JP2015071948A - Francis turbine, francis turbine system, and operation method of francis turbine system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Francis turbine that has no guide vane and that can properly operate even when a flow rate and a head drop become larger in variation width.SOLUTION: A Francis turbine 10 which has no guide vane includes a runner 13 which is driven with flowing-in water to rotate, and a draft tube 18 provided downstream of the runner 13. A swivel prevention plate 19 which prevents water flowing out of the runner 13 from circling is provided in the draft tube 18.

Description

  Embodiments described herein relate generally to a Francis turbine, a Francis turbine system, and a method for operating a Francis turbine system.

  Conventionally, a Francis-type water turbine 100 as shown in FIG. 11, which is the most common water turbine used for hydroelectric power generation, is known. During operation of such a Francis turbine 100, water flows from the upper pond through the inlet pipe into the spiral casing 101, and the water flowing into the casing 101 passes through the stay vane 102 and the guide vane 103 from the casing 101. And flows into the runner 104. The runner 104 is rotationally driven by the water flowing into the runner 104, and a generator coupled to the runner 104 via the main shaft 105 is driven to generate power. The water that rotationally drives the runner 104 is discharged from the runner 104 through the suction pipe 106 to the lower pond.

  During this time, by adjusting the opening degree of the guide vane 103, the flow rate of water flowing into the runner 104 is adjusted, and the power generation amount is changed. The guide vane 103 is rotationally driven by an electric drive unit such as a hydraulic drive unit or an electric servo motor via a link mechanism, and thereby the opening degree of the guide vane 103 is adjusted.

  In the case of medium- or large-sized Francis turbines, high-efficiency operation is required in accordance with usage conditions. As a result, the opening of the guide vane is adjusted as described above to adjust the flow rate of water flowing into the runner, and the operation is performed at an efficient operating point. Further, the opening degree of the guide vane is also adjusted in order to adjust the output according to the operation status of the power system.

  On the other hand, in the case of a small Francis turbine, a simpler configuration is often required than a medium or large Francis turbine. Therefore, the guide vanes as described above may be omitted in a small Francis turbine. In this case, it is possible to omit the drive unit for rotating the guide vanes and the link mechanism. As a result, the entire turbine can be greatly simplified, and the initial cost (such as the cost of the turbine itself and the installation cost) can be greatly reduced. Further, in this case, guide vanes that require troublesome maintenance as the movable part are omitted, which can greatly contribute to a reduction in maintenance costs.

  In addition, the pump reverse rotation water turbine which diverted the general purpose pump for water turbines is known as an apparatus which has a function similar to the Francis type water turbine which does not have a guide vane as mentioned above. However, since the Francis turbine without the guide vanes is designed as a turbine, the pump reverse turbine tends to be inferior to the Francis turbine in terms of performance such as efficiency. In addition, centrifugal pumps are often used for pump reverse turbines, but such pumps tend to be larger in outer shape. For this reason, advantages such as performance improvement and downsizing can be obtained by using a Francis type turbine rather than a pump reverse turbine.

  A Francis turbine that does not have guide vanes as described above does not have a flow rate adjusting function. For this reason, there is a problem that proper operation may be difficult when the flow rate of water flowing into the runner and the effective head fluctuate and the operating point deviates from the assumed operating range. In this case, for example, there is a problem that the turbine efficiency is greatly reduced and a vortex called a whirl is formed at the runner outlet.

  That is, depending on the degree of fluctuation of the flow rate and the effective head, the operating point may deviate from the assumed operating range as shown in FIG. 13, and the efficiency of the Francis turbine may be greatly reduced. Further, when the operating point is out of the assumed operating range, a whirl 107 can be formed at the exit of the runner 104 as shown in FIG. Such a whirl 107 is formed by a swirling flow of water that has flowed out of the runner 104. Although the whirl 107 is not formed in the non-turning region as shown in FIG. 13, the whirl 107 can be greatly developed as the flow rate and the effective head fluctuate and the operating point moves away from the non-turning region. If the operating point is out of the assumed operating range, the whirl 107 can become large. When the whirl 107 is formed, water pressure pulsation is caused and vibration and noise are generated in the suction pipe 106. These vibrations and noise increase as the whirl 107 increases.

  By the way, in order to enable an appropriate operation even when the operating point is out of the assumed operating range, a water turbine is known that adjusts the rotational speed of a water turbine using a variable speed generator.

Japanese Patent Laid-Open No. 11-46499 JP 2002-155846 A

  However, the adjustment range of the rotation speed in the variable speed generator is small and is about 10%. For this reason, when the flow rate and the effective head fluctuate greatly, it is difficult to appropriately operate the Francis turbine.

  The present invention has been made in consideration of these points, and is a Francis type water turbine that does not have guide vanes, and is capable of proper operation even when the fluctuation range of the flow rate or the head becomes large. An object of the present invention is to provide a Francis turbine, a Francis turbine system, and a method of operating the Francis turbine system.

  The Francis type turbine having no guide vane according to the embodiment includes a runner that is rotationally driven by inflowing water, and a suction pipe provided on the downstream side of the runner. A swirl prevention plate is provided in the suction pipe to prevent the water flowing out from the runner from swirling.

  In addition, the Francis turbine system according to the embodiment includes a Francis turbine without a guide vane, an inlet pipe that guides water to the Francis turbine, and a removably attached inlet pipe, and flows into the Francis turbine. And a first flow rate adjusting flange having a first opening that defines a minimum flow path area portion of the water. When the first flow adjustment flange is removed, a second flow adjustment flange having a second opening that defines a minimum flow path area portion of water flowing into the Francis turbine is removably attached to the inlet pipe. The channel area of the first opening of the first flow rate adjusting flange and the channel area of the second opening of the second flow rate adjusting flange are different from each other.

  The Francis turbine system according to the embodiment includes a first Francis turbine and a second Francis turbine that do not have guide vanes, a first inlet pipe that guides water to the first Francis turbine, and a first A second inlet pipe for guiding water in the inlet pipe to the second Francis turbine. An opening / closing valve is provided in the second inlet pipe.

  The Francis turbine system according to the embodiment includes a Francis turbine without a guide vane, an inlet pipe that guides water to the Francis turbine, and a bypass pipe that discharges water in the inlet pipe to the lower pond. ing. The bypass pipe is provided with an open / close valve.

  The Francis turbine system according to the embodiment includes a Francis turbine that does not have a guide vane, an inlet pipe that guides water to the Francis turbine, and an inlet valve provided in the inlet pipe. The opening degree of the inlet valve can be adjusted.

  Furthermore, the operation method of the Francis type turbine system according to the embodiment includes a Francis type turbine not having a guide vane, an inlet pipe for guiding water to the Francis type turbine, and an inlet pipe, the opening degree of which can be adjusted. A method for operating a Francis turbine system comprising an inlet valve. In this Francis turbine system, first, whether or not the power generation output of the generator is included in the assumed power generation output range obtained when the Francis turbine is operated in the assumed operation range of the Francis turbine. Determine whether. Thereafter, the opening degree of the inlet valve is adjusted based on the determination result obtained in the determining step.

FIG. 1 is a diagram showing an overall configuration of a Francis turbine that does not have guide vanes in the first embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a view showing a modification of the cross section taken along the line AA of FIG. FIG. 4 is a top view showing a Francis-type water turbine system in the second embodiment of the present invention. FIG. 5A is a view showing a first flow rate adjusting flange in the Francis turbine system of FIG. 4, and FIG. 5B is a view showing a second flow rate adjusting flange. FIG. 6 is a schematic view showing a Francis type turbine system in the third embodiment of the present invention. FIG. 7 is a top view showing the first Francis turbine system of FIG. FIG. 8 is a schematic view showing a modification of the Francis turbine system of FIG. FIG. 9 is a top view showing a Francis turbine system according to the fourth embodiment of the present invention. FIGS. 10A and 10B are diagrams showing examples of the inlet valve shown in FIG. FIG. 11 is a flowchart for explaining an operation method of the Francis turbine system according to the fourth embodiment of the present invention. FIG. 12 is a diagram showing an overall configuration of a Francis turbine having guide vanes. FIG. 13 is a diagram showing a performance curve in a Francis type turbine without a guide vane. FIG. 14 is a view showing a whirl formed at the runner outlet.

  Hereinafter, a Francis type turbine and a Francis type turbine system which do not have a guide vane in an embodiment of the invention are explained with reference to drawings.

(First embodiment)
A Francis turbine and a Francis turbine system according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. Here, as shown in FIG. 1, the Francis turbine 10 is provided between the upper pond 1 and the lower pond 2 (see FIG. 6), and converts the energy of water flowing from the upper pond 1 to the lower pond 2 into rotational energy. To obtain rotational power.

  First, the Francis type turbine system 30 will be described.

  As shown in FIG. 1, the Francis turbine system 30 includes a Francis turbine 10, an inlet pipe (hydraulic iron pipe) 31 that guides water from the upper pond 1 to the Francis turbine 10 when the turbine is operated, and a Francis turbine 10. And a connected generator 32.

  Among these, the generator 32 is comprised so that it may generate electric power with the rotational power of the Francis type water turbine 10 at the time of a water turbine driving | operation. The generator 32 also has a function as an electric motor, and may be configured to rotationally drive a runner 13 described later by supplying electric power. In this case, water in the lower pond 2 can be sucked and discharged to the upper pond 1 through a suction pipe 18 described later, and the Francis turbine 10 can be pumped (pumped).

  Next, the Francis type turbine 10 will be described.

  As shown in FIG. 1, the Francis turbine 10 includes a spiral casing 11 into which water flows from an inlet pipe 31, a plurality of stay vanes 12, and a runner 13. Among these, the stay vane 12 is for guiding the water that has flowed into the casing 11 to the runner 13, and is disposed at a predetermined interval in the circumferential direction, and a flow path through which water flows is formed between the stay vanes 12. .

  The runner 13 is provided so as to be rotatable about the rotation axis X with respect to the casing 11, and is driven to rotate by water flowing from the casing 11 during the water turbine operation. The runner 13 includes a crown 14, a band 15 provided apart from the crown 14, and a plurality of runner blades 16 provided between the crown 14 and the band 15. The runner blades 16 are arranged at a predetermined interval in the circumferential direction, and a flow path through which water flows is formed between the runner blades 16. When the runner blade 16 receives the pressure of the flowing water, the runner 13 rotates to obtain rotational power.

  A main shaft 17 is connected to the crown 14 of the runner 13. The main generator 17 is connected to the generator 32 described above.

  On the downstream side of the runner 13, a suction pipe 18 that guides the water flowing out from the runner 13 to the lower pond 2 is provided. The water flowing out of the runner 13 recovers the pressure by the suction pipe 18 and is discharged to the lower pond 2.

  As described above, the Francis turbine 10 is a guide vane (see reference numeral 103 in FIG. 12) that can be provided upstream of the runner 13, and is a guide vane for adjusting the flow rate of water flowing into the runner 13. Does not have. For this reason, the structure can be simplified and the initial cost and the maintenance cost can be reduced.

  By the way, a swirl prevention plate 19 for preventing the water flowing out from the runner 13 from swirling is provided in the suction pipe 18. The swirl prevention plate 19 prevents the water flowing out of the runner 13 from swirling even when the flow rate or effective head of the water flowing into the runner 13 fluctuates greatly. (See reference numeral 107 in FIG. 14) is prevented from being formed.

  The rotation preventing plate 19 is preferably disposed in a portion (upstream portion) of the suction pipe 18 on the runner 13 side. Thereby, the turning prevention plate 19 can be brought close to the runner 13, and the water flowing out of the runner 13 can be effectively prevented from turning.

  The plate surface 19 a of the rotation preventing plate 19 extends in a direction (rotational axis direction) along the rotational axis X of the runner 13. Here, the plate surface 19a is a surface that coincides with the plane direction of the anti-rotation plate 19 when the anti-rotation plate 19 is viewed as a whole, and the water flowing out of the runner 13 rotates to form a swirl flow. In this case, the swirl flow collides with the surface. Since the plate surface 19a of such a rotation preventing plate 19 extends along the rotation axis direction, a swirl flow that can be formed can be collided to effectively reduce the swirl speed component.

  As shown in FIG. 2, the rotation preventing plate 19 is formed to extend in the radial direction of the runner 13 when viewed from the rotation axis direction of the runner 13. As a result, the plate surface 19a of the rotation preventing plate 19 can be formed substantially perpendicular to the swirl flow that can be formed when viewed from the direction of the rotation axis, and the swirl speed component can be further reduced. .

  Further, the anti-rotation plate 19 is formed so as to extend linearly from a part of the inner surface of the suction pipe 18 through the rotational axis X to the other part of the inner surface of the suction pipe 18 when viewed from the rotational axis direction. Has been. In other words, the anti-rotation plate 19 is formed along a line that defines the diameter of the suction pipe 18. Accordingly, the swirl prevention plate 19 divides the flow path in the suction pipe 18 when viewed from the rotation axis direction in the circumferential direction, and further prevents the water flowing out from the runner 13 from swirling. It is possible to prevent the formation of the whirl at the 13 outlets.

  Both edges on the radially outer side of the rotation preventing plate 19 are joined to the inner surface of the suction pipe 18 by welding or the like. In this way, the turning prevention plate 19 is supported by the suction pipe 18.

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

  When the water turbine operation is performed in the Francis turbine 10 according to the present embodiment, water flows into the casing 11 from the upper pond 1 through the inlet pipe 31. The water flowing into the casing 11 flows from the casing 11 through the stay vane 12 into the runner 13. The runner 13 is rotationally driven by the water flowing into the runner 13. As a result, the generator 32 connected to the runner 13 is driven to generate power. The water flowing into the runner 13 is discharged from the runner 13 through the suction pipe 18 to the lower pond 2.

  During the water turbine operation, when the flow rate of the water flowing into the runner 13 and the fluctuation of the effective head are small and the operation point is within the assumed operation range as shown in FIG. be able to. In particular, when the operating point is in the non-turning region shown in FIG. 13, it is possible to prevent water flowing out from the runner 13 from turning and forming a whirl at the exit of the runner 13. In addition, when the operating point is out of the non-turning region and is within the assumed operating range, the formed whirl is small, and it is possible to avoid driving trouble and to perform driving.

  On the other hand, when the flow rate or effective head flowing into the runner 13 fluctuates greatly and the operating point deviates from the assumed operating range, the water flowing out from the runner 13 turns and a relatively large whirl is formed at the outlet of the runner 13. obtain.

  However, in the present embodiment, the suction pipe 18 is provided with a rotation preventing plate 19 as shown in FIGS. As a result, the water flowing out of the runner 13 can collide with the anti-rotation plate 19 and the rotational speed component can be reduced. For this reason, it can prevent that the water which flowed out from the runner 13 swirls and a whirl is formed in the exit of the runner 13.

  More specifically, the water flowing out of the runner 13 can be effectively prevented from turning in the radially outer portion of the turning prevention plate 19. That is, the swirl flow can be formed biased radially outward (on the inner surface side of the suction pipe 18) by centrifugal force, but the radially outer portion of the swirl prevention plate 19 is disposed at a position where swirl flow can be formed. Therefore, formation of a swirling flow can be effectively prevented at the radially outer portion. Further, it is possible to directly prevent the formation of a whirl at the outlet of the runner 13 in the radially inner portion (the central portion when the suction pipe 18 is viewed from the rotation axis direction) of the turning prevention plate 19. That is, the whirl can be formed inside the swirl flow, but since the radially inner portion of the swirl prevention plate 19 is disposed at a position where the whirl can be formed, the formation of the whirl directly at the radially inner portion is prevented. Can be prevented.

  As described above, according to the present embodiment, the anti-swivel plate 19 is provided in the suction pipe 18, so that the flow rate of water flowing into the runner 13 and the effective head largely fluctuate, and the operation point is assumed to operate. Even if it is out of the range, the Francis turbine 10 that does not have the guide vanes can be appropriately operated. That is, when the operating point deviates from the assumed operating range shown in FIG. 13, the water flowing out from the runner 13 can swirl to form a whirl, but the swirl prevention plate 19 prevents water swirling and the formation of a whirl. it can. For this reason, it can suppress that a water pressure pulsation is caused in the suction pipe 18, and a vibration and a noise generate | occur | produce, and a water turbine can be drive | operated without trouble. As a result, even when the fluctuation range of the flow rate and the effective head becomes large and the operation point is out of the assumed operation range, it is possible to appropriately operate the Francis turbine 10 without the guide vane. The effect which expands the driving | running range rather than the assumed driving | running | working range which was doing can be acquired.

  Further, according to the present embodiment, the turning prevention plate 19 extends in the radial direction of the runner 13 when viewed from the rotation axis direction. As a result, the plate surface 19a of the swirl prevention plate 19 can be formed substantially perpendicular to the swirl flow that can be formed when viewed from the direction of the rotation axis, and swirl of the swirl flow that collides with the plate surface 19a. The speed component can be further reduced. For this reason, the swirling of the water flowing out from the runner 13 can be further prevented, and the formation of a whirl at the exit of the runner 13 can be further prevented.

  Further, according to the present embodiment, the anti-swivel plate 19 is formed on the inner surface of the suction pipe 18 through a rotation axis X from a part of the inner surface of the suction pipe 18 when viewed from the rotation axis direction of the runner 13. It extends to other parts. As a result, the swirl prevention plate 19 can divide the flow path in the suction pipe 18 when viewed from the rotational axis direction in the circumferential direction. For this reason, it can further prevent that the water which flowed out from the runner 13 swirls, and can further prevent that a whirl is formed in the exit of the runner 13.

  In the present embodiment described above, for example, as shown in FIG. 3, two second anti-rotation plates 20 may be further provided. That is, two second anti-rotation plates 20 for preventing the water flowing out from the runner 13 from turning in the suction pipe 18 are provided, and when viewed from the rotation axis direction of the runner 13, One second anti-rotation plate 20 extends radially outward from one plate surface 19a of the anti-rotation plate 19 (first anti-rotation plate) perpendicularly to the one plate surface 19a, and the other second anti-rotation plate 20 The anti-rotation plate 20 extends radially outward from the other plate surface 19a of the first anti-rotation plate 19 perpendicularly to the other plate surface 19a. As a result, the first anti-rotation plate 19 and the two second anti-rotation plates 20 can be arranged in a cross shape when viewed from the rotational axis direction, and the flow path in the suction pipe 18 is circumferentially arranged. Can be divided more finely and evenly. For this reason, the water which flowed out from the runner 13 can be made to collide with the 1st rotation prevention board 19 and the 2nd rotation prevention board 20, and a turning speed component can be reduced further. As a result, it is possible to further prevent the water flowing out from the runner 13 from turning and further prevent the formation of a whirl at the outlet of the runner 13. Note that the second anti-rotation plate 20 is preferably joined to the suction pipe 18 and the first anti-rotation plate 19 by welding or the like.

  Further, in the above-described embodiment, when the rotation preventing plate 19 is viewed from the rotation axis direction of the runner 13, a part of the inner surface of the suction pipe 18 passes through the rotation axis X to pass through the suction pipe 18. The example which was formed so that it might extend in the other part of an inner surface was demonstrated. However, the present invention is not limited to this, and the anti-rotation plate 19 prevents the water flowing out of the runner 13 from rotating and can be supported by the suction pipe 18 when viewed from the direction of the rotation axis. You may form so that it may extend partially in a radial direction.

(Second Embodiment)
Next, a Francis turbine system according to the second embodiment of the present invention will be described with reference to FIGS. 4 and 5.

  The second embodiment shown in FIGS. 4 and 5 is mainly different in that the first flow rate adjustment flange and the second flow rate adjustment flange are interchangeably attached to the inlet pipe. This is substantially the same as the first embodiment shown in FIG. 4 and 5, the same parts as those of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the Francis turbine system 30 according to the present embodiment, as shown in FIG. 4, a first flow rate adjusting flange 42 is detachably attached to the inlet pipe 31. When the first flow rate adjusting flange 42 is detached from the inlet pipe 31, the second flow rate adjusting flange 44 is detachably attached to the inlet pipe 31. That is, the first flow rate adjusting flange 42 and the second flow rate adjusting flange 44 are used interchangeably. The Francis turbine 10 in the present embodiment is not provided with the turning prevention plate 19.

  The first flow rate adjusting flange 42 has a first opening 43 that defines a minimum flow path area portion of water flowing into the casing 11. That is, when the first flow rate adjusting flange 42 is attached to the inlet pipe 31, the flow rate of water flowing into the casing 11 is defined by the first opening 43 of the first flow rate adjusting flange 42. . Similarly, the second flow rate adjusting flange 44 has a second opening 45 that defines a minimum flow path area portion of water flowing into the casing 11, and the second flow rate adjusting flange 44 is attached to the inlet pipe 31. In this case, the flow rate of water flowing into the casing 11 is defined by the second opening 45 of the second flow rate adjusting flange 44.

  As shown in FIG. 5, the flow area of the first opening 43 of the first flow rate adjusting flange 42 and the flow area of the second opening 45 of the second flow rate adjusting flange 44 are different from each other. Here, the flow area of the first opening 43 shown in FIG. 5A is smaller than the flow area of the second opening 45 shown in FIG. For this reason, the first flow rate adjusting flange 42 is preferably used when water is sent from the upper pond 1 at a relatively large flow rate. Thereby, while being able to reduce the flow volume of the water which flows into the runner 13, the resistance provided to the water sent from the upper pond 1 can be increased and the effective head can be reduced. On the other hand, the second flow rate adjusting flange 44 is preferably used when water is sent from the upper pond 1 at a relatively small flow rate. Thereby, while being able to increase the flow volume of the water which flows into the runner 13, the resistance provided to the water sent from the upper pond 1 can be reduced and the effective head can be increased. The exchange of the first flow rate adjusting flange 42 and the second flow rate adjusting flange 44 may be performed when the flow rate of water sent from the upper pond 1 varies depending on the season, such as in the rainy season or the dry season, when the season changes. . Thus, sufficient effects can be obtained without performing frequent replacement work.

  As shown in FIG. 4, the first flow rate adjusting flange 42 and the second flow rate adjusting flange 44 can be disposed between the inlet pipe 31 and the casing 11. However, the present invention is not limited to this, and the first flow rate adjusting flange 42 and the second flow rate adjusting flange 44 can also be arranged in the middle of the inlet pipe 31 and can be arbitrarily installed as long as they can be detachably attached to the inlet pipe 31. It can be arranged at the position.

  As shown in FIG. 4, the inlet pipe 31 preferably includes an inlet pipe main body 40 and an expansion joint 41 provided at an end of the inlet pipe main body 40 on the casing 11 side. The flow rate adjusting flanges 42 and 44 and the expansion joint 41 can be fastened with bolts or the like. Similarly, the flow rate adjusting flanges 42 and 44 and the casing 11 can be fastened by bolts or the like. In this way, the first flow rate adjusting flange 42 and the second flow rate adjusting flange 44 can be detached from the inlet pipe 31 and can be easily replaced.

  Next, a method for replacing the flow rate adjusting flange will be described.

  First, one flow rate adjusting flange (for example, the first flow rate adjusting flange 42) that has already been attached is removed from the inlet pipe 31. In this case, first, the bolt that fastens the first flow rate adjusting flange 42 and the expansion joint 41 of the inlet pipe 31 is removed. Subsequently, the expansion joint 41 is contracted, and a gap is formed between the first flow rate adjusting flange 42 and the expansion joint 41. Thereafter, the bolt that fastens the first flow rate adjusting flange 42 and the casing 11 is removed, and the first flow rate adjusting flange 42 is taken out between the expansion joint 41 and the casing 11. As a result, the first flow rate adjusting flange 42 can be removed from the inlet pipe 31.

  Next, the other second flow rate adjusting flange 44 is attached to the inlet pipe 31. In this case, first, the second flow rate adjusting flange 44 is inserted between the expansion joint 41 and the casing 11 with the expansion joint 41 of the inlet pipe 31 being contracted, and the expansion joint 41 and the casing 11 are fastened by bolts. . Subsequently, the expansion joint 41 is extended. Thereafter, the second flow rate adjusting flange 44 and the expansion joint 41 are fastened by bolts. As a result, the second flow rate adjusting flange 44 can be attached to the inlet pipe 31.

  In this way, the first flow rate adjusting flange 42 attached to the inlet pipe 31 can be replaced with the second flow rate adjusting flange 44. In the same manner, the second flow rate adjusting flange 44 can be replaced with the first flow rate adjusting flange 42.

  As described above, according to the present embodiment, the first flow rate adjusting flange 42 having the first opening 43 that defines the minimum flow path area portion of the water flowing into the casing 11 is removed from the inlet pipe 31, and this A second flow rate adjusting flange 44 having a second opening 45 that defines a minimum flow path area portion of water flowing into the casing 11 is detachably attached to the inlet pipe 31. Accordingly, a flow rate adjusting flange having an appropriate flow path area is selected from the first flow rate adjusting flange 42 and the second flow rate adjusting flange 44 in accordance with the flow rate of the water sent from the upper pond 1 to the inlet pipe 31. Can be attached. Since the flow area of the first opening 43 of the first flow rate adjusting flange 42 and the flow area of the second opening 45 of the second flow rate adjusting flange 44 are different from each other, the water flowing into the runner 13 is different. While changing the flow rate, the effective head can be changed by changing the resistance applied to the water sent from the upper pond 1. As a result, even when the fluctuation range of the flow rate and the effective head becomes large and the operation point is out of the assumed operation range, it is possible to appropriately operate the Francis turbine 10 without the guide vane. The effect which expands the driving | running range rather than the assumed driving | running | working range which has had can be acquired.

  In addition, in this Embodiment mentioned above, the expansion joint 41 of the inlet pipe 31 demonstrated the example provided in the edge part by the side of the casing 11 of the inlet pipe main body 40. As shown in FIG. However, the present invention is not limited to this, and the expansion joint 41 may be provided at an intermediate position of the inlet pipe 31. Even in this case, the first flow rate adjusting flange 42 and the second flow rate adjusting flange 44 can be detached from the inlet pipe 31 and can be easily replaced. Further, the inlet pipe 31 may not have the expansion joint 41 as long as the first flow rate adjusting flange 42 and the second flow rate adjusting flange 44 can be exchanged.

  Moreover, in this Embodiment mentioned above, the example in which the number of the flow volume adjustment flanges exchangeably attached to the inlet pipe 31 was two was demonstrated. However, the present invention is not limited to this, and the number of flow rate adjusting flanges attached to the inlet pipe 31 in an exchangeable manner may be three or more. As a result, the flow rate and the effective head can be finely adjusted, and the operation efficiency can be improved.

(Third embodiment)
Next, a Francis turbine system according to the third embodiment of the present invention will be described with reference to FIGS.

  In the third embodiment shown in FIG. 6 and FIG. 7, the first inlet pipe that guides water from the upper pond to the first Francis turbine, and the water in the first inlet pipe that leads to the second Francis turbine. The main difference is that the two inlet pipes are connected, and other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 and 2. 6 and 7, the same parts as those of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, as shown in FIG. 6, the Francis turbine system 30 includes a first Francis turbine 10A and a second Francis turbine 10B that do not have guide vanes. The first Francis turbine 10A and the second Francis turbine 10B are similar to the Francis turbine 10 shown in FIG. 1 in that a casing 11 into which water flows in and a runner 13 that is rotationally driven by water flowing in from the casing 11 are used. And respectively. A guide vane for adjusting the flow rate of water flowing into the runner 13 is not provided upstream of the runner 13. The Francis type turbines 10A and 10B in the present embodiment are not provided with the turning prevention plate 19.

  As shown in FIGS. 6 and 7, water from the upper pond 1 is guided to the casing 11 of the first Francis turbine 10A by the first inlet pipe 31A. The water in the first inlet pipe 31A is guided to the casing 11 of the second Francis turbine 10B by the second inlet pipe 31B. That is, a branch portion 50 is provided between the first inlet pipe 31 </ b> A and the casing 11, and the upstream end (the end on the upper pond 1 side) of the second inlet pipe 31 </ b> B is connected to the branch 50. Has been. In this way, the water from the upper pond 1 is diverted and sent to the first Francis turbine 10A and the second Francis turbine 10B, and the first Francis turbine 10A and the second Francis turbine 10B operate in parallel. It is configured to be possible.

  An opening / closing valve 51 is provided in the second inlet pipe 31B. Accordingly, a part of the water in the first inlet pipe 31A is led to the casing 11 of the second Francis turbine 10B when the on-off valve 51 is opened. Incidentally, FIG. 6 shows an example in which the water flowing out from the runner 13 of the second Francis turbine 10B joins the water flowing out from the runner 13 of the first Francis turbine 10A and is discharged to the lower pond 2. However, the water flowing out from the runner 13 of the second Francis turbine 10B may be directly discharged to the lower pond 2 without joining the water flowing out from the runner 13.

  When the flow rate of the water sent from the upper pond 1 is within the assumed operation range of the first Francis turbine 10A that is assumed in advance, the on-off valve 51 provided in the second inlet pipe 31B is closed. Thus, the water from the upper pond 1 flows into the casing 11 of the first Francis turbine 10A through the first inlet pipe 31A and is not led to the second inlet pipe 31B.

  When the flow rate of the water sent from the upper pond 1 increases, the on-off valve 51 provided in the second inlet pipe 31B is opened. Thus, the water from the upper pond 1 flows into the casing 11 of the first Francis turbine 10A and the casing 11 of the second Francis turbine 10B. That is, the water from the upper pond 1 is diverted and flows into the first Francis turbine 10A and the second Francis turbine 10B. This can reduce the flow rate of water flowing into the runner 13 of the first Francis turbine 10A.

  As described above, according to the present embodiment, the first inlet pipe is connected to the first inlet pipe 31A for guiding water from the upper pond 1 to the casing 11 of the first Francis turbine 10A, and the first inlet pipe is connected to the casing 11 of the second Francis turbine 10B. The 2nd inlet pipe 31B which guides the water in 31A is connected, and the on-off valve 51 is provided in the 2nd inlet pipe 31B. Accordingly, when the flow rate of water sent from the upper pond 1 increases, the on-off valve 51 provided in the second inlet pipe 31B is opened, and the water from the upper pond 1 is supplied to the first Francis turbine 10A and the second Francis. It can be made to flow into the water turbine 10B. For this reason, the flow volume of the water which flows into the runner 13 of 10 A of 1st Francis type water turbines can be reduced. As a result, even when the fluctuation range of the flow rate and the effective head becomes large and the operating point is out of the assumed operating range, the first Francis turbine 10A having no guide vane can be appropriately operated, It is possible to obtain an effect of expanding the operation range from the assumed operation range assumed in advance. In this case, the second Francis turbine 10B can be operated, and the generator connected to the runner 13 of the second Francis turbine 10B can also generate power. For this reason, the power generation output as the Francis turbine system 30 can be increased by effectively using the increased flow rate of water from the upper pond 1.

  In the above-described embodiment, the first inlet pipe is connected to the first inlet pipe 31A for guiding water from the upper pond 1 to the casing 11 of the first Francis turbine 10A, and the first inlet pipe to the casing 11 of the second Francis turbine 10B. The example in which the second inlet pipe 31B that guides the water in 31A is connected has been described. However, the present invention is not limited to this, and three or more Francis turbines are provided so as to be able to operate in parallel, and a plurality of other inlet pipes including the second inlet pipe 31B are connected to the first inlet pipe 31A. You may be made to do. As a result, even when the fluctuation range of the flow rate or the effective head is further increased, the first Francis turbine 10A having no guide vanes can be operated.

  Further, in the present embodiment described above, the first inlet pipe is connected to the first inlet pipe 31A for guiding water from the upper pond 1 to the casing 11 of the first Francis turbine 10A, and the first inlet pipe to the casing 11 of the second Francis turbine 10B. The example in which the second inlet pipe 31B that guides the water in 31A is connected has been described. However, the present invention is not limited to this. For example, as shown in FIG. 8, even if a bypass pipe 52 that discharges water in the first inlet pipe 31 </ b> A to the lower pond 2 is connected to the first inlet pipe 31 </ b> A, and an open / close valve 53 is provided in the bypass pipe 52. Good. As a result, when the flow rate of the water sent from the upper pond 1 increases, the on-off valve 53 provided in the bypass pipe 52 is opened, and a part of the water from the upper pond 1 is passed through the runner 13 of the first Francis turbine 10A. Can be discharged into the lower pond 2 without flowing into the basin. For this reason, the flow volume of the water which flows into the runner 13 of 10 A of 1st Francis type water turbines can be reduced.

(Fourth embodiment)
Next, with reference to FIGS. 9 and 10, a Francis turbine system and a Francis turbine system operating method according to the fourth embodiment of the present invention will be described.

  In the fourth embodiment shown in FIGS. 9 and 10, an inlet valve is provided in an inlet pipe for guiding water from the upper pond to the casing of the Francis turbine, and the opening degree of the inlet valve can be adjusted. The main difference is that other configurations are substantially the same as those of the first embodiment shown in FIGS. 9 and 10, the same parts as those of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the Francis turbine system 30 in the present embodiment, an inlet valve 60 is provided in the inlet pipe 31. In addition, a control device 61 is connected to the generator 32, and the control device 61 has a display unit (not shown) that indicates the power generation output of the generator 32. Specifically, the generator 32 creates a power generation output signal indicating the power generation output and transmits it to the control device 61, and the power generation output indicated by the transmitted power generation output signal is displayed on the display unit of the control device 61. .

  The opening degree of the inlet valve 60 can be adjusted. As such an inlet valve 60, for example, a partition plate type valve as shown in FIG. 10A or a butterfly valve (butterfly valve) as shown in FIG. 10B can be employed. 10A, the valve body 62a of the inlet valve 60 is configured to be movable in a direction perpendicular to the longitudinal direction (flow direction) of the inlet pipe 31 by the valve body driving portion 63a. Has been. The opening degree of the inlet valve 60 is determined according to the position of the valve body 62a. In the butterfly valve shown in FIG. 10B, the valve body 62b of the inlet valve 60 is configured to be rotatable about an axis extending in a direction orthogonal to the flow direction by the valve body driving portion 63b. The opening degree of the inlet valve 60 is determined according to the angle of the valve body 62b. The valve body driving parts 63a and 63b described above are controlled by the control device 61.

  The adjustment of the opening degree of the inlet valve 60 is preferably performed based on the power generation output of the generator 32. In this case, for example, the operator confirms the power generation output displayed on the display unit of the control device 61, determines whether or not the displayed power generation output is included in the assumed power generation output range, and based on the determination result. The opening degree of the inlet valve 60 can be adjusted. More specifically, when the power generation output at the generator 32 is larger than the assumed power generation output range, the opening degree of the inlet valve 60 is reduced, and when the power generation output at the generator 32 is smaller than the assumed power generation output range, the inlet valve Increase the opening of 60. The opening degree of the inlet valve 60 can be adjusted by sending a drive instruction from the control device 61 to the valve body drive parts 63a and 63b of the inlet valve 60.

  Here, the assumed power generation output range is a range of power generation output of the generator 32 obtained when the Francis turbine 10 is operated in the assumed operation range assumed in advance shown in FIG. When the power generation output obtained in the generator 32 is out of the assumed power generation output range, it can be considered that the flow rate of water flowing into the runner 13 and the effective head fluctuate and the operating point is out of the assumed operation range. For this reason, when the power generation output of the generator 32 is out of the assumed power generation output range, by adjusting the opening degree of the inlet valve 60, the flow rate and the effective head can be adjusted to return the operating point within the assumed operation range. it can.

  An operation method of the Francis turbine system according to the present embodiment having such a configuration will be described below with reference to FIG.

  First, an assumed power generation output range obtained in the generator 32 when the Francis turbine 10 is operated in the assumed operation range as shown in FIG. 13 is calculated (step S1). The calculation of the assumed power generation output range may be performed by an operator or the control device 61.

  Subsequently, the operation of the Francis turbine 10 is started (step S2). As a result, the generator 32 generates power. During this time, the generator 32 creates a power generation output signal indicating the power generation output and transmits it to the control device 61.

  It is determined whether or not the power generation output indicated by the power generation output signal transmitted to the control device 61 is included in the assumed power generation output range (step S3). In this case, the power generation output is displayed on the display unit of the control device 61, and the operator makes a determination by confirming the displayed power generation output.

  Based on the determination result obtained in step S3, that is, when the power generation output is larger or smaller than the assumed power generation output range, the opening degree of the inlet valve 60 is adjusted (step S4). In this case, when the power generation output in the generator 32 is larger than the assumed power generation output range, the opening degree of the inlet valve 60 is decreased. As a result, the flow rate that has increased from the assumed operating range can be reduced, and the resistance given to the water sent from the upper pond 1 can be increased to reduce the effective head, The power generation output can be reduced. On the other hand, when the power generation output of the generator 32 is smaller than the assumed power generation output range, the opening degree of the inlet valve 60 is increased. By this, while being able to increase the flow volume reduced from the assumption operation range, the resistance provided to the water sent from the upper pond 1 can be reduced, and the power generation output of the generator 32 is increased. Can do. In addition, when the electric power generation output in the generator 32 exists in the assumption electric power generation output range, the opening degree of the inlet valve 60 is not adjusted (step S5). Further, the opening degree of the inlet valve 60 is, for example, based on the above-described determination result, the operator operates the control device 61 to give a drive instruction from the control device 61 to the valve body drive parts 63a and 63b of the inlet valve 60. Can be adjusted.

  As described above, according to the present embodiment, the inlet valve 60 capable of adjusting the opening is provided in the inlet pipe 31 that guides water from the upper pond 1. Thereby, while being able to adjust the flow volume of the water which flows into the runner 13, the resistance given to the water sent from the upper pond 1 can be adjusted, and the effective head can be adjusted. For this reason, even when the fluctuation range of the flow rate and the effective head becomes large and the operating point deviates from the assumed operating range, it is possible to appropriately operate the Francis turbine 10 without the guide vane. It is possible to obtain the effect of expanding the operation range from the assumed operation range.

  Moreover, according to this Embodiment, the opening degree of the inlet valve 60 is adjusted based on the determination result which determined whether the electric power generation output in the generator 32 was contained in the assumption electric power generation output range. More specifically, when the power generation output is larger than the assumed power generation output range, the opening degree of the inlet valve 60 is decreased. As a result, the flow rate of water flowing into the runner 13 can be reduced, the resistance given to the water sent from the upper pond 1 can be increased, the effective head can be reduced, and the power generation output can be reduced. On the other hand, when the power generation output is smaller than the assumed power generation output range, the opening degree of the inlet valve 60 is increased. Thereby, while increasing the flow volume of the water flowing into the runner 13, the resistance given to the water sent from the upper pond 1 can be reduced, the effective head can be increased, and the power generation output can be increased. For this reason, the power generation output in the generator 32 outside the assumed power generation output range can be returned to the assumed power generation output range.

  In the present embodiment described above, the operator determines whether or not the power generation output of the generator 32 is included in the assumed power generation output range, and the operator operates the control device 61 based on the determination result. The example in which the opening degree of the inlet valve 60 is adjusted has been described. However, the present invention is not limited to this, and the control device 61, not the operator, may determine whether or not the power generation output of the generator 32 is included in the assumed power generation output range.

  That is, the power generator 32 transmits a power generation output signal indicating the power generation output, and the control device 61 sets the power generation output in the power generator 32 within an assumed power generation output range stored in advance based on the transmitted power generation output signal. It is determined whether or not it is included. And the control apparatus 61 controls the valve body drive part (63a or 63b) of the inlet valve 60 so that the opening degree of the inlet valve 60 may be adjusted based on this determination result. In this case, the control device 61 reduces the opening of the inlet valve 60 when the power generation output indicated by the power generation output signal transmitted from the generator 32 is larger than the assumed power generation output range, and the power generation output falls within the assumed power generation output range. It is preferable to control the inlet valve 60 so as to increase the opening degree of the inlet valve 60 when it is smaller.

  Thus, the opening degree of the inlet valve 60 can be automatically adjusted without intervention of an operator, and the flow rate of water flowing into the runner 13 can be quickly and finely adjusted with respect to the flow rate and the fluctuation of the effective head. It becomes possible to adjust.

  Moreover, in this Embodiment mentioned above, the generator 32 produced | generated the power generation output signal which shows a power generation output, and demonstrated the example transmitted to the control apparatus 61. FIG. However, the present invention is not limited to this. For example, a measuring instrument (not shown) for measuring the power generated in the generator 32 is provided separately from the generator 32, and the measuring instrument generates power output. May be generated and transmitted to the control device 61.

  Although the embodiments of the present invention have been described in detail above, the Francis turbine, the Francis turbine system, and the operation method of the Francis turbine system according to the present invention are not limited to the above-described embodiments. Various modifications can be made without departing from the spirit of the present invention. Moreover, as a matter of course, these embodiments can be partially combined as appropriate within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Francis type water turbine 10A 1st Francis type water wheel 10B 2nd Francis type water wheel 13 Runner 18 Suction pipe 19 Turning prevention plate 19a Plate surface 20 Second turning prevention plate 30 Francis type water turbine system 31 Inlet pipe 31A First inlet pipe 31B First 2 inlet pipe 32 generator 41 expansion joint 42 first flow rate adjusting flange 43 first opening 44 second flow rate adjusting flange 45 second opening 51 on-off valve 52 bypass pipe 53 on-off valve 60 inlet valve 61 controller

Claims (11)

A Francis turbine without a guide vane,
A runner that is rotationally driven by incoming water;
A suction pipe provided downstream of the runner;
A Francis type turbine provided with a turning prevention plate provided in the suction pipe for preventing the water flowing out of the runner from turning.   2. The Francis turbine according to claim 1, wherein the rotation preventing plate extends in a radial direction of the runner when viewed from a direction along a rotation axis of the runner.   The anti-rotation plate extends from a part of the inner surface of the suction pipe to the other part of the inner surface of the suction pipe through the rotation axis when viewed from a direction along the rotation axis of the runner. The Francis turbine according to claim 1 or 2, wherein Two second anti-rotation plates provided in the suction pipe for preventing the water flowing out of the runner from rotating;
When viewed from the direction along the rotation axis of the runner, one of the second anti-rotation plates extends radially outward from one plate surface of the anti-rotation plate perpendicularly to the plate surface, and the other 4. The Francis shape according to claim 1, wherein the second anti-rotation plate extends radially outward from the other plate surface of the anti-rotation plate perpendicularly to the plate surface. 5. Water wheel. Francis turbine without guide vanes,
An inlet pipe for leading water to the Francis turbine,
A first flow adjustment flange removably attached to the inlet pipe and having a first opening defining a minimum flow area area of water flowing into the Francis turbine;
A second flow rate adjustment having a second opening that removably attaches to the inlet pipe when the first flow rate adjustment flange is removed and defines a minimum flow area of water flowing into the Francis turbine A flange, and
The Francis turbine system, wherein a flow path area of the first opening of the first flow rate adjusting flange and a flow path area of the second opening of the second flow rate adjusting flange are different from each other.   The Francis turbine system according to claim 5, wherein the inlet pipe has an expansion joint. A first Francis turbine and a second Francis turbine that do not have guide vanes respectively;
A first inlet pipe for directing water to the first Francis turbine,
A second inlet pipe for guiding water in the first inlet pipe to the second Francis turbine,
A Francis-type water turbine system comprising: an on-off valve provided in the second inlet pipe. Francis turbine without guide vanes,
An inlet pipe for leading water to the Francis turbine,
A bypass pipe for discharging water in the inlet pipe to a lower pond;
A Francis-type water turbine system comprising: an on-off valve provided in the bypass pipe. Francis turbine without guide vanes,
An inlet pipe for leading water to the Francis turbine,
An inlet valve provided in the inlet pipe,
The Francis-type water turbine system characterized in that the opening of the inlet valve can be adjusted. A generator coupled to the Francis turbine,
And a control device,
The control device determines whether or not the power generation output of the generator is included in an assumed power generation output range obtained when the Francis turbine is operated in a presumed operation range of the Francis turbine. 10. The Francis turbine system according to claim 9, wherein the Francis-type water turbine system is controlled so as to adjust the opening of the inlet valve based on the determination result. The Francis turbine system according to claim 9, wherein the Francis turbine system is configured to operate the Francis turbine system further including a generator coupled to the Francis turbine.
Determining whether the power generation output in the generator is included in an assumed power generation output range obtained when the Francis turbine is operated in a presumed operation range of the Francis turbine,
And a step of adjusting the opening degree of the inlet valve based on a determination result obtained in the determination step.

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