turbomachine

Abstract

A turbine includes a rotor having a rotor body rotatable about an axis and a plurality of rotor blades arranged in a circumferential direction along an outer peripheral surface of the rotor body; a casing covering the rotor; and a plurality of stator blades arranged in the circumferential direction along an inner peripheral surface of the casing, the stator blade having a stator blade body having an intake portion formed on a surface and extending in a radial direction and capable of sucking at least a portion of a working fluid, a nozzle inner peripheral member provided on a radially inner side of the stator blade body, and a plurality of seal fins protruding from an inner peripheral surface of the nozzle inner peripheral member toward the radially inner side, a portion of the nozzle inner peripheral member and the seal fins on a side further from the most one side in the axial direction than the seal fin on the other side being formed with a discharge port discharging the working fluid introduced from the intake portion.

Description

TECHNICAL FIELD

[0001] The present application relates to a turbine.

[0002] This application claims priority from Japanese Patent Application No. 2020-195481 filed on November 25, 2020, and the contents thereof are incorporated herein by reference. BACKGROUND

[0003] A gas turbine or a steam turbine mainly has a rotor that rotates around an axis, a casing that covers the rotor from an outer periphery side, and a plurality of stationary blade layers that are provided at an inner periphery side of the casing (see Patent Literature 1 described below). The rotor has a rotor main body that extends along the axis, and a plurality of rotating blade layers that are arranged on an outer peripheral surface of the rotor main body. The stationary blade layers and the rotating blade layers are alternately arranged in the axis direction. The stationary blade layers have a plurality of stationary blades that are arranged in the circumferential direction. Similarly, the rotating blade layers have a plurality of rotating blades that are arranged in the circumferential direction. Fluid introduced from the outside changes the flow direction by the stationary blade layers, and then flows into the rotating blade layers. Thereby, by the rotating blade layers, the energy of the steam is converted into rotational force, and thus the rotor rotates.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2018-138764 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In addition, it is known that when steam passes around the stationary blades, a flow layer called a boundary layer having a small flow velocity is formed in association with the viscosity possessed by the steam. If this boundary layer develops, energy loss occurs. As a result, the efficiency of the steam turbine can decrease. Furthermore, there is a request to reduce the steam flow (leakage flow) that flows between the stationary blade seal fin and the rotor to improve the efficiency of the turbine.

[0009] The present application has been achieved in order to solve the above problems, and aims to provide a steam turbine whose efficiency is further improved.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] To solve the above problems, a steam turbine according to the present application includes: a rotor having a rotor main body rotatable about an axis and a plurality of rotating blades arranged in a circumferential direction along an outer peripheral surface of the rotor main body; a casing covering the rotor; and a plurality of stationary blades arranged in the circumferential direction along an inner peripheral surface of the casing, the stationary blades having: a stationary blade main body having a suction portion formed on a surface, the suction portion extending in a radial direction with respect to the axis and being able to suction at least a part of a working fluid flowing from one side to the other side in the axis direction; a nozzle inner peripheral member provided on a radially inner side of the stationary blade main body; and a plurality of seal fins protruding from an inner peripheral surface of the nozzle inner peripheral member toward the radially inner side and arranged at intervals in the axis direction, a portion of the seal fins on the other side than the seal fins on the most one side in the axis direction being formed with a discharge port discharging the working fluid introduced from the suction portion.

[0012] Effects of the Invention

[0013] According to the present application, a steam turbine with further improved efficiency can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 FIG. 1 is a schematic view showing the structure of a steam turbine according to a first embodiment of the present application.

[0015] Figure 2 FIG. 2 is an enlarged sectional view of a main part of the steam turbine according to the first embodiment of the present application.

[0016] Figure 3 FIG. 3 is a perspective view of a stationary blade according to the first embodiment of the present application.

[0017] Figure 4 FIG. 4 is an enlarged sectional view of a seal fin according to the first embodiment of the present application.

[0018] Figure 5 FIG. 5 is a perspective view of a first modification example of the stationary blade according to the first embodiment of the present application.

[0019] Figure 6 FIG. 6 is a perspective view of a second modification example of the stationary blade according to the first embodiment of the present application.

[0020] Figure 7 FIG. 7 is a perspective view of a third modification example of the stationary blade according to the first embodiment of the present application.

[0021] Figure 8 FIG. 8 is an enlarged sectional view of a main part of a steam turbine according to a second embodiment of the present application.

[0022] Figure 9This is an enlarged cross-sectional view of the main part of the steam turbine according to the third embodiment of the present invention.

[0023] Figure 10 This is an enlarged cross-sectional view of the main part of a first modified example of a steam turbine according to the third embodiment of the present invention.

[0024] Figure 11 This is an enlarged cross-sectional view of the main part of a second modified example of a steam turbine according to the third embodiment of the present invention.

[0025] Figure 12 This is an enlarged cross-sectional view of the main part of a third modified example of a steam turbine according to the third embodiment of the present invention. Detailed Implementation

[0026] [First Implementation Method]

[0027] (Structure of a steam turbine)

[0028] The following is for reference. Figures 1 to 4 The steam turbine 1 (turbine) according to the first embodiment of the present invention will be described below. Figure 1 As shown, the steam turbine 1 includes a rotor 2, a housing 3, a fixed blade layer 9, a journal bearing 4, and a thrust bearing 5.

[0029] The rotor 2 has a rotor body 6 extending along axis Ac, and a plurality of rotating blade layers 7 arranged at intervals along axis Ac on the outer circumferential surface of the rotor body 6. A journal bearing 4 is provided at each of the two ends of the rotor body 6 along axis Ac. The journal bearing 4 supports radial loads based on the rotor body 6 and enables the rotor body 6 to rotate about axis Ac. A thrust bearing 5 is provided on one side of the rotor body 6 along axis Ac. The thrust bearing 5 supports loads based on the rotor body 6 in the direction of axis Ac.

[0030] Each rotating blade layer 7 has multiple rotating blades 8 arranged circumferentially along the outer peripheral surface of the rotor body 6. When viewed radially, each rotating blade 8 has a blade-shaped cross-section with one side of the axis Ac as the leading edge and the other side as the trailing edge.

[0031] The casing 3 is a cylindrical shape that covers the rotor 2 from the outside. A plurality of stationary blade layers 9 are arranged at intervals in the axial direction Ac on the inner peripheral surface of the casing 3. These stationary blade layers 9 are arranged alternately with the rotating blade layers 7 in the axial direction Ac. More specifically, one stationary blade layer 9 is provided on each side of the axial direction Ac of each rotating blade layer 7. Each stationary blade layer 9 has a plurality of stationary blades 10 arranged in the circumferential direction along the inner peripheral surface of the casing 3. When viewed in the radial direction, the stationary blades 10 have a blade-like cross-sectional shape in which the side in the axial direction Ac is set as the leading edge and the other side is set as the trailing edge.

[0032] A steam supply port 40 for guiding steam generated outside is provided on the side in the axial direction Ac of the casing 3. The steam introduced into the casing 3 through the steam supply port 40 changes the flow direction by the stationary blade layers 9 described above and collides with the rotating blade layers 7. Thus, the rotating energy around the axial direction Ac is imparted to the rotor 2 via the rotating blade layers 7. In addition, a steam discharge port 50 for discharging steam that has passed through the inside of the casing 3 is provided on the other side in the axial direction Ac of the casing 3. In the following description, the side (i.e., the side in the axial direction Ac) on which the steam supply port 40 is located when viewed from the steam discharge port 50 is sometimes simply referred to as the "upstream side", and the opposite side is simply referred to as the "downstream side".

[0033] (Structure of stationary blade)

[0034] Next, the detailed structure of the stationary blade 10 will be described with reference to Figure 2 and Figure 3 . As shown in Figure 2 , the stationary blade 10 has a nozzle outer peripheral member 31, a stationary blade main body 11, a nozzle inner peripheral member 12, and a stationary blade seal fin 13 (seal fin).

[0035] The nozzle outer peripheral member 31 is attached to the inner peripheral surface 3S of the casing 3. The nozzle outer peripheral member 31 is annular with the axial direction Ac as the center. The stationary blade main body 11 extends toward the radially inner side from the nozzle outer peripheral member 31. That is, the nozzle outer peripheral member 31 supports a plurality of stationary blade main bodies 11 arranged in the circumferential direction from the radially outer side.

[0036] As shown in Figure 3As shown, the end edge of the upstream side of the fixed blade body 11 is provided as a leading edge 11L, and the end edge of the downstream side is provided as a trailing edge 11T. A curved line (i.e., a line passing through the center of the blade-like cross section) connecting the leading edge 11L and the trailing edge 11T is provided as an arc line CL. With this arc line CL as a boundary, a surface toward one side in the circumferential direction is provided as a positive pressure surface 11A, and a surface toward the other side is provided as a negative pressure surface 11B. The positive pressure surface 11A is curvedly recessed toward the other side in the circumferential direction. The positive pressure surface 11A is toward the upstream side in the flow direction of the steam. The negative pressure surface 11B is curvedly protruded toward one side in the circumferential direction. The negative pressure surface 11B is toward the downstream side in the flow direction of the steam.

[0037] The negative pressure surface 11B is formed with a suction portion 20 that can suction at least a portion of the steam (working fluid) flowing around the fixed blade body 11. The suction portion 20 has a pair of leading edge side suction ports 21 formed at positions biased toward the leading edge 11L side, and one trailing edge side suction port 22 formed at a position biased toward the trailing edge 11T side.

[0038] The leading edge side suction ports 21 are rectangular openings with the radial direction as the length direction. Alternatively, the leading edge side suction ports 21 can be circular or elliptical. The pair of leading edge side suction ports 21 are separated from each other in the radial direction. One of the leading edge side suction ports 21 is formed near the radially outer end portion in the negative pressure surface 11B, and the other leading edge side suction port 21 is formed near the radially inner end portion. Further, the distance from the radially end portion of the fixed blade body 11 to the leading edge side suction ports 21 is smaller than the distance between the pair of leading edge side suction ports 21. Further, the positions in the axial Ac direction of the pair of leading edge side suction ports 21 are the same as each other. The "same" herein means substantially the same position, and allows for design tolerances or manufacturing errors. The same applies to the following description. Alternatively, a structure in which the positions in the axial Ac direction of the pair of leading edge side suction ports 21 are different from each other can be adopted.

[0039] The trailing edge side suction port 22 is a rectangular opening with the radial direction as the length direction. The trailing edge side suction port 22, unlike the above-described leading edge side suction ports 21, extends over almost the entire area in the radial direction in the negative pressure surface 11B. That is, the size in the radial direction of the trailing edge side suction port 22 is larger than that of the leading edge side suction ports 21. The radial position of the radially outer end portion of the trailing edge side suction port 22 is the same as that of the radially outer end portion of one (radially outer) leading edge side suction port 21. Further, the radial position of the radially inner end portion of the trailing edge side suction port 22 is the same as that of the radially inner end portion of the other (radially inner) leading edge side suction port 21.

[0040] The interior of the fixed blade body 11 is hollow, and the aforementioned suction section 20 (leading edge suction port 21 and trailing edge suction port 22) communicates with the ejector port H (described later) through this hollow section. More specifically, a flow path for fluid circulation is formed inside the fixed blade body 11, and the suction section 20 communicates with the ejector port H through this flow path.

[0041] A nozzle inner peripheral component 12 is provided on the radially inner side of the fixed blade body 11. The nozzle inner peripheral component 12 is annular about the axis Ac and supports multiple fixed blade bodies 11 arranged in the circumferential direction from the radially inner side.

[0042] The inner circumferential surface 12S of the nozzle inner circumferential component 12 is radially spaced apart from the outer circumferential surface 6S of the rotor body 6. A plurality of fixed blade sealing fins 13 are provided on the inner circumferential surface 12S. In this embodiment, as an example, three fixed blade sealing fins 13 are arranged at intervals along the axial direction Ac. However, the number of fixed blade sealing fins 13 is not limited to three; it can be four or more. Each fixed blade sealing fin 13 protrudes radially inward from the inner circumferential surface 12S and is an annular shape extending circumferentially. The fixed blade sealing fin 13 has a tapered cross-sectional shape whose dimensions gradually decrease from the radially outer side towards the inner axial direction Ac. A certain clearance is formed between the radially inner end of the fixed blade sealing fin 13 and the outer circumferential surface 6S of the rotor body 6.

[0043] Next, refer to Figure 4 The detailed structure of the fixed blade sealing fin 13 is described below. Figure 4 As shown, in this embodiment, among the three fixed blade sealing fins 13, the fixed blade sealing fin 13 located on the most upstream side is designated as the first sealing fin 13A, and the fixed blade sealing fin 13 located on the most downstream side is designated as the third sealing fin 13C. Furthermore, the fixed blade sealing fin 13 located between these first sealing fins 13A and third sealing fins 13C is designated as the second sealing fin 13B.

[0044] Of these three fixed-blade sealing fins 13, an outlet H communicating with the aforementioned intake 20 is formed at the front end (radially inward end) of the second sealing fin 13B. That is, although not shown in detail, a flow path communicating between the intake 20 and the outlet H is formed inside the second sealing fin 13B. Here, in the space S formed between the fixed-blade sealing fins 13, the static pressure becomes lower than that around the fixed-blade body 11 because the main flow of steam (i.e., the flow of steam around the fixed-blade body 11) is blocked by the fixed-blade sealing fins 13 themselves. That is, a pressure difference is generated between this space S and the area around the fixed-blade body 11. As a result, a portion of the steam around the fixed-blade body 11 is drawn in from the intake 20 toward the outlet H. The drawn-in steam A is ejected into the space S as a jet J from the outlet H.

[0045] (Structure of rotating blades)

[0046] like Figure 2 As shown, the rotating blade 8 has a disk 61, a rotating blade body 81, an outer protective cover 82, and rotating blade sealing fins 83. The disk 61 is annular about the axis Ac and is mounted on the outer circumferential surface 6S of the rotor body 6. Multiple rotating blade bodies 81 are arranged on the outer circumferential side of the disk 61. These rotating blade bodies 81 are arranged at intervals in the circumferential direction. Although not shown in detail, each rotating blade body 81 has a blade-like cross-sectional shape when viewed radially. An outer protective cover 82 is provided radially outward of the rotating blade body 81. The outer protective cover 82 is annular about the axis Ac and supports multiple rotating blade bodies 81 radially outward.

[0047] A plurality of rotating blade sealing fins 83 are provided on the outer peripheral surface 82S of the outer casing 82, arranged at intervals along the axial direction Ac. The rotating blade sealing fins 83 suppress the steam flow (leakage flow) flowing into the space between the outer casing 82 and the inner peripheral surface 3S. In this embodiment, as an example, four rotating blade sealing fins 83 are provided. However, the number of rotating blade sealing fins 83 is not limited to four; it may be three or less or five or more. Each rotating blade sealing fin 83 protrudes radially outward from the outer peripheral surface 82S and is annular in shape extending circumferentially. The rotating blade sealing fin 83 has a tapered cross-sectional shape whose dimensions gradually decrease from the radially inward side toward the outer axial direction Ac. A certain clearance is formed between the front end (radially outward end) of the rotating blade sealing fin 83 and the inner peripheral surface 3S of the casing 3.

[0048] (Effects)

[0049] Next, the operation of the steam turbine 1 according to the present embodiment will be described. When the steam turbine 1 is operated, high-temperature and high-pressure steam generated in an external boiler or the like is supplied from the steam supply port 40 into the casing 3. Most of the steam supplied into the casing 3 contacts the stationary blade layer 9 and the rotating blade layer 7 alternately while flowing from the upstream side toward the downstream side. The stationary blade layer 9 changes the flow direction of the steam and appropriately adjusts the inflow angle to the rotating blade layer 7. The steam flows into the rotating blade layer 7, and thus a rotational force is imparted to the rotor 2 via the rotating blade layer 7. As a result, the rotor 2 rotates around the axis Ac. The rotational energy of the rotor 2 is used, for example, to drive a generator (not shown) connected to the shaft end. The steam that has passed through the most downstream-side rotating blade layer 7 is guided to an external condenser or the like (not shown) via the steam discharge port 50.

[0050] Further, it is known that when steam passes around the stationary blade body 11, a flow layer called a boundary layer of low flow speed is formed on the surface of the stationary blade body 11 due to the viscosity of the steam. The boundary layer is particularly significantly generated on the trailing edge 11T side in the low-pressure surface 11B of the stationary blade body 11. Also, in the vicinity of the leading edge 11L of the stationary blade body 11, a vortex as a secondary flow that starts from the radial both ends is easily formed. Due to these phenomena, the smooth flow of the steam is hindered, and it is possible that the efficiency of the steam turbine 1 will decrease. In addition, there is a request to reduce the flow of steam (leakage flow) that flows between the stationary blade seal fins 13 and the outer peripheral surface 6S of the rotor body 6 to improve the efficiency of the turbine.

[0051] Therefore, in the present embodiment, a structure is adopted in which the boundary layer and the secondary flow are sucked in by the suction portions 20 described above and supplied to the space S between the stationary blade seal fins 13 as the jet flow J from the jet outlets H. In the region (space S) surrounded by the stationary blade seal fins 13, the static pressure is lower than in the region (main flow path) in which the main flow of the steam flows. Based on this pressure difference, a flow is formed from the suction portions 20 formed on the surface of the stationary blade body 11 toward the jet outlets H. Along with this flow, steam as the boundary layer or the secondary flow is sucked in from the suction portions 20. The steam sucked in from the suction portions 20 is ejected to the space S between the stationary blade seal fins 13 via the jet outlets H. As a result, the boundary layer or the secondary flow formed on the surface of the stationary blade body 11 is reduced. As a result, the energy loss around the stationary blade body 11 is suppressed, and it is possible to further improve the efficiency of the steam turbine 1.

[0052] Furthermore, there is a particular tendency for a boundary layer or secondary flow to form on the negative pressure surface 11B side of the fixed blade body 11. According to the above structure, the suction section 20 is formed further towards the negative pressure surface 11B than the leading edge 11L of the fixed blade body 11. This allows for more efficient intake of the boundary layer or secondary flow and further reduces energy loss. Moreover, according to this structure, since the opening of the suction section 20 is limited to the negative pressure surface 11B, a reduction in the strength of the fixed blade body 11 can be avoided, for example, compared to the case where the same opening is formed on the positive pressure surface 11A.

[0053] Furthermore, at a position on the negative pressure surface 11B that is biased towards the trailing edge 11T, there is a tendency for a boundary layer to develop particularly easily. According to the above structure, a trailing edge suction port 22 is formed at such a position where the boundary layer is prone to development. Because the boundary layer is drawn in through this trailing edge suction port 22, the steam flow becomes tightly adhered to the negative pressure surface 11B. As a result, the steam flow becomes smoother, further reducing the energy loss of the steam turbine 1.

[0054] Furthermore, in the radially inner and outer regions of the leading edge 11L side of the negative pressure surface 11B, there is a particular tendency for vortices to be generated as secondary flows. According to the above structure, a leading edge side intake 21 is formed at such a location where secondary flows are easily generated. Because secondary flows are drawn in through this leading edge side intake 21, the steam flow becomes even more tightly adhered to the negative pressure surface 11B. As a result, energy loss in the steam turbine 1 can be further suppressed.

[0055] Here, as Figure 4 As shown, within space S, a vortex V is formed by the leakage flow flowing in from the gap C between the fixed blade sealing fin 13 and the outer peripheral surface 6S of the rotor body 6. After flowing from the upstream side to the downstream side along the outer peripheral surface 6S, the vortex V changes direction radially outward along the fixed blade sealing fin 13 on the downstream side, and then flows back towards the upstream side along the inner peripheral surface 12S of the nozzle inner peripheral component 12.

[0056] In the above structure, an outlet H is formed at the radially inner end of the second sealing fin 13B counting from one side along the axis Ac. By ejecting a jet J from the outlet H, the leakage flow flowing in the gap C is obstructed, thus imparting a flow-constriction effect to the leakage flow. Furthermore, the jet J can impart a further rotational force to the aforementioned vortex V. As the vortex V further develops, the flow rate of the leakage flow entering the space S can be further reduced. In this way, by improving the sealing performance based on the fixed blade sealing fin 13, the efficiency of the steam turbine 1 can be further improved.

[0057] [Modifications of the First Embodiment]

[0058] The first embodiment of the present application has been described above. In addition, the above-described structure can be variously changed or modified without departing from the gist of the present application. For example, in the above-described first embodiment, the structure in which the leading edge side suction port 21 is provided in a pair at intervals in the radial direction has been described. However, as a first modified example, as shown in FIG. 10, it is also possible to form only one leading edge side suction port 21B extending over the entire region in the radial direction. According to this structure, since the leading edge side suction port 21 is formed over the entire region in the radial direction, it is possible to effectively suck the secondary flow in a larger range. Figure 5

[0059] Further, as a second modified example, as shown in FIG. 11, it is also possible to adopt a structure in which the leading edge side suction port 21 is not formed and only the trailing edge side suction port 22 is formed. According to this structure, it is possible to reduce the opening portion formed in the fixed blade body 11 by an amount corresponding to the amount in which the leading edge side suction port 21 is not formed, and thus it is possible to minimize the reduction in the strength of the fixed blade body 11 while achieving the reduction of the boundary layer. Figure 6

[0060] Further, as a third modified example, as shown in FIG. 12, it is also possible to adopt a structure in which the trailing edge side suction port 22 is not formed and only the leading edge side suction port 21 is formed. According to this structure, it is possible to simultaneously suck and reduce the secondary flow and the boundary layer by the leading edge side suction port 21. Also in this case, it is possible to reduce the opening portion formed in the fixed blade body 11, and thus it is possible to minimize the reduction in the strength of the fixed blade body 11 while achieving the reduction of the secondary flow and the boundary layer. Figure 7

[0061] [Second Embodiment]

[0062] Next, the second embodiment of the present application will be described with reference to FIGS. 13 to 15. In addition, the same symbols are attached to the same structures as those of the first embodiment, and detailed description will be omitted. As shown in FIG. 13, in the present embodiment, the position at which the jet port H1 is formed is different from that of the first embodiment. Figure 8 Figure 8

[0063] The jet port H1 opens on the inner peripheral surface 12S of the nozzle inner peripheral member 12. More specifically, the jet port H1 opens toward the space S between the first sealing fin 13A and the second sealing fin 13B. Further specifically, the jet port H1 is formed at a position in the space S that is biased toward the first sealing fin 13A side in the axial direction Ac. That is, by forming the jet flow J along the flow direction of the vortex flow V formed in the space S, it is possible to increase the rotation force of the vortex flow V. This jet port H1 communicates with the suction portion 20 described in the first embodiment through the flow path F. The flow path F penetrates the nozzle inner peripheral member 12 in the radial direction.

[0064] ​​​​​According to the above structure, steam can be supplied to the region (space S) between adjacent fixed blade sealing fins 13 through the nozzle outlet H1 formed on the inner circumferential surface 12S of the nozzle inner circumferential member 12. In particular, in this embodiment, the nozzle outlet H1 is formed in the space S at a position biased towards the first sealing fin 13A in the axial direction Ac. This promotes the formation of vortices V in the space S and increases their rotational force. Through the development of these vortices V, the flow rate of leakage flow into the space S is suppressed, thereby further improving the efficiency of the steam turbine 1.

[0065] The second embodiment of the present invention has been described above. Furthermore, various changes or modifications can be made to the above structure without departing from the spirit of the invention. For example, the position of the nozzle outlet H1 is not limited to the inner circumferential surface 12S described above; the nozzle outlet H1 can be formed at any position as long as it is a portion of the nozzle inner circumferential component 12 and the plurality of fixed blade sealing fins 13 that is further downstream than the first sealing fin 13A. That is, depending on the design or specifications, the nozzle outlet H1 can be formed on the inner circumferential surface 12S between the second sealing fin 13B and the third sealing fin 13C. Furthermore, the same nozzle outlet H as in the first embodiment can also be formed on the third sealing fin 13C itself. In addition, a structure in which the nozzle outlet H is formed only on the third sealing fin 13C can also be adopted.

[0066] [Third Implementation Method]

[0067] Next, refer to Figure 9 The third embodiment of the present invention will now be described. Furthermore, structures identical to those in the embodiments described above will be labeled with the same reference numerals, and detailed descriptions will be omitted. For example... Figure 9 As shown, in this embodiment, the position of the nozzle H2 in the fixed blade sealing fin 13 (second sealing fin 13B) differs from that in the first embodiment. In the first embodiment, the nozzle H is formed at the front end of the fixed blade sealing fin 13. In contrast, in this embodiment, the nozzle H2 is formed on the downstream-facing surface (downstream surface 13D) of the fixed blade sealing fin 13. In other words, the nozzle H2 is formed at a position further radially outward than the front end 13T (i.e., the radially inward end) of the fixed blade sealing fin 13. Furthermore, the distance from the base end 13R (i.e., the radially outward end) of the fixed blade sealing fin 13 to the nozzle H2 is greater than the distance from the front end 13T to the nozzle H2. That is, the nozzle H2 is formed at a position closer to the front end 13T than the base end 13R. Furthermore, the nozzle H2 is configured with an opening direction such that a jet stream J can be ejected radially inward.

[0068] According to the above structure, steam as jet J can be supplied to the region between adjacent fixed blade sealing fins 13 (space S: same as in the first embodiment) through the nozzle H2 formed on the downstream surface 13D of the fixed blade sealing fins 13. This promotes the formation of vortices within the space S. In particular, the nozzle H2 is formed at a position further radially outward than the front end 13T (i.e., the radially inner end) of the fixed blade sealing fins 13. Therefore, for example, compared to the case where the nozzle H2 is formed at the front end 13T, the jet J can be more integrated into the vortex flow. That is, the rotational force of the vortex can be further increased by the jet J, thereby promoting vortex development. Through vortex development, leakage flow flowing in the aforementioned gap C is reduced, thereby further improving the efficiency of the steam turbine 1.

[0069] [Modifications of the Third Embodiment]

[0070] The third embodiment of the present invention has been described above. Furthermore, various changes or modifications can be made to the above structure without departing from the spirit of the present invention. For example, as a first variation of the third embodiment, such as... Figure 10 As shown, the opening direction of the nozzle H3 can also be set by ejecting the jet stream J towards the downstream side. Furthermore, as a second variation, as... Figure 11 As shown, the nozzle H4, which ejects the jet J downstream, can also be formed near the base end 13R. Furthermore, the opening direction of the nozzle H3 (H4) only needs to include a downstream component, for example... Figure 12 As shown, the opening direction can also be set such that the jet J forms radially inward as it moves towards the downstream side. Furthermore, the opening direction can also be set such that the jet J forms radially outward as it moves towards the downstream side. According to these structures, in addition to promoting the formation of vortices, the flow rate of the leakage flow into the space S can be further reduced. As a result, the efficiency of the steam turbine 1 can be further improved.

[0071] [Common variations to all implementation methods]

[0072] Furthermore, in the above embodiments, the structure of the fixed blade 10 was described using a steam turbine 1 as an example. However, the structure corresponding to the fixed blade 10 (inlet 20 and outlet H, outlet H1, outlet H2, outlet H3, outlet H4) is not limited to the steam turbine 1, and can be applied to the turbine section of a gas turbine.

[0073] [Postscript]

[0074] The steam turbine 1 described in each embodiment is as follows.

[0075] (1) The steam turbine 1 according to the first aspect includes: a rotor 2 having a rotor main body 6 rotatable about an axis Ac and a plurality of rotor blades 8 arranged in a circumferential direction along an outer peripheral surface 6S of the rotor main body 6; a casing 3 covering the rotor 2; and a plurality of stationary blades 10 arranged in the circumferential direction along an inner peripheral surface 3S of the casing 3, the stationary blade 10 having: a stationary blade main body 11 in which a suction portion 20 is formed on a surface, the suction portion 20 extending in a radial direction with respect to the axis Ac and being able to suck at least a part of a working fluid flowing from one side to the other side in the axis Ac direction; a nozzle inner peripheral member 12 provided on a radially inner side of the stationary blade main body 11; and a plurality of seal fins (stationary blade seal fins 13) protruding from an inner peripheral surface 12S of the nozzle inner peripheral member 12 toward a radially inner side and arranged at intervals in the axis Ac direction, a portion of the nozzle inner peripheral member 12 and the seal fins on the other side than the seal fin on the most one side in the axis Ac direction being formed with a discharge port H discharging the working fluid introduced from the suction portion 20.

[0076] In a region surrounded by the plurality of seal fins (stationary blade seal fins 13), the static pressure is lower than that in a region in which the main flow of the steam flows (main flow path). Based on this pressure difference, a part of the working fluid is sucked toward the discharge port H from the suction portion 20 formed on the surface of the stationary blade main body 11. Thus, the boundary layer or the secondary flow formed on the surface of the stationary blade main body 11 can be sucked. As a result, energy loss generated around the stationary blade main body 11 can be suppressed.

[0077] (2) In the steam turbine 1 according to the second aspect, the suction portion 20 can also be formed on the negative pressure surface 11B side than the leading edge 11L of the stationary blade main body 11.

[0078] On the negative pressure surface 11B side, there is a tendency to particularly easily form a boundary layer or a secondary flow. According to the above structure, the suction portion 20 is formed on the negative pressure surface 11B side than the leading edge 11L of the stationary blade main body 11. Thus, the boundary layer or the secondary flow can be more effectively sucked, and energy loss can be further reduced.

[0079] (3) In the steam turbine 1 according to the third aspect, the suction portion 20 can also have a trailing edge side suction port 22 formed at a position deviated toward the trailing edge 11T side in the negative pressure surface 11B of the stationary blade main body 11 and extending over the entire region in the radial direction.

[0080] In the position of the suction port 22 on the side of the trailing edge 11T in the negative pressure surface 11B, there is a tendency that the boundary layer is particularly likely to develop. According to the above structure, the trailing edge side suction port 22 is formed in the position where the boundary layer is likely to develop. Since the boundary layer is sucked through the trailing edge side suction port 22, energy loss can be further reduced.

[0081] (4) In the steam turbine 1 according to the 4th aspect, the suction portion 20 can also have a leading edge side suction port 21 formed in a position on the side of the leading edge 11L in the negative pressure surface 11B of the fixed vane main body 11 and located at least one of a radially inner portion and a radially outer portion.

[0082] In the radially inner and outer regions of the leading edge 11L side in the negative pressure surface 11B, there is a tendency that vortex flow as a secondary flow is particularly likely to occur. According to the above structure, the leading edge side suction port 21 is formed in the position where the secondary flow is likely to occur. Since the secondary flow is sucked through the leading edge side suction port 21, energy loss can be further suppressed.

[0083] (5) In the steam turbine 1 according to the 5th aspect, the leading edge side suction port 21 can also extend over the entire region in the radial direction.

[0084] According to the above structure, since the leading edge side suction port 21 is formed over the entire region in the radial direction, the secondary flow can be effectively sucked in a larger range.

[0085] (6) In the steam turbine 1 according to the 6th aspect, the injection port H1 can also be formed in the inner peripheral surface 12S of the nozzle inner peripheral member 12.

[0086] According to the above structure, the working fluid can be supplied to the region (space S) between the adjacent seal fins (fixed vane seal fins 13) through the injection port H1 formed in the inner peripheral surface 12S of the nozzle inner peripheral member 12. Thus, the formation of vortex flow in the region can be promoted. By the development of the vortex flow, the flow of the leakage flow is reduced, and thus the efficiency of the steam turbine 1 can be further improved.

[0087] (7) In the steam turbine 1 according to the 7th aspect, the injection port H can also be formed in the radially inner end portion of the seal fin (fixed vane seal fin 13) that is the second or later from the side of the axis Ac.

[0088] According to the above structure, the end portion of the 2nd seal fin from the radial inner side is formed with the injection port H from the side of the axis Ac direction. Thereby, the leakage flow flowing in the gap formed between the seal fin and the rotor main body 6 can be given the flow contraction effect. As a result, the leakage flow is reduced, and the efficiency of the steam turbine 1 can be further improved.

[0089] (8) In the steam turbine 1 according to the 8th aspect, the injection port H2 can also be formed in the face of the seal fin (fixed blade seal fin 13) of the plurality of seal fins toward the other side of the axis Ac direction from the side of the axis Ac direction, and configured to inject the working fluid toward the radial inner side.

[0090] According to the above structure, the working fluid can be supplied to the region (space S) between the adjacent seal fins through the injection port H2 formed in the face toward the downstream side of the seal fin. Thereby, the formation of the vortex in the region can be promoted. By the development of the vortex, the leakage flow is reduced, and the efficiency of the steam turbine 1 can be further improved.

[0091] (9) In the steam turbine 1 according to the 9th aspect, the injection port H3 can also be formed in the face of the seal fin (fixed blade seal fin 13) of the plurality of seal fins toward the other side of the axis Ac direction from the side of the axis Ac direction, and configured to inject the working fluid with a directional component toward the other side of the axis Ac direction.

[0092] According to the above structure, the working fluid can be supplied to the region (space S) between the adjacent seal fins through the injection port H3 formed in the face toward the downstream side of the seal fin. In particular, the working fluid is injected from the injection port H3 with a directional component toward the downstream side. Thereby, the leakage flow through the region can be further reduced. As a result, the efficiency of the steam turbine 1 can be further improved.

[0093] Industrial Applicability

[0094] According to the present application, a steam turbine with further improved efficiency can be provided.

[0095] Explanation of Symbols

[0096] 1 - steam turbine, 2 - rotor, 3 - casing, 3S - inner peripheral surface, 4 - journal bearing, 5 - thrust bearing, 6 - rotor main body, 6S - outer peripheral surface, 7 - rotor blade row, 8 - rotor blade, 9 - stator blade row, 10 - stator blade, 11 - stator blade main body, 11A - pressure surface, 11B - suction surface, 11L - leading edge, 11T - trailing edge, 12 - nozzle inner peripheral member, 12S - inner peripheral surface, 13 - stator blade seal fin, 13A - first seal fin, 13B - second seal fin, 13C - third seal fin, 13D - downstream surface, 13R - base end, 13T - tip end, 20 - suction portion, 21, 21B - leading edge side suction port, 22 - trailing edge side suction port, 31 - nozzle outer peripheral member, 40 - steam supply port, 50 - steam discharge port, 61 - wheel disk, 81 - rotor blade main body, 82 - outer shroud, 82S - outer peripheral surface, 83 - rotor blade seal fin, Ac - axis, C - clearance, CL - camber line, F - flow path, H, H1, H2, H3, H4 - discharge port, J - jet, S - space, V - vortex.

Claims

1. A turbine having: The rotor has a rotor body that can rotate about an axis and a plurality of rotating blades arranged circumferentially along the outer circumferential surface of the rotor body; Housing, covering the rotor; and Multiple fixed blades are arranged circumferentially along the inner circumferential surface of the housing. The fixed blade has: A fixed blade body has an intake portion formed on its surface, the intake portion extending radially relative to the axis and capable of drawing in at least a portion of the working fluid flowing from one side of the axis toward the other; The nozzle inner peripheral component is located radially inside the fixed blade body; and Multiple sealing fins protrude radially inward from the inner circumferential surface of the nozzle's inner circumferential component and are arranged at intervals along the axial direction. A nozzle outlet is formed on the inner circumferential component of the nozzle and on the portion of the sealing fin that is further away from the side of the sealing fin than the side furthest in the axial direction, to eject the working fluid introduced from the suction section. The suction section has a pair of leading-edge side suction ports that are radially separated from each other. One leading-edge side suction port is formed near the radially outer end of the negative pressure surface of the fixed blade body, and the other leading-edge side suction port is formed near the radially inner end of the negative pressure surface.

2. The turbine according to claim 1, wherein, The suction section is formed on the negative pressure side, which is closer to the leading edge of the fixed blade body.

3. The turbine according to claim 1, wherein, The suction section has a trailing edge suction port, which is formed on the negative pressure surface of the fixed blade body at a position biased towards the trailing edge and extends throughout the entire radial region.

4. The turbine according to claim 2, wherein, The suction section has a trailing edge suction port, which is formed on the negative pressure surface of the fixed blade body at a position biased towards the trailing edge and extends throughout the entire radial region.

5. The turbine according to claim 1, wherein, The suction section has a leading-edge side suction port, which is formed on at least one of the radially inner and outer portions of the negative pressure surface of the fixed blade body, located on the front edge side.

6. The turbine according to claim 2, wherein, The suction section has a leading-edge side suction port, which is formed on at least one of the radially inner and outer portions of the negative pressure surface of the fixed blade body, located on the front edge side.

7. The turbine according to claim 3, wherein, The suction section has a leading-edge side suction port, which is formed on at least one of the radially inner and outer portions of the negative pressure surface of the fixed blade body, located on the front edge side.

8. The turbine according to claim 4, wherein, The suction section has a leading-edge side suction port, which is formed on at least one of the radially inner and outer portions of the negative pressure surface of the fixed blade body, located on the front edge side.

9. The turbine according to any one of claims 5 to 8, wherein, The leading edge side intake extends throughout the entire radial region.

10. The turbine according to any one of claims 1 to 8, wherein, The nozzle outlet is formed on the inner circumferential surface of the nozzle inner circumferential component.

11. The turbine according to any one of claims 1 to 8, wherein, The nozzle is formed at the radially inner end of the second or subsequent sealing fin, which is one of the plurality of sealing fins, counting from one side along the axial direction.

12. The turbine according to any one of claims 1 to 8, wherein, The nozzle is formed on the surface of the second or subsequent sealing fins in the axial direction, facing the other side of the axial direction, and is configured to spray working fluid in a radially inward direction.

13. The turbine according to any one of claims 1 to 8, wherein, The nozzle is formed on the surface of the second or subsequent sealing fins in the axial direction, facing the other side of the axial direction, and is configured to eject working fluid along with a directional component facing the other side of the axial direction.

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