Automatic vortex control design method for box culvert type two-way water inlet flow channel

Abstract

The invention discloses an automatic vortex control design method for a box culvert type two-way water inlet flow channel in the field of water conservancy projects. The method comprises the following steps that S1, parameters of an impeller are determined; s2, determining the size of a water inlet runner; s3, designing a connection section; and S4, integration of the water inlet flow channel. According to the method, a brand-new connection mode is constructed by introducing a parameterized collaborative optimization design method and combining the combination of straight lines, conic curves and arcs. According to the method, water flow can be kept in a uniform and smooth flow state before entering the impeller inlet, the possibility that vortexes appear at the impeller inlet can be reduced, the cavitation risk is reduced, and therefore the efficiency of the water inlet runner is improved. Meanwhile, the modular design system enables the design, installation and implementation of the water inlet flow channel to be more convenient and efficient.

Description

Technical Field

[0001] The present invention belongs to the field of water conservancy projects, and particularly relates to an automatic vortex control design method for a box culvert type two-way intake channel. Background Art

[0002] At present, the connection design between the intake channel of a water pump and the impeller inlet is relatively simple and rough. Most of them are drawn by multi-segment fitting lines in CAD. The common problem of this connection method is that the connection part is not smooth enough, and turbulence is likely to occur at the connection of multi-segment lines, which exacerbates the cavitation risk at the impeller inlet. At the same time, due to the lack of a standardized mathematical definition for the fitting line, the construction difficulty is relatively large, relying on construction experience and having a high error rate. With the continuous improvement of the requirements for the performance of water pumps in industrial production and daily life, reducing the hydraulic loss between the intake channel and the impeller inlet, optimizing the connection method, and making the flow state of the water flow better in the connection section to improve the efficiency of the water pump have become important research directions.

[0003] Cavitation is one of the common problems in the operation of water pumps. It will cause the performance of the water pump to decline, generate vibration and noise, and even damage components such as the impeller. When the connection between the intake channel and the impeller inlet is poor, the water flow is prone to unstable flows such as vortices and turbulence, resulting in a local pressure reduction. When the pressure is lower than the saturated vapor pressure of water, cavitation will be triggered. Therefore, in order to avoid the occurrence of cavitation, it is necessary to improve the connection method so that the water flow can smoothly enter the impeller inlet. Summary of the Invention

[0004] The present invention mainly aims at the design problem of the connection section between the intake channel and the impeller inlet, and proposes a process-based design process. In traditional designs, the connection section is usually designed using multi-segment fitting lines, which have problems such as fuzzy parameters, complex construction, and uneven flow states. The present invention constructs a new connection method by introducing a parametric collaborative optimization design method and combining straight lines, conic curves, and arcs. This method can not only make the water flow maintain a uniform and smooth flow state before entering the impeller inlet, but also reduce the possibility of vortices appearing at the impeller inlet, reduce the cavitation risk, and thus improve the efficiency of the intake channel. At the same time, the modular design system of the present invention makes the design, installation, and implementation of the intake channel more convenient and efficient.

[0005] The purpose of the present invention is achieved as follows: An automatic vortex control design method for a box culvert type two-way intake channel includes the following steps:

[0006] S1. Determination of impeller parameters;

[0007] S2. Determination of the dimensions of the intake channel;

[0008] S3. Design of the connection section;

[0009] S4. Integration of the intake channel.

[0010] As a further improvement of the present invention, the determination of the impeller parameters in step S1 includes the following formula:

[0011] (1) Limit nD to the range of 350 to 425, where n is the rated speed of the pump and D is the impeller diameter;

[0012] (2) Pump similarity law formula n s is the specific speed of the water pump, Q is the flow rate, and H is the head;

[0013] (3) Dynamically adjust the hub range according to the pump operating conditions:

[0014]

[0015] In the formula, D1 is the hub diameter, k is the working condition correction coefficient, k = 2 ~ 5;

[0016] (4) Empirical formula for specific speed and impeller hub ratio in water pumps: is the impeller hub ratio;

[0017] Combining the above formulas (1)-(4) we can get the impeller diameter D, the pump rated speed n and the hub ratio This technical solution can optimize the hub diameter according to actual working conditions, break through the limitations of traditional hub ratio, improve design flexibility, and achieve coordinated matching of speed and impeller size.

[0018] As a further improvement of the present invention, the impeller inlet height h1 in the impeller parameter is limited to be 0.2-0.3D.

[0019] As a further improvement of the present invention, the determination of the size of the water inlet flow channel in step S2 includes the following sub-steps:

[0020] (a) Determination of the length L, width B and height H2 of the water inlet channel:

[0021] The length of the water inlet channel is L = 10 ~ 13D, the width of the water inlet channel is B = 3.0 ~ 4.0D, the center height of the impeller is H1 = 1.1 ~ 1.4D, and the height of the water inlet channel is H2 = 1.4 ~ 1.6D;

[0022] (b) Determination of design dimensions of water guide cone:

[0023] The outer arc shape of the water guide cone is designed to be Ellipse, water cone height h2 = 0.9 ~ 1.1D, the sum of the water cone height h2 and the impeller inlet height h1 is the impeller center height H1, h2 + h1 = H1;

[0024] The hub diameter D1 minus 0.1D equals the upper width of the water guide cone L2, L2 = D1-0.1D;

[0025] The lower width of the water guide cone is the same as the diameter of the trumpet pipe. The diameter of the trumpet pipe D2 = 1.4 - 1.7D. The major semi-axis a1 of the ellipse of the outer contour line of the water guide cone is h2, and the minor semi-axis of the ellipse of the outer contour line of the water guide cone The impeller center height is the most important parameter in the runner design. The larger this height is, the better the flow pattern at the pump inlet, but the more investment in the pump station civil engineering will be. Therefore, considering both the inlet flow pattern and the civil engineering investment, the impeller center height H1 = 1.1 - 1.4D is determined.

[0026] As a further improvement of the present invention, the connection section designed in the step S3 includes a straight section, an arc and ellipse O. The connection section is composed of two symmetric parts on the left and right. Each part includes a straight section, an arc and ellipse O. The connection of each section in the design of the connection part of the inlet runner is smooth. The parameter design of this technical solution is clear and very convenient for construction.

[0027] As a further improvement of the present invention, the parametric geometric modeling of the connection section is as follows:

[0028] Taking the center line of the bottom plate of the inlet runner as the X-axis and the impeller rotation axis as the Y-axis to establish a plane rectangular coordinate system,

[0029] The first part of the connection section is a straight section, starting at a distance of L1 / 2 from the Y-axis, where L1 is the total length of the connection section. The inclination angle of the straight line is α. The equation of the first part of the straight line section is: y = kx + b, where k = tanα, and the first part of the straight line section passes through the point α = 50° + 20°·log 10 (H2 / D), 45° ≤ α ≤ 75°;

[0030] The second part of the connection section is an arc with the center O1. The central angle of the arc is also α. The distance between the lowest point of the arc and the bottom plate of the inlet runner is the trumpet pipe suspension height C. The starting point of the second part of the arc is The trumpet pipe suspension height C = 0.5 - 0.75D, and the length of the arc radius R is:

[0031]

[0032] The second part of the arc should be represented in the plane rectangular coordinate system as an arc with as the center, radius R, and starting point rotating counterclockwise by α;

[0033] The third part of the connection section is ellipse O. The second part of the arc and the third part The connection point of the ellipse O is at the starting point F of the arc, and the arc is tangent to the ellipse O at point F. The third part of the connection section The major semi-axis of the ellipse O is a2, The minor semi-axis of the ellipse O is b2,

[0034] The outer contour line of the water guide cone and the contour line of the third part of the connection section are two elliptical segments with the same center and the same eccentricity, satisfying: the eccentricity of the ellipse

[0035] The third part of the connection section is represented in the plane rectangular coordinate system as the ellipse O with the center of the ellipse, the major semi-axis of a2, and the minor semi-axis of b2, at the lower left part,

[0036] a2 = h2 - C = a1 - C,

[0037] The total length of the connection section:

[0038] The connection section is standardized, and it is stipulated that the first-order derivatives at each connection point are continuous and the first-order derivatives at the connection points are the same. This can make the connection section smoother and reduce the uneven flow pattern of the water flow caused by the uneven connection of the connection section and the eddy current generated at the bottom of the trumpet pipe, so as to achieve the vortex elimination effect mentioned in the design.

[0039] As a further improvement of the present invention, the integration of the water inlet flow channel in step S4 includes the following sub-steps:

[0040] After obtaining the flow rate and head required by the design, determine the impeller diameter and the hub diameter; then determine the length, width, height, impeller center height and the size of the water guide cone of the water inlet flow channel; determine the size of the connection section; then draw the overall water inlet flow channel in CAD.

[0041] In view of the unreasonable phenomenon that only the fitting line design is used at the connection section between the inlet flow channel and the impeller inlet in actual engineering, the present invention proposes an intelligent design process based on the collaborative optimization of parametric modeling and fluid dynamics. Through the straight-line-arc-ellipse segmented combination algorithm, the full-parameter connection between the flow channel and the impeller inlet is realized. The present invention is mainly applicable to the box culvert type two-way inlet flow channel. Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a connection method for the connection section between the upper bottom plate of the inlet flow channel and the impeller inlet. For the connection section between the upper bottom plate of the inlet flow channel and the impeller inlet, a set of standardized processes for manufacturing the connection section is provided, no longer relying on the connection through the fitting line, making the method more reasonable and facilitating the implementation by engineering technicians. The present invention designs the upper bottom plate of the inlet flow channel and the water guide cone that are matched with the impeller, improving the flow pattern of the water flow at the inlet flow channel and the impeller inlet, making the pump device more stable during operation; it also optimizes the structural dimensions of the inlet flow channel, making the construction more reasonable and well-founded, and improving the economic benefits and social impacts of the pump station operation to a certain extent. Description of the Drawings

[0042] Figure 1 It is the design dimension drawing of the water guide cone.

[0043] Figure 2 It is the design dimension drawing of the connection section.

[0044] Figure 3 It is the design dimension drawing of the third part of the connection section.

[0045] Figure 4 It is the overall dimension drawing of the water guide cone and the connection section.

[0046] Figure 5 It is the flow chart of the present invention.

[0047] Figure 6 It is the sectional view of the Qinhuai New River inlet flow channel.

[0048] Figure 7 It is the top view of the Qinhuai New River inlet flow channel.

[0049] Figure 8 It is the side view of the Qinhuai New River inlet flow channel. Detailed Embodiment

[0050] As Figure 1-8 shown, it is an automatic vortex control design method for a box culvert type two-way inlet flow channel, including the following steps:

[0051] S1. Determination of impeller parameters:

[0052] (1) According to the flow rate and head of the water pump, restrict nD to be within the range of 350 - 425;

[0053] (2) The specific speed n of the water pumps Coordinated design with rated speed n, according to the pump similarity law formula The specific speed n of the water pump can be obtained s ;

[0054] (3) Dynamic determination of hub diameter D1; In conventional designs, the impeller hub ratio is generally 0.4-0.6, i.e., hub diameter D1 = 0.4-0.6D; the present invention introduces a dynamic hub ratio adaptive algorithm to dynamically adjust the hub range according to the pump operating conditions (flow rate Q, head H):

[0055]

[0056] In the formula, k is the working condition correction coefficient (k = 2 ~ 5)

[0057] The algorithm can optimize the hub diameter according to actual working conditions, break through the limitations of traditional hub ratios, and improve design flexibility;

[0058] (4) Based on the empirical formula of specific speed and hub ratio in water pump:

[0059] Combining the above formulas (1)-(4) we can get the impeller diameter D, the pump rated speed n and the hub ratio This method can achieve coordinated matching of rotation speed and impeller size; considering the integrity of the design, the impeller inlet height h1 is determined to be 0.2~0.3D;

[0060] S2. Determination of water inlet channel size:

[0061] (a) Determination of the length L, width B and height H2 of the water inlet channel:

[0062] The length and width of the straight section of the water inlet flow channel have little effect on the flow field at the inlet of the water pump impeller chamber. The length can be generally determined according to the requirements of the structural layout of the upper part of the pump room in the direction of the water flow. Considering the integrity of the water inlet flow channel design, the overall length of the water inlet flow channel L is determined to be 10~13D; the flow channel width can be determined according to the requirements of the layout of the unit center distance, etc., and also considering the integrity of the design, the water inlet flow channel width B=3.0~4.0D; the determination of the water inlet flow channel height H2 needs to consider the impeller center height. The impeller center height is the most important parameter in the flow channel design. The larger this height is, the better the flow state of the water pump inlet, but the more civil engineering investment of the pump station will be; therefore, taking into account both the water inlet flow state and the civil engineering investment, the impeller center height H1 is determined to be 1.1~1.4D, so the water inlet flow channel height H2 can be determined to be 1.4~1.6D;

[0063] (b) Determination of design dimensions of water guide cone:

[0064] The outer arc shape of the water guide cone is designed to be An ellipse, where the height h2 of the water guide cone is 0.9 - 1.1D. At this time, it should be noted that the sum of the height h2 of the water guide cone and the inlet height h1 of the impeller should be the impeller center height H1, that is, h2 + h1 = H1; the upper width L2 of the water guide cone is the hub diameter D1 minus 0.1D, that is, L2 = D1 - 0.1D; the lower width of the water guide cone is the same as the diameter of the bellmouth, and according to the specification, the diameter D2 of the bellmouth can be determined as 1.4 - 1.7D; from this, the dimensions of the major semi-axis a1 and minor semi-axis b1 of the ellipse of the outer contour line of the water guide cone can be obtained, that is, a1 = h2, As Figure 1 shown;

[0065] S3. Design of the connection section:

[0066] Parametric geometric modeling of the three-section connection section:

[0067] The most important thing in the design of the connection part of the inlet water passage is whether the connection of each section is smooth. This is why multi-segment fitting lines were chosen in most previous designs. However, using multi-segment fitting lines is very ambiguous for parameter design, so it is very inconvenient for construction.

[0068] The connection section designed by the present invention consists of a straight line, an arc and ellipse O, and defines strict mathematical constraint relationships. The specific design is as follows:

[0069] Taking the bottom plate of the inlet water passage as the X-axis and the impeller rotation axis as the Y-axis to establish a plane rectangular coordinate system,

[0070] The first part of the connection section is a straight line segment, starting at a distance of L1 / 2 from the Y-axis, where L1 is the total length of the connection section. The specific length of L1 needs to be determined according to the subsequent dimensions. By this method, the design can be more integral and the mathematical constraints can be stronger. At this time, let the inclination angle of the straight line be α, and the first part of the straight line can be set as y = kx + b, where k = tanα, and the first part of the straight line passes through the point

[0071] Regarding the inclination angle α of the straight line, the value range of the traditional design is 45° - 75°. Here, a dynamic determination method based on the ratio of the flow passage height H2 and the impeller diameter D is proposed:

[0072] α = 50° + 20°·log 10 (H2 / D) (45° ≤ α ≤ 75°)

[0073] By this method, the flow state of the water can be made stable and uniform before entering the bellmouth, and at the same time, the connection between various data is strengthened, making the design of the entire flow passage more integral;

[0074] The second part of the connecting section is an arc with the center O1. To meet the requirement of smoothness of each part of the connecting section, the central angle of the arc should also be α, so that the second part and the first part can be smoothly tangent to meet the design requirements;

[0075] At the same time, it should also be noted that the distance between the lowest point of the arc and the bottom plate of the inlet water passage is the suspended height C of the trumpet pipe, that is, the starting point of the second part of the arc is A suitable suspended height can make the flow velocity and pressure distribution at the pump inlet more uniform, avoid reducing the energy performance and cavitation performance of the pump, and at the same time can effectively avoid the generation of bottom-attached vortices or wall-attached vortices, achieving the effect of vortex elimination; Therefore, it is recommended that the suspended height C = 0.5 - 0.75D; At the same time, based on the simulation data of CFD, an association formula between the suspended height C and the arc radius is established, and the length of the arc radius R is determined based on the optimization of the suspended height C:

[0076]

[0077] Therefore, the second part of the arc should be represented in the plane rectangular coordinate system as an arc with as the center, radius R, and starting point rotating counterclockwise by α, as Figure 2 shown,

[0078] The third part of the connecting section is ellipse O. It is not difficult to find that the connection point between the second part of the arc and the third part ellipse is at the starting point F of the arc, and the arc and the ellipse are tangent at this point, meeting the requirement of smooth connection at the connection;

[0079] The method for determining the dimensions of the major semi-axis a2 and minor semi-axis b2 of the third part of the ellipse is as follows.

[0080] For the design requirement of the inlet water passage between the third part of the connecting section and the guide cone is that the cross-section gradually shrinks. The purpose of this is to ensure that the water flow has a good flow pattern when entering the impeller and ensure that there will be no excessive hydraulic losses. At the same time, it is not difficult to find that when the eccentricities are the same, the cross-sectional area of the ellipse ring enclosed by two different ellipses with the same ellipse center gradually becomes smaller;

[0081] Applying this conclusion to the design of the third section of the connecting section, it can be obtained that to make the cross-section gradually shrink, as long as the outer contour line of the guide cone and the contour line of the third part of the connecting section are two elliptical line segments with the same center and the same eccentricity, that is, satisfying: where a2 = a1 - C,

[0082] Therefore, the third section of the connecting section is represented in the plane rectangular coordinate system as an arc with It is the center of the ellipse. The length of the major axis is a2, and the length of the minor axis is b2. It is located in the lower left part of the ellipse O. where a2 = h2 - C = a1 - C, as Figure 3 shown;

[0083] From this, the connection length of the first section of the connection section can be determined.

[0084]

[0085] Standardization of the connection section: It is stipulated that the first-order derivative is continuous at each connection point and the first-order derivative is the same at the connection point. This can make the connection section smoother and reduce the uneven water flow pattern caused by the uneven connection of the connection section and the eddy current generated at the bottom of the trumpet pipe, so as to achieve the eddy current elimination effect mentioned in the design.

[0086] S4. Integration of the inlet water passage:

[0087] After obtaining the flow rate and head required by the design, determine the impeller diameter and hub diameter; then determine the dimensions of the inlet water passage, including the length, width, height, impeller center height and the dimensions of the water guide cone of the inlet water passage; further determine the dimensions of the connection section, and then draw the overall inlet water passage in CAD, as Figure 4 shown;

[0088] Integrate the above parameters into Table 1:

[0089] Table 1: Parameter integration table

[0090]

[0091] Verification system:

[0092] In order to evaluate the uniformity of the flow pattern to ensure that the flow pattern is uniform before the water enters the impeller inlet, this can reduce the generated eddy current and achieve the purpose of eliminating the eddy current.

[0093] Define the flow pattern uniformity coefficient where ΔV represents the change in flow velocity; V avg represents the average flow velocity. We require the value of U not to exceed 0.92 to ensure the uniformity of the flow pattern. Finally, we can verify this index through instantaneous CFD simulation.

[0094] Select the reconstruction and expansion project of the Qinhuai New River Water Control Project as a specific example;

[0095] The designed flow rate of the newly built pump station in the reconstruction and expansion project of the Qinhuai New River Water Control Project is 100 m 3 / s, and 4 vertical axial flow pumps are installed. The designed flow rate of a single unit is 25 m 3 / s, and the total head is determined to be 4.37 m.

[0096] First, determine the parameters of the impeller. First, through the pump station head and flow rate, we get nD = 350. Then, according to and and Combine these three equations with nD=350 and solve them to get the rated speed of the pump n=125r / min and the impeller diameter D=2.8m. And calculate the hub diameter (Rounding has been done). At the same time, the impeller inlet height is determined to be 0.27D.

[0097] Next, determine the values ​​of the variables required for the design.

[0098] According to the design requirements, the overall length of the water inlet flow channel is determined to be L=12D, the width of the water inlet flow channel is determined to be B=4D, the impeller center height is determined to be H1=1.2D, and the height of the water inlet flow channel is determined to be H2=1.429D.

[0099] Determine the size of the water cone. According to the impeller center height and the impeller inlet height, the height of the water cone can be determined, that is, h2 = H1-h1 = 0.93D. The upper width of the water cone L2 = D1-0.1D; the lower width of the water cone is the diameter of the bell tube D2 = 1.46D. At the same time, determine the outer arc of the water cone The ellipse has a1=h2=0.93D,

[0100] A plane rectangular coordinate system is established with the bottom plate of the water inlet channel as the X-axis and the impeller rotation axis as the Y-axis.

[0101] The first straight line inclination angle α=50°+20°·log 10 (H2 / D) = 53°. The second connecting arc has a central angle of α and a height radius of C = 0.5D, so the arc radius From this, we can get the starting length of the connection segment L1=883cm (rounded off). The dimensions of each part of the Qinhuai New River inlet channel are summarized in Table 2 below, where the data have been rounded off.

[0102] Table 2 Dimensions of each part of the Qinhuai New River inlet channel

[0103]

[0104] From this, we can get the overall layout of the Qinhuai New River inlet channel, as shown in Figure 6-8 Shown are three views of the Qinhuai New River inlet channel.

Claims

1. An automatic vortex control design method for a box culvert type two-way intake flow channel, characterized in that It includes the following steps: S1. Determination of impeller parameters; S2. Determination of the size of the inlet water passage; S3. Design of the connection section; S4. Integration of the inlet water passage.

2. The automatic vortex control design method for a box culvert type two-way intake channel according to claim 1, characterized in that The determination of the impeller parameters in step S1 includes the following formulas: (1) Restrict nD to be between 350 and 425, where n is the rated speed of the pump and D is the impeller diameter; (2) Similarity law formula of water pump n s is the specific speed of the water pump, Q is the flow rate, and H is the head; (3) Dynamically adjust the hub range according to the pump operating conditions: In the formula, D1 is the hub diameter, k is the operating condition correction coefficient, and k = 2 - 5; (4) Empirical formula for specific speed and impeller hub ratio in a water pump: is the impeller hub ratio; Combining the above formulas (1)-(4) we can get the impeller diameter D, the pump rated speed n and the hub ratio 3. The automatic vortex control design method for a box culvert type two-way intake channel according to claim 2, characterized in that, Restrict the impeller inlet height h1 in the impeller parameters to be 0.2 - 0.3D.

4. A method for automatically controlling vortex in a box culvert type two-way inlet flow channel according to any one of claims 1-3, characterized in that, The determination of the size of the inlet water passage in step S2 includes the following sub-steps: (a) Determination of the length L, width B, and height H2 of the inlet water passage: The length L of the inlet water passage = 10 - 13D, the width B of the inlet water passage = 3.0 - 4.0D, the impeller center height H1 = 1.1 - 1.4D, and the height H2 of the inlet water passage = 1.4 - 1.6D; (b) Determination of the design dimensions of the water guide cone: The outer arc shape of the water guide cone is designed as an ellipse. The height h2 of the water guide cone is 0.9 - 1.1D. The sum of the height h2 of the water guide cone and the inlet height h1 of the impeller is the impeller center height H1, i.e., h2 + h1 = H1; Subtract 0.1D from the hub diameter D1 to get the upper width L2 of the water guide cone, L2 = D1 - 0.1D; The lower width of the water guide cone is the same as the diameter of the trumpet pipe. The diameter of the trumpet pipe D2 = 1.4 - 1.7D. The major semi-axis a1 of the ellipse of the outer contour line of the water guide cone is a1 = h2, and the minor semi-axis of the ellipse of the outer contour line of the water guide cone 5. A method for automatically controlling vortex in a box culvert type two-way intake channel according to any one of claims 1-3, characterized in that, The connecting segment in the step S3 includes a straight segment, an arc, and an ellipse O.

6. A method for automatically controlling vortex in a box culvert type two-way intake channel according to claim 5, characterized in that, The parametric geometric modeling of the connection section is as follows: Take the center line of the bottom plate of the inlet water passage as the X-axis and the impeller rotation axis as the Y-axis to establish a plane rectangular coordinate system, The first part of the connection section is a straight line segment, starting at a distance of L1 / 2 from the Y-axis, where L1 is the total length of the connection section, the inclination angle of the straight line is α, and the equation of the first part of the straight line segment is: y = kx + b, where k = tanα, and the first straight line segment passes through the point α = 50° + 20°·log 10 (H2 / D), 45° ≤ α ≤ 75°; The second part of the connecting section is an arc with the center O1 and the central angle of the arc is also α. The distance between the lowest point of the arc and the bottom plate of the inlet channel is the suspended height C of the trumpet pipe. The starting point of the second part of the arc is The suspended height C of the trumpet pipe is 0.5 - 0.75D, and the length of the arc radius R is: The second part of the arc should be represented in the plane rectangular coordinate system as an arc with as the center, radius R, starting point rotating counterclockwise by α; The third part of the connection section is ellipse O, the second part of the arc and the third part The connection point of ellipse O is at the starting point F of the arc, and the arc and ellipse O are tangent at point F. The third part of the connection section The major semi-axis of ellipse O is a2, The minor semi-axis of ellipse O is b2, The outer contour line of the water guide cone and the contour line of the third part of the connection section are two elliptical line segments with the same center and the same eccentricity, satisfying: the eccentricity of the ellipse The third part of the connection segment is represented in the plane rectangular coordinate system as being at the lower left of an ellipse O with as the center of the ellipse, the major semi-axis being a2, and the minor semi-axis being b2. a2 = h2 - C = a1 - C, The total length of the connection section:

7. A method for automatically controlling vortex in a box culvert type two-way intake channel according to any one of claims 1-3, characterized in that, The integration of the inlet water passage in step S4 includes the following sub-steps: After obtaining the required flow rate and head for the design, determine the impeller diameter and the hub diameter; Subsequently, determine the length, width, height, impeller center height, and the size of the water guide cone of the inlet water passage; determine the size of the connection section; and then draw the overall inlet water passage in CAD.

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