JP2008121574A - Runner for hydraulic machine and method for manufacturing runner for hydraulic machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a runner useful in application to a Francis turbine runner which has a relatively large number of blades and capable of improving manufacturing performance and hydraulic power performance. <P>SOLUTION: This runner 3 provided in a hydraulic machine comprises an outlet side blade part 7b composing a blade part at an runner outlet side and an inlet side blade part 7a having a length of 60%-80% of the whole blade length and composing the blade part at the runner inlet side, and is provided with a plurality of long blades 7 arranged at predetermined intervals along a runner rotation direction (m), and a plurality of short blades 8 arranged alternately with the long blades along a runner rotation direction (m), and formed in the same blade length as the inlet side blade part 7b of the long blade 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a runner for a hydraulic machine used as a component such as a water turbine and a method for producing a runner for a hydraulic machine.

  In general, a so-called Francis type turbine as shown in FIG. 9 is used as the hydraulic machine 1 used in the hydroelectric power generation facility. The Francis type turbine is mainly composed of a spiral casing 2, a speed ring 10, a stay vane 12, a guide vane 9, a runner 3, a main shaft 16, and a suction pipe (draft tube) 14. The runner 3 of the hydraulic machine 1 is connected to a generator (not shown) via the main shaft 16, while water from the upper pond (not shown) is guided to the spiral casing 2, and the spiral casing 2 Angular motion is imparted while increasing the speed in the process of passing through the inner peripheral speed ring 10, stay vane 12 and guide vane 9, and the runner 3 is rotated. The rotational motion of the runner 3 rotates the generator via the main shaft to generate electricity. On the other hand, the water that has rotated the runner 3 flows out from the outlet side (inner peripheral side) and flows to the downstream lower pond (not shown) through the suction pipe 14.

  Here, the runner used in the hydraulic machine is the most important component for transferring energy between the fluid and the hydraulic machine as described above, and its performance greatly affects the performance of the entire hydraulic machine. Therefore, developing a high-performance runner is an important item in the design of hydraulic machines, and various performance improvement measures have been proposed for the runner.

  In recent years, as one of the performance improvement measures, a so-called splitter runner in which short blades and long blades having different blade lengths are alternately arranged along the runner rotation direction has been put into practical use. Here, a difference in characteristics between a normal runner having a uniform blade length and a splitter runner will be described with reference to FIGS. FIG. 10 is a cross-sectional view taken along the meridian plane of each wing with the normal runner 51 and the splitter runner 52 overlapped. 11 is a cross-sectional view of the arrangement of the blades 54 of the ordinary runner 51 as a curved surface obtained by rotating one streamline on the meridian surface of the blades around the main axis. FIG. 12 shows the long blades of the splitter runner 52. 6 is a cross-sectional view of the arrangement of 61 and short blades 62 as viewed from a curved surface obtained by rotating one streamline on the meridian surface of the blades around the main axis. FIG.

  As shown in FIGS. 10 to 12, the splitter runner 52 has a larger number of blades than the ordinary runner 51, while the runner outlet side is composed of only the long blades 61. It has been confirmed that the gap h is not excessively small, the advantages of the multi-blade runner can be maximized, and excellent hydraulic performance is exhibited.

  That is, although the splitter runner 52 is a multi-blade runner, the number of blades on the runner outlet side can be substantially reduced, so that the blades (long blades 61) can be extended toward the runner outlet side. Therefore, the splitter runner 52 can reduce the swirling flow that can occur on the runner outlet side, and can also provide a rectifying effect between the long blade flow paths by the short blades, and can suppress a change in the flow rate of the water flow k2. As a result, as shown in FIG. 10, on the runner outlet side, the normal runner 51 is directly affected by the centrifugal force, and the deviation of the water flow k1 toward the runner band 56 occurs. In the splitter runner 52 having long blades and short blades, the deviation of the water flow k2 toward the runner band 56 is eliminated, and the turbine efficiency is improved.

  Furthermore, as shown in FIGS. 11 and 12, the splitter runner 52 has a large number of blades on the runner inlet side and can reduce the blade load per blade on the runner inlet side. It is possible to reduce the circulation (blade load) γ2 around the blades at the end portions on the runner inlet side of the long blades 61 and 62 with respect to the circulation (blade load) γ1 around the blades at the end of the 54 runner inlet side. it can. Therefore, in the splitter runner 52, since the circulation γ2 around the blade is reduced, the deflection force with respect to the fluid based thereon can be reduced. That is, the angle component (inflow angle) δ2 of the fluid inflow velocity vector w obtained from the absolute fluid inflow velocity vector v and the peripheral velocity vector u of the long blade 61 and the short blade 62 rotating in the m direction is increased. Can do. As a result, the angle difference α2 between the inflow angle δ2 and the blade inlet angle β2 can be suppressed to be substantially smaller than the angle difference α1 between the inflow angle δ1 of the normal runner 51 and the blade inlet angle β1. Thereby, in the splitter runner 52, the separation of the flow can be prevented at the end of the long blade 61 and the short blade 62 on the runner inlet side, and the cavitation on the runner inlet side (pressure at a certain point in the hydraulic machine in operation is saturated). It is possible to suppress the occurrence of a boiling phenomenon in which bubbles are generated when the vapor pressure is reduced.

  Further, as a technique related to such a splitter runner, for example, an intermediate blade having a length equal to or less than the length of the main blade is arranged between the main blades having the number of blades of nine or less, thereby improving the efficiency and cavitation characteristics of the pump turbine. There has been proposed an impeller for a pump turbine (see, for example, Patent Document 1). In addition, a Francis-type pump that extends the low-power operation range while suppressing the occurrence of cavitation by shifting the short blade to the suction surface side of the long blade from the intermediate position along the runner rotation direction between the long blades A water turbine runner is also known (see, for example, Patent Document 2).

Furthermore, after the long blade and the crown are integrally cast, the production procedure of welding the short blade and the band in sequence is adopted to improve the finish accuracy of the runner channel surface in the splitter runner and the assembly workability. A manufacturing method has also been proposed (see, for example, Patent Document 3).
JP 2000-54944 A JP 2001-329937 A JP2001-304088

  By the way, a runner used for a Francis type turbine is generally composed of 13 to 17 blades of main wings (long blades), and is composed of 26 to 34 blades when short blades are arranged between the main wings. Will be. In this case, the splitter runner is manufactured by using integral casting as described in Reference 3 above, and long blades, short blades, crowns and bands are individually manufactured, and the long blades and short blades are welded to the crowns and bands. The manufacturing method to do is taken. When using the former integral casting, shaping of the blade shape by grinding is required. On the other hand, in the case of the latter welding assembly, difficult operations such as welding work and grinding shaping of the welded part are required. Is done.

  Therefore, the difficulty of manufacturing such a splitter runner is a factor that hinders the application of the splitter runner itself and the application of the optimum design to the splitter runner. Here, the techniques of the above-mentioned documents 1 and 2 are mainly for improving the performance of a pump turbine runner with a small number of blades, and the hydraulic performance and manufacturability of a Francis turbine runner with a large number of blades. There is not much consideration for increasing the value.

  Therefore, the present invention has been made to solve such a problem, and is useful when applied to, for example, a Francis type turbine runner having a relatively large number of blades, and also improves manufacturability and hydraulic performance. It is an object of the present invention to provide a hydraulic machine runner capable of producing a hydraulic machine and a method for producing a hydraulic machine runner.

  In order to achieve the above-mentioned object, the runner of the hydraulic machine according to the present invention has an outlet side blade portion constituting a blade portion on the runner outlet side and a length of 60% or more and 80% or less of the entire blade length. And a plurality of long blades arranged at predetermined intervals along the runner rotation direction and alternately arranged with the long blades along the runner rotation direction. And a plurality of short blades formed with the same blade length as the inlet-side blade portion of the long blade.

  INDUSTRIAL APPLICABILITY The present invention is useful when applied to, for example, a Francis type turbine runner having a relatively large number of blades, and is capable of improving manufacturability and hydraulic performance, and a hydraulic machine runner manufacturing method. Can be provided.

The best mode for carrying out the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a cross-sectional view of a long blade 7 and a short blade 8 of a runner 3 provided in a hydraulic machine as viewed from a curved surface obtained by rotating one streamline on the meridian surface of the blade around a main axis. In FIG. 1, only two pitches of the long blades 7 and the short blades 8 are shown in order to avoid complication of the drawing.

  As shown in FIG. 1, the runner 3 includes a plurality of long blades 7 having a long blade length (camber line length) and a plurality of short blades (also referred to as intermediate blades) 8 having a blade length shorter than the long blade 7. Are splitter runners arranged alternately along the rotation direction of the main shaft 16, that is, along the runner rotation direction m. In the runner 3, the long blades 7 and the short blades 8 are disposed in the runner main body, for example, 13 to 17, respectively, and the total number of blades is 26 to 34. That is, the runner 3 is configured as a multi-blade runner suitable as a Francis type turbine runner.

  Next, the characteristic structure of the runner 3 having the long blades 7 and the short blades 8 as runner vanes will be described based on FIGS. 2A to 2C in addition to FIG. Here, FIGS. 2A to 2C are views for explaining the structure of the runner 3 and the manufacturing method thereof, and FIG. 2A is the inlet side blade portion 7a of the long blade 7 with respect to the runner crown 5 and the runner band 6. And it is a figure which shows the state just before the short blade 8 is joined. 2B shows a state immediately after the inlet blade portion 7a and the short blade 8 are joined to the runner crown 5 and the runner band 6 of FIG. 2A and immediately before the outlet blade portion 7b of the long blade 7 is joined. It is a figure which shows a state. Further, FIG. 2C shows that the runner 3 is formed by joining the outlet side blade portion 7b of the long blade 7 to the runner crown 5 and the runner band 6 in which the inlet blade portion 7b and the short blade 8 of FIG. 2B are joined. It is a figure which shows the state made.

  That is, as shown in FIG. 1 and FIGS. 2A to 2C, each long blade 7 of the runner 3 has an inlet side blade portion 7 a constituting a blade portion on the runner inlet side and an outlet side constituting a blade portion on the runner outlet side. It is formed with a two-piece structure including the blade portion 7b. Here, the runner inlet side is the side where water from the upper pond to the lower pond is introduced into the runner 3 during water turbine operation (power generation operation), that is, the spiral casing side (guide vane side). On the other hand, the runner outlet side is the side from which water flowing from the upper pond to the lower pond flows out of the runner 3 during the water turbine operation, that is, the suction pipe side.

  The inlet-side blade portion 7a includes a camber line 7d that connects the end portion 23 on the runner inlet side of the long blade 7 and the end portion 26 on the runner outlet side of the long blade 7 along the direction in which the long blade 7 extends. The length Ln (the total blade length of the long blade 7) is 60% to 80% (60% or more and 80% or less). On the other hand, the outlet blade portion 7b has a blade portion formed by a blade length obtained by subtracting the length of the inlet blade portion 7a from the entire blade length of the long blade 7 and an end portion 25 on the runner inlet side of the blade portion. It is comprised with the welding part 7c joined to the edge part 24 by the side of the runner exit of the side blade | wing part 7a. The short blade 8 is formed of the same member as the end 23 on the runner inlet side of the long blade 7. Therefore, the end 8a on the runner inlet side of the short blade 8 having the same blade shape (and the same size) as the inlet blade portion 7a and the end portion 8b on the runner outlet side of the short blade 8 are connected to the short blade. The length Ls of the camber line 8f connected along the direction in which the blade 8 extends is the same length as the inlet blade portion 7a, that is, 60% to 80% of the total blade length Ln of the long blade 7. It is configured. Further, the inlet blade portion 7a and the short blade 8 formed in the same blade shape have a constant thickness (such as the end portions 23 and 8a on the runner inlet side and the end portions 24 and 8b on the runner outlet side). (Thickness) It is formed at t1.

  Here, the manufacturing method of the runner 3 having such a structure will be schematically described. First, as shown in FIGS. 2A and 2B, the inlet blade portion 7 a of the long blade 7 with respect to the runner crown 5 and the runner band 6. And the short blade 8 are joined together by welding. Next, as shown in FIGS. 2B and 2C, the runner crown 5 and the runner band 6 in which the inlet blade portion 7a and the short blade 8 are joined, respectively, and the inlet blade portion 7a (the end on the runner outlet side). The outlet blade portion 7b is joined to the portion 24) by welding. Thereafter, the runner 3 is manufactured through grinding and shaping of the welded portion.

  In general, the most difficult work in manufacturing a splitter runner is welding work and grinding work on the runner outlet side of the short blade accessed from between the long blades on the runner exit side. In the method of manufacturing the runner 3 according to the present embodiment described above, welding and grinding of the inlet blade portion 7a and the short blade 8 to the runner crown 5 and the runner band 6 are easy before the outlet blade portion 7b is attached. Can be done. That is, since the long blades 7 of the runner 3 are configured in a two-piece structure, it is possible to easily perform welding operations and operations such as narrowing between the blades and grinding and shaping the welded portions. Thereby, although the runner 3 is a multiblade runner for Francis turbines, it is possible to improve the reliability of the welded joint and the finishing accuracy of the blade shape. Further, the inlet blade portion 7a and the short blade 8 are configured with the same blade shape, and almost the entire blade portion is formed with the same thickness, so that it is possible to perform press molding with a plate material that eliminates blade-shaped machining. This can greatly contribute to the reduction of runner manufacturing costs.

  When the runner 3 is manufactured, the runner crown 5, the inlet blade portion 7a, and the short blade 8 are integrally cast, the runner band 6 is welded to the unit, and the outlet blade The runner 3 may be manufactured by welding the portion 7b. Alternatively, after the inlet blade portion 7a and the short blade 8 are joined to the runner crown 5, the short blade 8 is joined, and then the runner band 6 is joined to this unit. May be produced.

  Next, the shape of the long blades 7 and the short blades 8 related to the hydraulic characteristics of the runner 3 and the arrangement relationship thereof will be described based on FIGS. 3 to 6 in addition to FIG. Here, FIG. 3 is a diagram showing a change in blade load of the long blade and the short blade corresponding to a change in the length ratio of the short blade to the long blade, and FIG. 4 is a diagram showing the long blade and the short blade of the runner 3. It is a figure showing the blade surface pressure distribution around the wing | blade of a wing | blade. Further, FIG. 5 is a diagram showing a change in blade load of the long blade and the short blade according to a change in a relative position of the short blade with respect to the long blade, and FIG. 6 is a runner inlet side of the short blade and the long blade. It is a figure showing the cavitation characteristic.

  That is, in FIG. 3 described above, in detail, when the blade length of the short blade 8 is extended to a length 0 to the same length as the entire blade length of the long blade 7 (length ratio 1.00). The change in the blade load of the long blade 7 and the blade load of the short blade 8 is shown by the result of flow analysis such as CFD (Computational Fluid Dynamics). The relative blade load on the vertical axis is expressed as a relative value where the blade load per long blade is 1 when there is no short blade 8 (when the length ratio of the short blade 8 is 0.00). In FIG. 3, when the length of the short blade 7 is 1.00, that is, when the number of blades of the long blade 7 is doubled, the blade load per blade is halved. Further, when the blade length of the short blade 8 is shortened, the blade load of the short blade 8 is reduced more than the blade length is reduced, and the blade length of the short blade 8 is 50% of the long blade 7 (the length of the short blade 8). Below the height ratio 0.50), the short blade 8 hardly shares the blade load and does not function as a blade.

  Here, as shown in FIG. 3, the blade load of the short blade 8 suddenly increases before the length ratio of the short blade 8 exceeds 50% and further reaches 60% (the inclination of the blade load is relatively large). Furthermore, it can be seen that when the length ratio is 60% or more, the increasing rate of the blade load of the short blade 8 is relatively stable (the inclination of the blade load is relatively small). Therefore, in the runner 3 of the present embodiment, as shown in FIG. 1, the gap between the blades on the runner outlet side is secured to some extent to stabilize the water flow, and the blade load of the long blades 7 is reduced. The short blade 8 is configured with a length of 60% or more and 80% or less of the total blade length of the long blade 7 so that the blade 8 can be efficiently shared. Further, in the runner 3 of the present embodiment, in order to improve productivity, the inlet-side blade portion 7a of the long blade 7 that uses the blade shape of the short blade 8 is also 60 of the total blade length of the long blade 7. % To a length of 80% or less.

  FIG. 4 described above shows a case where, for example, the short blade 8 having a length of 70% of the total blade length of the long blade 7 is arranged at the center position of the pitch along the runner rotation direction between the adjacent long blades 7. The blade surface pressure distribution according to the distance from the runner inlet end side along the blade surfaces of the long blade 7 and the short blade 8 is obtained by three-dimensional flow analysis (CFD). Here, the solid line indicates the long blade 7 and the broken line indicates the short blade 8, and the upper side of the solid line and the broken line indicates the pressure on the pressure surface side (pressure surface side) of the long blade 7 and the short blade 8, The lower side of the solid line and the broken line indicates the pressure on the suction surface side of the long blade 7 and the short blade 8. In FIG. 4, the difference between the pressure on the pressure surface side and the pressure on the suction surface side of the same blade is the work of the blade, that is, the blade load per blade. From the result of FIG. 4, the short blade 8 is configured with 70% of the total blade length of the long blade 7, and the short blade 8 effectively shares the blade load of the long blade 7 particularly on the runner inlet side. You can see that

  FIG. 5 shows that the short blade 8 is 70% of the total blade length of the long blade 7, for example, and the long blade 7 when the arrangement relationship of the short blade 8 with respect to the long blade 7 in the runner rotation direction is changed. The change of the blade load of the short blade 8 is shown by the result of flow analysis (CFD). Here, in FIG. 5, as shown in FIG. 1, the end portion 8 b on the runner outlet side of the short blade 8 and the inlet blade portion (of the long blade 7) adjacent to the pressure surface 8 c side of the short blade 8. 7a, the pitch along the runner rotation direction between the runner outlet side end 24 and the runner exit side end direction 24 (the direction in which a rotation locus D2 extends later) is λ1, and the end 8b of the short blade 8 on the runner exit side A pitch along the runner rotation direction (D2 direction) between the short blade 8 adjacent to the suction surface 8d side of the short blade 8 (of the long blade 7) and the end portion 24 on the runner outlet side is defined as λ2. ing.

  That is, FIG. 5 shows (λ2−λ1) / (λ1 + λ2) corresponding to the ratio of λ1 and λ2 when the above pitches are defined as λ1 and λ2, that is, (the inlet blade portion of the long blade 7). The long blade when the separation distance (mounting posture in the inclined direction of the short blade 8) between the suction surface 22 side of the end portion 24a of the 7a and the pressure surface 8c side of the (end portion 8b) of the short blade 8 is changed. 7 shows changes in blade loads of the blades 7 and 8. In FIG. 1, reference numerals D1, D2, and D3 denote long blades 7 (inlet side blade portion 7a and outlet side blade portion 7b) and end portions 23 and end portions of short blades 8 that rotate along runner rotation direction m, respectively. The rotation locus of the part 8a, the rotation locus of the end portion 24 and the end portion 8b, and the rotation locus of the end portion 26 are shown. Further, in FIG. 1, reference numeral 8 e indicates that the end 8 b of the short blade 8 is disposed so as to be close to the suction surface 22 side of the long blade 7 (that is, the posture in which the short blade 8 is laid down rather than the long blade 7). In order to clearly show that, the outlet blade portion 7b of the long blade 7 is virtually joined to the end portion 8b of the short blade 8 on the runner outlet side.

  As can be seen from FIG. 5, the blade load of the short blade 8 is changed by shifting the position of the end 8 b on the runner outlet side of the short blade 8 toward the suction surface 22 side of the long blade 7 (inlet blade portion 7 a). When the relative pitch relationship is 5% to 10% and the blade load of the short blade 8 shows the maximum value, and the pitch relationship exceeds 15%, the adjacent long blades 7 (end portions 24) are adjacent to each other. It can be seen that the blade load of the short blade 8 is smaller than when the short blade 8 (the end portion 8b) is arranged at the center position of the pitch (0% position). This is because, on the blade surface of the long blade 7, the flow velocity is generally faster on the suction surface 22 side than on the pressure surface 21 side, and the short blade is placed on the suction surface 22 side of the long blade 7 to the extent that it does not extremely impede the flow of water. It is considered that the blade load of the long blade 7 can be effectively shared by the short blade 8 by bringing 8 slightly closer.

  Therefore, in the runner 3 of the present embodiment, the short blades 7 and the short blades 8 are respectively arranged so as to satisfy the following formula 1.

  5 [%] ≦ (λ2−λ1) × 100 / (λ1 + λ2) ≦ 15 [%] Formula 1

  Further, FIG. 6 described above is a runner 3 in which short blades 8 having a length of 70% of the total blade length of the long blades 7 are arranged at the center position of the pitch along the runner rotation direction between the adjacent long blades 7. The cavitation generation limit line on the runner inlet side of the long blade 7 and the short blade 8 is shown on the turbine performance curve with the effective head H of the turbine on the horizontal axis and the flow rate Q on the vertical axis. Specifically, the generation limit line on the pressure surface 21 side of the long blade 7 is shown as Cn1, the generation limit line on the suction surface side of the long blade 7 is shown as Cn2, and the generation limit line on the pressure surface 8c side of the short blade 8 is shown. Is shown as Cs1, and the generation limit line on the suction surface 8d side of the short blade 8 is shown as Cs2.

  Here, since the blade load of the short blade 8 is smaller than the blade load of the long blade 7 and the circulation around the blade is small, the inlet cavitation generation limit lines Cs1 and Cs2 of the short blade 8 are It is shifted to the high head side compared to the generation limit lines Cn1 and Cn2. At this time, as shown in FIG. 1, the inlet angle of the short blade 8 (the angle formed by the line segment extending the camber line 8f to the outer periphery of the arc D1 and the tangent line of the arc D1) βs is the inlet angle of the long blade 7 ( If the camber line 7d is smaller than the angle β) formed by the line extending from the outer circumference of the arc D1 and the tangent to the arc D1, a deflection force based on the circulation around the blade 8 at the end 8a of the short blade 8 is generated. The blade load at the end 8a of the short blade 8 increases on the inlet side. As a result, as shown by the white arrow in FIG. 6, the inlet cavitation generation limit lines Cs1 and Cs2 of the short blade 8 can be moved to the low head side.

  Here, as shown in FIG. 6, the actual operation range of the turbine characteristics is as follows. The end Hmin of the inlet cavitation generation limit line Cs1 on the low head side, the end Hmax of the inlet cavitation generation limit line Cs2 on the low head side, 6 is a usable operating range, and generally, the range from the vicinity of the head of the highest efficiency point to the side of the lower head is mainly used. For this reason, the movement of the short wing 8 at the inlet cavitation generation limit lines Cs1 and Cs2 to the low head side leads to the expansion of the water turbine operation range.

  Therefore, as shown in FIG. 1, in the runner 3 of the present embodiment, the relationship between the pitches of λ1 and λ2 shown in FIG. 5 exceeds 5 ° while ensuring that the relationship between the pitches is 5% or more and 15% or less. In addition, the inlet angle βS of the short blade 8 is configured to be smaller than the inlet angle βn of the long blade 7 by an angle in the range of 5 ° or less (configured to satisfy 0 ° <βn−βs ≦ 5 °). is doing. In other words, with reference to the center position of the pitch along the runner rotation direction between adjacent long blades 7, the end portion 8 a of the short blade 8 is brought slightly closer to the pressure surface 21 side of the long blade 7 and the short blade 8 The short blades 8 are respectively arranged in a posture in which the end portion 8b is slightly close to the suction surface 22 side of the long blades 7.

  Thereby, in the runner 3 of this embodiment, since the limit line of cavitation at the inlet of the short blade 8 can be moved to the low head side, the operation range of the water turbine that is performed while suppressing the occurrence of cavitation is substantially expanded. can do.

  As described above, according to the runner 3 of the hydraulic machine according to the present embodiment, it is useful to effectively bring out the hydraulic performance as the splitter runner of the Francis type turbine runner, and the productivity of the runner body is improved. Can be made.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. Here, FIG. 7 is a cross-sectional view of the long wing 37 and the short wing 38 of the runner 33 according to the present embodiment as seen from a curved surface obtained by rotating one streamline on the meridian surface of the wing around the main axis. FIG. 8 is a diagram illustrating a change in blade load of each blade portion according to a change in the attachment position of the outlet blade portion 37b of the long blade 37 provided in the runner 33 of FIG. In FIG. 7, the same components as those provided in the runner 3 of the first embodiment shown in FIG.

  As shown in FIG. 7, the runner 33 of this embodiment includes long blades 37 and short blades 38 instead of the long blades 7 and short blades 8 included in the runner 3 of the first embodiment. The The long blade 37 includes an outlet-side blade portion 37b instead of the outlet-side blade portion 7b included in the long blade 7 shown in FIG. Further, the short blade 38 is formed in the same blade shape (and the same size) as the inlet blade portion 7a, but the relative arrangement relationship with the long blade is the short blade shown in FIG. Different from 8. That is, as shown in FIG. 7, the runner 33 includes at least end portions 24, 38 b on the runner outlet side of the inlet blade portions 7 a and the short blades 38 of the long blades 37 that are alternately arranged along the runner rotation direction m. The gaps are configured to have the same pitch λ3 along the runner rotation direction m (the direction in which the rotation locus D1 extends).

  Moreover, although the exit side blade | wing part 37b of the long blade 37 is formed in the same shape as the exit side blade | wing part 7b shown in FIG. 1, it is arrange | positioned in the position spaced apart from the inlet side blade | wing part 7a. That is, in the long blade 37, the pressure surface (positive pressure surface) 39 side of the end portion 35 on the runner inlet side of the outlet blade portion 37b is placed on the negative pressure surface 22 side of the end portion 24 on the runner outlet side of the inlet blade portion 7a. In the state where they are close to each other, the inlet side blade portion 7a and the outlet side blade portion 37b are respectively arranged. More specifically, the runner 33 is located between the end 24 on the runner outlet side of each inlet blade portion 7a and the end portion 35 on the runner inlet side of the pair of outlet blade portions 37b. The pitches λ4 along the runner rotation direction m are each λ3 / 2 (λ3 / 2).

  Further, the short blade 38 and the inlet blade portion 7a are 60% or more of the total blade length of the inlet blade portion 7a and the outlet blade portion 37b (total blade length of the long blade 37), The length is 80% or less.

  Here, in FIG. 8 described above, the inlet side blade portion 7a and the short blade 8 having a length of 70% of the total blade length of the long blade 37 are arranged (the outlet blade portion 37b is 30% of the total blade length of the long blade 37). % Of each of the blades of the inlet blade portion 7a, the short blade 38 and the outlet blade portion 37b when λ3 is one pitch and λ4 is varied from 0 to 1 pitch. The change of the total blade load, which is the load and the total of these blade loads, is shown as a result of flow analysis (CFD). The blade loads of the inlet blade portion 7a, the short blade 38, and the outlet blade portion 37b are shown as relative values with respect to the total blade load of these blade portions.

  That is, as shown in FIG. 8, from the state where the camber lines of the inlet side blade portion 7a and the outlet side blade portion 37b are connected to each other (the state where λ4 is less than λ3 / 2), the outlet side blade portion 37b. Is moved to the negative pressure surface 22 side of the end 24 of the inlet blade portion 7a (as λ4 approaches λ3 / 2), the blade of the inlet blade portion 7a is moved. It can be seen that the blade load of the short blade 38 increases as the load decreases. Furthermore, the pressure surface 39 side of the short portion 35 of the outlet side blade portion 37b moves away from the suction surface 22 side of the end portion 24 of the inlet side blade portion 7a (when λ4 exceeds λ3 / 2, that is, FIG. 8). When the inner pitch exceeds 0.5), the blade load of the short blade 38 becomes larger than that of the inlet blade portion 7a. From this result, it can be considered that the relation of the function as the runner vane between the inlet side blade portion 7a and the short blade 38 is substantially replaced.

  Moreover, since the speed of the water flow on the negative pressure surface 22 side of the inlet side blade portion 7a is faster than the pressure surface 21 side, the short portion 35 of the outlet side blade portion 37b is close to the pressure surface 21 side of the inlet side blade portion 7a. The blade load on the outlet side blade portion 37b tends to be slightly larger when closer to the suction surface 22 side.

  Therefore, in the runner 33 of the present embodiment, the inlet blade portion 7a and the outlet blade portion 37b of the long blade 37 and the short blade 38 are arranged so that the pitch λ4 is λ3 / 2, respectively. The blade loads of the side blade portions 7a and the short blades 38 can be made substantially equal, thereby suppressing the occurrence of inlet cavitation that can occur due to the imbalance between the blade loads of the long blades 37 and the short blades 38. .

  As described above, according to the runner 33 according to the present embodiment, it is possible to arrange the blades of the same shape, that is, the inlet blade portion 7a of the long blade 37 and the short blade 38 at an equal pitch, thereby improving the productivity of the runner 33 main body. In addition, the hydraulic performance of the splitter runner can be improved.

  The present invention has been specifically described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the inlet-side blade portion 7a and the short blade 8 of the long blade 7 are formed with the same thickness except for both ends, but are formed with different thicknesses (blade thickness). It may be. In the embodiment described above, the wing shape of the entire long blades 7 and 37 including the outlet side blade portions 7b and 37b has not been particularly described. The long wing and the short wing may be configured to have the same wing shape by changing only the length (from the short wing). Furthermore, in the first embodiment, since the blade member 7a and the short blade 8 are configured by diverting the blade member having the same shape, the above equation 1 and “0 ° <βn−βs ≦ 5 °” are satisfied. However, in the present invention, Equation 1 and “0 ° <βn−βs ≦ 5” are individually obtained by making the inlet blade portion 7a and the short blade 8 into different blade shapes. It is also possible to construct a runner that satisfies the requirements.

Sectional drawing which looked at the curved surface which rotated one streamline of the long blade of the runner with which a hydraulic machine is equipped, and the blade | wing of a short blade around the main axis. The figure which shows the state just before the inlet side blade | wing part and short blade of a long blade are joined with the runner crown and runner band of the runner of FIG. The figure which shows the state just before joining the exit side blade | wing part of a long blade after joining an inlet side blade | wing part and a short blade with respect to the runner crown and runner band of FIG. 2A. The figure which shows the state by which the exit side blade | wing part of the long blade was joined with respect to the runner crown and runner band with which the inlet side blade | wing part and short blade of FIG. 2B were joined, and the runner was formed. The figure showing the change of the blade load of the long blade and the short blade corresponding to the change of the length ratio of the short blade with respect to the long blade of the runner of FIG. The figure showing the blade surface pressure distribution around the long blade of the runner of FIG. 1, and the short blade. The figure showing the change of the blade | wing load of a long wing | blade and a short wing | blade according to the change of the relative position of the short wing | blade with respect to the long wing | blade of the runner of FIG. The figure showing the cavitation characteristic of the runner entrance side of the long wing and short wing of the runner of FIG. Sectional drawing which looked at the curved surface which rotated one streamline of the long blade of the runner which concerns on the 2nd Embodiment of this invention, and the blade | wing of a short blade around the main axis. The figure showing the change of the blade | wing load of each blade | wing part according to the change of the attachment position of the exit side blade | wing part of the long blade with which the runner of FIG. 7 is provided. The longitudinal cross-sectional view which shows the conventional Francis type pump turbine. The figure which overlap | superposed the conventional splitter runner and the normal runner, and looked at the cross section along each meridian surface. Sectional drawing which looked at the arrangement | positioning of the wing | blade of the normal runner of FIG. 10 on the curved surface which rotated the XX line | wire (one streamline in the meridian surface of a wing | blade) of FIG. Sectional drawing which looked at the arrangement | positioning of the long blade and short blade of the splitter runner of FIG. 10 on the curved surface which rotated the XX line | wire (one streamline in the meridian surface of a wing | blade) of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Hydraulic machine, 2 ... Spiral casing, 3,33 ... Runner, 5 ... Runner crown, 6 ... Runner band, 7, 37 ... Long blade, 7a ... Inlet side blade part, 7b, 37b ... Outlet side blade part, 7c ... welded part, 8, 38 ... short blade, 21, 8c, 39 ... pressure surface (positive pressure surface), 22, 8d ... negative pressure surface.

Claims (9)

It consists of an outlet side blade part constituting the blade part on the runner outlet side and an inlet side blade part constituting the blade part on the runner inlet side with a length of 60% or more and 80% or less of the total blade length. A plurality of long wings arranged at predetermined intervals along the
A plurality of short blades alternately arranged with the long blades along the runner rotation direction, and formed with the same blade length as the inlet blade portion of the long blades;
A hydraulic machine runner characterized by comprising:   The runner of a hydraulic machine according to claim 1, wherein the inlet blade portion and the short blade are formed in the same shape.   3. The hydraulic power according to claim 1, wherein the inlet side blade portion and the short blade are formed with a constant thickness except for the end portions on the runner inlet side and the runner outlet side. 4. Machine runner. The pitch along the runner rotation direction between the end on the runner outlet side of the short blade and the end on the runner outlet side of the inlet blade adjacent to the pressure surface side of the short blade is λ1, and the short blade When the pitch along the runner rotation direction between the end on the runner exit side of the runner and the end on the runner exit side of the inlet blade adjacent to the suction surface side of the short blade is λ2,
5 [%] ≦ (λ2−λ1) × 100 / (λ1 + λ2) ≦ 15 [%]
The hydraulic machine runner according to any one of claims 1 to 3, wherein:   The inlet angle of the short blade is configured to be smaller than the inlet angle of the long blade by an angle in the range of more than 0 ° and not more than 5 °. A hydraulic machine runner according to claim 1.   The hydraulic machine runner according to any one of claims 1 to 5, wherein the inlet-side blade portion and the outlet-side blade portion are joined to each other by welding.   The inlet-side blade portion and the outlet-side blade portion are arranged in a state of being separated from each other, and on the suction surface side of the inlet-side blade portion on the runner outlet-side end side, the runner inlet side of the outlet-side blade portion The hydraulic machine runner according to any one of claims 1 to 3, wherein the pressure surface side of the end portion of the hydraulic machine is close.   Between the inlet-side blade portions and the short blades of the long blades arranged alternately along the runner rotation direction, between the end portions on the runner outlet side are equal pitches λ3 along the runner rotation direction, respectively. And the runner outlet side ends of the respective inlet side blade portions and the runner inlet side ends of the pair of outlet side blade portions respectively along the runner rotation direction. The runner of a hydraulic machine according to claim 7, wherein the pitches are each set to λ3 / 2. A method for producing a hydraulic machine runner for producing the hydraulic machine runner according to any one of claims 1 to 8,
Bonding the inlet blade portion and the short blade to a runner crown and a runner band,
Joining the outlet side blade portion to the runner crown and the runner band to which the inlet side blade portion and the short blade are respectively joined;
The manufacturing method of the runner for hydraulic machines characterized by having.

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