CN108131232B - hydraulic machine - Google Patents

Abstract

The invention provides a hydraulic machine, which can inhibit the generation of horseshoe-shaped vortex generated around a guide vane and reduce loss. A Francis-type water pump turbine (1) as a hydraulic machine is a hydraulic machine in which a flow path (14) is rotated by water flowing from a fixed blade (13) to the flow path (14) through a guide blade (12), wherein an upper cover (18U) is disposed above the fixed blade (13) and the guide blade (12), and a lower cover (18D) is disposed below the fixed blade and the guide blade. Then, a suction mechanism (30) capable of sucking water flowing in at least one of the upper shroud (18U) side region and the lower shroud (18D) side region between the fixed blade (13) and the guide blade (12) is provided.

Description

Hydraulic machine

Technical Field

Embodiments of the present invention relate to a hydraulic machine.

Background

As hydraulic machines, for example, francis type hydraulic turbines and francis type pump turbines are known. Fig. 12 is a plan view of a stationary blade row flow path formed by a guide vane 120 and a stator vane 130 of a general francis type water turbine pump. The guide vanes 120 are arranged in plurality at intervals in the circumferential direction so as to surround the flow passages on the radially outer side of the flow passages, not shown, and the stator vanes 130 are arranged in plurality at intervals in the circumferential direction on the radially outer side of the blade rows of the guide vanes 120. A casing, not shown, is disposed radially outward of the stator blade 130.

The hollow arrows in fig. 12 indicate the direction of water flow when the turbine is operating, and the black arrows indicate the direction of water flow when the pump is operating. In the francis type turbine pump, when the turbine is operated, water from the casing flows along the stator blades 130 and the guide blades 120 and flows into the flow path as indicated by hollow arrows. The flow passage converts the energy of the water into a rotational force, thereby driving the generator motor via a main shaft, not shown. The water flowing out of the flow passage is guided to the tailrace through a draft tube not shown. On the other hand, during pump operation, as indicated by black arrows, the water flows in the opposite direction to that during turbine operation, and the water flowing in from the draft tube flows through the flow passage, along the guide vanes 120 and the stator vanes 130, and flows out from the casing to the upper tank.

The guide vanes 120 in such a francis type pump turbine are rotatable about the guide vane rotation axis, and the angle of the rotation is changed, whereby the flow path area of the flow path formed between the adjacent guide vanes 120 can be changed. Thus, the power generation output can be adjusted by changing the amount of water flowing into the flow channel.

However, fig. 13 shows a schematic perspective view of the guide vane 120, which views the guide vane 120 from above. As shown in fig. 13, in such a francis type pump turbine, the flow fs of water from the stator blade 130 becomes a two-dimensional shear flow having a velocity angle in the vertical direction, and flows toward the guide vane 120. Then, in such a flow, a low flow velocity region R is generated on the wall surface side of the shroud extremely close to the guide vane 120, particularly extremely close to the leading edge of the guide vane 120, and thereby the upper flow is involved in the lower slow flow, and a horseshoe vortex W may be generated. The generation of the horseshoe vortices W disturbs the flow of the water flowing into the guide vanes 120, and thus the loss of the flow on the guide vanes 120 may increase. Further, since water flows into the flow path in a turbulent flow, the loss of the flow in the flow path may increase.

Various techniques for reducing the loss due to the flow have been proposed. For example, the following techniques are known: a through hole is provided to penetrate the upper and lower end faces of the guide vane, and leakage flow between the guide vane and the fixed wall is suppressed by the through hole. Further, the following techniques are also known: a through hole is provided at the tip of the fixed blade, and the occurrence of separation around the fixed blade is suppressed by the through hole. Further, the following techniques are also known: by generating pulsation in the guide vane, the occurrence of separation in the periphery of the guide vane during partial load operation is suppressed.

Patent document 1: japanese laid-open patent publication No. H04-246279

patent document 2: japanese patent laid-open No. 2014-152708

Patent document 3: japanese patent laid-open publication No. 2005-207375

disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a hydraulic machine capable of suppressing generation of horseshoe vortices that may be generated around guide vanes and reducing loss of flow in the guide vanes and a flow passage.

A hydraulic machine according to an embodiment is a hydraulic machine in which a flow path is rotated by water flowing from a fixed blade to the flow path through a guide blade, and an upper cover is disposed above the fixed blade and the guide blade, and a lower cover is disposed below the fixed blade and the guide blade. The hydraulic machine further includes a suction mechanism capable of sucking water flowing between the stator vane and the guide vane in at least one of the upper cover side region and the lower cover side region.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to suppress the generation of horseshoe vortices that may be generated around the guide vanes and to reduce the loss of flow on the guide vanes and the flow passage.

Drawings

Fig. 1 is a meridional cross-sectional view of a francis-type pump water turbine according to a first embodiment.

Fig. 2 is a view of the fixed blades, guide blades, and under cover of the francis type pump turbine shown in fig. 1, as viewed along the rotational axis of the flow path.

Fig. 3 is a schematic perspective view of the fixed blade, the guide blade, and the under cover of the francis-type pump turbine shown in fig. 1, as viewed from above.

fig. 4 is a view of the stator blades, the guide blades, and the under cover of the francis type pump turbine according to the second embodiment, as viewed along the flow path rotation axis.

fig. 5 is a meridional cross-sectional view of a francis-type pump water turbine according to a third embodiment.

fig. 6 is a meridional cross-sectional view of a francis-type pump water turbine according to a fourth embodiment.

Fig. 7 is a meridional cross-sectional view of a francis-type pump water turbine according to the fifth embodiment.

fig. 8 is a meridional cross-sectional view of a francis-type pump water turbine according to a sixth embodiment.

Fig. 9(a) is a cross-sectional view of a guide vane of a francis type pump turbine according to the seventh embodiment, and (B) is a view of the guide vane shown in (a) and a stationary vane adjacent to the guide vane, as viewed along the rotational axis of the flow passage.

Fig. 10 is a cross-sectional view of a guide vane of a francis-type pump water turbine according to an eighth embodiment.

fig. 11(a) is a cross-sectional view of a guide vane of a francis type pump turbine according to a ninth embodiment, and (B) and (C) are views of the guide vane shown in (a) and a stationary vane adjacent to the guide vane, as viewed along a rotational axis of a flow path.

Fig. 12 is a plan view of a stationary blade row flow path formed by guide vanes and stationary blades of a general francis type water turbine.

fig. 13 is a schematic perspective view of a guide vane of the guide vane shown in fig. 12, as viewed from above.

Description of the symbols

1 … Francis type water turbine, 10 … casing, 12 … guide vane, 12A … inner diameter side wing surface, 12F … front end, 12R … rear end, 13 … fixed vane, 14 … flow channel, 16 … suction pipe, 16B … elbow part, 18U … upper cover, 18D … lower cover, 20 … flow channel side pressure chamber, 22 … guide vane main shaft, 30 … suction mechanism, 41 … groove, 42 … suction hole, 43 … pipe part, 421 … leading-in part, 421A … first leading-in part, 421B … second leading-in part, 421C … third leading-in part, 422 … confluence part, C1 … flow channel rotating shaft, L1 … guide vane rotating shaft

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(first embodiment)

Fig. 1 shows a francis type pump turbine 1 as an example of a hydraulic machine according to a first embodiment of the present invention. In the following description, the francis-type pump turbine 1 is simply referred to as a hydraulic turbine 1. The water turbine 1 includes a casing 10 into which water flows from an upper pool, not shown, through an iron pipe 11, a plurality of guide vanes 12, a plurality of stator vanes 13, and a flow passage 14.

In the hydraulic turbine 1, water from the casing 10 flows into the runner 14 through the stationary blade row flow path formed by the guide blades 12 and the stationary blades 13 during operation of the hydraulic turbine. Thereby, the flow path 14 rotates about the flow path rotation axis C1. In the following description, the term "axial" means a direction along the flow path rotation axis C1 or a direction along the flow path rotation axis C1. The term "circumferential" means a direction along the direction in which the flow path 14 rotates about the flow path rotation axis C1, and the term "radial" means a direction perpendicular to the flow path rotation axis C1.

The casing 10 is formed in a spiral shape, and when the turbine is operated, water flowing from the upper tank is supplied to the flow channel 14 through the stator blades 13 and the guide blades 12. The plurality of stator blades 13 are members for allowing water supplied from the casing 10 to flow into the guide blades 12, and are arranged at predetermined intervals in the circumferential direction on the inner side in the radial direction of the casing 10. The guide vanes 12 are members for allowing water flowing in from the fixed vanes 13 to flow into the flow passage 14, and are disposed at predetermined intervals in the circumferential direction on the inner side in the radial direction of the fixed vanes 13, and are disposed on the outer side in the radial direction of the flow passage 14.

The flow path 14 is configured to rotate about a flow path rotation axis C1 with respect to the housing 10, and the flow path rotation axis C1 is connected to a generator motor, not shown, via a main shaft 15 passing through the center thereof. The generator motor rotates through the flow path 14, thereby generating power. On the other hand, the pump operation is performed by rotating the flow path 14 by the generator motor. The draft pipe 16 discharges water flowing out of the flow channel 14 to a lower pool, not shown, during operation of the turbine, and allows water from the lower pool to flow toward the flow channel 14 through the draft pipe during operation of the pump.

Further, an upper shroud 18U is disposed above the fixed blades 13 and the guide blades 12, and a lower shroud 18D is disposed below the fixed blades 13 and the guide blades 12. The upper cover 18U covers the upper portions of the stator blades 13 and the guide blades 12, and also covers the upper portion (shroud) of the flow path 14. A flow passage back pressure chamber 19 is formed between the upper cover 18U and the flow passage 14. The lower shroud 18D covers the lower portions of the stator blades 13 and the guide blades 12, and covers the lower portion (band) of the flow path 14. A flow passage side pressure chamber 20 is formed between the lower cover 18D and the flow passage 14.

The guide vane 12 is coupled to a guide vane main shaft 22, and in the illustrated example, the guide vane main shaft 22 extends so as to penetrate the upper and lower shrouds 18U and 18D. The guide vanes 12 are rotatable about a guide vane rotation axis L1 extending on the central axis of the guide vane main shaft 22, and the angle of the rotation is changed, whereby the flow path area of the flow path formed between the adjacent guide vanes 12 can be changed. Thus, the power generation output can be adjusted by changing the amount of water flowing through the flow channel 14.

fig. 2 is a view of the stator blades 13, the guide blades 12, and the lower shroud 18D as viewed along the runner rotation axis C1 (axial direction), and shows the suction mechanism 30 provided in the hydraulic turbine 1 according to the present embodiment. As shown in fig. 2, a groove 41 is formed in the lower cover 18D, and a plurality of suction holes 42 are formed in the groove 41. The suction holes 42 are opened toward spaces between the guide vanes 12 and the stationary vanes 13, respectively. In the present embodiment, the grooves 41 and the suction hole 42 constitute the suction mechanism 30, and the suction mechanism 30 can suck water flowing through the region on the lower shroud 18D side between the fixed blades 13 and the guide blades 12 through the suction hole 42.

The angle of the guide vane 12 shown by a solid line in fig. 2 corresponds to the maximum efficiency point specified for the turbine. Specifically, the suction mechanism 30 can suck water flowing in a region on the lower shroud 18D side in a space between a circle Cg centered on a flow path rotation axis C1 passing through the leading edge e1 of each guide vane 12 at an angle corresponding to the highest efficiency point and a circle Cs centered on a flow path rotation axis C1 passing through a point closest to the guide vane 12 of each fixed vane 13. Here, the leading edge e1 of the guide vane 12 means a portion of the guide vane 12 where the end points on the fixed vane 13 side of the camber line are connected. The circle Cs may be referred to as a circle having the smallest radius that contacts the stator vane 13 around the flow path rotation axis C1.

More specifically, the groove 41 is formed on an arc centered on the flow passage rotation axis C1 passing between the stator vane 13 and the guide vane 12, particularly between the circle Cg and the circle Cs, when viewed in the axial direction. As shown in fig. 3, the groove 41 has a rectangular cross section in a direction intersecting the extending direction, and the suction hole 42 is open at the bottom surface of the groove 41 and extends linearly downward from the bottom surface of the groove 41. Accordingly, the groove 41 and the suction hole 42 are positioned between the circle Cg and the circle Cs in the downward direction when viewed in the axial direction, and water between the circle Cg and the circle Cs can be sucked through the suction hole 42. In the present embodiment, water taken in through the suction port 42 is sent to the outside of the hydraulic turbine 1 as an example.

To explain the arrangement of the slots 41 in more detail, the guide vanes 12' indicated by the two-dot chain lines in fig. 2 show a state in which the guide vanes 12 indicated by the solid lines are rotated to a mechanical limit opening degree (fully open state). A circle Cg1 in fig. 2 indicates a circle of maximum radius that is in contact with the guide vane 12' in a state of mechanical extreme opening about the flow path rotation axis C1. The groove 41 may be located between the circle Cg1 and the circle Cs if the mechanical limit opening is taken into consideration, and particularly in the illustrated example, the inner peripheral edge of the groove 41 substantially coincides with the arc of the circle Cg 1. When the groove 41 is located between the circle Cg1 and the circle Cs, the guide vane 12 does not cover the groove 41 due to the rotation thereof, and the groove 41 and the fixed vane 13 do not overlap each other in the axial direction. Accordingly, desired water can be sucked in a stable state by the suction mechanism 30 at all rotational positions of the guide vane 12, and the flow in the stationary vane 13 is not disturbed by the groove 41.

In fig. 2, a straight line a1 represents a straight line passing through the leading edge e1 of the guide vane 12 (12') and the flow path rotation axis C1 when the guide vane 12 is in the fully open state, and a straight line a2 represents a straight line passing through the leading edge e1 of the guide vane 12 and the flow path rotation axis C1 when the guide vane 12 is in the fully closed state. In the present embodiment, a plurality of, three as an example, suction holes 42 are provided in the groove 41 in a region between the straight line a1 and the straight line a 2. In addition, three suction holes 42 are also provided in the groove 41 in the region between the straight line a1 and the straight line a2 corresponding to the other guide vanes 12. However, the number and arrangement position of the suction holes 42 are not particularly limited. In the present embodiment, the groove 41 is circular, but instead, a plurality of arcuate grooves 41 may be formed in the circumferential direction. In this case, the grooves 41 are preferably formed so as to pass between the guide vanes 12 and the stator vanes 13 adjacent in the radial direction, respectively, and are preferably formed so that at least a part thereof is located in a region between the straight line a1 and the straight line a 2. The groove 41 may have a polygonal shape in a circumferential direction. Further, the groove 41 may be formed in a polygonal shape or a linear shape, and a plurality of grooves may be formed in the circumferential direction.

Next, the operation of the present embodiment will be described.

During the operation of the turbine, water introduced from the upper pool is introduced into the housing 10 through the iron pipe 11, and then, the water flows into the flow passage 14 from the housing 10 through the stator blades 13 and the guide blades 12. The flow path 14 is rotated by the pressure energy of the passing water, and drives a generator motor connected via a main shaft 15. Thereby, the generator motor generates electric power. Water flowing out of the flow channel 14 is discharged to the lower basin through the draft tube 16.

When water flows from the stator blades 13 to the guide blades 12, a low flow velocity region is generated on the lower shroud 18D side in the flow of water from the stator blades 13 to the guide blades 12. The low flow rate region means the following region: a region of slower flow is generated compared to the flow on the side of the middle position between the upper shroud 18U and the lower shroud 18D in the flow of water from the stator blades 13 to the guide blades 12. In the present embodiment, the water flowing through the low flow velocity region can be sucked through the suction hole 42 of the suction mechanism 30. By sucking water in this manner, the flow velocity of the water flowing from the stator vanes 13 to the guide vanes 12 can be made uniform, and horseshoe vortices that may be generated due to the generation of low flow velocity regions can be suppressed. This can suppress disturbance of the flow in the guide vane 12, and can suppress mixing of the horseshoe vortices on the outlet side of the guide vane 12 and the main flow (non-disturbed flow), thereby also suppressing disturbance of the flow in the flow passage 14.

Thus, according to the present embodiment, it is possible to suppress the generation of horseshoe vortices that may occur around the guide vanes 12, and to reduce the loss of flow in the guide vanes 12 and the flow passage 14. In the present embodiment, the groove 41 and the suction hole 42 are provided in the lower cover 18D, but the groove 41 and the suction hole 42 may be provided in both the lower cover 18D and the upper cover 18U, or the groove 41 and the suction hole 42 may be provided only in the upper cover 18U. When the groove 41 and the suction hole 42 are provided in the upper cover 18U, water in a low flow velocity region on the upper cover 18U side in the flow of water from the stator vanes 13 to the guide vanes 12 can be sucked.

In the present embodiment, the groove 41 is provided in the lower cover 18D, but the groove 41 may not be provided. However, in the case where the grooves 41 are provided as in the present embodiment, the suction holes 42 can suck water from a wide range through the grooves 41 as compared with the case where the grooves 41 are not provided, and therefore, water in a low flow velocity region can be efficiently sucked while the number of the suction holes 42 is suppressed.

(second embodiment)

Next, a second embodiment will be explained. Fig. 4 is a view of the stator blades, the guide blades, and the under cover of the francis type pump turbine according to the second embodiment, as viewed along the flow path rotation axis. The same components as those of the first embodiment are denoted by the same reference numerals in the present embodiment, and descriptions thereof are omitted.

In the present embodiment, the configuration of the groove 41 is different from that of the first embodiment. That is, as shown in fig. 4, the groove 41 in the present embodiment is formed on an arc centered on the guide vane rotation axis L1 passing between the adjacent guide vanes 12 and the fixed vane 13, for example, an arc constituting a part of a circle indicated by a broken line in fig. 4. The grooves 41 are provided for each combination of adjacent guide vanes 12 and stator vanes 13, and a plurality of suction holes 42 are provided in each groove 41. Here, in the present embodiment, at least a part of the groove 41 and the suction hole 42 is positioned between the circle Cg and the circle Cs. More specifically, in this example, a part of the groove 41 and the suction hole 42 is positioned between the circle Cg and the circle Cs, and the other part is positioned outside the region between the circle Cg and the circle Cs.

To describe the arrangement of the grooves 41 in the present embodiment in more detail, a circle Cg2 in fig. 4 indicates a circle having the largest radius among circles drawn by the guide vanes 12 (more specifically, the outer diameter side portions thereof) when the guide vanes 12 are driven (rotated) about the guide vane rotation axis L1. The circle Cg3 in fig. 4 represents the circle with the smallest radius among circles that are tangent to the stationary blades 13 with the guide blade rotation axis L1 as the center. Since the groove 41 in the present embodiment is located between the circles Cg2 and Cg3, in the illustrated example, the inner peripheral edge of the groove 41 substantially coincides with the arc of the circle Cg 2. When the groove 41 is located between the circle Cg2 and the circle Cg3, the guide vane 12 does not cover the groove 41 by its rotation, and the groove 41 and the fixed vane 13 do not overlap in the axial direction. Accordingly, desired water can be sucked in a stable state by the suction mechanism 30 at all rotational positions of the guide vane 12, and the flow in the stationary vane 13 is not disturbed by the groove 41.

With such an embodiment, it is possible to suppress the generation of horseshoe vortices that may be generated around the guide vanes 12, and to reduce the loss of flow in the guide vanes 12 and the flow passage 14. Therefore, in the present embodiment, since the suction holes 42 are provided in the grooves 41 close to the leading edge of the guide vane 12, the flow serving as the base of the horseshoe vortex which is particularly likely to be generated on the upstream side of the leading edge of the guide vane 12 can be effectively sucked. Therefore, the loss reduction effect can be improved.

(third embodiment)

Next, a third embodiment will be explained. Fig. 5 is a meridional cross-sectional view of a francis-type pump water turbine according to a third embodiment. In the present embodiment, the same components as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

In the first embodiment, the suction port 42 feeds the sucked water to the outside of the hydraulic turbine 1 as an example, but in the present embodiment, the water sucked into the suction port 42 is fed to the flow path side pressure chamber 20. Specifically, as shown in fig. 5, the suction mechanism 30 includes a pipe portion 43 that connects the suction port 42 to the flow path side pressure chamber 20. The configuration of the suction hole 42 is the same as that of the first embodiment.

With such an embodiment, it is possible to suppress the generation of horseshoe vortices that may be generated around the guide vanes 12, and to reduce the loss of flow in the guide vanes 12 and the flow passage 14. Therefore, in the present embodiment, the water sucked into the suction port 42 is sent to the flow path side pressure chamber 20 through the pipe portion 43. Accordingly, water can be easily sucked through the suction hole 42 by utilizing a differential pressure between the pressure in the flow passage side pressure chamber 20 and the pressure of the flow upstream of the guide vane 12. The pipe portion 43 in the present embodiment can also be applied to the second embodiment.

(fourth embodiment)

Next, a fourth embodiment will be explained. Fig. 6 is a meridional cross-sectional view of a francis-type pump water turbine according to a fourth embodiment. In the present embodiment, the same components as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, the water sucked into the suction hole 42 is sent to the space between the guide vane 12 and the flow channel 14. Specifically, as shown in fig. 6, the suction mechanism 30 includes a pipe portion 43, and the pipe portion 43 communicates the suction hole 42 and a space between the guide vane 12 and the flow passage 14. More specifically, the duct portion 43 communicates the suction hole 42 with a position on the downstream side of the guide vane pitch circle in the wing row of the guide vane 12. The configuration of the suction hole 42 is the same as that of the first embodiment.

With such an embodiment, it is possible to suppress the generation of horseshoe vortices that may be generated around the guide vanes 12, and to reduce the loss of flow in the guide vanes 12 and the flow passage 14. Therefore, in the present embodiment, the water sucked into the suction hole 42 is sent to the space between the guide vane 12 and the flow channel 14 through the pipe portion 43. This allows water sucked into the suction hole 42 to be utilized for rotation of the flow passage 14. The pipe portion 43 in the present embodiment can also be applied to the second embodiment.

(fifth embodiment)

Next, a fifth embodiment will be described. Fig. 7 is a meridional cross-sectional view of a francis-type pump water turbine according to the fifth embodiment. In the present embodiment, the same components as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, the water sucked into the suction hole 42 is sent to the inside of the elbow portion 16B of the draft tube 16. Specifically, as shown in fig. 7, the draft tube 16 includes: a draft section 16A extending downward from the lower cover 18D; a bent portion 16B bent and extending from the lower end of the draft portion 16A; and an enlarged pipe portion 16C extending laterally from the elbow portion 16B toward the lower tank side. On the other hand, the suction mechanism 30 has a pipe portion 43 that communicates the suction hole 42 with the inside of the elbow portion 16B. The configuration of the suction hole 42 is the same as that of the first embodiment.

with such an embodiment, it is possible to suppress the generation of horseshoe vortices that may be generated around the guide vanes 12, and to reduce the loss of flow in the guide vanes 12 and the flow passage 14. Therefore, in the present embodiment, the water sucked into the suction hole 42 is sent to the inside of the elbow portion 16B of the draft pipe 16 through the pipe portion 43. This can suppress the peeling flow that may occur inside the elbow portion 16B, and can effectively suppress the loss. The pipe portion 43 in the present embodiment can also be applied to the second embodiment.

(sixth embodiment)

Next, a sixth embodiment will be explained. Fig. 8 is a meridional cross-sectional view of a francis-type pump water turbine according to a sixth embodiment. In the present embodiment, the same components as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

The suction mechanism 30 in the present embodiment has a flow rate adjustment valve 44 for adjusting the amount of water sucked from the suction hole 42. Specifically, in the present embodiment, as shown in fig. 8, a flow rate adjustment valve 44 is provided in a pipe portion 43 similar to that of the fourth embodiment. The flow rate regulating valve 44 is configured to regulate the flow rate of water flowing through the pipe portion 43, thereby regulating the amount of water sucked into the suction hole 42.

according to such an embodiment, the amount of water sucked through the suction hole 42 can be adjusted according to the operating state between the fully open and fully closed states of the guide vane 12, and therefore, a situation in which water is excessively sucked can be avoided. The flow rate adjustment valve 44 as described above may be applied to the first to third and fifth embodiments.

(seventh embodiment)

Next, a seventh embodiment will be explained. Fig. 9 shows a cross-sectional view of a guide vane of a francis type water turbine pump according to the seventh embodiment, and (B) shows the guide vane shown in (a) and a stationary vane adjacent to the guide vane, as viewed along the rotational axis of the flow path. In the present embodiment, the same components as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

The present embodiment is different from the first to sixth embodiments in that the suction hole 42 of the suction mechanism 30 is provided in the guide vane 12. Specifically, in the present embodiment, as shown in fig. 9(a), the suction hole 42 provided in the guide vane 12 penetrates the inner diameter side surface 12A of the guide vane 12 from the tip 12F of the guide vane 12 on the fixed vane 13 side. More specifically, the suction hole 42 extends linearly from the front end 12F of the guide vane 12 toward the rear end 12R on the opposite side, i.e., the flow path 14 side, inside the guide vane 12, and then curves toward the inner diameter side airfoil surface 12A. The suction hole 42 is opened in a portion of the inner diameter-side airfoil surface 12A on the rear end portion 12R side of the guide vane 12.

In fig. 9(a), Y represents the chord length, the range represented by Yf represents the range from the leading edge of the guide vane 12 to the trailing edge to a distance of 0.15 × Y, and the range represented by Yr represents the range from the trailing edge of the guide vane 12 to the leading edge to a distance of 0.15 × Y. In the present embodiment, a portion located in the range denoted by Yf corresponds to the front end portion 12F, and a portion located in the range denoted by Yr corresponds to the rear end portion 12R. Further, the portion on the trailing end 12R side of the guide vane 12 on the inner diameter side airfoil surface 12A means a portion located closer to the trailing end 12R side than the midpoint of the chord length Y of the guide vane 12. In the illustrated example, the suction hole 42 opens to the inner diameter side airfoil surface 12A on the rear end portion 12R side of the guide vane 12.

On the other hand, in fig. 9(B), the angle of the guide vane 12 corresponds to the maximum efficiency point. In fig. 9B, the direction of the flow (strictly, the main flow) from the fixed vane 13 to the guide vane 12 is indicated by an arrow F, and an extension EL from the inner side of the guide vane 12 of the suction hole 42 to the fixed vane 13 side is shown. As indicated by the arrow F and the extension line EL, in the present embodiment, when the angle of the guide vane 12 is at an angle corresponding to the maximum efficiency point, the suction hole 42 opens in a direction parallel to the flow from the fixed vane 13 toward the guide vane 12. In the present embodiment, the suction holes 42 as described above are provided in the portions of the guide vanes 12 close to the upper shroud 18U and the lower shroud 18D, respectively, but the suction holes 42 may be provided only in one of the portions of the guide vanes 12 close to the upper shroud 18U and the lower shroud 18D.

In the present embodiment, water flowing from the stator blades 13 to the guide blades 12 and in a low flow velocity region that may be generated on the lower cover 18D side and the upper cover 18U side can be sucked through the suction hole 42 of the suction mechanism 30. By sucking water in this manner, the flow velocity of the water flowing from the fixed blades 13 to the guide blades 12 can be made uniform, and horseshoe vortices that may occur due to the occurrence of low flow velocity regions can be suppressed. This can suppress flow disturbance in the guide vane 12 and the flow passage 14. Thus, according to the present embodiment, it is possible to suppress the generation of horseshoe vortices that may be generated around the guide vane 12, and to reduce the loss of the flow in the guide vane 12 and the flow passage 14.

In the present embodiment, the water sucked in through the suction hole 42 is sent to the rear end portion 12R side of the guide vane 12 of the inner diameter-side airfoil surface 12A, and thereby the generation of separation vortex generated on the outlet side of the guide vane 12 can be suppressed. This makes it possible to further reduce the loss by rationalizing the flow flowing into the flow path 14.

(eighth embodiment)

Next, an eighth embodiment will be described. Fig. 10 is a cross-sectional view of a guide vane of a francis-type pump water turbine according to an eighth embodiment. In the present embodiment, the same components as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

The present embodiment is different from the seventh embodiment in the shape of the suction hole 42 of the suction mechanism 30. That is, as shown in fig. 10, the suction port 42 in the present embodiment includes: a plurality of, in the present embodiment, three introduction portions 421 that open in different directions from each other at the tip end portion 12F of the guide vane 12; and a merging portion 422 that merges the plurality of introduction portions 421 inside the guide vane 12 and opens to the inner diameter side surface 12A of the guide vane 12.

In the present embodiment, when the angle of the guide vane 12 is adjusted to a plurality of opening degrees that are intermediate opening degrees between the fully open and fully closed positions of the guide vane 12, any one of the plurality of introduction portions 421 is configured to open in a direction parallel to the flow from the fixed vane 13 toward the guide vane 12.

According to the present embodiment, when the angle of the guide vane 12 is adjusted to a plurality of opening degrees, which are intermediate opening degrees between the fully opened and fully closed positions of the guide vane 12, water in a low flow velocity region in the flow from the fixed vane 13 to the guide vane 12 can be efficiently sucked through any one of the plurality of introduction portions 421. This can effectively reduce the loss of the flow in the guide vane 12 and the flow passage 14 at a plurality of operating points.

(ninth embodiment)

Next, a ninth embodiment will be described. In fig. 11, (a) is a cross-sectional view of a guide vane of a francis type pump turbine according to the ninth embodiment, and (B) and (C) are views of the guide vane shown in (a) and its adjacent stator vane as viewed along the rotational axis of the flow channel. In the present embodiment, the same components as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

The present embodiment is different from the eighth embodiment in the shape of the suction hole 42 of the suction mechanism 30. Specifically, the suction hole 42 includes a first introduction portion 421A, a second introduction portion 421B, and a third introduction portion 421C as the introduction portion 421. When the angle of the guide vane 12 is at an angle corresponding to the maximum efficiency point, the first introduction portion 421A opens in a direction parallel to the flow from the fixed vane 13 toward the guide vane 12. As shown in fig. 11(B), when the angle of the guide vane 12 is at the fully open angle, the second introduction portion 421B opens in a direction parallel to the flow F from the fixed vane 13 toward the guide vane 12. As shown in fig. 11(C), when the angle of the guide vane 12 is at the fully closed angle, the third introduction portion 421C opens in a direction parallel to the flow F from the fixed vane 13 toward the guide vane 12.

According to the present embodiment as described above, in the case where the angle of the guide vane 12 is adjusted to a plurality of opening degrees, which are intermediate opening degrees between the fully open and fully closed positions of the guide vane 12, as in the eighth embodiment, water in a low flow velocity region in the flow from the fixed vane 13 to the guide vane 12 can be efficiently sucked through any one of the plurality of introduction portions 421A, 421B, and 421C. This can effectively reduce the loss of the flow in the guide vane 12 and the flow passage 14 at a plurality of operating points.

While several embodiments of the present invention have been described above, the above embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and variations thereof are included in the scope and gist of the invention, and are included in the invention described in the scope of the claims and the equivalent scope thereof.

For example, although the pipe portion 43 extends from the lower cover 18D in the third to sixth embodiments, such a pipe portion 43 may be connected to the suction hole 42 provided in the upper cover 18U.

Claims (7)

1. A hydraulic machine in which a flow path is rotated by water flowing from a fixed blade to the flow path through a guide blade,

An upper cover is disposed above the fixed blades and the guide blades, and a lower cover is disposed below the fixed blades and the guide blades,

The hydraulic machine includes a suction mechanism capable of sucking water flowing in at least one of the upper shroud side region and the lower shroud side region between the stator vane and the guide vane,

The suction mechanism has a suction hole formed in at least one of the upper cover and the lower cover and opened to a space between the guide vane and the stationary vane,

The suction mechanism can suck water through the suction hole.

2. The hydraulic machine of claim 1,

The suction mechanism has a groove formed on at least one of the upper cover and the lower cover,

The groove is formed to pass between the stator blade and the guide blade, and the suction hole is provided in the groove.

3. The hydraulic machine of claim 2,

The groove is formed on an arc passing through between the stator blade and the guide blade and centering on a rotation axis of the flow path.

4. The hydraulic machine of claim 2,

The guide vane can rotate around the guide vane rotating shaft,

The groove is formed on an arc passing through between the stationary blade and the guide blade and having the guide blade rotation axis as a center.

5. The hydraulic machine of claim 1,

The suction mechanism has a suction hole penetrating from the end of the guide vane on the fixed vane side to the inner diameter side surface of the guide vane,

The suction hole is opened at an end portion of the guide vane on the inner diameter side blade surface on the flow passage side.

6. The hydraulic machine of claim 5,

The suction hole has: a plurality of introduction portions that open in different directions at the end portions of the guide vane on the stationary blade side; and a merging section that merges the plurality of introduction sections into the guide vane and opens at an inner diameter side surface of the guide vane.

7. The hydraulic machine of claim 6,

The plurality of introduction portions include: a first introduction portion that opens in a direction parallel to a flow from the fixed blade toward the guide blade when an angle of the guide blade is an angle corresponding to a maximum efficiency point; a second introduction portion that opens in a direction parallel to a flow from the fixed vane toward the guide vane when the angle of the guide vane is at a fully open angle; and a third introduction portion that opens in a direction parallel to a flow from the fixed blade toward the guide blade when the angle of the guide blade is at the fully closed angle.