JPH0882276A - Vibration preventing device of water turbine - Google Patents

Abstract

PURPOSE: To eliminate energy loss by providing a draft tube of a Francis turbine with a fin for lessening the momentary pressure variation caused by whirling of a vortex from a runner to prevent vibration when load is applied to a part of a water turbine in such a manner that when the momentary pressure variation is small, such as the time of rated load, it will not be a resistance to the stream of water in the draft tube. CONSTITUTION: An operation chamber 12 disposed on the concrete 8 in such a manner as to open to the tube surface of a draft tube 6 is provided with a prismatic movable fin 11 which is forced to go in and out the operation chamber by a fluid pressure cylinder 13, whereby when the momentary pressure variation is small, such as the time of rated load, the movable fin 11 is moved below the tube surface of the draft tube 6 by the fluid pressure cylinder 13 to be stored in the operation chamber 12. On the other hand, when the momentary pressure variation is large such as the time of partial load, the movable fin 1 is projected over the tube surface of the draft tube 6 by the fluid pressure cylinder 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration device for a water turbine, which prevents vibration due to fluctuations in water pressure generated in a suction pipe of the water turbine.

[0002]

2. Description of the Related Art During the operation of a Francis turbine or a propeller turbine, the vortex generated in the water flowing through the runner due to the rotation of the runner swirls and flows into the suction pipe. FIG. 7 is a diagram showing the whirling of the above-mentioned vortex, which includes the casing 1, the stay vanes 2,
In the Francis turbine consisting of the guide vanes 3, the runner 5, and the suction pipe 6, the vortex 7 generated in the water flowing out from the runner 5 during the partial load operation of the turbine swirls and flows into the suction pipe 6.

Here, the whirling of the vortex 7 causes fluctuations in water pressure in the suction pipe 6, and the fluctuations in water pressure are 30 to 30 with respect to the partial load outside the design point, that is, the rated turbine output.
Around 60% is large. FIG. 8 shows the relationship between the hydraulic pressure fluctuation value of a Francis turbine and the turbine output, for example, and it is understood from the figure that the hydraulic pressure fluctuation is large near a partial load of 30 to 60%. Therefore, in the partial load in the vicinity of this, the water pressure fluctuation causes vibration in the water turbine and the generator equipped with this water wheel.

A phenomenon similar to the above is also observed in off-cam operation of Kaplan turbines and mixed-flow turbines (which means an operating state in which the opening degrees of the runner vanes and guide vanes, which are normally interlocked, do not interlock on the partial load side). . A Francis turbine shown in FIG. 9 is known as a Francis turbine equipped with a means for reducing the fluctuation of water pressure that causes such vibration. In FIG. 9, the Francis turbine includes a casing 1, a stay vane 2, a guide vane 3, a runner 5 attached to the main shaft 4, and a suction pipe 6. In addition, 8 is the poured concrete.

Here, on the pipe surface of the suction pipe 6, there is provided a fin 10 in the shape of a triangular prism that breaks the vortex generated at the time of the partial load to reduce the fluctuation of water pressure. With such a configuration, the water flowing into the casing 1 is rectified by the stay vanes 2 and flows into the guide vanes 3, and the guide vanes 3 adjust the amount of water corresponding to the turbine output. The water whose amount has been adjusted flows into the runner 5 and rotates the runner 5,
A power generator (not shown) connected to the main shaft 4 is rotated to generate electric power. The water flowing out from the runner 5 is sucked out by the suction pipe 6
After that, it is discharged to a water discharge channel (not shown).

During operation of the water turbine as described above, the vortex of the water flowing out from the runner 5 into the suction pipe 6 at the time of partial load is crushed by the fins 10 to reduce the water pressure fluctuation, and Vibrations caused by water pressure fluctuations in the generator are prevented.

[0007]

In the method of breaking up the vortex generated by the fins 10 described above, the flow is obstructed by breaking up the vortex in the flow in the suction pipe 6 to cause energy loss. It has been confirmed that the energy loss is about 2% of the rated output according to the result of the field test of the applicant's hydraulic power plant.

It has been confirmed in field tests that the fluctuation of water pressure in the suction pipe 6 also greatly changes depending on the water level in the discharge channel of the power plant and does not always occur during partial load. As mentioned above, fluctuations in water pressure in the suction pipe occur or do not occur depending on the turbine output and the water level in the discharge channel of the power plant. However, if this does not occur, the energy loss of about 2% as described above will effectively utilize hydraulic energy. However, it is required to reduce the water pressure fluctuation by breaking the vortex only when the water pressure fluctuation occurs.

An object of the present invention is to dispose a fin provided for breaking up a vortex generated in a suction pipe of a water turbine so as not to cause energy loss when water pressure fluctuation due to whirling of a vortex which is a source of vibration is small. The purpose of the present invention is to provide a vibration preventing device for a water turbine.

[0010]

In order to solve the above-mentioned problems, according to the present invention, when the water turbine is in operation, the fluctuation of the water pressure generated in the suction pipe buried in the concrete is reduced to prevent the vibration caused by the water pressure fluctuation. In an anti-vibration device for a water turbine, a plurality of prismatic movable fins that are freely placed in and out of the suction pipe through the pipe wall of the suction pipe, a fluid pressure cylinder that moves the movable fins in and out, and an opening in the pipe surface of the suction pipe. It is installed inside the concrete, and the movable fin goes in and out,
And an operation chamber in which a fluid pressure cylinder is installed.

Further, in the above vibration preventing device for a water turbine, a plurality of flat plate-like movable fins which are pin-coupled to a fixed pin provided on the pipe wall of the suction pipe and are rotatably arranged around the fixed pin, A fluid pressure cylinder for rotating the movable fin, and an operation chamber provided in the concrete that opens to the pipe surface of the suction pipe and in which the fluid pressure cylinder is installed are provided.

Further, in the above-described vibration preventing device for a water turbine, a prismatic movable fin having a shaft that rotatably rotates along a pipe surface of the suction pipe through a shaft that penetrates a pipe wall of the suction pipe. And a rotating means connected to the shaft that penetrates the suction pipe, and an operation chamber provided in the concrete facing the suction pipe and in which the rotating means is installed.

The rotating means is assumed to be an electric motor.

[0014]

Operation: A plurality of prismatic movable fins that move into and out of the suction pipe through the pipe surface of the suction pipe that is embedded in concrete, and a fluid pressure cylinder that moves in and out of the movable fin and that of the suction pipe By opening in the pipe surface and installing in the operation room provided in concrete,
When whirling whirls occur under partial load of a water turbine and water pressure fluctuations are large, the fluid pressure cylinder is operated to cause the movable fins to project from the pipe surface of the suction pipe, and this projecting portion breaks the vortex to create a vortex The water pressure fluctuation is reduced by inhibiting the movement and suppressing the growth, and the vibration due to the water pressure fluctuation is prevented.

On the other hand, when the fluctuation in water pressure is small as in the case of the rated load, the movable fin is recessed from the pipe surface of the suction pipe by the fluid pressure cylinder and is housed in the operation room.
Since the flow of water in the suction pipe is not obstructed, there is no energy loss. Also, a plurality of flat plate-like movable fins that rotate around fixed pins provided on the pipe wall of the suction pipe embedded in concrete, and a fluid pressure cylinder that rotates the movable fins by a piston rod crank-connected. , By providing this fluid pressure cylinder with an operation chamber opened in the pipe surface of the suction pipe and installed in the concrete, when the water pressure fluctuation in the suction pipe is large due to whirling of the vortex during partial load of the water turbine, By operating the fluid pressure cylinder, a flat plate-shaped movable fin is erected from the pipe surface of the suction pipe via the piston rod, and this movable fin breaks up the vortex as described above to reduce the water pressure fluctuation, and the vibration due to the water pressure fluctuation is reduced. To prevent.

On the other hand, when the water pressure fluctuation in the suction pipe is small, such as at the rated load, the fluid pressure cylinder is operated to rotate the flat plate-shaped movable fin through the piston rod to move the pipe surface of the suction pipe. By making the surfaces flush, the flow of water in the suction pipe is not obstructed and energy loss is eliminated. Also, a prismatic movable fin that has a shaft that penetrates the pipe wall of the suction pipe and that rotates through the pipe surface of the suction pipe that is embedded in concrete, and a shaft that penetrates the suction pipe,
When the water pressure fluctuation in the suction pipe is large due to the whirling of the vortex at the partial load of the water turbine by connecting the rotating means facing the suction pipe and installed in the operation room provided in the concrete, to the electric motor as this means. In addition, by rotating the prismatic movable fin via the shaft by the electric motor, the flow of water in the suction pipe is obstructed, that is, the vortex is broken by the movable fin as described above. To reduce fluctuations in water pressure and prevent vibrations due to fluctuations in water pressure.

On the other hand, when the water pressure fluctuation in the suction pipe is small such as when the load is rated, the movable fin of the prismatic shape is rotated by the electric motor through the shaft so as to be positioned along the water flow in the suction pipe. As a result, there is no resistance to the flow of water, so there is no energy loss.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a sectional view of a suction pipe of a Francis turbine equipped with a vibration preventing device according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. In FIGS. 1 and 2 and FIGS. 3 to 6 described later, the same parts as those in the conventional example of FIG. 9 are designated by the same reference numerals, and the description thereof will be omitted. 1 and 2 are different from the conventional example as follows.

The movable fin 11 is in the shape of a pentagonal prism, the portion projecting from the tube surface of the suction pipe 6 is a triangular prism portion 11a, and the portion connected to this triangular prism portion 11a is the square prism portion 11a.
b is formed to form a pentagonal prism. The operation chamber 12 is provided in the concrete 8 by opening on the pipe surface of the suction pipe 6, and the movable fin 11 can be housed in the operation chamber 12 by sliding the side surface of the quadrangular prism portion 11b.

The fluid pressure cylinder 13 is installed in the operation chamber 12, and its piston rod 14 is connected to the bottom of the movable fin 11. The device including the movable fin 11 and the fluid pressure cylinder 13 is provided at four locations in the suction pipe 6 in the drawing, but may be provided at three locations. With such a configuration, when the water pressure fluctuation due to whirling of the vortex inside the suction pipe 6 is large when the turbine is partially loaded, the operation chamber 1
The fluid pressure cylinder 13 in 2 is operated by the fluid to move the movable fin 11 into the suction pipe 6 by the piston rod 14, and the triangular prism portion 11a of the movable fin 11 is sucked into the suction pipe 6
Project from the tube surface of. The vortex in the suction pipe 6 flowing in from the runner 5 due to the protrusion of the movable fin 11 is crushed by the movable fin 11 and the water pressure fluctuation is reduced as described above, and the vibration due to the water pressure fluctuation is prevented.

On the other hand, when the water pressure fluctuation in the suction pipe 6 is small as in the rated load, the fluid pressure cylinder 13 in the operation chamber 12 is operated by the fluid to move the movable fin 11 by the piston rod 14 to the suction pipe 6 Of the suction pipe 6 so that it does not protrude from the pipe surface of the suction pipe 6. The position of the movable fin 11 in this state is indicated by a broken line in P and Q of FIG.

Since the movable fin 11 is not projected to the pipe surface of the suction pipe 6 in this manner, the flow of water in the suction pipe 6 is not blocked by the movable fin 11, so that there is no energy loss. Although the Francis turbine has been described in the above embodiment, the same effect as described above can be obtained also by providing the movable fins 11 in the propeller turbine, the Kaplan turbine, and the mixed flow turbine.

FIG. 3 is a sectional view of a suction pipe of a Francis turbine equipped with a vibration preventing device according to a second embodiment of the present invention, and FIG. 4 is a sectional view taken along line BB of FIG. 3 and 4 are different from the conventional example as follows. The movable fin 18 has a flat plate shape, and has a fixed pin 19 provided on the pipe wall of the suction pipe 6.
And is rotatable around the fixed pin 19.

A fluid pressure cylinder 21 for rotating the movable fin 18 is installed in the operation chamber 20, and the operation chamber 20 is provided in the concrete 8 with an opening on the pipe surface of the suction pipe 6. Fluid pressure cylinder 2
1, the piston rod 22 is connected to the back side of the movable fin 18 by a crank mechanism 23. Therefore, due to the reciprocating movement of the piston rod 22 of the fluid pressure cylinder 21,
The movable fin 18 is fixed to the fixed pin 1 via the crank mechanism 23.
Rotate around 9.

The movable fin 18 and the fluid pressure cylinder 2
The device consisting of 1 and 4 is provided in the suction pipe 6 at four positions in the figure, but may be provided at three positions. With such a configuration,
When the water pressure fluctuation due to whirling of the vortex is large in the suction pipe 6 at the time of partial load, the piston rod 22 is moved toward the suction pipe 6 by the operation of the fluid in the fluid pressure cylinder 21, and the crank mechanism 23 is used. The movable fin 18 is erected on the pipe surface of the suction pipe 6. By raising the movable fin 18, the vortex is crushed by the movable fin 18, the water pressure fluctuation is reduced as described above, and vibration due to the water pressure fluctuation is prevented.

On the other hand, when the fluctuation of the water pressure in the suction pipe 6 is small as in the case of the rated load, if the piston rod 22 of the fluid pressure cylinder 21 is rotated in the opposite direction to the side opposite to the suction pipe 6, The movable fin 18 is flush with the pipe surface of the suction pipe 6. Therefore, the flow of water in the suction pipe 6 is not obstructed by the movable fins 18, so that energy loss is eliminated.

In FIG. 4, R and S are movable fins 1.
8 stands on the pipe surface of the suction pipe 6, and T and U show the state in which the movable fin 18 is flush with the pipe surface of the suction pipe 6. Although the Francis turbine has been described in this embodiment,
Providing the movable fins 18 and the like in the propeller turbine, the Kaplan turbine, and the mixed flow turbine also achieves the same effect as described above.

FIG. 5 is a cross-sectional view of a suction pipe of a Francis turbine equipped with a vibration preventing device according to a third embodiment of the present invention.
The difference from the conventional example in FIG. 5 is as follows. The movable fin 25 includes a middle portion 25a and tip portions 25b connected to both sides of the middle portion 25a. The middle portion 25a has a triangular prism shape having a roof portion 25c at its center portion, while the tip portion 25b extends from the middle portion 25a and the roof portion 25c. Has a triangular pyramid shape connected to the pipe surface of the suction pipe 6. The movable fin 25 is rotatably arranged along the pipe surface of the suction pipe 6 via a shaft 26 described later. Here, a shaft 26 that penetrates the tube wall of the suction pipe 6 is attached to the central portion of the movable fin 25, and the movable fin 25 can rotate in the direction of the arrow via the shaft 26.

The operation chamber 27 is provided in the concrete 8 so as to face the back side of the suction pipe 6, and an electric motor 28 as a rotating means is installed. The shaft 26 penetrating the wall of the suction pipe 6 of the movable fin 25 is directly connected to the shaft of the electric motor 28. In addition, such a movable fin 25 and an electric motor 28
In the figure, the device consisting of and is provided at four locations on the suction pipe 6, but it may be provided at three locations.

With such a configuration, when the water pressure fluctuation is large due to the whirling of the vortex in the suction pipe 6 when the turbine is partially loaded, the movable fin 25 is driven by the electric motor 28 to resist the flow of water in the suction pipe 6. When the vortex is rotated to the position where the water pressure occurs, the vortex hits the movable fin 25 and is crushed, the water pressure fluctuation becomes small as described above, and vibration due to the water pressure fluctuation is prevented. On the other hand, when the water pressure fluctuation in the suction pipe 6 is small as in the rated load, the movable fin 25 is parallel to the water flow by the electric motor 28 so as not to become a resistance against the water flow in the suction pipe 6. When rotated to the position, there is no flow resistance and thus no energy loss.

Although the tip portion 25b of the movable fin 25 has a triangular pyramid shape in this embodiment, it may have another shape. FIG. 6 is a sectional view of a suction pipe of a Francis turbine equipped with a vibration prevention device according to a fourth embodiment of the present invention. In FIG. 6, movable fins 30 and 31 that are obtained by dividing the movable fin 25 shown in FIG.
The electric motors 32 and 33 that rotate 1 respectively are
35 is the same as that shown in FIG. Although the movable fins 30, 31 and the like are provided in the suction pipe 6 at four positions in the drawing, they may be provided at three positions.

With such a structure, the same effect as that shown in FIG. 5 can be obtained. Although the Francis turbine has been described in the embodiments of FIGS. 5 and 6, the propeller turbine, the Kaplan turbine,
The movable fin 25 and the movable fin 30,
By providing 31 or the like, the same effect as described above can be obtained.

[0033]

As is apparent from the above description, according to the present invention, according to the above-mentioned configuration, when the prismatic movable fin has large water pressure fluctuation due to whirling of the vortex during partial load of the water turbine, By projecting from the pipe surface of the suction pipe, the vortex is crushed to reduce the water pressure fluctuation to prevent vibration of the water turbine, and when the water pressure fluctuation is small such as at rated load, the movable fin is recessed from the pipe surface of the suction pipe. By doing so, the flow of water is not obstructed, and energy loss can be eliminated.

According to the second aspect of the present invention, when the water pressure fluctuation of the flat plate-shaped movable fin is large due to the whirling of the vortex at the time of partial load of the water turbine, it is erected from the pipe surface of the suction pipe so as to break the vortex and change the water pressure. By reducing the vibration of the water turbine to prevent vibration of the water turbine, and when the water pressure fluctuation is small such as when the load is rated, the movable fins are made flush with the pipe surface of the suction pipe so that the water flow is not obstructed. Loss can be eliminated.

In the third and fourth aspects, the prismatic movable fin rotatable on the pipe surface of the suction pipe is rotated, and when the water pressure fluctuation is large due to the whirling of the vortex during partial load of the water turbine, the movable fin is rotated. Then, it rotates to a position where it becomes a resistance to the flow of water, crushes the vortex hitting this to reduce the water pressure fluctuation to prevent vibration of the water turbine, and when the water pressure fluctuation is small such as at rated load, the movable fin Can be rotated to a position parallel to the flow of water so as not to become a resistance to the flow of water, thereby eliminating the resistance to the flow of water and eliminating energy loss.

By each of the above means, the loss due to the fin can be minimized, and the loss of about 2% of the rated output in the state where the conventional fin is always attached is eliminated by using the movable fin. be able to.

[Brief description of drawings]

FIG. 1 is a sectional view of a suction pipe of a Francis turbine equipped with a vibration prevention device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a sectional view of a suction pipe of a Francis turbine equipped with a vibration prevention device according to a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG.

FIG. 5 is a sectional view of a suction pipe of a Francis turbine equipped with a vibration prevention device according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a suction pipe of a Francis turbine equipped with a vibration prevention device according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a state of vortices generated in the suction pipe of the Francis turbine.

FIG. 8 is a diagram showing a relationship between a hydraulic pressure fluctuation value of a Francis turbine and a turbine output.

FIG. 9 is a partial cross-sectional view of a conventional Francis turbine in which fins are provided in a suction pipe to reduce fluctuations in water pressure.

[Explanation of symbols]

 6 Suction Pipe 11 Movable Fin 12 Operation Chamber 13 Fluid Cylinder 18 Movable Fin 19 Fixed Pin 20 Operation Chamber 21 Fluid Pressure Cylinder 25 Movable Fin 26 Shaft 27 Operation Room 28 Electric Motor 30 Movable Fin 31 Movable Fin 32 Electric Motor 33 Electric Motor 34 Operation Room 35 Control room

Claims (4)

[Claims] 1. A vibration preventive device for a water turbine, which reduces fluctuations in water pressure generated in a suction pipe buried in concrete during operation of a water turbine to prevent vibration caused by the fluctuations in water pressure, in a suction pipe through a pipe wall of the suction pipe. A plurality of prismatic movable fins that can be freely moved in and out, a fluid pressure cylinder that moves the movable fins in and out, and a fluid pressure cylinder that opens and closes in the concrete surface with an opening on the pipe surface of the suction pipe. An anti-vibration device for a water turbine, which is provided with an operation room to be installed. 2. A vibration preventive device for a water turbine that reduces fluctuations in water pressure generated in a suction pipe buried in concrete during operation of a water turbine to prevent vibrations caused by the fluctuations in water pressure, and is fixed to a pipe wall of the suction pipe. A plurality of flat plate-shaped movable fins that are pin-coupled to the pin and rotatably arranged around the fixed pin, a fluid pressure cylinder that rotates the movable fins, and an opening in the pipe surface of the suction pipe that is placed in the concrete. A vibration preventing device for a water turbine, which is provided with an operation chamber in which a fluid pressure cylinder is installed. 3. A vibration preventive device for a water turbine, which reduces fluctuations in water pressure generated in a suction pipe buried in concrete during operation of a water turbine to prevent vibration caused by the fluctuations in water pressure, and sucks out along a pipe surface of the suction pipe. A prismatic movable fin provided with the shaft that rotates through a shaft that penetrates the pipe wall of the pipe, a rotating means that connects to the shaft that penetrates the suction pipe, and a concrete pipe facing the suction pipe. An anti-vibration device for a water turbine, which is provided with an operation chamber in which a rotating means is installed. 4. A vibration preventing device for a water turbine according to claim 3, wherein the rotating means is an electric motor.