JP2014227916A - Hydraulic machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic machinery capable of restricting water flow flowing between stay vanes from showing a flow velocity distribution deflected to the downstream side, reducing loss and improving its efficiency.SOLUTION: A hydraulic machinery 1 constructed in accordance with the preferred embodiment of the present invention comprises: a spiral casing 4 into which water flows from an upper pond 2; and a plurality of stages 5 arranged to be spaced apart at the inner circumference side of the casing 4. The inner circumferential sides of guide vanes 9 are provided with runners 11 rotationally driven by water flow got from the guide vanes 9. A commutation body 20 is installed between a pair of stay vanes 5 adjacent to each other. The commutation body 20 extends from the side surface of one corresponding stay vane 5 to the side surface of the other corresponding stay vane 5 and further extends from the upstream side to the downstream side.

Description

  Embodiments of the present invention relate to a hydraulic machine.

  Conventionally, a Francis type turbine is known as an example of a hydraulic machine. During the turbine operation of the Francis turbine, water flows from the upper pond through the hydraulic pipe into the spiral casing, and the water flowing into the casing passes through the stationary blade row flow path constituted by the stay vanes and guide vanes. Flow into the runner. The runner is rotationally driven by the water flowing into the runner. When the runner is driven to rotate, the generator motor connected to the runner via the main shaft is driven to generate power. The water that rotationally drives the runner flows out from the runner to the lower pond through the suction pipe and the discharge channel. During such a water turbine operation, the amount of power generated is changed by adjusting the amount of water flowing into the runner by changing the opening of the guide vane.

  On the other hand, during the pump operation (pumping operation), the runner is rotationally driven by the generator motor and rotates in the opposite direction to that during the water turbine operation. As a result, the water in the lower pond flows into the runner through the discharge channel and the suction pipe. The water that has flowed into the runner flows from the runner to the casing through the stationary blade cascade formed by the guide vanes and the stay vanes, and is discharged to the upper pond through the hydraulic pipe. At this time, the opening degree of the guide vane is changed so as to obtain an appropriate pumping amount according to the pump head.

  A specific configuration of the Francis turbine will be described below with reference to the drawings.

  FIG. 8 shows a meridional section view from the bell mouth type casing 41 to the entrance of the runner 47. As shown in FIG. 8, the stay vane 42 is interposed between the upper wall 43 and the lower wall 44, and the upper wall 43 and the lower wall 44 are located downstream (on the guide vane 45 side). It is formed so as to be squeezed into a trumpet shape. Accordingly, the flow width of the water flow flowing from the casing 41 into the stay vane 42 (the width in the height direction shown in FIG. 8) gradually decreases toward the downstream side, and the water flow is accelerated.

  FIG. 9 shows a horizontal cross-sectional view of a stationary blade row channel 46 constituted by stay vanes 42 and guide vanes 45. As shown in FIG. 9, a plurality of stay vanes 42 are arranged in the circumferential direction with a predetermined interval. On the inner peripheral side of these stay vanes 42, a plurality of guide vanes 45 are arranged in the circumferential direction at a predetermined interval.

  The stay vane 42 is for guiding water flowing from the casing 41 to the guide vane 45. That is, as shown in FIG. 9, the angle θ2 formed by the velocity vector V2 of the water flow flowing out from the stay vane 42 is made larger than the angle θ1 formed by the velocity vector V1 of the water flow flowing into the stay vane 42, and the stay vane 42 is The flowing water is guided to the guide vane 45. Further, the stay vane 42 is formed so that the flow path area between the adjacent stay vanes 42 is reduced toward the downstream side. As a result, the water flow between the stay vanes 42 is increased.

  Each guide vane 45 is rotatable about a guide vane shaft center point 45a. Thus, the angle of the guide vane 45 (hereinafter referred to as “guide vane opening degree”) can be changed, and the area of the flow path formed between the adjacent guide vanes 45 can be changed. For this reason, the guide vane 45 can change the flow rate of the water flowing into the runner 47, whereby the power generation amount in the generator motor connected to the runner 47 can be adjusted. The guide vane axis center point 45a of each guide vane 45 is arranged on the guide vane pitch circle 45b.

  In such a Francis type turbine, in general, the shape of the runner blades 47a of the stay vane 42, the guide vane 45, and the runner 47 is designed to follow the water flow during operation, but the flow may be uneven in the flow path. is there. Various proposals have been made to improve such a flow bias (see, for example, Patent Documents 1 to 4).

  Among these, Patent Documents 1 to 3 disclose a Francis type turbine in which a rectifier is provided between adjacent runner blades in a runner. Further, Patent Document 4 discloses a water wheel provided with a rectifier for relaxing the vertical inclination of the water flow flowing into the stay vanes.

JP 2008-175169 A JP 2007-32458 A JP 2005-133698 A Japanese Patent No. 4786235

  By the way, as shown in FIG. 10, in the case of a bell mouth type flow path, the water pressure pipe 48 provided on the upstream side of the casing 41 is inclined. And the inclined part 48a of this hydraulic pipe 48 is connected with the casing 41 via the horizontal part 48b. Thus, the water flow flowing into the casing 41 has a flow velocity distribution such that the upper side becomes slower and the lower side becomes faster. For this reason, the water flow in the casing 41 tends to be biased downward. As described above, since the water flow flowing from the casing 41 into the stay vane 42 is accelerated, when such a biased water flow flows into the stay vane 42, the bias is amplified. For this reason, the water flow flowing between the stay vanes 42 has a flow velocity distribution in which the water flow is biased downward. As a result, a secondary flow loss may occur and the turbine efficiency may be reduced. This can exist also in the water wheel shown in patent documents 1 thru / or 4 mentioned above.

  The present invention has been made in consideration of such points, and it is possible to suppress the flow of water flowing between the stay vanes from having a flow velocity distribution that is biased downward, thereby reducing the loss and improving the efficiency. The purpose is to provide a hydraulic machine.

  The hydraulic machine according to the embodiment includes a spiral casing into which water flows from the upper pond, and a plurality of stay vanes arranged at intervals on the inner peripheral side of the casing. The stay vanes are configured to direct water flow from the casing. A plurality of guide vanes are provided on the inner peripheral side of the stay vanes. The guide vanes are arranged at intervals in the circumferential direction, and are configured to guide the water flow from the stay vanes and adjust the flow rate. A runner that is rotationally driven by a water flow from the guide vane is provided on the inner peripheral side of the guide vane. A rectifier is provided between a pair of adjacent stay vanes. The rectifying body extends from the side surface of the corresponding one of the stay vanes to the side surface of the corresponding other stay vane and extends from the upstream side toward the downstream side.

FIG. 1 is a diagram showing an overall configuration of a hydraulic machine in the present embodiment. FIG. 2 is a horizontal sectional view showing a rectifier in the hydraulic machine of FIG. FIG. 3 is a meridional cross-sectional view showing a rectifier in the hydraulic machine of FIG. 1. FIG. 4 is a diagram showing a flow velocity distribution of a water flow flowing between the stay vanes in the hydraulic machine of FIG. FIG. 5 is a diagram illustrating the relationship between the dimensionless amount of the radial length of the rectifier and various losses in the hydraulic machine of FIG. 1. FIG. 6 is a diagram illustrating the relationship between the guide vane opening degree and the stationary blade row flow path loss in the hydraulic machine of FIG. 1. FIG. 7 is a diagram showing the relationship between the guide vane opening degree and the turbine efficiency in the hydraulic machine of FIG. FIG. 8 is a meridional section view showing a configuration from a casing to a guide vane in a conventional hydraulic machine. FIG. 9 is a horizontal sectional view showing a stay vane and a guide vane in a conventional hydraulic machine. FIG. 10 is a diagram showing a flow velocity distribution of a water flow flowing from a hydraulic pipe to a guide vane in a conventional hydraulic machine.

  A hydraulic machine according to an embodiment of the present invention will be described with reference to FIGS.

  First, a Francis turbine as an example of a hydraulic machine will be described with reference to FIG.

  As shown in FIG. 1, the Francis turbine 1 is provided on a spiral casing 4 into which water flows from the upper pond 2 through the hydraulic pipe 3 during the water turbine operation, and on the inner peripheral side of the casing 4. And a plurality of stay vanes 5 for guiding the water flow to guide vanes 9 to be described later. Of these, the hydraulic pipe 3 has an inclined portion 3a provided on the upper pond 2 side and a horizontal portion 3b provided on the downstream side of the inclined portion 3a. An inlet valve 6 is provided in the horizontal portion 3b.

  As shown in FIG. 2, the plurality of stay vanes 5 are arranged at intervals in the circumferential direction. A flow path is formed between adjacent stay vanes 5, and water flowing from the casing 4 flows through each flow path.

  As shown in FIG. 3, the stay vane 5 is interposed between the upper wall 7 and the lower wall 8. That is, the upper edge portion of the stay vane 5 is fixed to the upper wall 7, and the lower edge portion of the stay vane 5 is fixed to the lower wall 8. These upper wall 7 and lower wall 8 are formed so as to be squeezed in a trumpet shape toward the downstream side (guide vane 9 side). As a result, the flow width of the water flow flowing into the stay vanes 5 (see FIG. 8) gradually decreases toward the downstream side, and the water flow speeds up.

  As shown in FIG. 1, a plurality of guide vanes 9 are provided on the inner peripheral side of the stay vane 5. The guide vane 9 and the above-described stay vane 5 constitute a stationary blade row channel 10.

  As shown in FIG. 2, the plurality of guide vanes 9 are arranged at intervals in the circumferential direction. A flow path is formed between the guide vanes 9 adjacent to each other, and water flowing from the stay vane 5 flows through each flow path.

  The guide vane 9 is for guiding the water flow from the stay vane 5 to the runner 11. Further, the guide vane 9 can adjust the flow rate of water. That is, the guide vane 9 is configured to be rotatable around a guide vane shaft center point 9a disposed on the guide vane pitch circle 9b, and the angle (guide vane opening degree) can be changed. Thus, the flow area of the flow path formed between the adjacent guide vanes 9 can be changed, and the flow rate of water flowing from the casing 4 into the runner 11 can be adjusted during the water turbine operation. In this case, the amount of power generated by the generator motor 13 described later can be changed. During the pump operation, the guide vane 9 can change the amount of pumped water.

  As shown in FIG. 1, a runner 11 is provided on the inner peripheral side of the guide vane 9. The runner 11 is configured to be rotatable about the rotation axis X and is driven to rotate by a water flow from the casing 4.

  A generator motor 13 is connected to the runner 11 via a main shaft 12. The generator motor 13 is configured to generate power during the operation of the water turbine. A suction pipe 14 is provided on the downstream side of the runner 11 when the water turbine is operated. The suction pipe 14 is connected to a lower pond (not shown) via a water discharge channel 15 so that water obtained by rotationally driving the runner 11 is discharged to the lower pond.

  During pump operation (during pumping operation), the generator motor 13 rotates the runner 11 to suck up the water in the suction pipe 14 and pump it up. The water sucked up by the runner 11 flows into the casing 4 through the guide vane 9 and the stay vane 5, and is discharged from the casing 4 through the hydraulic pipe 3 to the upper pond 2. The guide vane 9 and the stay vane 5 guide the water flowing from the runner 11 to the casing 4. At this time, the opening degree of the guide vane 9 is changed so as to obtain an appropriate pumping amount according to the pump head.

  Next, the rectifier 20 will be described.

  As shown in FIG. 2, the rectifying body 20 is provided between a pair of adjacent stay vanes 5. From the corresponding side surface (blade pressure surface 5 a) of one stay vane 5, the side surface ( It is formed so as to extend to the blade suction surface 5b). The rectifying body 20 extends from the upstream side toward the downstream side. More specifically, the rectifier 20 is formed to extend in the radial direction or the horizontal direction. The flow path formed between the corresponding pair of stay vanes 5 is divided in the vertical direction by such a rectifier 20 so that water flows on the upper side and the lower side of the rectifier 20. Note that the rectifier 20 is preferably formed in a flat shape.

  As shown in FIG. 2, the downstream edge 20 a of the rectifying body 20 extends in the circumferential direction from the downstream end (exit end) 5 c of the corresponding one of the stay vanes 5 toward the downstream end 5 c of the other stay vane 5. Is formed. In other words, the downstream edge 20 a of the rectifier 20 is formed to have the same curvature as the stay vane outlet end diameter 30. Here, the stay vane outlet end diameter 30 is a circle in contact with the downstream end 5 c of each stay vane 5, and means the diameter of a circle centered on the rotation axis center of the runner 11. Moreover, the wording of the same is not restricted to a strict meaning, but is used as including a range where a similar function can be expected.

  On the other hand, the upstream edge 20b of the rectifying body 20 is disposed downstream of an arc extending in the circumferential direction from the upstream end (inlet end) 5d of the corresponding one of the stay vanes 5 toward the upstream end 5d of the other stay vane 5. Yes. In other words, the upstream edge 20 b of the rectifier 20 is formed to have a smaller curvature than the stay vane inlet end diameter 31. Here, the stay vane inlet end diameter 31 is a circle in contact with the upstream end 5 d of each stay vane 5 and means the diameter of a circle centered on the rotation axis center of the runner 11.

  Further, as shown in FIGS. 2 and 3, the length of the rectifying body 20 in the radial direction is preferably shorter than the length of the stay vane in the radial direction. The radial direction means a direction perpendicular to the rotation axis X from the rotation axis center of the runner 11.

More specifically, when the radial length of the rectifying body 20 is L1, and the radial length L0 of the stay vane 5, the dimensionless amount x of the radial length of the rectifying body 20 is
x = L1 / L0
This dimensionless quantity x is expressed as
1/8 ≦ x ≦ 3/8
It is preferable that

  In addition, as shown in FIG. 3, the rectifying body 20 is preferably arranged in the center in the height direction of the stay vane 5 from the upstream edge 20b to the downstream edge 20a. More specifically, it is preferable that the distance between the rectifying body 20 and the upper wall 7 is equal to the distance between the rectifying body 20 and the lower wall 8.

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

  When the turbine operation is performed in the Francis turbine 1 according to the present embodiment, water flows into the casing 4 from the upper pond 2 through the hydraulic pipe 3. The water flowing into the casing 4 flows from the casing 4 through the stay vane 5 and the guide vane 9 into the runner 11. The runner 11 is rotationally driven by the water flowing into the runner 11. As a result, the generator motor 13 connected to the runner 11 is driven to generate power. The water flowing into the runner 11 is discharged from the runner 11 through the suction pipe 14 and the water discharge channel 15 to the lower pond.

  During the water turbine operation, water from the upper pond 2 flows through the inclined portion 3 a of the water pressure pipe 3. As a result, the water flowing into the casing 4 tends to flow downward (see FIG. 10). However, such a downwardly biased water flow is rectified by the rectifier 20 when it flows into the stay vane 5.

  That is, when water flows through the inclined portion 3 a of the hydraulic pipe 3, the water flow in the casing 4 has a downward speed component in addition to the horizontal speed component toward the downstream side (the guide vane 9 side). ing. Thereby, the water flow in the casing 4 becomes a flow biased downward. However, such downward flow velocity component is forced by the rectifier 20 in the horizontal direction toward the downstream side. Thereby, the flow velocity of the water flowing through the flow path above the rectifier 20 among the flow paths formed between the pair of stay vanes 5 can be increased. For this reason, as shown in FIG. 4, in the flow path between the stay vanes 5, it is possible to reduce the deviation of the flow velocity distribution to the lower side and level the height direction.

  Next, the effect | action of the rectifier 20 is demonstrated using FIG. 5 thru | or FIG.

  FIG. 5 shows the relationship between the dimensionless amount x of the radial length of the rectifier 20 and various losses in the flow path between the stay vanes 5. As described above, by providing the rectifying body 20, it is possible to suppress the water flow flowing between the stay vanes 5 from having a flow velocity distribution that is biased downward, and to level the height. For this reason, as shown in FIG. 5, the secondary flow loss is reduced in the stay vanes 5. 5 that the secondary flow loss is further reduced by increasing the radial length of the rectifier 20.

  On the other hand, increasing the radial length of the rectifier 20 can increase the friction loss. However, as described above, the secondary flow loss is reduced. For this reason, as also shown in FIG. 5, the total loss, which is the sum of the secondary flow loss and the friction loss, can be reduced. More specifically, in the predetermined range of the dimensionless amount x of the length in the radial direction of the rectifying body 20, the total loss is reduced more than the total loss when the rectifying body 20 is not provided (x = 0). be able to. For example, when the dimensionless amount x of the radial length of the rectifier 20 is 1/8 or more and 3/8 or less, the total loss is 1/2 or less of the total loss when the rectifier 20 is not provided. Become.

  FIG. 6 shows the relationship between the guide vane opening and the stationary blade row flow path loss (ΔHsg / H). Here, the relationship in the case where the rectifier 20 is provided so that the total loss shown in FIG. 5 is ½ of the total loss when the rectifier 20 is not provided is shown. As shown in FIG. 6, the loss in the stationary blade cascade channel 10 provided with the rectifier 20 is not related to the opening degree of the guide vane, and the conventional stationary blade cascade flow without the rectifier 20 is provided. It can be seen that the loss is reduced more than the loss in the road 10. The stationary blade row flow path loss is a loss in the stationary blade row flow path 10 constituted by the stay vanes 5 and the guide vanes 9, and here, the total loss in the flow path between the stay vanes 5 shown in FIG. And the total loss in the flow path between the guide vanes 9 is shown. ΔHsg indicates a loss head in the flow path between the stay vanes 5 and the flow path between the guide vanes 9, and H indicates an effective head.

  FIG. 7 shows the relationship between the guide vane opening and the turbine efficiency (ηt). Here, the relationship in the case where the rectifier 20 is provided is such that the total loss shown in FIG. 5 is ½ of the total loss when the rectifier 20 is not provided. As shown in FIG. 7, the turbine efficiency of the Francis turbine 1 provided with the rectifier 20 is not related to the opening degree of the guide vane, and the turbine efficiency of the conventional Francis turbine 1 provided with no rectifier 20 is the same. It can be seen that the efficiency is higher than the turbine efficiency.

  As described above, according to the present embodiment, since the rectifying body 20 is provided between the pair of adjacent stay vanes 5, the water flow in the casing 4 has a flow velocity distribution that is biased downward. Even in such a case, it is possible to suppress the flow of water flowing between the stay vanes 5 from having a flow velocity distribution that is biased downward. For this reason, the secondary flow loss generated in the water flow flowing between the stay vanes 5 can be reduced, and the turbine efficiency of the Francis turbine 1 can be improved. At this time, it is possible to suppress the water flow flowing into the guide vane 9 and the runner 11 from having a flow velocity distribution biased downward. In this respect as well, it can contribute to improving the turbine efficiency.

  Further, according to the present embodiment, the downstream edge 20a of the rectifier 20 is formed to extend in the circumferential direction from the downstream end 5c of the corresponding one of the stay vanes 5 toward the downstream end 5c of the other stay vane 5. ing. Accordingly, it is possible to suppress the water flow from having a flow velocity distribution biased downward at the outlet of the flow path between the stay vanes 5. For this reason, it can further suppress that the water flow which flows in into the guide vane 9 and the runner 11 has the flow velocity distribution biased downward.

  Further, as in the present embodiment, when the dimensionless amount x of the radial length of the rectifying body 20 is set to 1/8 or more and 3/8 or less, the secondary flow loss and friction in the flow path between the stay vanes 5 The total loss including the total loss can be reduced to ½ or less of the total loss when the rectifier 20 is not provided. That is, although the friction loss can be caused by providing the rectifying body 20, the secondary flow loss can be greatly reduced to such an extent that the friction loss can be absorbed. For this reason, the total loss in the flow path between the stay vanes 5 can be reliably reduced.

  Moreover, according to this Embodiment, the rectifier 20 is formed in flat shape. Thereby, it is possible to further suppress the water flow flowing between the stay vanes 5 from having a flow velocity distribution biased downward.

  Furthermore, according to the present embodiment, the rectifying body 20 is arranged in the center in the height direction of the stay vane 5. Thereby, it is possible to further suppress the water flow flowing between the stay vanes 5 from having a flow velocity distribution biased downward.

  The embodiment of the present invention has been described in detail above, but the hydraulic machine according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. Is possible. In the above-described embodiment, the example in which the hydraulic machine according to the present invention is applied to the Francis type turbine has been described. However, the present invention is not limited to this, and the hydraulic machine according to the present invention is applied to a turbine other than the Francis type turbine. You can also

  In the present embodiment described above, the downstream edge 20a of the rectifying body 20 extends in the circumferential direction from the downstream end 5c of the corresponding one of the stay vanes 5 toward the downstream end 5c of the other stay vane 5. The example which is formed has been described. However, the present invention is not limited to this, and the position of the downstream edge 20a of the rectifying body 20 is arbitrary as long as it is possible to suppress the flow of water flowing between the stay vanes 5 from having a flow velocity distribution biased downward. be able to.

DESCRIPTION OF SYMBOLS 1 Francis type turbine 2 Upper pond 3 Hydraulic pipe 3a Inclined part 3b Horizontal part 4 Casing 5 Stay vane 5a Blade pressure surface 5b Blade negative pressure surface 5c Downstream end 5d Upstream end 6 Inlet valve 7 Upper wall 8 Lower wall 9 Guide vane 10 Stationary blade row Flow path 11 Runner 12 Main shaft 13 Generator motor 14 Suction pipe 15 Water discharge path 20 Rectifier 20a Downstream edge 20b Upstream edge 30 Stay vane outlet end diameter 31 Stay vane inlet end diameter

Claims (5)

A spiral casing into which water flows from the upper pond;
A plurality of stay vanes arranged at intervals on the inner peripheral side of the casing and guiding the water flow from the casing;
A plurality of guide vanes that are arranged at an interval on the inner peripheral side of the stay vane, guide the water flow from the stay vane and adjust the flow rate;
A runner provided on the inner peripheral side of the guide vane and driven to rotate by a water flow from the guide vane,
A rectifier is provided between a pair of adjacent stay vanes,
The rectifying body extends from the side surface of one corresponding stay vane to the side surface of the other corresponding stay vane and extends from the upstream side toward the downstream side.   The downstream edge of the rectifying body is formed so as to extend in a circumferential direction from the downstream end of the corresponding one of the stay vanes toward the downstream end of the other corresponding stay vane. Listed hydraulic machine. The dimensionless amount x of the radial length of the rectifying body obtained by making the radial length L1 of the rectifying body dimensionless with the radial length L0 of the stay vane is:
1/8 ≦ x ≦ 3/8, x = L1 / L0
The hydraulic machine according to claim 1 or 2, wherein:   The hydraulic machine according to claim 1, wherein the rectifier is formed in a flat shape.   The hydraulic machine according to any one of claims 1 to 4, wherein the rectifying body is disposed in the center in the height direction of the stay vanes.