Patent ID: 12221900

DESCRIPTION OF EMBODIMENTS

First Embodiment

(Configuration of Steam Turbine)

Hereinafter, a steam turbine1(particularly, a low-pressure steam turbine) and a stator blade10(a turbine stator blade) according to a first embodiment of the present disclosure will be described with reference toFIGS.1and2. As shown inFIG.1, the steam turbine1includes a rotor2and a casing3.

The rotor2has a rotating shaft6having a circular cross section extending along an axis Ac, and a plurality of rotor blade rows7provided on an outer peripheral surface of the rotating shaft6. The rotating shaft6is rotatable around the axis Ac. The plurality of rotor blade rows7are arranged at intervals in an axis Ac direction. Each rotor blade row7has a plurality of rotor blades8arranged in a circumferential direction of the axis Ac. The rotor blade8extends radially outward from the outer peripheral surface of the rotating shaft6. A detailed configuration of the rotor blade8will be described later.

The casing3has a casing body3H that covers the rotor2from an outer peripheral side, and a plurality of stator blade rows9supported from the outer peripheral side and an inner peripheral side by an outer ring21(described later) and an inner ring23(described later) provided on an inner peripheral side of the casing body3H. The casing body3H has a tubular shape centered on the axis Ac. The plurality of stator blade rows9are arranged at intervals in the axis Ac direction. The steam turbine1includes the came number of rotor blade rows7as the stator blade rows9, and one rotor blade row7is located between a pair of the stator blade rows9adjacent to each other in the axis Ac direction. That is, the rotor blade rows7and the stator blade rows9are alternately arranged in the axis Ac direction. One stator blade row9and one rotor blade row7form one “stage”. Each stator blade row9has a plurality of stator blades10arranged, in the circumferential direction of the axis Ac. The stator blade10extends in a radial direction with respect to the axis Ac.

A steam flow path11for taking high-temperature and high-pressure steam guided from an inlet pipe into the stage of the casing body3H is formed on one side of the casing body3H in the axis Ac direction. An exhaust hood12responsible for collecting a pressure of the steam is provided on the other side of the casing body3H in the axis Ac direction.

The steam that has flowed into the steam flow path11flows through the stages in the casing body3H, then passes through the exhaust hood12, and is sent to a condenser (not shown). In the following description, a side on which the steam flow path11is located as viewed from the exhaust hood12will be referred to as an upstream side in a flow direction of the steam. A side on which the exhaust hood12is located as viewed from the steam flow path11is referred to as a downstream side.

(Configuration of Rotor Blade)

As shown inFIG.2, the rotor blade8includes a platform81, a rotor blade body82, and a shroud83. The platform81is installed on the outer peripheral surface of the rotating shaft6(rotating shaft outer peripheral surface6A). The rotor blade body82is provided on an outer peripheral side of the platform81. The rotor blade body82extends in the radial direction and has a blade-shaped cross-sectional shape when viewed in the radial direction. As an example, the rotor blade body82is formed so that a dimension in the axis Ac direction gradually decreases from an inner side to an outer side in the radial direction. The shroud83is provided at an end portion on a radially outer side of the rotor blade body82. The shroud83has a substantially rectangular cross-sectional shape having the axis Ac direction as a longitudinal direction. An outer peripheral surface of the shroud83faces an inner peripheral surface (casing inner peripheral surface3A) of the casing body3H at an interval in the radial direction,

(Configuration of Stator Blade)

The stator blade10has the outer ring21, a stator blade body22, and the inner ring23. In addition, the stator blade body22has a water-repellent region30, a hydrophilic region40, and a slit S. The outer ring21has an annular shape centered on the axis Ac. The outer ring21is supported by the casing body3H via a support member (not shown). The stator blade body22is fixed between the outer ring21and the inner ring23. The stator blade body22extends radially inward from an outer ring inner peripheral surface21A and has a blade-shaped cross-sectional shape when viewed in the radial direction. That is, the stator blade body22extends in a direction intersecting the flow direction of the steam. As an example, a dimension of the stator blade body22in the axis Ac direction gradually decreases from the outer side to the inner side in the radial direction. The inner ring23is provided at an end portion on a radially inner side of the stator blades body22. The inner ring23has a substantially rectangular cross-sectional shape having the axis Ac direction as a longitudinal direction. An inner peripheral surface of the inner ring23faces the rotating shaft outer peripheral surface6A at an interval in the radial direction.

The water-repellent region30, the hydrophilic region40, and the silt S are formed on a surface of the stator blade body22(more specifically, a surface facing the upstream side of both surfaces of the stator blade body22in a thickness direction: a pressure side). As an example, it is desirable that the water-repellent region30is formed from an outer periphery-side end portion of the stator blade body22to a region of about ½ to ⅔ in the radial direction. The water-repellent region30is formed over an entire region from an upstream-side end edge (leading edge Le) to a downstream-side end edge (trailing edge Te) of the stator blade body22.

The water-repellent, region30has higher water repellency than the hydrophilic region40(described later) on the surface of the stator blade body22. For example, the wafer-repellent region30is formed by subjecting the surface of the stator blade body22to fine processing for improving water repellency or by attaching a water-repellent sheet to the surface. When the water-repellent region30is formed in this way, a contact angle of an adhered droplet can be 90° or more. It is sufficient that, the water-repellent region30at least has a difference in hydrophilicity from the hydrophilic region40. For this reason, it is also possible to adopt a configuration in which only the hydrophilic region40is formed on the surface of the stator blade body22and the water-repellent region30is not formed.

On a trailing edge Te side of the water-repellent region30, the slit S is formed as a collecting portion C for collecting a liquid film that has flowed along the hydrophilic region40, which will be described later. The slit S extends along the trailing edge Te. The slit3is one or more elongated holes communicating with an inside of the stator blade body22. That is, the stator blade body22is hollow. It Is desirable that an internal space of the stator blade body22is brought into a negative pressure state by a device (not shown).

A plurality of (for example, four) the hydrophilic regions40are formed in a portion of the stator blade body22from the leading edge Le to the slit S. The hydrophilic region40has relatively high hydrophilicity compared to the above-mentioned water-repellent region30and to regions other than the water-repellent region30. That is, in the hydrophilic region, the contact angle of the adhered droplet is smaller than a contact angle of a droplet adhering to the water-repellent region. Accordingly, the droplet a spread to fit into the surface of the hydrophilic region40and are held in a thin liquid film state.

In the present embodiment, the plurality of hydrophilic regions40are arranged in the radial direction. In addition, a width (that is, radial dimension) of each of the hydrophilic regions40gradually increases from the upstream side (leading edge Le side) toward the downstream side (slit S side). In the example ofFIG.2, an expansion ratio of the width of the hydrophilic region40is constant. That is, the figure shows an example in which both a radially outer end edge and a radially inner end edge of the hydrophilic region40extend linearly. However, it is also possible to adopt a configuration in which the expansion ratio of the width of the hydrophilic region40gradually increases or decreases toward the downstream side, depending on design and specifications.

At an upstream-side end edge of the slit S, the plurality of hydrophilic regions40are continuous. In other wards, the upstream-side end edge of the slit S is connected to the hydrophilic regions40over the entire region. In other words, the upstream-side end edge of the silt S does not come into contact with the water-repellent region30.

(Actions and Effects)

Subsequently, an operation of the steam turbine1and a behavior of the droplets on the stator blade10according to the present embodiment will be described. In operating the steam turbine1, first, high-temperature and high-pressure steam is introduced into an inside of the casing body3H through the steam flow path11. The steam alternately passes through the above-described stator blade rows and rotor blade rows7while flowing toward the downstream side inside the casing body3H. The stator blade row9rectifies the flow of the steam to cause the steam to flow into the adjacent rotor blade row7on the downstream side. By the steam acting on the rotor blade row7, torque is applied to the rotating shaft6through the rotor blade row7. Due to this torque, the rotor2rotates around the axis Ac. Rotational energy of the rotor2is taken out from a shaft end and is used for driving a generator (not shown) or the like.

Here, energy of the steam parsing through the stage in a main flow path of the turbine is converted into rotational energy each time the steam passes through the stage from the upstream side toward the downstream side, resulting in a decrease in temperature (and pressure). Therefore, in the stator blade row9on the most downstream side, a portion of the steam is liquefied and exists in an air flow as fine droplets, and a portion of the droplets adheres to the surface of the stator blade10(the stator blade body22). These droplets grow to form a liquid film. Furthermore, when the liquid film flows downstream and increases in thickness as the number of droplets continues to increase, a portion of the liquid film is torn off by the steam flow, or the liquid film that remains adhering to the stator blade row9scatters as coarse droplets from the trailing edge of the stator blade. The scattering droplets flow toward the downstream side while gradually accelerating due to the steam flow. When the coarse droplets collide with the rotor blade8on the downstream side, erosion may occur on a surface of the rotor blade8. In addition, the collision of the droplets may hinder rotation of the rotor blade8(rotor2), resulting in braking loss.

Therefore, in the present embodiment, the hydrophilic region40is formed on the surface of the stator blade body22as described above. The droplets adhering to the stator blade body22spread thinly to fit into the hydrophilic region40and form, a liquid film. Since there is a difference in hydrophilicity at a boundary between the hydrophilic region40and another portion, the liquid film is held inside the hydrophilic region40. This liquid film rides on the flow of the steam and flows toward the downstream side in the hydrophilic region40.

Here, the radial dimension of the hydrophilic region40gradually increases toward the downstream side. Therefore, an area of the liquid film expands in the hydrophilic region40as the liquid film flows toward the downstream side, and the liquid film becomes thinner. Accordingly, a surface of the liquid film becomes more stable than in a case where the liquid film is maintained thick. Therefore, waves are less likely to be generated on the surface of the liquid film, and a probability that the liquid film is torn off by the steam flow is reduced. As a result, the liquid film flows toward the downstream side along the hydrophilic region40, and is easily collected by the slit S serving as the collecting portion C. Accordingly, the generation of the coarse droplets that are torn off by the steam flow on an upstream side of the slit S and the coarse droplets that jump over the slit S and that scatter from the trailing edge of the stator blade body22can be Suppressed. Therefore, a probability that the droplets scatter toward the rotor blade8located on the downstream side of the stator blade10can be reduced. On the other hand, in a case where the liquid film is torn off by the steam because the liquid film is thick, the liquid film scatters toward the downstream side as coarse droplets, or the liquid film remaining adhering to the stator blade row9scatters from the trailing edge of the stator blade as coarse droplets and collides with the rotor blade8, so that there is a concern that erosion may occur. According to the above configuration, the occurrence of such erosion can be suppressed.

Furthermore, according to the above configuration, the plurality of hydrophilic regions40are arranged in plurality in the radial direction. Accordingly, the droplets can be guided to the hydrophilic region40in a wider range in the radial direction. In addition, since the steam turbine1is generally continuously operated under rated conditions, a region and a path where a liquid film is formed on the surface of the stator blade body22are substantially constant, and the liquid film tends to be formed on a side closer to the outer side than the inner side in the radial direction (from the outer periphery-side end portion of the stator blade body22to the region of about ½ to ⅔ in the radial direction). For example, when such a region or a path is specified in advance and then the plurality of hydrophilic regions40are formed along the path, an area of the hydrophilic regions40can be minimized. That is, although the water repellency of the surface on an inner peripheral side of the stator blade body22may be higher than that of the water-repellent region30, this causes excessive processing costs. Therefore, it is desirable that the water-repellent region30is formed only on the outer peripheral side on which the hydrophilic regions40are formed as described above. As described above, a manufacturing cost and a maintenance cost can be reduced compared to a case where the hydrophilic region40is formed in the entire stator blade body22.

In addition, according to the above configuration, the hydrophilic region40extends from the leading edge Le of the stator blade body22to the slit3serving as the collecting portion C. Accordingly, the liquid film can be stably guided by the hydrophilic region40over the entire region from the leading edge Le of the stator blade body22to the collecting portion C, and the liquid film can be collected.

In addition, according to the above configuration, the slit8serving as the collecting portion C is formed on the trailing edge Te side of the stator blade body22. The slit S makes it possible to more stably capture and collect the liquid film.

Furthermore, according to the above configuration, at the upstream-side end edge of the slit S, the plurality of hydrophilic regions40are continuous. In other words, the end edge is connected to the hydrophilic regions40over the entire region. Accordingly, for example, compared to a case where a portion of the end edge is not connected to the hydrophilic region40, the amount of the liquid film that can be guided to the collecting portion C can be increased, and the liquid film can be more efficiently and stably captured and collected.

Moreover, according to the above configuration, a portion extending in the radial direction to the hydrophilic region40is defined as the water-repellent region30. Accordingly, a difference in hydrophilicity at a boundary between the hydrophilic region40and the water-repellent region30can be further increased. As a result, a probability that the liquid film adhering to the hydrophilic region40moves to the water-repellent region30side over the boundary can be reduced. That is, the liquid film is easily held inside the hydrophilic region40. As a result, a probability that the liquid film deviates from the hydrophilic region40is further reduced, and the liquid film can be more smoothly guided to the slit3serving as the collecting portion C.

Hereinabove, the first embodiment of the present disclosure has been described. In addition, various changes and modifications of the above-described configuration can be made without departing from the gist of the present disclosure. For example, in the first embodiment, the configuration in which the plurality of (four) hydrophilic regions40are arranged in the radial direction has been described. However, the configuration of the hydrophilic region40is not limited thereto, and it is also possible to adopt a configuration shown inFIG.3as another example. In the example of the figure, only one hydrophilic region40bis formed from the leading edge Le to the slit3. In addition, a width (radial dimension) of the hydrophilic region40balso gradually increases from the upstream side to the downstream side. Even with such a configuration, it is possible to obtain the same actions and effects as described above.

Second Embodiment

Next, a second embodiment of the present disclosure will be described with reference toFIG.4. Configurations similar to those in the first embodiment and modification examples thereof are assigned the same reference numerals, and detailed description thereof will be omitted. As shown in the figure, in the present embodiment, a separation zone50is formed in each hydrophilic region40.

The separation zone50has water repellency similarly to the water-repellent region30described above. The separation zone50extends in a triangular shape from a position downstream of the leading edge Le side in the hydrophilic region40toward the downstream side. More specifically, a radial dimension of the separation zone50gradually increases from the leading edge Le side toward the slit5side. Accordingly, the hydrophilic region40is partitioned into a plurality of (two) regions in the radial direction, and forms a pair of regions extending in a band shape from the upstream side to the downstream side. The pair of regions extend from the upstream side toward the downstream side so as to be separated from each other on both sides in the radial direction.

According to the above configuration, the separation zone50is formed in the hydrophilic region40. By appropriately adjusting a shape and dimensions of the separation zone50in accordance with the behavior of the liquid film in an actual steam turbine1, a traveling direction of the liquid film in the hydrophilic region40can be more precisely controlled. In other words, since the separation zone50is formed, the width (radial dimension) of the hydrophilic region40becomes relatively small, and a length thereof in an upstream-downstream direction becomes relatively large. Accordingly, when the liquid film is guided from the upstream side to the downstream side, a probability that the flow of the liquid film deviates in the radial direction is reduced, so that it is possible to more stably guide the droplets to the collecting portion C on the downstream side. Accordingly, the probability that the liquid film grows and scatters toward the rotor blade8on the downstream side can be further reduced.

Hereinabove, the second embodiment of the present disclosure has been described. In addition, various changes and modifications of the above-described configuration can be made without departing from the gist of the present disclosure. For example, in the second embodiment, an example in which only one separation zone50is formed in one hydrophilic region40has been described. However, an aspect of the separation zone50is not limited thereto, and as another example, it is possible to form two or more separation zones50in each hydrophilic region40.

Third Embodiment

Subsequently, a third embodiment of the present disclosure will be described with reference toFIG.5. Configurations similar to those in each of the above-described embodiments are assigned the same reference numerals, and detailed description thereof will be omitted. As shown in the figure, in the present embodiment, a shape of a hydrophilic region40cis different front that of each of the above-described embodiments. Furthermore, in the present embodiment, the slit S is not formed in the stator blade body22.

The hydrophilic region40cextends from the leading edge Le of the stator blade body22toward the inner peripheral surface (outer ring inner peripheral surface21A) of the outer ring21. That is, the hydrophilic region40cextends radially outward from the upstream side toward the downstream side. The outer ring inner peripheral surface21A forms a collecting portion C that collects the liquid film that has flowed along the hydrophilic region40c. In the hydrophilic region40c, a width (radial dimension) gradually increases toward the downstream side (the outer ring inner peripheral surface21A side). A plurality (three as an example) of such hydrophilic regions40care formed at intervals in the radial direction.

According to the above configuration, the outer ring inner peripheral surface21A functions as the collecting portion C. That is, the droplets adhering to the stator blade body22form a liquid film in the hydrophilic region40c, and then flow toward the outer peripheral side and flow to the outer ring inner peripheral surface21A. Accordingly, the flow of the liquid film toward the downstream side in the flow direction (main flow direction) of the steam is reduced, and the probability that the droplets scatter toward the rotor blade B on the downstream side can be further reduced. Accordingly, the occurrence of erosion in the rotor blade8can be suppressed.

Hereinabove, the third embodiment of the present disclosure has been described. In addition, various changes and modifications of the above-described configuration can be made without departing from the gist of the present disclosure.

Fourth Embodiment

Next, a fourth embodiment of the present disclosure will be described with reference toFIG.6. Configurations similar to those in each of the above-described embodiments are assigned the came reference numerals, and detailed description thereof will foe omitted. As shown in the figure, in the present embodiment, a hydrophilic region40dhas a first region A1having the same configuration as the hydrophilic region40cdescribed in the third embodiment, and a second region A2formed on an inner peripheral side of the first region A1.

The first region A1extends from the leading edge Le toward the outer ring inner peripheral surface21A. On the other hand, the second region A2extends radially inward from the upstream side toward the downstream side. A plurality of (three as an example) the second regions A2are arranged at intervals in the radial direction. In addition, an upstream-side end portion of the second region A2is located in the middle of the first region A1in an extending direction (a direction including a component in the axis Ac direction). A downstream-side end portion of the second region A2is located at the trailing edge Te.

According to the above configuration, most of the liquid film can be guided toward the outer ring21by the first region A1, and a component of the droplets that cannot be completely captured by the first region A1or a component deviating from the first region A1can be captured by the second region A2. The second region A2extends radially inward toward the downstream side. Accordingly, a probability that the liquid droplet or the liquid film stays in a central portion of the stator blade body22in the radial direction is reduced. Even in a case where the liquid film in the second region A2is torn off and coarse droplets are generated, the coarse droplets can scatter toward an inner periphery-side portion of the rotor blade8on the downstream side. Since an inner peripheral side of the rotor blade8has a lower circumferential speed than that of an outer periphery-side end portion, thereof, a relative speed with respect to the coarse droplets can be minimized. As a result, even in a case where the coarse droplets collide with the inner peripheral side of the rotor blade3, it is possible to minimize the probability of erosion.

Hereinabove, the fourth embodiment of the present disclosure has been described. In addition, various changes and modifications of the above-described configuration can be made without departing from the gist of the present disclosure.

<Additional Notes>

The turbine stator blade (stator blade10) and the strain turbine1described in each embodiment are identified as follows, for example.

(1) The turbine stator blade (stator blade10) according to a first aspect includes: the stator blade body22extending in the radial direction intersecting the flow direction of the steam; the hydrophilic region40,40b,40c, or40dthat is formed on the surface of the stator blade body22, has higher hydrophilicity than other portions, and has a radial dimension gradually increasing toward the downstream side in the flow direction; and the collecting portion C that is provided on a downstream side of the hydrophilic region40,40b,40c, or40dand that collects a liquid film flowing along the hydrophilic region40,40b,40c, or40d.

According to the above configuration, the hydrophilic region40,40b,40c, or40dis formed on the surface of the stator blade body22. Accordingly, the droplets adhering to the stator blade body22spread thinly to fit into the hydrophilic region40,40b,40c, or40d, and form a liquid film, Since there is a difference in hydrophilicity at the boundary between the hydrophilic region40,40b,40c, or40dand another portion, the liquid film is held inside the hydrophilic region40. This liquid film rides on the flow of the stream and flows toward the downstream side in the hydrophilic region40,40b,40c, or40d. Here, the radial dimension of the hydrophilic region40,40b,40c, or40dgradually increases toward the downstream side. Therefore, the area of the liquid film expands in the hydrophilic region40,40b,40c, or40das the liquid, film flows toward the downstream side, and the liquid film becomes thinner. Accordingly, compared to a case where the liquid film is maintained thick, a probability that the liquid film is torn off by the flow of the steam is reduced. As a result, the liquid film cart be efficiently collected by the collecting portion C, and the probability that the droplets scatter toward the turbine rotor blade (rotor blade8) located on the downstream side of the turbine stator blade can be reduced.

(2) In the turbine stator blade according to a second aspect, a plurality of the hydrophilic regions40,40c, or40darranged in the radial direction are included.

According to the above configuration, the plurality of hydrophilic regions40,40c, or40dare arranged in plurality in the redial direction. Accordingly, the droplets can be guided to the hydrophilic region40,40c, or40din a wider range in the radial direction. In addition, since the steam turbine1is generally continuously operated under the rated conditions, a region and a path where a liquid film is formed on the surface of the stator blade body22are substantially constant. For example, when such a region or a path is specified in advance and then the plurality of hydrophilic regions40,40c, or40dare formed along the path, the area of the hydrophilic region40,40c, or40dcan be minimized. Accordingly, the manufacturing cost and the maintenance cost can be reduced compared to the case where the hydrophilic region40,40c, or40dis formed in the entire stator blade body22.

(3) In the turbine stator blade according to a third aspect, the hydrophilic region40,40b, or40c(or the first region A1of the hydrophilic region40d) extends from, the leading edge Le of the stator blade body22to the collecting portion C.

According to the above configuration, the hydrophilic region40,40b, or40c(or the first region A1of the hydrophilic region40d) extends from the leading edge Le of the stator blade body22to the collecting portion C. Accordingly, the liquid film can be stably guided by the hydrophilic region40,40b, or40c(or the first region A1of the hydrophilic region40d) over the entire region from the leading edge Le or the stator blade body22to the collecting portion C, and the liquid film can be more efficiently collected.

(4) The turbine stator blade according to a fourth aspect further includes: the separation zone50that extends from the position downstream of the leading edge Le side in the hydrophilic region40toward the downstream side to partition the hydrophilic region40into a plurality of regions.

According to the above configuration, the separation zone50is formed in the hydrophilic region40. By appropriately adjusting the shape and dimensions of the separation zone50, the traveling direction of the liquid film in the hydrophilic region40can be more precisely controlled. In other words, since the separation zone50is formed, the width (radial dimension) of the hydrophilic region40becomes relatively small, and the length thereof in the upstream-downstream direction becomes relatively large. Accordingly, when the liquid film is guided from the upstream side to the downstream side, the probability that, the liquid film deviates in the radial direction is reduced, so that it is possible to more stably guide the droplets to the collecting portion C on the downstream side.

(5) In the turbine stator blade according to a fifth aspect, the collecting portion C is the slit S that is formed on the trailing edge Te side of the stator blade body22, extends along the trailing edge Te, and communicates with the inside of the stator blade body22.

According to the above configuration, the slit S serving as the collecting portion C is formed on the trailing edge Te side of the stator blade body22. The slit S makes it possible to more stably capture and collect the liquid film.

(6) In the turbine stator blade according to a sixth aspect, a plurality of the hydrophilic regions40arranged in the radial direction are included, and at the upstream-side end edge of the slit S, the plurality of hydrophilic regions40are continuous.

According to the above configuration, at the upstream-side end edge of the slit S, the plurality of hydrophilic regions40are continuous. In other words, the end edge is connected to the hydrophilic regions40over the entire region. Accordingly, for example, compared to a case where a portion of the end edge is not connected to the hydrophilic region40, the amount of the liquid film that does not reach the collecting portion C is reduced, and the liquid film can be more efficiently and stably captured and collected.

(7) The turbine stator blade according to a seventh aspect further includes: the outer ring21provided on the outer peripheral side of the stator blade body22, in which the collecting portion C is the inner peripheral surface (cuter ring inner peripheral surface21A) of the outer ring21.

According to the above configuration, the inner peripheral surface of the outer ring21functions as the collecting portion C. That is, the droplets adhering to the stator blade body22form a liquid film in the hydrophilic region40c(or the first region A1of the hydrophilic region40d), and then flow toward the outer peripheral side and flow to the inner peripheral surface of the outer ring21. Accordingly, the flow of the liquid film toward the downstream side in the flow direction (main flow direction) of the steam is reduced, and the probability that the droplets scatter toward the turbine rotor blade on the downstream side can be further reduced.

(8) In the turbine stator blade according to an eighth aspect, the hydrophilic region40c(or the first region A1of the hydrophilic region40d) extends radially outward from the upstream side toward the downstream side, and is connected to the inner peripheral surface of the outer ring21.

According to the above configuration, the liquid film can be stably and smoothly guided to the inner peripheral surface of the outer ring21along the hydrophilic region40c(or the first region A1of the hydrophilic region40d).

(9) In the turbine stator blade according to a ninth aspect, the hydrophilic region40dhas the first region A1extending toward the inner peripheral surface of the outer ring21, and the second region A2that is formed on the inner peripheral side of the first region A1and that extends radially inward from the upstream side toward the downstream side.

According to the above configuration, most of the liquid film can be guided toward the cuter ring21by the first region A1, and a component of the droplets that cannot be completely captured by the first region A3, caw be captured by the second region A2. The second region A2extends radially inward toward the downstream side. Accordingly, the probability that the liquid film stays in the central portion oil the stator blade body22in the radial direction is reduced. Even in a case where coarse droplets are generated on the trailing edge side due to the liquid film of the second region A2, the coarse droplets can scatter toward the inner periphery-side portion of the turbine rotor blade on the downstream side. Since the inner peripheral side of the turbine rotor blade has a lower circumferential speed than that of the outer periphery-side end portion thereof, a relative speed with respect to the coarse droplets cart be minimized. As a result, even in a case where the coarse droplets collide with the inner peripheral side of the turbine rotor blade, it is possible to minimize the probability of erosion.

In the turbine stator blade according to a tenth aspect, the portion of the surface of the stator blade body22extending to at least the hydrophilic region40,40b,40c, or40dis the water-repellent region30having higher water repellency than the hydrophilic: region40,40b,40c, or40d.

According to the above configuration, the portion extending to the hydrophilic region40,40b,40c, or40dis defined as the water-repellent region30. Accordingly, the difference in hydrophilicity at the boundary between the hydrophilic region40,40b,40c, or40dand the water-repellent region30can be further increased. As a result, the liquid film is easily held inside the hydrophilic region40,40b,40c, or40d, and the probability that the liquid film deviates from the hydrophilic region40,40b,40c, or40dcan be further reduced.

(11) The steam turbine1according to an eleventh aspect includes: the rotating shaft6that is rotatable around the axis Ac; a plurality of turbine rotor blades (rotor blades8) arranged on the outer peripheral surface (rotating shaft outer peripheral surface6A) of the rotating shaft6in the circumferential direction with respect to the axis Ac direction; the casing body3B that covers the rotating shaft6and the turbine rotor blade from the outer peripheral side; and a plurality of the turbine stator blades (stator blades10) which are arranged on the inner peripheral surface of the casing body38in the circumferential direction with respect to the axis Ac and which are provided adjacent to the turbine rotor blades in the axis Ac direction.

According to the above configuration, since the growth of the liquid film is suppressed, it is possible to reduce performance degradation and an erosion phenomenon due to the coarse droplets, and it is possible to provide the steam turbine1with higher efficiency and higher reliability.

INDUSTRIAL APPLICABILITY

The present disclosure relates to a turbine stator blade and a steam turbine. According to the present disclosure, it is possible to provide a turbine stator blade and a steam turbine capable of further reducing growth of a liquid film and facilitating efficient collection of the liquid film.

REFERENCE SIGNS LIST

1: Steam turbine2: Rotor3: Casing3A: Casing inner peripheral surface3H: Casing body6: Rotating shaft6A: Rotating shaft outer peripheral surface7: Rotor blade row8: Rotor blade (turbine sot or: blade)9: Stator blade row10: Stator blade (turbine stator blade)11: Steam flow path12: Exhaust hood21: Outer ring22A: Outer ring inner peripheral surface22: Stator blade body23: Inner ring30: Water-repellent region40,40b,40c,40d: Hydrophilic region50: Separation zone81: Platform82: Rotor blade body83: ShroudA1: First regionA2: Second regionAc: AxisC: Collecting portionLe: Leading edgeS: SlitTe: Trailing edge