minute gap 13A between the first seal fin 12A and the tip shroud 52 is reduced. be able to.

  Further, as shown in FIG. 2, the vapor S leaking from the minute gap 13A flows into the second cavity C2. The steam S collides with the radial wall surface 522b of the tip shroud 52 to form a counterclockwise main vortex SU2. Then, when a part of the main vortex SU2 is peeled off, a clockwise peeling vortex HU2 is generated in the widened portion 16 of the second cavity C2. Similar to the separation vortex HU1, the separation vortex HU2 also exhibits a contraction effect that reduces the amount of leakage of the steam S in the minute gap 13B between the second seal fin 12B and the tip shroud 52.

  Further, as shown in FIG. 2, the second cavity C <b> 2 is also provided with a substantially arc-shaped dead water area filling portion 17 at each of its two corners. Therefore, the main vortex SU2 can be strengthened similarly to the dead water zone filling portion 15 of the first cavity C1, and as a result, the separation vortex HU2 can also be strengthened. Thereby, compared with the case where there is no dead water area filling part 17, the contraction effect of exfoliation eddy HU2 becomes large, and the amount of leakage of steam S in minute gap 13B can be reduced.

  Further, as shown in FIG. 2, the vapor S leaking from the minute gap 13B flows into the third cavity C3. The steam S collides with the radial wall surface 522c of the tip shroud 52 to form a counterclockwise main vortex SU3. Then, when a part of the main vortex SU3 is peeled off, a clockwise peeling vortex HU3 is generated in the widened portion 18 of the third cavity C3. Similar to the separation vortex HU1, the separation vortex HU3 also exhibits a contraction effect that reduces the leakage amount of the steam S in the minute gap 13C between the third seal fin 12C and the tip shroud 52.

  Furthermore, as shown in FIG. 2, the third cavity C3 is also provided with a substantially arc-shaped dead water area filling portion 19 at its two corners. Therefore, the main vortex SU3 can be strengthened similarly to the dead water zone filling portion 15 of the first cavity C1, and as a result, the separation vortex HU3 can also be strengthened. Thereby, compared with the case where there is no dead water area filling part 19, the contraction effect of separation vortex HU3 becomes large, and the amount of leakage of steam S in minute gap 13C can be reduced.

  In this way, the leakage amount of the steam S can be minimized by reducing the leakage amount of the steam S by the contraction effect of the separation vortices HU1, HU2, and HU3 in the three cavities C1, C2, and C3. It has become. The number of cavities C along the axial direction is not limited to three, and an arbitrary number can be provided. Further, in this reference example, the dead water area filling section 15 is provided in the first cavity C, the dead water area filling section 17 is provided in the second cavity C2, and the dead water area filling section 19 is provided in the third cavity C3. It is not necessary to provide a dead water area filling part in C, and it is sufficient if at least one cavity C is provided with a dead water area filling part.

(Second reference example)
Next, the configuration of the steam turbine according to the second reference example of the present invention will be described. The steam turbine according to the present reference example differs from the steam turbine 1 of the first reference example in the position where the dead water region filling portion is provided in the cavity C formed around the tip portion of the rotor blade 51. Since other configurations are the same as those of the first reference example, the same reference numerals are used, and the description thereof is omitted here.

  FIG. 4 is a schematic cross-sectional view showing the periphery of the tip of the moving blade 51 of the second reference example. Similar to the first reference example, three cavities C are formed between the annular blade group 50 and the partition plate outer ring 11. Of the three cavities C, the first cavity C1 located on the most upstream side in the axial direction is not provided with a dead water filling portion. In FIG. 4, the same components as those in the first reference example are denoted by the same reference numerals as those in FIG.

  Further, as shown in FIG. 4, among the three cavities C, the second cavity C2 located on the second upstream side in the axial direction is provided with a dead water filling portion 70 at one corner thereof. It has been. The dead water filling portion 70 has a substantially arc-shaped inclined surface K in a cross section along the axial direction, and is provided at a corner formed by the axial wall surface 521a and the radial wall surface 522b of the chip shroud 52. Yes.

  Moreover, as shown in FIG. 4, among the three cavities C, the third cavity C3 located on the most downstream side in the axial direction is provided with a dead water filling portion 71 at one corner thereof. Yes. The dead water region filling portion 71 also has a substantially arc-shaped inclined surface K, and is provided at a corner formed by the axial wall surface 521b and the radial wall surface 522c of the tip shroud 52.

  Next, the effects of the steam turbine 1 according to the second reference example will be described focusing on differences from the first reference example. According to the configuration shown in FIG. 4, when the steam S leaking downstream through the minute gap 13A between the first seal fin 12A and the tip shroud 52 flows into the second cavity C2, the first reference example and Similarly, the main vortex SU2 and the separation vortex HU2 are formed. And this peeling vortex HU2 exhibits the contraction effect which reduces the leak amount of the vapor | steam S in the micro clearance gap 13B.

  Furthermore, as shown in FIG. 4, a dead water area filling portion 70 having a substantially arc-shaped inclined surface K is provided at one corner of the second cavity C2. Accordingly, the main vortex SU2 can be strengthened by preventing the loss of the energy of the steam S in the dead water area, and as a result, the separation vortex HU2 can also be strengthened. Thereby, compared with the case where there is no dead water area filling part 70, the contraction effect of the separation vortex HU2 is increased, and the leakage amount of the steam S in the minute gap 13B can be reduced.

  In addition, in the present reference example, the dead water filling portion 70 is provided at a corner formed by the axial wall surface 521a and the radial wall surface 522b of the chip shroud 52. Therefore, it is possible to alleviate the occurrence of stress concentration due to thermal elongation or elongation due to centrifugal force at the corners 52B and 52C of the tip shroud 52 formed by the axial wall surface 521a and the radial wall surface 522b and having a sharp shape. it can.

  Furthermore, as shown in FIG. 4, a dead water area filling portion 71 having a substantially arc-shaped inclined surface K is also provided at one corner of the third cavity C3. Therefore, since the separation vortex HU3 can be strengthened by strengthening the main vortex SU3, the leakage amount of the steam S in the minute gap 13C can be reduced as compared with the case where there is no dead water area filling portion 71. In addition, the dead water region filling portion 71 is provided at a corner formed by the axial wall surface 521b and the radial wall surface 522c of the tip shroud 52. Therefore, stress concentration caused by thermal elongation or elongation due to centrifugal force can be mitigated in the corners 52B and 52C of the tip shroud 52 having a sharp shape.

(Third reference example)
Next, the configuration of the steam turbine according to the third reference example of the present invention will be described. The steam turbine according to this reference example is also different from the steam turbine 1 of the first reference example in the position where the dead water area filling portion is provided in the cavity C formed around the tip of the moving blade 51. Since other configurations are the same as those of the first reference example, the same reference numerals are used, and the description thereof is omitted here.

  FIG. 5 is a schematic cross-sectional view showing the periphery of the tip of the moving blade 51 of the third reference example. Similar to the first reference example, three cavities C are formed between the annular blade group 50 and the partition plate outer ring 11. Of the three cavities C, the first cavity C1 located on the most upstream side in the axial direction is provided with dead water filling portions 15 at the same two corners as in the first reference example shown in FIG. It has been. In FIG. 5, the same components as those in the first reference example are denoted by the same reference numerals as those in FIG.

  Further, as shown in FIG. 5, among the three cavities C, the second cavity C2 positioned second upstream in the axial direction has the same two corners as the first reference example shown in FIG. 2. In addition, a dead water area filling portion 17 is provided, and a dead water area filling portion 70 is also provided at the same corner as in the second reference example shown in FIG.

  Further, as shown in FIG. 5, among the three cavities, the third cavity C3 located on the most downstream side along the axial direction also has a dead water area at the same two corners as the first reference example shown in FIG. Each of the filling portions 19 is provided, and a dead water filling portion 71 is also provided at the same corner as in the second reference example shown in FIG.

  Next, the effects of the steam turbine 1 according to the third reference example will be described focusing on the differences from the first reference example. According to the configuration shown in FIG. 5, the second cavity C <b> 2 is further provided with a dead water zone filling unit 70 in addition to the two dead water zone filling units 17, so that the energy of the steam S is compared with the first reference example. Can be further prevented from being lost in the dead water area. Thereby, since the main vortex SU2 can be further strengthened, the separation vortex HU2 can be further strengthened, and the leak amount of the steam S in the minute gap 13B can be further reduced as compared with the first reference example. In addition, for the third cavity C3, the amount of leakage of the steam S in the minute gap 13C can be further reduced than in the first reference example for the same reason as the second cavity C2.

  Furthermore, in the present reference example, by providing the dead water area filling portions 70 and 71 at the sharp corners 52B and 52C of the chip shroud 52, respectively, as in the second reference example, the heat shredding or the centrifugal force causes the It is possible to alleviate the occurrence of stress concentration at the location.

(4th reference example)
Next, the configuration of the steam turbine according to the fourth reference example of the present invention will be described. The steam turbine according to this reference example differs from the steam turbine 1 of the first reference example in the position and shape of the dead water region filling portion in the cavity C formed around the tip of the moving blade 51. . Since other configurations are the same as those of the first reference example, the same reference numerals are used, and the description thereof is omitted here.

  FIG. 6 is a schematic cross-sectional view showing the periphery of the tip of the moving blade 51 of the fourth reference example. Similar to the first reference example, three cavities C are formed between the annular blade group 50 and the partition plate outer ring 11. The three cavities C are each provided with a dead water area filling portion at the same corner as the third reference example shown in FIG. 5, but the shape of the inclined surface K of each dead water area filling portion is the third reference. It is different from the example. In FIG. 6, the same components as those in the first reference example are denoted by the same reference numerals as those in FIG.

More specifically, as shown in FIG. 6, among the three cavities C, the first cavity C1 located on the most upstream side in the axial direction includes the same two as the first reference example shown in FIG. A dead water filling portion 72 having an inclined surface K having a substantially elliptic arc shape is provided at the corner.
In addition, the second cavity C2 located on the second upstream side in the axial direction is also provided with a dead water filling portion 73 having an inclined surface K having a substantially elliptic arc shape at the same two corners as in the first reference example. In addition, a dead water filling portion 74 having an inclined surface K having a substantially elliptic arc shape is provided at the same corner as in the second reference example.
Further, the third cavity C3 located on the most downstream side in the axial direction is also provided with a dead water area filling portion 75 having an inclined surface K having a substantially elliptic arc shape at the same two corners as in the first reference example. A dead water filling portion 76 having an inclined surface K having a substantially elliptic arc shape is provided at the same corner as in the second reference example.

Next, the effects of the steam turbine 1 according to the fourth reference example will be described focusing on differences from the third reference example. According to the configuration shown in FIG. 6, all of the dead water filling portions 72 to 76 provided in the three cavities C have the inclined surface K having a substantially elliptic arc shape, so that the steam turbine 1 of the third reference example is achieved. In addition to the effect, depending on the shape of the three cavities C, there is an effect that the leak amount of the steam S in the minute gaps 13A, 13B, and 13C can be further reduced as compared with the third reference example.
This is because the main vortices SU1, SU2, SU3 generated in the three cavities C generally have a cross-sectional shape along the axial direction that is elliptical rather than a perfect circle. Therefore, the main vortices SU1, SU2, SU3. If the shape of the inclined surface K of the dead water region filling sections 72 to 76 is also substantially elliptical arc shape so as to more accurately follow the shape of the steam S, it is the third that steam S flows into the dead water region and its energy is lost. It is because it can prevent more reliably than a reference example.

  In addition, as shown in FIG. 6, in this reference example, the inclined surface K of the dead water filling portion 72, 73, 75 provided on the partition plate outer ring 11 side has a substantially elliptical arc shape that is vertically long in the radial direction. On the other hand, the inclined surfaces K of the dead water filling portions 74 and 76 provided on the tip shroud 52 side have a substantially elliptical arc shape that is vertically long in the axial direction. According to such a configuration, the main vortices SU1, SU2, and SU3 can be accurately guided and collided with the corners of the chip shroud 52, so that the separation directions of the separation vortices HU1, HU2, and HU3 coincide with the radial direction. Can be made. As a result, the separation vortices HU1, HU2, and HU3 have an inertial force in the radial direction immediately before the minute gaps 13A, 13B, and 13C, so that the contraction effect of the separation vortices HU1, HU2, and HU3 is increased. Can do. Note that it is possible to appropriately change the design of whether the inclined surfaces K of the dead water filling portions 72 to 76 are formed in a substantially elliptical arc shape that is vertically long in either the axial direction or the radial direction.

(5th reference example)
Next, the configuration of the steam turbine according to the fifth reference example of the present invention will be described. The steam turbine according to this reference example differs from the steam turbine 1 of the first reference example in the position and shape of the dead water region filling portion in the cavity C formed around the tip of the moving blade 51. . Since other configurations are the same as those of the first reference example, the same reference numerals are used, and the description thereof is omitted here.

  FIG. 7 is a schematic cross-sectional view showing the periphery of the tip of the moving blade 51 of the fifth reference example. Similar to the first reference example, three cavities C are formed between the annular blade group 50 and the partition plate outer ring 11. The three cavities C are each provided with a dead water area filling portion at the same corner as the third reference example shown in FIG. 5, but the shape of the inclined surface K of each dead water area filling portion is the third reference. It is different from the example. In FIG. 7, the same components as those in the first reference example are denoted by the same reference numerals as those in FIG.

More specifically, as shown in FIG. 7, among the three cavities C, the first cavity C1 located on the most upstream side in the axial direction includes two same as the first reference example shown in FIG. A dead water area filling portion 77 having a substantially linear inclined surface K is provided at the corner.
Also, in the second cavity C2 located upstream of the second surface along the axial direction, there is a dead water area filling portion 78 having a substantially linear inclined surface K at the same two corners as in the first reference example. In addition to being provided, a dead water area filling portion 79 having a substantially linear inclined surface K is provided at the same corner as in the second reference example.
Further, the third cavity C3 located on the most downstream side in the axial direction is also provided with a dead water area filling portion 80 having a substantially linear inclined surface K at the same two corners as in the first reference example. A dead water filling portion 81 having a substantially linear inclined surface K is provided at the same corner as in the second reference example.

  Next, the effects of the steam turbine 1 according to the fifth reference example will be described focusing on differences from the third reference example. According to the configuration shown in FIG. 6, all of the dead water filling parts 77 to 81 provided in the three cavities C have the substantially straight inclined surface K, so that the steam turbine 1 of the third reference example is achieved. In addition to the effect, there is an effect that the production of the dead water filling portions 77 to 81 can be simplified as compared with the third reference example. Specifically, when the dead water region filling portions 77 to 81 are configured as separate members from the partition plate outer ring 11 and the tip shroud 52, the processing work of the dead water region filling portions 77 to 81 can be facilitated. On the other hand, when the dead water region filling portions 77 to 81 are configured integrally with the partition plate outer ring 11 and the tip shroud 52, the shape of the mold for forming the partition plate outer ring 11 and the tip shroud 52 is simplified. be able to.

  In this reference example, the case where the dead water area filling portions 77 to 81 have only one substantially linear inclined surface K has been described as an example. However, the dead water area filling portions 77 to 81 have an approximately linear inclined surface K. You may have two or more. That is, the cross-sectional shape of the dead water area filling portions 77 to 81 is not limited to a triangle as in this reference example, and may be a polygon.

(Sixth reference example)
Next, the configuration of the steam turbine according to the sixth reference example of the present invention will be described. Compared with the steam turbine 1 of the first reference example, the steam turbine according to the present reference example is such that the position where the dead water region filling portion is provided is not the periphery of the tip portion of the moving blade 51 but the tip portion of the stationary blade 41. Is different. Since other configurations are the same as those of the first reference example, the same reference numerals are used, and the description thereof is omitted here. In this reference example, the annular stationary blade group 40 corresponds to the blade according to the present invention, and the shaft body 30 corresponds to the structure according to the present invention.

  FIG. 8 is a partial enlarged cross-sectional view in which the vicinity of the tip of the stationary blade 41 of the sixth reference example is enlarged. As described above, the ring-shaped hub shroud 42 is disposed at the tip of the stationary blade 41. Three seal fins 84 are provided on the outer peripheral surface 42a of the hub shroud 42 so as to protrude in the radial direction. Of the three seal fins 84, the first seal fin 84A provided on the most upstream side in the axial direction is substantially flush with the axial end surface 42b located at the most upstream portion in the axial direction of the hub shroud 42. It is provided to form.

  On the other hand, an annular groove 301 having a concave cross section is formed on the outer peripheral surface of the shaft body 30, and a portion having a small diameter due to the formation of the annular groove 301 is inserted into the hub shroud 42. Thereby, a minute gap 85 is formed in the radial direction between the bottom surface 301 a of the annular groove 301 and each seal fin 84.

  Note that the length, shape, installation position, number, and the like of the seal fins 84 are not limited to this reference example, and can be appropriately changed according to the cross-sectional shape of the hub shroud 42 and / or the shaft body 30. The dimension of the minute gap 85 is preferably set to a minimum value within a safe range where the seal fin 84 and the shaft body 30 do not contact each other. Further, in this reference example, the seal fin 84 is provided so as to protrude from the hub shroud 42 and the minute gap 85 is formed between the seal fin 84 and the shaft body 30, but conversely, the seal fin 84 protrudes from the shaft body 30. It may be provided and a minute gap 85 may be formed between the hub shroud 42 and the hub shroud 42.

  And according to the structure around the front-end | tip part of such a stationary blade 41, as shown in FIG. 8, the three cavities C are formed by the shaft body 30, the seal fin 84, and the hub shroud 42. As shown in FIG. Here, among the three cavities C, the fourth cavity C4 located on the most upstream side in the axial direction is provided with the bottom surface 301a and the side surface 301b of the annular groove 301 and the first seal fin as shown in FIG. 84A and the axial end surface 42b of the hub shroud 42 are formed. The fourth cavity C4 thus formed has a substantially rectangular shape with a cross section along the axial direction.

  As shown in FIG. 8, a dead water filling portion 86 is provided at one corner of the fourth cavity C4, more specifically at the corner formed by the bottom surface 301a and the side surface 301b of the annular groove 301. It has been. This one dead water region filling part 86 has a substantially elliptic arc-shaped inclined surface K in a cross section along the axial direction thereof.

  In addition, the role of the dead water area filling part 86 is the same as that of the first reference example. Further, the shape of the inclined surface K of the dead water filling section 86 is not limited to a substantially elliptic arc shape as in this reference example, but may be a substantially arc shape or a substantially linear shape. Further, in this reference example, the dead water filling portion 86 is provided only in the fourth cavity among the three cavities C, but the fifth cavity C5 located on the second upstream side or the sixth cavity located on the most downstream side. You may provide a dead water zone filling part also in the cavity C6. That is, the dead water region filling portion is also formed in the corner portion formed by the outer peripheral surface 42a of the hub shroud 42 and the second seal fin 84B, or in the corner portion formed by the outer peripheral surface 42a of the hub shroud 42 and the third seal fin 84C. May be provided.

  Next, operational effects of the steam turbine 1 according to the sixth reference example will be described. The steam S that has flowed into the casing 10 shown in FIG. 1 originally passes between the plurality of stationary blades 41 constituting the annular stationary blade group 40 and is guided to the annular moving blade group 50. A part of S leaks downstream through a minute gap 85 (85A, 85B, 85C) between the annular stationary blade group 40 and the shaft body 30.

  The leakage of the steam S will be described in detail. As shown in FIG. 8, part of the axially flowing steam S flows into the fourth cavity C <b> 4 without being guided downstream by the stationary blade 41. The steam S that has flowed into the fourth cavity C4 collides with the axial end face 42b of the hub shroud 42, thereby forming, for example, a clockwise main vortex SU4 in FIG. Here, since the first seal fins 84A are provided so as to form substantially the same surface as the axial end surface 42b of the hub shroud 42, the main vortex SU4 generates a separation vortex at the corner 42A of the hub shroud 42. There is nothing. However, in this reference example, since the main vortex SU4 rotates clockwise, the main vortex SU4 has a radially outward inertial force immediately before the minute gap 85A. Accordingly, the main vortex SU4 exerts a contraction effect that reduces the leak amount by compressing the steam S leaking downstream through the minute gap 85A.

  Further, as shown in FIG. 8, the fourth cavity C4 is provided with a dead water area filling portion 86 having a substantially elliptic arc shape along the flow of the main vortex SU4 at one corner thereof. Therefore, the dead water area generated in the fourth cavity C4 can be reduced, and loss of energy due to the flow of the steam S into the dead water area can be reduced. As a result, the main vortex SU4 can be strengthened as compared with the case where there is no dead water filling section 86, and as a result, the contraction effect of the main vortex SU4 is increased, and the amount of leakage of the steam S in the minute gap 85A is reduced. be able to.

(Seventh reference example)
Next, the configuration of the steam turbine according to the seventh reference example of the present invention will be described. The steam turbine according to the present reference example differs from the steam turbine according to the sixth reference example in the shape of the cavity located on the most upstream side in the axial direction. Since the other configuration is the same as that of the sixth reference example, the same reference numerals are used and description thereof is omitted here.

  FIG. 9 is a partially enlarged cross-sectional view in which the vicinity of the tip of the stationary blade 41 of the seventh reference example is enlarged. Similar to the sixth reference example, three cavities C are formed between the annular stationary blade group 40 and the shaft body 30. However, of the three cavities C, the seventh cavity C7 located on the most upstream side in the axial direction, that is, the portion upstream of the first seal fin 84A drops stepwise in the radial direction from the downstream portion. That is, in this reference example, it is formed so as to be positioned radially inside. In the sixth reference example, the seal fin 84 can be provided so as to protrude from the shaft body 30 instead of the hub shroud 42 side. However, in this reference example, the seal fin 84 is provided on the hub shroud 42 side. Is an essential configuration and cannot be provided in the shaft body 30. It is not limited to the vicinity of the tip of the stationary blade 41, and a seal fin 84 is provided so as to protrude from the tip shroud 52 constituting the rotor blade 51, and a portion upstream of the seal fin 84 is arranged in a radial direction from a downstream portion. You may form so that it may step down, ie, may be located in the radial direction outer side.

  And as shown in FIG. 9, the dead water area filling parts 87 and 88 are each provided in the two corners of the 7th cavity C7. More specifically, a dead water region filling portion 87 is provided at a corner portion formed by the bottom surface 301a and the side surface 301b of the annular groove 301, and a corner portion formed by the bottom surface 301a and the step surface 301c is filled with a dead water region. A portion 88 is provided. These two dead water zone filling portions 87 and 88 each have a substantially elliptic arc-shaped inclined surface K in a cross section along the axial direction thereof.

  Next, the effects of the steam turbine 1 according to the seventh reference example will be described focusing on differences from the sixth reference example. In the present reference example, as shown in FIG. 9, the first seal fin 84 </ b> A is provided so as to protrude from the hub shroud 42, so that the position where the minute gap 85 </ b> A is formed is a position close to the shaft body 30. Then, the seventh cavity C7 on the upstream side from the minute gap 85A is formed to be stepped down from the eighth cavity C8 and the ninth cavity C9 on the downstream side.

According to such a configuration, as shown in FIG. 9, the main vortex SU5 that rotates clockwise inside the seventh cavity C7 passes through the minute gap 85A and reaches further downward (inward in the radial direction).
Accordingly, in the main vortex SU5 of the present reference example, the turning center of the main vortex SU5 approaches the minute gap 85A as compared with the case where there is no stepping down as in the sixth reference example shown in FIG. Accordingly, the radial velocity of the main vortex SU5 in the vicinity of the minute gap 85A is faster when there is a step than when there is no step, and the contraction effect of the main vortex SU5 is increased. The leak amount of the steam S can be further reduced.
Further, in this reference example, dead water filling portions 87 and 88 are provided at two corners of the seventh cavity C7, so that only one corner of the fourth cavity C4 is provided as in the sixth reference example. Compared with the case where the dead water area filling part 86 is provided, the dead water area can be further reduced and the main vortex SU5 can be further strengthened.
Thereby, this reference example has the effect that the leak amount of the vapor | steam S in 85 A of micro gaps can be reduced further compared with the 6th reference example.

(Eighth reference example)
Next, the configuration of the steam turbine according to the eighth reference example of the present invention will be described. The steam turbine according to this reference example is different in the shape of each cavity from the steam turbine of the sixth reference example. Since the other configuration is the same as that of the sixth reference example, the same reference numerals are used and description thereof is omitted here.

  FIG. 10 is a partially enlarged cross-sectional view in which the periphery of the tip portion of the stationary blade 41 of the eighth reference example is enlarged. As in the seventh reference example, three cavities C are formed between the annular stator blade group 40 and the shaft body 30. However, among the three cavities C, the tenth cavity C10 located on the most upstream side has the same configuration as the seventh cavity C7 of the seventh reference example, but the eleventh cavity C11 and the twelfth cavity located on the downstream side thereof. The configuration of C12 is different from the eighth cavity C8 and the ninth cavity C9 of the seventh reference example.

More specifically, as shown in FIG. 10, the bottom surface 301a of the annular groove 301 has a downstream side along the axial direction at a position between the first seal fin 84A and the second seal fin 84B adjacent to each other. A stepped portion 89 is formed so as to step inward in the radial direction from the upstream side.
As a result, a widened portion 90 that is slightly widened in the radial direction is formed in the axially downstream portion of the eleventh cavity C11. Further, on the downstream side of the stepped portion 89, the radial height position of the bottom surface 301a is a height position substantially equal to the bottom surface 301a forming the tenth cavity C10. The bottom surface 301a on the downstream side of the stepped portion 89 may be at a different height from the bottom surface 301a that forms the tenth cavity C10.

  And as shown in FIG. 10, the dead water area filling parts 87 and 88 are each provided in the two corners of 10th cavity C10 similarly to the 7th reference example. In addition, a dead water area filling portion 82 and a dead water area filling portion 83 are provided at three corners of the eleventh cavity C11. More specifically, the corner formed by the outer peripheral surface 42a of the hub shroud 42 and the first seal fin 84A and the corner formed by the outer peripheral surface 42a and the second seal fin 84B are filled with dead water. Each part 82 is provided. Furthermore, a dead water filling portion 83 is provided at a corner formed by the step portion 89 and the bottom surface 301a.

  Next, the effects of the steam turbine 1 according to the eighth reference example will be described focusing on differences from the seventh reference example. According to the configuration shown in FIG. 10, the clockwise main vortex SU5 is formed inside the tenth cavity C10, similarly to the seventh cavity C7 of the seventh reference example, and has the same effect as the seventh reference example. Play.

  Further, according to the configuration shown in FIG. 10, the vapor S flowing from the tenth cavity C10 to the eleventh cavity C11 through the minute gap 85A forms a counterclockwise main vortex SU6 inside the eleventh cavity C11. . Then, a part of the main vortex SU6 is peeled off at the corner portion of the step portion 89, whereby a clockwise peeling vortex HU4 is generated. Here, since this separation vortex HU4 has a radially inward inertial force immediately before the minute gap 85B between the second seal fin 84B and the shaft body 30, it exerts a large contraction effect. . Therefore, compared to the case where the stepped portion 89 is not formed in the eleventh cavity C11 and only the counterclockwise main vortex SU6 is generated therein, this reference example is formed at the tip portion of the second seal fin 84B. There is an effect that the leakage amount of the steam S in the minute gap 85B can be further reduced.

  Further, as shown in FIG. 10, the eleventh cavity C11 is provided with a dead water area filling portion 82 along the flow of the main vortex SU6 at its two corners, and at one corner with a separation vortex. A dead water area filling portion 83 is provided along the flow of the HU 4. Therefore, it is possible to reduce the loss of energy by flowing into the dead water area for both the main vortex SU6 and the separation vortex HU4. As a result, both the main vortex SU6 and the separation vortex HU4 can be strengthened as compared with the case without the dead water area filling portions 82 and 83, so that the leakage amount of the steam S in the minute gap 85B can be reduced.

In this reference example, the stepped portion 89 is formed so that the downstream side is stepped radially inward from the upstream side along the axial direction. On the contrary, as shown in FIG. The step portion 91 may be formed so as to rise one step radially outward from the upstream side. In this case, a widened portion 92 that is slightly widened in the axial direction is formed in the axially downstream portion of the eleventh cavity C11.
As in the configuration shown in FIG. 10, the corner formed by the outer peripheral surface 42a of the hub shroud 42 and the first seal fin 84A and the corner formed by the outer peripheral surface 42a and the second seal fin 84B are A dead water area filling section 82 is provided. Further, a dead water filling portion 100 is provided at a corner formed by the step portion 91 and the bottom surface 301a.

  According to such a configuration, the vapor S flowing from the tenth cavity C10 to the eleventh cavity C11 through the minute gap 85A also forms the main vortex SU7 inside the eleventh cavity C11. A part of the main vortex SU7 is peeled off at the corner portion of the step portion 91, whereby a clockwise peeling vortex HU5 is generated. Thereby, even when the stepped portion 91 is formed, the same effect as that obtained when the stepped portion 89 is formed can be obtained.

  Furthermore, as shown in FIG. 11, the eleventh cavity C11 is provided with dead water filling portions 82 at two corners, so that the energy loss of the main vortex SU7 can be reduced as in the configuration of FIG. In addition, since the dead water filling portion 100 is provided at one corner, the energy loss of the separation vortex HU5 can also be reduced. Thereby, according to the structure shown in FIG. 11, compared with the case where there is no dead water area filling parts 82 and 100, the leak amount of the vapor | steam S in the micro clearance gap 85B can be reduced.

(Ninth Reference Example)
Next, the configuration of the steam turbine according to the ninth reference example of the present invention will be described. The steam turbine according to the present reference example differs from the steam turbine 1 of the first reference example in the position where the dead water region filling portion is provided in the cavity C formed around the tip portion of the rotor blade 51. Here, FIG. 12 is a schematic sectional view showing the periphery of the tip portion of the moving blade 51 of the ninth reference example, and is an enlarged view of the tip portion of the first seal fin 93 in particular. In addition, since it is the same as that of a 1st reference example about structures other than the 1st seal fin 93, it uses the same code | symbol and abbreviate | omits description here.

  In the present reference example, the first seal fin 93 includes a fin main body portion 931 and a space limiting portion 932 formed wider than the fin main body portion 931. Thus, the first cavity C1 upstream from the first seal fin 93 has a widened portion 94 that is slightly widened in the axial direction at the downstream side in the axial direction. In addition, a dead water area filling portion 95 is provided at a corner portion of the widened portion 94, more specifically at a corner portion formed by the fin main body portion 931 and the space limiting portion 932.

  Next, the effects of the steam turbine 1 according to the ninth reference example will be described focusing on differences from the first reference example. According to the configuration shown in FIG. 12, the counterclockwise main vortex SU <b> 1 formed in the first cavity C <b> 1 is partially peeled off at the corner portion of the tip shroud 52, so that the inside of the widened portion 94 is A clockwise peeling vortex HU1 is generated. Here, the separation vortex HU1 collides with the space restricting portion 932 and the fin main body portion 931, and the flow direction thereof is guided, whereby the flow of the vortex flow is strengthened. Furthermore, since the dead water region filling portion 95 is provided at the corner of the widened portion 94, it is possible to reduce the loss of energy of the steam S due to the separation vortex HU1 flowing into the dead water region. Thereby, compared with the case where there is no dead water area filling portion 95, the separation vortex HU1 can be strengthened to increase the contraction effect thereof, so that the amount of leakage of the steam S in the minute gap 13A can be reduced.

(First embodiment)
Next, the configuration of the steam turbine according to the first embodiment of the present invention will be described. The steam turbine according to the present embodiment differs from the steam turbine 1 of the first reference example in the position where the dead water region filling portion is provided in the cavity C formed around the tip of the moving blade 51.
Since other configurations are the same as those of the first reference example, the same reference numerals are used, and the description thereof is omitted here.

  FIG. 13 is a schematic cross-sectional view showing the periphery of the tip portion of the rotor blade 51 of the first embodiment. Similar to the first reference example, three cavities C are formed between the annular blade group 50 and the partition plate outer ring 11. Here, in this embodiment, the separation distance in the axial direction from the seal fins 12A, 12B, 12C to the radial wall surfaces 522a, 522b, 522c is set longer than that in the first reference example. Accordingly, the widened portions 96, 97, and 98 of the three cavities C1, C2, and C3 are formed wider than the first reference example.

  Of the three cavities C, the first cavity C1 located on the most upstream side in the axial direction is provided with a dead water area filling portion 15 at two corners similarly to the first reference example. Yes. More specifically, the dead water filling portion 15 is formed at the corner formed by the bottom surface 111a and the side surface 111b of the annular groove 111 and at the corner formed by the bottom surface 111a of the annular groove 111 and the first seal fin 12A. Is provided.

  Furthermore, in this embodiment, in addition to the two corners, the first cavity C1 is provided with a dead water area filling portion 99 at an intermediate position between the two corners of the bottom surface 111a of the annular groove 111. . The dead water filling portion 99 has two inclined surfaces K1 and K2, and one inclined surface K1 has the other inclined surface K2 so as to follow the flow of the main vortex SU1 generated in the first cavity C1. Are formed so as to follow the flow of the separation vortex HU1 generated in the widened portion 96 of the first cavity C1. Similarly to the first cavity C1, the second cavity C2 and the third cavity C3 are also provided with dead water filling portions 17 and 19 at the two corners, respectively, and between the two corners of the bottom surface 111a. A dead water area filling section 99 is provided at each position.

  Next, the operational effects of the steam turbine 1 according to the first embodiment will be described focusing on differences from the first reference example. According to the configuration shown in FIG. 13, since the widened portions 96, 97, 98 are formed wider than the first reference example as described above, the separation vortices HU1, HU2, HU3 reach the bottom surface 111a of the annular groove 111. It will be about the size.

Here, in the first cavity C1 in the present embodiment, a total of three dead water area filling portions 15, 15, 99 are provided, so that both the main vortex SU1 and the separation vortex HU1 flow into the dead water area. The loss of the energy of the steam S can be reduced. Therefore, the separation vortex HU1 can be strengthened indirectly by strengthening the main vortex SU1, and the separation vortex HU1 can also be strengthened directly. As a result, the contraction effect of the separation vortex HU1 is increased as compared with the case where there is no dead water area filling portion 15, 15, 99, so that the amount of leakage of the steam S in the minute gap 13A can be reduced.
Similarly, in the second cavity C2 and the third cavity C3 in the present embodiment, a total of three dead water area filling portions 17, 17, 99 and 19, 19, 99 are respectively provided, and the first cavity C1 and Since the same effect is obtained, the leak amount of the steam S in the minute gaps 13B and 13C can be reduced.

  The various shapes, combinations, operation procedures, and the like of the constituent members shown in the above-described embodiments are merely examples, and various changes can be made based on design requirements and the like without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Steam turbine 10 Casing 11 Partition outer ring (structure)
111 annular groove 111a bottom surface 111b side surface 12 seal fin 12A first seal fin 12B second seal fin 12C third seal fin 13 minute gap 13A minute gap 13B minute gap 13C minute gap 14 widened portion 15 dead water area filling portion 16 widened portion 17 dead Water area filling section 18 Widening section 19 Dead water area filling section 20 Regulating valve 21 Regulating valve chamber 22 Valve body 23 Valve seat 24 Steam chamber 30 Shaft body (structure)
301 annular groove 301a bottom surface 301b side surface 301c stepped surface 31 shaft main body 32 disk 40 annular stationary blade group (blade)
41 Stator blade 42 Hub shroud 42A Corner portion 42a Outer peripheral surface 42b Axial end surface 50 Annular blade group (blade)
51 Rotor blade 52 Chip shroud 52A Corner portion 521a Axial wall surface 521b Axial wall surface 521c Axial wall surface 522a Radial wall surface 522b Radial wall surface 522c Radial wall surface 60 Bearing portion 61 Journal bearing device 62 Thrust bearing device 70 Dead water zone filling portion 71 Dead water area filling section 73 Dead water area filling section 73 Dead water area filling section 74 Dead water area filling section 75 Dead water area filling section 77 Dead water area filling section 78 Dead water area filling section 79 Dead water area filling section 80 Dead water area filling section 81 Dead water area filling section 82 Dead water area filling section 83 Dead water area filling section 84 Seal fin 84A First seal fin 84B Second seal fin 84C Third seal fin 85 Minute gap 85A Minute gap 85B Minute gap 85C Minute gap 86 Dead water area filling section 87 Dead water area filling section 88 Dead water area filling section 89 Stepped portion 90 Widened portion 91 Stepped portion 92 Widening portion 93 First seal fin 931 Fin body portion 932 Space limiting portion 94 Widening portion 95 Dead water region filling portion 96 Widening portion 97 Widening portion 98 Widening portion 99 Dead water region filling portion C Cavity C1 First cavity C10 Tenth cavity C11 Eleventh Cavity C12 12th cavity C2 2nd cavity C3 3rd cavity C4 4th cavity C5 5th cavity C6 6th cavity C7 7th cavity C8 8th cavity C9 9th cavity HU1 peeling vortex HU2 peeling vortex HU3 peeling vortex HU4 peeling vortex HU5 Separation vortex K Inclined surface K1 Inclined surface K2 Inclined surface S Steam SU1 Main vortex SU2 Main vortex SU3 Main vortex SU4 Main vortex SU5 Main vortex SU6 Main vortex SU7 Main vortex

Claims (6)

A casing,
A shaft body rotatably provided in the casing;
A stationary blade held by the casing;
A moving blade provided on the shaft body;
A tip shroud provided on the tip side of the blade,
A partition plate outer ring provided on an inner wall surface of the casing and formed with an annular groove for accommodating the chip shroud;
A plurality of seal fins provided so as to protrude in a radial direction from the bottom surface of the annular groove and forming a minute gap with the tip shroud;
With
Of the plurality of seal fins, the first seal fin provided on the most upstream side is located on the downstream side of the radial end surface located on the most upstream side of the tip shroud,
A turbine comprising a dead water filling portion formed at a portion of the bottom surface that is spaced upstream from the first seal fin and having a pair of inclined surfaces facing the upstream side and the downstream side.   2. The turbine according to claim 1, further comprising a dead water filling portion formed at a corner portion between a surface facing the upstream side of the first seal fin and the bottom surface.   The turbine according to claim 1, further comprising a dead water area filling portion formed at a corner portion between a side surface facing the upstream side of the first seal fin in the annular groove and the bottom surface. A casing,
A shaft body rotatably provided in the casing;
A stationary blade held by the casing;
A moving blade provided on the shaft body;
A tip shroud provided on the tip side of the blade,
A partition plate outer ring provided on an inner wall surface of the casing and formed with an annular groove for accommodating the chip shroud;
A plurality of seal fins provided so as to protrude in a radial direction from the bottom surface of the annular groove and forming a minute gap with the tip shroud;
With
Between the pair of adjacent seal fins on the outer peripheral surface of the tip shroud, a step is formed such that the downstream side rises one step radially outward from the upstream side,
A turbine provided with a dead water zone filling portion formed at a portion of the bottom surface between the pair of seal fins and having a pair of inclined surfaces respectively facing the upstream side and the downstream side.   The turbine according to claim 4, further comprising a dead water region filling portion formed at a corner portion between a surface facing the upstream side of the downstream seal fin and the bottom surface of the pair of seal fins.   6. The turbine according to claim 4, further comprising a dead water region filling portion formed at a corner portion between a surface facing the downstream side of the upstream-side seal fin and the bottom surface of the pair of seal fins.

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