JP2011174474A - Hydraulic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic apparatus that suppresses cavitation generated in the operation of a runner, and also facilitates operations of manufacturing work and maintenance check for the apparatus. <P>SOLUTION: The apparatus includes a runner 14 with an intermediate vane, wherein a long vane 12 and a short vane 13 are disposed alternately along in a circumferential direction. A location where a vane thickness of the vane 13 is the largest, is configured to be located on an entrance side from the middle point in the vane length from the entrance to the exit of the vane 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hydraulic machine in which short blades are arranged between long blades arranged in a circumferential direction of a runner.

  Conventionally, in a hydraulic machine, for example, a Francis type pump turbine, runner vanes 2 are arranged on the runner 1 at equal intervals in the circumferential direction as shown in FIG.

  Recently, for the purpose of improving the turbine partial load characteristics due to the flow rectification effect and the improvement of the pump characteristics accompanying the reduction of the slippage in the pump flow, the arrangement of the runner vanes 2 is long as shown in FIG. A so-called runner 5 with intermediate blades in which the blades 3 and the short blades 4 are alternately arranged in the circumferential direction has been proposed.

  Further, for example, Japanese Patent Application Laid-Open No. 60-50274 (Patent Document 1) is known as this type of runner. This runner has a structure having an outer peripheral runner vane that is an integral multiple of the inner peripheral runner vane on the outer peripheral side of the inner peripheral runner vane at equal angular intervals.

  Further, another runner of the same type is known, for example, in Japanese Patent Application Laid-Open No. 57-126666 (Patent Document 2). In this runner, a plurality of runner vanes are arranged at a predetermined pitch in the circumferential direction in the inlet-side flow path between the runner crown and the runner band, shorter than the runner vane blade length, and substantially parallel to the runner vanes. One or more intermediate vanes are arranged.

  In such a runner, it is possible to suppress the disturbance of the three-dimensional water flow on the inlet side in the conventional runner having a small number of vanes, and to reduce the blade load per vane and improve the rectification effect. Thus, the pressure reduction on the blade suction surface can be prevented, and the conversion efficiency from power water to power and the cavitation performance can be improved.

Japanese Patent Laid-Open No. 60-50274 JP-A-57-126666

  By the way, the runner 5 with intermediate wings in which the long wings 3 and the short wings 4 shown in FIG. 13 are arranged alternately is almost the same as the long wing 3 except that the short wings 4 are shorter than the long wings 3. It is considered to be a shape. For this reason, as shown in FIG. 14, the blade length is different between the long blade 3 and the short blade 4, and the circulation strengths Γa and Γb around the blade surface are also different. That is, since the blade load determined by the difference between the pressure on the working surface and the pressure on the reaction surface is different between the long blade 3 and the short blade 4, the distribution of vorticity generated around the blade surface is different. Therefore, even if the flow of the water flow W flowing into the runner is the same, the inflow angles αa and αb of the local water flows W1 and W2 near the blades to the blades are naturally different depending on the long blade 3 and the short blade 4. In particular, it is conceivable that the short blade has a short blade length, so that a sufficient pressure is not applied to the working surface. As a result, the circulation Γb is weakened, so that the local water flow W2 inflow angle near the inlet of the short blade 4 is obtained. It is conceivable that αb is smaller than the inflow angle αa of the local water flow W1 in the vicinity of the inlet of the long blade 3. When the inflow angle to the blade is small, cavitation CAV is likely to occur in the vicinity of the blade inlet on the working surface side, and when this is significant, large flow separation occurs at the blade inlet, which may cause performance degradation.

  FIG. 15 shows a conventional runner 5 with an intermediate blade as viewed vertically upward from the runner outlet lower side. In the following, when simply referred to as “runner inlet” or “runner outlet”, it indicates an inlet and an outlet when a water turbine is operated. That is, “runner inlet side” and “runner outlet side” are the outlet side and the inlet side of the water flow, respectively, during pump operation. The exit edge 8a that connects the crown 6 side of the short blade 4 and the band 7 side of the runner 5 with intermediate blades is the center of rotation of the runner 5 with intermediate blade from the inner peripheral side to the outer peripheral side in the same manner as the outlet edge 8b of the long blade 3. It extends radially from the center O of the rotating shaft 9. For this reason, the blade length of the short blade 4 is uniformly shorter than the long blade 3 from the crown 6 side to the band 7 side. That is, the extended lines of the outlet edges 8a and 8b of the long blade 3 and the short blade 4 are configured to intersect at an angle θ at the center O in FIG. 15, in other words, the rotation axis of the runner 5 with intermediate blades. On the projection plane perpendicular to each other, the outlet edges 8a and 8b of the respective blades are arranged on a straight line connecting the rotation center of the runner 5 with the intermediate blade and the crown 6 side ends of the long blade 3 and the short blade 4 outlet. ing. In this case, the ratio of the blade length of the short blade 4 to the blade length of the long blade 3 is smaller on the band 7 side than on the crown 6 side. The blade length of the short blade 4 is relatively shorter on the band 7 side than on the crown 6 side, and this causes cavitation CAV at the short blade inlet portion shown in FIG. It becomes easy to do. Further, during the pump operation, the blade length of the short blade 4 is relatively short, so that a considerable load is applied on the band 7 side of the long blade 3.

  Conventionally, the Francis pump turbine runner has an equal thickness from the inlet side to the outlet side from the viewpoint of strength, manufacturing and cost. Accordingly, the short blade 4 of the runner 5 with intermediate blades may have the same thickness structure as the long blade 3. In the intermediate bladed runner 5 in which the number of blades is larger than that of a normal runner, the flow path between the blades becomes narrow as the number of blades increases and the blade thickness structure is equal. If the flow path between the blades becomes narrower, when operating on the overload side from the maximum efficiency point, the water flow rate increases and the efficiency decreases due to increased friction, etc. In addition, due to the narrowing of the flow path, there are various inconveniences and problems in workability in terms of production and maintenance.

  The present invention has been made based on such circumstances, and provides a hydraulic machine that suppresses cavitation that occurs during operation of the runner and that facilitates the work in terms of production and maintenance. Objective.

  In order to achieve the above-described object, the hydraulic machine according to the present invention is a hydraulic machine including a runner with intermediate blades in which long blades and short blades are alternately arranged along a circumferential direction. The maximum position is set on the inlet side rather than half of the blade length from the inlet to the outlet of the short blade.

  Further, in order to achieve the above-mentioned object, the hydraulic machine according to the present invention is a hydraulic machine including a runner with intermediate blades in which long blades and short blades are alternately arranged along a circumferential direction. The thickness is formed to be smaller than the blade thickness of the long blade between the overlap between the short blade and the long blade adjacent to the working surface side of the short blade.

  The hydraulic machine according to the present invention can reduce the difference in blade load between the long blades and the short blades by increasing the blade width between the long blades and the short blades of the runner with intermediate blades. While suppressing inlet cavitation and flow separation, it is possible to maintain a stable operation by shifting the backflow limit to the small flow rate side during the pump high head operation of the long blades.

  Further, the hydraulic machine according to the present invention can further improve the hydraulic efficiency by widening the flow path width between the long blade and the short blade of the runner with intermediate blades, and further improve the production and maintenance inspections. Workability can be facilitated.

FIG. 3 is a schematic half-molecular meridional cross-sectional view showing a runner with an intermediate blade in the hydraulic machine according to the present invention. FIG. 2 is a partially cutaway partial view seen from the direction of arrow A in FIG. 1. The pressure distribution diagram added to each action surface and reaction surface of the long blade of a conventional runner with an intermediate blade, and a short blade. The pressure distribution diagram added to each action surface and reaction surface of the long blade and short blade of the runner with an intermediate blade in the hydraulic machine which concerns on this invention. The diagram which contrasted the cavitation characteristic in each inlet_port | entrance of the conventional runner with an intermediate blade and the runner with an intermediate blade which concerns on this invention. Schematic which shows 2nd Embodiment of the hydraulic machine which concerns on this invention. The diagram which contrasted the pressure distribution added to the action surface and reaction surface of the long blade of the conventional runner with an intermediate blade, and the pressure distribution applied to the action surface and reaction surface of the long blade of the runner with an intermediate blade according to the present invention. The partially cutaway partial cross-sectional view showing a third embodiment of the hydraulic machine according to the present invention. The partially cutaway partial sectional view showing a fourth embodiment of the hydraulic machine according to the present invention. In 5th Embodiment of the hydraulic machine which concerns on this invention, the diagram which shows the blade surface pressure distribution on a central streamline at the time of the water turbine driving | running | working of the runner with an intermediate blade. In 5th Embodiment of the hydraulic machine which concerns on this invention, the partial notch partial sectional drawing used in order to demonstrate the blade | wing thickness of the long blade and short blade on the central streamline of a runner with an intermediate blade. Schematic which shows the conventional runner without an intermediate blade. Schematic which shows the conventional runner with an intermediate blade. The figure used in order to explain the flow of the water flow near the entrance of the conventional runner with an intermediate wing. The figure which looked at the conventional runner with an intermediate wing from the runner exit lower part perpendicularly upward.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a hydraulic machine according to the present invention will be described with reference to the drawings and reference numerals attached to the drawings.

  1 and 2 are schematic views showing a first embodiment of a hydraulic machine according to the present invention, taking a Francis pump turbine as an example. FIG. 1 is a schematic half-molecular cross-sectional partial view showing a runner with an intermediate blade in a hydraulic machine according to the present invention. FIG. 2 is a partially cutaway partial view seen from the direction of arrow A in FIG.

  A hydraulic machine according to the present embodiment, for example, a Francis type pump turbine, is supported by a runner 14 with intermediate blades in which both ends are supported by a crown 10 and a band 11 and long blades 12 and short blades 13 are alternately arranged in the circumferential direction. It has become.

  In the runner 14 with the intermediate blade, when the intersections of the outlet edge 15 of the short blade 13 on the band 11 side and the crown 10 side are 16 and 17, the position of the intersection 16 on the band 11 side is the outlet side of the short blade 13. The short blade lower-side imaginary line 20 connecting the intersection 16 on the band 11 side and the center O of the rotation axis (main axis) 18 connects the intersection 17 on the crown 10 side and the center O of the rotation axis 18. The short blade 13 is configured so as to be closer to the outlet side of the short blade 13 by an angle θa on the projection plane perpendicular to the rotation axis than the short blade top side virtual line 19.

  That is, in this embodiment, as shown in FIG. 2, when the runner 14 with the intermediate blade is viewed vertically upward from the lower side of the runner outlet, the outlet edge 15 of the short blade 13 is arranged radially from the center of the runner 14. In other words, the extension line of the outlet edge 15 does not pass through the center O of the rotating shaft 18. The exit edge 15 has a shape in which the intersection 16 side serving as the end portion on the band 11 side protrudes from the exit side of the short blade 13 rather than the intersection 17 side serving as the end portion on the crown 10 side. The band 11 side of the short blade 13 is longer than the conventional runner 5 with intermediate blade shown in FIG.

  FIG. 3 is a graph showing the pressure distribution around the blades on the band 7 side during the water turbine operation of the short blades 4 and the long blades 3 of the conventional runner 5 with intermediate blades shown in FIG. In the figure, the broken line indicates the pressure distribution of the short blade 4, and the solid line indicates the pressure distribution of the long blade 3. Here, with respect to the short blade 4 and the long blade 3, the upper lines indicate the pressure distribution on the working surface (ie, the pressure surface), and the lower line indicates the pressure distribution on the reaction surface (the negative pressure surface). Is shown. The result of integrating the pressure difference between the working surface and the reaction surface from the inlet side to the outlet side of each blade indicates the blade loads of the short blade and the long blade at this position (band 7 side).

  According to FIG. 3, when the conventional runner 5 with intermediate blades shown in FIG. 15 is operated in a water turbine, the pressure difference between the long blades 3 and the short blades 4 is significantly different on the inlet side on the band 7 side. In addition, at the inlet portion of the short blade 4, the pressure on the working surface is lower than the pressure on the reaction surface, and it can be seen that no effective load is received. In particular, since there is a low pressure portion on the working surface side of the inlet portion, cavitation may occur at the inlet portion of the working surface of the short blade 4 due to fluctuations in the operation state of the water turbine, and the cavitation performance of the short blade 4 is reduced. You can see that

  On the other hand, FIG. 4 shows the runner 14 with the intermediate blade of the present embodiment shown in FIGS. 1 and 2, as in FIG. It is a graph which shows pressure distribution. Here, also in FIG. 4, as in FIG. 3, the solid line indicates the pressure distribution of the long blade 12, and the broken line indicates the pressure distribution of the short blade 13.

  Comparing FIG. 4 with FIG. 3, it can be seen that in FIG. 4, the pressure difference between the working surface and the reaction surface increases on the inlet side of the short blade 13 and is almost the same as that of the long blade 12. In addition, the blade load is increased by extending the length of the short blade 13 on the band 11 side. Conversely, the blade load of the long blade 12 is reduced, and both the long blade 12 and the short blade 13 are effective with substantially equal blade loads. You can see that you are working. Further, since the blade load of the long blade 12 is reduced, the cavitation performance on the outlet side of the long blade 12 (that is, the inlet side of the water flow during the pump operation) during pump operation on the high head side (small flow rate). Can also be improved.

  Further, since the short blade 13 is extended to the outlet side and the load on the short blade 13 is increased, the phenomenon that the pressure on the working surface falls below the pressure on the reaction surface on the inlet side of the short blade 13 does not occur. . This is considered to be because the circulation around the short blade 13 is strengthened by increasing the load of the short blade 13 and water flows in at a sufficient angle on the inlet side. The characteristics are good.

  FIG. 5 shows a comparison between a head during turbine operation and an operation range based on turbine output for the conventional runner with intermediate blade 5 shown in FIG. 15 and the runner 14 with intermediate blade according to the present embodiment shown in FIG. FIG. Here, these turbines are operated so that the maximum output at that time falls below Ptmax between the heads Htmin and Htmax, and the curves shown by the solid line and the broken line are those of this embodiment. The cavitation generation limit of the water turbine using the runner 14 with the intermediate wing and the turbine using the conventional runner 5 with the intermediate wing shown in FIG. 15 are shown, and the operation of the water turbine is performed within the range surrounded by these lines. It represents what you can do. That is, as is clear from FIG. 5, in the water turbine using the intermediate bladed runner 14 of the present embodiment, the cavitation generation limit is on the lower output side with respect to all operable heads, and the operation range is You can see that it is more widespread. That is, as described above, when this embodiment is used, a sufficient blade load is applied to the short blade 13 of the runner 14 with intermediate blades even in a low output operation, so that sufficient circulation around the blade is obtained. Since the local inflow angle of water to the short blade 13 at the blade inlet can be increased, effective work can be performed on the short blade 13 without generating cavitation.

  Further, if the blade load is the same as that of the conventional runner 14 with the intermediate blade as the entire runner 14 with the intermediate blade, considering the balance of the blade load, the crown 10 side of the short blade 12 is more than the conventional runner with the intermediate blade. It can be shortened, and workability in terms of production and maintenance can be improved.

  In the runner 14 with intermediate blades according to the present embodiment shown in FIG. 2, the outlet edge 15 of the short blade 13 is linear from the band 11 side to the crown 10 side, but may be a smooth curve. . By making the outlet edge 15 of the short blade 13 a smooth curve and adjusting the angle θa, the blade load of the short blade 13 can be finely adjusted, and the cavitation performance and the like can be set optimally. In this way, the flow path width formed by the long blades 12 and the short blades 13 can be finely adjusted from the band 11 side to the crown 10 side, so that the outlet flow of the intermediate bladed runner 14 during water turbine operation There is an advantage that can be made uniform.

  As described above, in the present embodiment, the exit edge 15 of the short blade 13 with respect to the short blade top-side imaginary line 19 that connects the intersection 17 on the crown 10 side of the exit edge 15 of the short blade 13 and the center O of the rotating shaft 18. The short blade imaginary line 20 connecting the intersection 16 on the band 11 side and the center O of the rotating shaft 18 protrudes to the exit side of the short blade 13 by an angle θa on the projection plane perpendicular to the rotating shaft of the runner. Since the exit edge 15 of the short blade 13 is provided in the cavitation performance, the cavitation performance can be improved and the load on the long blade 12 and the short blade 13 can be made uniform. Further, with such a configuration, the flow path width between the long blades 12 and the short blades 13 can be finely adjusted, so that work such as maintenance and inspection can be facilitated.

  FIG. 6 is a schematic view showing a second embodiment of the hydraulic machine according to the present invention, taking a Francis pump turbine as an example. In addition, the same code | symbol is attached | subjected to the same part as the component of 1st Embodiment.

  A hydraulic machine according to the present embodiment, for example, a runner 14 with an intermediate blade of a Francis-type pump turbine, when the crossing points 22 and 23 of the outlet edge 21 of the long blade 12 are on the band 11 side and the crown 10 side, respectively. The position of the crossing point 23 is moved to the outlet side of the long blade 12, and the long blade low-side imaginary line 24 connecting the crossing point 22 on the band 11 side and the center O of the rotation axis (main shaft) 18 is on the crown 10 side. The long blade top side imaginary line 25 connecting the intersection 23 of the rotation axis 18 and the center O of the rotating shaft 18 is configured to be on the exit side of the long blade 12 by an angle θb on the projection plane perpendicular to the rotating shaft.

  That is, in this embodiment, as shown in FIG. 6, when the runner 14 with intermediate blades is viewed vertically upward from the bottom of the runner outlet, the outlet edge 21 of the long blade 12 is arranged radially from the center of the runner 14. The extension line of the outlet edge 21 does not pass through the center O of the rotating shaft 18. The exit edge 21 has a shape in which the intersection 22 side serving as the end portion on the band 11 side protrudes from the exit side of the long blade 12 rather than the intersection 23 side serving as the end portion on the crown 10 side. The band 11 side of the long blade 12 is longer than the conventional runner 5 with an intermediate blade shown in FIG.

  FIG. 7 shows the blade circumference on the band 7 side during pump operation for the long blade 3 of the conventional runner 5 with intermediate blade shown in FIG. 15 and the long blade 12 and short blade 13 of the runner 14 with intermediate blade of the present embodiment. It is a graph which shows pressure distribution of. In the figure, the solid line indicates the pressure distribution of the long blade 12 to which the present embodiment is applied, the broken line indicates the pressure distribution of the short blade 13, and the alternate long and short dash line indicates the long blade 3 of the conventional runner 5 with intermediate blade shown in FIG. The pressure distribution is shown. 3 and 4, the upper line indicates the pressure distribution on the working surface (positive pressure surface) and the lower line indicates the reaction surface, as in FIGS. 3 and 4. The pressure distribution of the (negative pressure surface) is shown, and the result of integrating the pressure difference between the working surface and the reaction surface from the inlet side to the outlet side indicates the blade load at this position (band 11 side).

  As shown in FIG. 7, in the long blade 12 of the present embodiment, the blade length on the band 11 side is extended to the outlet side (the inlet side of the water flow during pump operation) than the conventional long blade, It can be seen that the blade load at the outlet (water flow inlet during pump operation) can be reduced as compared to the conventional long blade. As a result, the pump operation characteristics at a high head can be improved, and the backflow limit at the time of pump operation can be shifted to the small flow rate side to stabilize the operation.

  FIG. 8 is a partially cutaway partial cross-sectional view showing a third embodiment of the hydraulic machine according to the present invention, taking a Francis pump turbine as an example.

  In the runner 14 with intermediate blade according to the present embodiment, the position where the blade thickness Tb of the short blade 13 becomes the maximum blade thickness Tbmax is more than the half L / 2 of the blade length L from the inlet IN to the outlet EX of the short blade 13. It is set on the IN side. The short blade 13 is configured such that the blade thickness Tb smoothly decreases from the position of the maximum blade thickness Tbmax to the inlet IN side and the outlet EX side. Here, the blade thickness Tb can be kept at the maximum blade thickness Tbmax from the position of the maximum blade thickness Tbmax to the inlet IN side.

  The thicknesses of the long blade 12 and the short blade 13 are determined so as to be able to withstand the force received by the blade load determined by the pressure difference between the working surface and the reaction surface, but the blade load acting on the short blade 13 is long blade 12. In many cases, the blade thickness Tb of the short blade 13 does not need to be the same as the blade thickness of the long blade 12. At this time, by adopting the configuration of this embodiment, the width of the inter-blade channel 26 formed by the long blades 12 and the short blades 13 can be widened on the outlet EX side of the short blades 13. it can.

  In general, it is known that the friction loss due to the flow path is proportional to the square of the flow velocity of water flowing through the flow path. If the width of the inter-blade flow path 26 is widened according to this embodiment, the inter-blade flow path 26 Since the flow rate of water becomes small and the friction loss in the inter-blade channel 26 can be reduced, the efficiency can be improved.

  Thus, in the present embodiment, the position where the blade thickness Tb of the short blade 13 of the runner 14 with the intermediate blade is the maximum blade thickness Tbmax is set to a half L / L of the blade length L from the inlet IN to the outlet EX of the short blade 13. Since it is set on the inlet IN side of 2, the width of the inter-blade channel 26 formed by the long blades 12 and the short blades 13 can be widened, and the friction loss in the inter-blade channel 26 can be reduced. Can do.

  FIG. 9 is a partially cutaway partial cross-sectional view showing a fourth embodiment of the hydraulic machine according to the present invention, taking a Francis pump turbine as an example.

  In the runner 14 with intermediate blade according to the present embodiment, the short blade 13 and the long blade 12 adjacent to the working surface side (pressure surface side) of the short blade 13 overlap in the blade length direction from A to B. In B, the blade thickness Tb of the short blade 13 is made smaller than the blade thickness Ta of the long blade 12. In this case, the blade thickness Tb may be gradually decreased toward the exit EX side of the short blade 13.

  As described above, in the present embodiment, the blade thickness Tb of the short blade 13 is made smaller than the thickness Ta of the long blade 12 in the overlap direction AB between the long blade 12 and the short blade 13 in the blade length direction. Since the width of the path 26 is increased, the friction loss in the inter-blade channel 26 can be reduced. Furthermore, the workability at the time of manufacture and maintenance inspection of the runner 14 with intermediate blades is improved by expanding the inter-blade channel 26.

  In the third embodiment and the fourth embodiment, the blade thickness Tb of the short blade 13 is configured to gradually decrease from the position where the blade thickness Tbmax reaches the maximum blade thickness Tbmax to the outlet EX of the short blade 13. The blade thickness Tb is preferably as follows.

  FIG. 10 is a diagram showing the blade surface pressure distribution on the central streamline during the water turbine operation of the runner 14 with intermediate blades in the third or fourth embodiment of the hydraulic machine according to the present invention. FIG. 11 is a partially cutaway partial sectional view used for explaining the blade thicknesses of the long blade 12 and the short blade 13 on the central stream line of the runner 14 with intermediate blades.

  As shown in FIGS. 10 and 11, the pressure difference ΔPa between the action surface (positive pressure surface) and the reaction surface (negative pressure surface) at a position away from the inlet IN side of the long blade 12 by the distance L, Similarly, when comparing the same pressure difference ΔPb at a position away from the inlet IN by the distance L, it can be seen that the pressure difference ΔPb of the short blade 13 is smaller than the pressure difference ΔPa of the long blade 12 at any position. That is, since the force acting on the short blade 13 at each position is smaller than the force acting on the long blade 12 at the same position, the blade of the short blade 13 is based on the pressure difference ΔPa, ΔPb and the blade thickness Ta of the long blade 12. There is a relationship with the thickness Tb. That is, in this case, the blade thickness Tb of the short blade 13 may satisfy the following formula, for example.

[Equation 1]
Tb ≧ α × (ΔPb / ΔPa) × Ta (1)
Here, α is a coefficient determined from a strength surface such as a drop or stress.

  In this way, the blade thickness Tb of the short blade 13 becomes a shape that gradually decreases from the position where the maximum blade thickness Tbmax is reached to the outlet EX of the short blade 13 based on the blade load ΔPb.

  Here, if the blade thickness Tb is positively determined using the equation (1), the values for the long blade 12 and the short blade 13 having a certain shape are used for the pressure differences ΔPa and ΔPb. If the blade thickness Tb is corrected from the shape of the short blade 13 using equation (1), a better shape of the short blade 13 can be obtained. When the blade thickness Tb is to be positively determined in this way, the pressure differences ΔPb and ΔPa change somewhat by correcting the blade thickness Tb, but the pressure differences ΔPa and ΔPb are obtained by numerical simulation using an electronic computer. The optimum blade shape can be obtained by determining the blade thickness Tb by repeatedly calculating the pressure difference ΔPa, ΔPb by using the blade thickness Tb obtained from this and calculating the pressure difference ΔPa, ΔPb again.

  As described above, the hydraulic machine according to the present invention can reduce the difference in blade load between the long blade and the short blade by increasing the blade width between the long blade and the short blade of the runner with intermediate blade. It is possible to suppress turbulence at the turbine inlet of the short blade and flow separation, while maintaining the stable operation by shifting the back flow limit to the small flow rate side during the pump high head operation of the long blade.

  Further, the hydraulic machine according to the present invention can further improve the hydraulic efficiency by widening the flow path width between the long blade and the short blade of the runner with intermediate blades, and further improve the production and maintenance inspections. Workability can be facilitated.

DESCRIPTION OF SYMBOLS 1 Runner 2 Runner vane 3 Long blade 4 Short blade 5 Runner with intermediate blade 6 Crown 7 Band 8a, 8b Outlet edge 9 Rotating shaft 10 Crown 11 Band 12 Long blade 13 Short blade 14 Runner with intermediate blade 15 Outlet edge 16, 17 Intersection 18 Rotating shaft 19 Short blade low-side imaginary line 20 Long blade low-side imaginary line 21 Exit edge 22, 23 Intersection 24 Long blade top-side virtual line 25 Short blade top-side virtual line 26 Channels 27, 27a, 27b Working surface 28 , 28a, 28b Reaction surface 29 Entrance

Claims (2)

In a hydraulic machine including a runner with intermediate blades in which long blades and short blades are alternately arranged along the circumferential direction, the position where the blade thickness of the short blade is maximum is determined from the inlet to the outlet of the short blade. A hydraulic machine, characterized in that it is set on the inlet side with respect to half of the blade length. In a hydraulic machine including a runner with intermediate wings in which long wings and short wings are alternately arranged along a circumferential direction, the blade thickness of the short wings is set to a length adjacent to the working surface side of the short wings and the short wings. A hydraulic machine characterized in that it is formed smaller than the blade thickness of the long blade between the blades.

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