JP7085406B2 - Hydraulic machine runner and hydraulic machine - Google Patents

Description

Embodiments of the present invention relate to runners of hydraulic machinery and hydraulic machinery.

In general, the runner of a hydraulic machine is one of the most important mechanical elements that converts the energy of a fluid into power. Therefore, the quality of the runner's performance greatly affects the hydraulic efficiency of the entire hydraulic machine. Therefore, developing a highly efficient runner is an important issue in hydropower design, and many measures for improving hydropower efficiency have been proposed so far.

In a Francis turbine (for example, a Francis turbine having a small specific speed), in general, the larger the number of runner blades, the higher the rectifying effect and the better the hydraulic performance. On the other hand, if the number of runner blades is large, the inter-blade flow path on the outlet side of the runner during operation of the turbine is narrowed, which may impair workability during manufacturing. Therefore, in recent years, a splitter runner has been proposed in which long blades and short blades having a shorter blade length than the long blades are alternately arranged in the circumferential direction of the runner as runner blades. According to this splitter runner, it is possible to improve the hydraulic performance while preventing the workability at the time of manufacturing from being impaired.

However, in the splitter runner as described above, since the short blades are provided as the runner blades, the number of runner blades on the outlet side during operation of the turbine is reduced. Therefore, the wing loading on the runner blades on the outlet side may increase, the pressure on the negative pressure surface may decrease, and the cavitation performance may decrease.

Japanese Unexamined Patent Publication No. 2007-107428

The present invention has been made in consideration of such a point, and an object of the present invention is to provide a runner of a hydraulic machine and a hydraulic machine capable of improving cavitation performance.

The runner of the hydraulic machine according to the 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 plurality of runner blades include a long wing and a short wing whose wingspan is shorter than that of the long wing. Two long wingspans are arranged between a pair of short wingspans adjacent to each other in the circumferential direction.

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

According to the present invention, cavitation performance can be improved.

FIG. 1 is a cross-sectional view of the meridional surface of the Francis turbine according to the first embodiment. FIG. 2 is a conceptual diagram of the runner shown in FIG. 1 as viewed from above. FIG. 3 is a diagram showing the pressure distribution on the blade surface of the runner blade shown in FIG. FIG. 4 is a conceptual diagram of the runner in the second embodiment as viewed from above. FIG. 5 is a conceptual diagram of the runner in the third embodiment as viewed from above. FIG. 6 is a conceptual diagram of the runner in the fourth embodiment as viewed from above. FIG. 7 is a conceptual diagram showing a cross section of the groove welded portion in the fourth embodiment. FIG. 8 is a conceptual diagram showing the vicinity of the exit end when the runner in the fifth embodiment is viewed from the downstream side during operation of the water turbine. FIG. 9 is a conceptual diagram of the runner in the fifth embodiment as viewed from above. FIG. 10 is a conceptual diagram showing the vicinity of the exit end when the runner in the sixth embodiment is viewed from the downstream side during operation of the water turbine.

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

(First Embodiment)
The runner of the hydraulic machine and the hydraulic machine according to the first embodiment will be described with reference to FIGS. 1 to 3. 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, the Francis turbine 1 includes a spiral casing 2 in which water flows from an upper pond through a penstock (none of which is shown) during operation of the turbine, a plurality of stay vanes 3, and a plurality of guides. It has a vane 4 and a runner 5.

The stay vanes 3 are for guiding the water flowing into the casing 2 to the guide vanes 4 and the runner 5, and are arranged at predetermined intervals in the circumferential direction. A flow path through which water flows is formed between the stay vanes 3.

The guide vanes 4 are for guiding the inflowing water to the runner 5, and are arranged at predetermined intervals in the circumferential direction. The guide vane 4 is usually composed of an even number of blades. A flow path through which water flows is formed between the guide vanes 4. Each guide vane 4 is configured to be rotatable, and the flow rate of water flowing into the runner 5 can be adjusted by rotating each guide vane 4 to change the opening degree. In this way, the amount of power generated by 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 the water flowing from the casing 2 during operation of the turbine. That is, the runner 5 is for converting the pressure energy of the water flowing into the runner 5 into rotational energy.

A generator 7 is connected to the runner 5 via a spindle 6. The generator 7 is configured to generate electricity by transmitting the rotational energy of the runner 5 during operation of the water turbine.

A suction pipe 8 is provided on the downstream side of the runner 5 when the water turbine is operated. The suction pipe 8 is connected to a lower pond or a drainage channel (not shown), and the water obtained by rotationally driving the runner 5 recovers the pressure and is discharged to the lower pond or the drainage channel.

The generator 7 also has a function as an electric motor, and may be configured to rotationally drive the runner 5 by supplying electric power. In this case, the water in the lower pond can be sucked up through the suction pipe 8 and discharged to the upper pond, and the Francis turbine 1 can be pumped (pumped) as a pump turbine. At this time, the opening degree of the guide vane 4 is changed so as to have an appropriate pumping amount according to the pump head.

Next, the runner 5 according to the present embodiment will be described.

As shown in FIG. 1, the runner 5 includes a crown 9 connected to a spindle 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 welded to the crown 9 and the band 10, respectively. A flow path (inter-blade flow path) through which water flows is formed between the runner blades 11.

As shown in FIG. 2, the runner blade 11 has an inlet end 11A arranged on the water inlet side during water turbine operation and an outlet end 11B arranged on the water outlet side during water turbine operation. There is. Further, the runner blade 11 has a pressure surface 11P during operation of the water turbine and a negative pressure surface 11N during operation of the water turbine. The 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 the inscribed circles in contact with both the pressure surface 11P and the negative pressure surface 11N. The camber line CL passes through the inlet end 11A and the exit end 11B.

As shown in FIG. 2, in the present embodiment, the plurality of runner blades 11 include long wings 11LA, 11LB and short wings 11SA, 11SB. The wingspan of the short wings 11SA and 11SB is shorter than the wingspan of the long wings 11LA and 11LB. Here, the wingspan means the length of the blade (runner blade 11) from the inlet end 11A to the exit end 11B along the camber line CL.

The inlet ends 11A of the long wings 11LA and 11LB and the inlet ends 11A of the short wings 11SA and 11SB are arranged at the same radial position. In other words, the inlet ends 11A of the long wings 11LA and 11LB and the inlet ends 11A of the short wings 11SA and 11SB have the same radial distance from the rotation center (rotation axis X) of the runner 5. Therefore, the radial positions of the outlet ends 11B of the long wings 11LA and 11LB are arranged radially inside the runner 5 with respect to the radial positions of the exit ends 11B of the short wings 11SA and 11SB. In the form shown in FIG. 2, the long wingspans 11LA and 11LB have the same shape as each other, and the short wingspans 11SA and 11SB also have the same shape as each other.

Two long wingspans 11LA and 11LB are arranged between a pair of short wingspans 11SA and 11SB adjacent to each other in the circumferential direction. In this way, the runner 5 has a configuration in which one short blade 11SA and 11SB and two long wings 11LA and 11LB are alternately arranged side by side in the circumferential direction. In this embodiment, the total number of short wings 11SA and 11SB and long wings 11LA and 11LB is an odd number. More specifically, the runner 5 has three short wingspans and six long wingspans, and has a total of nine runner blades 11.

Next, the operation of the present embodiment having such a configuration will be described.

When the Francis turbine 1 according to the present embodiment is operated, water flows into the guide vane 4 from the upper pond (not shown) through the penstock, the casing 2 and the stay vane 3, and the water flows from the guide vane 4 into the runner 5. do. The runner 5 is rotationally driven by the water flowing into the runner 5. The rotary drive runner 5 transmits rotational energy to the generator 7 via the connected spindle 6, and the generator 7 generates electricity. The water flowing into the runner 5 is discharged from the runner 5 through the suction pipe 8 to a lower pond (not shown).

The water flowing into the runner 5 flows along the runner blade 11 from the inlet side to the outlet side during operation of the turbine. During this time, the pressure on the pressure surface 11P of the runner blade 11 is increased by the flow of water, and the runner 5 is rotated in the rotation direction D shown in FIG.

However, in the splitter runner using the long blade and the short blade as the runner blade 11, the number of runner blades 11 on the outlet side of the runner 5 is smaller than that on the inlet side of the runner 5. For example, in the case of a splitter runner in which long wings and short wings are alternately arranged one by one in the circumferential direction, the number of runner blades 11 on the outlet side of the runner 5 is half the number of runner blades 11 on the inlet side of the runner 5. Decreases to. In this case, a cavitation problem may occur on the exit side of the runner 5.

Here, in general, as the number of runner blades 11 increases, the wing loading applied to each runner blade 11 during operation of the turbine is reduced, and the cavitation performance is improved. This will be described below with reference to FIG.

FIG. 3 shows an example of the pressure distribution of the pressure surface 11P and the negative pressure surface 11N from the inlet end 11A to the outlet end 11B of the runner blade 11. In FIG. 3, the pressure distribution when the number of runner blades 11 is relatively small under the same head condition is shown by a solid line, and the pressure distribution when the number of runner blades 11 is relatively large is shown by a broken line. Further, in FIG. 3, the solid line and the broken line shown above show the pressure distribution of the pressure surface 11P of the runner blade 11, and the solid line and the broken line shown below show the pressure distribution of the negative pressure surface 11N of the runner blade 11. The horizontal axis of FIG. 3 is the distance from the inlet end 11A along the blade surface (pressure surface 11P or negative pressure surface 11N), and indicates the distance from the inlet end 11A when the blade length is 1. Then, the difference between the pressure of the pressure surface 11P and the pressure of the negative pressure surface 11N becomes the blade load (work of the blade) applied to the runner blade 11. The wing loading when the number of runner blades 11 is small is indicated by a solid arrow, and the wing loading when the number of runner blades 11 is large is indicated by a broken line arrow.

As shown by the arrow in FIG. 3, the larger the number of runner blades 11, the smaller the load applied to one runner blade 11, and the higher the pressure on the negative pressure surface 11N. Therefore, when the number of runner blades 11 is large, cavitation on the negative pressure surface 11N is less likely to occur, and the cavitation performance is improved. That is, in order to improve the cavitation performance, it can be said that it is advantageous to have a large number of runner blades 11.

In the runner 5 according to the present embodiment, two long wingspans 11LA and 11LB are arranged between the pair of short wingspans 11SA and 11SB. Therefore, the number of runner blades 11 on the outlet side can be increased as compared with the splitter runner in which the long blades and the short blades are alternately arranged one by one as described above. In the present embodiment, the number of runner blades 11 on the outlet side can be secured to be 2/3 of the number of runner blades 11 on the inlet side. Therefore, the cavitation performance can be improved.

As described above, according to the present embodiment, the two long wings 11LA and 11LB are arranged between the pair of short wings 11SA and 11SB adjacent to each other in the circumferential direction. This makes it possible to increase the number of runner blades 11 on the outlet side. Therefore, it is possible to reduce the wing loading of each runner blade 11 and suppress a decrease in the pressure of the negative pressure surface 11N. As a result, the cavitation performance can be improved.

Further, according to the present embodiment, the total number of short wings 11SA and 11SB and long wings 11LA and 11LB is an odd number. Generally, when the runner blade 11 passes near the guide vane 4, the region between the runner blade 11 and the guide vane 4 becomes high pressure. This high-voltage portion may move in the circumferential direction with the rotation of the runner 5 and generate vibration. The number of high-voltage portions generated at the same time and the magnitude of vibration are determined by the combination of the number of runner blades 11 and the number of guide vanes 4. When the number of runner blades 11 and guide vanes 4 is even, the above-mentioned high-pressure portions may occur at a plurality of locations at substantially the same time, resulting in large vibration. On the other hand, vibration may be suppressed by setting the number of runner blades 11 to an odd number. Specifically, when the number of guide vanes 4 is 20, and the number of runner blades 11 is 10, a high-pressure portion is generated at the same time in all the runner blades 11, and vibration may increase. Here, by setting the number of runner blades 11 to 9 or 11, it is possible to prevent the generation of high-voltage portions in all runner blades 11 at the same time, so that vibration can be suppressed. In particular, when repairing the runner 5 of an existing water turbine, the existing guide vane 4 may be used as it is, so it is effective to change the number of runner blades 11 to take countermeasures. As described above, in the present embodiment, the vibration can be suppressed by setting the number of runner blades 11 to an odd number as described above.

Further, according to the present embodiment, the inlet ends 11A of the long wings 11LA and 11LB and the inlet ends 11A of the short wings 11SA and 11SB are arranged at the same radial positions. As a result, the outlet end 11B of the short blades 11SA and 11SB having a wingspan shorter than that of the long blades 11LA and 11LB can be arranged radially outside the outlet end 11B of the long blades 11LA and 11LB. Therefore, it is possible to secure a space for welding work of the runner blade 11 on the outlet side (inside in the radial direction) where the space is relatively small in the runner 5, and it is possible to improve workability at the time of manufacturing.

Further, according to the present embodiment, in the runner 5, one short wingspan 11SA and 11SB and two long wingspans 11LA and 11LB are alternately arranged side by side in the circumferential direction. As a result, the number of long wings 11LA and 11LB arranged between the pair of short wings 11SA and 11SB adjacent to each other in the circumferential direction can be reduced to two. Therefore, it is possible to prevent a decrease in workability during welding of the long blades 11LA and 11LB. Further, the short wings 11SA and 11SB and the long wings 11LA and 11LB can be regularly arranged in the circumferential direction, and vibration can be suppressed.

(Second embodiment)
Next, the runner of the hydraulic machine and the hydraulic machine according to the second embodiment will be described with reference to FIG.

The second embodiment shown in FIG. 4 is mainly different in that the angle of the outlet end of the first long wing is larger than the angle of the exit end of the second long wing, and the other configurations are different. It is substantially the same as the first embodiment shown in FIGS. 1 to 3. In FIG. 4, the same parts as those of the first embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 4, of the long wingspans 11LA and 11LB arranged between the pair of short wingspans 11SA and 11SB adjacent to each other in the circumferential direction, the long wingspan (first) located on the rotation direction D side during water wheel operation. The angle of the outlet end 11B of the long wing 11LA) is β2A. Further, the angle of the outlet end 11B of the long wing (second long wing 11LB) located on the side opposite to the side in the rotation direction D during operation of the water turbine is β2B. In this embodiment, the angle β2A is larger than the angle β2B. That is, the long wings 11LA and 11LB are arranged so as to satisfy the relational expression of angle β2A> angle β2B. Here, the angle of the exit end 11B means the angle formed by the tangent line T1 and the tangent line T2 shown in FIG. The tangent line T1 is a tangent line at the outlet end 11B of the long wings 11LA and 11LB with respect to the circle R1 passing through the outlet ends 11B of the long wings 11LA and 11LB about the center of rotation of the runner 5. The tangent line T2 is a tangent line at the outlet end 11B with respect to the camber line CL of the long wings 11LA and 11LB.

In this case, on the outlet side of the runner 5, the first long wing 11LA can be moved away from the second long wing 11LB located on the side opposite to the side in the rotation direction D toward the side in the rotation direction D. As a result, the span d1 of the interwing flow path between the first long blade 11LA and the second long blade 11LB arranged between the pair of short blades 11SA and 11SB adjacent to each other in the circumferential direction is widened. Can be done. On the other hand, the span d2 of the interwing channel between the second long wing 11LB and the first long wing 11LA in which one short wing 11SA (or short wing 11SB) is arranged can be narrowed. Therefore, the difference between the width d1 and the width d2 can be reduced.

In the present embodiment, the two long wings 11LA and 11LB arranged between the pair of short wings 11SA and 11SB adjacent to each other in the circumferential direction are from the inlet end 11A of the long wings 11LA and 11LB during the operation of the turbine. It may be formed so as to have the same shape as the outlet end 11B of the short wings 11SA and 11SB up to the same radial position. On the other hand, the long wings 11LA and 11LB may be formed in different shapes from the same radial position as the outlet ends 11B of the short wings 11SA and 11SB to the outlet ends 11B of the long wings 11LA and 11LB.

As described above, according to the present embodiment, the angle β2A of the outlet end 11B of the first long wing 11LA is larger than the angle β2B of the exit end 11B of the second long wing 11LB. As a result, on the outlet side of the runner 5, the width of the interwing channel between the pair of long blades 11LA and 11LB adjacent to each other in the circumferential direction can be made uniform in the circumferential direction. Therefore, the flow rate of water flowing through the inter-blade flow paths on the outlet side of the runner 5 can be made uniform in the circumferential direction. As a result, the hydraulic performance can be further improved.

Further, according to the present embodiment, the two long wings 11LA and 11LB arranged between the pair of short wings 11SA and 11SB adjacent to each other in the circumferential direction are the inlet ends of the long wings 11LA and 11LB during the operation of the turbine. A part including 11A is formed so as to have the same shape as each other. By forming a part of the long wings 11LA and 11LB into the same shape as described above, the production of the runner 5 can be simplified and the production cost can be reduced. In particular, in the present embodiment, they are formed so as to have the same shape from the inlet end 11A of the long wings 11LA and 11LB to the same radial position as the exit end 11B of the short wings 11SA and 11SB. As described above, by making most of the long wings 11LA and 11LB have the same shape, the manufacturing cost can be further reduced.

(Third embodiment)
Next, the runner of the hydraulic machine and the hydraulic machine according to the third embodiment will be described with reference to FIG.

In the third embodiment shown in FIG. 5, the main difference is that the angle of the inlet end of the first long wing is smaller than the angle of the inlet end of the second long wing, and the other configurations are different. It is substantially the same as the first embodiment shown in FIGS. 1 to 3. In FIG. 5, the same parts as those of the first embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 5, of the long wingspans 11LA and 11LB arranged between the pair of short wingspans 11SA and 11SB adjacent to each other in the circumferential direction, the long wingspan (first) located on the rotation direction D side during water wheel operation. The angle of the inlet end 11A of the long wing 11LA) is β1A. Further, the angle of the inlet end 11A of the long wing (second long wing 11LB) located on the side opposite to the side in the rotation direction D during operation of the water turbine is β1B. In this embodiment, the angle β1A is smaller than the angle β1B. That is, the long wings 11LA and 11LB are arranged so as to satisfy the relational expression of the angle β1A <angle β1B. Here, the angle of the inlet end 11A means the angle formed by the tangent line T3 and the tangent line T4 shown in FIG. The tangent line T3 is a tangent line at the inlet end 11A of the long wings 11LA and 11LB with respect to the circle R2 passing through the inlet end 11A of each long wings 11LA and 11LB centered on the rotation center of the runner 5. The tangent line T4 is a tangent line at the inlet end 11A with respect to the camber line CL of the long wings 11LA and 11LB.

In this case, on the inlet side of the runner 5, the first long wing 11LA can be moved away from the second long wing 11LB located on the side opposite to the side in the rotation direction D toward the side in the rotation direction D. As a result, the span d3 of the interwing flow path between the first long blade 11LA and the second long blade 11LB arranged between the pair of short blades 11SA and 11SB adjacent to each other in the circumferential direction is widened. Can be done. On the other hand, the span d4 of the interwing channel between the first long wing 11LA and the short wing 11SA (or the second long wing 11LB and the short wing 11SB) can be narrowed.

As described above, according to the present embodiment, the angle β1A of the inlet end 11A of the first long wing 11LA is smaller than the angle β1B of the inlet end 11C of the second long wing 11LB. As a result, on the inlet side of the runner 5, the span d3 of the interwing channel between the pair of long blades 11LA and 11LB adjacent to each other in the circumferential direction can be widened. Therefore, the flow rate of water flowing through the inter-blade flow paths on the outlet side of the runner 5 can be made uniform in the circumferential direction. That is, since the width d1 of the inter-blade flow path shown in FIG. 4 is smaller than the width d2 of the inter-blade flow path, the flow rate of water flowing through the inter-blade flow path of the width d1 is the inter-blade flow of the width d2. It tends to be less than the flow of water flowing through the road. On the other hand, in the present embodiment, the width d3 on the inlet side of the inter-blade flow path having the width d1 can be expanded, and the width d4 on the inlet side of the inter-blade flow path having the width d2 can be narrowed. As a result, it is possible to increase the flow rate of water flowing into the inter-blade flow path having a width d3 and reduce the flow rate of water flowing into the inter-blade flow path having a width d4. Therefore, the flow rate of water flowing through the inter-blade flow paths on the outlet side of the runner 5 can be made uniform in the circumferential direction. As a result, the hydraulic performance can be further improved.

(Fourth Embodiment)
Next, the runner of the hydraulic machine and the hydraulic machine according to the fourth embodiment will be described with reference to FIGS. 6 and 7.

In the fourth embodiment shown in FIGS. 6 and 7, the groove weld of the long wing is adjacent to the long wing from the outlet end of the long wing to the same radial position as the outlet end of the short wing. The main difference is that it is formed on the side of the wing, and the other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 3. In FIGS. 6 and 7, the same parts as those in the first embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIGS. 6 and 7, the first long wing 11LA located on the side of the rotation direction D during operation of the turbine is attached to the crown 9 and the band 10 via the groove welded portion 12A which is a one-sided groove. It is welded and joined. More specifically, the first long blade 11LA is welded to the stub 9s protruding from the crown 9 and the stub 10s protruding from the band 10 via the groove welded portion 12A. Similarly, the second long wing 11LB located on the side opposite to the side in the rotation direction D during operation of the water turbine has a stub 9s protruding from the crown 9 via a groove welded portion 12B which is a one-sided groove. It is welded to the stub 10s protruding from the band 10. The first long wing 11LA and the second long wing 11LB are welded and joined directly to the crown 9 and the band 10 by the groove welded portions 12A and 12B without using the stubs 9s and 10s as shown in FIG. It may have been done.

In the present embodiment, the groove welded portion 12A is adjacent to the first long blade 11LA from the outlet end 11B of the first long blade 11LA to the same radial position as the outlet end 11B of the short blade 11SA and 11SB. It is formed on the side of the short wing 11SA. That is, the groove welded portion 12A is formed in a one-sided groove shape so as to open at the negative pressure surface 11N of the first long blade 11LA. Further, the groove welded portion 12B is a short blade 11SB adjacent to the second long blade 11LB from the outlet end 11B of the second long blade 11LB to the same radial position as the outlet end 11B of the short blades 11SA and 11SB. It is formed on the side. That is, the groove welded portion 12B is formed in a one-sided groove shape so as to open at the pressure surface 11P of the second long blade 11LB.

In this case, on the outlet side of the runner 5 where the space is relatively small, from the side of the pressure surface 11P of the first long blade 11LA and the side of the negative pressure surface 11N where the space is relatively secured from the side of the negative pressure surface 11N. It can be accessed to form the groove weld 12A. Therefore, a space for welding work can be secured around the groove welded portion 12A. Further, on the outlet side of the runner 5, the groove welded portion is accessed from the side of the pressure surface 11P of the second long blade 11LB and the side of the negative pressure surface 11N where a relatively large space is secured. 12B can be formed. Therefore, a space for welding work can be secured around the groove welded portion 12B.

The portion from the inlet end 11A of the first long blade 11LA to the same radial position as the outlet end 11B of the short blades 11SA and 11SB has a one-sided groove welded structure and a crown 9 as in the groove welded portion 12A described above. And may be welded to the band 10, but groove welds may be formed on both sides of the pressure surface 11P and the negative pressure surface 11N, respectively. The same applies to the second long wing 11LB.

As described above, according to the present embodiment, the groove welded portions 12A and 12B of the long wings 11LA and 11LB are positioned in the same radial direction from the outlet end 11B of the long wings 11LA and 11LB to the outlet ends 11B of the short wings 11SA and 11SB. Up to, it is formed on the side of the short wings 11SA and 11SB adjacent to the long wings 11LA and 11LB. As a result, it is possible to secure a space for welding work of the long blades 11LA and 11LB on the outlet side of the runner 5 where the space is relatively small. Therefore, workability at the time of production can be improved.

(Fifth Embodiment)
Next, the runner of the hydraulic machine and the hydraulic machine according to the fifth embodiment will be described with reference to FIGS. 8 and 9.

In the fifth embodiment shown in FIGS. 8 and 9, when the runner is viewed from the downstream side during water turbine operation, the connection point between the outlet edge line of the long wing and the band is the outlet edge line and the crown. The main difference is that it is located on the rotation direction side of the line passing through the connection point of the runner and the rotation center of the runner, and the other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 3. Is. In FIGS. 8 and 9, the same parts as those in the first embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 8, the two long wingspans 11LA and 11LB arranged between the pair of short wingspans 11SA and 11SB adjacent to each other in the circumferential direction are located on the side opposite to the rotation direction D side during water turbine operation. The outlet edge line 13 of the second long wing 11LB and the band 10 are connected at a connection point 14. Further, the exit edge line 13 and the crown 9 are connected at a connection point 15. In the present embodiment, the second long blade 11LB is formed so that the connection point 14 is located on the rotation direction D side of the line 16 passing through the connection point 15 and the rotation center O of the runner 5. ..

In this case, the wingspan of the second long blade 11LB on the band 10 side portion 11LB-b can be shorter than the blade length on the crown 9 side portion 11LB-c.

When the Francis turbine 1 is pumped as a pump turbine, as shown in FIG. 9, water having a velocity vector W0 (broken line) flows into the runner blade 11 at the design operation point. At this time, since the angle difference between the angle of the outlet end 11B (inlet end during pump operation) during water turbine operation and the water velocity vector W0 is small, the problem of cavitation is unlikely to occur. On the other hand, at the low head operating point, the amount of flowing water relatively increases, and the water of the velocity vector W (solid line) flows into the runner blade 11. At this time, cavitation C may occur on the surface of the runner blade 11 opposite to the side in the rotation direction D during operation of the water turbine (the surface on the side of the second long blade 11LB). This cavitation tends to occur relatively easily in the portion of the runner blade 11 on the side of the band 10. When cavitation occurs, the interwing flow path between the first long wing 11LA and the second long wing 11LB may be blocked.

In the present embodiment, as described above, the wingspan of the long blade 11LB on the band 10 side portion 11LB-b can be shorter than the blade length on the crown 9 side portion 11LB-c. As a result, in the portion of the runner blade 11 on the band 10 side where cavitation tends to occur relatively easily, the interwing flow path between the first long blade 11LA and the second long blade 11LB is expanded. Can be done. Therefore, it is possible to suppress the blockage of the interwing flow path due to cavitation.

As described above, according to the present embodiment, when the runner 5 is viewed from the downstream side during water turbine operation, the connection point 14 between the outlet edge line 13 of the second long wings 11LB and the band 10 is the exit edge line. It is located on the side of the rotation direction D with respect to the line 16 passing through the connection point 15 between the 13 and the crown 9 and the rotation center O of the runner 5. As a result, in the portion of the runner blade 11 on the band 10 side where cavitation tends to occur relatively easily, the interwing flow path between the first long blade 11LA and the second long blade 11LB is expanded. Can be done. Therefore, it is possible to suppress the blockage of the interwing flow path due to cavitation and improve the cavitation performance.

(Sixth Embodiment)
Next, the runner of the hydraulic machine and the hydraulic machine according to the sixth embodiment will be described with reference to FIG.

In the sixth embodiment shown in FIG. 10, when the runner is viewed from the downstream side during water turbine operation, the connection point between the outlet edge line of the long wing and the crown is the connection point between the exit edge line and the band. It is mainly different in that it is located on the side in the rotation direction from the line passing through the center of rotation of the runner, and the other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 3. In FIG. 10, the same parts as those of the first embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 10, the outlet edge lines 13 of the long wings 11LA and 11LB and the crown 9 are connected at the connection point 15. Further, the outlet edge line 13 of the long wings 11LA and 11LB and the band 10 are connected to the connection point 14. In the present embodiment, the long wings 11LA and 11LB are formed so that the connection point 15 is located on the rotation direction D side of the line 16 passing through the connection point 14 and the rotation center O of the runner 5.

In this case, the wingspan of the long wings 11LA and 11LB on the side of the crown 9 can be shortened. As a result, the interwing flow path between the first long blade 11LA and the second long blade 11LB can be expanded on the exit side of the runner 5 where the space is relatively small. Therefore, it is possible to secure a space for welding work of the long wings 11LA and 11LB, and it is possible to improve workability at the time of manufacturing.

Here, in general, when the blade length of the runner blade 11 is shortened, the blade load applied to one runner blade 11 increases. Then, as described in the first embodiment, when the blade load applied to one runner blade 11 increases, the pressure of the negative pressure surface 11N decreases, which may cause a problem of cavitation. Also, in general, cavitation tends to occur relatively easily in the portion of the runner blade 11 on the side of the band 10.

On the other hand, in the present embodiment, the wingspan of the long wings 11LA and 11LB on the band 10 side is maintained in a long state. As a result, it is possible to suppress an increase in the blade load in the portion of the long blades 11LA and 11LB on the band 10 side where cavitation tends to occur relatively easily. Therefore, it is possible to suppress a decrease in the pressure of the negative pressure surface 11N. Therefore, it is possible to prevent deterioration of cavitation performance.

As described above, according to the present embodiment, when the runner 5 is viewed from the downstream side during water turbine operation, the connection point 15 between the outlet edge line 13 of the long wings 11LA and 11LB and the crown 9 is the exit edge line 13. It is located on the side of the rotation direction D with respect to the line 16 passing through the connection point 14 between the band 10 and the rotation center O of the runner 5. As a result, in the portion of the long blades 11LA and 11LB on the crown 9 side, the interwing span between the first long blade 11LA and the second long blade 11LB is widened, and the long blades 11LA and 11LB are welded. Work space can be secured. Further, in the portion on the band 10 side of the long wings 11LA and 11LB, by maintaining the wingspan in a long state, the increase in the wing loading on the band 10 side portion of the long wings 11LA and 11LB is suppressed and negative. It is possible to suppress a decrease in the pressure of the pressure surface 11N. As described above, according to the present embodiment, it is possible to improve the workability at the time of manufacturing and the cavitation performance in a well-balanced manner.

According to the embodiment described above, the cavitation performance can be improved.

Although 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 implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

In the above-described embodiment, an example in which the Francis turbine as an example of a hydraulic machine is a pump turbine capable of performing pump operation has been described. However, the present invention is not limited to this, and the Francis turbine may be configured not to perform pump operation.

1: Francis turbine, 5: runner, 9: crown, 10: band, 11: runner blade, 11A: inlet end, 11B: exit end, 11SA, 11SB: short wing, 11LA, 11LB: long wing, 12A, 12B: Groove weld, 13: Exit edge line

Claims (10)

With the crown,
The band provided on the outer peripheral side of the crown and
A plurality of runner blades provided between the crown and the band.
The plurality of runner blades include a long wing and a short wing having a wingspan shorter than that of the long wing.
Two of the long wings are arranged between the pair of short wings adjacent to each other in the circumferential direction.
Of the two long wings arranged between the pair of short wings adjacent to each other in the circumferential direction, the long wing located on the side in the rotation direction during operation of the water turbine is referred to as the first long wing and the rotation direction. When the long wing located on the opposite side is used as the second long wing, the angle β2A of the outlet end of the first long wing during operation of the water turbine is from the angle β2B of the outlet end of the second long wing. Large, hydraulic machine runner. The hydraulic power according to claim 1 , wherein the two long wings arranged between the pair of short wings adjacent to each other in the circumferential direction are partially formed in the same shape including the inlet end during operation of a water turbine. Machine runner. The runner of the hydraulic machine according to claim 1 , wherein the angle β1A of the inlet end of the first long blade during operation of the water turbine is smaller than the angle β1B of the inlet end of the second long blade. The runner for a hydraulic machine according to any one of claims 1 to 3 , wherein the total number of the short wings and the long wings is an odd number. The long wingspan is joined to the crown and the band via a groove weld, which is a one-sided groove, respectively.
The groove welded portion of the long wing is formed on the side of the short wing adjacent to the long wing from the outlet end during operation of the water turbine to the same radial position as the outlet end of the short wing.
The runner of the hydraulic machine according to any one of claims 1 to 4 . When the runner is viewed from the downstream side during water turbine operation, the two long wings arranged between the pair of short blades adjacent to each other in the circumferential direction are on the side opposite to the rotation direction during water turbine operation. The connection point between the outlet edge line of the long wing and the band is located on the rotation direction side of the line passing through the connection point between the outlet edge line and the crown and the rotation center of the runner. The runner of the hydraulic machine according to any one of claims 1 to 5 . When the runner is viewed from the downstream side during water turbine operation, the connection point between the outlet edge line of the long wing and the crown is the connection point between the outlet edge line and the band and the rotation center of the runner. The runner of the hydraulic machine according to any one of claims 1 to 5 , which is located on the side in the rotation direction during operation of the water turbine with respect to the passing line. The hydraulic machine according to any one of claims 1 to 7 , wherein the inlet end during operation of the long-wing turbine and the inlet end during operation of the short-wing turbine are located at the same radial position. Lanna. The runner for a hydraulic machine according to any one of claims 1 to 8 , wherein one short wing and two long wings are alternately arranged. A hydraulic machine comprising the runner of the hydraulic machine according to any one of claims 1 to 9 .

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