Steam turbine

Abstract

To guide a water droplet efficiently to an opening without depending on a steam flow of a main flow passage.SOLUTION: A steam turbine has a plurality of steps constituted of a pair of a rotor blade and a stationary blade aligned in an axial direction. A casing has a casing opening that opens on an inner peripheral face facing a tip of the rotor blade on a second side in the axial direction with respect to the rotor blade and into which the water droplet circulated in a main flow path flows. The rotor blade has a plurality of rotor blade hydrophilic parts that are formed with an interval therebetween in a radial direction with respect to a rotor blade face extending in the radial direction and guide the water droplet attached on the rotor blade face toward the casing opening. The stationary blade has: a drain suction port that opens on a stationary blade face extending in the radial direction and into which the water droplet attached on the stationary blade face flows; and a plurality of stationary blade hydrophilic parts that are formed with an interval therebetween in the radial direction with respect to the stationary blade face and guide the water droplet attached on the stationary blade face toward the drain suction port.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to steam turbines. [Background technology]

[0002] A steam turbine includes a rotor (turbine rotor) disposed within a casing, a row of moving blades provided on the radial outside of the rotor, and a row of stator blades provided on the radial inside of the casing.

[0003] In a steam turbine, the pressure becomes very low as it approaches the final stage. Therefore, the steam circulating eventually reaches saturated vapor pressure and becomes wet steam containing tiny liquefied water droplets (water droplet nuclei). Most of these tiny water droplets (drainage) pass between the moving blades and stationary blades along with the steam, but some adhere to the blade surface due to inertia. The water droplets that adhere to the blade surface form a liquid film on the blade surface.

[0004] In response to this, for example, Patent Document 1 describes a steam turbine in which band-shaped hydrophobic regions and band-shaped hydrophilic regions are alternately arranged on at least a part of the blade surface of the stator vane. In the steam turbine stator vane of Patent Document 1, water on the blade surface is guided from the outside to the inside in the radial direction, suppressing the frequency of erosion and the progress speed of erosion in the rotor blades arranged downstream. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-20443 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the steam turbine as described above, in order to remove the drainage, an opening is formed in the blades and the casing to discharge the drainage from the main flow path through which the steam flows. In a steam turbine having such a structure, it is required to guide the water droplets to the opening without relying on the flow of steam in the main flow path.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a steam turbine that can efficiently guide water droplets to an opening without relying on the steam flow in the main flow path. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, a steam turbine according to the present disclosure includes a rotor shaft rotatable about an axis, a plurality of moving blades fixed to the outside of the rotor shaft in a radial direction based on the axis, a casing covering the rotor shaft and the plurality of moving blades from the outside in the radial direction and having a main flow passage through which steam can flow, and a plurality of stator vanes fixed to the inside of the casing in the radial direction and arranged on a first side in the axial direction with respect to the plurality of moving blades, the casing having a plurality of stages formed by pairs of the moving blades and the stator vanes lined up in the axial direction, and the casing has a plurality of stages formed by pairs of the moving blades and the stator vanes aligned ... the casing having a plurality of moving blades fixed to the inside of the casing in the radial direction with respect to the second side in the axial direction with respect to the moving blades, The rotor blades arranged in at least one of the stages have a casing opening which opens on an inner circumferential surface opposite the tip of the blade and into which water droplets flowing through the main flow passage can flow, and the rotor blades arranged in at least one of the stages have a plurality of rotor blade hydrophilic portions which are formed at intervals in the radial direction with respect to the rotor blade surface extending in the radial direction and guide the water droplets adhering to the rotor blade surface toward the casing opening, and the stator blades arranged in at least one of the stages have a drain suction port which opens on the radially extending stator blade surface and into which the water droplets adhering to the stator blade surface can flow, and a plurality of stator blade hydrophilic portions which are formed at intervals in the radial direction with respect to the stator blade surface and guide the water droplets adhering to the stator blade surface toward the drain suction port. Effect of the Invention

[0009] According to the steam turbine of the present disclosure, water droplets can be efficiently guided to the opening without relying on the flow of steam in the main flow path. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing an overall configuration of a steam turbine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing a row of rotor blades and a row of stator blades of the steam turbine. [Diagram 3] FIG. 2 is a cross-sectional view showing a stationary blade having a hydrophilic portion and a moving blade having a hydrophilic portion of the steam turbine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of a steam turbine according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiment.

[0012] (Steam turbine configuration) As shown in FIG. 1, the steam turbine 1 of this embodiment has a rotor 20 that rotates about an axis Ar, a casing 10 that rotatably covers the rotor 20, and a plurality of stator blade rows 41.

[0013] For the convenience of the following description, the direction in which the axis Ar extends is referred to as the axial direction Da. The first side of the axial direction Da is referred to as the upstream side (one side) Dau, and the second side of the axial direction Da is referred to as the downstream side (the other side) Dad. The radial direction Dr of the rotor 20 based on the axis Ar is simply referred to as the radial direction Dr. The side of the radial direction Dr that approaches the axis Ar is referred to as the inner side Dri of the radial direction Dr, and the side of the radial direction Dr opposite to the inner side Dri of the radial direction Dr is referred to as the outer side Dro of the radial direction Dr. The circumferential direction of the rotor 20 centered on the axis Ar is simply referred to as the circumferential direction Dc.

[0014] As shown in FIGS. 1 and 2, the rotor 20 has a rotor shaft 21 and a plurality of rotor blade rows 31.

[0015] The rotor shaft 21 is rotatable about the axis Ar relative to the casing 10. The rotor shaft 21 has a core portion 22 and a plurality of disk portions 23. The core portion 22 is formed in a cylindrical shape centered on the axis Ar and extends in the axial direction Da. The disk portions 23 extend from the core portion 22 to the outside Dro in the radial direction Dr. The disk portions 23 are arranged at intervals from one another in the axial direction Da. The disk portions 23 are arranged for each of the plurality of rotor blade rows 31.

[0016] The rotor blade row 31 is fixed to the outside Dro of the rotor shaft 21 in the radial direction Dr. Specifically, as shown in FIG. 2, the rotor blade row 31 is fixed to the outside Dro of the disk portion 23, which is the outer circumferential portion of the rotor shaft 21, in the radial direction Dr. A plurality of rotor blade rows 31 are arranged at intervals in the axial direction Da of the rotor shaft 21. In the case of this embodiment, for example, a total of seven rotor blade rows 31 are arranged from the rotor blade row 31 located on the most upstream side Dau in the axial direction Da to the rotor blade row 31 located on the most downstream side Dad in the axial direction Da. Each rotor blade row 31 has a plurality of rotor blades 32 arranged in the circumferential direction Dc. The plurality of rotor blades 32 are fixed to the outside Dro of the rotor shaft 21 in the radial direction Dr. The plurality of rotor blades 32 are respectively attached to the disk portion 23. Each rotor blade 32 extends from the disk portion 23 to the outside Dro in the radial direction Dr. Each rotor blade 32 is arranged in a main flow path 15 described later. Each rotor blade 32 has an airfoil-shaped cross section when viewed from the outside Dro in the radial direction Dr.

[0017] The casing 10 is formed so as to cover the rotor shaft 21 and the plurality of moving blades 32 from the outside Dro in the radial direction Dr. Inside the casing 10, a main flow passage 15 through which the steam S can flow is formed. Specifically, the casing 10 is formed with a nozzle chamber 11 into which the steam S flows from the outside, a flow passage chamber 12 through which the steam S from the nozzle chamber 11 flows, and an exhaust chamber 13 through which the steam S flowing from the flow passage chamber 12 is exhausted. Between the nozzle chamber 11 and the flow passage chamber 12, the moving blade row 31 and the stator blade row 41 of the first stage 50A on the most upstream side Dau are arranged among the plurality of moving blade rows 31 and the stator blade row 41. In other words, the inside of the casing 10 is divided into the nozzle chamber 11 and the flow passage chamber 12 by the moving blade row 31 and the stator blade row 41 on the most upstream side Dau. The nozzle chamber 11, the flow passage chamber 12, and the exhaust chamber 13 form the main flow passage 15 through which the high-pressure steam S flows.

[0018] The casing 10 further includes an exhaust casing 51 and a diffuser 70 .

[0019] The exhaust casing 51 is connected to the outside of the casing 10. The exhaust casing 51 exhausts the steam S that has flowed through the main flow path 15 to the outside of the casing 10. The exhaust casing 51 is disposed on the most downstream side Dad in the axial direction Da of the casing 10. An exhaust chamber 13 that opens downward is formed in the lower part of the exhaust casing 51. The exhaust casing 51 exhausts to the outside the steam S whose static pressure has been restored by a diffuser 70 described later.

[0020] The diffuser 70 guides the steam S flowing out from the rotor blade row 31 of the seventh stage 50G to the outside of the casing 10 via the exhaust chamber 13. The diffuser 70 is disposed between the rotor blade row 31 of the seventh stage 50G and the exhaust casing 51 that forms the exhaust chamber 13 in the casing 10.

[0021] In the main flow passage 15, high-pressure steam S flows from the upstream side Dau to the downstream side Dad while the pressure gradually decreases. The main flow passage 15 is annular around the rotor shaft 21. The main flow passage 15 extends in the axial direction Da across a plurality of rotor blade rows 31 and stator blade rows 41. A part of the main flow passage 15 is formed by an annular space in which stator blades 42, which will be described later, are arranged.

[0022] The stator blade row 41 is fixed to the inside Dri of the casing 10 in the radial direction Dr. The stator blade row 41 is provided with a plurality of stator blade rows 41. The stator blade rows 41 are arranged at intervals in the axial direction Da. In this embodiment, for example, a total of seven stator blade rows 41 are arranged from the stator blade row 41 located on the most upstream side Dau in the axial direction Da to the stator blade row 41 located on the most downstream side Dad in the axial direction Da. Each stator blade row 41 is arranged next to the upstream side Dau with respect to a corresponding one of the rotor blade rows 31.

[0023] Each stator blade row 41 has a plurality of stator blades 42 arranged in the circumferential direction Dc. The stator blades 42 are arranged at intervals in the circumferential direction Dc. The stator blades 42 are fixed to the inside Dri of the casing 10 in the radial direction Dr. The stator blades 42 are fixed to the inner circumferential surface of the casing 10. The inner circumferential surface of the casing 10 is a surface of the casing 10 facing the inside Dri in the radial direction Dr and facing the main flow passage 15. The inner circumferential surface of the casing 10 is a surface that faces the tips of the rotor blades 32 at a position shifted in the axial direction Da from the position where the stator blades 42 are fixed.

[0024] A stage 50 is formed by each set of a rotor blade row 31 and a stator blade row 41 arranged on the upstream side Dau of the rotor blade row 31. That is, one stage 50 is formed by a pair of a rotor blade 32 and a stator blade 42 arranged in the axial direction Da. Therefore, a plurality of stator blades 42 arranged in the circumferential direction Dc are arranged on the upstream side Dau in the axial direction Da with respect to a plurality of rotor blades 32 arranged in the circumferential direction Dc. In the steam turbine 1 of this embodiment, a stator blade row 41 is arranged for each of seven rotor blade rows 31 in FIG. 2. Therefore, the steam turbine 1 of this embodiment has seven stages 50. That is, the steam turbine 1 of this embodiment has the rotor blade rows 31 and the stator blade rows 41 of the first stage 50A, the second stage 50B, the third stage 50C, the fourth stage 50D, the fifth stage 50E, the sixth stage 50F, and the seventh stage 50G in order from the upstream side Dau to the downstream side Dad.

[0025] As shown in FIG. 3, in the steam turbine 1 of this embodiment, the casing 10 has a casing opening 17 into which water droplets flowing through the main flow passage 15 can flow. The casing opening 17 is a drain catcher that discharges water droplets that have moved to the outside Dro in the radial direction Dr in the main flow passage 15 to the outside. The casing opening 17 opens on the inner circumferential surface of the casing 10 facing the tip of the rotor blade 32. The casing opening 17 opens on the downstream side Dad in the axial direction Da with respect to the rotor blade 32 with respect to at least one stage 50, and on the upstream side Dau in the axial direction Da with respect to the stator blade 42 of the next stage 50 located further downstream Da. Therefore, the casing opening 17 is formed between adjacent stages 50 in the axial direction Da. In this embodiment, the casing opening 17 is arranged on the downstream side Dad in the axial direction Da with respect to the rotor blades 32 of the fifth stage 50E and the sixth stage 50F. That is, the casing opening 17 is disposed downstream Dad in the axial direction Da with respect to the rotor blades 32 of the fifth stage 50E, and upstream Dau in the axial direction Da with respect to the stator blades 42 of the sixth stage 50F. Also, the casing opening 17 is disposed downstream Dad in the axial direction Da with respect to the rotor blades 32 of the sixth stage 50F, and upstream Dau in the axial direction Da with respect to the stator blades 42 of the seventh stage 50G. The casing opening 17 is disposed on the outer side Dro in the radial direction Dr with respect to the rotor blades 32. As a result, water droplets scattered by the rotor blades 32 toward the outer side Dro in the radial direction Dr flow into the casing opening 17.

[0026] In addition, the rotor blades 32 arranged in at least one stage 50 in this embodiment have a plurality of rotor blade hydrophilic portions 3A on their own blade surface 30. In this embodiment, the rotor blades 32 in the fifth stage 50E and the sixth stage 50F have the rotor blade hydrophilic portions 3A, but the sixth stage 50F will be described as an example.

[0027] Each of the moving blade hydrophilic parts 3A guides water droplets adhering to the moving blade surface 30 toward the casing opening 17. The moving blade hydrophilic parts 3A are formed to be more hydrophilic than the moving blade surface 30. In other words, water droplets are more likely to adhere to the moving blade hydrophilic parts 3A than to the moving blade surface 30. The moving blade hydrophilic parts 3A have a small surface contact angle with respect to the adhering water droplets in order to increase the hydrophilicity of the moving blade surface 30. Specifically, the moving blade hydrophilic parts 3A are formed by subjecting the moving blade surface 30 to a surface treatment such as coating, etching, ultraviolet irradiation, blasting, or oxygen plasma. The moving blade hydrophilic parts 3A extend in a straight line inclined with respect to the axis Ar toward the casing opening 17. The moving blade hydrophilic parts 3A extend without gaps in the axial direction Da from the leading edge to the trailing edge of the moving blade 32. A plurality of (five in this embodiment) rotor blade hydrophilic portions 3A are formed at intervals in the radial direction Dr with respect to the rotor blade surface 30 extending in the radial direction Dr. That is, the plurality of rotor blade hydrophilic portions 3A are formed apart from each other so as not to overlap each other in the radial direction Dr. As a result, the plurality of rotor blade hydrophilic portions 3A are formed in stripes aligned in the radial direction Dr when viewed from the circumferential direction Dc. When viewed from the circumferential direction Dc, the inclination of the plurality of rotor blade hydrophilic portions 3A with respect to the axis Ar is increased as the rotor blade hydrophilic portions 3A are disposed closer to the rotor shaft 21 in the radial direction Dr. That is, the rotor blade hydrophilic portions 3A extending from the vicinity of the root of the rotor blade 32 extend at an angle nearly perpendicular to the axis Ar so as to extend in the radial direction Dr. On the other hand, the rotor blade hydrophilic portions 3A extending from the vicinity of the tip of the rotor blade 32 extend at an angle nearly parallel to the axis Ar so as to extend in the axial direction Da. The plurality of bucket hydrophilic portions 3A are formed over the entire bucket surface 30 in the radial direction Dr.

[0028] Moreover, in this embodiment, the stator vane 42 arranged in at least one stage 50 has a drain inlet 45 and a plurality of stator vane hydrophilic portions 4A on its own blade surface, that is, the stator vane surface 40. In this embodiment, the stator vanes 42 in the fifth stage 50E and the sixth stage 50F have the drain inlet 45 and the stator vane hydrophilic portion 4A. That is, the stator vane 42 forming the stage 50 with the rotor blade 32 having the rotor blade hydrophilic portion 3A has the drain inlet 45 and the stator vane hydrophilic portion 4A.

[0029] The drain suction port 45 allows water droplets adhering to the stator blade surface 40 to flow in. The drain suction port 45 is open on the stator blade surface 40 extending in the radial direction Dr. The drain suction port 45 sends the collected water droplets to a drain collection path (not shown) formed inside the stator blade 42, and discharges the water droplets adhering to the stator blade surface 40 to the outside. The drain suction port 45 is formed in the radial direction Dr from near the center of the stator blade 42 to the end of the outer side Dro in the radial direction Dr. In other words, the drain suction port 45 is formed on the stator blade surface 40 like one long groove extending in the radial direction Dr. The drain suction port 45 is formed in a position closer to the trailing edge than the center of the stator blade 42 in the axial direction Da.

[0030] Each of the stator blade hydrophilic portions 4A guides water droplets adhering to the stator blade surface 40 toward the drain inlet 45. The stator blade hydrophilic portion 4A is formed to have a higher hydrophilicity than the stator blade surface 40. In other words, water droplets are more likely to adhere to the stator blade hydrophilic portion 4A than to the stator blade surface 40. The stator blade hydrophilic portion 4A has the same degree of hydrophilicity as the moving blade hydrophilic portion 3A of the moving blade 32 arranged downstream. The stator blade hydrophilic portion 4A has a small surface contact angle with respect to the adhering water droplets in order to increase the hydrophilicity of the stator blade surface 40. Specifically, the stator blade hydrophilic portion 4A is formed by subjecting the stator blade surface 40 to a surface treatment such as coating, etching, ultraviolet irradiation, blasting, oxygen plasma, or the like. The stator blade hydrophilic portion 4A may be formed by the same method as the moving blade hydrophilic portion 3A, or may be formed by a different method. The stator blade hydrophilic portion 4A extends in a straight line inclined with respect to the axis Ar toward the drain suction port 45. The stator blade hydrophilic portion 4A extends from the leading edge of the stator blade 42 to the drain suction port 45 without any gaps in the axial direction Da. The plurality of stator blade hydrophilic portions 4A (five in this embodiment) are formed at intervals in the radial direction Dr with respect to the stator blade surface 40 extending in the radial direction Dr. In other words, the plurality of stator blade hydrophilic portions 4A are formed apart from each other so as not to overlap each other in the radial direction Dr. As a result, the plurality of stator blade hydrophilic portions 4A are formed in stripes aligned in the radial direction Dr when viewed from the circumferential direction Dc. When viewed from the circumferential direction Dc, the inclination of the plurality of stator blade hydrophilic portions 4A with respect to the axis Ar is increased as the stator blade hydrophilic portions 4A are disposed closer to the rotor shaft 21 in the radial direction Dr. That is, the stator vane hydrophilic portion 4A extending from near the root of the rotor blade 32 extends in the radial direction Dr at an angle nearly perpendicular to the axis Ar. On the other hand, the stator vane hydrophilic portion 4A extending from near the tip of the rotor blade 32 extends in the axial direction Da at an angle nearly parallel to the axis Ar. The multiple stator vane hydrophilic portions 4A are formed over the entire stator vane surface 40 in the radial direction Dr. Also, when viewed from the circumferential direction Dc, the inclination of the stator vane hydrophilic portion 4A is smaller than the inclination of the rotor vane hydrophilic portion 3A formed on the rotor blade 32 arranged on the downstream side Dad and arranged at a position overlapping in the radial direction Dr.In other words, when viewed from the circumferential direction Dc, and comparing the inclination of the stator blade hydrophilic portion 4A and the rotor blade hydrophilic portion 3A, which are positioned side by side in the axial direction Da, the inclination of the rotor blade hydrophilic portion 3A is formed to be greater than the inclination of the stator blade hydrophilic portion 4A.

[0031] (Action and effect) In the steam turbine 1 having the above configuration, the stator vanes 42 and the rotor blades 32 are disposed in the main flow passage 15 through which the steam S flows from the upstream side Dau to the downstream side Dad in the axial direction Da. In the main flow passage 15, water droplets are generated in the steam S as the pressure of the steam S decreases. Therefore, water droplets are more likely to be generated as the steam S approaches the final stage 50G on the downstream side Dad. As a result, the steam S flows through the main flow passage 15 in a state containing water droplets. When the steam S flows near the stator vanes 42 and the rotor blades 32, the water droplets in the steam S adhere to the stator blade surface 40 and the rotor blade surface 30 as fine water droplets due to inertia. As a result, water droplets (drainage) adhere to the stator blade surface 40 and the rotor blade surface 30. The water droplets attached to the stator blade surface 40 and the rotor blade surface 30 flow along the stator blade surface 40 and the rotor blade surface 30 from the leading edge to the trailing edge so as to form a liquid film.

[0032] Specifically, the water droplets adhering to the stator blade surface 40 come into contact with the stator blade hydrophilic portion 4A on the way to the end of the trailing edge. The water droplets that have come into contact with the stator blade hydrophilic portion 4A do not return to the stator blade surface 40 where the stator blade hydrophilic portion 4A is not formed, but continue to flow over the stator blade hydrophilic portion 4A, because the hydrophilicity of the stator blade hydrophilic portion 4A is higher than that of the stator blade surface 40. Here, the multiple stator blade hydrophilic portions 4A are formed to guide the water droplets toward the drain suction port 45. Therefore, the water droplets that have flowed over the stator blade hydrophilic portion 4A flow from the stator blade hydrophilic portion 4A into the drain suction port 45 formed in the stator blade 42 itself on the way to the end of the trailing edge. The water droplets that have flowed into the drain suction port 45 are discharged to the outside of the casing 10.

[0033] At this time, the stator blade hydrophilic portion 4A is formed at intervals in the radial direction Dr with respect to the stator blade surface 40. Therefore, even if the steam S gathers and flows at any position in the radial direction Dr with respect to the stator blade surface 40, the steam S can come into contact with any of the multiple stator blade hydrophilic portions 4A. In addition, since the multiple linearly extending stator blade hydrophilic portions 4A are finely arranged at intervals in the radial direction Dr, water droplets attached to the stator blade hydrophilic portion 4A can be easily guided in an intended direction compared to a case where one hydrophilic portion is formed large to cover a wide area of ​​the stator blade surface 40. In other words, the flow of water droplets attached to the stator blade hydrophilic portion 4A extending linearly toward the drain inlet 45 can be stably guided toward the drain inlet 45. Therefore, the steam S is less susceptible to the influence of the flow field of the stator blade surface 40, which changes depending on the operating conditions of the steam turbine 1, and the liquid droplets and liquid film on the stator blade hydrophilic portion 4A can stably flow into the drain inlet 45.

[0034] In addition, the water droplets adhering to the moving blade surface 30 come into contact with the moving blade hydrophilic portion 3A on the way to the end of the trailing edge. The water droplets that come into contact with the moving blade hydrophilic portion 3A do not return to the moving blade surface 30 where the moving blade hydrophilic portion 3A is not formed, because the hydrophilicity of the moving blade hydrophilic portion 3A is higher than that of the moving blade surface 30, and continue to flow on the moving blade hydrophilic portion 3A. Here, the multiple stationary blade hydrophilic portions 4A are formed to guide the water droplets toward the casing opening 17. Therefore, when the water droplets that flow on the moving blade hydrophilic portion 3A leave the end of the trailing edge, they are blown away with momentum toward the casing opening 17. Therefore, after the water droplets that flow on the moving blade hydrophilic portion 3A leave the end of the trailing edge, they flow into the casing opening 17 formed adjacent to the casing opening 17 in the axial direction Da. The water droplets that flow into the casing opening 17 are discharged to the outside of the casing 10.

[0035] At this time, the rotor blade hydrophilic portion 3A is formed at intervals in the radial direction Dr with respect to the rotor blade surface 30. Therefore, even if the steam S gathers and flows at any position in the radial direction Dr with respect to the rotor blade surface 30, the steam S can be brought into contact with any of the multiple rotor blade hydrophilic portions 3A. In addition, since the multiple linearly extending rotor blade hydrophilic portions 3A are finely arranged at intervals in the radial direction Dr, water droplets attached to the rotor blade hydrophilic portion 3A can be easily guided in an intended direction compared to a case where one hydrophilic portion is formed large to cover a wide area of ​​the rotor blade surface 30. In other words, the flow of water droplets attached to the rotor blade hydrophilic portion 3A extending linearly toward the casing opening 17 can be stably guided toward the casing opening 17. Therefore, the influence of the flow field of the rotor blade surface 30, which changes depending on the operating conditions of the steam turbine 1, is reduced, and the liquid droplets and liquid film on the rotor blade hydrophilic portion 3A can be stably flowed into the casing opening 17.

[0036] In this manner, by using multiple stator vane hydrophilic portions 4A and multiple rotor blade hydrophilic portions 3A arranged at a distance from each other in the radial direction Dr, water droplets can be efficiently guided to openings for discharging water droplets, such as the drain inlet 45 or the casing opening 17, without relying on the flow of steam S in the main flow passage 15.

[0037] Furthermore, among the multiple bucket hydrophilic portions 3A, the inclination with respect to the axis Ar is made larger for the bucket hydrophilic portion 3A disposed at a position closer to the rotor shaft 21, which is the innermost Dri in the radial direction Dr. Therefore, water droplets adhering to the root of the bucket 32, which is the innermost Dri in the radial direction Dr, can also be sent with high accuracy to the casing opening 17 by the bucket hydrophilic portion 3A. This makes it possible to improve the efficiency of collection of water droplets adhering to the bucket surface 30.

[0038] Furthermore, among the multiple stator blade hydrophilic portions 4A, the inclination with respect to the axis Ar is greater for the stator blade hydrophilic portion 4A located closer to the rotor shaft 21, which is the innermost Dri in the radial direction Dr. Therefore, liquid adhering to the base of the stator blade 42, which is the innermost Dri in the radial direction Dr, can also be sent with high accuracy to the drain suction port 45 by the stator blade hydrophilic portion 4A. This improves the efficiency of collection of water droplets adhering to the stator blade surface 40.

[0039] In addition, the stator blade hydrophilic portion 4A extends from the leading edge of the stator blade 42 to the drain suction port 45. Therefore, water droplets adhering to the vicinity of the leading edge of the stator blade 42 can also be stably sent to the drain suction port 45. This improves the efficiency of collection of water droplets adhering to the stator blade surface 40.

[0040] Also, when viewed from the circumferential direction Dc, the inclination of the multiple rotor blade hydrophilic portions 3A with respect to the axis Ar is larger than the inclination of the multiple stator blade hydrophilic portions 4A arranged at the same position in the radial direction Dr with respect to the axis Ar. Therefore, water droplets that open on the inner peripheral surface of the casing 10 facing the tip of the rotor blade 32 and flow on the rotor blade hydrophilic portions 3A can be sent with high accuracy to the casing opening 17 located on the outer side Dro in the radial direction Dr with respect to the rotor blade 32. Therefore, the recovery efficiency of water droplets attached to the rotor blade surface 30 can be improved.

[0041] In addition, the bucket hydrophilic portion 3A extends from the leading edge to the trailing edge of the bucket 32. Therefore, water droplets adhering to the vicinity of the leading edge of the bucket 32 ​​can be stably sent to the trailing edge and splashed to the casing opening 17. This improves the efficiency of collection of water droplets adhering to the bucket surface 30.

[0042] (Other embodiments) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included.

[0043] For example, the configuration of each part of the steam turbine 1, including the number of stages of the rotor blade rows 31 and the stator blade rows 41, can be changed as appropriate. That is, the steam turbine 1 is not limited to a structure having seven stages (seven rotor blade rows 31 and stator blade rows 41) as in this embodiment. Therefore, the steam turbine 1 may have six stages or less as in this embodiment, or eight stages or more.

[0044] Furthermore, the stator vane 42 on which the stator vane hydrophilic portion 4A is formed and the rotor blade 32 on which the rotor blade hydrophilic portion 3A is formed are not limited to being only a part of the multiple stages 50, as in the fifth stage 50E and the sixth stage 50F of this embodiment. The stator vane 42 on which the stator vane hydrophilic portion 4A is formed and the rotor blade 32 on which the rotor blade hydrophilic portion 3A is formed may be formed in all stages 50. Furthermore, even if the stator vane 42 on which the stator vane hydrophilic portion 4A is formed and the rotor blade 32 on which the rotor blade hydrophilic portion 3A is formed are formed in some stages 50, they may be formed in a region including the final stage 50G.

[0045] Furthermore, the number and shapes of the stator blade hydrophilic portion 4A and the rotor blade hydrophilic portion 3A are not limited to those in this embodiment. For example, the stator blade hydrophilic portion 4A and the rotor blade hydrophilic portion 3A are not limited to being linear, and may be formed in a curved shape.

[0046] <Additional Notes> The steam turbine 1 described in the embodiment can be understood, for example, as follows.

[0047] (1) A steam turbine 1 according to a first aspect includes a rotor shaft 21 rotatable about an axis Ar, a plurality of moving blades 32 fixed to the outside of the rotor shaft 21 in a radial direction Dr based on the axis Ar, a casing 10 covering the rotor shaft 21 and the plurality of moving blades 32 from the outside Dro of the radial direction Dr and having a main flow passage 15 formed therein through which steam S can flow, and a plurality of stator vanes 42 fixed to the inside Dri of the casing 10 in the radial direction Dr and arranged on a first side in the axial direction Da with respect to the plurality of moving blades 32, and the casing 10 has a plurality of stages 50 formed by pairs of the moving blades 32 and the stator vanes 42 aligned in the axial direction Da, and the casing 10 has a plurality of stages 50 formed by pairs of the moving blades 32 and the stator vanes 42 aligned in the axial direction Da, and in at least one of the stages 50, on a second side in the axial direction Da with respect to the moving blades 32, The rotor blade 32 has a casing opening 17 that opens on an inner circumferential surface facing the tip of the rotor blade 32 and into which water droplets flowing through the main flow passage 15 can flow, and the rotor blade 32 arranged in at least one of the stages has a plurality of rotor blade hydrophilic portions 3A that are formed at intervals in the radial direction Dr with respect to a rotor blade surface 30 extending in the radial direction Dr and guide the water droplets attached to the rotor blade surface 30 toward the casing opening 17, and the stator blade 42 arranged in at least one of the stages 50 has a drain suction port 45 that opens on a stator blade surface 40 extending in the radial direction Dr and into which the water droplets attached to the stator blade surface 40 can flow, and a plurality of stator blade hydrophilic portions 4A that are formed at intervals in the radial direction Dr with respect to the stator blade surface 40 and guide the water droplets attached to the stator blade surface 40 toward the drain suction port 45.

[0048] In such a steam turbine 1, water droplets attached to the stator blade surface 40 come into contact with the stator blade hydrophilic portion 4A. The water droplets flowing over the stator blade hydrophilic portion 4A flow into the drain inlet 45. At this time, the stator blade hydrophilic portion 4A is formed at intervals in the radial direction Dr with respect to the stator blade surface 40. Therefore, even if the steam S gathers and flows at a position in the radial direction Dr with respect to the stator blade surface 40, the steam S can come into contact with any of the multiple stator blade hydrophilic portions 4A. In addition, by arranging the multiple stator blade hydrophilic portions 4A at intervals in the radial direction Dr, the water droplets attached to the stator blade hydrophilic portion 4A can be guided in an intended direction, compared to a case where a hydrophilic portion is formed to cover a wide area of ​​the stator blade surface 40. In other words, the flow of the water droplets attached to the stator blade hydrophilic portion 4A can be stably guided toward the drain inlet 45. This makes it difficult for the flow field on the stator blade surface 40 to be affected by changes in operating conditions of the steam turbine 1, and allows the liquid droplets and liquid film on the stator blade hydrophilic portion 4A to flow stably into the drain suction port 45.

[0049] Also, the water droplets adhering to the moving blade surface 30 come into contact with the moving blade hydrophilic portion 3A. The water droplets flowing on the moving blade hydrophilic portion 3A are blown away with momentum toward the casing opening 17. Therefore, the water droplets flowing on the moving blade hydrophilic portion 3A flow into the casing opening 17. At this time, the moving blade hydrophilic portion 3A is formed at intervals in the radial direction Dr with respect to the moving blade surface 30. Therefore, even if the steam S is concentrated and flows at a position in the radial direction Dr with respect to the moving blade surface 30, the steam S can come into contact with any of the multiple moving blade hydrophilic portions 3A. Also, by arranging the multiple moving blade hydrophilic portions 3A at intervals in the radial direction Dr, the water droplets adhering to the moving blade hydrophilic portion 3A can be guided in an intended direction compared to the case where the hydrophilic portion is formed to cover a wide area of ​​the moving blade surface 30. In other words, the flow of the water droplets adhering to the moving blade hydrophilic portion 3A can be stably guided toward the casing opening 17. This makes it difficult for the flow field on the rotor blade surface 30 to be affected by changes in the operating conditions of the steam turbine 1 , and allows the liquid droplets and liquid film on the hydrophilic surface of the rotor blade 32 to flow stably into the casing opening 17 .

[0050] In this manner, by using multiple stator vane hydrophilic portions 4A and multiple rotor blade hydrophilic portions 3A arranged at a distance from each other in the radial direction Dr, water droplets can be efficiently guided to openings such as the drain inlet 45 and the casing opening 17 without relying on the flow of steam S in the main flow passage 15.

[0051] (2) A steam turbine 1 according to a second aspect is the steam turbine 1 of (1), wherein the inclination of the multiple moving blade hydrophilic portions 3A with respect to the axis Ar is made larger the closer they are positioned to the rotor shaft 21 in the radial direction Dr.

[0052] As a result, the water droplets adhering to the root of the rotor blade 32, which is the innermost part Dri in the radial direction Dr, can also be sent with high accuracy to the casing opening 17 by the rotor blade hydrophilic portion 3A. Therefore, the recovery efficiency of the water droplets adhering to the rotor blade surface 30 can be improved.

[0053] (3) A steam turbine 1 according to a third aspect is a steam turbine 1 of (1) or (2), in which the inclination of the multiple stator vane hydrophilic portions 4A with respect to the axis Ar is greater the closer they are to the rotor shaft 21 in the radial direction Dr.

[0054] As a result, the water droplets adhering to the root of the stator blade 42, which is the innermost part Dri in the radial direction Dr, can also be sent with high accuracy to the drain suction port 45 by the stator blade hydrophilic portion 4A. Therefore, the efficiency of collecting the water droplets adhering to the stator blade surface 40 can be improved.

[0055] (4) A steam turbine 1 according to a fourth aspect is any one of the steam turbines 1 of (1) to (3), wherein the inclination of the multiple bucket hydrophilic portions 3A with respect to the axis Ar is greater than the inclination of the multiple stator blade hydrophilic portions 4A with respect to the axis Ar.

[0056] This allows the water droplets flowing on the rotor blade hydrophilic portion 3A to be sent with high precision to the casing opening 17 located on the outer side Dro in the radial direction Dr with respect to the rotor blade 32. Therefore, the efficiency of collecting water droplets adhering to the rotor blade surface 30 can be improved.

[0057] (5) A steam turbine 1 according to a fifth aspect is any one of the steam turbines 1 according to (1) to (4), in which the stator blade hydrophilic portion 4A extends from the leading edge of the stator blade 42 to the drain suction port 45.

[0058] As a result, water droplets adhering to the vicinity of the leading edge of the stator blade 42 can also be stably sent to the drain inlet 45. Therefore, the efficiency of collecting water droplets adhering to the stator blade surface 40 can be improved.

[0059] (6) A steam turbine 1 according to a sixth aspect is any one of the steam turbines 1 according to (1) to (5), in which the rotor blade hydrophilic portion 3A extends from the leading edge to the trailing edge of the rotor blade 32.

[0060] As a result, water droplets adhering to the vicinity of the leading edge of the rotor blade 32 can be stably sent to the trailing edge and splashed to the casing opening 17. Therefore, the efficiency of collecting water droplets adhering to the rotor blade surface 30 can be improved. [Explanation of symbols]

[0061] 1. Steam turbine S: Steam Ar…Axis line 20…Rotor 21...Rotor shaft 22...Axis core part 23...Disc section 31...Rotating blade row 32... Moving blade 30…Rotating blade surface 3A…Rotor blade hydrophilic part 10…Casing 11…Nozzle chamber 12...Flow passage chamber 13...Exhaust chamber 15…Main channel 50 steps 51…Exhaust casing 70…Diffuser 17…Casing opening 41…Stator blade row 42…Stationary blade 40…Stationary blade surface 45…Drain suction port 4A…Stator blade hydrophilic part Da…Axial direction Dau…upstream Dad…downstream Dr…Radial direction Dri…inside Dro…Outside Dc…Circumferential direction

Claims

1. A rotor shaft that is rotatable about an axis line; a plurality of rotor blades fixed to an outer side of the rotor shaft in a radial direction based on the axis; a casing that covers the rotor shaft and the plurality of rotor blades from the radial outside and has a main flow passage formed therein through which steam can flow; a plurality of stator vanes fixed to an inner side of the casing in the radial direction and disposed on a first side in the axial direction with respect to the plurality of rotor blades; a plurality of stages each formed by a pair of the rotor blade and the stator blade aligned in the axial direction; the casing has a casing opening portion, which opens at an inner circumferential surface facing a tip of the rotor blade on a second side in the axial direction with respect to the rotor blade in at least one of the stages, and into which water droplets flowing through the main flow passage can flow; the rotor blade arranged in at least one of the stages has a plurality of rotor blade hydrophilic portions formed at intervals in the radial direction with respect to a rotor blade surface extending in the radial direction and configured to guide the water droplets adhering to the rotor blade surface toward the casing opening, The stator vanes arranged in at least one of the stages include a drain suction port that opens on the stator blade surface extending in the radial direction and through which the water droplets adhering to the stator blade surface can flow; a plurality of stator blade hydrophilic portions formed at intervals in the radial direction with respect to the stator blade surface, the hydrophilic portions directing the water droplets adhering to the stator blade surface toward the drain inlet.

2. 2 . The steam turbine according to claim 1 , wherein an inclination of the hydrophilic portions of the rotor blades with respect to the axis increases as the hydrophilic portions are disposed closer to the rotor shaft in the radial direction.

3. 3 . The steam turbine according to claim 1 , wherein an inclination of the plurality of stator vane hydrophilic portions with respect to the axis is greater as the hydrophilic portions are disposed closer to the rotor shaft in the radial direction.

4. 3 . The steam turbine according to claim 1 , wherein an inclination of the hydrophilic portions of the rotor blades with respect to the axis is larger than an inclination of the hydrophilic portions of the stator blades with respect to the axis.

5. The steam turbine according to claim 1 or 2, wherein the stator blade hydrophilic portion extends from a leading edge of the stator blade to the drain inlet.

6. 3. The steam turbine according to claim 1, wherein the hydrophilic portion of the rotor blade extends from a leading edge to a trailing edge of the rotor blade.

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