JPWO2015068279A1 - Axial flow turbine - Google Patents

Abstract

In an axial turbine including a rotating body (109, 112, 102, 118) and a stationary part (103, 101, 111), a rotor disk (112) constituting a part of the rotating body is provided with a rotating shaft (100) direction. A guide in which a plurality of guide channels inclined in the direction opposite to the rotation direction of the previous rotating body from the upstream side to the downstream side of the balance hole are formed on the downstream side of the balance hole (120) formed in parallel. A flow path member (130) is provided. Thereby, the turning speed of the leakage flow passing between the rotating body and the stationary part can be reduced, and the unstable vibration of the rotating body can be effectively suppressed.

Description

  The present invention relates to an axial flow turbine such as a steam turbine or a gas turbine, and more particularly, to an axial flow turbine having a clearance channel formed between an outer peripheral surface of a rotating body and an inner peripheral surface of a stationary part.

  A steam turbine, which is one of rotary fluid machines, generally includes a casing, a rotor rotatably provided in the casing, a stationary blade row provided on the inner peripheral side of the casing, and an outer peripheral side of the rotor. And a moving blade row disposed downstream of the stationary blade row in the rotor axial direction. When the working fluid passes through the stationary blade row (specifically, between the stationary blades) in the main channel, the internal energy of the working fluid is converted into kinetic energy. That is, the working fluid is accelerated. Thereafter, when the working fluid passes through the moving blade row (specifically, between the moving blades), the kinetic energy of the working fluid is converted into the rotational energy of the rotor. In other words, the working fluid acts on the rotor blade row to rotate the rotor.

  A steam turbine has a diaphragm structure in which a stationary blade row is fixed by an annular body (hereinafter referred to as a diaphragm outer ring and a diaphragm inner ring) provided on the outer peripheral side and the inner peripheral side. Some of them have a rotor disk structure fixed by a rotor disk protruding in the direction. In such a structure, a gap channel (hereinafter referred to as a diaphragm seal portion as appropriate) is formed between the inner peripheral surface of the diaphragm inner ring and the outer peripheral surface of the rotor facing the inner ring surface. Most of the working fluid flows in the main flow path and passes through the stationary blade row, but part of the working fluid (leakage flow) passes through the space between the main ring and the diaphragm inner ring and the rotor disk. Leakage into the diaphragm seal will cause turbine loss.

Some steam turbines are provided with an annular blade cover on the outer peripheral side of the blade row. In such a structure, a gap channel (hereinafter, referred to as a bucket seal portion as appropriate) is formed between the outer circumferential surface of the bucket cover and the inner circumferential surface of the casing facing the bucket cover. Most of the working fluid flows in the main flow path and passes through the rotor blade row. However, a part of the working fluid (leakage fluid) leaks from the main flow path to the blade seal part, causing the turbine loss. Become.
In order to improve the turbine efficiency by suppressing the leakage flow as described above, a labyrinth seal is generally provided in the gap flow path. The labyrinth seal is composed of multiple stages of seal fins and steps that are spaced apart in the rotor axial direction. A contraction flow and an expansion flow are generated at the tip of the seal fin, and the amount of leakage is reduced by the pressure loss. It is to reduce.

  In addition, the labyrinth seal is required to reduce the leakage flow and to minimize the fluid force that causes unstable vibration.

  The fluid force that causes unstable vibration of the rotating body will be described with reference to FIG. FIG. 12 is a schematic cross-sectional view of the rotating body 1 and the stationary part 2 as seen from the axial direction. A gap channel 3 is formed between the rotating body 1 and the stationary part 2. The rotating body 1 rotates in the direction indicated by the arrow 4 in the drawing. The rotating body 1 is not concentric with the stationary part 2 due to manufacturing tolerances, gravity, or vibration during rotation, and is slightly eccentric as shown in the figure. That is, the center 8 of the rotating body is shifted from the center 7 of the stationary part 2 by the eccentric amount e. Further, the leakage flow passing through the gap flow path 3 has a speed component parallel to the axial direction, and also has a turning speed component 9 due to the rotation of the rotating body 1. Due to the eccentricity of the rotating body 1 and the turning speed component 9, an uneven pressure distribution 5 is generated in the circumferential direction inside the gap 3. Due to this non-uniform pressure distribution 5, forces Fx and Fy perpendicular to the rotation axis act on the rotating body 1. In particular, the fluid force Fy acting perpendicularly to the eccentric direction causes the rotating body 1 to sway, and if it becomes greater than the damping force acting on the rotating body 1, unstable vibration is generated.

  As a technique for reducing the fluid force, for example, a method of providing a swirl prevention plate (swirl break) for reducing the swirl speed at the labyrinth seal inlet is known. The aforementioned fluid force Fy, which causes unstable vibration, increases as the swirl speed of the leakage flow increases. Therefore, the fluid force can be reduced by providing a swirl prevention plate at the seal inlet.

  Moreover, there exists a thing of patent document 1 as a technique of reducing the fluid force which generate | occur | produces especially in a diaphragm seal part. In Patent Document 1, a rotor hole is provided with a balance hole penetrating in the axial direction, the balance hole is inclined toward the inner peripheral side with respect to the rotor rotational axis direction, and the balance hole outlet is disposed on the inner peripheral side from the inlet. In addition, a configuration is shown in which a guide plate that induces a flow in the direction opposite to the rotor rotation direction is arranged for each balance hole outside the balance hole outlet. By arranging the balance hole outlet on the inner peripheral side, the swirling speed of the flow flowing out from the balance hole can be reduced, and the swirling speed of the flow flowing into the diaphragm seal portion can be reduced. As a result, the fluid force generated at the diaphragm seal portion can be reduced. In addition, by arranging a guide plate that induces a flow in the direction opposite to the rotor rotation direction outside the balance hole outlet, the swirling speed of the flow flowing out of the balance hole can be further reduced, and the fluid force can be reduced. Further reduction can be achieved.

JP2013-113222A

  The method of providing a swirl prevention plate (swirl break) to reduce the swirl speed at the labyrinth seal inlet is effective in reducing the fluid force, but it is necessary to secure a region for placing the swirl prevention plate at the seal inlet Therefore, the number of seal fins that can be arranged in the seal portion is reduced. As a result, the leakage flow increases and the turbine efficiency decreases.

  In the configuration described in Patent Document 1, in which the balance hole that is inclined toward the inner peripheral side with respect to the rotor rotation axis direction is formed in the rotor disk, it may be difficult to process the balance hole. In particular, in the case of a steam turbine composed of large and multistage blade rows, the rotor disk is often formed integrally with the rotor, and a large number of rotor disks corresponding to each paragraph are arranged at narrow intervals in the axial direction. It is relatively easy to machine a hole parallel to the rotation axis direction on such a rotor disk. However, when machining holes inclined with respect to the rotation axis, it is necessary to use complex multi-axis machine tools. In addition, when an inclined balance hole is provided, the hollow portion of the rotor disk is formed to expand in the radial direction, which may reduce the strength of the rotor disk.

  Further, in the configuration in which a guide plate that induces a flow in the direction opposite to the rotor rotation direction is disposed outside the balance hole outlet described in Patent Document 1, the guide plate is disposed outside the rotor disk. When the relative position in the axial direction of the inner ring of the diaphragm and the rotor disk changes due to the difference in thermal expansion (the difference in the amount of thermal expansion deformation between the stationary part and the rotating body), the guide plate faces it in the axial direction. There is a possibility of contact with the inner ring of the diaphragm, which greatly impairs the reliability of the turbine. In the first place, in the configuration where the guide plate is provided outside the balance hole outlet, the guide plate that rotates together with the rotor disk induces a swirling flow in the rotating direction, so the swirling speed of the flow that flows out of the balance hole is reduced. It is not possible to obtain a sufficient effect.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an axial turbine that can effectively suppress unstable vibration caused by leakage flow in a gap between a rotating body and a stationary part.

  In order to achieve the above object, the present invention provides a rotor and at least one rotor disk that is provided so as to rotate integrally with the rotor and has a first through hole formed in parallel with the rotation axis direction of the rotor. A plurality of rotor disks, a plurality of rotor blade rows provided on the outer periphery of the plurality of rotor disks, a casing for storing the rotor, the plurality of rotor disks, and the plurality of rotor blade rows, and the rotor A plurality of stator blade rows provided on the inner peripheral surface of the casing so as to be alternately arranged with the plurality of rotor blade rows in the rotation axis direction, and provided on each inner ring side of the plurality of stator blade rows A plurality of diaphragm inner rings, and a plurality of guide flows provided on the inner downstream side of the first through hole and inclined in the direction opposite to the rotational direction of the previous rotor from the upstream side to the downstream side of the first through hole. Characterized in that but with a guide passage member formed.

  According to the present invention, in an axial flow turbine, it is possible to effectively suppress unstable vibration of a rotating body caused by a leakage flow in a gap between the rotating body and a stationary part.

It is a cross-sectional schematic diagram which shows a part of steam turbine which concerns on the 1st Embodiment of this invention. It is a schematic perspective view of the guide flow path member with which the steam turbine which concerns on the 1st Embodiment of this invention is equipped. It is a schematic cross-sectional perspective view of the guide flow path member with which the steam turbine which concerns on the 1st Embodiment of this invention is equipped. 1 is a schematic perspective view of a rotor disk provided in a steam turbine according to a first embodiment of the present invention. It is a cross-sectional schematic diagram of the guide flow path member which concerns on the 1st Embodiment of this invention. It is a cross-sectional schematic diagram of the baffle plate which concerns on a prior art. It is a cross-sectional schematic diagram of the baffle plate which concerns on the application example of a prior art. It is a schematic perspective view of the guide flow path member with which the steam turbine which concerns on the 2nd Embodiment of this invention is equipped. It is a schematic sectional perspective view of the guide flow path member with which the steam turbine which concerns on the 2nd Embodiment of this invention is equipped. It is a schematic perspective view of the rotor disk with which the steam turbine which concerns on the 3rd Embodiment of this invention is equipped. It is a schematic perspective view of the guide flow path member with which the steam turbine which concerns on the 3rd Embodiment of this invention is equipped. It is the cross-sectional schematic diagram which looked at the rotary body and the stationary part from the axial direction.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment in which the present invention is applied to a diaphragm seal portion of a steam turbine will be described with reference to the drawings. In addition, in each figure, when there are a plurality of components having the same shape and the same kind of material, the same reference numerals are given to the components.

-First embodiment-
FIG. 1 is a schematic cross-sectional view showing a part of a steam turbine according to the present invention. In FIG. 1, the steam turbine includes a rotating body composed of a rotor 109 and the like that rotates about a rotating shaft 100, and a stationary part composed of a substantially cylindrical casing 103 that houses the rotating body 1. .

  A plurality of rotor disks 112 that rotate integrally with the rotor 109 are formed on the outer circumferential surface of the rotor 109 so as to protrude in the radial direction. On the outer periphery of the rotor disk 112, a plurality of moving blades 102 are fixed radially with respect to the rotating shaft 100 to form a substantially annular moving blade row. On the other hand, on the inner peripheral surface of the casing 103, a plurality of stationary blades 101 are fixed radially with respect to the rotating shaft 100 to form a substantially annular stationary blade row. As shown in FIG. 1, the stationary blade rows and the moving blade rows are alternately arranged in the direction of the rotation axis 100. A substantially annular diaphragm inner ring 111 is provided on the inner ring side of the stationary blade row.

  A diaphragm seal portion 115 is formed between the inner peripheral surface of the diaphragm inner ring 111 and the outer peripheral surface of the rotor 109 facing the diaphragm inner ring 111. The diaphragm seal portion 115 is a rabin rinse seal configured by fins 115 a provided on the outer peripheral surface of the rotor 109 and convex portions 115 b formed on the inner peripheral side of the diaphragm inner ring 111.

  On the other hand, a substantially uniform moving blade cover 118 is provided on the outer peripheral side of the moving blade 102 in the circumferential direction, and the moving blade is disposed between the outer peripheral surface of the moving blade cover 118 and the casing inner peripheral surface facing it. A seal 116 is formed. The blade seal portion 116 is a labyrinth seal constituted by fins 116 a provided on the outer peripheral side of the blade cover 118 and convex portions 116 b formed on the casing 103.

  The rotor disk 112 is formed with a balance hole 120 (first through hole) penetrating in parallel with the rotation axis 100 direction of the rotor 109. The balance hole 120 is a substantially cylindrical through hole, and is discretely formed at the same radius with respect to the rotating shaft 100 (see FIG. 4).

  Inside the casing 103, steam (working fluid) heated in advance by a boiler (not shown) or the like flows in a direction indicated by an arrow 11 in a main flow path passing through the stationary blade 101 and the moving blade 102. The steam flows through the stationary blade 101 and the moving blade 102, and the internal energy of the steam is extracted as rotational energy through the moving blade 102, the rotor disk 112, and the rotor 109. If the combination of the stationary blade 101 and the moving blade 102 is a single stage, only one stage and its periphery are shown in FIG. 1, but in order to efficiently recover the internal energy of the steam, generally in the axial direction A plurality of stages are arranged.

  A part of the main flow indicated by the arrow 11 passes through the blade seal portion 116 and the diaphragm seal portion 115 as a leakage flow indicated by arrows 12a and 12b.

  In the balance hole 120, a downstream flow as indicated by an arrow 13 is generated due to a pressure difference between the upstream side and the downstream side of the rotor disk 112. The balance hole 120 serves to reduce the axial fluid force (thrust force) acting on the rotor 109 by relaxing the pressure difference between the upstream side and the downstream side of the rotor disk 112 by the flow 13. Furthermore, since the leakage flow 13a flowing out from the diaphragm seal portion 115 does not return to the main flow 11 and passes through the balance hole 120, the turbulence generated in the main flow 11 can be reduced, and the turbine efficiency can be improved. Can do.

  A guide channel member 130 is provided on the downstream side of the balance hole 120. A schematic perspective view of the guide channel member 130 is shown in FIG. In FIG. 2, the guide channel member 130 includes a substantially hollow cylindrical holding case 132 that can be inserted into the balance hole 120, and a plurality of rectifying plates 131 disposed inside the holding case 132. A convex portion 140 is formed on the outer periphery of the holding case 132 for positioning when inserted into the balance hole 120, and is fixed to the end of the holding case 132 inside the balance hole 120. For this purpose, a fixing member 143 having a hooking pawl 142 at the tip is attached. A schematic cross-sectional perspective view with the upper half of the guide channel member 130 removed is shown in FIG. In FIG. 3, the plurality of rectifying plates 131 are inclined to deflect the flow flowing out from the balance hole 120. In addition, by configuring a plurality of guide channels by the plurality of rectifying plates 131, the ratio of the channel cross-sectional area to the axial channel length per guide channel can be reduced, and the effect of deflecting the flow can be improved. it can.

  FIG. 4 is a schematic perspective view of the rotor disk 112 and shows a method of attaching the guide channel member 130 to the balance hole 120. In the figure, the rotor 109 and the rotor disk 112 rotate in the direction indicated by the arrow 15. The guide channel member 130 is inserted into the balance hole 120 from the downstream side of the rotor disk 112 as indicated by an arrow 138. On the rotor disk surface on the downstream side of the balance hole 120, a notch 141 that fits with the convex portion 140 is provided, whereby the guide channel member 130 is positioned inside the balance hole 120.

  FIG. 5 shows a state inside the balance hole 120 where the guide channel member 130 is arranged. In this figure, the rotor disk 112 rotates in the direction indicated by the arrow 15. When the guide channel member 130 is inserted into the balance hole 120, the claw 142 provided at the tip of the fixing member 143 is hooked on the rotor disk surface upstream of the balance hole 120, and the guide channel member 130 is moved to the balance hole 120. Fixed internally. As described above, a flow from the upstream side to the downstream side indicated by the arrow 13 is generated inside the balance hole 120. However, the plurality of rectifying plates 131 have a rotational direction 15 from the upstream side to the downstream side of the balance hole 120. Inclined in the opposite direction. As a result, the flow that has passed through the guide flow path member 130 is imparted with a turning speed component opposite to the rotation direction 15 and flows out in the direction indicated by the arrow 16. The flow direction indicated by arrows 13 and 16 is the flow direction when observed from above the rotating rotor disk (when viewed in a coordinate system rotating with the rotor disk 112). When viewed in a stationary state (stationary coordinate system), since the turning speed corresponding to the rotational speed of the rotor disk 112 is added to the flow indicated by the arrows 13 and 16, respectively, the flow is inclined in the turning direction. . That is, the swirl speed in the rotation direction 15 of the flow flowing out of the balance hole 120 is reduced by the plurality of rectifying plates 131.

  In the present embodiment, the guide channel member 130 is positioned and fixed by the projection 140 and the claw 142 provided at the tip of the fixing member 143. However, the present invention is not limited to this. The flow channel member 130 may be welded to the downstream side inside the balance hole 120. In this case, the convex part 140 and the fixing member 143 are unnecessary. The guide channel member 130 can be manufactured by welding a plurality of rectifying plates inside the holding case 132, but is not limited to this. For example, the guide channel member 130 may be manufactured by cutting out from a cylindrical member. Good.

  The effect of this embodiment will be described below in comparison with the prior art.

  For example, FIG. 6 shows a configuration in which a guide plate that induces a flow in the direction opposite to the rotor rotation direction on the outside downstream side of the balance hole described in Patent Document 1. As shown in FIG. 6, when the guide plate 150 rotates together with the rotor disk 112, a flow in the direction of the arrow 18 is induced between the rotor disk 112 and the diaphragm inner ring 111 as viewed in the stationary system coordinate system. Thereby, the effect of the guide plate 150 is offset, and the swirl component of the flow flowing out of the balance hole 120 cannot be sufficiently reduced. Further, since the guide plate 150 is disposed outside the rotor disk 112, when the relative position in the axial direction of the diaphragm inner ring 111 and the rotor disk 112 changes due to the difference in thermal expansion between the rotating body of the turbine and the stationary part, the guide plate The possibility of 150 coming into contact with the diaphragm inner ring 111 facing in the axial direction increases, and the reliability of the turbine is greatly impaired.

  As an application example of the configuration shown in FIG. 6, it is conceivable to arrange the guide plate 150 inside the balance hole 120 as shown in FIG. 7, but in this case, the flow 13 is guided as shown by the arrow 19. It is throttled at the tip of the plate 150 and flows out as a contracted flow, and the swirl velocity component in the direction opposite to the rotation direction cannot be sufficiently induced.

  On the other hand, according to the present embodiment, as shown in FIG. 5, a plurality of rectifying plates 131 are provided in the balance hole, so that the arrow 18 in FIG. 6 is interposed between the rotor disk 112 and the diaphragm inner ring 111. Without inducing the flow in the rotational direction shown, a rotational speed component in the direction opposite to the rotational direction can be effectively applied, and the rotational speed in the rotational direction at the exit of the balance hole 120 can be reduced. As a result, the swirling speed of the flow flowing into the diaphragm seal portion 115 can be reduced. As a result, the fluid force generated in the diaphragm seal portion 115 can be reduced, and the unstable vibration of the rotor can be effectively suppressed. can do.

-Second embodiment-
A steam turbine according to the second embodiment will be described with reference to FIGS. Note that parts similar to those in the first embodiment are denoted by reference numerals in the 200th series (the last two digits are the same) instead of the 100th series, and differences from the first embodiment will be mainly described. .

  FIG. 8 is a schematic perspective view of the guide channel member 230 corresponding to FIG. 2 of the first embodiment. As shown in FIG. 8, the configuration of the guide channel member 230 is the same as that of the first embodiment except that a plurality of guide channels are formed by a plurality of through holes 245 instead of a plurality of guide plates. It is the same.

  FIG. 9 is a schematic cross-sectional perspective view with the upper half removed to show the inside of the guide channel member 230. The plurality of through holes 245 are inclined in order to deflect the flow on the inner downstream side of the balance hole.

  In the present embodiment, the plurality of through holes 245 are inclined cylindrical holes, but are not limited thereto, and may be inclined rectangular holes, for example.

  The effect of this embodiment will be described below.

  According to the present embodiment, as in the first embodiment, the flow generated in the diaphragm seal portion is effectively imparted to the flow that has flowed out of the balance hole by applying a swirl velocity component in the direction opposite to the rotation direction. The physical strength can be reduced, and the unstable vibration of the rotor can be effectively suppressed.

  In addition, since the plurality of guide channels are configured by the plurality of through holes 245, the number of guide channels is smaller than in the case where the plurality of guide channels are configured by the plurality of rectifying plates 131 in the first embodiment. Therefore, the ratio of the channel cross-sectional area to the axial channel length per guide channel is reduced, and the effect of deflecting the flow can be further improved.

-Third embodiment-
With reference to FIG. 10, the steam turbine which concerns on 3rd Embodiment is demonstrated. The same reference numerals in the 300s are attached to the same parts as in the first embodiment instead of the 100s, and the difference from the first embodiment will be mainly described. .

  FIG. 10 is a schematic perspective view showing a state where the rotor blade 302 is fixed to the rotor disk 312. In the steam turbine, as shown in FIG. 10, in order to counteract the centrifugal force acting on the moving blade 302 during the rotation of the rotor, an uneven moving blade fastening portion 380 formed at the root portion of the moving blade 302; In some cases, a structure in which a corresponding concave and convex rotor disk fastening portion 381 formed on the circumference of the rotor disk 312 is fitted is used. In the rotor disk 312 shown in FIG. 10, a groove 382 is further formed on the inner peripheral side of the rotor disk fastening part 381, and the rotor disk 312 is rotated with the rotor disk 312 in a state where the rotor blade 302 is fitted. A fastening portion flow path 320 (a first through hole) that penetrates in parallel with the axial direction is formed. In the fastening part flow path 320, the flow toward the downstream is generated by the pressure difference between the upstream side and the downstream side of the rotor disk, similarly to the balance hole 120 of the first embodiment. That is, in the present embodiment, the same effect as that of the balance hole can be obtained by providing the fastening portion flow path 320 instead of the balance hole. Specifically, the pressure difference between the upstream side and the downstream side of the rotor disk 312 can be relaxed, and the axial fluid force (thrust force) acting on the rotor 309 can be reduced. Furthermore, since the leaked flow that flows out from the diaphragm seal portion does not return to the main flow side and passes through the fastening portion flow path 320, the turbulence that occurs in the main flow can be reduced, and the turbine efficiency can be improved. it can.

  Further, a guide channel member 330 is provided on the downstream side in the rotation axis direction on the downstream side in the fastening portion channel 320. The guide channel member 330 is inserted and fixed in the fastening portion channel 320 as indicated by an arrow 338. A schematic perspective view of the guide channel member 330 is shown in FIG. In FIG. 11, the shape of the holding case 332 is different from that of the first embodiment, but includes a plurality of rectifying plates 331 inclined from the upstream side toward the downstream side in the direction opposite to the rotor rotation direction 15. Are the same. That is, as in the first embodiment, the rotational speed in the rotational direction of the flow that has passed through the fastening portion flow path 320 is reduced.

  The effect of this embodiment will be described below.

  According to the present embodiment, the hydrodynamic force generated in the diaphragm seal portion can be reduced by reducing the swirling speed of the flow that passes through the fastening portion flow path 320 and flows into the diaphragm seal portion. Unstable vibration can be effectively suppressed. That is, even when the fastening portion flow path is provided instead of the balance hole, the unstable vibration of the rotor can be effectively suppressed.

  Further, since the groove portion 382 constituting the fastening portion flow path 320 can be processed at the time of processing the rotor disk fastening portion 381, the manufacturing process of the rotor disc can be reduced compared with the case of processing the balance hole. .

  The present invention is not limited to the first and second embodiments described above, and can be freely changed and improved without departing from the gist of the invention.

  In the first and second embodiments, the steam turbine has been described as an example. However, in the present invention, a gap flow path through which a part of the working fluid passes is formed between the rotating body and the stationary part. It can also be applied to other axial turbines.

11 Main flow 12a, 12b Leakage flow 15 Rotating direction 100 Rotating shaft 101 Stator blade 102, 302 Rotor blade 103 Casing 109, 309 Rotor 111 Diaphragm inner ring 112, 312 Rotor disk 115 Diaphragm seal portion 115a Fin 115b Protruding portion 116 Rotor blade seal portion 116a Fin 116b Protrusion 118 Rotor cover 120 Balance hole (first through hole)
130, 230, 330 Guide channel members 131, 331 Rectifying plates 132, 332 Holding case 140 Protruding portion 142 Claw 143 Fixing member 150 Guide plate 245 Through hole (second through hole)
320 Fastening channel (first through hole)
380 Rotor blade fastening portion 381 Rotor disk fastening portion 382 Groove portion

Claims (5)

A rotor,
A plurality of rotor disks including at least one rotor disk having a first through hole provided so as to rotate integrally with the rotor and formed in parallel with a rotation axis direction of the rotor;
A plurality of blade rows provided on the outer periphery of the plurality of rotor disks;
A casing for storing the rotor, the plurality of rotor disks, and the plurality of blade rows;
A plurality of stationary blade rows provided on an inner peripheral surface of the casing so as to be alternately arranged with the plurality of blade rows in the rotation axis direction of the rotor;
A plurality of diaphragm inner rings provided on the inner ring side of each of the plurality of stationary blade rows;
A guide channel provided on the inner downstream side of the first through hole and formed with a plurality of guide channels inclined in the direction opposite to the rotation direction of the previous rotor from the upstream side to the downstream side of the first through hole. An axial turbine comprising: a member; The axial turbine according to claim 1,
The axial flow turbine according to claim 1, wherein the first through hole is a balance hole formed in the at least one rotor disk. The axial turbine according to claim 1,
The axial flow turbine according to claim 1, wherein the first through hole is formed in a fastening portion that fixes the plurality of blade rows to the at least one rotor disk. In the axial turbine according to any one of claims 1 to 3,
The axial flow turbine is characterized in that the guide flow path is composed of a plurality of rectifying plates inclined from the upstream side to the downstream side of the through hole in the direction opposite to the rotation direction of the previous rotor. In the axial turbine according to any one of claims 1 to 3,
The plurality of guide passages are constituted by a plurality of second through holes inclined in the direction opposite to the rotation direction of the rotor from the upstream side to the downstream side of the first through hole. Turbine.

Images