JP2016205226A - Runner and hydraulic machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a runner capable of reducing hydraulic loss by suppressing flow deviation that may be generated when the flow velocity of water near the negative pressure surface of a runner blade is faster than the flow velocity of water near the pressure surface of the runner blade.SOLUTION: A runner 4 according to this embodiment includes a crown 8, a band 9, and a plurality of runner blades 10 provided between the crown 8 and the band 9. In a part or the whole of a region on the side of a negative pressure surface 10n of the runner blade 10 in a water flowing surface 90 of the band 9, provided is a recess part 90A adjacent to the part or whole thereof in a circumferential direction and recessed to an anti-flow passage side with respect to a root portion 91 of the water flowing surface 90 of the band 9 on a pressure surface 10p of the runner blade 10.SELECTED DRAWING: Figure 2

Description

  Embodiments described herein relate generally to a runner and a hydraulic machine.

  FIG. 6 shows a meridional section of a typical Francis type turbine. In the Francis type turbine as shown in FIG. 6, during the power generation operation, water flows from the casing 1 through the stay vane 2 and the guide vane 3 into the runner 4. The runner 4 is rotationally driven by the water flow from the guide vane 3, and the generator 7 is driven via the main shaft 6. On the other hand, the water that has driven the runner 4 flows out to the water discharge channel through the suction pipe 5. Further, during the power generation operation, the amount of power generation can be changed by adjusting the amount of water flowing into the runner 4 by changing the opening of the guide vane 3. The runner 4 includes a crown 8 and a band 9 having a symmetrical shape with the rotation center C1 of the main shaft 6 as a central axis, and a runner blade 10. A plurality of runner blades 10 are provided between the crown 8 and the band 9 at intervals in the circumferential direction.

  Such hydraulic machines are required to have high performance from the viewpoint of effective use of renewable energy. For this reason, optimization of the flow path shape is being promoted by various methods.

  In the Francis type turbine as shown in FIG. 6, in particular, the runner 4 of the flow path constituent parts is the part where the flow velocity becomes the highest, and the rotational flow at the inlet is made almost non-circular at the outlet to generate rotational energy. It is an important member. In such a runner 4, most of the flow path loss occurs. Therefore, improving the performance of the runner 4 is an important research subject.

  In FIG. 6, a line L1 indicated by a broken line indicates an ideal streamline. When water flows along the streamline L1, an ideal operation is performed. However, during actual operation, as indicated by the arrow X, a secondary flow (uneven flow) occurs, and water often flows away from the streamline L1. Such suppression of the secondary flow is effective in improving the performance of the runner 4 in the Francis turbine.

  In FIG. 6, two lines L1 are shown. These two lines L1 divide the flow path from the crown 8 to the band 9 in the meridional flow path shown in FIG. It is also a virtual dividing line that is divided into three equal parts in the example. FIG. 7 is a view showing a part of a cross section in which a flow path cross section along one of the virtual dividing lines L1 is continuous over the entire circumference. FIG. 8 shows an inter-blade flow path diagram of the runner 4 in which a part of a cross section in which the flow path cross section along the line L2 indicated by a two-dot chain line in FIG. Yes.

  7 and 8, a region near the pressure surface 10 p of the runner blade 10 is denoted by reference numeral 11, and a region near the negative pressure surface 10 n of the runner blade 10 is denoted by reference numeral 12. As indicated by arrows Y and Z in FIG. 7, in the Francis turbine, the water flow rate in the region 12 near the negative pressure surface 10n tends to be faster than the water flow rate in the region 11 near the pressure surface 10p. . It is also effective in improving the performance of the runner 4 in the Francis type turbine to suppress such flow unevenness.

  In the field of such Francis type turbines, various techniques for improving the performance of the runner have been proposed in the past by optimizing the blade shape, adding additional auxiliary blades, and improving the blade arrangement position.

Japanese Patent No. 40944495 Japanese Patent No. 3524955 Japanese Patent No. 3782753

  However, the performance of a conventional Francis turbine runner composed of an axisymmetric crown and band and runner blades is approaching the limit performance at present. For this reason, there has been a problem that further improvement in performance cannot be easily achieved.

  The present invention has been made in order to solve the above-described problems, and the flow of water that can be generated by increasing the flow velocity of water near the negative pressure surface of the runner blade is higher than the flow velocity of water near the pressure surface of the runner blade. It aims at providing the runner and hydraulic machine which can reduce a hydraulic loss by suppressing bias.

  The runner according to the embodiment includes a crown, a band, and a plurality of runner blades provided between the crown and the band. A part or all of the area on the suction surface side of the runner blade on the surface of the flow of the band is adjacent to the pressure surface of the runner blade on the surface of the band that is adjacent to the part or the whole in the circumferential direction. A recessed portion is provided that is recessed on the side opposite to the flow path from the portion.

  A runner according to another embodiment includes a crown, a band, and a plurality of runner blades provided between the crown and the band. A part or all of the region on the pressure surface side of the runner blade on the water surface of the band is adjacent to the part or all of the region on the pressure surface side of the runner blade in the circumferential direction. A convex portion that protrudes further toward the flow path than the portion is provided.

  A runner according to still another embodiment includes a crown, a band, and a plurality of runner blades provided between the crown and the band. A part or all of the region on the suction surface side of the runner blade on the flow surface of the crown is adjacent to the pressure surface of the runner blade on the flow surface of the crown. A recessed portion is provided that is recessed on the side opposite to the flow path from the portion.

A runner according to still another embodiment includes a crown, a band, and a plurality of runner blades provided between the crown and the band. A part or all of the region on the pressure surface side of the runner blade on the flow surface of the crown is adjacent to the pressure surface side of the runner blade on the flow surface of the crown. A convex portion that protrudes further toward the flow path than the portion is provided.
The hydraulic machine according to the embodiment includes any one of the runners described above.

  According to the present invention, hydraulic loss is reduced by suppressing the flow bias that can be caused by the increased flow rate of water near the negative pressure surface of the runner blades compared to the flow rate of water near the pressure surface of the runner blades. it can.

It is meridional surface sectional drawing of the Francis type water turbine concerning a 1st embodiment. (A) is an enlarged view of the main part of FIG. 1, (B) is a planar development of a part of a cross-section in which the cross-section of the flow path along the line II-II in (A) is continued all around. FIG. (A) is a meridional cross-sectional view of the Francis type turbine according to the second embodiment, and (B) is a cross-section in which the cross-section of the flow path along the line III-III in (A) is continuous over the entire circumference. FIG. 2 is a flow diagram between blades in which a part of the blade is developed in a plane. (A) is a meridional cross-sectional view of the Francis type turbine according to the third embodiment, and (B) is a cross section in which the cross-section of the flow path along the line IV-IV in (A) is continuous over the entire circumference. FIG. 2 is a flow diagram between blades in which a part of the blade is developed in a plane. (A) is a meridional section view of the Francis type turbine according to the fourth embodiment, and (B) is a section in which the section of the flow path along the line V-V in (A) is continuous over the entire circumference. FIG. 2 is a flow diagram between blades in which a part of the blade is developed in a plane. It is a meridional section view of a general Francis type turbine. It is the figure which showed a part of cross section which made the flow-path cross section along the virtual dividing line which divides | segments the flow path from the crown to a band in the meridional flow path shown in FIG. . FIG. 7 is an inter-blade channel diagram in which a part of a cross section in which a channel cross section along a line L2 indicated by a two-dot chain line in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings to be described below, the same reference numerals are given to the same components as those of the general Francis type turbine described in FIG.

(First embodiment)
FIG. 1 shows a Francis turbine 100 as a hydraulic machine according to the first embodiment. The Francis type turbine 100 includes a casing 1 into which water flows from an upper pond (not shown) through an iron pipe, a plurality of stay vanes 2, a plurality of guide vanes 3, and a runner 4. The casing 1 supplies the water flowing in from the upper pond to the stay vane 2 at a uniform flow velocity. The plurality of stay vanes 2 are for guiding water flowing out from the casing 1 to the guide vanes 3, and are arranged at predetermined intervals in the circumferential direction on the inner peripheral side of the casing 1.

  The plurality of guide vanes 3 are for guiding the inflowing water to the runner 4, and are arranged at a predetermined interval in the circumferential direction on the inner peripheral side of the stay vane 2. Each of the guide vanes 3 can adjust the opening degree by rotating. Thereby, the power generation amount can be changed by adjusting the amount of water flowing into the runner 4.

  The runner 4 is configured to be rotatable about the rotation center C <b> 1 with respect to the casing 1, and is rotated by water flowing out from the guide vane 3. The runner 4 includes a crown 8, a band 9, and a plurality of runner blades 10 provided between the crown 8 and the band 9. The plurality of runner blades 10 are arranged at predetermined intervals in the circumferential direction.

  A generator 7 is connected to the runner 4 via a main shaft 6, and the generator 7 generates power by being rotated by the runner 4. A suction pipe 5 is provided on the downstream side of the runner 4. The water that has flowed out of the runner 4 is discharged to the water discharge channel through the suction pipe 5.

  2A is an enlarged view of the main part of FIG. 1, and FIG. 2B is a cross-sectional view in which the cross-section of the flow path along the line II-II in FIG. FIG. 3 is a flow diagram between blades in which a part is developed in a plane. In FIG. 2 (B), the pressure surface 10p and the negative pressure surface 10n of the runner blade 10 are shown. Further, the symbol F in the figure indicates a flow path formed between the crown 8 and the band 9.

  In the inter-blade channel diagram of FIG. 2 (B), the portion on the negative pressure surface 10n side of the runner blade 10 on the flowing water surface 90 of the band 9 is adjacent to this portion in the circumferential direction, and another runner blade on the flowing water surface 90. A recessed portion 90 </ b> A is provided that is recessed on the side opposite to the flow path from the base portion 91 (hereinafter, referred to as the pressure surface side base portion 91) with the ten pressure surfaces 10 p. A broken line in FIG. 2B indicates the surface position of the pressure surface side root portion 91.

  In the present embodiment, such a recess 90 </ b> A is provided along the streamline direction in the entire region on the negative pressure surface 10 n side of the runner blade 10 in the water flow surface 90 of the band 9. Note that the concave portion 90A may be provided in a part of the region on the negative pressure surface 10n side in the flowing water surface 90. In this case, it is preferable that the concave portion 90 </ b> A is partially provided on the downstream side of the flowing water surface 90.

  The operation of the present embodiment will be described. In the runner 4, the distance between the crown 8 near the suction surface 10n of the runner blade 10 and the band 9 is relatively longer than that near the pressure surface 10p. As a result, the cross-sectional area in the vicinity of the negative pressure surface 10n in the flow path F is larger than the cross-sectional area in the vicinity of the pressure surface 10p, whereby the flow velocity of water in the vicinity of the negative pressure surface 10n can be reduced. Thereby, the flow rate difference of water between the negative pressure surface 10n vicinity and the pressure surface 10p vicinity can be reduced.

  Therefore, according to the present embodiment, it is possible to suppress a flow deviation that may be caused by an increase in the flow velocity of water near the negative pressure surface of the runner blade 10 compared to the flow velocity of water near the pressure surface of the runner blade 10. Thus, hydraulic loss can be reduced.

(Second Embodiment)
Hereinafter, a second embodiment will be described. FIG. 3A is a meridional cross-sectional view of the Francis turbine according to the second embodiment, and FIG. 3B is a cross-sectional view taken along the line III-III in FIG. It is the inter-blade channel | path figure which expand | deployed planarly a part of the cross section continued to the periphery. In addition, about the component similar to 1st Embodiment in this Embodiment, the same code | symbol is shown and description is abbreviate | omitted.

  In the inter-blade channel diagram of FIG. 3B, the portion of the runner blade 10 on the pressure surface 10p side of the flow surface 90 of the band 9 is adjacent to this portion in the circumferential direction, and another runner blade on the flow surface 90. A convex portion 90 </ b> B is provided that protrudes more toward the flow path than a base portion 92 (hereinafter referred to as a negative pressure surface side root portion 92) with the 10 suction surfaces 10 n. A broken line in FIG. 3B indicates the surface position of the suction surface side root portion 92.

  In the present embodiment, such a convex portion 90 </ b> B is provided along the streamline direction in the entire region on the pressure surface 10 p side of the runner blade 10 on the water flow surface 90 of the band 9. In addition, the convex part 90B may be provided in a part of the region on the pressure surface 10p side in the flowing water surface 90. In this case, it is preferable that the convex portion 90 </ b> B is partially provided on the downstream side of the flowing water surface 90.

  The operation of the present embodiment will be described. In the runner 4, the distance between the crown 8 near the pressure surface 10 p of the runner blade 10 and the band 9 is relatively shorter than that near the negative pressure surface 10 n. As a result, the cross-sectional area near the pressure surface 10p in the flow path F is reduced more than the cross-sectional area near the negative pressure surface 10n, whereby the flow velocity of water near the pressure surface 10p can be increased. Thereby, the flow rate difference of water between the negative pressure surface 10n vicinity and the pressure surface 10p vicinity can be reduced.

  Therefore, also by this embodiment, by suppressing the flow deviation that may be caused by the increase in the flow velocity of water near the negative pressure surface of the runner blade 10 compared to the flow velocity of water near the pressure surface of the runner blade 10. , Hydraulic loss can be reduced.

(Third embodiment)
The third embodiment will be described below. FIG. 4A is a meridional cross-sectional view of the Francis turbine according to the third embodiment, and FIG. 4B is a cross-sectional view taken along the line IV-IV in FIG. It is the inter-blade channel | path figure which expand | deployed planarly a part of the cross section continued to the periphery. In addition, about the component similar to the 1st and 2nd embodiment in this Embodiment, the same code | symbol is shown and description is abbreviate | omitted.

  In the inter-blade channel diagram of FIG. 4 (B), the portion on the negative pressure surface 10 n side of the runner blade 10 on the flow surface 80 of the crown 8 is adjacent to this portion in the circumferential direction, and another runner blade on the flow surface 80. A concave portion 80 </ b> A is provided which is recessed on the side opposite to the flow path from the base portion 81 (hereinafter referred to as the pressure surface side base portion 81) with the ten pressure surfaces 10 p. The broken line in FIG. 4B indicates the surface position of the pressure surface side root portion 81.

  In the present embodiment, such a recess 80 </ b> A is provided along the streamline direction in the entire region of the flow surface 80 of the crown 8 on the negative pressure surface 10 n side of the runner blade 10. Note that the recess 80 </ b> A may be provided in a part of the area on the negative pressure surface 10 n side in the flowing water surface 80. In this case, the recess 80 </ b> A is preferably provided partially on the downstream side of the flowing water surface 80.

  In the present embodiment, as in the first embodiment, in the runner 4, the distance between the crown 8 near the suction surface 10n of the runner blade 10 and the band 9 is smaller than that near the pressure surface 10p. , Become relatively long. As a result, the cross-sectional area in the vicinity of the negative pressure surface 10n in the flow path F is larger than the cross-sectional area in the vicinity of the pressure surface 10p, whereby the flow velocity of water in the vicinity of the negative pressure surface 10n can be reduced. Thereby, the flow rate difference of water between the negative pressure surface 10n vicinity and the pressure surface 10p vicinity can be reduced.

  Therefore, also by this embodiment, by suppressing the flow deviation that may be caused by the increase in the flow velocity of water near the negative pressure surface of the runner blade 10 compared to the flow velocity of water near the pressure surface of the runner blade 10. , Hydraulic loss can be reduced.

(Fourth embodiment)
Hereinafter, a fourth embodiment will be described. FIG. 5A is a meridional cross-sectional view of the Francis turbine according to the fourth embodiment, and FIG. 5B is a cross-sectional view taken along the line V-V in FIG. It is the inter-blade channel | path figure which expand | deployed planarly a part of the cross section continued to the periphery. In addition, about the same component as the 1st thru | or 3rd Embodiment in this Embodiment, the same code | symbol is shown and description is abbreviate | omitted.

  In the inter-blade channel diagram of FIG. 5B, the portion on the pressure surface 10 p side of the runner blade 10 on the flow surface 80 of the crown 8 is adjacent to the other runner blade on the flow surface 80 adjacent to the portion in the circumferential direction. A convex portion 80 </ b> B that protrudes further to the flow path side than the root portion 82 (hereinafter referred to as the suction surface side root portion 82) with the 10 suction surfaces 10 n is provided. A broken line in FIG. 5B indicates the surface position of the suction surface side root portion 82.

  In the present embodiment, such convex portions 80 </ b> B are provided along the streamline direction in the entire region on the pressure surface 10 p side of the runner blade 10 on the flow surface 80 of the crown 8. In addition, the convex part 80B may be provided in a part of the region on the pressure surface 10p side in the flowing water surface 80. In this case, it is preferable that the convex portion 80 </ b> B is partially provided on the downstream side of the flowing water surface 80.

  In the present embodiment, as in the second embodiment, in the runner 4, the distance between the crown 8 near the pressure surface 10p of the runner blade 10 and the band 9 is smaller than that near the negative pressure surface 10n. , Relatively short. As a result, the cross-sectional area near the pressure surface 10p in the flow path F is reduced more than the cross-sectional area near the negative pressure surface 10n, whereby the flow velocity of water near the pressure surface 10p can be increased. Thereby, the flow rate difference of water between the negative pressure surface 10n vicinity and the pressure surface 10p vicinity can be reduced.

  Therefore, also by this embodiment, by suppressing the flow bias that can be caused by the increase in the flow velocity of water near the negative pressure surface of the runner blade compared to the flow velocity of water near the pressure surface of the runner blade 10, Hydraulic loss can be reduced.

  Although the embodiment of the present invention has been described above, the above embodiment is presented as an example, and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, as a modification of the first embodiment, a band adjacent to a part or all of the region on the pressure surface 10p side of the runner blade 10 on the flowing water surface 90 of the band 9 in the circumferential direction. The convex part 90B which protrudes in the flow path side rather than the negative pressure surface side root part 92 in the 9 flowing water surface 90 may be provided.

  Further, in the above modification, the flow surface 80 of the crown 8 that is adjacent to a part or all of the region on the suction surface 10n side of the runner blade 10 on the flow surface 80 of the crown 8 in the circumferential direction. A recess 80 </ b> A may be provided which is recessed toward the flow channel side from the pressure surface side root portion 81. Furthermore, in this modification, in addition to the above-described concave portion 80A, the convex portion 80B described in the fourth embodiment may be provided.

  Further, as a modification of the third embodiment, a crown that is adjacent to a part or all of the region on the pressure surface 10p side of the runner blade 10 on the flowing water surface 80 of the crown 8 in the circumferential direction. The convex part 80B which protrudes in the flow path side rather than the negative pressure surface side root part 82 in the 8 flowing water surface 80 may be provided.

4 runners, 8 crowns, 80 flowing water surfaces, 80A concave portions, 80B convex portions, 81, 82 root portions, 9 bands, 90 flowing water surfaces, 90A concave portions, 90B convex portions, 91, 92 root portions, 10 runner blades, 10p pressure surfaces 10n suction surface, 100 Francis type water wheel, F channel.

Claims (6)

With the crown,
With the band,
A plurality of runner blades provided between the crown and the band;
With
A part or all of the area on the suction surface side of the runner blade on the surface of the flow of the band is adjacent to the pressure surface of the runner blade on the surface of the band that is adjacent to the part or the whole in the circumferential direction. A runner characterized in that a recess is provided on the side opposite to the flow path from the portion. With the crown,
With the band,
A plurality of runner blades provided between the crown and the band;
With
A part or all of the region on the pressure surface side of the runner blade on the water surface of the band is adjacent to the part or all of the region on the pressure surface side of the runner blade in the circumferential direction. A runner characterized in that a protrusion is provided that protrudes further toward the flow path than the portion. With the crown,
With the band,
A plurality of runner blades provided between the crown and the band;
With
A part or all of the region on the suction surface side of the runner blade on the flow surface of the crown is adjacent to the pressure surface of the runner blade on the flow surface of the crown. A runner characterized in that a recess is provided on the side opposite to the flow path from the portion. With the crown,
With the band,
A plurality of runner blades provided between the crown and the band;
With
A part or all of the region on the pressure surface side of the runner blade on the flow surface of the crown is adjacent to the pressure surface side of the runner blade on the flow surface of the crown. A runner characterized in that a protrusion is provided that protrudes further toward the flow path than the portion.   A part or all of the region on the pressure surface side of the runner blade on the water surface of the band is adjacent to the part or all of the region on the pressure surface side of the runner blade in the circumferential direction. The runner according to claim 1, wherein a convex portion that protrudes further toward the flow path than the portion is provided.   A hydraulic machine comprising the runner according to any one of claims 1 to 5.

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