JP7240303B2 - hydraulic machine runner and hydraulic machine - Google Patents

Description

Embodiments of the present invention relate to hydraulic machine runners and hydraulic machines.

A Francis turbine is known as an example of a hydraulic machine. During operation of the Francis turbine, water flows from the upper reservoir through the penstock into the spiral casing, and the water flowing into the casing flows from the casing through the stay vanes and guide vanes into the runner. The runner is rotationally driven by the water flowing into the runner, and a generator connected to the runner via a main shaft is driven to generate power. The water then exits the runner and is discharged through the draft pipe to a lower pond or tailrace.

By the way, it is generally known that Karman vortices are generated behind an object placed in a flow. Karman vortices can also occur in the runner blade wakes of the hydraulic machinery runners described above. Such Karman vortices can cause vibration of the runner blades and destabilization of the wake of the runner blades. As a result, damage to the runners, shaking of the hydraulic machinery and buildings, etc. may occur. In addition, the Karman vortices may cause a loss of water pressure energy, leading to a decrease in output. Therefore, it is desirable to suppress the occurrence of Karman vortices.

JP 2015-209783 A

An object of the present invention is to provide a hydraulic machine runner and a hydraulic machine that can suppress the generation of Karman vortices.

A runner for a hydraulic machine according to an embodiment includes a crown, a band provided on the outer peripheral side of the crown, and a plurality of runner blades provided between the crown and the band. The runner vane has a first surface, a second surface opposite the first surface, and a first groove extending to the outlet edge of the runner vane on the first surface.

Further, the hydraulic machine according to the embodiment includes the runner of the hydraulic machine described above.

According to the present invention, the occurrence of Karman vortices can be suppressed.

FIG. 1 is a meridional sectional view of the Francis turbine according to the first embodiment. 2 is a partially enlarged sectional view of the runner of FIG. 1; FIG. 3 is a partially enlarged sectional view of the runner blade of FIG. 2. FIG. 4 is a partially enlarged perspective view of the runner blade of FIG. 2; FIG. 5 is a plan view of FIG. 4. FIG. FIG. 6 is a partially enlarged sectional view of runner blades of the runner according to the second embodiment. FIG. 7 is a partially enlarged perspective view of runner blades of the runner according to the second embodiment. 8 is a plan view of FIG. 7. FIG.

Hereinafter, a hydraulic machine runner and a hydraulic machine according to embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
A hydraulic machine runner and a hydraulic machine according to a first embodiment will be described with reference to FIGS. 1 to 5. FIG. Here, first, a Francis turbine, which is an example of a hydraulic machine, will be described with reference to FIG.

As shown in FIG. 1, a Francis turbine 1 includes a spiral casing 2 into which water flows from an upper reservoir through a penstock (both not shown), a plurality of stay vanes 3, and a plurality of guides. It has vanes 4 and a Francis turbine runner 5 (hereinafter simply referred to as runner 5).

The stay vanes 3 are configured to guide the water that has flowed into the casing 2 to the guide vanes 4 and the runners 5, and are arranged at predetermined intervals in the circumferential direction. Channels through which water flows are formed between the stay vanes 3 .

The guide vanes 4 are configured to guide the inflowing water to the runners 5, and are arranged at predetermined intervals in the circumferential direction. Channels through which water flows are formed between the guide vanes 4 . Each guide vane 4 is configured to be rotatable, and by rotating each guide vane 4 to change the degree of opening, the flow rate of water flowing into the runner 5 can be adjusted. In this way, the power generation amount of the generator 7, which will be described later, can be adjusted.

The runner 5 is configured to be rotatable about the rotation axis X with respect to the casing 2, and is rotationally driven by water flowing in from the casing 2 during operation of the water turbine. That is, the runner 5 converts pressure energy of water flowing into the runner 5 into rotational energy.

A generator 7 is connected to the runner 5 via a main shaft 6 . The power generator 7 is configured to generate power by being transmitted with the rotational energy of the runner 5 during operation of the water turbine.

A draft pipe 8 is provided on the downstream side of the runner 5 during turbine operation. The draft pipe 8 is connected to a lower pond or a water discharge channel (not shown) so that the water that rotates the runner 5 recovers its pressure and is discharged to the lower pond or water discharge channel.

The generator 7 may also function as an electric motor, and may be configured to rotate the runner 5 when supplied with electric power. In this case, the water in the lower pond can be sucked up through the draft pipe 8 and discharged into the upper pond, and the Francis turbine 1 can be operated as a pump turbine (pumping operation). At this time, the opening degree of the guide vanes 4 is changed according to the lift of the pump so as to obtain an appropriate amount of pumped water.

Next, the runner 5 according to this embodiment will be described. In addition, below, it demonstrates according to the flow of the water at the time of water turbine operation. The thick arrow in FIG. 2 indicates the flow direction (main stream direction) of water flowing through the runner 5 at the design point during operation of the water turbine.

As shown in FIG. 2, the runner 5 includes a crown 9 connected to the main shaft 6, a band 10 provided on the outer peripheral side of the crown 9, and a plurality of runner blades provided between the crown 9 and the band 10. 11 and . The runner blades 11 are arranged at predetermined intervals in the circumferential direction, and are joined to the crown 9 and the band 10 respectively. Flow paths (inter-blade flow paths) through which water flows are formed between the runner blades 11 .

As shown in FIG. 2, the runner blade 11 has an inlet-side edge 11A arranged on the water inlet side and an outlet-side edge 11B arranged on the water outlet side. Further, as shown in FIG. 3, the runner blade 11 has a pressure surface 11P (second surface) and a negative pressure surface 11N (first surface) provided on the opposite side of the pressure surface 11P. . A camber line CL is defined by the pressure surface 11P and the negative pressure surface 11N. Here, the camber line CL means a line connecting the centers of inscribed circles contacting both the pressure surface 11P and the negative pressure surface 11N.

In the present embodiment, as shown in FIG. 3, the runner blade 11 has a pressure side surface 11PS (second main body surface) and a negative pressure side surface 11NS (first main body surface) provided on the side opposite to the pressure side surface 11PS. ), and a coating layer 13N (first coating layer) provided on the negative pressure side surface 11NS. In this embodiment, the pressure surface 11P is configured by the pressure side surface 11PS of the blade main body 11S. On the other hand, the negative pressure surface 11N is composed of a portion of the negative pressure side surface 11NS of the blade main body 11S where the coating layer 13N is not provided and the surface 13NS of the coating layer 13N.

Further, the runner blade 11 has a groove 12N (first groove), which will be described later, provided on the negative pressure surface 11N. In the present embodiment, groove 12N is formed in coating layer 13N. This will be explained below.

As described above, in the present embodiment, runner blade 11 has coating layer 13N provided on suction side surface 11NS of blade main body 11S. The coating layer 13N is formed in a region near the exit edge 11B of the runner blade 11. As shown in FIG. More specifically, the coating layer 13N is formed in the downstream region of the runner blades 11, has an inlet end 13NA and an outlet end 13NB, and is located between the pressure surface 11P and the suction surface 11N. The outlet end 13NB of the coating layer 13N and the outlet side edge 11B of the runner blade 11 overlap when viewed in a direction perpendicular to the intermediate plane IS (from the upper side in FIG. 3). Here, the intermediate plane IS is a cross section of the runner blade 11 along the mainstream direction, and is formed by a plane connecting camber lines CL of cross sections at arbitrary positions in the radial direction or the rotation axis direction of the runner 5. .

The coating layer 13N is made of paint. The coating layer 13N can be formed by applying paint to the negative pressure side 11NS and curing the paint. As the paint, for example, a paint containing fluororesin or a paint containing silicone resin may be used. As the paint, for example, a hydrolyzable ship bottom paint may be used. The coating layer 13N may be formed so as to become thicker toward the exit edge 11B. Such a coating layer 13N can be obtained, for example, by thinning a region in the vicinity of the outlet-side edge 11B of the suction surface 11N of the existing runner blade 11 by cutting or the like, and forming the coating layer on the suction side surface 11NS shown in FIG. A portion where 13N is not provided may be formed and may be formed in the portion. As described above, the surface 13NS of the coating layer 13N and the portion of the suction side surface 11NS where the coating layer 13N is not provided constitute the suction surface 11N. The surface 13NS of the coating layer 13N and the portion of the negative pressure side 11NS where the coating layer 13N is not provided are smoothly connected.

In the present embodiment, as shown in FIGS. 4 and 5, grooves 12N are formed in coating layer 13N. The groove 12N extends to the exit edge 11B of the runner blade 11. As shown in FIG. The groove 12N opens downstream at the exit edge 11B of the runner blade 11 . In the example shown in FIG. 5, the groove 12N is formed linearly when viewed in a direction perpendicular to the intermediate plane IS, and is formed to extend from the inlet end 13NA of the coating layer 13N to the outlet end 13NB. ing.

As shown in FIG. 5, when viewed in a direction perpendicular to the intermediate plane IS, the groove 12N extends in a direction different from the mainstream direction 14 at the design point at the outlet edge 11B of the runner blade 11. good. In the illustrated example, when viewed in a direction perpendicular to the intermediate plane IS, the groove 12N extends in a direction inclined at an angle θ1 counterclockwise with respect to the mainstream direction 14 at the design point. As a result, when the water flowing through the groove 12N passes through the outlet side edge 11B, the water flow direction 15N is different from the mainstream direction 14 at the design point when viewed in a direction perpendicular to the intermediate plane IS. direction can be turned. The angle θ1 may be, for example, 10 degrees or more and 45 degrees or less. The groove 12N may extend in a direction inclined clockwise with respect to the mainstream direction 14 at the design point.

Moreover, as shown in FIG. 4, the groove 12N may be deepened toward the outlet side edge 11B. In the illustrated example, the depth of groove 12N matches the thickness of coating layer 13N. That is, the suction side surface 11NS is exposed at the bottom of the groove 12N, and the groove 12N has the exposed suction side surface 11NS as the bottom surface and the exposed wall surface of the coating layer 13N as the side wall surface. In this case, since the coating layer 13N is formed so as to become thicker toward the exit-side edge 11B, the groove 12N also becomes deeper toward the exit-side edge 11B. The depth of the groove 12N at the exit edge 11B may be, for example, 0.5 mm or more and 10 mm or less. Note that the depth of the groove 12N may not match the thickness of the coating layer 13N, and may be smaller than the thickness of the coating layer 13N, for example. In this case, the suction side surface 11NS is not exposed at the bottom of the groove 12N, and the groove 12N has the exposed bottom surface of the coating layer 13N as its bottom surface and the exposed wall surface of the coating layer 13N as its sidewall surface.

A plurality of such grooves 12N may be arranged on the negative pressure surface 11N in the direction along the outlet side edge 11B. As shown in FIG. 5, each groove 12N may extend in the same direction so as to be parallel to each other when viewed in a direction perpendicular to the intermediate plane IS. However, without being limited to this, each groove 12N differs from the mainstream direction 14 at the design point at the outlet edge 11B of the runner blade 11 when viewed in a direction perpendicular to the intermediate plane IS. They may extend in different directions as long as they extend in the same direction.

Next, the effect of this embodiment which consists of such a structure is demonstrated.

When the Francis turbine 1 according to the present embodiment is operated, water flows into the guide vanes 4 from the upper reservoir (not shown) through the penstock, the casing 2 and the stay vanes 3, and then flows into the runners 5 from the guide vanes 4. do. The runner 5 is rotationally driven by the water that has flowed into the runner 5 . The rotationally driven runner 5 transmits rotational energy to the generator 7 via the connected main shaft 6, and the generator 7 generates electricity. After that, the water flows from the runner 5, passes through the draft pipe 8, and is discharged to the lower pond (not shown).

The water that has flowed into the runner 5 flows from the inlet side edge 11A toward the outlet side edge 11B on each side of the pressure surface 11P and the negative pressure surface 11N of the runner blades 11 . During this time, the flow of water causes a differential pressure between the pressure surface 11P and the negative pressure surface 11N of the runner blades 11, causing the runner 5 to rotate about the rotation axis X. As shown in FIG.

Here, the water flowing on the pressure surface 11P flows along the pressure side surface 11PS, passes through the outlet-side edge 11B, and flows out downstream of the runner blades 11. As shown in FIG. When the water turbine is operated under the same conditions as the design point, the water flow direction 15P at the outlet side edge 11B of the pressure surface 11P is the same as the mainstream direction 14 at the design point when viewed in a direction perpendicular to the intermediate plane IS. almost coincides with

On the other hand, part of the water flowing on the suction side 11N flows along the suction side 11NS, enters the groove 12N provided in the vicinity of the outlet side edge 11B, and flows along the direction in which the groove 12N extends. flow. After that, the water passes through the outlet edge 11B and flows out downstream of the runner blades 11 . Here, as described above, when viewed in a direction perpendicular to the intermediate plane IS, the groove 12N extends in a direction different from the mainstream direction 14 at the design point at the outlet edge 11B. Therefore, even when the water turbine is operated under the same conditions as the design point, the water flow direction 15N when the water flowing in the groove 12N passes the outlet side edge 11B is the direction perpendicular to the intermediate plane IS. When viewed, it is in a different direction than the mainstream direction 14 at the design point.

In general, when water passes through runner blades 11 , Karman vortices can occur downstream of runner blades 11 . Karman vortices are especially likely to occur when the water flow on the pressure surface 11P side and the water flow on the negative pressure surface 11N side are symmetrical with respect to the camber line CL of the runner blade 11 .

In contrast, according to the present embodiment, the negative pressure surface 11N is provided with the groove 12N extending to the outlet side edge 11B of the runner blade 11. As shown in FIG. As a result, part of the water flowing on the negative pressure surface 11N enters the grooves 12N and flows through the grooves 12N. On the other hand, the pressure surface 11P is not provided with grooves. Therefore, with the camber line CL of the runner blade 11 as a reference, the flow of water on the side of the pressure surface 11P and the flow of water on the side of the negative pressure surface 11N can be made asymmetric. As a result, the generation of Karman vortices can be suppressed.

In particular, according to this embodiment, when viewed in a direction perpendicular to the intermediate plane IS, the groove 12N extends in a direction different from the mainstream direction 14 at the design point at the outlet edge 11B of the runner blade 11. ing. As a result, when the water flowing in the groove 12N passes through the outlet side edge 11B, the water flow direction 15N is different from the mainstream direction 14 at the design point when viewed in a direction perpendicular to the intermediate plane IS. You can turn in different directions. On the other hand, since the pressure surface 11P is not provided with grooves, the water flow direction 15P at the outlet-side edge 11B of the pressure surface 11P, when viewed in a direction perpendicular to the intermediate plane IS, is the mainstream at the design point. It almost coincides with the direction 14. Thereby, the flow direction 15N of water flowing on the negative pressure surface 11N and the flow direction 15P of water flowing on the pressure surface 11P can be made different. Therefore, with the camber line CL of the runner blade 11 as a reference, the flow of water on the side of the pressure surface 11P and the flow of water on the side of the negative pressure surface 11N can be made asymmetric. As a result, the generation of Karman vortices can be effectively suppressed.

Further, according to the present embodiment, the groove 12N is deepened toward the exit edge 11B. As a result, water flowing on the negative pressure surface 11N can be smoothly guided into the grooves 12N and smoothly flow through the grooves 12N. Therefore, loss of pressure energy of water can be suppressed.

Further, according to the present embodiment, a plurality of grooves 12N are provided on the negative pressure surface 11N. As a result, a plurality of grooves 12N can be arranged along the outlet edge 11B, and a wider area in the direction perpendicular to the mainstream direction 14 at the design point can be used for the flow of water on the side of the pressure surface 11P. The flow of water on the side of the pressure surface 11N can be made asymmetrical. Therefore, the generation of Karman vortices can be effectively suppressed.

Further, according to the present embodiment, the groove 12N is formed in the coating layer 13N made of paint, thereby eliminating the need to form the groove 12N directly on the suction side surface 11NS. can be formed, and the formation of the groove 12N can be facilitated. Therefore, an increase in manufacturing cost of the runner 5 can be suppressed.

In the above-described embodiment, an example in which the groove 12N extends in a direction different from the mainstream direction 14 at the design point at the outlet-side edge 11B when viewed in a direction perpendicular to the intermediate plane IS is shown. rice field. However, it is not limited to this, and even if the groove 12N extends in the same direction as the mainstream direction 14 at the design point at the outlet edge 11B when viewed in a direction perpendicular to the intermediate plane IS. good. Even in such a case, part of the water flowing on the negative pressure surface 11N enters the grooves 12N and flows inside the grooves 12N. On the other hand, the pressure surface 11P is not provided with grooves. Therefore, with the camber line CL of the runner blade 11 as a reference, the flow of water on the side of the pressure surface 11P and the flow of water on the side of the negative pressure surface 11N can be made asymmetric. As a result, the generation of Karman vortices can be suppressed.

Further, in the embodiment described above, an example in which the coating layer 13N is provided on the suction side surface 11NS and the grooves 12N are formed in the coating layer 13N is shown. However, the invention is not limited to this, and the groove 12N may be formed directly on the suction side surface 11NS without providing the coating layer 13N on the suction side surface 11NS. For example, the grooves 12N may be formed by cutting the suction surface 11N of the existing runner blade 11 . In this case, it is not necessary to reduce the thickness of the area near the exit edge 11B of the negative pressure surface 11N of the existing runner blade 11 by cutting or the like. Even in such a case, with the camber line CL of the runner blade 11 as a reference, the water flow on the pressure surface 11P side and the water flow on the negative pressure surface 11N side can be made asymmetric. Therefore, the occurrence of Karman vortices can be suppressed.

Further, in the above-described embodiment, the first surface of the runner blade 11 is composed of the suction surface 11N, and the groove 12N is formed in the suction surface 11N. However, the present invention is not limited to this, and the first surface of runner blade 11 may be constituted by pressure surface 11P, and grooves may be formed in pressure surface 11P. In this case, the second surface of the runner blade 11 may be the suction surface 11N, and the groove 12N may not be formed on the suction surface 11N. Even in such a case, with the camber line CL of the runner blade 11 as a reference, the water flow on the pressure surface 11P side and the water flow on the negative pressure surface 11N side can be made asymmetric. Therefore, the occurrence of Karman vortices can be suppressed.

Further, in the above-described embodiment, the negative pressure surface 11N is formed with the grooves 12N, but the pressure surface 11P is not formed with the grooves. However, the present invention is not limited to this, and grooves may be formed on both the pressure surface 11P and the negative pressure surface 11N. In this case, on each side of the pressure surface 11P and the suction surface 11N, some of the water enters and flows through the grooves. As a result, the flow of water on the pressure surface 11P side and the flow of water on the negative pressure surface 11N side are complicated by the respective grooves. Therefore, with the camber line CL of the runner blade 11 as a reference, the flow of water on the side of the pressure surface 11P and the flow of water on the side of the negative pressure surface 11N can be made asymmetric. As a result, the generation of Karman vortices can be suppressed.

In this case, the grooves provided on the pressure surface 11P and the grooves provided on the negative pressure surface 11N may extend in the same direction when viewed in a direction perpendicular to the intermediate surface IS. Furthermore, in this case, the grooves provided on the pressure surface 11P and the grooves provided on the negative pressure surface 11N may be arranged at different positions when viewed in a direction perpendicular to the intermediate surface IS. That is, when viewed in a direction perpendicular to the intermediate surface IS, the grooves provided on the pressure surface 11P and the grooves provided on the negative pressure surface 11N are arranged so as not to overlap or only partially overlap. may have been In this case, the flow of water on the side of the pressure surface 11P and the flow of water on the side of the negative pressure surface 11N can be made more asymmetric with respect to the camber line CL. As a result, the generation of Karman vortices can be effectively suppressed.

(Second embodiment)
Next, a hydraulic machine runner and a hydraulic machine according to a second embodiment will be described with reference to FIGS. 6 to 8. FIG.

In a second embodiment shown in FIGS. 6 to 8, the runner vanes have a second groove on the second surface extending to the outlet edge and viewed in a direction perpendicular to the intermediate surface. The main difference is that the first grooves and the second grooves extend in different directions when the groove is closed, and other configurations are substantially the same as those of the first embodiment shown in FIGS. is. 6 to 8, the same parts as in the first embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the present embodiment, runner blade 11 has groove 12P (second groove) provided on pressure surface 11P (second surface). The groove 12P is formed in a coating layer 13P (second coating layer), which will be described later.

In the present embodiment, as shown in FIG. 6, runner blade 11 has coating layer 13P provided on pressure side surface 11PS (second main body surface). The coating layer 13P is formed in a region near the exit edge 11B of the runner blade 11. As shown in FIG. More specifically, the coating layer 13P is formed in a region downstream of the runner blades 11, has an inlet end 13PA and an outlet end 13PB, and is coated when viewed in a direction perpendicular to the intermediate plane IS. The outlet end 13PB of the layer 13P and the outlet side edge 11B of the runner blade 11 are overlapped. The coating layer 13P may be provided at a position corresponding to the coating layer 13N provided on the negative pressure side 11NS. That is, the coating layer 13P may be provided at a position overlapping the coating layer 13N provided on the suction side surface 11NS when viewed in a direction perpendicular to the intermediate surface IS. However, the present invention is not limited to this, and the coating layer 13P may not partially overlap the coating layer 13N provided on the suction side surface 11NS. For example, the inlet end 13PA of the coating layer 13P may be located upstream or downstream of the inlet end 13NA of the coating layer 13N provided on the negative pressure side 11NS.

The coating layer 13P is made of paint. The coating layer 13P can be formed by applying paint to the pressure side 11PS and curing it. As the paint, the same material as the coating layer 13N provided on the negative pressure side 11NS may be used. The coating layer 13P may be formed so as to become thicker toward the exit edge 11B. Such a coating layer 13P is obtained, for example, by thinning a region near the exit side edge 11B of the pressure surface 11P of the existing runner blade 11 by cutting or the like, and forming the coating layer 13P on the pressure side surface 11PS shown in FIG. may be formed in a portion where the is not provided. The surface 13PS of the coating layer 13P and the portion of the pressure side surface 11PS where the coating layer 13P is not provided constitute the pressure surface 11P. The surface 13PS of the coating layer 13P and the portion of the pressure side 11PS where the coating layer 13P is not provided are smoothly connected.

In the present embodiment, as shown in FIGS. 7 and 8, grooves 12P are formed in coating layer 13P. The groove 12P extends to the exit edge 11B of the runner blade 11. As shown in FIG. The groove 12P opens downstream at the exit edge 11B of the runner blade 11 . In the example shown in FIG. 8, the groove 12P is formed linearly when viewed in a direction perpendicular to the intermediate plane IS, and is formed to extend from the inlet end 13PA of the coating layer 13P to the outlet end 13PB. ing.

As shown in FIG. 8, even if the grooves 12N provided on the suction surface 11N and the grooves 12P provided on the pressure surface 11P extend in mutually different directions when viewed in a direction perpendicular to the intermediate surface IS. good. In the illustrated example, when viewed in a direction perpendicular to the intermediate surface IS, the grooves 12P provided on the pressure surface 11P are located on the opposite side of the direction in which the grooves 12N provided on the suction surface 11N extend, i.e. It extends in a direction inclined at an angle θ2 clockwise with respect to the mainstream direction 14 at the design point. As a result, when viewed in a direction perpendicular to the intermediate surface IS, the flow direction 15N of water flowing through the grooves 12N provided in the negative pressure surface 11N and the pressure surface 11P when the water passes through the outlet side edge 11B. The direction 15P of water flowing through the groove 12P provided in the outlet side can be made different from the water flow direction 15P when the water passes through the outlet side edge 11B. The angle θ2 may be, for example, 10 degrees or more and 45 degrees or less, or may be equal to the angle θ1. When the groove 12N provided on the negative pressure surface 11N extends in a direction inclined clockwise with respect to the mainstream direction 14 at the design point, the groove 12P provided on the pressure surface 11P extends in the mainstream direction at the design point. 14 may be tilted counterclockwise.

Also, the groove 12P may be deepened toward the outlet side edge 11B, similarly to the groove 12N. Similarly, the depth of groove 12P may match the thickness of coating layer 13P. In this case, since the coating layer 13P is formed so as to become thicker toward the exit-side edge 11B, the groove 12P also becomes deeper toward the exit-side edge 11B. The depth of the groove 12P at the exit edge 11B may be approximately the same as the depth of the groove 12N. Note that the depth of the groove 12P may not match the thickness of the coating layer 13P, and may be smaller than the thickness of the coating layer 13P, for example.

A plurality of such grooves 12P may be arranged on the pressure surface 11P in the direction along the outlet side edge 11B. As shown in FIG. 8, each groove 12P may extend in the same direction so as to be parallel to each other when viewed in a direction perpendicular to the intermediate plane IS. However, the present invention is not limited to this, and each groove 12P may extend in a direction different from the direction in which the grooves 12N provided in the suction surface 11N extend when viewed in a direction perpendicular to the intermediate surface IS. For example, they may extend in different directions.

After flowing along the pressure side 11PS, part of the water flowing on the pressure side 11P enters the grooves 12P provided in the vicinity of the outlet edge 11B and flows along the extending direction of the grooves 12P. After that, the water passes through the outlet edge 11B and flows out downstream of the runner blade 11 along the direction in which the groove 12P extends.

On the other hand, part of the water flowing on the suction side 11N flows along the suction side 11NS, enters the groove 12N provided in the vicinity of the outlet side edge 11B, and flows along the direction in which the groove 12N extends. flow. After that, the water passes through the outlet edge 11B and flows out downstream of the runner blade 11 along the direction in which the groove 12N extends.

Here, as described above, the grooves 12N provided on the suction surface 11N and the grooves 12P provided on the pressure surface 11P extend in mutually different directions when viewed in a direction perpendicular to the intermediate surface IS. . Therefore, when viewed in a direction perpendicular to the intermediate surface IS, the flow direction 15N of water flowing through the grooves 12N provided on the negative pressure surface 11N and the pressure surface 11P when the water passes through the outlet side edge 11B. It is different from the water flow direction 15P when the water flowing through the groove 12P provided in the outlet side edge 11B passes through.

As described above, according to the present embodiment, the pressure surface 11P is provided with the groove 12P extending to the outlet side edge 11B of the runner blade 11, and when viewed in a direction perpendicular to the intermediate plane IS, the groove 12N and the groove 12P extend in different directions. As a result, when viewed in a direction perpendicular to the intermediate surface IS, the flow direction 15N of water flowing on the negative pressure surface 11N can be made different from the flow direction 15P of water flowing on the pressure surface 11P. Therefore, with the camber line CL of the runner blade 11 as a reference, the flow of water on the side of the pressure surface 11P and the flow of water on the side of the negative pressure surface 11N can be made asymmetric. As a result, the generation of Karman vortices can be effectively suppressed.

Further, according to the present embodiment, the groove 12P becomes deeper toward the outlet side edge 11B. As a result, the water flowing on the pressure surface 11P can be smoothly guided into the grooves 12P and smoothly flow through the grooves 12P. Therefore, loss of pressure energy of water can be suppressed.

Further, according to the present embodiment, the plurality of grooves 12P are provided on the pressure surface 11P. As a result, a plurality of grooves 12P can be arranged along the outlet edge 11B, and a wider area in the direction perpendicular to the mainstream direction 14 at the design point can be applied to the water flow on the side of the pressure surface 11P. The flow of water on the side of the pressure surface 11N can be made asymmetrical. Therefore, the generation of Karman vortices can be suppressed more effectively.

Further, according to the present embodiment, the grooves 12P are formed in the coating layer 13P made of paint, which eliminates the need to form the grooves 12P directly on the pressure side surface 11PS. It is possible to facilitate the formation of the groove 12P. Therefore, an increase in manufacturing cost of the runner 5 can be suppressed.

In addition, in the embodiment described above, an example in which the coating layer 13P is provided on the pressure side surface 11PS and the grooves 12P are formed in the coating layer 13P is shown. However, without being limited to this, the pressure side surface 11PS may not be provided with the coating layer 13P, and the grooves 12P may be formed directly on the pressure side surface 11PS. For example, the groove 12P may be formed by cutting the pressure surface 11P of the existing runner blade 11 . In this case, it is not necessary to thin the area in the vicinity of the outlet side edge 11B of the pressure surface 11P of the existing runner blade 11 by cutting or the like. Even in such a case, with the camber line CL of the runner blade 11 as a reference, the water flow on the pressure surface 11P side and the water flow on the negative pressure surface 11N side can be made asymmetric. Therefore, the occurrence of Karman vortices can be suppressed.

Moreover, in the embodiment described above, an example in which the coating layer 13P is provided on both the pressure side surface 11PS and the negative pressure side surface 11NS has been shown. However, the present invention is not limited to this, and one of the suction side 11NS and the pressure side 11PS may be provided with a coating layer and the other side may not be provided with a coating layer. That is, for example, the suction side surface 11NS is provided with the coating layer 13N, and the coating layer 13N is provided with the grooves 12N. may be formed. Alternatively, the coating layer 13P is provided on the pressure side 11PS and the grooves 12P are formed in the coating layer 13P, but the coating layer 13N is not provided on the suction side 11NS, and the grooves 12N are formed directly on the suction side 11NS. may be formed. Even in such a case, with the camber line CL of the runner blade 11 as a reference, the water flow on the pressure surface 11P side and the water flow on the negative pressure surface 11N side can be made asymmetric. Therefore, the occurrence of Karman vortices can be suppressed.

According to the embodiment described above, it is possible to suppress the occurrence of Karman vortices.

Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

In each of the above-described embodiments, the Francis turbine has been described as an example of a hydraulic machine, but the present invention is not limited to this and can be applied to hydraulic machines other than the Francis turbine. . In addition, it can of course be applied to a reaction water turbine that does not operate a pump.

1: Francis turbine, 5: runner, 9: crown, 10: band, 11: runner blade, 11B: outlet side edge, 11N: suction surface, 11NS: suction side, 11P: pressure surface, 11PS: pressure side, 12N, 12P: groove, 13N, 13P: coating layer, 14: mainstream direction at design point, IS: intermediate surface

Claims (10)

a crown;
a band provided on the outer peripheral side of the crown;
a plurality of runner blades provided between the crown and the band;
The runner blade has a first surface, a second surface provided on the opposite side of the first surface, and a first groove extending to an outlet-side edge of the runner blade provided on the first surface. and a second groove in the second surface extending to the outlet edge,
Hydraulic machine, wherein the first groove and the second groove extend in different directions when viewed in a direction perpendicular to an intermediate plane between the first surface and the second surface. runner. When viewed in a direction perpendicular to an intermediate plane between the first and second surfaces, the first groove extends in a direction different from the mainstream direction at a design point at the outlet edge. 2. A runner of a hydraulic machine according to claim 1, wherein the runner is 3. A runner for a hydraulic machine according to claim 1 or 2, wherein said first groove is deepened toward said outlet edge. 4. The runner for a hydraulic machine according to claim 1, wherein said first surface is provided with a plurality of said first grooves. The runner blade is formed of a blade body having a first body surface and a second body surface provided on the opposite side of the first body surface, and a paint provided on the first body surface. a first coating layer;
5. The hydraulic machine runner according to any one of claims 1 to 4, wherein said first groove is formed in said first coating layer. 6. A runner for a hydraulic machine according to any one of claims 1 to 5 , wherein said second grooves are deepened toward said outlet edge. The runner for a hydraulic machine according to any one of claims 1 to 6 , wherein the second surface is provided with a plurality of the second grooves. The runner blade is formed of a blade body having a first body surface and a second body surface provided on the opposite side of the first body surface, and a paint provided on the second body surface. a second coating layer;
8. The hydraulic machine runner according to any one of claims 1 to 7 , wherein said second groove is formed in said second coating layer. The runner blade further includes a first coating layer formed of paint and provided on the first body surface,
9. The hydraulic machine runner according to claim 8 , wherein said first groove is formed in said first coating layer. A hydraulic machine comprising a hydraulic machine runner according to any one of claims 1 to 9 .

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