JP4690702B2 - Water wheel and control method thereof - Google Patents

Description

  The present invention relates to a water wheel used as a water wheel, a pump water wheel, and the like in a hydroelectric power generation facility and the like and a control method therefor.

  For example, a conventional structure of a water wheel used as a water wheel, a pump wheel, or the like in a hydroelectric power generation facility (see Patent Document 1 below) will be described with reference to the example shown in FIGS. As shown in the figure, the water wheel 1 has a runner 3 provided with a plurality of runner vanes 2 at intervals in the circumferential direction at the center, and the runner 3 is provided at the tip of the main shaft 4. And can be rotated. A plurality of guide vanes 5 and stay vanes 6 are provided in order on the outer peripheral side of the runner 3 at intervals in the circumferential direction, and a casing 7 formed in a spiral shape is provided on the outer peripheral side thereof. It has been. Further, a draft tube 8 having a gradually increased diameter is provided on the lower side of the runner 3.

When the water from the upper pond is fed into the spiral casing 7, the water turbine 1 is gradually fed to the center while turning, and flows into the runner 3 through the stay vane 6 and the guide vane 5. Rotational force is generated by the runner vanes 2, whereby the runner 3 rotates and a rotating shaft of a generator (not shown) connected to the main shaft 4 is rotated to generate electric power.
The water obtained by rotating the runner 3 flows through the draft tube 8 and is sent out to a lower pond or a river. When the water turbine 1 is used as a pump for pumping water, by rotating the main shaft 4, water on the lower pond side is sucked up by the runner 3 from the draft tube 8, and is introduced into the casing 7 from the guide vane 5 and the stay vane 6. It is sent out to Kamiike.

  The angle of the guide vane 5 is individually changed so that the turning speed component from the runner to the draft tube at a small flow rate becomes small. As a result, noise caused by water pressure pulsation in the draft tube 8 caused by the remaining swirling speed component is prevented.

Japanese Patent Laying-Open No. 2003-21039 (see FIGS. 6 and 7)

In general, further improvement in the efficiency of the water turbine at the maximum efficiency point flow rate is always expected.
However, from the disclosure of Patent Document 1, although knowledge about the reduction of the turning speed component can be obtained, how to individually control the guide vane opening degree in order to further increase the efficiency of the water turbine at the maximum efficiency point flow rate. There is no suggestion.

  On the other hand, it is known that the inflow angle distribution of the fluid flowing from the stay vane 6 toward the guide vane 5 is not uniform in the circumferential direction due to the presence of the secondary flow in the casing 7 or the like. If the guide vane rotation angle is individually controlled so that the guide vane follows the flow according to the non-uniform inflow angle distribution, it is expected that the efficiency of the water turbine can be improved.

  However, as a result of intensive studies by the present inventors, it has been found that no significant efficiency improvement is observed even if the guide vane rotation angle is simply individually controlled according to the inflow angle distribution having non-uniformity.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a water turbine that realizes further high efficiency particularly at the time of maximum efficiency point flow rate, and a control method thereof.

In order to solve the above-mentioned problems, the water turbine and the control method thereof according to the present invention employ the following means.
That is, the water wheel according to the present invention includes a runner in which a plurality of runner vanes are provided along the circumferential direction, and a plurality of guide vanes that are provided on the outer peripheral side of the runner and whose rotation angles can be individually changed. , a plurality of stay vanes provided on an outer periphery of the guide vanes, the guide vane angle control means for individually controlling the rotational angle of the guide vanes, in water wheel provided with the guide vane angle of the control means, The rotation angle of each guide vane is set in the vicinity of the design point where the guide vane collision loss with respect to the fluid flowing into the guide vane is the smallest and within the range of the low collision loss region where the guide vane collision loss does not rapidly increase. The individual control is performed as described above.

Even if the rotation angle of the guide vane is set according to the inflow angle distribution in the circumferential direction of the fluid that has passed through the stay vane, the rotation angle that causes a large guide vane collision loss due to the deviation of the incident angle that is the angle of the guide vane to the stream As a result, the efficiency drops. Accordingly, in the present invention, the guide vane rotation angle is set within the range of the low collision loss region. As a result, the guide vane rotation angle is set within a range where the guide vane collision loss does not increase in relation to the flow angle distribution in the circumferential direction of the fluid that has passed through the stay vanes, and a water turbine that is as efficient as possible is realized. Is done.
In particular, it is preferable to perform the individual control as in the present invention near the maximum efficiency point flow rate (for example, about 65% of the guide vane opening).
As individual control performed by the guide vane angle control means, a plurality of guide vanes may be divided into several groups, and the guide vane rotation angle may be controlled for each group. It is good also as a system controlled individually.

  The “low collision loss region” is, for example, about 10 °, preferably about 5 ° on both sides from the design point.

  Further, the guide vane angle control means narrows the setting range of the rotation angle of each guide vane when the flow rate is small than when the flow rate is the highest efficiency point.

When the flow rate of the fluid flowing through the water turbine is small, that is, when the flow rate is small, some guide vane rotation angles deviate from the low collision loss region and show a large collision loss. Therefore, when the flow rate is small, the setting range of the guide vane opening angle is narrower than that at the maximum efficiency point flow rate. The narrowest case corresponds to the case where all the guide vane rotation angles are the same and the individual control is not performed.
“Small flow rate” means a flow rate lower than the maximum efficiency point flow rate, for example, a guide vane opening degree of 30% or less.
The “maximum efficiency point flow rate” means a flow rate when the water turbine exhibits the highest efficiency, for example, near the guide vane opening degree of 65%.

  Further, the guide vane angle control means narrows the setting range of the rotation angle of each guide vane at the time of a large flow rate than at the maximum efficiency point flow rate.

When the flow rate of the fluid flowing through the water turbine is large, that is, when the flow rate is large, some guide vane rotation angles deviate from the low collision loss region and show a large collision loss. Therefore, at the time of a large flow rate, the setting range of the guide vane opening angle is made narrower than that at the maximum efficiency point flow rate. The narrowest case corresponds to the case where all the guide vane rotation angles are the same and the individual control is not performed.
“Large flow rate” means a flow rate exceeding the maximum efficiency point flow rate, for example, a guide vane opening degree of 70% or more.

  Further, the method for controlling a water turbine according to the present invention includes a runner in which a plurality of runner vanes are provided along the circumferential direction, and a plurality of guides that are provided on the outer peripheral side of the runner and whose rotation angles can be individually changed. In a method for controlling a water turbine comprising vanes and a plurality of stay vanes provided on the outer periphery of the guide vanes, the rotation angle of each guide vane is such that the guide vane collision loss with respect to the fluid flowing into the guide vanes is the largest. The individual control is performed so that the guide vane collision loss is set within the range of a low collision loss region in which the guide vane collision loss does not rapidly increase.

  Since the guide vane rotation angle is set within the range of the low collision loss region, the guide vane rotation is performed within the range where the guide vane collision loss does not increase due to the flow angle distribution in the circumferential direction of the fluid that has passed through the stay vane. The moving angle is set, and a water turbine control method that is as efficient as possible can be provided.

  According to the present invention, since the rotation angle of the guide vane is individually set within the range of the low collision loss region, it is possible to set an appropriate incident angle for each guide vane, and as efficiently as possible. Water turbine and its control method can be provided.

A reference embodiment according to the water wheel of the present invention will be described below with reference to the drawings.
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
In FIG. 1, a water turbine 11 has a runner 13 provided with a plurality of runner vanes 12 at the center thereof at intervals in the circumferential direction. The runner 13 is provided at the tip of the main shaft 14 and is rotatable together with the main shaft 14. A plurality of guide vanes 15 and a plurality of stay vanes 16 are provided in order on the outer peripheral side of the runner 13 at intervals in the circumferential direction, and a casing 17 formed in a spiral shape is provided on the outer peripheral side thereof. Is provided.
On the lower side of the runner 13, a draft tube 18 that is gradually enlarged in diameter and bent in the middle is provided.

  According to the water turbine 11 configured in this manner, water from the upper pond is fed into the spiral casing 17 and gradually fed to the center while turning, and flows into the runner 13 through the stay vane 16 and the guide vane 15. Rotational force is generated by the runner vane 12 of the runner 13. As a result, the runner 13 rotates and a rotating shaft of a generator (not shown) connected to the main shaft 14 is rotated to generate electric power.

  The water obtained by rotating the runner 13 flows through the draft tube 18 and is sent out to the lower pond.

  When the water turbine 11 is used as a pump for water pumping, the water on the lower pond side is sucked up by the runner 13 from the draft tube 18 by rotating the main shaft 14 and sent out from the guide vane 15 and the stay vane 16 into the casing 17. It is now sent to Kamiike.

  In the water turbine 11, servo motors 22 are provided to the individual guide vanes 15 via the link mechanisms 21, and these servo motors 22 are individually driven by the guide vane angle control means 30. .

  That is, when the servo motor 22 is driven by the guide vane angle control means 30, as shown in FIG. 2, via the link member 25 connected to the drive piece 24 provided on the rotating shaft 23 of the servo motor 22. The guide vane 15 is rotated by the arm 26 fixed to the support shaft 27 of the guide vane 15.

The guide vane angle control means 30 individually controls the rotation angle of the guide vane 15.
In the present embodiment, as shown in FIG. 3, the 20 guide vanes 15 are divided into five groups, that is, the first group Gr1, the second group Gr2, the third group Gr3, the fourth group Gr4, and the fifth group Gr5. The guide vane rotation angle is individually controlled for each group.
Although not all are shown, ten stay vanes 16 in the present embodiment are provided.

The rotation angles of the groups Gr1 to Gr5 of the guide vane 15 are set to different angles according to the inflow angle distribution in the circumferential direction of the fluid flowing from the stay vane 16.
The state of FIG. 3 is when the guide vane opening degree of the 20 guide vanes 15 is 65%, and this guide vane opening degree 65% means the opening degree at the maximum efficiency point flow rate in this embodiment.
Here, the guide vane opening degree indicates the degree of the throat diameter formed between the guide vanes 15, and the maximum throat diameter is defined as 0% when the guide vane is closed so that no fluid flows. Is 100%.

The guide vane rotation angle is set to gradually increase from the first group Gr1 to the fifth group Gr5 of the guide vane 15. The difference in angle between the first group Gr1 that is the minimum rotation angle and the fifth group Gr5 that is the maximum rotation angle is set within a predetermined range. As will be described later, this angle range is set within a certain range in relation to the collision loss of the guide vanes.
Here, the rotation angle refers to an angle α around the rotation center C of the guide vane 15 based on the angle when the guide vane 15 is closed and the guide vane opening degree is set to 0%. .

FIG. 4 shows the rotation angle of the guide vane with respect to the guide vane opening.
As can be seen from the figure, when the guide vane opening is a small flow rate, specifically, when the guide vane opening is 18% or less, all the rotation angles are the same (that is, individual control is not performed). .)
When the guide vane opening is further increased (when the flow rate is increased), individual control is performed so as to gradually change the rotation angle for each group.
When the guide vane opening is 30% or more and 55% or less, the range of the rotation angle varied between the groups is set to about 5 °, and the angle range is kept constant.
When the guide vane opening exceeds 55%, the range of the rotation angle varied between the groups is gradually narrowed, and when the guide vane opening is 70% or more, all the rotation angles are made the same (ie, individual control). Do not do).

Next, the reason why the rotation angle of the guide vane is controlled according to the guide vane opening as shown in FIG. 4 will be described with reference to FIG.
FIG. 5A shows the incident angle of the fluid flowing into the guide vane 15. When the incident angle is 0 °, that is, when the fluid flow is along the guide vane, it becomes a design point, and there is no collision loss of fluid against the guide vane. The angles at which the angle of the fluid flowing into the guide vane 15 deviates on both sides from the design point (0 °) are indicated by positive and negative values, respectively.

FIG. 5B shows an example of the collision loss of the guide vane with respect to the incidence angle. As shown in the figure, the collision loss of the guide vane 15 is the smallest at the design point (0 °), and the low collision loss is maintained on both sides of the design point. Then, a predetermined angle (generally about 10 °, if the present reference embodiment 5 °) from the design point deviates sharply collision loss increases.
As can be seen from this figure, when the rotation angle α of the guide vane 15 is set so that the incidence angle is set in the low collision loss region where the collision loss does not increase suddenly, the collision loss in the guide vane 15 is determined. And the efficiency of the water turbine can be increased as much as possible. Therefore, in this reference embodiment, when the maximum efficiency point flow rate, when setting the rotation angle of the guide vanes in accordance with the circumferential velocity distribution of the fluid flowing from the stay vanes 16, not shock loss is large low collision loss region of The rotation angle of the guide vane 15 is set so that the incidence angle is set within the range.

On the other hand, the rotation angle of the guide vane 15 deviates from the design point (0 °) at a small flow rate with a small guide vane opening and at a large flow rate with a large guide vane opening. Specifically, in FIG. 5B, the incidence angle is set in a direction away from the design point on both sides.
If the rotation angle of each guide vane 15 is widened at the time of a small flow rate and a large flow rate, as shown in FIG. 5 (b), the absolute value of the incident angle of a part of the guide vane 15 becomes large, resulting in a large collision loss. Will be invited. This increases the overall loss, and the efficiency of the water turbine cannot be improved. Therefore, in this reference embodiment, as shown in FIG. 4, at the time of small flow rate and at a large flow rate, so as not to have a width incidence angle, so as not to perform the individual control of the rotation angle of the guide vanes 15 did.

According to the water wheel according to the reference embodiment has the following advantages.
Since the rotation angle of the guide vane 15 is set within the range of the low collision loss region, the guide vane collision loss is not increased in relation to the inflow angle distribution in the circumferential direction of the fluid that has passed through the stay vane 16. Since the guide vane rotation angle is set, a water turbine that is as efficient as possible can be realized.

  In particular, at the highest efficiency point flow rate, the incidence angle of the guide vane 15 is in the vicinity of the design point, so that the incidence angle of all the guide vanes 15 can be set within the low collision loss region, so that the highest efficiency can be realized. .

  In addition, when the flow rate is small and the flow rate is far from the maximum efficiency point flow rate, the individual control of the rotation angle of the guide vane 15 is not performed, so that the guide vane is set to the incident angle where the collision loss is large. Can be avoided. Thereby, a water turbine with little loss can be provided even at the time of a small flow rate and a large flow rate.

As an embodiment of the present invention based on this reference embodiment, there is a guide vane rotation angle control method shown in FIGS.
This embodiment is mainly intended to improve the efficiency at the maximum efficiency point flow rate, and can be applied when the collision loss of the guide vane 15 at a small flow rate or at a large flow rate can be determined to be smaller than the overall loss. It is.

Figure 6 is a first embodiment of a guide vane turning angle control method according to this embodiment. In this figure, the setting range of the rotation angle of each guide vane 15 is increased at a constant rate from a small flow rate (small guide vane opening degree) to a large flow rate (large guide vane opening degree).
According to this embodiment, since the setting range of the rotation angle of each guide vane 15 is small when the flow rate is small, the collision loss at the small flow rate can be reduced.
At the maximum efficiency point flow rate, the efficiency can be improved as in the case of FIG.
When the flow rate is large, the setting range of the rotation angle of each guide vane 15 becomes large, and some of the guide vanes 15 are set at an incidence angle where the collision loss is large. Such control is also useful when the loss is negligibly small compared to the loss of.
By performing the guiding vane rotation angle control as in this embodiment, the setting range of the rotation angle of each guide vane 15, it is possible to set in a geometric function of the guide vane opening, simple control program There is an advantage of becoming.

Figure 7 is a second embodiment of the guide vane turning angle control method according to this embodiment. In the figure, the setting range of the rotation angle of each guide vane 15 is made constant from a small flow rate (small guide vane opening degree) to a large flow rate (large guide vane opening degree).
Even in this embodiment , at the maximum efficiency point flow rate, the efficiency can be improved as in the case of FIG.
On the other hand, at the time of a small flow rate and a large flow rate, the setting range of the rotation angle of each guide vane 15 becomes large, and some guide vanes 15 are set at an incidence angle where the collision loss is large. Such control is also useful if the 15 collision losses are negligibly small compared to the total loss.
By controlling the guide vane rotation angle as in this embodiment, the setting range of the rotation angle of each guide vane 15 can be set with an equality function regardless of the guide vane opening, so that the control program Has the advantage of being extremely simple.

  In this embodiment, the guide vanes 15 are divided into five groups and the rotation angle is individually controlled. However, the present invention is not limited to this, and the group may be 2 or more and 4 or less, and 6 or more. It may be a group. Alternatively, all the guide vanes 15 may be individually controlled.

It is the longitudinal cross-sectional view which showed the guide vane vicinity of the water turbine concerning the reference embodiment by this invention. It is the top view which showed the opening degree control mechanism of the guide vane concerning this reference embodiment. It is the cross-sectional view which showed the state which divides a guide vane into five groups and carried out individual control. It is the figure which showed the method of carrying out the individual control of the guide vane rotation angle according to the guide vane opening degree. It is explanatory drawing for determining the setting range of a guide vane, (a) shows the definition of the angle of the fluid which flows into a guide vane, (b) shows the incident angle of the inflow fluid with respect to a guide vane, and the collision loss of a guide vane Shows the relationship. It is a diagram showing a first example of an embodiment of the present invention. It is a diagram showing a second example of an embodiment of the present invention. It is a fragmentary sectional perspective view which shows the structure of the conventional water wheel. It is sectional drawing which shows arrangement | positioning of the guide vane and the stay vane of the conventional water wheel.

11 Water wheel 12 Runner vane 13 Runner 15 Guide vane 16 Stay vane 17 Casing 30 Guide vane angle control means

Claims (4)

A plurality of runner vanes provided along the circumferential direction, a plurality of guide vanes provided on the outer peripheral side of the runner, the rotation angles of which can be individually changed, and an outer periphery of the guide vanes. In a water turbine comprising a plurality of stay vanes, and guide vane angle control means for individually controlling the rotation angle of each guide vane,
The guide vane angle of the control means, the rotation angle of each guide vane, the guide for the fluid flowing into the vane guide vane shock loss on both sides to approximately 10 ° from the design point to be the smallest design point near There rows individually controlled so as to be set within the range, at the time of small flow rate, water wheel, characterized in that narrower than the maximum efficiency point flow time setting range of the rotation angle of each guide vane. A plurality of runner vanes provided along the circumferential direction, a plurality of guide vanes provided on the outer peripheral side of the runner, the rotation angles of which can be individually changed, and an outer periphery of the guide vanes. In a water turbine comprising a plurality of stay vanes, and guide vane angle control means for individually controlling the rotation angle of each guide vane,
The guide vane angle control means has a range of about 10 ° on both sides from the design point so that the rotation angle of each guide vane is in the vicinity of the design point where the guide vane collision loss with respect to the fluid flowing into the guide vane is the smallest. A water wheel characterized by performing individual control so as to be set within the range, and narrowing the setting range of the rotation angle of each guide vane at a large flow rate than at a maximum efficiency point flow rate. A plurality of runner vanes provided along the circumferential direction, a plurality of guide vanes provided on the outer peripheral side of the runner, the rotation angles of which can be individually changed, and an outer periphery of the guide vanes. In a method of controlling a water turbine equipped with a plurality of stay vanes,
Individually, the rotation angle of each guide vane is set within a range of about 10 ° on both sides from the design point so that the guide vane collision loss with respect to the fluid flowing into the guide vane is near the design point. control stomach line,
A method for controlling a water turbine, characterized in that, when the flow rate is small, the setting range of the rotation angle of each guide vane is narrower than that at the maximum efficiency point flow rate . A plurality of runner vanes provided along the circumferential direction, a plurality of guide vanes provided on the outer peripheral side of the runner, the rotation angles of which can be individually changed, and an outer periphery of the guide vanes. In a method of controlling a water turbine equipped with a plurality of stay vanes,
Individually, the rotation angle of each guide vane is set within a range of about 10 ° on both sides from the design point so that the guide vane collision loss with respect to the fluid flowing into the guide vane is near the design point. control stomach line,
A method for controlling a water turbine, characterized in that, when the flow rate is large, the setting range of the rotation angle of each guide vane is narrower than when the maximum efficiency point flow rate.

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