Stator vane segment, stator vane ring, and steam turbine

Abstract

An embodiment of the present application relates to a stator vane segment including: a first stator vane and a second stator vane that are adjacent in a circumferential direction; an outer wheel side shroud; a groove portion provided to an inner peripheral surface of the outer wheel side shroud, located between a first pressure surface of the first stator vane and a second suction surface of the second stator vane, and extending from the first pressure surface toward the second suction surface; and at least one suction portion provided in the groove portion or provided so as to communicate with the groove portion and communicate with an inner space of the outer wheel side shroud. A weighted average position of the at least one suction portion is closer to a second intersection position at which the groove portion intersects the second suction surface than to a first intersection position at which the groove portion intersects the first pressure surface.

Description

Technical Field

[0001] This invention relates to a stationary blade segment, a stationary blade ring, and a steam turbine.

[0002] This application claims priority based on Japanese Patent Application No. 2024-021606 filed with the Japan Patent Office on February 16, 2024, the contents of which are incorporated herein by reference. Background Technology

[0003] In the low-pressure section of the blade array of a steam turbine, performance degradation (wet steam loss) caused by condensate (drain) generated in wet steam or erosion of the moving blades caused by condensate impacting the moving blades located on the downstream side can easily occur.

[0004] Therefore, a steam turbine with a mechanism for removing condensate from wet steam has been developed (for example, see Patent Document 1).

[0005] For example, the steam turbine described in Patent Document 1 is configured to recover condensate from a hole provided at the bottom of a condensate recess (groove) extending circumferentially along the inner circumferential surface of the blade root ring (outer wheel side shroud) to a space, i.e., a condensate chamber, located radially outward of the hole.

[0006] Previous technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-002937 Summary of the Invention

[0009] The technical problem to be solved by the invention

[0010] In the steam turbine described in the aforementioned patent document, a condensate recess extending circumferentially is provided with holes for condensate recovery at relatively uniform intervals along the circumferential direction.

[0011] However, the inventors, through in-depth research, determined that the condensate adhering to the inner circumferential surface of the blade root ring tends to flow from the ventral side of one stationary blade to the back side of another stationary blade on the inner circumferential surface of the blade root ring, due to the influence of the secondary flow of steam flowing between the ventral side of one adjacent stationary blade and the back side of another stationary blade in the circumferential direction, rather than flowing into the interior of the condensate recess.

[0012] Therefore, if holes for condensate recovery are provided at relatively uniform intervals along the circumference in the condensate recess extending along the circumference, it may be difficult to improve the efficiency of condensate recovery from the holes.

[0013] In view of the above, at least one embodiment of the present invention aims to improve the recovery efficiency of condensate generated in the wet steam of a steam turbine.

[0014] means for solving technical problems

[0015] (1) The stationary blade segment according to at least one embodiment of the present invention comprises:

[0016] First stationary blade;

[0017] The second stationary blade is adjacent to the first stationary blade; and

[0018] The outer wheel side guard is for mounting the first blade-shaped portion of the first stationary blade and the second blade-shaped portion of the second stationary blade.

[0019] The first ventral surface of the first leaf-shaped portion faces the second back surface of the second leaf-shaped portion.

[0020] The stationary blade segment also features:

[0021] A groove, disposed on the inner circumferential surface of the outer wheel side guard, located between the first ventral surface and the second rear surface, extending from the first ventral surface toward the second rear surface; and

[0022] At least one suction unit is disposed within the groove or configured to connect with the groove and communicate with the internal space of the outer wheel side guard.

[0023] The first intersection position is defined as the position where the groove intersects with the first ventral surface when viewed from the blade height direction of the first blade-shaped portion, or the position where the extension line of the groove extending towards the first ventral surface intersects with the first ventral surface.

[0024] The second intersection point is defined as the position where the groove intersects the second back surface when viewed from the blade height direction of the second blade-shaped portion, or the position where the extension line of the groove extending towards the second back surface intersects the second back surface.

[0025] The weighted average position of at least one inhalation part, which is the weighted average position of the center positions of each of the inhalation parts in the direction from the first intersection position toward the second intersection position using the opening area of ​​the inhalation part, is closer to the second intersection position than the first intersection position.

[0026] (2) In the stator blade ring according to at least one embodiment of the present invention, a plurality of stator blade segments configured as described above (1) are arranged circumferentially on the outer wheel side guard.

[0027] (3) The steam turbine according to at least one embodiment of the present invention has a stator ring with the configuration described in (2) above.

[0028] Invention Effects

[0029] According to at least one embodiment of the present invention, the recovery efficiency of condensate generated in the wet steam of a steam turbine can be improved. Attached Figure Description

[0030] Figure 1 It is a schematic cross-sectional view illustrating the general structure of a steam turbine involved in some embodiments.

[0031] Figure 2 This is a schematic cross-sectional view of the stationary blade segment and housing involved in some embodiments, viewed from the circumferential direction.

[0032] Figure 3 This is a diagram used to illustrate the secondary flow of steam.

[0033] Figure 4 yes Figure 5A The sectional view along the IV-IV direction.

[0034] Figure 5 Figure 5A This is a diagram showing the stationary blade segment of one embodiment viewed from the radial inside.

[0035] Figure 5 Figure 5B This is a diagram showing the stationary blade segment as viewed from the radial inside in some other embodiments.

[0036] Figure 5 Figure 5C This is a diagram showing the stationary blade segment as viewed from the radial inside in some other embodiments.

[0037] Figure 5 Figure 5D This is a diagram showing the stationary blade segment as viewed from the radial inside in some other embodiments.

[0038] Figure 5 Figure 5E This is a diagram showing the stationary blade segment as viewed from the radial inside in some other embodiments.

[0039] Figure 5 Figure 5F This is a diagram showing the stationary blade segment as viewed from the radial inside in some other embodiments.

[0040] Figure 5 Figure 5G This is a diagram showing the stationary blade segment as viewed from the radial inside in some other embodiments.

[0041] Figure 6 This is a diagram used to illustrate the weighted average position of the inhalation section.

[0042] Figure 7 This is a diagram used to illustrate the groove, which is inclined relative to the circumferential direction and will be described later. Detailed Implementation

[0043] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the constituent parts described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0044] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configuration not only indicate such configuration in a strict sense, but also indicate a state of relative displacement by angle or distance with tolerance or to the extent that the same function can be obtained.

[0045] For example, expressions such as "same," "equal," and "homogeneous" that indicate things are in the same state not only mean that they are the same in a strict sense, but also that there are differences in the degree to which they can achieve the same function.

[0046] For example, the descriptions of shapes such as quadrilaterals and cylinders not only refer to quadrilaterals and cylinders in a strict geometric sense, but also include shapes with concave and convex parts, chamfered parts, etc., within the range where the same effect can be obtained.

[0047] On the other hand, the expression "possessing," "having," "including," "containing," or "having" a constituent element is not an exclusive expression that excludes the existence of other constituent elements.

[0048] refer to Figure 1 The steam turbine 10 of this embodiment will be described below. For ease of explanation, in... Figure 1 and the following Figures 2 to 7 In this design, the extension direction of the axis O of the rotating shaft 11 of the steam turbine 10 is defined as the axial direction Da, the circumferential direction of the axis O of the rotating shaft 11 is defined as the circumferential direction Dc, and the radial direction of the rotating shaft 11 is defined as the radial direction Dr. Figure 1 In the diagram, arrow S indicates the direction of steam flow S.

[0049] The steam turbine 10 has: a rotor 14 having a rotating shaft 11 and multiple moving blade groups 13; a housing 16; multiple stationary blade segments 19; a journal bearing 23; and a thrust bearing 25.

[0050] The rotating shaft 11 extends along the axial direction Da. With both ends of the rotating shaft 11 positioned outside the housing 16, the portion of the rotating shaft 11 located between one end and the other end is housed within the housing 16.

[0051] The moving blade assembly 13 is fixed to the surface of the rotating shaft 11 and housed within the housing 16. The moving blade assembly 13 has a plurality of moving blades 28 spaced apart in the circumferential direction Dc of the rotating shaft 11. The moving blade assembly 13 also has a plurality of moving blades spaced apart in the axial direction Da.

[0052] The moving blade 28 has a blade body 31 and a moving blade shroud 33. The blade body 31 extends from the outer periphery of the rotation shaft 11 toward the radially outward side (radial Dr outward side).

[0053] The moving blade shroud 33 is disposed at the front end of the blade body 31. The contact surface of the moving blade shroud 33 abuts against the contact surface of another moving blade shroud 33 disposed at an adjacent position in the circumferential direction Dc.

[0054] In some embodiments of the steam turbine 10, a stator blade ring 20 is formed by arranging a plurality of stator blade segments 19 (described later) on the circumferential direction Dc. A plurality of stator blade rings 20 are arranged at intervals in the axial direction Da. The stator blade rings 20 are alternately arranged with the moving blade assembly 13 in the axial direction Da.

[0055] The housing 16 has a housing body 41, a steam supply pipe 42 and a steam discharge pipe 43.

[0056] The housing body 41 is a cylindrical component extending along the axial direction Da. The housing body 41 houses a plurality of moving blade assemblies 13 and a portion of a rotating shaft 11 on which the plurality of moving blade assemblies 13 are disposed.

[0057] Steam supply pipe 42 is located on one side of the housing body 41 in the axial direction Da. Steam supply pipe 42 functions as a steam inlet for introducing steam S into the housing body 41.

[0058] Steam discharge pipe 43 is located on the other side of the axial direction Da of the housing body 41. Steam discharge pipe 43 functions as a steam outlet for discharging steam S to the outside of the housing body 41.

[0059] Multiple stationary blade segments 19 are arranged along the inner circumferential surface 41a of the housing body 41. The multiple stationary blade segments 19 are spaced apart in the axial direction Da. In the axial direction Da, a moving blade group 13 is arranged between each adjacent stationary blade segment 19.

[0060] The static leaf segment 19 will be described in detail later.

[0061] A stationary blade guard 57 is disposed at the front end of each stationary blade 55, as described later. The contact surface of the stationary blade guard 57 abuts against the contact surface of another stationary blade guard 57 disposed at an adjacent position in the circumferential direction Dc.

[0062] Journal bearings 23 support both ends of the rotating shaft 11. Journal bearings 23 support the radial load Dr.

[0063] The thrust bearing 25 is disposed only on one side of the rotating shaft 11 in the axial direction Da. The thrust bearing 25 supports the rotating shaft 11 in the axial direction Da.

[0064] After steam S is supplied into the housing body 41 via steam supply pipe 42, it passes through the gap between multiple stationary blade segments 19 and multiple moving blade groups 13 as the rotating shaft 11 rotates, and is discharged to the outside of the housing 16 via steam discharge pipe 43.

[0065] (Regarding the static blade segment 19)

[0066] The following is for reference. Figures 1 to 7 The specific structure of the stationary blade segment 19 is explained.

[0067] Figure 2 This is a schematic cross-sectional view of the stationary blade segment and housing involved in some embodiments, viewed circumferentially, and is equivalent to the description below. Figure 5B The diagram shows the II-II view section.

[0068] Figure 3 This diagram, used to illustrate the secondary flow of steam, is a view of the stationary blade segment from the radial inward perspective. It represents the blade-like portion of multiple stationary blades in cross-section. Additionally, in Figure 3 The internal structure of the stationary blade 55 is omitted from the diagram. Furthermore, in... Figure 3 In the middle, arrow D represents Figure 1 The rotation direction of the rotating shaft 11 shown.

[0069] Figure 4 It will be discussed later. Figure 5A Sectional view in direction IV-IV.

[0070] Figure 5A This is a diagram showing a stationary blade segment according to one embodiment, viewed from the radial inward side; it is a cross-section representing the blade-like portion of multiple stationary blades. Additionally, in Figure 5A And as will be discussed later Figures 5B to 5G , Figure 7 The internal structure of the stationary blade 55 is omitted from the diagram.

[0071] Figures 5B to 5G This is a diagram showing the stationary blade segment of some other embodiments viewed from the radial inside, and a diagram showing the blade-like portion of multiple stationary blades in cross section.

[0072] Figure 6 This is a diagram used to illustrate the weighted average position of the inhalation section, which will be described later.

[0073] Figure 7 This is a diagram used to illustrate the groove, which is inclined relative to the circumferential direction and will be described later.

[0074] In addition, Figures 1 to 7 In this context, identical or corresponding components are marked with the same symbol.

[0075] Some embodiments involve a stationary blade segment 19 having a blade root ring 53, a plurality of stationary blades 55 and a plurality of stationary blade guards 57.

[0076] Some embodiments involve a stationary blade segment 19 having an intake section 70 for drawing condensate from the condensate tank 62 (described later) into the condensate chamber 59 (described later).

[0077] The blade root ring 53 is a ring-shaped component extending circumferentially along the Dc direction, also known as the outer wheel side guard. For example... Figure 2 As shown, the blade root ring 53 is fitted into the portion of the inner circumferential surface 41a of the housing body 41 that corresponds to the condensate drain flow path 41A formed in the housing body 41. One end of the condensate drain flow path 41A is exposed from the inner circumferential surface 41a of the housing body 41.

[0078] A fitting hole 53b is formed on the inner circumferential surface 53a of the blade root ring 53 for fitting a plurality of stationary blades 55 at intervals spaced apart in the circumferential direction Dc (see reference). Figure 4 In some embodiments, the stationary blade segment 19 has a fitting hole 53b extending from the inner circumferential surface 53a to the condensate chamber 59, which will be described later.

[0079] The blade root ring 53 has a blade root ring body 58, a condensate chamber 59, a connecting hole 61, and a condensate groove 62 as a condensate recess.

[0080] The condensate chamber 59 is an annular space formed inside the leaf root ring body 58.

[0081] The connecting hole 61 is located between one end of the condensate discharge flow path 41A and the condensate chamber 59, and is formed as the outer peripheral surface 53c of the radial Dr outside the condensate chamber 59 extending from the condensate chamber 59 to the blade root ring body 58.

[0082] Thus, the connecting hole 61 connects one end of the condensate drain flow path 41A to the condensate chamber 59.

[0083] The condensate drain 62 is formed as a groove between stationary blades 55 that are adjacent to each other in the circumferential direction Dc.

[0084] The condensate drain 62 is disposed on the leading edge 55A side of adjacent stationary blades 55 and extends circumferentially along the Dc direction. The condensate drain 62 is a groove recessed from the inner circumferential surface 53a of the blade root ring 53 toward the housing body 41, i.e. toward the radially outward Dr.

[0085] In some embodiments, the blade root ring 53 is able to collect condensate generated in wet steam in a condensate tank 62 having such a structure.

[0086] In addition, the cross-sectional shape of the condensate tank 62 when viewed along its extension direction is as follows: Figure 2 The shape shown is rectangular, but it could also be, for example, a shape with a width ( Figure 2 The groove in the wall is inclined in a way that narrows as it moves radially outward (Da) in the left-right direction, i.e., the axial direction.

[0087] Multiple stationary blades 55 are arranged at intervals on the inner circumferential surface 53a of the blade root ring 53 in a circumferentially spaced manner on the blade root ring Dc. The multiple stationary blades 55 extend from the inner circumferential surface 53a of the blade root ring 53 toward the radially inward side Dr.

[0088] The stationary blade 55 has a blade-like portion 55F. The blade-like portion 55F has a positive pressure surface 55a, a negative pressure surface 55b, a leading edge 55A, and a trailing edge 55B.

[0089] The negative pressure surface 55b is disposed on the side opposite to the positive pressure surface 55a. The leading edge 55A is disposed on the upstream side of the steam S in the flow direction and connects the positive pressure surface 55a and the negative pressure surface 55b.

[0090] The trailing edge 55B is positioned downstream of the steam S in the flow direction and connects the positive pressure surface 55a and the negative pressure surface 55b.

[0091] The blade height direction H of stationary blade 55 is the same as the radial direction Dr.

[0092] As described above, in some embodiments of the stationary blade segment 19, the radially outer end of the blade-shaped portion 55F is fitted into the fitting hole 53b of the blade root ring 53. With the radially outer end of the blade-shaped portion 55F fitted into the fitting hole 53b, it is joined to the blade root ring 53 via the connecting portion 80.

[0093] In some embodiments of the stationary blade segment 19, the joining portion 80 is, for example, a welded portion that joins the blade-shaped portion 55F and the blade root ring 53 by welding, namely the welded portion between the first blade-shaped portion 551F and the blade root ring 53 described later, and the welded portion between the second blade-shaped portion 552F and the blade root ring 53 described later. The joining portion 80 is provided between the outer surface of the blade-shaped portion 55F, such as the positive pressure surface 55a or the negative pressure surface 55b, and the inner peripheral surface 53a of the blade root ring 53.

[0094] Thus, the first blade-shaped portion 551F and the leaf root ring 53, and the second blade-shaped portion 552F and the leaf root ring 53, can be joined by welding.

[0095] exist Figure 5A , Figure 5B , Figure 5C , Figure 5D , Figure 5G and Figure 7 In the embodiment shown, the joint 80 does not cross the condensate drain 62, that is, it is provided in the entire circumference of the blade-shaped portion 55F except for the portion that intersects with the condensate drain 62. The portion where the joint 80 is not provided in order to avoid crossing the condensate drain 62 is referred to as the unprovided portion 81.

[0096] exist Figure 5E and Figure 5F In the embodiment shown, the joint portion 80 is provided along the entire circumference of the blade-shaped portion 55F.

[0097] As described above, in some embodiments of the stationary blade segment 19, the radially outer end of the blade-like portion 55F is fitted into the fitting hole 53b of the blade root ring 53. Therefore, a gap 71 exists between the outer surface of the blade-like portion 55F, such as the positive pressure surface 55a or the negative pressure surface 55b, and the inner circumferential surface 53a of the blade root ring 53 (see reference). Figure 4 However, the radially inner end of the gap 71 is blocked by the joint 80.

[0098] exist Figure 5A , Figure 5B , Figure 5C , Figure 5D , Figure 5G and Figure 7 In the embodiment shown, since the joint 80 does not cross the condensate drain 62, the gap 71 is not covered by the joint 80 at the location where the condensate drain 62 is located. Instead, the gap 71 is exposed when the inner circumferential surface 53a of the leaf root ring 53 is viewed from the radial inside Dr toward the outside.

[0099] (Regarding the secondary flow of steam)

[0100] refer to Figure 3 The secondary flow of steam S flowing between adjacent stationary blades 55 on the circumferential direction Dc will be described. In the two adjacent stationary blades 55 on the circumferential direction Dc, the positive pressure surface 55a of one stationary blade 55 faces the negative pressure surface 55b of the other stationary blade 55.

[0101] For ease of explanation, in the following description, one of the stationary blades 55 will be referred to as the first stationary blade 551, and the other stationary blade 55 will be referred to as the second stationary blade 552. Furthermore, in the following description, the blade-shaped portion 55F of the first stationary blade 551 will be referred to as the first blade-shaped portion 551F, the positive pressure surface 55a of the first stationary blade 551 will be referred to as the first positive pressure surface 551a, and the negative pressure surface 55b of the first stationary blade 551 will be referred to as the first negative pressure surface 551b. Similarly, in the following description, the blade-shaped portion 55F of the second stationary blade 552 will be referred to as the second blade-shaped portion 552F, the positive pressure surface 55a of the second stationary blade 552 will be referred to as the second positive pressure surface 552a, and the negative pressure surface 55b of the second stationary blade 552 will be referred to as the second negative pressure surface 552b.

[0102] When steam S flows in the flow path 94 between the first stationary blade 551 and the second stationary blade 552, near the inner circumferential surface 53a of the blade root ring 53, as shown by arrow 95, the secondary flow of steam S flows from near the leading edge 55A of the first blade-shaped portion 551F toward the second negative pressure surface 552b of the second stationary blade 552 in a manner that crosses the main flow of steam S (not shown).

[0103] Therefore, the condensate attached to the inner circumferential surface 53a of the blade root ring 53 is affected by the secondary flow of the steam S mentioned above, and flows from the first positive pressure surface 551a of the first blade-shaped portion 551F toward the second negative pressure surface 552b of the second stationary blade 552.

[0104] The inventors, through in-depth research, determined that the condensate attached to the inner circumferential surface 53a of the blade root ring 53, due to the influence of the secondary flow of the steam S mentioned above, tends to flow on the inner circumferential surface 53a of the blade root ring 53 along the edge of the leading edge 55A side of the condensate tank 62 from the first positive pressure surface 551a of the first blade-shaped portion 551F toward the second negative pressure surface 552b of the second stationary blade 552.

[0105] Therefore, it is determined that when a suction part 70 is provided as a hole, slit, gap, or the like for drawing condensate from the condensate tank 62 into the condensate chamber 59, it is preferable to provide it as close as possible to the second negative pressure surface 552b of the second stationary blade 552.

[0106] Furthermore, in the following description, when describing two adjacent stationary blades 55 on the circumferential Dc, as described above, one stationary blade 55 is designated as the first stationary blade 551, and the other stationary blade 55 is designated as the second stationary blade 552.

[0107] Therefore, in some embodiments of the stationary blade segment 19, for example, as Figure 5A , Figure 5B , Figure 5C , Figure 5D , Figure 5G and Figure 7 As shown, the gap 71 exposed when viewing the inner circumferential surface 53a of the leaf root ring 53 from the radial inside to the outside and in contact with the condensate tank 62 is used as an intake part 70 for drawing condensate from the condensate tank 62 into the condensate chamber 59.

[0108] Furthermore, in some embodiments of the stationary blade segment 19, for example, as Figure 5B , Figure 5C , Figure 5D , Figure 5E , Figure 5F , Figure 5G and Figure 7 As shown, the hole 72 or slit 73, which serves as the suction part 70, can be provided together with or in place of the gap 71 in the condensate tank 62.

[0109] exist Figure 5B , Figure 5G and Figure 7 In the embodiment shown, the hole 72 and the aforementioned gap 71 are together placed in the condensate tank 62.

[0110] exist Figure 5E and Figure 5F In the embodiment shown, a hole 72 is provided in the condensate tank 62 to replace the gap 71 mentioned above.

[0111] Hole 72 is located at the bottom surface 62a of the condensate drain 62 (reference). Figure 2 , Figure 4 The hole 72 extends radially outward from Dr and reaches the condensate chamber 59. The hole 72 connects the condensate drain 62 to the condensate chamber 59.

[0112] Hole 72 is used to guide the condensate that is directed to the condensate tank 62 to the condensate chamber 59.

[0113] The diameter of the hole 72 is configured to be smaller than the width of the condensate drain 62, but it can also be the same as the width of the condensate drain 62.

[0114] When holes 72 are provided in the condensate tank 62, the number of holes 72 provided in the flow path 94 between each blade can be one or more.

[0115] As described above, the hole 72 in the condensate drain 62 is preferably positioned on the circumferential Dc near the second negative pressure surface 552b of the second stationary blade 552.

[0116] exist Figure 5C and Figure 5DIn the illustrated embodiment, the slit 73 and the aforementioned gap 71 are both disposed within the condensate drain 62. Furthermore, in Figure 5C In the embodiment shown, the slit 73 is positioned at a location separate from the gap 71 in the circumferential direction Dc. Figure 5D In the embodiment shown, the end of the slit 73 on the circumferential Dc is connected to the gap 71.

[0117] Alternatively, although not shown in the figure, a slit 73 can be provided in the condensate drain 62 to replace the gap 71 mentioned above.

[0118] Slit 73 extends from the bottom surface 62a of condensate drain 62 (reference) Figure 2 , Figure 4 It extends radially outward from Dr and reaches the condensate chamber 59. The slit 73 connects the condensate drain 62 to the condensate chamber 59.

[0119] Slit 73 is a slit used to guide condensate that will be directed into the condensate tank 62 to the condensate chamber 59.

[0120] The slit 73 is configured to be smaller than the width W1 of the condensate tank 62 in the width direction, but it can also be the same as the width of the condensate tank 62.

[0121] The dimension of the slit 73 in the extending direction of the condensate tank 62 is not particularly limited, but if it is too large, it will cause steam S to be undesirably guided to the condensate chamber 59. Therefore, it is preferable to set it appropriately from the viewpoint of increasing the amount of condensate recovered and reducing the amount of steam S drawn in. In addition, the dimension of the slit 73 in the extending direction of the condensate tank 62 can be less than or equal to the dimension of the slit 73 in the width direction of the condensate tank 62.

[0122] When a slit 73 is provided in the condensate tank 62, the number of slits 73 provided in the flow path 94 between each blade can be one or more.

[0123] As described above, the circumferential position of the slit 73 in the condensate drain 62 on the slit Dc is preferably located near the second negative pressure surface 552b of the second stationary blade 552.

[0124] Thus, in some embodiments of the stationary blade segment 19, at least one suction part 70 is preferably any one of a hole 72, a slit 73 or a gap 71 that is connected to the condensate tank 62 within the condensate tank 62.

[0125] Therefore, condensate can be recovered with a relatively simple structure.

[0126] In some embodiments, at least one suction section 70 preferably includes the aforementioned gap 71 in the stationary blade segment 19. The gap 71 is preferably formed between the blade root ring 53 and the second negative pressure surface 552b of the second blade-shaped portion 552F.

[0127] Therefore, the gap 71 between the outer surface (blade surface) of the base end of the blade-shaped portion 55F and the fitting hole 53b formed in the leaf root ring 53 can be used as a gap 71 for condensate recovery, so there is no need to form a separate gap 71 for condensate recovery, thereby reducing costs.

[0128] In some embodiments, the stationary blade segment 19 preferably includes a joint 80 disposed between the first blade-shaped portion 551F and the blade root ring 53, and between the second blade-shaped portion 552F and the blade root ring 53. Preferably, the joint 80 is not disposed between the condensate drain 62 and the second negative pressure surface 552b of the second blade-shaped portion 552F.

[0129] Therefore, the gap 71 between the outer surface (blade surface) of the base end of the blade-shaped portion 55F and the fitting hole 53b formed in the blade root ring 53 will not be blocked by the joint 80 between the condensate tank 62 and the second negative pressure surface 552b of the second blade-shaped portion 552F. Thus, the gap 71 between the outer surface (blade surface) of the base end of the blade-shaped portion 55F and the fitting hole 53b formed in the blade root ring 53 can be used as a gap for condensate recovery.

[0130] (Weighted average position of the inhalation section 70)

[0131] As described above, the suction section 70, including the gap 71, the hole 72, and the slit 73, is preferably located near the second negative pressure surface 552b of the second stationary blade 552. Hereinafter, reference will be made to... Figure 6 The position of the intake portion 70 in the stationary blade segment 19 according to some embodiments will be described.

[0132] The first intersection position 91 is defined as the position where the condensate drain 62 intersects with the first positive pressure surface 551a when viewed from the blade height direction H of the first blade-shaped portion 551F, or the position where the extension line L of the condensate drain 62 extending towards the first positive pressure surface 551a intersects with the first positive pressure surface 551a. The second intersection position 92 is defined as the position where the condensate drain 62 intersects with the second negative pressure surface 552b when viewed from the blade height direction H of the second blade-shaped portion 552F, or the position where the extension line L of the condensate drain 62 extending towards the second negative pressure surface 552b intersects with the second negative pressure surface 552b.

[0133] In some embodiments, the weighted average position xA of the intake section 70 is preferably closer to the second cross position 92 than the first cross position 91.

[0134] Here, the weighted average position xA of the suction section 70 refers to the value obtained by weighting the center position x of the suction section 70 on the circumferential direction Dc with the opening area s of the suction section 70, which will be described in detail below.

[0135] For example, such as Figure 5B and Figure 6 As shown, the case where the suction section 70 includes one gap 71 and two holes 72 will be described.

[0136] Set the circumferential Dc position of the first intersection position 91 to 0, and set the circumferential Dc position of the second intersection position 92 to 1.

[0137] Within the two holes 72, the circumferential Dc position of the center (centroid) of the hole 72 closest to the first intersection position 91 is set as x1, and the opening area is set as s1. Within the two holes 72, the circumferential Dc position of the center (centroid) of the hole 72 furthest from the first intersection position 91 is set as x2, and the opening area is set as s2.

[0138] Set the circumferential Dc position of the center (centroid) of gap 71 to x3, and set the opening area to s3.

[0139] exist Figure 6 In the example, the weighted average position xA of the inhalation section 70 is as follows.

[0140] xA=(x1×s1+x2×s2+x3×s3) / (s1+s2+s3)

[0141] That is, the circumferential Dc positions of the centers (centroids) of the n suction sections 70 are set as x1, x2, ..., xn, and their respective opening areas are set as s1, s2, ..., sn. The weighted average position xA of the suction sections 70 at this time is as follows.

[0142] xA=(x1×s1+x2×s2+……+xn×sn) / (s1+s2+……+sn)

[0143] As described above, in the stationary blade segment 19 of some embodiments, the weighted average position xA of the intake section 70 is preferably closer to the second cross position 92 than the first cross position 91. That is, when the circumferential Dc position of the first cross position 91 is set to 0 and the circumferential Dc position of the second cross position 92 is set to 1, the weighted average position xA of the intake section 70 is preferably 0.5 or more.

[0144] Therefore, as described above, the condensate recovery efficiency can be improved by increasing the tendency of the condensate to flow from the first positive pressure surface 551a of the first blade-shaped portion 551F toward the second negative pressure surface 552b of the second stationary blade 552 along the edge of the leading edge 55A side of the condensate groove 62 on the inner peripheral surface 53a of the blade root ring 53.

[0145] Furthermore, in some embodiments, the stationary blade ring 20 is provided with a plurality of stationary blade segments 19 as described above on the circumferential Dc.

[0146] Therefore, a stationary blade ring 20 that can improve the efficiency of condensate recovery can be provided.

[0147] The steam turbine 10 according to the embodiment includes the aforementioned stator ring 20.

[0148] This improves the condensate recovery efficiency in the steam turbine 10.

[0149] Furthermore, the weighted average position xA of the inhalation section 70 is preferably 0.7 or higher, for example.

[0150] (Regarding the extension direction of condensate drain 62)

[0151] exist Figures 5A to 5G In the illustrated embodiment, the extension direction of the condensate drain 62 is consistent with the circumferential direction Dc. That is, in Figures 5A to 5G In the embodiment shown, the angle difference between the extension direction of the condensate drain 62 and the circumferential direction Dc is 0 degrees.

[0152] In order to recover the condensate adhering to the inner circumferential surface 53a of the leaf root ring 53, it is preferable to increase the amount of condensate reaching the edge of the leading edge 55A side of the condensate trough 62.

[0153] However, when the extension direction of the condensate drain 62 differs significantly from the circumferential direction Dc, the condensate adhering to the inner circumferential surface 53a of the blade root ring 53 is more likely to flow downstream instead of reaching the edge of the leading edge 55A side of the condensate drain 62.

[0154] However, as Figure 7 As shown, in some embodiments of the stationary blade segment 19, the extension direction of the condensate drain 62 may be different from the circumferential direction Dc.

[0155] At this time, in some embodiments of the stationary blade segment 19, the absolute value of the angle difference Δθ between the extension direction of the condensate drain 62 and the circumferential direction Dc is preferably 20 degrees or less.

[0156] Therefore, the extension direction of the condensate tank 62 is relatively along the circumferential direction Dc, which increases the amount of condensate reaching the edge of the leading edge 55A side of the condensate tank 62, thereby improving the condensate recovery efficiency.

[0157] Furthermore, in some embodiments of the stationary blade segment 19, the absolute value of the angle difference Δθ between the extension direction of the condensate drain 62 and the circumferential direction Dc is preferably 10 degrees or less.

[0158] Therefore, the extension direction of the condensate tank 62 is further along the circumferential direction Dc, which can further increase the amount of condensate reaching the edge of the leading edge 55A side of the condensate tank 62, thereby further improving the condensate recovery efficiency.

[0159] Furthermore, in some embodiments of the stationary blade segment 19, the extension direction of the condensate drain 62 is preferably aligned with the circumferential direction Dc.

[0160] This allows for a further increase in the amount of condensate reaching the leading edge 55A of the condensate drain 62, thereby further improving condensate recovery efficiency. Furthermore, if the extending direction of the condensate drain 62 is aligned with the circumferential direction Dc, multiple condensate drains 62 facing each of the multiple inter-blade flow paths 94 arranged on the circumferential direction Dc can be arranged in a row on the circumferential direction Dc. Therefore, when machining the condensate drain 62, for example, by cutting, by moving the tool and the blade root ring 53 relative to each other on the circumferential direction Dc, machining of multiple condensate drains 62 can be performed simultaneously. This significantly reduces the machining cost of the condensate drain 62.

[0161] The present invention is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments or appropriate combinations thereof.

[0162] Additionally, one end of the condensate drain tank 62 in the extending direction can be as follows: Figures 5A to 5F The joint 80 that reaches the first leaf-shaped portion 551F shown can also be as follows: Figure 5G It is separated from the condensate drain 62 as shown. The other end of the condensate drain 62, in its extending direction, can be as follows: Figures 5A to 5D and Figure 5G The fitting hole 53b shown above allows the second blade-shaped portion 552F to fit into the fitting hole, or it can be as follows: Figure 5E The joint 80 shown does not reach the fitting hole 53b but reaches the second blade-shaped portion 552F, and can also be as follows: Figure 5F It is shown to be separated from the joint 80.

[0163] The contents described in the above embodiments are as follows.

[0164] (1) The stationary blade segment 19 according to at least one embodiment of the present invention includes: a first stationary blade 551; a second stationary blade 552 adjacent to the first stationary blade 551; and an outer wheel side guard (blade root ring 53) for mounting the first blade-shaped portion 551F of the first stationary blade 551 and the second blade-shaped portion 552F of the second stationary blade 552. The first ventral surface (first positive pressure surface 551a) of the first blade-shaped portion 551F faces the second back surface (second negative pressure surface 552b) of the second blade-shaped portion 552F. The stationary blade segment 19 according to at least one embodiment of the present invention includes: a groove (condensate groove 62) disposed on the inner peripheral surface 53a of the outer wheel side guard (blade root ring 53), located between the first ventral surface (first positive pressure surface 551a) and the second back surface (second negative pressure surface 552b), extending from the first ventral surface (first positive pressure surface 551a) toward the second back surface (second negative pressure surface 552b); and at least one suction part 70 disposed in the groove (condensate groove 62) or disposed in connection with the groove (condensate groove 62) and communicating with the internal space (condensate chamber 59) of the outer wheel side guard (blade root ring 53). The first intersection position 91 is defined as the intersection of the groove (condensate drain 62) and the first ventral surface (first positive pressure surface 551a) when viewed from the blade height direction H of the first blade-shaped portion 551F, or the intersection of the extension line L of the groove (condensate drain 62) extending towards the first ventral surface (first positive pressure surface 551a) with the first ventral surface (first positive pressure surface 551a). The second intersection position 92 is defined as the intersection of the groove (condensate drain 62) and the second back surface (second negative pressure surface 552b) when viewed from the blade height direction H of the second blade-shaped portion 552F, or the intersection of the extension line L of the groove (condensate drain 62) extending towards the second back surface (second negative pressure surface 552b) with the second back surface (second negative pressure surface 552b). The center position x of each suction section 70 in the direction from the first intersection position 91 toward the second intersection position 92, and the weighted average position xA of at least one suction section 70 weighted by the opening area s of the suction section 70, is closer to the second intersection position 92 than the first intersection position 91.

[0165] According to the configuration described in (1) above, the weighted average position xA of at least one suction section 70 is closer to the second cross position 92 than the first cross position 91. Therefore, it is possible to improve the recovery efficiency of condensate water that tends to flow as described above.

[0166] (2) In some embodiments, in the configuration described in (1) above, the absolute value of the angle difference Δθ between the extension direction of the groove (condensate groove 62) and the circumferential direction (circumferential Dc) of the outer wheel side guard (blade root ring 53) is preferably 20 degrees or less.

[0167] According to the above (2) configuration, the extension direction of the trough (condensate trough 62) is relatively along the circumference (circumferential Dc) of the outer wheel side guard (blade root ring 53), so the amount of condensate reaching the edge of the leading edge 55A side of the trough (condensate trough 62) can be increased, thereby improving the condensate recovery efficiency.

[0168] (3) In some embodiments, in the configuration described in (1) above, the absolute value of the angle difference Δθ between the extension direction of the groove (condensate groove 62) and the circumferential direction (circumferential Dc) of the outer wheel side guard (blade root ring 53) is preferably 10 degrees or less.

[0169] According to the above (3) configuration, the extension direction of the tank (condensate tank 62) is further along the circumference (circumferential Dc) of the outer wheel side cover (blade root ring 53), so the amount of condensate reaching the edge of the leading edge 55A side of the tank (condensate tank 62) can be further increased, thereby further improving the condensate recovery efficiency.

[0170] (4) In some embodiments, in the configuration described in (1) above, it is preferable that the extension direction of the groove (condensate groove 62) is consistent with the circumferential direction (circumferential Dc) of the outer wheel side guard (blade root ring 53).

[0171] According to the configuration described in (4) above, the amount of condensate reaching the edge 55A of the groove (condensate groove 62) can be further increased, thereby further improving the condensate recovery efficiency. Furthermore, according to the configuration described in (4) above, multiple grooves (condensate grooves 62) facing each of multiple inter-blade flow paths 94 arranged on the circumferential Dc can be arranged in a row on the circumferential Dc. Therefore, when machining the groove (condensate groove 62), for example by cutting, by moving the tool and the outer wheel side guard (blade root ring 53) relative to each other on the circumferential Dc, machining of multiple grooves (condensate grooves 62) can be performed simultaneously. This significantly reduces the machining cost of the groove (condensate groove 62).

[0172] (5) In some embodiments, in any of the configurations in (1) to (4) above, at least one suction part 70 is preferably any one of a hole 72, a slit 73 or a gap 71 provided in the groove (condensate groove 62) to connect with the groove (condensate groove 62).

[0173] Based on the above (5) structure, condensate can be recovered with a relatively simple structure.

[0174] (6) In some embodiments, in the configuration described in (5) above, at least one suction section 70 preferably includes the aforementioned gap 71. The aforementioned gap 71 is preferably formed between the outer wheel side guard (blade root ring 53) and the second back surface (second negative pressure surface 552b) of the second blade-shaped portion 552F.

[0175] According to the above (6) configuration, the gap 71 between the outer surface (positive pressure surface 55a, negative pressure surface 55b) of the base end of the blade-shaped portion 55F and the hole (fitting hole 53b) formed in the outer wheel side cover (blade root ring 53) can be used as a gap 71 for condensate recovery, so there is no need to form a gap 71 for condensate recovery separately, thereby reducing costs.

[0176] (7) In some embodiments, in any of the configurations described in (1) to (6) above, it is preferable to have a joint portion 80 provided between the first blade-shaped portion 551F and the outer wheel side guard (blade root ring 53) and between the second blade-shaped portion 552F and the outer wheel side guard (blade root ring 53). It is preferable not to provide a joint portion 80 between the groove portion (condensate groove 62) and the second back surface (second negative pressure surface 552b) of the second blade-shaped portion 552F.

[0177] According to the above configuration (7), the gap 71 between the outer surface (positive pressure surface 55a, negative pressure surface 55b) of the base end of the blade-shaped portion 55F and the hole (fitting hole 53b) formed in the outer wheel side cover (blade root ring 53) will not be blocked by the joint portion 80 between the groove portion (condensate groove 62) and the second back surface (second negative pressure surface 552b) of the second blade-shaped portion 552F. Therefore, the gap 71 between the outer surface (positive pressure surface 55a, negative pressure surface 55b) of the base end of the blade-shaped portion 55F and the hole (fitting hole 53b) formed in the outer wheel side cover (blade root ring 53) can be used as a gap for condensate recovery.

[0178] (8) In some embodiments, in the configuration of (7) above, the joint 80 is preferably the welded part of the first blade-shaped part 551F and the outer wheel side guard (blade root ring 53) and the welded part of the second blade-shaped part 552F and the outer wheel side guard (blade root ring 53).

[0179] According to the above (8) configuration, the first blade-shaped portion 551F and the outer wheel side guard (blade root ring 53) and the second blade-shaped portion 552F and the outer wheel side guard (blade root ring 53) can be joined by welding.

[0180] (9) In the stationary blade ring 20 according to at least one embodiment of the present invention, a plurality of stationary blade segments 19 configured as described in any of (1) to (8) are arranged on the circumferential direction (circumferential Dc) of the outer wheel side guard (blade root ring 53).

[0181] Based on the above (9) configuration, a stationary blade ring 20 that can improve the efficiency of condensate recovery can be provided.

[0182] (10) The steam turbine 10 according to at least one embodiment of the present invention has a stator ring 20 with the configuration described in (7) above.

[0183] Based on the above (10) configuration, the condensate recovery efficiency in the steam turbine 10 can be improved.

[0184] Symbol Explanation

[0185] 10-Steam turbine, 11-Rotating shaft, 19-Stationary blade segment, 20-Stationary blade ring, 53-Blade root ring, 53a-Inner circumferential surface, 53b-Matching hole, 55-Stationary blade, 55A-Leading edge, 55a-Positive pressure surface, 55B-Leading edge, 55b-Negative pressure surface, 55F-Blade-shaped part, 59-Condensate chamber, 62-Condensate tank, 70-Suction section, 71-Gap, 72-Hole, 7 3-Slit, 80-Joint, 81-Unset part, 91-First intersection position, 92-Second intersection position, 94-Flow path between blades, 551-First stationary blade, 551a-First positive pressure surface, 551b-First negative pressure surface, 551F-First blade-shaped part, 552-Second stationary blade, 552a-Second positive pressure surface, 552b-Second negative pressure surface, 552F-Second blade-shaped part.

Claims

1. A static leaf segment, comprising: First stationary blade; The second stationary blade is adjacent to the first stationary blade; and The outer wheel side guard is for mounting the first blade-shaped portion of the first stationary blade and the second blade-shaped portion of the second stationary blade. The first ventral surface of the first leaf-shaped portion faces the second back surface of the second leaf-shaped portion. The stationary blade segment also features: A groove, disposed on the inner circumferential surface of the outer wheel side guard, located between the first ventral surface and the second rear surface, extending from the first ventral surface toward the second rear surface; and At least one suction unit is disposed within the groove or configured to connect with the groove and communicate with the internal space of the outer wheel side guard. The first intersection position is defined as the position where the groove intersects with the first ventral surface when viewed from the blade height direction of the first blade-shaped portion, or the position where the extension line of the groove extending towards the first ventral surface intersects with the first ventral surface. The second intersection point is defined as the position where the groove intersects the second back surface when viewed from the blade height direction of the second blade-shaped portion, or the position where the extension line of the groove extending towards the second back surface intersects the second back surface. The weighted average position of at least one inhalation part, which is the weighted average position of the center positions of each of the inhalation parts in the direction from the first intersection position toward the second intersection position using the opening area of ​​the inhalation part, is closer to the second intersection position than the first intersection position.

2. The stationary blade segment according to claim 1, wherein, The absolute value of the angle difference between the extension direction of the groove and the circumferential direction of the outer wheel side guard is less than 20 degrees.

3. The stationary blade segment according to claim 1, wherein, The absolute value of the angle difference between the extension direction of the groove and the circumferential direction of the outer wheel side guard is less than 10 degrees.

4. The stationary blade segment according to claim 1, wherein, The extension direction of the groove is consistent with the circumferential direction of the outer wheel side guard.

5. The stationary blade segment according to any one of claims 1 to 4, wherein, The at least one suction part is any one of a hole, a slit, or a gap disposed within the groove and connected to the groove.

6. The stationary blade segment according to claim 5, wherein, The at least one inhalation portion includes the gap. The gap is formed between the outer wheel side guard and the second back surface of the second blade-shaped portion.

7. The stationary blade segment according to any one of claims 1 to 4, comprising: The connecting portion is disposed between the first blade-shaped portion and the outer wheel side guard, and between the second blade-shaped portion and the outer wheel side guard. The connecting portion is not provided between the groove and the second back surface of the second blade-shaped portion.

8. The stationary blade segment according to claim 7, wherein, The joint is the welded part between the first blade-shaped part and the outer wheel side guard, and the welded part between the second blade-shaped part and the outer wheel side guard.

9. A static leaf ring, wherein, The outer wheel side guard is provided with a plurality of stationary blade segments as described in any one of claims 1 to 4 in the circumferential direction.

10. A steam turbine comprising the stator ring as described in claim 9.

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