Movable guide vane and pump turbine

Abstract

The invention discloses a movable guide vane and a pump turbine, and relates to the technical field of pump turbines. The movable guide vane is used for controlling the flow of water guided into the impeller and comprises a guide vane body and a protruding part, and the guide vane body is provided with a first end close to the impeller. The protruding part is arranged on the side, facing the impeller, of the guide vane body in a protruding mode, the protruding part and the first end are arranged in a spaced mode in the length direction of the movable guide vane, and the protruding part is used for adjusting the flow state when water is guided into the impeller. The protruding part is arranged on the side, facing the impeller, of the guide vane body, so that the water flow separation risk of the pump turbine under the small-load working condition can be reduced, vortexes are avoided, pressure pulsation of a vaneless area is reduced, and the operation stability of the pump turbine is improved.

Description

Technical Field

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

[0002] As one of the core components of a water pump turbine, the movable guide vane's core function is to regulate flow rate. Specifically, by changing its rotation angle, the movable guide vane can precisely control the flow rate of water entering the runner, thereby achieving energy conversion.

[0003] Typically, the head of the movable guide vane resembles an airfoil. These guide vanes are designed for ideal operating conditions (ideal operating conditions refer to specific working states that maximize unit efficiency, performance, and stability), under which they effectively guide water flow. However, as the operating range of pump-turbines shifts towards wider or full-load operation, significant flow separation occurs at the head of the movable guide vane under low-load conditions. This leads to increased pressure pulsation in the bladeless zone, thereby reducing the operational stability of the pump-turbine. Furthermore, impurities such as silt carried in the water flow cause impact erosion of the movable guide vane during operation. This not only exacerbates the flow separation problem at the guide vane head but also further amplifies pressure pulsation, resulting in decreased operational stability of the pump-turbine. Summary of the Invention

[0004] The embodiments of this application provide a guide vane and a water pump turbine to at least partially improve the above-mentioned technical problems.

[0005] In a first aspect, embodiments of this application provide a movable guide vane for controlling the water flow rate introduced into an impeller. The movable guide vane includes a guide vane body and a raised portion. The guide vane body has a first end close to the impeller. The raised portion protrudes from the side of the guide vane body facing the impeller. Along the length direction of the movable guide vane, the raised portion is spaced apart from the first end. The raised portion is used to adjust the flow state when water is introduced into the impeller.

[0006] In one possible implementation, the guide vane body and the raised portion are integrally formed.

[0007] In one possible implementation, the length of the guide vane body is L1, the raised portion has a rear end near the first end, and the distance between the rear end and the first end along the length direction of the movable guide vane is L2, satisfying 0.01L1≤L2≤0.04L1; and / or, the raised portion has a front end away from the first end, and the distance between the front end and the first end along the length direction of the movable guide vane is L3, satisfying 0.08L1≤L3≤0.26L1.

[0008] In one possible implementation, the length of the guide vane body is L1, and the dimension of the raised portion along the length direction of the movable guide vane is W, satisfying 0.07L1≤W≤0.22L1.

[0009] In one possible implementation, along the length of the movable guide vane, from the middle to both ends of the guide vane body, the thickness of the guide vane body gradually decreases, and the position where the thickness of the guide vane body is the greatest is the guide vane throat, and the raised portion is located between the guide vane throat and the first end.

[0010] In one possible implementation, the raised portion is spaced apart from the throat of the guide vane along the length direction of the active guide vane.

[0011] In one possible implementation, the distance between the raised portion and the guide vane throat is L4, satisfying 0.24L1≤L4≤0.32L1.

[0012] In one possible implementation, the raised portion does not extend beyond the throat of the guide vane along the width direction of the active guide vane.

[0013] In one possible implementation, the guide vane body has a first surface and a second surface facing the impeller, the raised portion has a third surface facing the impeller, the third surface connects the first surface and the second surface, and the projection curve S1 of the first surface in the thickness direction of the movable guide vane satisfies Bessel equation one:

[0014]

[0015] The projection curve S2 of the third surface in the thickness direction of the movable guide vane satisfies Bessel equation two:

[0016]

[0017] The projection curve S3 of the second surface in the thickness direction of the movable guide vane satisfies Bessel equation three:

[0018]

[0019] Secondly, embodiments of this application provide a water pump turbine, including the aforementioned movable guide vanes.

[0020] The beneficial effects of the embodiments of this application are as follows:

[0021] In the embodiments of this application, by providing a raised portion on the side of the guide vane body facing the impeller, the risk of water flow separation in the pump turbine under low load conditions can be reduced, eddy currents can be avoided, and pressure pulsation in the bladeless zone can be reduced, thereby improving the operational stability of the pump turbine. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0023] Figure 1 A schematic diagram of the active guide vane structure provided for an embodiment of this application;

[0024] Figure 2 A schematic diagram illustrating the lateral extension pattern of the active guide vane structure provided in an embodiment of this application;

[0025] Figure 3 A schematic diagram of the structure of a water pump turbine provided for an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures:

[0027] 100-Active guide vane;

[0028] 10-Guide vane body; 11-First end; 12-Second end; 13-Guide vane throat; 14-First surface; 15-Second surface;

[0029] 20 - Raised portion; 21 - Rear end; 22 - Front end; 23 - Third surface;

[0030] X - Length direction; Y - Width direction;

[0031] 1000 - Water pump turbine;

[0032] 200 - Impeller; 210 - Lower ring; 220 - Blade. Detailed Implementation

[0033] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0034] Typically, the head of a movable guide vane resembles an airfoil. These guide vanes are often designed for optimal operating conditions, where they effectively guide water flow. However, as the operating range of pump-turbines shifts towards wider or full-load operation, significant flow separation occurs at the head of the movable guide vane under low-load conditions. This leads to increased pressure pulsation in the bladeless region, thereby reducing the operational stability of the pump-turbine. Furthermore, impurities such as silt carried in the water flow cause impact erosion to the movable guide vane during operation. This not only exacerbates the flow separation problem at the guide vane head but also further amplifies pressure pulsation, resulting in decreased operational stability of the pump-turbine.

[0035] In view of this, embodiments of this application provide a movable guide vane 100 for controlling the water flow rate of the guide impeller 200.

[0036] Figure 1 A schematic diagram of the active guide vane 100 provided for an embodiment of this application is shown below. Figure 1 In some embodiments, the movable guide vane 100 includes a guide vane body 10 and a raised portion 20. The guide vane body 10 has a first end 11 near the impeller 200. The raised portion 20 protrudes from the side of the guide vane body 10 facing the impeller 200. Along the length direction X of the movable guide vane 100, the raised portion 20 and the first end 11 are spaced apart. The raised portion 20 is used to adjust the flow state when water is introduced into the impeller 200.

[0037] The guide vane body 10 has a positive pressure surface on the side facing away from the impeller 200, where the water flow is smaller and the pressure is higher. Conversely, the guide vane body 10 has a negative pressure surface on the side facing the impeller 200, where the water flow is larger and the pressure is lower. Specifically, the water velocity is higher on the negative pressure surface than on the positive pressure surface, creating a low-pressure zone according to Bernoulli's principle. This low-pressure zone, combined with the high pressure on the positive pressure surface, creates a pressure difference for flow guidance. However, the negative pressure surface is prone to boundary layer separation due to uneven flow velocity, leading to flow separation and eddy currents. This flow separation is particularly problematic under low-load conditions (i.e., low flow rates), exacerbating pressure pulsation in the bladeless zone and affecting the stability of the pump-turbine 1000. The bladeless zone refers to the flow channel formed between two adjacent movable guide vanes 100.

[0038] In this embodiment of the application, by providing a raised portion 20 on the side of the guide vane body 10 facing the impeller 200, the risk of water flow separation of the water pump turbine 1000 under low load conditions can be reduced, eddy current generation can be avoided, thereby reducing pressure pulsation in the bladeless zone and improving the operational stability of the water pump turbine 1000.

[0039] The raised portion 20 is spaced apart from the first end 11, which reduces the resistance of the first end 11 to the water flow, making it easier for the water to leave the bladeless zone and enter the impeller 200, thus reducing energy loss.

[0040] In addition, the protrusion 20 is equivalent to locally thickening the head of the guide vane, which not only improves the structural strength of the guide vane, but also enhances the erosion resistance of the movable guide vane 100.

[0041] In some embodiments, the guide vane body 10 and the raised portion 20 are integrally molded, so that the guide vane body 10 and the raised portion 20 can be manufactured simultaneously, which not only reduces the manufacturing difficulty, but also helps to improve the connection stability of the two.

[0042] In some embodiments, the length of the guide vane body 10 is L1, the raised portion 20 has a rear end 21 close to the first end 11, and the distance between the rear end 21 and the first end 11 along the length direction X of the movable guide vane 100 is L2, satisfying 0.01L1≤L2≤0.04L1.

[0043] For example, L2 can be 0.01L1, 0.015L1, 0.02L1, 0.025L1, 0.03L1, 0.035L1, 0.04L1, and any value in between.

[0044] During the process of the movable guide vane 100 rotating from the open state to the closed state, the raised portion 20 will gradually approach the impeller 200, which may lead to the risk of interference with the impeller 200. By controlling the distance between the rear end 21 of the raised portion 20 and the first end 11 between 0.01L1 and 0.04L1, the risk of interference between the raised portion 20 and the impeller 200 can be reduced, thereby reducing the risk of interference between the movable guide vane 100 and the impeller 200 and improving the operational stability of the pump turbine 1000.

[0045] Reference Figure 1 In some embodiments, the length of the guide vane body 10 is L1, the raised portion 20 has a front end 22 away from the first end 11, and the distance between the front end 22 and the first end 11 along the length direction X of the movable guide vane 100 is L3, satisfying 0.08L1≤L3≤0.26L1.

[0046] For example, L3 can be 0.08L1, 0.1L1, 0.12L1, 0.15L1, 0.2L1, 0.22L1, 0.26L1, and any value between these.

[0047] In some embodiments, the length of the guide vane body 10 is L1, and the dimension of the raised portion 20 along the length direction X of the movable guide vane 100 is W, satisfying 0.07L1≤W≤0.22L1. By controlling the length of the raised portion 20 between 0.07L1 and 0.22L1, the raised portion 20 can reduce the pressure pulsation of the pump turbine 1000 under low load conditions, while also reducing the resistance caused by the raised portion 20 under ideal operating conditions, which helps the pump turbine 1000 to operate stably under both low and high load conditions.

[0048] It can be understood that the guide vane body 10 has a first end 11 close to the impeller 200 and a second end 12 far from the impeller 200, and the distance between the first end 11 and the second end 12 is the length of the guide vane body 10.

[0049] For example, W can be 0.07L1, 0.1L1, 0.12L1, 0.15L1, 0.17L1, 0.2L1, 0.22L1, and any value in between.

[0050] In some embodiments, the length of the guide vane body 10 is between 0.6m and 1.5m.

[0051] In some embodiments, along the length direction X of the movable guide vane 100, from the middle to both ends of the guide vane body 10, the thickness of the guide vane body 10 gradually decreases, and the position where the thickness of the guide vane body 10 is the largest is the guide vane throat 13, and the raised portion 20 is located between the guide vane throat 13 and the first end 11.

[0052] Typically, a flow-through component, such as a volute, is also provided on the outer side of the movable guide vane 100. This volute, together with the movable guide vane 100, serves to guide the water flow and optimize energy conversion. The volute, spiraling around the movable guide vane 100, is the first flow-through channel for water entering the unit. As the water flows from the inlet of the volute along the spiral path towards the center, the volute converts the pressure energy of the water flow into kinetic energy through its gradually contracting cross-section, and delivers it to the movable guide vane 100 area with a uniform circulation distribution. The movable guide vane 100, located inside the volute, directly receives the water flow exiting the volute and further controls the direction and flow rate of the water flow by adjusting its own angle. The water flow at the inlet of the movable guide vane 100 is constrained by the volute and flows centripetally, resulting in a relatively uniform velocity distribution and a flow direction that matches the curvature of the leading edge of the movable guide vane 100, leading to minimal energy loss. However, at the outlet, after the water flow leaves the constraint of the movable guide vane 100, if the opening of the movable guide vane 100 does not match the flow rate (e.g., closing the opening at low flow rates), the abrupt change in the contact area between the movable guide vane 100 and the water flow leads to an increased velocity gradient, exacerbating flow turbulence and making it more prone to inducing flow separation and eddies. Therefore, the induction of flow separation and eddies occurs near the outlet of the movable guide vane 100. Placing the raised portion 20 in the middle and rear section of the movable guide vane 100 can effectively prevent water flow from falling off under low load conditions and reduce pressure pulsation of the pump turbine 1000 under low load conditions. The middle and rear section refers to the section of the movable guide vane 100 near the impeller 200.

[0053] In this embodiment of the application, by setting the raised portion 20 between the first end 11 and the guide vane throat 13, the raised portion 20 is located in the middle and rear section of the guide vane body 10, which can reduce the pressure pulsation of the water pump turbine 1000 under low load conditions, and at the same time reduce the resistance caused by the raised portion 20 under ideal conditions.

[0054] In some embodiments, the raised portion 20 and the guide vane throat 13 are spaced apart along the length direction X of the movable guide vane 100. This arrangement can reduce the resistance of the raised portion 20 to the bladeless area under low load conditions, thereby reducing energy loss.

[0055] In some embodiments, the distance between the raised portion 20 and the guide vane throat 13 is L4, satisfying 0.24L1≤L4≤0.32L1. This arrangement provides a suitable distance between the raised portion 20 and the guide vane throat 13, balancing pressure pulsation and energy loss in the pump turbine 1000.

[0056] For example, L4 can be 0.24L1, 0.26L1, 0.28L1, 0.3L1, 0.32L1, and any value in between.

[0057] In some embodiments, the raised portion 20 does not extend beyond the guide vane throat 13 along the width direction Y of the movable guide vane 100. This configuration reduces the size of the raised portion 20 extending into the bladeless area, thereby reducing the resistance of the raised portion 20 to the water flow.

[0058] In some embodiments, the thickness of the raised portion 20 increases and then decreases from the first end 11 to the guide vane throat 13.

[0059] Reference Figure 1 and Figure 2 In some embodiments, the guide vane body 10 has a first surface 14 and a second surface 15 facing the impeller 200, and the raised portion 20 has a third surface 23 facing the impeller 200, the third surface 23 connecting the first surface 14 and the second surface 15.

[0060] The projection curve S1 of the first surface 14 in the thickness direction of the movable guide vane 100 satisfies Equation 1:

[0061]

[0062] The projection curve S2 of the third surface 23 in the thickness direction of the movable guide vane 100 satisfies Equation 2:

[0063]

[0064] The projection curve S3 of the second surface 15 in the thickness direction of the movable guide vane 100 satisfies Equation 3:

[0065]

[0066] In Equation 1, Here, is a coefficient used to determine the contribution weight of each control point to the curve; 'i' is the index for summation, used to iterate through each term in the formula; 'P' is the index for summation. iThese are the control points of the Bézier curve, and are coordinate points (X, Y, Z) in a two-dimensional plane. i Y i (i = 0, 1, 2, 3, a total of 4 control points, which determine the shape and direction of the Bézier curve. By changing the value of t, the points at different positions are calculated using Equation 1, thereby depicting the Bézier curve, which is the projection curve S1 of the first surface 14 in the thickness direction of the movable guide vane 100.)

[0067] The principle for obtaining curve S1 is as follows: For each value of t in the interval [0,1], a corresponding point is calculated using Equation 1. The curve starts at the first control point P0; when t = 1, B1(1) = P3, and the curve terminates at the last control point P3. As t gradually changes from 0 to 1, B1(t) is continuously calculated to obtain a series of points. Connecting these points sequentially forms a smooth third-order Bézier curve, which is curve S1.

[0068] In Equation 2, Q is a coefficient used to determine the contribution weight of each control point to the curve; j is the index for summation, used to iterate through each term in the formula. j These are the control points of the Bézier curve, and are coordinate points (X, Y, Z) in a two-dimensional plane. j Y j (j = 0, 1, 2, 3, 4, a total of 5 control points, which determine the shape and direction of the Bézier curve. By changing the value of t, the points at different positions are calculated by substituting into Equation 2, thereby depicting the Bézier curve, which is the projection curve S2 of the third surface 23 in the thickness direction of the movable guide vane 100.)

[0069] The principle for obtaining curve S2 is as follows: For each value of t in the interval [0,1], a corresponding point is calculated using Equation 2. The curve starts at the first control point Q0; when t = 1, B2(1) = Q3, and the curve terminates at the last control point Q4. As t gradually changes from 0 to 1, B2(t) is continuously calculated to obtain a series of points. Connecting these points sequentially forms a smooth fourth-order Bézier curve, which is curve S2.

[0070] In formula three, R is a coefficient used to determine the contribution weight of each control point to the curve; k is the index for summation, used to iterate through each term in the formula. k These are the control points of the Bézier curve, and are coordinate points (X, Y, Z) in a two-dimensional plane. k Y k(k = 0, 1, 2, 3, a total of 4 control points, the four control points determine the shape and direction of the Bézier curve. By changing the value of t, the points at different positions are calculated by substituting into Equation 3, thereby depicting the Bézier curve, which is the projection curve S3 of the second surface 15 in the thickness direction of the movable guide vane 100.)

[0071] The principle for obtaining curve S3: For each value of t in the interval [0,1], a corresponding point is obtained by calculating using Equation 3. The curve starts at the first control point R0; when t=1, B3(1)=R3, and the curve ends at the last control point R3. As t gradually changes from 0 to 1, B3(t) is continuously calculated to obtain a series of points. Connecting these points in sequence forms a smooth third-order Bézier curve, which is curve S3.

[0072] Examples include P0(0,0), P1(3,5), P2(17,8), P3(24,10); Q0(24,10), Q1(35,20), Q2(45,19), Q3(55,18); Q4(60,17); R0(60,17), R1(100,18), R2(150,16), R3(200,0).

[0073] Curves S1, S2 and S3 satisfy the Bezier formula, and the shape of the curves can be flexibly adjusted by control points to obtain the desired shape of the first surface 14, the third surface 23 and the second surface 15.

[0074] Figure 3 A schematic diagram of the structure of the water pump turbine 1000 provided for an embodiment of this application is shown below. Figure 3 This application provides a water pump turbine 1000, which includes an impeller 200 and the aforementioned movable guide vanes 100. The impeller 200 includes an upper crown, blades 220, and a lower ring 210. The upper end of the blades 220 is connected to the upper crown, and the lower end is connected to the lower ring 210. The lower ring 210 is an annular structure disposed at the bottom of the blades 220 of the impeller 200, which is used to connect the lower end of the blades 220 and enhance the structural strength.

[0075] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0076] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0077] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0078] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A movable vane, characterized in that, The application relates to a movable guide vane for controlling the water flow into an impeller, the movable guide vane comprising: a guide vane body having a first end close to the impeller; a protrusion provided on a side of the guide vane body facing the impeller, the protrusion being spaced apart from the first end along the length direction of the movable guide vane, and the protrusion being used for adjusting the flow state of water flowing into the impeller.

2. The movable vane according to claim 1, characterized in that The guide vane body and the protrusion are integrally formed.

3. The movable vane of claim 1, wherein, The length of the guide vane body is L1, the protrusion has a rear end close to the first end, the distance between the rear end and the first end along the length direction of the movable guide vane is L2, and 0.01L1<=L2<=0.04L1 is satisfied; and / or The protrusion has a front end away from the first end, the distance between the front end and the first end along the length direction of the movable guide vane is L3, and 0.08L1<=L3<=0.26L1 is satisfied.

4. The movable vane of claim 1, wherein, The length of the guide vane body is L1, and the size of the protrusion along the length direction of the movable guide vane is W, and 0.07L1<=W<=0.22L1 is satisfied.

5. The movable vane according to any one of claims 1 to 4, characterized in that Along the length direction of the movable guide vane, the thickness of the guide vane body gradually decreases from the middle to the two ends of the guide vane body, the position with the maximum thickness of the guide vane body is a guide vane throat, and the protrusion is located between the guide vane throat and the first end.

6. The movable vane of claim 5, wherein, Along the length direction of the movable guide vane, the protrusion is spaced apart from the guide vane throat.

7. The movable vane of claim 5, wherein, The distance between the protrusion and the guide vane throat is L4, and 0.24L1<=L4<=0.32L1 is satisfied.

8. The movable vane of claim 5, wherein, Along the width direction of the movable guide vane, the protrusion does not protrude out of the guide vane throat.

9. The movable vane according to any one of claims 1-5, characterized in that The guide vane body has a first surface and a second surface facing the impeller, the protrusion has a third surface facing the impeller, the third surface connects the first surface and the second surface, the projection curve S1 of the first surface in the thickness direction of the movable guide vane satisfies a Bezier formula one: The projection curve S2 of the third surface in the thickness direction of the movable guide vane satisfies a Bezier formula two: The projection curve S3 of the second surface in the thickness direction of the movable guide vane satisfies a Bezier formula three:

10. A pump turbine, characterized by The application further relates to a movable guide vane comprising the movable guide vane according to any one of claims 1-9.

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