JP2016056787A - Runner for hydraulic machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a runner for hydraulic machinery, which can reduce a hydraulic pulsation while suppressing the reduction of efficiency effectively.SOLUTION: A runner 41 according to an embodiment comprises: a runner body 4M to be rotationally driven on a rotation axis O by the water flow into from the outer peripheral side at a hydraulic turbine operation time; and a cylindrical extension member 10 disposed coaxially with the rotation axis O on the rotation axis side of the runner body 4M and extending toward the downstream side of the runner body 4M. The extension member 10 is formed with a plurality of through holes 11 for causing an inner circumferential side region In and an outer circumferential side region Ex to communicate.SELECTED DRAWING: Figure 2

Description

  Embodiments of the present invention relate to a runner of a hydraulic machine.

  In a typical Francis turbine as a hydraulic machine, water flows from the casing to the runner through the stay vane and the guide vane during the operation of the turbine, and the runner is rotationally driven by the water flow, and the generator is rotationally driven through the main shaft. . Thereby, power generation is performed. In addition, the water which rotationally driven the runner flows out to the water discharge channel through the suction pipe.

  In such a Francis turbine, the runner has a crown, a band, and a plurality of blades provided between the crown and the band. The vanes in the runner are designed with an angle and a shape so as to efficiently convert water flow energy into runner rotational energy at the design point, and are fixed between the crown and the band. Basically, at the design point, the outflow direction of the water passing through the runner coincides with the axial direction of the rotation axis of the runner.

  However, because the vanes are fixed in the runner, when the water flow deviates from the design point, the efficiency of converting the water flow energy into the runner rotational energy is lower than the design point efficiency. Sometimes. In this case, a swirl flow may occur downstream of the runner. In particular, during partial load operation at a small flow rate, vortices (foils) are likely to occur in the suction pipe located downstream of the runner due to the swirling flow. The central part (vortex core) of such a vortex has a significantly lower pressure than the surrounding flow, and a cavity filled with air is generated.

  Further, at the time of partial load operation, the vortex core of such a vortex becomes spiral, and the vortex swings around in the suction pipe, in other words, revolves around the center of the suction pipe. In this case, the vortex generates strong water pressure pulsation, and the wall of the suction pipe is struck violently, or other elements that make up the hydroelectric power station are caused to resonate depending on the frequency at which it swings. Sometimes. As a result, vibration and noise in the hydroelectric power plant are generated, and as a result, stable operation may be affected. In particular, in a high specific speed machine with a low head and a large flow rate, vibration and noise due to the vortex as described above tend to be large. Therefore, in the field of Francis turbines, various techniques for reducing hydraulic pulsation have been proposed.

  For example, by providing fins on the inner peripheral surface of the suction pipe to suppress the swirling flow, or by providing an air supply device on the inner peripheral surface of the suction pipe and supplying air from the air supply device toward the vortex, A technique for stabilizing the vortex (suppressing swinging) is known. A technique for supplying air from a main shaft connected to a runner is also known for stabilizing the vortex.

  In the technology of providing fins on the inner peripheral surface of the suction pipe, in order to prevent the wake generated downstream of the fins from colliding with the wall surface on the inner peripheral side of the bent portion of the suction pipe and damaging it, There is also a technique for inclining the fin in one circumferential direction.

  In addition, among the technologies for providing an air supply device on the inner peripheral surface of the suction pipe, as a simple structure, an apparatus for providing an air supply pipe so as to penetrate in the radial direction of the suction pipe, There is also an apparatus in which an annular enclosure having a semicircular cross section is provided on the peripheral surface, and an air supply hole is formed on the center side of the suction pipe of the enclosure.

JP-A-2-140466 Japanese Patent Laid-Open No. 11-153081

  However, the fin and the air supply device provided on the inner peripheral surface of the suction pipe described above have a structure that protrudes toward the center from the inner peripheral surface of the suction pipe. For this reason, when the water flow swirling in the vicinity of the fins or the air supply device passes through the suction pipe, a separation loss of the water flow may occur. Thereby, there exists a problem which efficiency will fall.

  In view of these points, an object of the present invention is to provide a hydraulic machine runner capable of reducing hydraulic pulsation while effectively suppressing a decrease in efficiency.

  The runner of the hydraulic machine according to the embodiment is provided with a runner body that is driven to rotate around a rotation axis by a water flow flowing from the outer periphery side during water turbine operation, and is provided coaxially with the rotation axis on the rotation axis side of the runner body, And a cylindrical extension member extending toward the downstream side of the runner body. The extension member is formed with a plurality of through holes that communicate the inner peripheral side region and the outer peripheral side region.

It is meridional sectional drawing of a Francis turbine provided with the runner by a 1st embodiment. It is meridional sectional drawing of the runner of the Francis turbine of FIG. It is the figure which showed the mode of the vortex which generate | occur | produces in the suction pipe of the Francis turbine of FIG. It is the figure which showed the mode of the vortex which generate | occur | produces in the suction pipe of a common Francis turbine. It is the figure which compared the water pressure pulsation which generate | occur | produces with the Francis turbine of FIG. 1, and the water pressure pulsation which generate | occur | produces with the general Francis turbine of FIG. It is meridional sectional drawing of the runner by 2nd Embodiment. It is the figure which showed the mode of operation | movement of the extension member of the double structure provided in the runner of FIG. It is the figure which showed the pressure of the inner peripheral side area | region of an extension member according to the position of the inner member of the extension member of the runner of FIG. The hydraulic pulsation when air is supplied with the inner member of the extension member of the runner of FIG. 6 covering the through hole of the outer member, and the inner member of the extension member of the runner of FIG. 6 covers the through hole of the outer member. It is the figure which compared the water pressure pulsation at the time of performing air supply in the state which does not exist according to the air supply amount. (A) is a meridional cross-sectional view of a runner according to the third embodiment, and (B) is a diagram showing an operation of a dual structure extension member provided in the runner. It is meridional sectional drawing of the runner by 4th Embodiment. It is meridional sectional drawing of the runner by 5th Embodiment.

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

(First embodiment)
FIG. 1 is a meridional cross-sectional view of a Francis turbine 100 including a runner 41 according to the first embodiment. The Francis turbine 100 includes a spiral casing 1 through which water flows from a water pond through a hydraulic iron pipe (not shown), a plurality of stay vanes 2, a plurality of guide vanes 3, and a runner 41. And. A guide vane 3 is disposed on the outer peripheral side of the runner 41, and a stay vane 2 is disposed on the outer peripheral side of the guide vane 3.

  The runner 41 is coupled to the generator 8 via the main shaft 7. In FIG. 1, a symbol O indicates an axis passing through the rotation center of the main shaft 7. Hereinafter, the axis O may be referred to as the rotation axis of the runner 41, and the direction along the rotation axis O may be referred to as the axial direction of the rotation axis O.

  The stay vane 2 is for guiding the water flowing into the casing 1 during the operation of the water turbine to the guide vane 3 and the runner 41, and is arranged at a predetermined interval in the circumferential direction of the runner 41. A flowing channel is formed. The guide vane 3 is for guiding the water that flows in during the water turbine operation to the runner 41, and is arranged at a predetermined interval in the circumferential direction of the runner 41, and there is a flow path through which water flows between the guide vanes 3. Is formed.

  On the other hand, FIG. 2 is a meridional section view of the runner 41. As shown in FIG. 2, the runner 41 includes a crown 4C coupled to the main shaft 7, a band 4B, a plurality of runner blades 4A provided between the crown 4C and the band 4B, and a radial direction of the crown 4C. It has a runner body 4M composed of a truncated cone-shaped runner cone 4D projecting downstream from the inner end. The runner blades 4A are arranged at a predetermined interval in the circumferential direction, and a flow path through which water flows is formed between the runner blades 4A.

  In such a Francis turbine 100, when the water flows from the guide vane 3 to the runner 41 through the stay vane 2, the runner 41 is driven to rotate around the rotation axis O, and the generator 8 is driven to rotate through the main shaft 7. The Thereby, power generation is performed. The water that rotationally drives the runner 41 flows out to the water discharge channel through the suction pipe 5.

  Each of the plurality of guide vanes 3 is connected to a rotation shaft (not shown) and is rotatable about the rotation shaft. Thereby, the opening degree of the guide vane 3 can be adjusted by rotating around the rotation axis. By changing the opening degree of the guide vane 3, the flow rate flowing into the runner can be adjusted and the power generation amount can be changed.

  Hereinafter, the runner 41 will be described in detail with reference to FIG. In the following description, the inflow side in the flow direction of the water flow that rotationally drives the runner 41 is referred to as the upstream side, and the outflow side is referred to as the downstream side.

  As shown in FIG. 2, the runner 41 of the present embodiment is provided on the rotating shaft side of the runner body 4M coaxially with the rotating shaft O and extends toward the downstream side of the runner body 4M. Is further provided. Specifically, in the present embodiment, the extension member 10 is joined to the tip of the runner cone 4D in the runner body 4M.

  The extension member 10 is cylindrical and extends along the rotation axis O. The distal end portion of the extension member 10 is located downstream of the blade body 4A in the rotation axis O direction and reaches the vicinity of the outlet side end portion of the runner 41 in the rotation axis O direction.

  Further, the extension member 10 is formed with a plurality of through-holes 11 communicating the inner peripheral side region In formed on the inner peripheral side thereof with the outer peripheral side region Ex formed on the outer peripheral side thereof. A plurality of through holes 11 are formed at intervals in the axial direction and the circumferential direction of the extension member 10.

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

  FIG. 3 shows a state in which a spiral vortex W is generated in Francis turbine 100 according to the present embodiment. In general, in this type of Francis turbine, a vortex is likely to be generated due to the swirling flow during partial load operation at a small flow rate, and the vortex core of the vortex tends to be spiral as the flow rate decreases. And the spiral vortex W as shown in FIG. 3 may generate | occur | produce and a strong hydraulic pressure pulsation may generate | occur | produce.

  Such a vortex W is formed so as to extend toward the suction pipe 5 starting from the downstream side of the extension member 10 or its periphery. Then, the vortex W swings around in the suction pipe 5 with a specific period, in other words, revolves around the center of the suction pipe 5, that is, around the rotation axis O. In the suction pipe 5 where such a vortex W is generated, the pressure in the region where the spiral vortex W is closest is relatively smallest, and the pressure in the region where the vortex W is farthest is relatively highest. growing. For this reason, when the vortex W is generated, a periodic water pressure fluctuation based on the specific period occurs inside the suction pipe 5, and as a result, water pressure pulsation may occur.

  In the state where the vortex W sways, the pressure in the region closest to the inner peripheral surface of the suction pipe 5 becomes the smallest in the vortex W around the extension member 10, and the vortex W becomes the suction pipe. The pressure in the region farthest from the inner peripheral surface of 5 is the largest. For this reason, in the region around the extension member 10, there is a region where the pressure increases (“pressure high” in the drawing) or a region where the pressure decreases (“pressure low” in the drawing) depending on the position of the vortex W. It happens. On the other hand, the inner peripheral side region In of the extension member 10 is partitioned from the outer peripheral side region Ex where the pressure fluctuates, and is located on the side close to the starting point of the vortex core of the vortex W.

  Here, by providing the extension member 10, the extension member 10 becomes a resistance against the swirling of the vortex W, and the amplitude of the vortex W is generated as compared with the case of a general Francis turbine as shown in FIG. 4. Is suppressed. Further, in the present embodiment, the through-hole 11 is formed in the extension member 10, so that the through-hole 11 as shown by the arrow in FIG. 3 from the region where the pressure has increased in the region around the extension member 10. Through, the water flows into the extension member 10. Thereby, the pressure in the area | region where the pressure rose among the area | regions around the extension member 10 is balanced with the pressure inside the extension member 10, and it can reduce the pressure in the area | region where the said pressure rose.

  As a result, the pressure difference between the area where the pressure has increased and the area where the pressure has decreased among the areas around the extension member 10 can be reduced, thereby reducing the pressure fluctuation in the vicinity of the vortex core starting point of the vortex W. be able to. Thereby, according to this Embodiment, since the amplitude at the time of the vortex W swinging can be suppressed entirely, a hydraulic pulsation can be reduced.

  FIG. 5 is a diagram comparing hydraulic pulsations generated in the Francis turbine 100 of FIG. 1 and the general Francis turbine of FIG. The horizontal axis in FIG. 5 indicates the output (flow rate), and the vertical axis indicates the water pressure pulsation based on the vibration measured by the sensor installed in the suction pipe. As is apparent from FIG. 5, according to the present embodiment, the extension member 10 having the through-holes 11 is provided, so that during partial load operation, that is, on the left side of the drawing from the “design point” in the figure. It can be seen that the water pressure pulsation at the flow rate is reduced as compared with a general Francis turbine.

  According to the first embodiment described above, the hydraulic pulsation is generated with an extremely simple structure in which the one extension member 10 having the through hole 11 is provided on the rotating shaft side of the runner body 4M of the runner 41. Can be reduced. Such an extension member 10 can be easily provided even if the Francis turbine is large, and is concentrated on the rotating shaft O side of the runner 41, so that the apparatus configuration is not complicated. Further, the extension member 10 is provided apart from the position where the swirling water flow passes in the suction pipe 5, thereby suppressing occurrence of water flow separation loss in the suction pipe 5. Therefore, it is possible to reduce the water pressure pulsation without complicating the apparatus configuration and effectively suppressing the decrease in efficiency.

(Second Embodiment)
Next, a runner 42 according to the second embodiment will be described with reference to FIGS. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals. Hereinafter, differences from the first embodiment will be mainly described.

  FIG. 6 is a meridional cross-sectional view of the runner 42 according to the second embodiment. As shown in FIG. 6, in the runner 42 according to the present embodiment, the extension members 10 are disposed on the inner peripheral side of the cylindrical outer member 20 and the outer member 20 that are provided coaxially with the rotation axis O, respectively. And a cylindrical inner member 30. The inner peripheral side region In is formed on the inner peripheral side of the inner member 30, and the outer peripheral side region Ex is formed on the outer peripheral side of the outer member 20.

  The outer member 20 has a cylindrical shape, is joined to the tip of the runner cone 4D, and extends along the rotation axis O. The distal end portion of the outer member 20 is located downstream of the blade body 4A in the rotation axis O direction and reaches the vicinity of the outlet side end portion of the runner 42 in the rotation axis O direction. The outer member 20 is formed with the same through-hole 11 as in the first embodiment.

  On the other hand, the inner member 30 is also cylindrical and is disposed so as to extend along the rotation axis O. The inner member 30 is formed with a plurality of communication holes 31 penetrating in the radial direction. In FIG. 6, each of the plurality of communication holes 31 overlaps any one of the plurality of through holes 11 formed in the outer member 20 in the radial direction. That is, in the present embodiment, the arrangement pattern of the plurality of communication holes 31 is the same as the arrangement pattern of the plurality of through holes 11. Hereinafter, the state shown in FIG. 6 in which each of the plurality of communication holes 31 overlaps any of the plurality of through holes 11 formed in the outer member 20 in the radial direction is referred to as a “first state”. In the first state, the wall portion of the inner member 30 does not cover the plurality of through holes 11, and the through holes 11 communicate with the inner peripheral region In and the outer peripheral region Ex through the communication holes 31. .

  In the present embodiment, the proximal end of the inner member 30 is inserted into the runner cone 4 </ b> D and is connected to the drive unit 32 disposed on the main shaft 7 side with respect to the proximal end of the inner member 30. The inner member 30 is movable along the rotation axis O by the drive unit 32.

  In the present embodiment, when the inner member 30 is moved along the rotation axis O by the drive unit 32 from the first state illustrated in FIG. 6, each of the plurality of communication holes 31 corresponds to the plurality of through holes 11. It comes off from the state which overlaps with either in radial direction (refer FIG. 7). Hereinafter, the state shown in FIG. 7 in which each of the plurality of communication holes 31 is out of the state of overlapping the plurality of through holes 11 formed in the outer member 20 in the radial direction is referred to as a “second state”. Call it. In the second state, each of the plurality of communication holes 31 is out of the state of overlapping the plurality of through holes 11 in the radial direction, and the wall portion of the inner member 30 covers the plurality of through holes 11. It has become.

  Further, in the present embodiment, a plurality of air flow holes 30A, which will be described in detail later, are formed at intervals in the circumferential direction on the proximal end side of the inner member 30, that is, the main shaft 7 side. The air circulation hole 30A is a part of a configuration for supplying air, and details thereof will be described later. In addition, the main shaft 7 of the present embodiment is cylindrical, and the drive unit 32 described above is accommodated mainly on the inner peripheral side of the main shaft 7.

  Next, the drive unit 32 will be described. As shown in FIG. 6, the drive unit 32 is fixed to the inner peripheral surface of the main shaft 7 and has a disc-shaped guide plate 33 having a through hole 33 </ b> A formed at the center thereof, and a through hole 33 </ b> A of the guide plate 33. A rod portion 34 that is slidably inserted and extends toward the inner member 30 along the axis O, a disc-shaped closing plate 35 fixed to the tip of the rod portion 34, and a closing plate 35 of the rod portions 34. And a disc-shaped biasing member holding plate 36 fixed to an intermediate portion between the guide plate 33 and the guide plate 33 and the biasing member holding plate 36. And an urging member 37.

  A base end of the inner member 30 is fixed to a surface of the closing plate 35 facing the suction pipe 5 side, and is thereby connected to the drive unit 32. Further, the urging member 37 urges the rod portion 34 so that the peripheral portion 4CA of the central opening of the crown 4C is closed by the outer peripheral portion of the surface of the closing plate 35 facing the main shaft 7 side. It has become. In the present embodiment, in the state where the peripheral edge 4CA of the central opening of the crown 4C is closed by the closing plate 35, as shown in FIG. 6, each of the plurality of communication holes 31 is in the “first state”. It has become.

  The inner peripheral side of the main shaft 7 of the present embodiment is open to the atmosphere at the portion on the generator 8 side, and in the drive unit 32, an air circulation hole 33B is formed in the outer peripheral side portion of the guide plate 33. . Therefore, in the state where the peripheral edge 4CA of the central opening of the crown 4C is closed by the closing plate 35, the pressure in the internal space of the opening of the crown 4C is in the atmospheric pressure state. On the other hand, in the state where the peripheral edge 4CA of the central opening of the crown 4C is closed by the closing plate 35, the inner peripheral side region In on the inner peripheral side of the inner member 30 is not in communication with the atmosphere.

  In such a drive unit 32, when the pressure in the inner peripheral region In becomes smaller than a predetermined pressure, that is, a value obtained by subtracting the urging force of the urging member 37 from the atmospheric pressure, the closing plate 35 is caused by atmospheric pressure. The central member of the crown 4C is opened by being pushed toward the suction pipe 5 and the urging member 37 extends. At this time, the inner member 30 moves to the downstream side of the runner body 4M along with the closing plate 35.

  In the present embodiment, with the central opening of the crown 4C opened, as shown by the arrow α in FIG. 7, the inner peripheral side of the main shaft 7, the central opening of the crown 4C, and the air in the inner member 30 Air flows into the inner circumferential side region In of the inner member 30 through the circulation hole 30A. That is, the inner peripheral side of the main shaft 7, the central opening of the crown 4C, and the air circulation hole 30A of the inner member 30 constitute an air supply path during supply. As described above, the runner 42 according to the present embodiment sucks out through the inner peripheral side of the main shaft 7 and the inner peripheral side region In of the inner member 30 when the pressure in the inner peripheral region In becomes smaller than a predetermined pressure. Air supply (natural air supply) is performed toward the downstream side of the pipe 5, that is, the runner body 4M.

  Note that the air supplied toward the downstream side of the runner body 4M through the inner peripheral region In on the inner peripheral side of the inner member 30 flows along the rotation axis O. When air is supplied in this way, as shown in FIG. 7, each of the plurality of communication holes 31 is in the “second state”.

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

  In the present embodiment, when the pressure in the inner peripheral region In is equal to or higher than the predetermined pressure described above, that is, the value obtained by subtracting the biasing force of the biasing member 37 from the atmospheric pressure, as shown in FIG. The closing plate 35 in the drive unit 32 closes the peripheral edge 4CA of the opening at the center of the crown 4C. Therefore, in the extension member 10, each of the plurality of communication holes 31 of the inner member 30 overlaps with one of the plurality of through holes 11 formed in the outer member 20 in the radial direction (first state). Further, air supply through the inner peripheral side of the main shaft 7 and the inner peripheral side region In of the inner member 30 is not performed.

  In this state, when a spiral vortex is generated in the suction pipe 5, a region where the pressure increases and a region where the pressure decreases are generated around the extension member 10 or inside the suction tube 5, and water pressure pulsation occurs. Furthermore, the through-hole 11 of the extension member 10 communicates the inner peripheral side region In and the outer peripheral side region Ex, so that the extension member 10 passes through the through-hole 11 from the region around the extension member 10 where the pressure has increased. Water can be allowed to flow into the interior. Thereby, water pressure pulsation can be reduced by reducing the pressure in the region where the pressure has increased.

  On the other hand, when the pressure in the inner peripheral region In is smaller than the predetermined pressure described above, that is, a value obtained by subtracting the biasing force of the biasing member 37 from the atmospheric pressure, the drive unit 32 as shown in FIG. Further, the closing plate 35 is pushed toward the suction pipe 5 by the atmospheric pressure, and the biasing member 37 is extended, so that the central opening of the crown 4C is opened. Thereby, air supply through the inner peripheral side of the main shaft 7 and the inner peripheral side region In of the inner member 30 is performed.

  In this state, a spiral vortex is generated in the suction pipe 5, a region where the pressure increases around the extension member 10 or inside the suction tube 5, and a region where the pressure decreases occurs, resulting in water pressure pulsation. In this case, by supplying air to the low-pressure vortex core of the vortex, the pressure of the vortex core can be increased to stabilize the vortex. Thereby, water pressure pulsation can be reduced. At this time, in the extension member 10, the second state in which each of the plurality of communication holes 31 of the inner member 30 deviates from the state of overlapping with any of the plurality of through holes 11 formed in the outer member 20 in the radial direction. become. Thereby, the reduction effect of the water pressure pulsation by supply air can be heightened.

  This will be described in detail with reference to FIGS. FIG. 8 is a diagram illustrating the pressure in the inner peripheral surface side region In of the extension member 10 according to the position of the inner member 30. Specifically, FIG. 8 shows the pressure (hereinafter referred to as supply air pressure) in the inner peripheral surface side region In in the first state (with holes in the drawing) and the inner peripheral surface in the second state (without holes in the drawing). It is the figure which compared the pressure (henceforth, air supply pressure) of the side area | region In.

  In FIG. 8, the horizontal axis indicates the output (flow rate), and the vertical axis indicates the supply air pressure. In FIG. 8, this means that the air supply is effective when the supply air pressure is above the horizontal axis in the drawing, that is, air can be drawn into the inner member 30 from the main shaft 7.

  As shown in FIG. 8, the supply air pressure of the inner peripheral surface side region In of the inner member 30 in the second state is the supply air pressure of the inner peripheral surface side region In of the inner member 30 in the first state in the entire operation range. Higher than. This is because, in the first state, the pressure in the inner peripheral region In increases due to the influence of the pressure in the outer peripheral region Ex compared to the second state, and the supply air pressure that tries to draw air is increased. It is because it falls. For this reason, when air is supplied in the first state, the amount of air that can be supplied is smaller than when air is supplied in the second state, and the effect of reducing water pressure pulsation due to air supply is reduced. . Further, as shown in FIG. 8, the range in which the air supply in the second state is effective is wider than the range in which the air supply in the first state is effective. Also in this case, when the air supply is performed in the first state, the operating range in which the effect of reducing the water pressure pulsation is narrower than when the air supply is performed in the second state, and the effect of reducing the water pressure pulsation due to the air supply is reduced. Means lower. Therefore, when air supply is performed, it is more effective to perform in the second state. Therefore, according to the present embodiment, the air supply is performed by setting the second state when supplying air. The effect of reducing water pressure pulsation can be enhanced.

  Here, in FIG. 9, air supply is performed in a state where the inner member 10 covers the through-hole 11 (second state (no-hole state)) under a relatively large hydraulic pulsation during partial load operation. It is the figure which compared the hydraulic pressure pulsation in the case of supplying air in the state (1st state (state with a hole)) which the inner member 10 does not cover the through-hole 11 in the case. In FIG. 9, the horizontal axis indicates the amount of air supplied from the main shaft 7 to the inner member 30, and the vertical axis indicates water pressure pulsation.

  As shown in FIG. 9, the water pressure pulsation is reduced by supplying air through the main shaft 7 and the inner member 30 in both the second state and the first state, but in a region where the air supply amount is small, It can be seen that the hydraulic pulsation is suppressed in the second state. FIG. 9 also shows that the effect of reducing water pressure pulsation due to air supply can be increased by supplying air in the second state.

  According to the second embodiment described above, the hydraulic pulsation can be reduced by providing the extension member 10 on the rotating shaft side of the runner main body 4M of the runner 41. Such an extension member 10 is provided apart from the position where the swirling water flow passes in the suction pipe 5, thereby suppressing the occurrence of water flow separation loss in the suction pipe 5. Therefore, it is possible to reduce the hydraulic pulsation while effectively suppressing the decrease in efficiency.

  In the present embodiment, the hydraulic pulsation can be easily reduced by connecting the inner peripheral region In and the outer peripheral region Ex through the through hole 11 of the extension member 10 without supplying air. In addition, it is possible to reduce water pressure pulsation by supplying air. In addition, when supplying air, the effect of reducing water pressure pulsation by supplying air can be enhanced by setting the second state.

  More specifically, when the pressure in the inner peripheral region In is equal to or higher than a predetermined pressure during partial load operation, the through hole 11 of the extension member 10 is not supplied to the inner peripheral region In and the outer peripheral side without performing air supply. By communicating with the region Ex, water pressure pulsation is reduced, and when the pressure in the inner peripheral region In is lower than a predetermined pressure during partial load operation, air supply is performed to reduce the water pressure pulsation. . In general, when a spiral vortex swings greatly, the pressure of the vortex core decreases. For this reason, in the present embodiment, when the pressure in the inner peripheral region In is lower than a predetermined pressure during partial load operation, it is assumed that the spiral vortex swings greatly, and the air supply is performed. Like to do. This makes it possible to effectively reduce the water pressure pulsation when the spiral vortex swings greatly by supplying air.

  And the runner 42 of this Embodiment is the drive part 32 which moves the inner side member 30 from a 1st state to a 2nd state, when the pressure of the inner peripheral area | region In becomes smaller than a predetermined pressure. Is further provided. As a result, when the pressure in the inner circumferential side region In is greater than or equal to a predetermined pressure during partial load operation, the through-hole 11 of the extension member 10 connects the inner circumferential side region In and the outer circumferential side region Ex without performing air supply. It is possible to automatically switch between reducing the hydraulic pulsation by communicating or reducing the hydraulic pulsation by supplying air when the pressure in the inner peripheral region In is low during partial load operation. . For this reason, according to the present embodiment, the hydraulic pulsation can be effectively reduced when the spiral vortex swings greatly at an appropriate timing automatically by the drive unit 32, so that convenience is improved. Can do.

  In the second embodiment, the communication hole 31 is formed in the inner member 30, but the communication hole 31 is not formed as long as a sufficient amount of movement of the inner member 30 along the rotation axis O can be secured. May be. That is, for example, a position where the wall portion of the inner member 30 does not overlap all the through holes 11 of the outer member 20 and a position where the wall portion of the inner member 30 overlaps all the through holes 11 of the outer member 20 in the radial direction. If the inner member 30 is configured to be movable between the gaps, the same effects as those of the second embodiment can be obtained even when the communication hole 31 is not provided.

(Third embodiment)
Next, a runner 43 according to a third embodiment will be described with reference to FIG. In the present embodiment, the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals. In the following, differences from the first embodiment and the second embodiment will be mainly described.

  Similar to the second embodiment, in the present embodiment, as shown by an arrow α in FIG. 10A, the runner 43 passes through the main shaft 7 (not shown) and the inner member 30, and is downstream of the runner body 4M. It is possible to supply air to the side. On the other hand, as shown to FIG. 10 (A), the point from which the outer member 20 is formed in the truncated cone shape extended on the extension line of the front-end | tip part of runner cone 4D differs from 2nd Embodiment. Further, an enlarged portion 30C that is widened in a truncated cone shape is formed at the tip of the inner member 30, and the inner member 30 is different from the second embodiment in that no communication hole is formed. .

  Also in this embodiment, the inner member 30 is movable along the rotation axis O. Specifically, as shown in FIG. 10 (A), the inner member 30 has an enlarged portion 30C that covers the through hole 11 of the outer member 20 from the inner peripheral side (second state), and FIG. 10 (B). As shown in FIG. 4, the enlarged portion 30C is not covered with the through hole 11 and is separated from the through hole 11, and the through hole 11 communicates with the inner peripheral side region In and the outer peripheral side region Ex (first state). As you can see, it is movable. Further, as in the second embodiment, when the pressure in the inner peripheral side region In on the inner peripheral side of the inner member 30 becomes smaller than the predetermined pressure, the inner member 30 in FIG. It moves to the suction pipe 5 side from the state as shown in FIG. 10 (A).

  According to the third embodiment described above, since the inner member 30 is separated from the outer member 20 in the first state, the communication hole 31 described in the second embodiment (see FIG. 6), the same effect as in the second embodiment can be obtained.

(Fourth embodiment)
Next, a runner 44 according to a fourth embodiment will be described with reference to FIG. The same components as those in the first to third embodiments in the present embodiment are denoted by the same reference numerals. Hereinafter, differences from the first to third embodiments will be mainly described.

  In the present embodiment, as in the second embodiment, the runner 44 feeds air toward the downstream side of the runner body 4 through the inner peripheral side region In on the inner peripheral side of the main shaft 7 and the inner member 30. It is possible to do. However, the configuration of the drive unit 32 and the configuration of the air supply path are different from those of the second embodiment. Among these, the drive part 32 of this Embodiment has the mechanism (water pressure movement mechanism 70) which moves the inner member 30 with the water pressure of the water of the upstream of the runner main body 4M seeing in the flow direction of a water flow. Hereinafter, the drive unit 32 of the present embodiment will be described.

  The drive unit 32 of the present embodiment has a disk-shaped fixed plate portion 63A whose outer peripheral portion is fixed to the inner peripheral surface of the main shaft 7, and an outer dimension extending from the center of the fixed plate portion 63A toward the suction pipe 5 side. A cylindrical central shaft portion 63B that is smaller than the outer dimension of the fixed plate portion 63A, and a radial projection from the tip of the central shaft portion 63B, and an outer peripheral portion thereof is located away from the inner peripheral surface of the main shaft 7 in the radial direction. It has a main shaft fixing portion 63 having a disc-shaped tip plate portion 63C.

  In the center of the main shaft fixing portion 63, an air circulation hole 63D that penetrates the fixing plate portion 63A, the central shaft portion 63B, and the tip plate portion 63C is formed along the rotation axis O. The main shaft fixing portion 63 forms a hydraulic chamber 63E between the fixing plate portion 63A and the tip plate portion 63C and on the outer peripheral side of the central shaft portion 63B, and between the tip plate portion 63C and the main shaft 7. A receiving hole 63F for inserting the inner member 30 is formed between the inner peripheral surface and the inner peripheral surface.

  An annular piston member 64 is slidably fitted to the central shaft portion 63B, and the piston member 64 can move in the hydraulic chamber 63E along the axial direction of the rotary shaft O. . Then, an urging member 37 similar to that of the second embodiment is provided in one space of the hydraulic chamber 63E partitioned by the piston member 64 (a space above the paper surface). The biasing member 37 is connected to the piston member 64 and the fixed plate portion 63A.

  In the present embodiment, the inner member 30 is formed long in the axial direction, and the proximal end of the inner member 30 passes through the receiving hole 63F and is fixed to the piston member 64. A disc-shaped closing plate 65 is provided in a portion of the inner member 30 located inside the runner cone 4D. The biasing member 37 biases the inner member 30 so that the peripheral edge 4CA of the center opening of the crown 4C is closed by the outer peripheral portion of the surface of the closing plate 65 facing the main shaft 7 side. It has become. In the present embodiment, when the peripheral edge 4CA of the central opening of the crown 4C is closed by the closing plate 65, as shown in FIG. 11, each of the plurality of communication holes 31 of the inner member 30 is an outer member. The first state overlaps any one of the plurality of 20 through holes 11 in the radial direction.

  Also in the present embodiment, when the pressure in the inner peripheral side region In of the inner member 30 on the suction pipe 5 side with respect to the closing plate 65 becomes smaller than a predetermined pressure, the urging member 37 extends and a plurality of Each of the communication holes 31 is configured to be in a second state that is out of a state where it overlaps with any of the plurality of through holes 11 of the outer member 20 in the radial direction. In this second state, air supply (natural intake) is performed toward the inside of the suction pipe 5 through the inner member 30. Here, the inner member 30 is formed with air circulation holes 30 </ b> A on one side and the other side in the axial direction of the closing plate 65.

  When the air is supplied, the air passes through the inner peripheral side region In of the inner member 30 through the inner peripheral side of the main shaft 7, the air circulation hole 63 </ b> D, the central opening of the crown 4 </ b> C and the air circulation hole 30 </ b> A of the inner member 30. Flow into. That is, the inner peripheral side of the main shaft 7, the air circulation hole 63D, the central opening of the crown 4C, and the air circulation hole 30A of the inner member 30 form an air supply path during supply. As described above, the runner 44 of the present embodiment also sucks out through the inner peripheral side of the main shaft 7 and the inner peripheral side region In of the inner member 30 when the pressure in the inner peripheral region In becomes smaller than a predetermined pressure. Air supply (natural air supply) is performed toward the downstream side of the pipe 5, that is, the runner body 4M.

  On the other hand, in the present embodiment, a water channel 66 that allows one space of the hydraulic chamber 63E partitioned by the piston member 64 to communicate with the outside is formed, and the water channel 66 and the casing 1 are connected by a pipe 67. The pipe 67 is provided with an opening / closing valve 68. In the present embodiment, by opening the opening / closing valve 68, the water in the casing 1 can be guided to the water pressure chamber 66E through the water channel 66, and the inner member 30 can be forcibly moved to the suction pipe 5 side. It has become.

  According to the fourth embodiment described above, the same effects as those of the second embodiment can be obtained, and the inner member 30 is forcibly moved to the suction pipe 5 side by opening the opening / closing valve 38E. Can be made. Thereby, since air can be supplied at an arbitrary timing, the hydraulic pulsation can be more effectively reduced.

(Fifth embodiment)
Next, a runner 45 according to a fifth embodiment will be described with reference to FIG. The same components as those in the first to fourth embodiments in the present embodiment are denoted by the same reference numerals. In the following, differences from the first to fourth embodiments will be mainly described.

  In the present embodiment, the extension member 10 supplies air toward the downstream side of the runner body 4M through the inner peripheral side region In of the main shaft 7 and the inner member 30 as in the second embodiment. It is possible to do. On the other hand, the inner member 30 can be rotated around the rotation axis O.

  FIG. 12 shows a state in which each of the plurality of communication holes 31 formed in the inner member 30 overlaps with one of the plurality of through holes 11 formed in the outer member 20 in the radial direction, that is, the first state. Has been.

  The present embodiment is different from the second embodiment in that the drive unit 32 is a servo motor. In the present embodiment, the drive member 32 that is a servo motor causes the inner member 30 to be in a state in which each of the communication holes 31 overlaps any one of the through holes 11 in the radial direction, so that the through hole 11 has an inner circumference. The first state in which the side region In and the outer peripheral side region Ex communicate with each other and the state in which each of the communication holes 31 overlaps any of the through holes 11 in the radial direction, and the wall portion of the inner member 30 penetrates. It is configured to be able to rotate and move in the circumferential direction of the rotary shaft O so as to take a second state in which the hole 11 is covered from the inner peripheral side. Further, in the present embodiment, the drive unit 32 adjusts the rotational position of the inner member 30 in conjunction with the opening of the guide vane 3, that is, moves to the first state or the second state. ing. Specifically, the guide vane 3 is connected to the servo motor 3M and rotated by driving the servo motor 3M. The rotation of the servo motor 3M is controlled by the control unit 3S. The control unit 3S is electrically connected to the drive unit 32. In response to a command from the control unit 3S, the drive unit 32 links the inner member 30 with the opening degree of the guide vane 3. The state is moved to the first state or the second state.

  According to the fifth embodiment described above, the hydraulic pulsation can be reduced by providing the extension member 10 on the rotating shaft side of the runner body 4M of the runner 41. Such an extension member 10 is provided apart from the position where the swirling water flow passes in the suction pipe 5, thereby suppressing the occurrence of water flow separation loss in the suction pipe 5. Therefore, it is possible to reduce the hydraulic pulsation while effectively suppressing the decrease in efficiency.

  Further, according to the fifth embodiment, the through-hole 11 of the extension member 10 communicates the inner peripheral side region In and the outer peripheral side region Ex without performing air supply, so that the water pressure can be simply set. The pulsation can be reduced, and the hydraulic pulsation can be reduced by supplying air. In addition, when supplying air, the effect of reducing water pressure pulsation by supplying air can be enhanced by setting the second state.

  The runner 45 of the present embodiment further includes a drive unit 32 that moves the inner member 30 to the first state or the second state according to the opening degree of the guide vane 3. Thereby, according to the opening degree of the guide vane 3, a 1st state or a 2nd state can be switched automatically. Thereby, the first state or the second state can be automatically switched at an appropriate timing, for example, an operation such as automatically switching to the second state at a predetermined flow rate during partial load operation. Can be implemented. The relationship between the rotation position of the inner member 30 and the opening degree of the guide vane 2 is preferably determined in advance based on experiments or the like.

  In the second to fourth embodiments, the inner member 30 moves along the rotation axis O in accordance with the pressure in the inner peripheral region In, but this configuration is the fifth embodiment. As described above, the inner member 30 may be moved along the rotation axis O in accordance with the opening degree of the guide vane 3. In this case, for example, in the second and third embodiments, the urging member 37 and the like are deleted from the drive unit 32 and, for example, a servo motor is provided, so that the inner side according to the opening degree of the guide vane 3 is provided. What is necessary is just to set it as the structure etc. to which the member 30 is moved. Further, in the fourth embodiment, the opening / closing valve 68 and the opening degree of the guide vane 3 may be interlocked.

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

1 casing, 2 stay vanes, 3 guide vanes, 4A runner blades, 4B band, 4C crown, 4CA peripheral edge, 4D runner cone, 4M runner body, 5 suction pipe, 7 main shaft, 8 generator, 10 extension member, 11 through hole, 20 Outer member, 30 Inner member, 30A Air flow hole, 30C Enlarged part, 31 Communication hole, 32 Drive part, 33 Guide plate, 33A Through hole, 33B Air flow hole, 34 Rod part, 35 Closing plate, 36 Energizing member Holding plate, 37 urging member, 41, 42, 43, 44, 45 runner, 63 main shaft fixing portion, 63A fixing plate portion, 63B central shaft portion, 63C tip plate portion, 63D air flow hole, 63E water pressure chamber, 63F Receiving hole, 64 piston member, 65 closing plate, 66 water channel, 67 piping, 68 open / close valve, 1 0 Francis turbine, In the peripheral region, Ex outer peripheral side region.

Claims (9)

A runner body that is driven to rotate around the rotation axis by a water flow that flows from the outer periphery during water turbine operation;
A cylindrical extension member provided coaxially with the rotary shaft on the rotary shaft side of the runner main body and extending toward the downstream side of the runner main body,
The extension member is provided with a plurality of through-holes communicating between the inner peripheral side region and the outer peripheral side region thereof. The extension member includes a cylindrical outer member and a cylindrical inner member disposed on the inner peripheral side of the outer member, and the inner peripheral region is formed on the inner peripheral side of the inner member. The outer peripheral side region is formed on the outer peripheral side of the outer member,
The through hole is formed in the outer member,
The inner member has a first state in which the through hole communicates the inner peripheral side region and the outer peripheral side region without covering the through hole from the inner peripheral side at the wall portion, and the wall portion, It is configured to be movable along the axial direction of the rotating shaft so as to take a second state of covering the through hole from the inner peripheral side,
In the second state, air is supplied toward the downstream side of the runner body through the inner peripheral region formed on the inner peripheral side of the inner member. The hydraulic machine runner according to claim 1. The inner member is formed with a plurality of communication holes penetrating in the radial direction,
In the first state, each of the plurality of communication holes of the inner member overlaps with any of the through holes of the outer member, and the through holes are in the inner peripheral region and the outer peripheral side. Communicate with the area,
In the second state, each of the plurality of communication holes of the inner member is removed from a state where it overlaps with any of the through holes of the outer member, and the wall portion of the inner member covers the through holes. The runner of a hydraulic machine according to claim 2, wherein   And a drive unit that moves the inner member from the first state to the second state when the pressure in the inner peripheral region becomes lower than a predetermined pressure. The runner of a hydraulic machine according to claim 2 or 3.   5. The hydraulic machine runner according to claim 4, wherein the drive unit includes a hydraulic pressure moving mechanism that moves the inner member by water pressure upstream of the runner main body.   The hydraulic machine runner according to claim 5, wherein the hydraulic pressure movement mechanism further includes an open / close valve that switches whether the inner member is moved by the hydraulic pressure of water.   A drive unit that moves the inner member to the first state or the second state according to an opening degree of a guide vane disposed on the upstream side of the runner body, The runner of a hydraulic machine according to claim 2 or 3. The extension member includes a cylindrical outer member and a cylindrical inner member disposed on the inner peripheral side of the outer member, and the inner peripheral region is formed on the inner peripheral side of the inner member. The outer peripheral side region is formed on the outer peripheral side of the outer member,
The through hole is formed in the outer member,
The inner member is formed with a communication hole penetrating in the radial direction,
The inner member is in a state in which each of the communication holes overlaps any one of the through holes, and the first state in which the through holes communicate the inner peripheral side region and the outer peripheral side region; Rotating and moving in the circumferential direction of the rotating shaft so that each of the holes is removed from a state where it overlaps one of the through holes, and the wall portion takes a second state of covering the through hole from the inner peripheral side. Configured to be possible,
In the second state, air is supplied toward the downstream side of the runner body through the inner peripheral region formed on the inner peripheral side of the inner member. The hydraulic machine runner according to claim 1.   A drive unit that moves the inner member to the first state or the second state according to an opening degree of a guide vane disposed on the upstream side of the runner body, The runner of a hydraulic machine according to claim 8.

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