JP2019199801A - Runner vane and axial flow hydraulic machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a runner vane and an axial flow hydraulic machine for suppressing leakage flow and improving the performance of the hydraulic machine. According to an embodiment of the present invention, a runner vane is provided on the outer periphery of a runner boss, the outer peripheral surface of the runner vane facing a discharge ring surrounding the outer periphery of the runner vane is provided with a recess. With the above configuration, the water flowing between the discharge ring and the runner vanes is guided to the pressure surface of the runner vanes through the recesses and flows together with the main flow. [Selection diagram] Fig. 3

Description

  Embodiments of the present invention relate to runner vanes and axial flow hydraulic machines.

In the conventional axial flow hydraulic machine, a gap is provided between the runner vane and the discharge ring to avoid mutual contact.

JP-A-60-153478

However, during the operation of the axial flow hydraulic machine, there is a leakage flow that does not contribute to the rotation of the runner vane and flows from the pressure surface side to the negative pressure surface side through this gap. This leakage flow tends to be turbulent on the runner vane outlet side, and causes a reduction in performance of the axial hydraulic machine such as cavitation.

Therefore, the problem to be solved by the present invention is to provide a runner vane and an axial flow hydraulic machine that suppress the leakage flow and improve the performance of the hydraulic machine.

In order to solve the above-described problem, according to the runner vane of the embodiment, the runner vane is provided on the outer periphery of the runner boss, and a recess is provided on the outer peripheral surface of the runner vane facing the discharge ring surrounding the outer periphery of the runner vane.

It is a schematic diagram of the axial-flow hydraulic machine which concerns on any one of 1st to 3rd embodiment. It is a perspective view which shows the runner of the axial flow hydraulic machine containing the runner vane which concerns on 1st embodiment. It is an enlarged view of the runner vane concerning a first embodiment. It is an enlarged view of the runner vane which concerns on 2nd embodiment. It is an enlarged view of the runner vane which concerns on the modification of 2nd embodiment. It is a perspective view which shows the runner of the axial flow hydraulic machine containing the runner vane which concerns on 3rd embodiment.

First to third embodiments of the present invention will be described. In each embodiment, a recess is provided on the outer peripheral surface of a runner vane, which will be described later, thereby suppressing leakage flow flowing from the pressure surface side of the runner vane to the suction surface side. In each embodiment, there is a difference in the presence or absence of a mechanism for flowing water into the recess and a mechanism for discharging water that flows into the recess. Hereinafter, each embodiment will be described in detail.

The structure of the axial flow hydraulic machine common to each embodiment is demonstrated using FIG. FIG.
It is a schematic diagram of the axial-flow hydraulic machine which concerns on any one of 1st to 3rd embodiment. Here, a Kaplan turbine is illustrated and described as an axial hydraulic machine, but the axial hydraulic machine is not limited to this,
For example, a propeller turbine or a valve turbine may be used. Further, in the following description, the water flow in the water turbine operation is exemplified, and the upstream side of the water in the water turbine operation is simply referred to as the upstream side, and the downstream side of the water in the water turbine operation is simply referred to as the downstream side.

As shown in FIG. 1, the axial hydraulic machine 1 includes a casing 2 into which water flows from an upper pond (not shown), a stay vane 3, a guide vane 4, a rotating main shaft 5, a generator 6, The suction pipe 7, the runner 10, and the discharge ring 30 are configured.

The stay vane 3 is disposed on the inner peripheral side of the casing 2, and the runner 2 extends from the casing 2.
A flow path to zero is formed. The guide vane 4 is arranged on the inner peripheral side of the stay vane 3 and adjusts the flow rate of water flowing from the casing 2 into the runner 10 by changing the opening degree of the guide vane 4.

The runner 10 includes a runner boss 11 and a runner vane 20, and is disposed on the inner peripheral side and the downstream side of the guide vane 4. The runner boss 11 is connected to the generator 6 via the rotary main shaft 5. The runner vanes 20 are provided radially on the outer periphery of the runner boss 11, and the outer periphery thereof is surrounded by the discharge ring 30.

Water that has flowed from the casing 2 through the stay vane 3 and the guide vane 4 into the runner 10 sequentially passes through a pressure surface 20a of the runner vane 20 described later, and rotates the runner vane 20 and the runner boss 11 (that is, the runner 10). As the runner boss 11 rotates,
The generator 6 connected to the runner boss 11 via the rotation main shaft 5 is rotationally driven to generate power. A suction pipe 7 is provided on the downstream side of the runner 10, and water flowing out of the runner 10 is discharged to the lower pond (not shown) through the suction pipe 7.

On the other hand, a part of the water that has flowed into the runner 10 from the upstream side does not pass through the pressure surface 20a but flows between the outer peripheral surface 20c of the runner vane 20 and the discharge ring 30 described later.

(First embodiment)
The runner vane and the axial flow hydraulic machine according to the first embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a perspective view showing a runner of the axial flow hydraulic machine including the runner vane according to the first embodiment, and FIG. 3 is an enlarged view of the runner vane according to the first embodiment. FIG.
The arrow passing through the pressure surface 20a is an example of the main flow, the arrow passing through the outer peripheral surface 20c is an example of the leakage flow, and the arrow toward the pressure surface 20a after flowing into the recess 21 is the water flow flowing into the recess 21 Each example is shown. Further, the location indicated by the dots in FIG. 3 is the bottom surface of the recess 21.

The runner vane 20 in the first embodiment is characterized in that a concave portion 21 is provided on the outer peripheral surface 20 c facing the inner peripheral surface of the discharge ring 30. As shown in FIG. 3, the concave portion 21 is recessed from the outer peripheral surface 20 c toward the central axis X, and the negative pressure surface 20 b side (pressure surface 20
The depth becomes shallower from the back side of a) toward the pressure surface 20a side. That is, the negative pressure surface 20b is recessed more deeply.

By providing the recess 21 in the runner vane 20, the water flowing into the gap between the runner vane 20 and the discharge ring 30 from the upstream side is once blocked by the end face of the recess 21 as shown in FIG. 20a. At this time, since the depth of the recess of the concave portion 21 becomes shallower from the negative pressure surface 20b side toward the pressure surface 20a side, the water that has flowed in is more smoothly guided to the pressure surface 20a and downstream along the pressure surface 20a. Flows to the side. That is, the recess 21
The water led to the pressure surface 20a from the upstream contributes to the rotational drive of the generator 6 together with the main flow of water flowing into the runner 10 from the upstream side.

According to the first embodiment described above, the pressure surface 2 is used to block the water flowing into the recess 21.
The leakage flow that flows from 0a to the suction surface 20b can be suppressed. Furthermore, since the leakage flow that has flowed into the recess 21 can be guided to the pressure surface 20a to be a flow component that contributes to power generation, not only the leakage flow can be suppressed, but also the performance of the hydraulic machine can be improved.

The recess 21 is preferably provided at least on the upstream side of the outer peripheral surface 20c (upstream side of the runner vane 20). This is because the pressure difference between the pressure surface 20a side and the negative pressure surface 20b side on the upstream side of the runner vane 20 is larger than the pressure difference on the downstream side of the runner vane 20, and a leak flow is particularly likely to occur on the upstream side. However, the number and arrangement of the recesses 21 are not limited. For example, a plurality of the recesses 21 may be provided from the upstream side to the downstream side of the outer peripheral surface 20c.

Moreover, in this embodiment, as a shape of the recessed part 21, it is dented from the outer peripheral surface 20c to the center axis X side, and the case where the depth becomes shallow as it goes to the pressure surface 20a side from the negative pressure surface 20b side is illustrated. However, the shape of the concave portion 21 may be any structure as long as the inflowing water flows out to the pressure surface 20a and can flow along with the main flow. For example, the depth of the recess 21 may be uniform, and the bottom surface thereof may be inclined from the suction surface 20b side to the pressure surface 20a side, or the bottom surface of the recess 21 may be a gently curved surface.

(Second embodiment)
A runner vane and an axial flow hydraulic machine according to the second embodiment will be described with reference to FIG. FIG. 4 is an enlarged view of a runner vane according to the second embodiment. In the following, different parts from the first embodiment will be described, and other parts will be the same as the first embodiment,
The description is omitted here.

The runner vane 20 according to the second embodiment is characterized in that, in addition to the recesses 21, fins 22 that guide water that has flowed into the gaps between the runner vanes 20 and the discharge ring 30 to the recesses 21 are provided. Other configurations, for example, the shape and installation position of the recess 21 are the same as those in the first embodiment.

The fin 22 is integrally formed with the runner vane 20 in the vicinity of the recess 21 and is inclined from the upstream side to the recess 21 side from the recess 21. That is, the fin 22 protrudes upstream from the recess 21. Therefore, the water flowing into the gap between the runner vane 20 and the discharge ring 30 is guided along the fins 22 to the recess 21.

According to the second embodiment described above, by providing the fins 22, not only the same effects as in the first embodiment can be obtained, but also water flowing into the gap between the runner vane 20 and the discharge ring 30 can be finned. Therefore, the leakage flow that flows from the pressure surface 20a side to the negative pressure surface 20b side can be more efficiently suppressed.

The fins 22 may have any shape that can guide water to the recess 21, and may protrude in the rotation direction of the runner 10, for example.

As a modification of the second embodiment, as shown in FIG.
The extension member 25 including 2 may be constituted by another member and joined to a general runner vane,
As a configuration different from that in FIG.
That is, you may join to the runner vane 20) in 1st embodiment. By adopting such a configuration, it is possible to obtain the same effect as that of the second embodiment by a method that is cheaper than a method of newly manufacturing a runner vane.

(Third embodiment)
A runner vane and an axial flow hydraulic machine according to a third embodiment will be described with reference to FIG. FIG. 6 is a perspective view showing a runner of an axial flow hydraulic machine including a runner vane according to the third embodiment. In the following, different parts from the first and second embodiments and their modifications will be described, and the other parts will be described as being the same as those of the first and second embodiments and their modifications. Is omitted.

The runner vane 20 in the third embodiment is characterized in that, in addition to the recess 21, a drainage flow path 23 is provided for allowing the water flowing into the recess 21 to flow out from the recess 21 to the downstream side of the negative pressure surface 20 b. Other configurations, for example, the shape and installation position of the recess 21 are the same as those in the first and second embodiments and the modifications thereof.

The drainage flow passage 23 penetrates through the inside of one runner vane 20 and communicates an inlet 23 a formed in the recess 21 and an outlet 23 b formed in the negative pressure surface 20 b on the downstream side of the recess 21. That is, the drainage channel 23 is a channel that connects the inlet 23a and the outlet 23b. Entrance 2
Since there is a pressure difference between the 3a side and the outlet 23b side, the water that has flowed into the gap between the runner vane 20 and the discharge ring 30 is sucked into the recess 21, and a part of the water flows into the drainage channel 23.
It flows out from the exit 23b. On the other hand, water that has flowed into the recess 21 but does not pass through the drainage channel 23 is guided to the pressure surface 20a through the recess 21 and contributes to the rotational drive of the generator 6 together with the mainstream.

According to the third embodiment described above, by providing the drainage channel 23, not only the same effect as in the first embodiment can be obtained, but also the pressure difference between the inlet 23a and the outlet 23b is utilized. It is possible to induce the inflow of water into the recess 21 and more efficiently suppress the leakage flow flowing from the pressure surface 20a side to the negative pressure surface 20b side.

In the present embodiment, the outlet 23b is preferably located in the vicinity of the outlet of the runner vane 20. Since the outlet 23b is located in the vicinity of the outlet of the runner vane 20, in addition to the effects of the above-described embodiment, separation of a flow that generally occurs in the vicinity of the outlet of the runner vane can be suppressed.

1, 2, and 6, the case where all the runner vanes constituting the runner 10 are runner vanes 20 is illustrated. However, when the runner vanes 20 are applied to an axial flow hydraulic machine, the number of runner vanes 20 is limited. The runner vane 20 may be at least one runner vane. This applies similarly to other embodiments of the present invention.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1. Axial flow hydraulic machine, 2. Casing, 3. Stay vanes, 4. Guide vanes, 5. 5. Spindle, Generator, 7; 9. suction tube; Lanna, 11. Lanna boss, 20. Lanna Vane, 20a. Pressure surface, 20b. Suction surface, 20c. Outer peripheral surface, 21. Recess, 22. Fins, 23
. Drainage channel, 23a. Inlet, 23b. Exit, 30. Discharge ring

Claims (7)

A runner vane provided on the outer periphery of the runner boss,
A runner vane having a recess on the outer peripheral surface of the runner vane facing the discharge ring surrounding the outer periphery of the runner vane. 2. The runner vane according to claim 1, wherein the recess is provided on an upstream side of the outer peripheral surface during a water turbine operation. 3. The runner vane according to claim 1, wherein a depth of the concave portion decreases from the suction surface side toward the pressure surface side. 4. The runner vane according to any one of claims 1 to 3, further comprising a fin that is inclined toward the recess from an upstream side with respect to the recess and guides the water flowing between the discharge ring and the outer peripheral surface to the recess. The runner vane according to claim 4, wherein a portion including the recess and the fin is formed of a separate member. 6. The runner vane according to claim 1, wherein the runner vane is provided in the runner vane and has a drainage channel that discharges water from the concave portion to the downstream side of the suction surface. A runner having a runner boss coupled to a rotating shaft and a runner vane according to claims 1 to 6;
A discharge ring surrounding the outer periphery of the runner vane;
Axial flow hydraulic machine equipped with.

Images