JP2020094509A - Cross-flow water turbine - Google Patents

Abstract

To provide a cross-flow water turbine capable of preventing or suppressing occurrence of cavitation with small loss, as water flow moves along a wall surface of a guide vane without expanding, by a separation area formed by air supplied to a space between the guide vane and a runner even when the guide vane is throttled.SOLUTION: In a cross-flow water turbine including a water conduit pipe, a discharge pipe, a casing having an inner surface shape to guide inflow water from the water conduit pipe, a runner which is rotatably supported in the casing and of which a rotating shaft is disposed in a lateral direction, a guide vane disposed in the casing in a manner that its opening can be changed to adjust a flow rate of water flow in the casing, and a housing having a flow channel communicated with the discharge pipe from the casing, a separation area is formed by the air by supplying the air to a space between the guide vane and a casing lower wall, and the inflow water in the space is made to flow along a surface of the guide vane without expanding toward a downstream side by the separation area.SELECTED DRAWING: Figure 4

Description

The present invention relates to a cross flow turbine. More specifically, air is supplied to the space (gap) between the guide vane and the runner, and a separation area is formed, so that the running water does not spread and flows along the surface of the guide vane. : Cross-flow turbine for preventing or suppressing the occurrence of cavity phenomenon).

In recent years, interest in natural energy has increased, and solar power generation, wind power generation, or hydroelectric power generation has been in the spotlight.

In particular, as a measure to prevent global warming, which is one of the conservation of the global environment, reduction of greenhouse gas emissions represented by carbon dioxide is required in power generation as well. Power generation is receiving attention again. Furthermore, hydropower can generate stable power throughout the day and night.

As a hydroelectric power generation device that generates electric power without building a dam, attention has been paid to a hydrographic small hydroelectric power generation. This small hydroelectric power generation is required to have a structure capable of efficiently generating power even with a low head and small flow rate. The hydroelectric power generation device is expected to become an important pillar for stabilizing the power system. For this reason, multi-faceted research and development has been conducted on various types of turbines, including Francis turbines for small hydropower, pump reversing turbines, horizontal propeller turbines, and cross-flow turbines.

Due to the configuration of the hydroelectric generator, the hydroelectric generator using these turbines has a region where the main flow passing through the machine is disturbed, a region where vortices are generated, a decompression region or a region where cavitation occurs. May appear. In particular, the cavitation region reduces the efficiency of the hydroelectric machine and affects the overall performance of the hydroelectric generator.

Cavitation is a phenomenon (cavity phenomenon) in which a large number of vapor bubbles are generated due to the pressure of the fluid being reduced to near the saturated vapor pressure due to the acceleration of the fluid inside the water turbine. When the bubbles disappear, an extremely high pressure of tens of thousands of atmospheric pressure is locally generated. When the cavitation (air bubbles or vapor bubbles) collapses or vibrates at a high speed, the impact pressure generated acts on the solid surface, thereby damaging the solid surface. Erosion due to the repetition of such impact pressure is called cavitation erosion.

It is also known that if a flow channel (hereinafter, referred to as an “enlarged flow channel”) having a flow channel cross-sectional area that increases from upstream to downstream occurs in the turbine, the turbine efficiency is significantly reduced.

In Japanese Patent Laid-Open No. 8-200199 (Patent Document 1), in a horizontal shaft cylindrical Kaplan turbine equipment, an inspection path is formed as a passage through which an operator enters and exits in order to inspect or maintain bearings and the like in a valve. Along with this, there is disclosed a technique in which an enlarged flow path is not formed by making the flow path cross-sectional area perpendicular to the flow direction of water equal or smaller from upstream to downstream.

Japanese Unexamined Patent Publication No. 1-318763 (Patent Document 2) discloses a turbine blade used for a river water fluid containing earth and sand, which has a work hardening property for a portion that undergoes cavitation, earth and sand abrasion, and composite damage thereof. A turbine blade is disclosed which is excellent in cavitation resistance and earth and sand abrasion resistance by being made of high stainless steel (for example, steel having an austenite structure).

JP-A-1-162720 (Patent Document 3) discloses that jet water during operation of a water turbine is obtained by performing heat treatment (for example, quenching heat treatment by laser beam irradiation) on an area near a lip of a bucket of a water turbine runner, for example, Berton turbine. It discloses a method for increasing fatigue strength against fatigue due to repeated stress due to contact between the two and also improving wear resistance (for example, cavitation erosion resistance and earth and sand abrasion erosion resistance), and a water turbine using the method.

In addition, the cross-flow turbine is a turbine that has been popular since it was used for medium heads but was improved for low heads so that it can be applied to large flows. Generally, a cross-flow turbine has excellent variable flow characteristics and can operate at a relatively high efficiency even at a small flow rate. For example, in JP-A-58-67972 (Patent Document 4) and JP-A-59-138767 (Patent Document 5), in a cross-flow turbine, the amount of water flowing into a runner can be adjusted using guide vanes. Such a configuration is disclosed.

Next, an external perspective view of the conventional cross flow turbine 110 will be described with reference to FIG. Note that, in FIG. 1, in order to make the structure of the cross-flow turbine 110 easy to understand, a part of the casing 113 and the housing 117 is broken so that the inside can be seen.

First, as shown in FIG. 1, a water conduit (water supply pipe) 112 is communicatively connected to an inlet of a casing (runner cover) 113. The runner 114 is housed in the casing 113 and the housing 117. A water wheel shaft (rotating shaft) 114c that extends in the horizontal direction and is parallel to the axis of the runner 114 is rotatably installed. A housing 117 is arranged at the outlet of the casing 113, and the outlet of the housing 117 is connected to the discharge pipe 116. In addition, a guide vane 115 that adjusts the flow rate according to the opening degree is arranged between the runner 114 and the casing 113. In the guide vane type cross flow turbine 110, the runner 114 is rotated by the kinetic energy of water flowing in via the water conduit (inlet tube) 112. Then, the water obtained by rotating the runner 114 is discharged (drained) through the discharge pipe (draft pipe) 116.

Next, FIG. 2 shows a schematic diagram of an internal structure of a horizontal cross section of a main part of the guide vane type cross flow turbine 110. FIG. 3 is a vertical cross-sectional view of the guide vane type cross-flow turbine 110 taken along the cutting line AA shown in FIG. 2, and a schematic view of the internal structure of the main-section vertical cross-section of the cross-flow turbine is shown in FIG. Explain. A water conduit (water supply pipe) 112 is communicatively connected to an inlet of a casing (runner cover) 113 of the cross flow turbine 110. Further, the inlet of the housing 117 is connected to the outlet of the casing 113. The outlet of the housing 117 is communicatively connected to the inlet of the discharge pipe 116. Further, the guide vane 115a rotates about the guide vane shaft 115c as a rotation axis.

Further, as shown in FIGS. 2 and 3, a water wheel shaft (rotating shaft) 114c extending in the horizontal direction is parallel to the axis of the runner 114, and the runner 114 is rotatably installed. The runner 114 has a large number of runner vanes 114a arranged in an annular shape, and is preferably arranged on the outer peripheral portion of the runner 114 at substantially equal pitches. Then, the guide vanes 115 are arranged on the water conduit 112 side of the runner 114. The guide vanes 115 are connected with corresponding levers (not shown) and links (not shown). The opening of the guide vane 115 can be adjusted by operating the lever and the link using a drive system (not shown), so that the guide vane 115 controls the flow rate of the running water. Then, after the running water imparts an impact force or a reaction force to the runner 114, the running water is discharged (discharged) from the discharge pipe 116.

JP-A-8-200199 JP-A-1-318763 JP-A-1-162720 JP 58-67972 A JP-A-59-138777

In a general cross-flow turbine as shown in FIG. 1, when the opening of the guide vane is narrowed, the flow passage cross-sectional area between the guide vane and the casing lower side wall expands from upstream to downstream. That is, an enlarged flow path is formed. Then, as the opening of the guide vanes is reduced, water flow separation and cavitation occur in the enlarged flow path, and due to the loss due to this, the turbine efficiency (η/ηmax) sharply decreases. Further, as a result, the flow at the inlet of the runner changes, so that separation or loss of the runner vanes is likely to occur, but the efficiency of the water turbine also decreases.

First, the invention described in Patent Document 1 relates to a horizontal axis cylindrical Kaplan turbine equipment installed in a water flow path surrounded by concrete and equipped with a valve for accommodating a generator, a turbine shaft, a bearing and the like. However, Patent Document 1 does not disclose a technique applied to prevent or suppress the occurrence of cavitation in a cross-flow turbine.

Next, in the water turbine blade described in Patent Document 2, although cavitation resistance and earth and sand abrasion resistance are improved, stainless steel with high work hardening is used, so that it becomes expensive and economical. It is not a typical water wheel. Further, the water turbine described in Patent Document 3 has improved cavitation erosion resistance, but since the quenching heat treatment by laser beam irradiation is performed on the lip of the bucket of the water turbine, maintenance is required, which is an economical water turbine. It can not be said.

Next, regarding the general cross-flow turbine described in Patent Document 4 or 5, although a guide vane is provided to adjust the amount of water flowing into the runner, the guide vane is used to reduce the flow rate. It does not have a structure or a function for preventing or reducing cavitation when the enlarged flow path is formed between the guide vane and the casing wall when the opening degree of is reduced.

The present invention has been made based on the above circumstances, the object of the present invention, the space between the guide vanes and the casing wall, that is, by the separation area formed by the air supplied to the flow passage, The flow path of the flowing water does not expand, and the direction of the flowing water is along the surface of the guide vane. Therefore, it is an object to provide a cross-flow turbine that does not generate cavitation.

The above object of the present invention is to provide a water conduit, a discharge pipe, a casing having an inner surface shape for guiding inflow water from the water conduit, a rotatably supported inside the casing, and a rotation axis arranged in a lateral direction. A housing having a runner, a guide vane arranged in the casing so that the opening can be changed in order to adjust the flow rate of the water flow in the casing, and a flow path communicating from the casing to the discharge pipe. A cross-flow turbine having and, by supplying air to a space between the guide vane and the casing lower side wall, a separation area formed by the air is generated, and by the separation area, The inflow water in the space is achieved by flowing along the surface of the guide vane without spreading toward the downstream side.

Further, the above object of the present invention is that a nozzle wall is arranged between the guide vane and the runner, one side of the nozzle wall approaches the runner, and an opening is provided in the nozzle wall, When the air is supplied to the space through the opening, or the flow passage whose cross-sectional area increases from the upstream to the downstream is an enlarged flow passage, and the separation area causes the guide vane and the runner to By not forming the enlarged flow path in between, or by the air from the cavity portion of the runner flowing into the separation area, the pressure in the separation area rises, by suppressing the occurrence of cavitation, more Effectively achieved.

Further, the above-mentioned object can be achieved by a power generation facility using any one of the above cross-flow turbines.

According to the cross-flow turbine of the present invention, the cross-sectional area of the flowing water does not expand due to the space between the guide vanes and the lower wall of the casing, that is, the separation area formed by the air supplied to the flowing water channel. Since the direction is along the surface of the guide vane, the occurrence of cavitation can be prevented or suppressed.

In addition, a hole is provided in the casing lower side wall (for example, the nozzle wall) of the enlarged flow passage, and air is supplied from the hole so that a separating region filled with air is separated from the lower side wall of the casing so that flowing water separates from the casing lower side wall. By forming it on the side wall side, it is possible to suppress turbulence and friction of running water and prevent or suppress the occurrence of cavitation. The power generation facility using the cross-flow turbine according to the present invention can contribute to the expansion of the application to the high head region, the extension of the life of the device, and the simplification of the maintenance.

And if it becomes possible to operate by narrowing or narrowing the opening of the guide vanes in order to reduce the flow rate of the cross flow turbine of the power generation equipment, not only can the turbine power generation equipment be downsized, but also the cross flow turbine. Can be expected to expand the scope of application.

It is an external appearance perspective view of the conventional cross flow turbine. It is a V-direction arrow view (plan sectional view) of the cross-flow turbine of FIG. 1, and is a schematic diagram of an internal structure of a main-section plane cross section of the cross-flow turbine. FIG. 3 is a vertical cross-sectional view of the cross-flow turbine shown in FIG. 1 taken along the cutting line AA shown in FIG. 2, and is a schematic diagram of an internal structure of a main-section vertical cross-section of the cross-flow turbine. It is a longitudinal cross-sectional view showing an example of the cross-flow water turbine according to the first embodiment of the present invention, and is a view showing a state of water flow when the opening of the guide vane is low. FIG. 4 is an enlarged view of the vicinity of the nozzle wall when the guide vanes are fully closed in the cross-flow turbine according to the first embodiment of the present invention. It is a figure which shows the flowing water channel in the cross-flow turbine which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the cross-flow turbine which concerns on the 2nd Embodiment of this invention. It is an enlarged view of the part pinched|interposed by the guide vane and the runner in the cross-flow turbine which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the cross-flow turbine which concerns on the 3rd Embodiment of this invention.

In the cross-flow turbine according to the embodiment of the present invention, the separation area formed by supplying air to the space between the guide vanes and the runners allows the water flow along the surface of the guide vanes without spreading the flowing water. It is possible to prevent or prevent cavitation from flowing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments described below are merely examples, and are not intended to exclude various modifications and application of techniques not explicitly shown below. That is, the present invention can be implemented by variously modifying (combining the embodiments) without departing from the spirit of the present invention. Further, in the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are schematic and do not necessarily match actual dimensions and proportions. The drawings may include portions having different dimensional relationships and ratios.

(Principle explanation)
First, the basic principle of the present invention will be described.
The cross-flow turbine according to the present invention has a hole formed in the lower side wall of the casing of a general cross-flow turbine to allow the air in the housing on the runner side to flow into the guide vane side spreading passage. ..

A cross-flow turbine equipped with a suction pipe supplies outside air (air) to the inside of the housing in order to prevent the flow from being disturbed by the impingement of the flow of water on the shaft of the runner and to reduce the efficiency.

The pressure in the runner chamber is lower than atmospheric pressure due to the effect of the suction pipe. Therefore, by making a hole in the wall of the housing, this air is naturally supplied into the housing. This air flow rate is adjusted with a valve etc. so that an appropriate negative pressure and water level in the housing can be achieved.

Therefore, the area where the water jet of the runner does not flow and the space between the lower side wall of the casing and the runner are occupied by air. When the guide vanes are squeezed, the water flow through the enlarged flow path formed between the guide vanes and the casing lower side wall contacts the air phase in the runner at the outlet, so the pressure of the water flow here is the pressure of this air phase. Is almost equal to. Also, the air pressures in the runner and the housing are almost equal.

As a result, the pressure in the narrowed portion upstream of the enlarged flow channel is lower than that in the housing.
Therefore, the air on the housing side flows into the enlarged flow path only by opening the hole. Since the air has a low density, the inertial force is small, and the viscosity is also low, so that the viscous force is also small. Therefore, the influence of the pressure difference is dominant, and the air remains in the low-pressure region near the constriction.
This promotes the separation of the water flow from the casing wall, and if the air supply continues, the gas phase region (air phase region) grows and reaches the outlet of the enlarged flow path, and connects with the gas phase (air phase) in the runner. It will be.

Then, a large amount of air flows into the separation area from the outlet side, and the gas separation area becomes almost constant due to the gas phase pressure in the runner chamber. Therefore, the flow velocity becomes almost constant due to the inertia of the water flow, and the cross-sectional area of the water flow becomes almost constant, so that the separation region of the gas phase (air phase) becomes stable.

Cavitation can be prevented because the pressure in the narrowed portion approaches the air pressure in the housing and increases. In the case where only water flow is flowing without supplying air, if separation occurs due to the water flow due to the enlarged flow path, loss occurs and turbine efficiency decreases, but if the cross flow turbine of the present invention eliminates separation of water flow , This will eliminate the decrease in efficiency.

It is better to open the hole near the narrowed part where the pressure becomes low so that air can easily flow in, but when the guide vane is fully closed, the hole should be fully closed so that water does not flow out from the opened hole. At times, it is necessary to open the guide vane on the downstream side of the position where the guide vane contacts the casing downstream wall.

(First embodiment)
A schematic diagram of an internal structure of a longitudinal cross section of a main part of the cross-flow turbine 10 according to the first embodiment is shown as FIG. 4 corresponding to FIG. 3 showing a conventional example. That is, similarly to FIG. 3, FIG. 4 is a vertical cross-sectional view of the cross-flow turbine shown in FIG. 1 taken along the cutting line AA shown in FIG. As shown in FIG. 4, the cross flow turbine 10 draws in a water flow from a water source (for example, a river or a dam) via a water conduit 12.

As shown in FIG. 4, the cross-flow turbine 10 according to the first embodiment is different from the conventional cross-flow turbine 110 shown in FIG. 3 in that a nozzle wall 18 is provided below the housing 13. Although different, they are almost the same in other respects. It should be noted that description of the components common to the cross-flow turbine 10 according to the first embodiment and the conventional cross-flow turbine as shown in FIGS. 2 and 3 will be omitted, but the cross according to the first embodiment will be omitted. The components of the flow turbine 10 are given different reference numerals to clearly distinguish them from the components of the conventional cross flow turbine.

First, as shown in FIG. 4, when the opening degree of the guide vane 15 is increased, the amount of water in the upper water passage 11a of the guide vane 15 and the lower water passage 11b of the guide vane 15 in the water conduit 12 and the casing 13 becomes , Is controlled according to the opening degree of the guide vane 15. Then, as shown in FIG. 4, the nozzle wall 18 of the cross-flow turbine 10 according to the first embodiment is installed so as to be sandwiched between the runner 14 and the guard vane 15 and fixed to the housing 13. .. An air intake hole (hereinafter, also simply referred to as “hole”) 18a is formed in a portion of the nozzle wall 18 that is sandwiched between the runner 14 and the guard vane 15. Then, the air inside the runner 14 is supplied to the space between the runner 14 and the guard vane 15, that is, the flowing water channel G through the air intake hole 18a. The guide vane 15a and the release valve 15a rotate about the guide vane shaft 15c as a rotation axis.

Next, FIG. 5 shows an enlarged view of the vicinity of the nozzle wall 18 in the cross-flow turbine 10 according to the first embodiment. Note that FIG. 5 shows that the contact point S of the guide vane 15 is in contact with the guide vane fully closed point P of the nozzle wall 18. Since the guide vanes 15 are fully closed, water does not enter the inside of the casing 13.

As for the position of the air intake hole 18a, the air intake hole 18a is arranged at a distance L from the guide vane fully closed point P along the nozzle wall 18 in the downstream direction (the distance between the center of the air intake hole 18a and the guide vane fully closed point P). It

Next, the distribution of the running water and the air layer in the casing 13 when the opening of the guide vane 15 is raised from the fully closed opening will be described with reference to FIG.

FIG. 6 shows a state in which a flowing water channel G is formed by separating the contact point S of the guide vane 15 and the guide vane fully closed point P of the nozzle wall 18. Then, as shown in FIG. 6, by forming the flowing water channel G sandwiched between the nozzle wall 18 and the lower portion of the guide vane 15, an enlarged flow channel spreading from the upstream side to the downstream side of the flowing water channel G is formed.

Conventionally, in the enlarged flow path, the pressure of flowing water is reduced to near the saturated vapor pressure, and the water starts to vaporize. Thus, it is known that cavitation occurs due to the generation of many vapor bubbles in the enlarged flow path.

However, as shown in FIG. 6, in the cross-flow turbine of the first embodiment, the enlarged flow passage between the guide vane 15 and the runner 14 is located in the flowing water region F and the separation region H due to the gas phase (air layer). Since they are separated, the occurrence of cavitation can be prevented or suppressed. The reason will be described below. In addition, in FIG. 6, the boundary between the flowing water region F and the separation region H is represented as a separation line D.

First, when the opening degree of the guide vane 15 is increased, the flowing water channel G is formed. Then, when the flowing water channel G is formed, the flowing water f1 enters the flowing water channel G, and the flowing water f2 flowing out from the flowing water channel G collides with the runner vanes 14a and rotates the runner 14. The air in the runner 14 is supplied to the separation area H by the pressure difference between the inside and the outside of the passage without requiring the rotation of the runner 14.

Then, the air supplied from the air intake hole 18a acts to increase the pressure in the enlarged flow path sandwiched between the guide vane 15 and the runner 14. Along with this, low pressure of the flowing water in the flowing water region F, that is, vaporization (boiling) of the water is prevented, so that cavitation in the flowing water region F can be prevented.

(Second embodiment)
Next, a block diagram of the cross flow turbine according to the second embodiment will be described with reference to FIG.
The cross-flow turbine 20 according to the second embodiment is different from the cross-flow turbine 10 according to the first embodiment in that a valve 18b is provided, but the other configurations are substantially the same. Therefore, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The cross flow turbine 20 according to the second embodiment is provided with the valve 18b between the air intake hole 18a of the nozzle wall 18 and the air layer of the runner 14 so that the actual opening degree of the guide vane 15 is determined. Then, controlling the supply of air to the flowing water channel G will be described with reference to the block diagram shown in FIG. 7.

As shown in FIG. 7, the cross flow turbine 20 according to the second embodiment includes a valve 18b, a guide vane driving servomotor 21, a guide vane opening sensor 15a for detecting the actual opening of the guide vane 15, and a guide vane opening sensor 15a. , With.

The cross-flow turbine 20 according to the second embodiment drives the guide vane driving servomotor 21 to adjust the opening of the guide vane 15 to control the amount of flowing water and to actually guide the vane. When the opening degree of 15 is equal to or less than the set value, the turbine drive control unit 22 is provided to prevent or suppress the occurrence of cavitation by supplying the air from the runner 14 to the flowing water channel G via the valve 18b. ..

Next, an example of controlling the opening degree of the guide vanes 15 by the water wheel drive control unit 22 will be described below.

First, the guide vane 15 is provided with a guide vane opening sensor 15a for detecting the actual opening of the guide vane 15. Then, the guide vane opening degree sensor 15a outputs a signal indicating the actual opening degree of the guide vane 15 to the control unit 22a of the cross flow turbine drive control unit 22.

Further, the control unit 22a outputs the result of comparison between the actual opening of the guide vane 15 and the set value of the guide vane opening to the drive unit 22b. Then, the drive unit 22b outputs a signal instructing the valve 18b to open and close based on the comparison result.

Further, regarding the driving of the guide vanes 15, the control unit 22a causes the driving unit 22b to calculate a control command value based on the actual opening degree of the guide vanes 15 and to drive the control command value based on the control command value. 22b. The drive unit 22b outputs a control signal to the guide vane drive servomotor 21. By the control as described above, the opening of the guide vane 15 is brought close to the target opening.

Further, a state in which the area sandwiched between the guide vanes 15 and the runners 14 in the cross-flow turbine 20 according to the second embodiment is enlarged will be described with reference to FIG. 8. As shown in FIG. 8, in the cross-flow turbine 20 according to the second embodiment, a valve 18b is arranged at the tip of the nozzle wall 18 where the air intake hole 18a is extended. When the opening degree of the guide vane 15 is lower than the set value, the valve 18b is opened to operate so as to supply the air inside the runner 14 toward the running water channel G sandwiched between the guide vane 15 and the runner 14. To do. Then, the supplied air prevents the flowing water in the flowing water region F from becoming low in pressure and vaporizing (boiling) the flowing water. As a result, it is possible to prevent or suppress the occurrence of cavitation in the separation area H and the flowing water area F.

(Third Embodiment)
Next, a cross flow turbine 30 according to the third embodiment will be described with reference to FIG.
The cross-flow turbine 30 according to the third embodiment is provided with a pressure sensor 19 in addition to the cross-flow turbine 20 according to the second embodiment, and supplies air to the running water channel G based on the output of the pressure sensor 19. However, other configurations are almost the same. Therefore, the same components as those of the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted.

First, as shown in FIG. 9, the cross-flow turbine 30 includes a pressure sensor 19 penetrating the casing 13 so as to measure the flowing water pressure in the casing 13.

Then, in the cross-flow turbine 30 according to the third embodiment, when the flowing water pressure based on the pressure sensor 19 is equal to or lower than a set value or is a negative pressure, the flowing water channel G sandwiched between the guide vane 15 and the runner 14 is provided. A water turbine drive control unit 32 for preventing cavitation by supplying air from the inside of the runner 14 is provided. That is, in the cross-flow turbine 30 according to the third embodiment, the valve 18b is opened/closed based on the output of the pressure sensor 19 instead of the comparison result between the set value of the opening of the guide vane 15 and the actual opening. The difference is that it controls.

Specifically, the water turbine drive control unit 32 measures the pressure inside the casing 13 based on the output of the pressure sensor 19, and controls to open the valve 18b when the pressure is equal to or lower than a set value or a negative pressure. .. By the above control, the peeling layer H can be formed on the runner 14 side between the guide vane 15 and the runner 14.

Further, a pressure sensor 19 for detecting the pressure inside the casing 13, in particular, in the enlarged flow path sandwiched between the guide vane 15 and the runner 14, is inserted into the casing 13. Then, the pressure sensor 19 outputs the pressure data or the signal converted into the electric signal to the control unit 32 a of the crossflow turbine drive control unit 32.

Further, the control unit 32a outputs the comparison result of the measured pressure data and the pressure data of the set value to the drive unit 32b. Then, the drive unit 32b outputs a signal instructing opening/closing of the valve 18b to the valve 18b based on the comparison result.

As described above, the cross-flow turbine according to the present invention uses the pressure of the air supplied from the hole 18a provided in the wall surface (for example, the nozzle wall 18) of the enlarged flow passage to cause the guide vane 15 and the runner 14 to separate. By forming the separation area H between them, the flow path of the water flow does not expand, and the water flow flows along the surface (wall surface) of the guide vane, so that the water flow is configured not to cause a decrease in water pressure. Therefore, the following special effects are achieved.

That is, in the cross-flow turbine according to the present invention and the power generation equipment (turbine power generation equipment) using the same, it is possible to suppress turbulence and friction of the water flow and prevent or suppress the occurrence of cavitation. Therefore, the power generation equipment using the cross-flow turbine can be applied to a high head region. Further, it is not necessary to specially process the runners (blades) of the water turbine to prevent cavitation. Therefore, repair due to cavitation erosion is unnecessary, and the life of the water turbine can be extended. Since repair due to cavitation erosion is not required, the life of the water turbine can be extended.

Even if the opening of the guide vanes is reduced to reduce the flow rate of the cross-flow turbine of the power generation equipment, if the operation that suppresses the occurrence of cavitation becomes possible, the turbine power generation equipment can be downsized. Not only can this be achieved, but the maintenance and management of the turbine power generation facility can be further simplified. As a result, it is possible to expand the applicable range of power generation equipment using a cross-flow turbine.

Although the embodiments of the present invention have been described with reference to the examples, each example is a preferred example, and other structures or configurations having similar effects and characteristics are within the scope of the present invention. .. Needless to say, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, in the cross-flow turbine according to the embodiment of the present invention, the cross-sectional shape of the air intake hole 18a provided in the nozzle wall 18 is such that the space between the runner and the guide vane is the water flow region F and the separation region (air layer) H. Round shape, square shape, or any other shape may be used as long as it can be separated into and, and the dimension (size) of the cross-sectional shape can be appropriately designed by using the results of experiments or numerical simulations. can do. Similarly, the number, density and distribution of the air intake holes can be appropriately designed by utilizing the results of experiments or numerical simulations.

Further, in the cross-flow turbine according to the embodiment of the present invention, it is preferable that the air intake hole 18a provided in the nozzle wall 18 is provided so as to be along the air flow direction. Further, instead of the air intake hole, if the air intake groove having a long groove shape is adopted, the air can be uniformly sent, and the effect of stable formation of the separation area H is increased. In this way, cavitation in the enlarged flow path is prevented by adjusting the pressure by the air supplied from the vicinity of the location where cavitation had occurred. In addition, the prevention of cavitation allows water to flow stably into the runner, improving the running efficiency of the runner and eliminating the pulsation of water in the area (part) sandwiched between the guide vane and the runner. Noise is reduced.

Further, in the cross-flow turbine 20 according to the second embodiment, the predetermined opening to be compared with the actual opening of the guide vane is set to one, but the opening level to be compared with the actual opening of the guide vane is set. May be set to a plurality, and the opening degree (opening degree) of the valve 18b may be controlled according to the comparison result.

Further, in the cross-flow turbine 30 according to the third embodiment, it has been shown that the pressure sensor 19 is provided to measure the pressure inside the casing 13, but the pressure sensor is installed at a plurality of positions. May be. Further, instead of the pressure sensor, a noise sensor or a sound sensor for measuring noise in the casing 13 may be installed. In that case, in the cross-flow turbine according to the embodiment of the present invention, when the high-frequency component of the signal from the noise sensor or the sound sensor exceeds a predetermined intensity, it is determined that cavitation accompanied by vibration or noise has occurred. Then, in order to suppress the occurrence of cavitation, the air may be controlled to be supplied from the air intake hole.

In the cross-flow turbine 30 according to the third embodiment, a speed sensor may be installed instead of the pressure sensor 19 in order to measure or estimate the speed and the speed distribution of the water flow in the casing. In that case, in the cross-flow turbine according to the embodiment of the present invention, based on the signal from the speed sensor, when the flow velocity becomes equal to or higher than a predetermined intensity, or the flow velocity is biased (for example, loss of flow uniformity). When the value exceeds the tolerance, it may be determined that cavitation has occurred, and in order to suppress the occurrence of cavitation, air may be supplied from the air intake hole. A Pitot tube may be used as the flow velocity sensor.

In each of the embodiments of the present invention, the cross-flow turbine using one guide vane is shown, but two or more guide vanes may be provided. The two guide vanes are used as a first guide vane (not shown) and a second guide vane (not shown), respectively, and the corresponding first runner (not shown) and second runner ( (Not shown) is a tandem system configuration in which the water turbine shaft (shaft portion) extending in the horizontal direction and the shaft cores (shaft centerlines) of the first runner and the second runner are parallel and rotatable. It is suitable to be installed.

Further, the material of the guide vane according to the embodiment of the present invention is not particularly limited, and may be made of metal or synthetic resin, but is lightweight and thin and excellent in strength, for example, vinyl chloride board, glass fiber reinforced plastic. A synthetic resin plate such as FRP (Fiber Reinforced Plastics) such as carbon fiber reinforced plastic, boron fiber reinforced plastic, or aramid fiber reinforced plastic, aluminum, stainless steel or the like is preferable.

Further, the crossflow turbine drive control unit 22 that controls the opening degree of the guide vanes of the crossflow turbine 20 according to the second embodiment of the present invention is based on the target guide vanes and the actual opening degree of the guide vanes 15. , The guide vane drive servo motor 21 is controlled, but the guide vane drive servo motor 21 may be controlled using PID (proportional integral derivative) calculation control.

For example, in the cross flow turbine 20 according to the second embodiment of the present invention, the cross flow turbine drive control unit 22 is provided with a release valve drive speed control unit, and a control target value in the release valve drive servo motor 21 is provided. In response to the detected deviation from the actual rotation speed, the release valve control target value may be subjected to PID (proportional integral derivative) calculation control to control the release valve driving servomotor 21. In the cross-flow turbine according to the second embodiment of the present invention, PI calculation control may be performed instead of the above PID calculation control, or another calculation control method may be adopted.

10, 20, 30, 110 Cross-flow turbine 12, 112 Water conduit 13, 113 Casing 14, 114 Runner 14a, 114a Runner blade (runner vane)
14c, 114c Water wheel axle (shaft part)
15, 115, guide vane 15a guide vane opening sensor 15c, 115c guide vane shaft 16, 116 discharge pipe 17, 117 housing 18 nozzle wall 18a air intake hole (hole)
18b valve 19 pressure sensor 21 guide vane drive servomotor 22, 32 cross flow turbine drive control unit 22a, 32a control unit 22b, 32b drive unit 118 partition plate S contact point P guide vane fully closed point H separation area F water flow area G Flowing channel D Separation line L Distance

Claims (5)

A water guide pipe, a discharge pipe, a casing having an inner surface shape for guiding inflow water from the water guide pipe, a runner rotatably supported in the casing, and a rotation axis arranged laterally, and the inside of the casing. A cross-flow turbine having a guide vane arranged in the casing and a housing having a flow path communicating with the discharge pipe from the casing so that the opening can be changed in order to adjust the flow rate of the water flow. There
By supplying air to the space between the guide vanes and the lower side wall of the casing, a peeling area formed by the air is generated,
The crossflow turbine, wherein the inflow water in the space flows along the surface of the guide vane without spreading toward the downstream side by the separation area. A nozzle wall is arranged between the guide vane and the runner,
One side of the nozzle wall approaches the runner,
An opening is provided in the nozzle wall,
The crossflow turbine according to claim 1, wherein the air is supplied to the space through the opening. A flow passage whose cross-sectional area increases from upstream to downstream is defined as an enlarged flow passage,
The cross flow turbine according to claim 1 or 2, wherein the separation region does not form the enlarged flow path between the guide vane and the runner. The crossflow turbine according to any one of claims 1 to 3, wherein the air from the hollow portion of the runner flows into the separation area, and the pressure in the separation area rises to suppress the occurrence of cavitation. A power generation facility using the cross-flow turbine according to any one of claims 1 to 4.