Runner and Francis turbine

Abstract

The application discloses a runner and a mixed-flow water turbine. The runner comprises an upper crown, a lower ring, a plurality of first blades and a plurality of second blades, the plurality of first blades are connected between the upper crown and the lower ring, the plurality of first blades are distributed at intervals around an axis, the first blade comprises a first inlet edge and a first outlet edge, the first outlet edge is located on one side of the first inlet edge close to the axis, and the first blade has a first virtual flow line extending from the first inlet edge to the first outlet edge; the plurality of second blades are connected between the upper crown and the lower ring, the plurality of second blades are distributed at intervals around the axis, the second blade comprises a second inlet edge and a second outlet edge, the second outlet edge is located on one side of the second inlet edge close to the axis, and the second blade has a second virtual flow line extending from the second inlet edge to the second outlet edge, wherein the ratio of the length of the second virtual flow line to the length of the first virtual flow line is 0.66 to 0.8. The runner provided by the application has good working stability.

Description

Technical Field

[0001] This application belongs to the field of water turbine technology, and particularly relates to a runner and a mixed-flow water turbine. Background Technology

[0002] With the increasing awareness of environmental protection and energy conservation, society's demand for utilizing clean and renewable energy to achieve energy conservation, emission reduction, and environmental pollution reduction is also constantly increasing, making the hydropower industry highly sought after. Among them, a water turbine is a power machine that can convert the energy of water flow into rotational mechanical energy. When water flow is directed to the turbine's runner, the water flow can drive the runner to rotate, thereby driving the generator to generate electricity.

[0003] However, when the water flow contains silt or other impurities, these impurities can easily cause wear or impact on the turbine blades, making the turbine prone to damage, reducing its operational reliability and service life, and resulting in higher maintenance costs for the turbine. Summary of the Invention

[0004] This application provides a runner and a mixed-flow turbine, which aims to improve the operational reliability of the runner.

[0005] In a first aspect, embodiments of this application provide a runner for a mixed-flow turbine. The runner includes an upper crown, a lower ring, a plurality of first blades, and a plurality of second blades. The plurality of first blades are connected between the upper crown and the lower ring and are spaced apart around an axis. Each first blade includes a first inlet side and a first outlet side, with the first outlet side located on the side of the first inlet side closer to the axis. Each first blade has a first virtual streamline extending from the first inlet side to the first outlet side. The plurality of second blades are connected between the upper crown and the lower ring and are spaced apart around an axis. Each second blade includes a second inlet side and a second outlet side, with the second outlet side located on the side of the second inlet side closer to the axis. Each second blade has a second virtual streamline extending from the second inlet side to the second outlet side, wherein the ratio of the length of the second virtual streamline to the length of the first virtual streamline is 0.66 to 0.8.

[0006] According to an embodiment of the first aspect of this application, the distance between the first inlet edge and the axis is equal to the distance between the second inlet edge and the axis.

[0007] According to any of the foregoing embodiments of the first aspect of this application, the first blade further includes a first surface and a second surface connected between the first inlet edge and the first outlet edge, and the distance between the first virtual streamline and the first surface is equal to the distance between the first virtual streamline and the second surface; the second blade further includes a third surface and a fourth surface connected between the second inlet edge and the second outlet edge, and the distance between the second virtual streamline and the third surface is equal to the distance between the second virtual streamline and the fourth surface.

[0008] According to any of the foregoing embodiments of the first aspect of this application, the first blade further includes a first upper surface and a first lower surface connected between the first surface and the second surface, the first upper surface being connected to an upper crown, the first lower surface being connected to a lower ring, and a first reference point and a second reference point on the extension path of the first virtual streamline, a first ratio being formed between the distance from the first reference point to the first upper surface and the distance from the first reference point to the first lower surface, and a second ratio being formed between the distance from the second reference point to the first upper surface and the distance from the second reference point to the first lower surface, the first ratio and the second ratio being equal; and / or, the second blade further includes a second upper surface and a second lower surface connected between the third surface and the fourth surface, the second upper surface being connected to an upper crown, the second lower surface being connected to a lower ring, and a third reference point and a fourth reference point on the extension path of the second virtual streamline, a third ratio being formed between the distance from the third reference point to the second upper surface and the distance from the third reference point to the second lower surface, and a fourth ratio being formed between the distance from the fourth reference point to the second upper surface and the distance from the fourth reference point to the second lower surface, the third ratio and the fourth ratio being equal.

[0009] According to any of the foregoing embodiments of the first aspect of this application, in the direction from the upper crown to the lower ring, the first blade and the second blade each have n first virtual streamlines and n second virtual streamlines, wherein the ratio between the length of the i-th second virtual streamline and the length of the i-th first virtual streamline at the same height in the axial direction is 0.66 to 0.8.

[0010] According to any of the foregoing embodiments of the first aspect of this application, the ratio between the length of the second virtual streamline and the length of the first virtual streamline is 0.8.

[0011] According to any of the foregoing embodiments of the first aspect of this application, the number of first blades is 7 and the number of second blades is 7.

[0012] According to any of the foregoing embodiments of the first aspect of this application, the wrap angle of the first blade is 38° to 49.7°; and / or, the placement angle of the first blade is 15° to 20°.

[0013] According to any of the foregoing embodiments of the first aspect of this application, the first blade and the second blade are alternately distributed in the circumferential direction.

[0014] Secondly, embodiments of this application provide a mixed-flow turbine, which includes the runner as described in any of the embodiments of the first aspect above.

[0015] An embodiment of this application provides a rotor comprising an upper crown, a lower ring, a plurality of first blades, and a plurality of second blades. The plurality of first blades are spaced apart around an axis, and the plurality of second blades are spaced apart around an axis. Water can flow into the gaps between the first blades and the second blades from the first inlet side and the second inlet side, and act on the surfaces of the first blades and the second blades to drive the rotor to rotate, and then flow out of the rotor from the first outlet side and the second outlet side. The first blade has a first virtual streamline extending from the first inlet side to the first outlet side, and the second blade has a second virtual streamline extending from the second inlet side to the second outlet side. By setting the ratio of the length of the second virtual streamline to the length of the first virtual streamline to be 0.66 to 0.8, the extension dimension of the first blade in the direction from the first inlet side to the first outlet side is greater than the extension dimension of the second blade in the direction from the second inlet side to the second outlet side. This allows the water flow to have a better vortex structure within the impeller, improving the impeller's working efficiency and operational stability. Furthermore, because the ratio of the length of the second virtual streamline to the length of the first virtual streamline is 0.66 to 0.8, the water flow will not have an excessively high relative velocity to the impeller during operation, making it less likely for severe wear and impact to occur between the water flow and the impeller, thereby improving the impeller's operational reliability and service life. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in 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.

[0017] Figure 1 This is a schematic diagram of the structure of the rotary wheel in some embodiments of this application;

[0018] Figure 2 This is a schematic diagram of the structure of the first blade in some embodiments of this application;

[0019] Figure 3 This is a top view of the rotor structure after the upper crown is removed, according to some embodiments of this application;

[0020] Figure 4 This is a side view of the rotating wheel according to some embodiments of this application;

[0021] Figure 5 This is a schematic diagram of the structure of the first blade in some other embodiments of this application;

[0022] Figure 6 This is a schematic diagram of the structure of the second blade in some embodiments of this application.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1-Rotating wheel;

[0025] 11-top crown;

[0026] 12-Lower ring; 121-Opening;

[0027] 13-First blade; 13a-First virtual streamline; 13b-First profile line; 13c-First reference point; 13d-Second reference point; 131-First inlet edge; 132-First outlet edge; 133-First surface; 134-Second surface; 135-First upper surface; 136-First lower surface;

[0028] 14-Second blade; 14a-Second virtual streamline; 14b-Second profile line; 14c-Third reference point; 14d-Fourth reference point; 141-Second inlet edge; 142-Second outlet edge; 143-Third surface; 144-Fourth surface; 145-Second upper surface; 146-Second lower surface;

[0029] a-axis;

[0030] X-axis;

[0031] R-Zhou Xiang. Detailed Implementation

[0032] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are intended only to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples. In the drawings and the following description, at least some well-known structures and technologies are not shown in order to avoid causing unnecessary ambiguity to this application; and, for clarity, the dimensions of some structures may be exaggerated. Furthermore, the features, structures, or characteristics described below can be combined in any suitable manner in one or more embodiments.

[0033] It should be noted that, unless otherwise stated, "a plurality of" in this document means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, 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. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus 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 apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0034] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the embodiments of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] With the increasing awareness of environmental protection and energy conservation, society's demand for utilizing clean and renewable energy to achieve energy conservation, emission reduction, and environmental pollution reduction is also constantly increasing, making the hydropower industry highly sought after. A water turbine is a power machine that converts the energy of flowing water into rotational mechanical energy. When water is drawn to the turbine's runner, the water flow drives the runner to rotate, thereby driving a generator to produce electricity. However, when the water flow contains silt or other impurities, these impurities can easily cause wear or impact on the runner's blades, making the runner prone to damage, reducing its operational reliability and service life, and resulting in higher maintenance costs for the water turbine.

[0036] To address the aforementioned technical problems, this application is provided. To better understand this application, the runner and mixed-flow turbine of the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the structure of the rotor 1 in some embodiments of this application. Figure 2This is a schematic diagram of the structure of the first blade 13 in some embodiments of this application. Figure 3 This is a top view of the rotor 1 after removing the upper crown 11 in some embodiments of this application. Figure 4 This is a side view of the rotating wheel 1 according to some embodiments of this application. Figure 5 This is a schematic diagram of the structure of the first blade 13 in some other embodiments of this application. Figure 6 This is a schematic diagram of the structure of the second blade 14 in some embodiments of this application. In the figure, the X direction is the axial direction, that is, the extension direction of the axis a, and the R direction is the circumferential direction. Figure 5 The first contour line 13b located on the first surface 133 is a dashed line. Figure 5 The first contour line 13b located on the second surface 134 is a solid line. Figure 6 The second contour line 14b located on the third surface 143 is a dashed line. Figure 6 The second contour line 14b located on the fourth surface 144 is a solid line.

[0038] like Figures 1 to 6 As shown in the figure, this application embodiment provides a runner 1 for a mixed-flow turbine. The runner 1 includes an upper crown 11, a lower ring 12, a plurality of first blades 13, and a plurality of second blades 14. The plurality of first blades 13 are connected between the upper crown 11 and the lower ring 12 and are distributed at intervals around an axis a. Each first blade 13 includes a first inlet edge 131 and a first outlet edge 132. The first outlet edge 132 is located on the side of the first inlet edge 131 closer to the axis a. The first blade 13 extends from the first inlet edge 131 to the first outlet edge 132. The first virtual streamline 13a; a plurality of second blades 14 are connected between the upper crown 11 and the lower ring 12, and the plurality of second blades 14 are distributed at intervals around the axis a. The second blades 14 include a second inlet edge 141 and a second outlet edge 142. The second outlet edge 142 is located on the side of the second inlet edge 141 closer to the axis a. The second blades 14 have a second virtual streamline 14a extending from the second inlet edge 141 to the second outlet edge 142, wherein the ratio of the length of the second virtual streamline 14a to the length of the first virtual streamline 13a is 0.66 to 0.8.

[0039] An impeller 1 provided in this application embodiment includes an upper crown 11, a lower ring 12, a plurality of first blades 13, and a plurality of second blades 14. The plurality of first blades 13 are spaced apart around axis a, and the plurality of second blades 14 are spaced apart around axis a. Water can flow into the gaps between each first blade 13 and each second blade 14 from the first inlet side 131 and the second inlet side 141, and act on the surfaces of the first blades 13 and the second blades 14 to drive the rotation of the impeller 1, and then flow out of the impeller 1 from the first outlet side 132 and the second outlet side 142. The first blade 13 has a first virtual streamline 13a extending from the first inlet side 131 to the first outlet side 132, and the second blade 14 has a second virtual streamline 14a extending from the second inlet side 141 to the second outlet side 142. By setting the ratio of the length of the second virtual streamline 14a to the length of the first virtual streamline 13a to 0.66 to 0.8, the extension dimension of the first blade 13 in the direction from the first inlet side 131 to the first outlet side 132 is greater than the extension dimension of the second blade 14 in the direction from the second inlet side 141 to the second outlet side 142. This allows the water flow to have a better flow field vortex structure within the impeller 1, improving the working efficiency and operational stability of the impeller 1. Furthermore, since the ratio of the length of the second virtual streamline 14a to the length of the first virtual streamline 13a is 0.66 to 0.8, the water flow will not have an excessively large relative velocity to the impeller 1 during operation, making it less likely for severe wear and impact to occur between the water flow and the impeller 1, thereby improving the working reliability and service life of the impeller 1.

[0040] In some embodiments, the connection between the first blade 13 and the upper crown 11 and the lower ring 12 can be in various ways, and the connection between the second blade 14 and the upper crown 11 and the lower ring 12 can also be in various ways. For example, the first blade 13 can be connected to the upper crown 11 and the lower ring 12 by welding, and the second blade 14 can also be connected to the upper crown 11 and the lower ring 12 by welding.

[0041] like Figure 1 As shown, in some embodiments, the lower ring 12 has an opening 121 that extends through along the axial direction X. The first blade 13 and the second blade 14 are connected between the inner wall of the lower ring 12 facing the opening 121 and the upper crown 11. Water flowing out from the first outlet side 132 and the second outlet side 142 can flow out of the impeller 1 through the opening 121.

[0042] In some embodiments, the first blade 13 and the second blade 14 can be X-shaped blades, such as... Figure 2As shown, in the direction from the first inlet side 131 to the first outlet side 132, the projection of the first inlet side 131 intersects with the projection of the first outlet side 132, forming an X-shape. Similarly, in the direction from the second inlet side 141 to the second outlet side 142, the projection of the second inlet side 141 intersects with the projection of the second outlet side 142, forming an X-shape. The X-shaped blade arrangement allows for a more uniform pressure distribution on the first blade 13 and the second blade 14 when the impeller 1 is operating, resulting in a more rational flow pattern of water flowing out from the first outlet side 132 and the second outlet side 142.

[0043] like Figure 3 As shown, in some embodiments, the first blade 13 and the second blade 14 are alternately distributed along the circumferential direction R, so that the arrangement of the first blade 13 and the second blade 14 in the impeller 1 is relatively uniform, and the water flowing in the impeller 1 has a better flow pattern.

[0044] like Figure 3 As shown, in some embodiments, the number of first blades 13 is 7 and the number of second blades 14 is 7. By reasonably setting the number of first blades 13 and second blades 14, a suitable space size is provided between the first blades 13 and second blades 14 to facilitate the passage of water flow, thereby allowing the water flow to be smooth in the impeller 1 and preventing the water flow from having an excessively large relative velocity with respect to the impeller 1.

[0045] like Figure 4 As shown, in some embodiments, the distance between the first inlet edge 131 and the axis a can be equal to the distance between the second inlet edge 141 and the axis a. Since the extension dimension of the first blade 13 in the direction from the first inlet edge 131 to the first outlet edge 132 is greater than the extension dimension of the second blade 14 in the direction from the second inlet edge 141 to the second outlet edge 142, the distance between the first outlet edge 132 and the axis a is smaller than the distance between the second outlet edge 142 and the axis a. This allows the water flow to be smoother in the impeller 1. In particular, when the water flow reaches the vicinity of the lower ring 12 in the impeller 1, the water flow will not have a large relative velocity with respect to the impeller 1. This makes it less likely for the water flow to experience severe wear and impact with the impeller 1 at the lower ring 12, thereby improving the working reliability and service life of the impeller 1.

[0046] In some embodiments, the distance between the first inlet edge 131 and the axis a is equal to the distance between the second inlet edge 141 and the axis a. This can mean that a point on the first inlet edge 131 and a point on the second inlet edge 141 at the same height in the axial direction X have the same distance from the axis a. Similarly, in some embodiments, the distance between the first outlet edge 132 and the axis a is less than the distance between the second outlet edge 142 and the axis a. This can mean that the distance between any point on the first outlet edge 132 and the axis a is less than the distance between a point on the second outlet edge 142 at the same height and the axis a.

[0047] The distance between a point and a straight line or between a point and a curve described in some embodiments of this application may refer to the minimum distance between a point and a straight line or between a point and a curve.

[0048] The height of a point in the axial direction X described in some embodiments of this application can refer to the relative distance of the point to any reference plane in the direction perpendicular to the axis a. This relative distance can be positive or negative. When a point is located on one side of the reference plane and the relative distance (i.e., height) between the point and the reference plane is positive, then the relative distance (i.e., height) between other points located on the other side of the reference plane and the reference plane is negative. For example, the reference plane can be the upper surface of the lower ring 12 near the upper crown 11. The heights of the points on the first inlet edge 131 and the second inlet edge 141 located on the upper surface of the lower ring 12 near the upper crown 11 can both be positive, and the heights of the points on the first inlet edge 131 and the second inlet edge 141 located on the upper surface of the lower ring 12 away from the upper crown 11 can both be negative.

[0049] In some embodiments, the first blade 13 further includes a first surface 133 and a second surface 134 connected between the first inlet edge 131 and the first outlet edge 132, and the second blade 14 further includes a third surface 143 and a fourth surface 144 connected between the second inlet edge 141 and the second outlet edge 142. In some embodiments, the first virtual streamline 13a may be located on the first surface 133 or the second surface 134 of the first blade 13, and the second virtual streamline 14a may be located on the third surface 143 or the fourth surface 144 of the second blade 14.

[0050] In other embodiments, such as Figure 5 As shown, the first virtual streamline 13a can be located in the central portion between the first surface 133 and the second surface 134 of the first blade 13. For example, the first virtual streamline 13a can be located between two adjacent first profile lines 13b of the same height along the axial direction X on the first surface 133 and the second surface 134. Figure 6As shown, the second virtual streamline 14a can be located in the central portion between the third surface 143 and the fourth surface 144 of the second blade 14. For example, the second virtual streamline 14a can be located on the third surface 143 and the fourth surface 144 between two adjacent second profile lines 14b with the same height along the axial direction X.

[0051] In this embodiment, the distance between the first virtual streamline 13a and the first surface 133 can be equal to the distance between the first virtual streamline 13a and the second surface 134, and the distance between the second virtual streamline 14a and the third surface 143 can be equal to the distance between the second virtual streamline 14a and the fourth surface 144. This allows the second blade 14 to be processed based on the first blade 13. For example, the first blade 13 can be cut to obtain a second blade 14 in a semi-finished state with the second virtual streamline 14a. At this time, the second blade 14 in the semi-finished state has a third initial surface and a fourth initial surface connecting the second inlet edge 141 and the second outlet edge 142. In order to make the finished second blade 14 have a smaller thickness and a better transition shape near the second outlet edge 142, it is necessary to further process the third initial surface and the fourth initial surface of the semi-finished second blade 14 to adjust the thickness and obtain the finished second blade 14 with the third surface 143 and the fourth surface 144.

[0052] Therefore, when the first virtual streamline 13a is located in the central portion between the first surface 133 and the second surface 134 of the first blade 13, and the second virtual streamline 14a is located in the central portion between the third surface 143 and the fourth surface 144 of the second blade 14, the length of the second virtual streamline 14a is not easily changed when processing the third and fourth initial surfaces, allowing for better control of the length of the second virtual streamline 14a when cutting the first blade 13. However, when the first virtual streamline 13a is located on either the first surface 133 or the second surface 134 of the first blade 13, and the second virtual streamline 14a is located on either the third surface 143 or the fourth surface 144 of the second blade 14, processing the surface of the second blade 14 in a semi-finished state will change the length of the second virtual streamline 14a, making it difficult to achieve the same level of control as when processing the surface of the second blade 14 in a finished state.

[0053] In some embodiments, when designing the thickness of the first blade 13 under a certain operating condition, the thickness of the first blade 13 can be uniformly increased by 15% to 20% compared to the thickness of a conventional blade under that operating condition, so that when the second blade 14 is formed on the basis of the first blade 13, the thickness of the second blade 14 can be thinned and transitioned, and the second blade 14 will not be too thin.

[0054] In some embodiments, the distance between the first virtual streamline 13a and the first surface 133 is equal to the distance between the first virtual streamline 13a and the second surface 134. This can mean that the distance between any point on the first virtual streamline 13a and the first surface 133 is equal to the distance between that point and the second surface 134. Similarly, the distance between the second virtual streamline 14a and the third surface 143 is equal to the distance between the second virtual streamline 14a and the fourth surface 144. This can mean that the distance between any point on the second virtual streamline 14a and the third surface 143 is equal to the distance between that point and the fourth surface 144. Furthermore, the distance between a point and a surface described in some embodiments of this application can refer to the minimum distance between a point and a surface.

[0055] In some embodiments, such as Figure 5 As shown, the first blade 13 also includes a first upper surface 135 and a first lower surface 136 connected between the first surface 133 and the second surface 134. The first upper surface 135 is connected to the upper crown 11, and the first lower surface 136 is connected to the lower ring 12. The extension path of the first virtual streamline 13a has a first reference point 13c and a second reference point 13d. The distance from the first reference point 13c to the first upper surface 135 (e.g., Figure 5 The distance between L1 and the first reference point 13c to the first lower surface 136 (e.g., Figure 5 The first ratio exists between L2 and L3, and the distance from the second reference point 13d to the first upper surface 135 is (e.g., ...). Figure 5 The distance from L3 to the second reference point 13d to the first lower surface 136 (e.g., Figure 5 There is a second ratio between L4 and L4, and the first and second ratios are equal; and / or, as Figure 6 As shown, the second blade 14 also includes a second upper surface 145 and a second lower surface 146 connected between the third surface 143 and the fourth surface 144. The second upper surface 145 is connected to the upper crown 11, and the second lower surface 146 is connected to the lower ring 12. The extension path of the second virtual streamline 14a has a third reference point 14c and a fourth reference point 14d. The distance from the third reference point 14c to the second upper surface 145 (e.g., Figure 6 The distance from L5 (middle) to the third reference point 14c to the second lower surface 146 (e.g., Figure 6 There is a third ratio between L6 and the fourth reference point 14d, and the distance from the fourth reference point 14d to the second upper surface 145 (e.g., Figure 6 The distance from L7 (middle) to the fourth reference point 14d to the second lower surface 146 (e.g., Figure 6 There is a fourth ratio between L8 and L8, and the third and fourth ratios are equal.

[0056] In some embodiments, the first reference point 13c can be any point on the first virtual streamline 13a, and the second reference point 13d can be any point on the first virtual streamline 13a other than the first reference point 13c. For example, when both the first ratio and the second ratio are 1, the distance between any point on the first virtual streamline 13a and the first upper surface 135 is equal to the distance between that point and the first lower surface 136. As another example, when both the first ratio and the second ratio are 2, the distance between any point on the first virtual streamline 13a and the first upper surface 135 is equal to twice the distance between that point and the first lower surface 136.

[0057] In some embodiments, the third reference point 14c can be any point on the second virtual streamline 14a, and the fourth reference point 14d can be any point on the second virtual streamline 14a other than the third reference point 14c. For example, when both the third and fourth ratios are 1, the distance between any point on the second virtual streamline 14a and the second upper surface 145 is equal to the distance between that point and the second lower surface 146. As another example, when both the third and fourth ratios are 2, the distance between any point on the second virtual streamline 14a and the second upper surface 145 is equal to twice the distance between that point and the second lower surface 146.

[0058] By setting the first ratio and the second ratio to be equal, the direction of the first virtual streamline 13a can better represent and reflect the shape of the first blade 13. By setting the third ratio and the fourth ratio to be equal, the direction of the second virtual streamline 14a can also better represent and reflect the shape of the second blade 14. As a result, the extension dimension of the first blade 13 in the direction from the first inlet edge 131 to the first outlet edge 132 can be more uniformly greater than the extension dimension of the second blade 14 in the direction from the second inlet edge 141 to the second outlet edge 142.

[0059] like Figure 5 and Figure 6 As shown, in some embodiments, in the direction from the upper crown 11 to the lower ring 12, the first blade 13 and the second blade 14 have n first virtual streamlines 13a and n second virtual streamlines 14a, respectively, wherein the ratio between the length of the i-th second virtual streamline 14a and the length of the i-th first virtual streamline 13a at the same height in the axial direction X is 0.66 to 0.8.

[0060] This application does not limit the specific number of the first virtual streamline 13a and the second virtual streamline 14a, but the number of the first virtual streamline 13a must be equal to the number of the second virtual streamline 14a, so that any first virtual streamline 13a can have a corresponding second virtual streamline 14a at the same height in the axial direction X for comparison, or so that any second virtual streamline 14a can have a corresponding first virtual streamline 13a at the same height in the axial direction X for comparison.

[0061] In some embodiments, such as Figure 5 and Figure 6 As shown, the number of first virtual streamlines 13a and second virtual streamlines 14a can be greater than or equal to five. The more first virtual streamlines 13a and second virtual streamlines 14a are provided, the more the first virtual streamline 13a can represent the extension shape of the first blade 13 in the direction from the first inlet edge 131 to the first outlet edge 132. Similarly, the second virtual streamline 14a can also further represent the extension shape of the second blade 14 in the direction from the second inlet edge 141 to the second outlet edge 142. This ensures that when the ratio between the length of the i-th second virtual streamline 14a and the length of the i-th first virtual streamline 13a at the same height in the axial direction X is 0.66 to 0.8, the water flow is less likely to have a relative velocity exceeding 30.8 m / s relative to the impeller 1, making it less prone to severe wear and impact between the water flow and the impeller 1. Furthermore, this also results in a smaller pressure difference between the first inlet side 131 and the first outlet side 132, as well as a smaller pressure difference between the second inlet side 141 and the second outlet side 142. The minimum pressure inside the rotor 1 is larger, making it less prone to cavitation during rotor 1 operation, thereby improving the working reliability and service life of rotor 1.

[0062] In some embodiments, the i-th first virtual streamline 13a and the i-th second virtual streamline 14a being at the same height in the axial direction X can refer to the intersection of the i-th first virtual streamline 13a and the first inlet edge 131 and the intersection of the i-th second virtual streamline 14a and the second inlet edge 141 being at the same height in the axial direction X.

[0063] In some embodiments, the first ratio, second ratio, third ratio, and fourth ratio of the i-th first virtual streamline 13a and the i-th second virtual streamline 14a at the same height in the axial direction X are all equal, so that there is a good correlation between the shape and size of the first blade 13 and the shape and size of the second blade 14. When processing the first blade 13 and the second blade 14, it is easy to control the ratio between the length of the i-th second virtual streamline 14a and the length of the i-th first virtual streamline 13a at the same height in the axial direction X to be 0.66 to 0.8.

[0064] In some embodiments, the wrap angle of the first blade 13 is 38° to 49.7°; and / or, the placement angle of the first blade 13 is 15° to 20°. By reasonably setting the wrap angle and placement angle of the first blade 13, when the water flows in the impeller 1 to the vicinity of the lower ring 12, the water flow will not have a large relative velocity with respect to the impeller 1. This makes it less likely for severe wear and impact to occur between the water flow and the impeller 1 at the lower ring 12, and also improves the hydraulic performance of the impeller 1. This also makes cavitation less likely to occur, and allows the impeller 1 to operate more smoothly.

[0065] In some embodiments, the ratio of the length of the second virtual streamline 14a to the length of the first virtual streamline 13a is 0.8. By setting the ratio of the length of the second virtual streamline 14a to the length of the first virtual streamline 13a to 0.8, the impeller 1 can have better overall performance. This ensures that the relative flow velocity of the water flow to the impeller 1 does not easily exceed 30.8 m / s, reducing the likelihood of severe wear and impact between the water flow and the impeller 1. It also results in a smaller pressure difference between the first inlet edge 131 and the first outlet edge 132, and a smaller pressure difference between the second inlet edge 141 and the second outlet edge 142. The minimum pressure inside the impeller 1 can be greater than -1*10. 5 Pa makes cavitation less likely to occur during the operation of the rotor 1, thereby improving the working reliability and service life of the rotor 1. While improving the working reliability of the rotor 1, when the ratio between the length of the second virtual streamline 14a and the length of the first virtual streamline 13a is 0.8, the rotor 1 can still have a large and relatively stable power, and the rotor 1 can still maintain high efficiency when operating outside the design conditions, so that the rotor 1 can operate stably.

[0066] According to some embodiments of this application, this application also provides a mixed-flow turbine, which includes a runner 1 as described in any of the foregoing embodiments. This mixed-flow turbine can have good operational reliability.

[0067] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A runner for a mixed-flow turbine, characterized in that, include: top crown; Lower ring; Multiple first blades are connected between the upper crown and the lower ring. The multiple first blades are distributed at intervals around the axis. Each first blade includes a first inlet edge and a first outlet edge. The first outlet edge is located on the side of the first inlet edge closer to the axis. Each first blade has a first virtual streamline extending from the first inlet edge to the first outlet edge. Each first blade also includes a first surface and a second surface connected between the first inlet edge and the first outlet edge. The distance between the first virtual streamline and the first surface is equal to the distance between the first virtual streamline and the second surface. The wrap angle of the first blade is 38° to 49.7°. A plurality of second blades are connected between the upper crown and the lower ring, and are spaced apart around the axis. Each second blade includes a second inlet side and a second outlet side, with the second outlet side located on the side of the second inlet side closer to the axis. Each second blade has a second virtual streamline extending from the second inlet side to the second outlet side. The second blade also includes a third surface and a fourth surface connected between the second inlet side and the second outlet side, with the distance between the second virtual streamline and the third surface equal to the distance between the second virtual streamline and the fourth surface. The first and second blades are X-shaped blades, the ratio of the length of the second virtual streamline to the length of the first virtual streamline is 0.8, and the maximum thickness of the first blade is greater than the maximum thickness of the second blade. The first blade further includes a first upper surface and a first lower surface connected between the first surface and the second surface. The first upper surface is connected to the upper crown, and the first lower surface is connected to the lower ring. The extension path of the first virtual streamline has a first reference point and a second reference point. There is a first ratio between the distance from the first reference point to the first upper surface and the distance from the first reference point to the first lower surface, and a second ratio between the distance from the second reference point to the first upper surface and the distance from the second reference point to the first lower surface. The first ratio and the second ratio are equal. The second blade further includes a second upper surface and a second lower surface connected between the third surface and the fourth surface. The second upper surface is connected to the upper crown, and the second lower surface is connected to the lower ring. The extension path of the second virtual streamline has a third reference point and a fourth reference point. There is a third ratio between the distance from the third reference point to the second upper surface and the distance from the third reference point to the second lower surface, and there is a fourth ratio between the distance from the fourth reference point to the second upper surface and the distance from the fourth reference point to the second lower surface. The third ratio and the fourth ratio are equal.

2. The rotary wheel according to claim 1, characterized in that, The distance between the first inlet edge and the axis is equal to the distance between the second inlet edge and the axis.

3. The impeller according to claim 1, characterized in that, In the direction from the upper crown to the lower ring, the first blade and the second blade each have n first virtual streamlines and n second virtual streamlines, wherein the ratio of the length of the i-th second virtual streamline to the length of the i-th first virtual streamline at the same axial height is 0.66 to 0.

8.

4. The impeller according to any one of claims 1 to 3, characterized in that, The number of the first leaflets is 7, and the number of the second leaflets is 7.

5. The impeller according to any one of claims 1 to 3, characterized in that, The placement angle of the first blade is 15° to 20°.

6. The impeller according to any one of claims 1 to 3, characterized in that, The first blade and the second blade are alternately distributed circumferentially.

7. A mixed-flow turbine, characterized in that, Includes the impeller as described in any one of claims 1-6.

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