JP2010112336A - Francis hydraulic machine, and runner for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems wherein, it is anticipated that in a runner with both a straightening blade and an intermediate blade short in blade length added to a normal runner, improved efficiency in an undesigned point is achieved in comparison with the other existing runner, however, it is still insufficient for reducing a hydraulic loss. <P>SOLUTION: The runner for a Francis hydraulic machine includes: a runner crown 2; a runner band 3; runner blades 4; the straightening blades 6 arranged along a flow passage between the runner crown 2 and the runner band 3 and intersecting with each runner blade 4; and short runner blades 5a, 5b shorter in blade length than the runner blades 4 and arranged in a flow passage formed by the runner crown, the straightening blades 6, and the adjacent blades 4. B1 represents a distance between the runner crown on the peripheral side of the runner and the straightening blade, L1 represents a distance between the runner blades in a runner blade inlet on a side formed by the runner crown and the straightening blade, and L11 represents a distance from the pressure surface of the runner blade to the vacuum surface of the short runner blade. In this case, the distance B1 between the runner crown 2 and the straightening blade 6 is set to satisfy formula (1): 0.8×L11≤B1≤1.2×L11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a Francis-type hydraulic machine, and more particularly to a Francis-type hydraulic machine in which a rectifying plate is provided between a runner crown and a runner band and the runner thereof.

  Francis type hydraulic machines include Francis type turbines, Francis type pumps, Francis type pump turbines, and the like.

Hereinafter, a Francis turbine will be described as a typical example of a Francis hydraulic machine with reference to FIG.
FIG. 8 is a longitudinal sectional view drawn by paying attention to a runner portion of a general Francis type turbine.
The runner 1 of the Francis-type water turbine is attached to the lower end portion of the main shaft 11, and a runner crown 2 that is formed in a substantially conical shape, and an annular shape that is disposed on the extension line of the center line of the main shaft 11 and spaced from the runner crown 2. , And a plurality of wing-like runner blades 4 arranged at a substantially equal pitch in the circumferential direction with respect to the flow path formed between the runner crown 2 and the runner band 3. Reference numeral 2C denotes a runner cone provided at the center (exit side) of the runner crown 2.

  Reference numeral 7 denotes a spiral casing formed so as to surround the outer peripheral portion which becomes the running water inlet portion of the runner 1 configured as described above, and the pitch is substantially equal over the entire circumference of the inner peripheral portion outlet of the casing 7. Then, the stay vanes 8 are arranged radially, and a guide vane 9 whose opening degree can be adjusted is provided further on the inner peripheral side of the stay vane 8, that is, between the stay vane 8 and the runner 1 inlet.

  During the power generation operation of the Francis turbine, water that flows out from the casing 7 through the stay vanes 8 and the guide vanes 9 flows from the flowing water inlet of the outer periphery of the runner 1 toward the runner cone 2C in the center, and flows downstream in the axial direction. To do. At this time, since the flowing water acts on the runner blades 4, the runner 1 is rotationally driven by reaction force. The running water that has driven the runner 1 flows out to a water discharge channel (not shown) through a suction pipe 10 connected to the runner outlet. The runner 1 drives the generator 12 by the main shaft 11.

  The guide vane 9 adjusts the amount of water flowing into the runner 1 by changing the opening during operation, thereby changing the power generation amount. By the way, when the opening degree of the guide vane 9 is adjusted and the amount of water is changed, the distribution of the flowing water flowing in the runner 1 greatly changes depending on the operation state as shown in FIG.

  FIG. 9 shows a schematic diagram of the meridional surface flow in the runner 1 depending on the amount of water. In FIG. 9, (a) is a schematic diagram of the meridional surface flow at the design point, and (b) is a diagram at the time of small flow operation. A schematic diagram of the meridional flow, (c) is a schematic diagram of the meridional flow during a large flow rate operation.

  9 (a) to 9 (c), the meridional flow of the runner 1 is a dynamic pressure 14 of the water flow (an arrow pointing in the direction flowing into the runner 1 from the guide vane 9) to push the flow toward the inner peripheral side. , Determined by the balance of the centrifugal force 15 (arrow opposite to the arrow 14) due to the rotation of the runner 1 trying to push the flow to the outer peripheral side.

  For this reason, when operating at the design point of FIG. 9A, that is, at a point where the power generation efficiency is desired to be maximized, although a slight dead water region 16 is formed immediately below the runner cone 2C at the tip of the runner crown 2, a stable flow is achieved. Maintained. On the other hand, at the operating point where the amount of water is smaller than the design point, the centrifugal force 15 is relatively large and the flow of water is biased toward the outer peripheral side. Therefore, as shown in FIG. A large dead water region 16 is formed immediately below. On the contrary, in FIG. 9 (c), where the amount of water is larger than the design point, the centrifugal force 15 becomes relatively small and the flow of water is biased toward the inner peripheral side, and a dead water region 16 is formed along the suction pipe 10 side.

  The deviation of the water flow described above is referred to as a secondary flow and is a main cause of hydraulic loss occurring in the runner 1 at a non-design point. As a method of reducing the secondary flow at such a non-design point, conventionally, as shown in FIG. 10, the chord length of the runner blade 4 is provided in the inlet-side flow path between the runner crown 2 and the runner band 3. A method of providing a shorter rectifying blade 6 has been proposed (see, for example, Patent Documents 1 and 2).

  In addition, as shown in FIG. 11, a method has also been proposed in which runner blades 5 having a blade length shorter than the normal runner blades 4 are provided between adjacent normal runner blades 4 in the circumferential direction (for example, Patent Document 3). 4).

Furthermore, although not shown, a flow straightening plate (rectifying blade) shorter than the chord length of the runner blade is provided in the inlet-side flow path between the runner crown and the runner band, and the blade length is short between adjacent runner blades. A method of providing intermediate blades in the circumferential direction has also been proposed (see, for example, Patent Document 5).
JP-A-8-296544, JP 2005-133698 A, Japanese Patent No. 3782752 JP 2003-65198 A JP-A-57-126666,

  However, as in Patent Documents 1 and 2, a runner in which a rectifying blade is provided between the runner crown and the runner band, or a runner in which runner blades and short blade runner blades are alternately provided as in Patent Documents 3 and 4. However, there is a limit to reducing the secondary flow loss at the non-design point.

  Furthermore, as in Patent Document 5, a runner in which both a current plate and an intermediate blade with a short blade length are added to a normal runner is expected to improve efficiency at a non-design point compared to other conventional runners. It is still not enough to reduce hydraulic loss. For example, specify the optimal range of the position of the intermediate blades and rectifying plates, or optimize the number of runner blades and short blade runner blades depending on whether overload is important during turbine operation or partial load is important Therefore, there is room for further efficiency improvement.

  Accordingly, the present invention provides runner blades at a predetermined pitch in the circumferential direction in the flow path between the runner crown and the runner band, and provides straightening blades substantially parallel to the runner crown and the runner band. In a Francis-type hydraulic machine runner equipped with short blade runner blades with short blade lengths, hydraulic loss is further reduced by optimizing the position of the rectifying blades and optimizing the number of runner blades and short blade runner blades. An object of the present invention is to provide a Francis-type hydraulic machine that can be reduced and a runner thereof.

  In order to achieve the above object, the invention according to claim 1 includes a runner crown attached to a main shaft, and an annular runner band disposed at a position spaced from the runner crown on an extension line of the main shaft center line. A plurality of runner blades arranged at a substantially predetermined pitch in the circumferential direction with respect to the flow path formed between the runner crown and the runner band, and provided along the flow path between the runner crown and the runner band, And a rectifying blade intersecting each runner blade, and a short blade runner blade provided in a flow path formed by the runner crown, the rectifying blade and the adjacent runner blade, and having a blade length shorter than the runner blade. The distance between the runner crown on the outer peripheral side of the runner and the rectifying blade is B1, and the distance between the runner blades at the runner blade inlet portion on the side formed by the runner crown and the rectifying blade is When the separation is L1, and the distance from the pressure surface of the runner blade to the suction surface of the short blade runner blade is L11, 0.8 × L11 ≦ B1 ≦ 1.2 × L11 (1) is satisfied. The distance B1 between the runner crown and the rectifying blade is set.

  According to a second aspect of the present invention, there is provided a runner crown attached to the main shaft, an annular runner band disposed at a position spaced from the runner crown on an extension of the main shaft center line, and the runner crown and runner band. A plurality of runner blades arranged at a predetermined pitch in the circumferential direction with respect to the flow path formed therebetween, and provided along the flow path between the runner crown and the runner band, and intersects each runner blade. And a short blade runner blade that is provided in a flow path formed by the runner band, the flow straightening blade, and the adjacent runner blade, and has a blade length shorter than that of the runner blade. The distance between the runner blade and the runner band is B2, the distance between the runner blades at the blade inlet on the side formed by the runner band and the rectifying blade is L2, from the pressure surface of the runner blade When the distance to the suction surface of the blade runner blade is L22, the distance B2 between the rectifying blade and the runner band is set so as to satisfy 0.8 × L22 ≦ B2 ≦ 1.2 × L22 (2) It is characterized by that.

  According to a third aspect of the present invention, there is provided a runner crown attached to the main shaft, an annular runner band disposed at a position separated from the runner crown on an extension line of the main shaft center line, and the runner crown and runner band. A plurality of runner blades arranged at a predetermined pitch in the circumferential direction with respect to the flow path formed therebetween, and provided along the flow path between the runner crown and the runner band, and intersects each runner blade. And a short blade runner blade provided in a flow path formed by the runner crown, the flow straightening blade, and the adjacent runner blade, and having a blade length shorter than the runner blade. The distance between the runner blades at the runner blade inlet portion on the side to be formed is L1, and the distance from the pressure surface of the runner blade to the negative pressure surface of the short blade runner blade is L11 Then, an integer close to the value obtained by dividing the length of the outer periphery of the runner by L11 under the condition that 0.4 × L1 ≦ L11 ≦ 0.6 × L1 (3) is satisfied, It is characterized in that it is set as the number of blade runner blades.

  According to a fourth aspect of the present invention, there is provided a runner crown attached to the main shaft, an annular runner band disposed at a position spaced from the runner crown on an extension line of the main shaft center line, and the runner crown and runner band. A plurality of runner blades arranged at a predetermined pitch in the circumferential direction with respect to the flow path formed therebetween, and provided along the flow path between the runner crown and the runner band, and intersects each runner blade. And a short blade runner blade that is shorter than the runner blade, and is provided in a flow path formed by the runner band, the flow straightening blade, and the adjacent runner blade. When the distance between the runner blades at the blade inlet on the side to be formed is L2, and the distance from the pressure surface of the runner blade to the negative pressure surface of the short blade runner blade is L22, .4 × L2 ≦ L22 ≦ 0.6 × L2 (4) An integer close to the value obtained by dividing the length of the outer periphery of the runner by L22 under the condition that (4) is satisfied is calculated for the runner blade and the short blade runner blade. It is set as the number of blades.

  Further, the invention according to claim 5 includes a runner crown attached to the main shaft, an annular runner band disposed at a position spaced from the runner crown on an extension of the main shaft center line, and the runner crown and the runner band. A plurality of runner blades arranged at a predetermined pitch in the circumferential direction with respect to the flow path formed therebetween, and provided along the flow path between the runner crown and the runner band, and intersects each runner blade. And a short blade runner blade provided in a flow path formed by the runner crown, the flow straightening blade and the adjacent runner blade, and having a blade length shorter than the runner blade, the runner crown on the outer periphery side of the runner Is the distance between the runner blades and the runner blade pressure at the blade inlet on the side formed by the runner crown and the straightener blades. When the distance from the surface to the suction surface of the short blade runner blade is L11, the distance between the runner crown and the rectifying blade so as to satisfy 0.8 × L11 ≦ B1 ≦ 1.2 × L11 (1) An integer close to the value obtained by dividing the length of the outer periphery of the runner by L11 under the condition that B1 is set and 0.4 × L1 ≦ L11 ≦ 0.6 × L1 (3) is satisfied The number of blades of the runner blades and the short blade runner blades is set.

  Furthermore, the invention according to claim 6 includes a runner crown attached to the main shaft, an annular runner band disposed at a position spaced from the runner crown on an extension of the main shaft center line, and the runner crown and runner. A plurality of runner blades arranged at a substantially predetermined pitch in the circumferential direction with respect to the flow path formed between the bands, and provided along the flow path between the runner crown and the runner band, and each runner blade A rectifying blade on the outer peripheral side of the runner, comprising: a straightening vane that intersects; and a short vane runner blade that is provided in a flow path formed by the runner band, the straightening vane, and the adjacent runner vane, and has a blade length shorter than the runner vane. The distance between the vane and the runner band is B2, the distance between the runner vanes at the vane inlet on the side formed by the runner band and the rectifying vane is L2, and the runner vane pressure When the distance from the suction surface to the short blade runner blade is L22, the distance B2 between the rectifying blade and the runner band is set so as to satisfy 0.8 × L22 ≦ B2 ≦ 1.2 × L22 (2) An integer close to the value obtained by dividing the length of the outer periphery of the runner by L22 under the condition that 0.4 × L2 ≦ L22 ≦ 0.6 × L2 (4) is satisfied. And the number of blades of short blade runner blades.

  According to the present invention, runner blades are provided in the flow path between the runner crown and the runner band at a predetermined pitch in the circumferential direction, the straightening blades substantially parallel to the runner crown and the runner band are provided, and between the adjacent runner blades In a Francis hydraulic machine runner with short blade runner blades on the side, optimization of the position of the rectifying blades or optimization of the number of runner blades and short blade runner blades can further reduce hydraulic loss. It is possible to provide a Francis hydraulic machine and its runner that can be reduced.

Embodiments of a Francis hydraulic machine according to the present invention will be described below with reference to the drawings.
In addition, the overlapping description is abbreviate | omitted suitably by attaching | subjecting the same code | symbol to the part which is common in each figure, or adding the same code | symbol.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of a runner of a Francis-type hydraulic machine according to a first embodiment of the present invention, FIG. 1 (a) is a meridional section of a Francis-type turbine, and FIG. 1 (b) is a diagram of FIG. FIG.

  1 (a) and 1 (b), a runner (hereinafter simply referred to as a runner) 1 of the Francis hydraulic machine of this embodiment is attached to the lower end portion of a main shaft (not shown) and is formed in a substantially truncated cone shape. Between the runner crown 2, the annular runner band 3 arranged so as to be separated from the flow passage surface of the runner crown 2 by a predetermined distance on the extension line of the main shaft center line, and between the runner crown 2 and the runner band 3 And a plurality of runner blades 4 arranged at substantially equal pitches in the circumferential direction.

  Then, a rectifying blade 6 is provided so as to be substantially parallel to the flow path surfaces of the runner crown 2 and the runner band 3 and intersect with each of the plurality of runner blades 4, and further, the runner crown 2, the adjacent runner blade 4 and the rectifying blade A short blade runner blade 5 a having a blade length shorter than that of the runner blade 4 is provided in the flow path formed by the blade 6, and the flow path formed by the runner band 3, the adjacent runner blade 4 and the rectifying blade 6 is more than the runner blade 4. A short blade runner blade 5b having a short blade length is provided. In the following, for convenience of explanation, the runner blade 4, that is, the runner blade 4 having a normal blade length is referred to as a long blade 4, and the short blade runner blade 5 a having a blade length shorter than that of the normal blade length runner blade 4, 5b is called short blade 5a, 5b.

The present embodiment is characterized in that in the runner of the Francis-type hydraulic machine configured as described above, the rectifying blades 6 are arranged in a range satisfying the following formula (1) or formula (2).
0.8 × L11 ≦ B1 ≦ 1.2 × L11 (1)
0.8 × L22 ≦ B2 ≦ 1.2 × L22 (2)
here,
B: Blade height on the runner 1 inlet side (runner 1 outer periphery side),
B1; distance between the runner crown 2 and the rectifying blade 6;
B2: distance between the rectifying blade 6 and the runner band 3;
L1; distance between adjacent long blades 4 at the blade inlet portion on the side formed by the runner crown 2 and the rectifying blade 6;
L2: distance between the long blades 4 at the blade inlet portion on the side formed by the runner band 3 and the rectifying blade 6;
L11: Distance from the pressure surface side of the long blade 4 to the suction surface of the adjacent short blade 5a in the direction opposite to the rotation direction of the runner 1,
L22: distance from the pressure surface of the long blade 4 to the suction surface of the short blade 5a in the direction opposite to the rotation of the runner,
And

  When the above formula (1) or formula (2) is satisfied, the pressure surfaces of the runner crown 2, the rectifying blade 6, the runner band 3, and the adjacent long blades 4 as shown in the X arrow view of FIG. The rectangular flow path formed by the suction surfaces of the short blades 5a and 5b has a shape with an aspect ratio close to 1: 1.

  FIG. 4 shows the runner crown 2 and the rectifying blade 6 during overload operation (when the flow rate is higher than the design point) when the distance B1 between the runner crown 2 and the rectifying blade 6 is changed at the inlet of the runner 1. FIG. 5 is a diagram showing a change in secondary flow loss that occurs in a region formed between the pressure surface of the long blade 4 and the suction surface of the short blade 5a.

  Here, the secondary flow is a loss component due to the secondary flow from the rectifying blade 6 side toward the runner crown 2 side, a loss due to the secondary flow component from the pressure surface of the long blade 4 toward the suction surface, and these two loss components. Shows the combined loss.

  Generally, in an overload operation state, the secondary flow component from the runner band 3 side to the runner crown 2 side increases, and hydraulic loss increases. This secondary flow can be reduced by providing the rectifying blade 6, but by providing the short blade 5 a between the long blades 4, the secondary flow component from the blade pressure surface to the suction surface can also be reduced. It becomes possible to reduce.

  When the distance B1 between the runner crown 2 and the rectifying blade 6 is increased, the secondary flow loss in the direction of the rectifying blade 6 from the runner crown 2 side is increased, and conversely, when the distance B1 is small, the pressure of the long blade 4 is relatively increased. The secondary flow loss from the surface toward the suction surface of the short blade 5a increases. When these secondary flow losses are added together, it can be seen that the distance B1 between the runner crown 2 and the rectifying blade 6 is small in the range satisfying the above-mentioned formula (1).

  FIG. 5 shows the runner band 3, the rectifying blade 6, It is the figure which showed the change of the secondary flow loss generate | occur | produced in the area | region formed between the pressure surface of the long blade 4, and the negative pressure surface of the short blade 5b.

  In general, during partial load operation, the secondary flow loss from the runner crown 2 side toward the runner band 3 side increases, but this can also be reduced by arranging the rectifying blades 6. Further, by providing the short blades 5b between the long blades 4, the secondary flow from the blade pressure surface of the long blades 4 to the negative pressure surface of the short blades 5b can be reduced.

  When the distance B2 between the rectifying blade 6 and the runner band 3 is increased, the secondary flow loss in the direction of the runner band 3 from the rectifying blade 6 side is increased. Conversely, when the distance B2 is small, the long blade 4 The secondary flow loss from the pressure surface toward the suction surface of the short blade 5b increases. When these secondary flow losses are added together, it can be seen that the distance B2 between the rectifying blades 6 and the runner band 3 has a small loss within a range satisfying the above-mentioned formula (2).

  Therefore, when the position of the rectifying blade 6 is arranged in a range that satisfies L11 in the formula (1) or L22 in the formula (2), it is possible to effectively suppress the occurrence of hydraulic loss in overload operation or partial load operation. It becomes.

  As described above, when the position of the rectifying blade 6 is arranged so as to satisfy the above formula (1) or formula (2), it has been explained that the occurrence of hydraulic loss can be effectively suppressed during overload operation or partial load operation. However, the following explains that the hydraulic loss can be more effectively suppressed by adjusting the number of the long blades 4 and the short blades 5a and 5b.

FIG. 6 is a diagram showing a secondary flow loss distribution in the circumferential direction in a region formed by the rectifying blade 6, the runner crown 2, and the long blade 4 when the circumferential position of the short blade 5 a is changed. is there.
In FIG. 6, the secondary flow loss from the pressure surface of the long blade 4 to the suction surface of the short blade 5a has a gentle slope with the increase of L11 from the initial L11 zero to a distance slightly exceeding 0.4L1. It increases, but increases with a steep slope from around 0.5L1. On the other hand, the secondary flow loss from the pressure surface of the short blade 5a to the suction surface of the long blade 4 is maximum at the position where L11 is zero, and decreases in inverse proportion as L11 increases, to L1. Then it becomes zero. When looking at the total loss obtained by adding these two losses, the distance L11 from the pressure surface side of the long blade 4 to the negative pressure surface of the adjacent short blade 5a is 0 in the direction opposite to the rotation direction of the runner 1. It can be seen that the total loss is small when it is in the range of 4L1 to 0.6L1.

From the above relationship, the following equation (3) is derived.
0.4 × L1 ≦ L11 ≦ 0.6 × L1 (3)
If an integer close to the value obtained by dividing the length of the outer periphery of the runner by L11 under the condition that the expression (3) is satisfied is the number of blades of the long blade 4 and the short blade 5a, the runner crown 2, the rectifying blade 6 The hydraulic loss can be effectively suppressed even in the region formed between the long blade 4 suction surface and the short blade 5a pressure surface.

On the other hand, FIG. 7 is a diagram showing a secondary flow loss distribution in the circumferential direction in a region formed by the rectifying blade 6, the runner band 3, and the long blade 4 when the circumferential position of the short blade 5b is changed. is there.
In FIG. 7, the secondary flow loss from the pressure surface of the long blade 4 to the suction surface of the short blade 5b has a gentle slope with increasing L22 until the distance at which the initial L22 slightly exceeds 0.4L2. However, it increases with a steep slope from around 0.5L2. On the other hand, the secondary flow loss from the pressure surface of the short blade 5b to the suction surface of the long blade 4 is maximum at the position where L22 is zero, and decreases in inverse proportion as L22 increases to L2. Then it becomes zero. Then, looking at the total loss obtained by adding these two losses, it can be seen that the total loss is small when L22 is in the range of 0.4L2 to 0.6L2.

From the above relationship, the following equation (4) is derived.
0.4 × L2 ≦ L22 ≦ 0.6 × L2 (4)
If an integer close to the value obtained by dividing the length of the outer periphery of the runner by L22 under the condition that the expression (4) is satisfied is the number of blades of the long blade 4 and the short blade 5b, the runner band 3 and the rectifying blade 6 The hydraulic loss can be effectively suppressed even in the region formed between the long blade 4 suction surface and the short blade 5a pressure surface.

  As described above, according to the first embodiment, the runner blades are provided in the flow path between the runner crown and the runner band at a predetermined pitch in the circumferential direction, and the straightening blades substantially parallel to the runner crown and the runner band are provided. In addition, in the runner of Francis hydraulic machines with short blade runner blades between adjacent runner blades, the position of the rectifying blades is optimized, and the number of long blades and short blades is optimized. By doing so, it is possible to reduce hydraulic power loss particularly at non-design points.

(Second Embodiment)
FIG. 2 is a schematic cross-sectional view of a runner of a Francis-type hydraulic machine showing a second embodiment of the present invention. FIG. 2A is a meridional section of the Francis-type hydraulic machine, and FIG. FIG.

  The runner of the Francis hydraulic machine of this embodiment is different from the runner of the Francis hydraulic machine of the first embodiment as shown in FIGS. 2 (a) and 2 (b). Except that the short blade 5a between the runner band 3 and the rectifying blade 6 is omitted, except for the short blade 5a between them. The other configurations are the same as those in the first embodiment. is there.

Therefore, in the case of the present embodiment, the reduction of the secondary flow loss can be described with reference to FIGS. 4 and 6. For the position adjustment of the rectifying blade 6, the above formula (1) is used, and the long blade For the adjustment of the number of 4 and the short blades 5a, the above-described formula (3) can be applied.
0.8 × L11 ≦ B1 ≦ 1.2 × L11 (1)
0.4 × L1 ≦ L11 ≦ 0.6 × L1 (3)

  As a result, it is possible to effectively suppress the occurrence of hydraulic loss in overload operation by positioning the rectifying blade 6 at 0.8 × L11 ≦ B1 ≦ 1.2 × L11 (1). In addition, an integer close to the value obtained by dividing the length of the outer periphery of the runner by L11 under the condition that 0.4 × L1 ≦ L11 ≦ 0.6 × L1 (3) is satisfied, By adjusting the number of blades of the short blade 5a, hydraulic loss can be reduced even in the region formed between the runner crown 2, the rectifying blade 6, the long blade 4 suction surface and the pressure surface of the short blade 5a. Hydraulic loss can be effectively suppressed.

  As described above, according to the present embodiment, as in the first embodiment, by optimizing the position of the rectifying blades and further optimizing the number of long blades and short blades, it is possible to improve the design of the non-design points. The hydraulic power loss at can be reduced.

(Third embodiment)
FIG. 3 is a schematic cross-sectional view of a runner of a Francis-type hydraulic machine showing a third embodiment of the present invention, FIG. 3 (a) is a meridional section of a Francis-type turbine, and FIG. 3 (b) is FIG. 3 (a). FIG.

  The runner of the Francis-type hydraulic machine of the present embodiment is different from the runner of the Francis-type hydraulic machine of the first embodiment as shown in FIGS. 3 (a) and 3 (b). Except that the short blade 5b between the runner crown 2 and the rectifying blade 6 is omitted, except for the short blade 5b between them. The other configurations are the same as those in the first embodiment. is there.

Therefore, in the case of the present embodiment, the reduction of the secondary flow loss can be described with reference to FIGS. 5 and 7, and the position adjustment of the rectifying blade 6 can be performed using the above formula (2) and the long blades. For the adjustment of the number of 4 and the short blades 5b, the above-described equation (4) can be applied.
0.8 × L22 ≦ B2 ≦ 1.2 × L22 (2)
0.4 × L2 ≦ L22 ≦ 0.6 × L2 (4)

  As a result, it is possible to effectively suppress the occurrence of hydraulic loss in overload operation by positioning the rectifying blade 6 at 0.8 × L22 ≦ B2 ≦ 1.2 × L22 (2). In addition, an integer close to the value obtained by dividing the length of the outer periphery of the runner by L22 under the condition that 0.4 × L2 ≦ L22 ≦ 0.6 × L2 (4) is satisfied, By adjusting the number of blades of the short blade 5b, hydraulic loss can be reduced even in the region formed between the runner band 3, the rectifying blade 6, the long blade 4 suction surface, and the pressure surface of the short blade 5b. Hydraulic loss can be effectively suppressed.

  As described above, according to the present embodiment, as in the first embodiment, by optimizing the position of the rectifying blades and further optimizing the number of long blades and short blades, it is possible to improve the design of the non-design points. The hydraulic power loss at can be reduced.

It is a schematic cross section of the runner of the Francis type hydraulic machine which shows the 1st Embodiment of this invention, Fig.1 (a) is a meridian cross section of the runner of a Francis type hydraulic machine, FIG.1 (b) is FIG.1 (a). X arrow view. It is a schematic cross section of the runner of the Francis type hydraulic machine which shows the 2nd Embodiment of this invention, Fig.2 (a) is a meridional section of the runner of a Francis type hydraulic machine, FIG.2 (b) is FIG.2 (a). X arrow view. It is a schematic cross section of the runner of the Francis type hydraulic machine which shows the 3rd Embodiment of this invention, Fig.3 (a) is a meridian cross section of the runner of a Francis type hydraulic machine, FIG.3 (b) is FIG.3 (a). X arrow view. The correlation figure of the position of the hydraulic loss and the rectifying blade in the first and second embodiments. The correlation figure of the hydraulic loss and the position of a rectifying blade in 1st and 3rd embodiment. FIG. 5 is a correlation diagram between hydraulic loss and short blade position in the first and second embodiments. The correlation figure of the hydraulic loss and short blade position in the 1st and 3rd embodiment. The schematic diagram of the runner of the conventional Francis type hydropower machine. Schematic diagram of meridional flow in the runner depending on the amount of water. The schematic diagram of the runner meridional shape of the conventional Francis type hydropower machine. The schematic diagram of the runner of the Francis type hydraulic machine which has the blade | wing of the conventional several different shape.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... runner, 2 ... runner crown, 3 ... runner band, 4 ... runner blade (long blade), 5a, 5b ... runner blade (short blade), 6 ... rectifying blade, 7 ... casing, 8 ... stay vane, 9 ... Guide vane, 10 ... suction pipe, 11 ... main shaft, 12 ... generator, 14 ... dynamic pressure of water flow, 15 ... runner rotation centrifugal force, 16 ... dead water region.

Claims (7)

A runner crown attached to the spindle,
An annular runner band disposed at a position spaced from the runner crown on an extension of the main axis of the spindle;
A plurality of runner blades arranged at a substantially predetermined pitch in the circumferential direction with respect to the flow path formed between the runner crown and the runner band;
A rectifying blade provided along the flow path between the runner crown and the runner band, and intersecting each runner blade,
A short blade runner blade provided in a flow path formed by the runner crown, the rectifying blade and the adjacent runner blade, and having a blade length shorter than the runner blade;
The distance between the runner crown on the outer peripheral side of the runner and the straightening blade is B1, the distance between the runner blades at the runner blade inlet portion formed by the runner crown and the straightening blade is L1, and the short blade runner blade from the pressure surface of the runner blade A runner for a Francis hydraulic machine, wherein the distance B1 between the runner crown and the rectifying blades is set so as to satisfy the following formula (1), where L11 is the distance to the suction surface.
0.8 × L11 ≦ B1 ≦ 1.2 × L11 (1) A runner crown attached to the spindle,
An annular runner band disposed at a position spaced from the runner crown on an extension of the main axis of the spindle;
A plurality of runner blades arranged at a substantially predetermined pitch in the circumferential direction with respect to the flow path formed between the runner crown and the runner band;
A rectifying blade provided along the flow path between the runner crown and the runner band, and intersecting each runner blade,
A short blade runner blade provided in a flow path formed by the runner band, the rectifying blade and the adjacent runner blade, and having a blade length shorter than the runner blade,
The distance between the rectifier blade on the outer peripheral side of the runner and the runner band is B2, the distance between the runner blades at the blade inlet portion on the side formed by the runner band and the rectifier blade is L2, and from the pressure surface of the runner blade to the short blade runner blade A runner for a Francis hydraulic machine, wherein the distance B2 between the rectifying blades and the runner band is set so as to satisfy the following formula (2) when the distance to the suction surface is L22.
0.8 × L22 ≦ B2 ≦ 1.2 × L22 (2) A runner crown attached to the spindle,
An annular runner band disposed at a position spaced from the runner crown on an extension of the main axis of the spindle;
A plurality of runner blades arranged at a substantially predetermined pitch in the circumferential direction with respect to the flow path formed between the runner crown and the runner band;
A rectifying blade provided along the flow path between the runner crown and the runner band, and intersecting each runner blade,
A short blade runner blade provided in a flow path formed by the runner crown, the rectifying blade and the adjacent runner blade, and having a blade length shorter than the runner blade;
When the distance between the runner blades at the runner blade inlet portion on the side formed by the runner crown and the rectifying blade is L1, and the distance from the pressure surface of the runner blade to the negative pressure surface of the short blade runner blade is L11, An integer close to the value obtained by dividing the length of the outer periphery of the runner by L11 under the condition that (3) is satisfied is set as the number of blades of the runner blades and the short blade runner blades. Lanna.
0.4 × L1 ≦ L11 ≦ 0.6 × L1 (3) A runner crown attached to the spindle,
An annular runner band disposed at a position spaced from the runner crown on an extension of the main axis of the spindle;
A plurality of runner blades arranged at a substantially predetermined pitch in the circumferential direction with respect to the flow path formed between the runner crown and the runner band;
A rectifying blade provided along the flow path between the runner crown and the runner band, and intersecting each runner blade,
A short blade runner blade provided in a flow path formed by the runner band, the rectifying blade and the adjacent runner blade, and having a blade length shorter than the runner blade,
When the distance between the runner blades at the blade inlet portion on the side formed by the runner band and the rectifying blade is L2, and the distance from the pressure surface of the runner blade to the negative pressure surface of the short blade runner blade is L22, the following formula ( 4) A runner for a Francis hydraulic machine characterized in that an integer close to the value obtained by dividing the length of the outer periphery of the runner by L22 under the condition 4) is set as the number of runner blades and short blade runner blades. .
0.4 × L2 ≦ L22 ≦ 0.6 × L2 (4) A runner crown attached to the spindle,
An annular runner band disposed at a position spaced from the runner crown on an extension of the main axis of the spindle;
A plurality of runner blades arranged at a substantially predetermined pitch in the circumferential direction with respect to the flow path formed between the runner crown and the runner band;
A rectifying blade provided along the flow path between the runner crown and the runner band, and intersecting each runner blade,
A short blade runner blade provided in a flow path formed by the runner crown, the rectifying blade and the adjacent runner blade, and having a blade length shorter than the runner blade;
The distance between the runner crown on the outer periphery side of the runner and the flow straightening blade is B1, the distance between the runner blades at the blade inlet on the side formed by the runner crown and the flow straightening blade is L1, and When the distance to the suction surface is L11, the distance B1 between the runner crown and the rectifying blade is set so as to satisfy the following equation (1), and the condition of the outer periphery of the runner is satisfied under the condition that the following equation (3) is satisfied. A runner for a Francis hydraulic machine, wherein an integer close to the value obtained by dividing the length by L11 is set as the number of blades of the runner blades and the short blade runner blades.
0.8 × L11 ≦ B1 ≦ 1.2 × L11 (1)
0.4 × L1 ≦ L11 ≦ 0.6 × L1 (3) A runner crown attached to the spindle,
An annular runner band disposed at a position spaced from the runner crown on an extension of the main axis of the spindle;
A plurality of runner blades arranged at a substantially predetermined pitch in the circumferential direction with respect to the flow path formed between the runner crown and the runner band;
A rectifying blade provided along the flow path between the runner crown and the runner band, and intersecting each runner blade,
A short blade runner blade provided in a flow path formed by the runner band, the rectifying blade and the adjacent runner blade, and having a blade length shorter than the runner blade,
The distance between the rectifier blades on the outer periphery of the runner and the runner band is B2, the distance between the runner blades at the blade inlet on the side formed by the runner band and the rectifier blades is L2, and from the pressure surface of the runner blade to the short blade runner blade When the distance to the suction surface is L22, the distance B2 between the rectifying blade and the runner band is set so as to satisfy the following equation (2), and the condition of the outer periphery of the runner is satisfied under the condition that the following equation (4) is satisfied. A runner for a Francis hydraulic machine, wherein an integer close to the value obtained by dividing the length by L22 is set as the number of blades of the runner blades and the short blade runner blades.
0.8 × L22 ≦ B2 ≦ 1.2 × L22 (2)
0.4 × L2 ≦ L22 ≦ 0.6 × L2 (4)   A Francis-type hydraulic machine comprising the Francis-type hydraulic machine runner according to any one of claims 1 to 6.

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