Movable guide vane and water turbine

Abstract

The embodiment of the application provides an activity guide vane and a water turbine, and belongs to the technical field of water turbines, and comprises a guide vane body, the guide vane body comprises a main body part and an end face part, wherein the outer contour edge line of the end face part is not coincident with the outer contour edge line of the main body part, and the outer contour edge line of the end face part is deflected by a target angle relative to the outer contour edge line of the main body part in a first direction; the main body part comprises a first end and a second end, the end face part comprises a third end and a fourth end; the distance between the third end and the fourth end is greater than the distance between the first end and the second end. Through the activity guide vane and the water turbine provided by the embodiment of the application, the leakage vortex generated by the end face gap of the activity guide vane under the small opening condition of the unit can be reduced.

Description

Technical Field

[0001] This application relates to the field of water turbine technology, and more specifically, to a movable guide vane and a water turbine. Background Technology

[0002] Hydraulic machinery mainly includes water turbines and water pumps. A water turbine is a power machine that converts the energy of flowing water into rotational mechanical energy; it belongs to the category of turbine machinery within fluid machinery. As early as around 100 BC, a rudimentary form of water turbine—the waterwheel—appeared in China, used for irrigation and driving grain processing equipment. Modern water turbines are mostly installed in hydroelectric power stations to drive generators. In a hydroelectric power station, water from the upstream reservoir is drawn to the water turbine through a water intake pipe, driving the turbine runner to rotate and powering the generator. The water that has performed its work is then discharged downstream through a tailrace pipe. The higher the water head and the greater the flow rate, the greater the output power of the water turbine.

[0003] Hydraulic turbines can be broadly classified into two categories based on their working principle: impulse turbines and reaction turbines. In an impulse turbine, the runner rotates due to the impact of the water flow; the water pressure remains constant during operation, and the primary function is the conversion of kinetic energy. In a reaction turbine, the runner rotates due to the reaction force of the water flow; both the pressure energy and kinetic energy of the water change during operation, but the primary function is the conversion of pressure energy. Impulse turbines can be further classified into two types based on the direction of the water flow: tangential (also known as bucket turbine) and oblique-impact turbine. The structure of an oblique-impact turbine is basically the same as that of a bucket turbine, except that the jet direction has an angle; it is only used in small units.

[0004] One of the key components of a water turbine is the movable guide vane, which controls the flow direction and flow rate at the runner inlet, thereby achieving efficient and stable operation. During operation, leakage vortices inevitably arise from the movable guide vane's vertical clearance and its end face clearance. Leakage vortices in the vertical clearance are primarily caused by flow separation at the leading or trailing edge of the guide vane. Leakage vortices in the end face clearance are induced by the difference in flow direction between the flow in the guide vane end face clearance and the mainstream flow.

[0005] Currently, because the sealing groove only exists when the movable guide vane is fully closed, the end-face seal almost disappears once the movable guide vane is open. This means that the movable guide vane end-face sealing technology can only solve the leakage vortex problem when the movable guide vane is fully closed. For a large opening, the flow direction in the movable guide vane end-face gap is close to the mainstream flow direction, so even if leakage occurs, no significant leakage vortex will be generated. However, once the unit is operating at or past a small opening of the movable guide vane, the sealing strip is insufficient to suppress the flow in the guide vane end-face gap and the leakage vortex caused by its difference from the mainstream flow direction. Summary of the Invention

[0006] This application provides a movable guide vane, which aims to reduce leakage vortices generated by the gap between the end faces of the movable guide vane when the unit is operating at a small opening.

[0007] The first aspect of this application provides a movable guide vane, including:

[0008] Guide vane body, the guide vane body comprising a main body portion and an end face portion;

[0009] Wherein, the outer contour line of the end face portion does not coincide with the outer contour line of the main body portion, and the outer contour line of the end face portion is deflected by a target angle relative to the outer contour line of the main body portion in the first direction.

[0010] The main body portion includes a first end and a second end, and the end face portion includes a third end and a fourth end;

[0011] The distance between the third end and the fourth end is greater than the distance between the first end and the second end.

[0012] Optionally, the target angle is 2°.

[0013] Optionally, the distance between the first end and the second end is the first distance, and the distance between the third end and the fourth end is the second distance;

[0014] Wherein, the second distance exceeds the first distance by 1.5% of the first distance.

[0015] Optionally, the end face portion is provided with a plurality of converging stripes, and the plurality of converging stripes are arranged parallel to each other;

[0016] The converging stripe includes a first stripe and a second stripe that are connected together. The connection between the first stripe and the second stripe forms a pointed portion, which is positioned from the third end toward the fourth end.

[0017] Optionally, the angle between the first stripe and the second stripe is greater than or equal to 15° and less than or equal to 60°.

[0018] Optionally, the end face is provided with a plurality of converging grooves, and the converging stripe is formed between two adjacent converging grooves.

[0019] Optionally, the depth of the converging groove is greater than or equal to 10 μm and less than or equal to 50 μm.

[0020] A second aspect of this application provides a water turbine, comprising:

[0021] The volute, the impeller, and a plurality of fixed guide vanes and a plurality of movable guide vanes as provided in the first aspect of the embodiments of this application, arranged around the impeller;

[0022] The movable guide vane is positioned closer to the rotor.

[0023] Optionally, the ratio between the diameter of the distribution circle of the movable guide vane and the inlet diameter of the runner is greater than or equal to 1.2 and less than or equal to 1.3.

[0024] Optionally, the turbine further includes a top cover and a bottom ring, with the movable guide vanes located between the top cover and the bottom ring;

[0025] The end face of the movable guide vane is provided with multiple converging stripes;

[0026] The top cover has multiple diverging stripes positioned relative to the movable guide vane, with the tips of the converging stripes facing in the opposite direction to the tips of the diverging stripes.

[0027] Beneficial effects:

[0028] This application provides a movable guide vane. By setting a guide vane body, the guide vane body includes a main body and an end face. The outer contour line of the end face does not coincide with the outer contour line of the main body, and the outer contour line of the end face is deflected relative to the outer contour line of the main body by a target angle in a first direction. The distance from the third end to the fourth end of the end face is greater than the distance from the first end to the second end of the main body. In this way, when the unit is in a small opening condition, the torsion of the outer contour line of the end face causes the main flow direction of the water flow near the end face to shift towards the gap flow direction, thereby making the water flow direction near the end face of the movable guide vane closer to the main flow direction, and thus fully suppressing the leakage vortex. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a movable guide vane according to an embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the structure of the outer contour line of the main body and the outer contour line of the end face in an embodiment of this application;

[0032] Figure 3 This is a schematic diagram of a movable guide vane with converging stripes according to an embodiment of this application;

[0033] Figure 4 This is a schematic diagram of the converging stripes in an active guide vane according to an embodiment of this application;

[0034] Figure 5 This is a schematic diagram of the structure of a water turbine according to an embodiment of this application;

[0035] Figure 6 This is a schematic diagram of the structure of a water turbine including movable guide vanes, an upper crown cavity, and a lower annular cavity, according to an embodiment of this application.

[0036] Explanation of reference numerals in the attached drawings: 10, movable guide vane; 101, main body; 1011, first end; 1012, second end; 102, end face; 1021, third end; 1022, fourth end; 103, converging stripes; 1031, first stripe; 1032, second stripe; 20, volute; 30, impeller; 40, fixed guide vane; 50, upper crown cavity; 60, lower annular cavity. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] In related technologies, there are already sufficient optimization solutions for the vertical clearance of movable guide vanes. For example, the Chinese patent document with patent application number CN201310513581.4, entitled "A New Method for Optimizing the Vertical Clearance of Movable Guide Vanes of Hydropower Turbines Based on Finite Element Analysis", adopts the design of guide vane profile based on flow simulation results to optimize the vertical clearance and thus reduce leakage vortices.

[0039] Currently, optimization solutions for guide vane end face clearance mainly focus on wear control of guide vane end face clearance in large mixed-flow turbines. For example, the Chinese patent document "New Anti-Abrasion Guide Vane Structure for Water Turbines" with patent application number CN94227330.3 reduces gap flow and increases the wear resistance of the guide vane end face by setting elastic skirts at both ends of the guide vane.

[0040] For example, the Chinese patent document with patent application number CN201911085617.7, entitled "A Sealing Structure for the End Face of a Movable Guide Vane of a Water Turbine," shows that the sealing effect of the end face of the movable guide vane can be adjusted by the medium pressure.

[0041] For example, the Chinese patent document with patent application number CN201521122607.3, entitled "An end face leak-proof device for a water turbine movable guide vane", describes how multiple sealing grooves are set to allow the copper block with self-compensating ability to be worn down, thereby reducing the impact of flow in the end face gap.

[0042] However, these existing technologies cannot solve the leakage vortex problem in the clearance between the guide vane end faces when the guide vane is open. Since the sealing groove only exists when the movable guide vane is fully closed, the end face seal almost disappears once the movable guide vane is open. In other words, the guide vane end face sealing technology can only solve the leakage vortex problem when the movable guide vane is fully closed. For the large opening state, the flow in the guide vane end face clearance is close to the mainstream direction, so even if leakage occurs, no vortex will be generated. However, once the unit is operating at or past the small opening state of the guide vane, the sealing strip is insufficient to suppress the leakage vortex caused by the flow in the guide vane end face clearance and its difference from the mainstream direction.

[0043] Meanwhile, the relevant technologies cannot solve the leakage vortex problem in pumped storage units. In large mixed-flow units with significant silt abrasion at the guide vane end face clearance, the leakage vortex intensity is not high. On the one hand, silt obstructs the end face clearance, reducing the leakage flow rate; on the other hand, solid particles dissipate the leakage vortex. However, in newly built pumped storage units in recent years, the water quality is better, with little silt deposition. Therefore, the flow at the guide vane end face clearance and the resulting leakage vortex are actually more severe.

[0044] Meanwhile, according to the Chinese patent application number CN201710339456.4, "A method to mitigate the harm of pressure pulsation in the bladeless zone of a mixed-flow pump turbine", it can be known that pumped storage units are small in size and have low movable guide vane height. Therefore, leakage vortices originating from the guide vane end face gap are more obvious than leakage vortices originating from the gap between the guide vane vertical surfaces.

[0045] In view of this, this application proposes an active guide vane. By setting a guide vane body, the guide vane body includes a main body and an end face. The outer contour line of the end face does not coincide with the outer contour line of the main body, and the outer contour line of the end face is deflected by a target angle relative to the outer contour line of the main body in a first direction. Moreover, the distance from the third end to the fourth end of the end face is greater than the distance from the first end to the second end of the main body. In this way, when the unit is in a small opening condition, the torsion of the outer contour line of the end face causes the main flow direction of the water flow near the end face to shift towards the gap flow direction, thereby making the water flow direction near the end face of the active guide vane closer to the main flow direction, and thus fully suppressing the leakage vortex.

[0046] Reference Figure 1 As shown, this application discloses a movable guide vane 10, which can be applied to water turbines (including pumped storage units, mixed flow units, etc.). The movable guide vane 10 includes a guide vane body, which in turn includes a main body portion 101 and an end face portion 102.

[0047] Specifically, the main body 101 is the main component of the guide vane body. The cross-sectional outer contour of the main body 101 is roughly an ellipse. The ellipse includes two arc-shaped edges and one circular arc edge. The two arc-shaped edges are connected to the two ends of the circular arc edge, and the ends of the two arc-shaped edges away from the circular arc edge are connected to each other.

[0048] Reference Figure 2 As shown in the embodiment of this application, the main body 101 includes a first end 1011 and a second end 1012. The first end 1011 is the end where the arc edge line is located. Usually, the first end 1011 is also the leading edge end of the guide vane body, that is, the end facing the direction of the water flow. The second end 1012 is the end where the two arc edge lines are connected. Usually, the second end 1012 is also the trailing edge end of the guide vane body, that is, the end away from the direction of the water flow.

[0049] Reference Figure 1 As shown, the main body 101 includes two end faces, which can also be understood as the top and bottom surfaces of the guide vane body. In this embodiment, both the top and bottom surfaces are end face portions 102 of the guide vane body. Furthermore, in this embodiment, the outer contour line of the end face portion 102 does not coincide with the outer contour line of the main body 101.

[0050] Specifically, the end face portion 102 also includes two arc-shaped edge lines and one circular arc edge line. However, in the projection along the height direction of the guide vane body, the two arc-shaped edge lines and the circular arc edge line of the end face portion 102 do not coincide with the two arc-shaped edge lines and the circular arc edge line of the main body portion 101.

[0051] Reference Figure 2 As shown in this embodiment, the outer contour line of the end face portion 102 is deflected by a target angle relative to the outer contour line of the main body portion 101 in a first direction. The first direction refers to the direction in which the movable guide vane 10 is perpendicular to the turbine runner 30. The turbine runner 30 is a major component of the turbine, and the movable guide vane 10 is arranged around the runner 30. The direction in which the movable guide vane 10 is perpendicular to the runner 30 can be roughly understood as the diameter direction of the runner 30.

[0052] Specifically, the outer contour line of the end face portion 102 and the outer contour line of the main body portion 101 have two intersection points. To the left of these two intersection points, the outer contour line of the end face portion 102 deflects away from the rotating wheel 30, and to the right of these two intersection points, the outer contour line of the end face portion 102 deflects towards the rotating wheel 30. Thus, the outer contour line of the end face portion 102 and the outer contour line of the main body portion 101 do not coincide, and the two have an intersection point.

[0053] With this design, when the unit is operating at a small opening, the overall direction of the end face 102 is deflected, so the water flow direction in the gap between the end faces of the movable guide vane 10 will be closer to the mainstream water flow direction, thereby reducing the angle difference between the two water flows, reducing the angular velocity of the leakage vortex, thereby reducing the intensity of the leakage vortex and suppressing the leakage vortex.

[0054] Furthermore, in this embodiment of the application, the target angle is 2°.

[0055] Specifically, since the opening of the movable guide vane 10 is generally 10% when the hydraulic resonance caused by the leakage vortex is most pronounced, the target angle by which the outer contour line of the end face portion 102 deflects relative to the outer contour line of the main body portion 101 in the first direction is 2°. For the pumped storage unit described in this application embodiment, the angle range from the fully closed movable guide vane to the rated opening of the movable guide vane is approximately 20°, and this value has a certain degree of universality. Therefore, when the unit output is 10%~20% (when the hydraulic vibration is most pronounced), the opening of the movable guide vane roughly corresponds to 2°~4° (related to the governor configuration), and a deflection target angle of 2° can ensure a certain range spanning 2°~4°.

[0056] Furthermore, for other types of units or units with significantly different dimensions and sizes compared to conventional pumped storage units, the steps for determining the target angle are as follows: (1) Determine the unit output range where the hydraulic resonance caused by the leakage vortex is most pronounced. This can be determined through on-site testing or CFD numerical simulation; (2) Determine the corresponding active guide vane angle ranges θ1 and θ2 for this output range. The basis for this determination should be the governor's design data; (3) The minimum target deflection angle is θ2-θ1. If the effect of reducing leakage is not significant, it can be increased by 1-2°.

[0057] Furthermore, due to the deflection of the outer contour edge of the end face portion 102 of the guide vane body, the position of the end face cannot be completely closed when the movable guide vane 10 is fully closed. In order to ensure the closing effect between the movable guide vanes 10, the outer contour edge of the end face portion 102 is extended in this embodiment of the application.

[0058] Specifically, refer to Figure 2 As shown, the end face portion 102 includes a third end 1021 and a fourth end 1022. The third end 1021 is the end of the arcuate edge of the outer contour of the end face portion 102, corresponding to the leading edge of the main body portion 101. The fourth end 1022 is the connecting end of the two arcuate edges of the outer contour of the end face portion 102, corresponding to the trailing edge of the main body portion 101. Furthermore, the distance between the third end 1021 and the fourth end 1022 is greater than the distance between the first end 1011 and the second end 1012, thus making the arcuate edge of the end face portion 102 longer. This is equivalent to extending the trailing edge of the end face portion 102 by a portion, allowing the end face portions 102 of two adjacent movable guide vanes 10 to achieve better closure.

[0059] In this embodiment of the application, the distance between the first end 1011 and the second end 1012 is the first distance, and the distance between the third end 1021 and the fourth end 1022 is the second distance;

[0060] The second distance exceeds the first distance by about 1.5% of the first distance. In other words, the extension distance of the outer contour line of the end face portion 102 is approximately 1.5% of the outer contour line of the main body portion 101.

[0061] It should be noted that the extent by which the second distance exceeds the first distance is a passive dimension, which is related to the geometry of the guide vane's outer contour edge and the target deflection angle of the outer contour edge. Specifically, the extent by which the second distance exceeds the first distance depends on how much the second distance extends until there are no gaps on the end face of the fully closed movable guide vane. Generally speaking, the larger the target deflection angle, the longer the second distance extends. In this embodiment, the outer contour edge of the end face portion 102 is deflected by 2°, therefore the extent by which the second distance exceeds the first distance is approximately 1.5% of the first distance.

[0062] Furthermore, the movable guide vane 10 also includes two guide vane arms 104, which are located on the two end faces (top and bottom) of the main body 101, respectively, and the two guide vane arms 104 are rotatably connected to the top cover 50 and the bottom ring 60 in the turbine, so that the guide vane body can rotate relative to the runner 30.

[0063] The movable guide vane 10 provided in this application embodiment causes the outer contour edge of the end face portion 102 of the guide vane body to deflect relative to the outer contour edge of the main body portion 101, so that the flow direction of the main water flow near the end face portion 102 can be shifted to the flow direction of the end face gap of the movable guide vane 10, thereby reducing the leakage vortex of the end face gap of the movable guide vane 10.

[0064] It should be noted that, due to the deflection of the outer contour line of the end face portion 102, when applied to a turbine unit, the area between two adjacent movable guide vanes 10 also forms an irregular shape. Therefore, the sealing strip between two adjacent movable guide vanes 10 is no longer a straight sealing strip. The specific shape of the sealing strip needs to be adjusted according to the contact line of the two movable guide vanes 10 when the movable guide vanes 10 are fully closed.

[0065] In one alternative implementation, refer to Figure 3 As shown, this application embodiment also provides a movable guide vane, in which a plurality of converging stripes 103 are provided on the end face portion 102 of the guide vane body.

[0066] Specifically, multiple converging stripes 103 are parallel to each other, and the lines of the converging stripes 103 can include straight lines, curves, or combinations of straight lines and curves, etc. The converging stripe 103 can be formed by machining multiple converging grooves on the end face portion 102. That is, after machining two converging grooves on the end face, the remaining guide vane body between the two converging grooves forms a converging stripe 103.

[0067] Reference Figure 4 As shown in the embodiment of this application, the converging stripe 103 includes a first stripe 1031 and a second stripe 1032 connected to each other, and both the first stripe 1031 and the second stripe 1032 are straight stripes. A pointed portion is formed at the connection between the first stripe 1031 and the second stripe 1032, and on the end face portion 102, the pointed portion is disposed from the third end 1021 toward the fourth end 1022.

[0068] In practical applications, the direction of multiple converging stripes 103 (that is, the center line of the converging stripes 103) should be located between the direction of the water flow and / or the chord line (the arc-shaped edge line in the outer contour edge line) of the movable guide vane 10, and this direction can be adjusted appropriately according to the change of the chord line position.

[0069] Furthermore, the included angle between the first stripe 1031 and the second stripe 1032 is greater than or equal to 15° and less than or equal to 60°. For example, the included angle between the first stripe 1031 and the second stripe 1032 can be 15°, 25°, 35°, 45°, 60°, etc., and those skilled in the art can choose according to actual needs.

[0070] Furthermore, the spacing between two adjacent converging stripes 103 is greater than or equal to 0.1 mm and less than or equal to 1.0 mm. For example, the spacing between two adjacent converging stripes 103 can be 0.1 mm, 0.3 mm, 0.5 mm, 0.7 mm, 1.0 mm, etc., and those skilled in the art can set it according to the size of the turbine unit.

[0071] In practical applications, since the gap between the end faces of the movable guide vane 10 is generally less than 1 mm, machining can easily affect the end face seal. Therefore, the converging stripe 103 should be processed using laser engraving or electrochemical machining methods, that is, the converging groove should be processed using laser engraving or electrochemical machining. The depth of the converging groove is greater than or equal to 10 μm and less than or equal to 50 μm. For example, the depth of the converging groove can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, etc., and those skilled in the art can choose according to the actual situation.

[0072] At the same time, refer to Figure 3 As shown, the converging stripes 103 should be mainly distributed on the end face portion 102 in the area away from the guide vane arm 105, that is, the area near the leading edge and trailing edge. Furthermore, since the gap flow rate is smaller in the area of ​​the end face portion 102 near the guide vane arm 104, the converging stripes 103 in this area can be shallower.

[0073] Through the movable guide vane 10 provided in the embodiments of this application, the converging stripes 103 can significantly increase the thickness of the turbulent boundary layer, compress the formation space of the leakage vortex, and reduce the normal component of the flow velocity, thereby reducing the angular velocity of the leakage vortex. At the same time, the direction of the converging stripes 103 is slightly biased towards the chord line, which can guide the gap flow direction to be closer to the chord line direction, reduce the angle with the mainstream flow direction, and thus reduce the angular velocity of the leakage vortex.

[0074] Furthermore, in one embodiment, in order to further improve the effect of the converging stripe 103, a plurality of diverging stripes can be provided on the top cover and bottom ring of the turbine at positions relative to the end face portion 102 of each movable guide vane 10, and the orientation of the tip portion of the diverging stripe is opposite to the orientation of the tip portion of the converging stripe 103.

[0075] In related technologies, leakage flow is generally blocked by strengthening the end face sealing of the movable guide vane 10. However, when the movable guide vane 10 is open, the end face sealing effect is minimal. This application's embodiment follows the principle of "preferring dredging to blocking," guiding the flow direction in the gap cavity towards the mainstream direction through the converging stripes 103 of the end face portion 102 at a small opening; furthermore, the torsion caused by the deformation of the outer contour of the end face portion 102 shifts the mainstream flow direction near the end face portion 102 towards the gap flow direction. Under these two effects, the flow near the end face portion 102 of the movable guide vane 10 is closer to the mainstream direction when the unit is operating at a small opening, ultimately effectively suppressing the leakage vortex at the operating point where its influence is greatest.

[0076] Based on the same inventive concept, referring to Figure 5 As shown in the figure, this application discloses a water turbine, including a volute 20, a runner 30, and a plurality of fixed guide vanes 40 arranged around the runner 30 and a plurality of movable guide vanes 10 as described above in the embodiments of this application.

[0077] Specifically, the function of the spiral casing 20 is to distribute the water flow evenly around the runner 30. When the water head is below 40 meters, the spiral casing 20 of the turbine is usually cast on site with reinforced concrete; when the water head is above 40 meters, a welded or integrally cast metal spiral casing is usually used.

[0078] Furthermore, the movable guide vane 10 is positioned closer to the rotor 30. It can be understood that the multiple fixed guide vanes 40 and the multiple movable guide vanes 10 each form two circles, with the circle formed by the movable guide vanes 10 located within the circle formed by the fixed guide vanes 40.

[0079] In related technologies, the main hazard of leakage vortices generated by the gap at the end face of the movable guide vane 10 stems from the fact that these vortices induce hydraulic resonance in the upper crown cavity 50 and the lower annular cavity 60. As the flow progresses, the leakage vortices migrate towards the mainstream region.

[0080] Reference Figure 6 As shown in this embodiment, to reduce the impact of leakage vortices on the upper crown cavity 50 and the lower annular cavity 60, the diameter of the distribution circle of the movable guide vane 10 can be increased, thereby moving the starting point of the leakage vortex upstream. However, if the movable guide vane 10 is too far from the inlet of the impeller 30, the guiding effect will be poor, causing other problems. Therefore, the ratio of the diameter of the distribution circle of the movable guide vane 10 to the inlet diameter of the impeller 30 is greater than or equal to 1.2 and less than or equal to 1.3. Here, the diameter of the distribution circle of the movable guide vane 10 refers to the diameter of the circular area formed by the rotation of the movable guide vane.

[0081] Furthermore, the turbine also includes a top cover and a bottom ring, with a receiving area formed between the top cover and the bottom ring. The runner 30 and the movable guide vane 10 are both located between the top cover and the bottom ring, that is, within this receiving area.

[0082] Furthermore, when converging stripes 103 are provided on the end face portion 102 of the movable guide vane 10, multiple diverging stripes can be provided on the top cover and bottom ring at positions relative to the end face portion 102 of each movable guide vane 10. The orientation of the tip portion of the diverging stripes is opposite to the orientation of the tip portion of the converging stripes 103. The diverging stripes can cooperate with the converging stripes on the end face portion 102 of each movable guide vane 10 to further improve the suppression effect of the converging stripes 103 on leakage vortices.

[0083] When a water turbine is used in a pumped-storage unit, the impact of leakage vortices caused by the clearance between the guide vanes 10 and the guide vane end faces is relatively large due to the relatively low height of the guide vanes 10. Especially for small units, the width of the guide vane end face clearance is a higher percentage, which reduces the flow stability of the unit.

[0084] Therefore, the turbine provided in this application embodiment reduces the intensity of the leakage vortex at the guide vane end face, extends the dissipation length of the leakage vortex, and allows it to fully mix with the mainstream water flow before flowing into the runner 30, thereby enhancing the flow stability of the unit and ultimately improving the operational stability of the unit.

[0085] Meanwhile, the hydraulic resonance between the upper crown cavity (50mm gap) and the lower annular cavity (60mm gap) is a significant cause of vibration and noise at the top of the unit. Its inducing characteristics are complex and greatly influenced by the specific geometry of the unit's flow channels. Furthermore, the frequencies of the leakage vortex and the characteristic frequencies of the flow in the gap cavity are both in the lower frequency range. During speed changes, the vortex frequency gradually changes, easily leading to hydraulic resonance with the water in the gap cavity, exacerbating plant vibration and noise. The turbine provided in this application can reduce the impact of leakage vortices and decrease the occurrence of hydraulic resonance, thereby reducing the unit's vibration and noise levels and improving the comfort and efficiency of the production environment.

[0086] It should be noted that although the technical solutions of the embodiments of this application were originally derived from the optimization requirements of pumped storage units, they can still be used for other types of turbine units.

[0087] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0088] It should also be noted that, in this document, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. In the absence of further restrictions, an element defined by the phrase "includes a..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.

[0089] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand this application, and the content of this specification should not be construed as a limitation of this application. Furthermore, for those skilled in the art, there will be different forms of changes in the specific implementation methods and application scope based on this application. It is neither necessary nor possible to exhaustively list all implementation methods here, and obvious changes or modifications derived therefrom are still within the protection scope of this application.

Claims

1. A movable guide vane, characterized in that, include: Guide vane body, the guide vane body comprising a main body portion and an end face portion; Wherein, the outer contour line of the end face portion does not coincide with the outer contour line of the main body portion, and the outer contour line of the end face portion is deflected by a target angle relative to the outer contour line of the main body portion in the first direction. The cross-sectional outer contour of the main body includes two arc-shaped edges and one circular arc edge. The two arc-shaped edges are connected to the two ends of the circular arc edge, and the ends of the two arc-shaped edges away from the circular arc edge are connected to each other. The end face also includes two arc-shaped edges and one circular arc edge. In the projection along the height direction of the guide vane body, the two arc-shaped edges and the circular arc edge of the end face do not coincide with the two arc-shaped edges and the circular arc edge of the main body. The main body portion includes a first end and a second end, and the end face portion includes a third end and a fourth end; The distance between the third end and the fourth end is greater than the distance between the first end and the second end.

2. The movable guide vane according to claim 1, characterized in that: The target angle is 2°.

3. The movable guide vane according to claim 1, characterized in that: The distance between the first end and the second end is the first distance, and the distance between the third end and the fourth end is the second distance; Wherein, the second distance exceeds the first distance by 1.5% of the first distance.

4. The movable guide vane according to claim 1, characterized in that: The end face portion is provided with multiple converging stripes, and the multiple converging stripes are arranged parallel to each other. The converging stripe includes a first stripe and a second stripe that are connected together. The connection between the first stripe and the second stripe forms a pointed portion, which is positioned from the third end toward the fourth end.

5. The movable guide vane according to claim 4, characterized in that: The angle between the first stripe and the second stripe is greater than or equal to 15° and less than or equal to 60°.

6. The movable guide vane according to claim 4, characterized in that: The end face is provided with multiple converging grooves, and the converging stripe is formed between two adjacent converging grooves.

7. The movable guide vane according to claim 6, characterized in that: The depth of the converging groove is greater than or equal to 10 μm and less than or equal to 50 μm.

8. A water turbine, characterized in that, include: A volute, a rotating wheel, and a plurality of fixed guide vanes and a plurality of movable guide vanes as described in any one of claims 1-7; The movable guide vane is positioned closer to the rotor.

9. The water turbine according to claim 8, characterized in that: The ratio between the diameter of the distribution circle of the movable guide vane and the inlet diameter of the runner is greater than or equal to 1.2 and less than or equal to 1.

3.

10. The water turbine according to claim 8, characterized in that: The turbine also includes a top cover and a bottom ring, with the movable guide vanes located between the top cover and the bottom ring; The end face of the movable guide vane is provided with multiple converging stripes; The top cover and the bottom ring are provided with a plurality of diverging stripes relative to the position of the movable guide vane, and the tip of the converging stripe faces in the opposite direction to the tip of the diverging stripe.

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