Design method of shaft-type water inlet and outlet structure and shaft-type water inlet and outlet structure

Abstract

The application discloses a design method of a shaft type water inlet and outlet structure and the shaft type water inlet and outlet structure, relates to the technical field of water conservancy and hydropower engineering, and comprises the following steps: according to actual engineering operation conditions, initial body type design of the shaft type water inlet and outlet structure is carried out, and basic design parameters of the initial body type of the shaft type water inlet and outlet structure are obtained; the starting end section diameter of a turning section and the end section diameter of the turning section are determined; the turning radius of the turning section, the turning inner diameter of the turning section, the turning outer diameter of the turning section and the length of a connecting diffusion section are calculated; and based on the turning radius of the turning section, the turning inner diameter of the turning section, the turning outer diameter of the turning section, the turning angle of the turning section, the length of the connecting diffusion section and the diffusion angle of the connecting diffusion section, verification is carried out in three-dimensional design software. The application solves the problem of uneven flow distribution of each flow channel caused by the flow deviation of the turning section, and guarantees the safe and stable operation of the water conservancy and hydropower engineering.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower engineering technology, and in particular to a design method and structure for a vertical shaft inlet / outlet. Background Technology

[0002] As a fundamental structure in a pumped storage power station, the vertical shaft inlet and outlet structure is a key component for achieving water flow control and hydropower utilization. Its hydraulic characteristics directly impact the safe and efficient operation of the power station. Under outflow conditions, the presence of bends and the centrifugal force of the water flow at these bends lead to uneven flow distribution across the channels, resulting in planar flow deviation. Summary of the Invention

[0003] The purpose of this invention is to provide a design method and structure for a vertical shaft inlet / outlet structure, which solves the problem of uneven flow distribution in each channel caused by flow deviation in the turning section, so as to ensure the safe and stable operation of hydraulic and hydropower projects.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention provides a design method for a vertical shaft inlet / outlet structure, comprising the following steps:

[0006] Step 1: Based on the actual engineering operating conditions, conduct the initial shape design of the vertical shaft inlet and outlet structure. The basic design parameters of the initial shape of the vertical shaft inlet and outlet structure are as follows: the diameter of the pressurized pipe section is d1, and the diameter of the starting end cross-section of the connecting diffuser section is d. k1 The diameter of the end section of the connecting diffusion section is d. k2 The diameter of the vertical pipe section is d2;

[0007] Step 2: Determine the diameter d of the starting section of the turning segment. z1 and the diameter d of the end section of the turning segment z2 d z1 =d k2 d z2 =d2;

[0008] Step 3: Calculate the turning radius R of the turning segment. m The inner diameter R of the turning section in The outer diameter R of the turning section ex Calculate the length L of the connecting diffusion segment;

[0009] Step 4, based on the turning radius R of the turning segment m The inner diameter R of the turning section in The outer diameter R of the turning section exThe turning angle θ of the turning segment, the length L of the connecting diffuser segment, and the diffusion angle of the connecting diffuser segment. Verification was performed in 3D design software.

[0010] Preferably, the turning radius R of the turning segment m The formula is as follows:

[0011] R m =α·d1

[0012] Where α is the turning radius coefficient, and its value ranges from 2.1 to 2.2.

[0013] Preferably, the inner diameter R of the turning section in The formula is as follows:

[0014] R in =β·d1

[0015] Where β is the turning inner diameter coefficient, β=0.8871·α.

[0016] Preferably, the outer diameter R of the turning section ex The formula is as follows:

[0017] R ex =γ·d1

[0018] Where γ is the turning outer diameter coefficient, γ=1.1987·α.

[0019] Preferably, the turning angle θ of the turning section is 90°.

[0020] Preferably, the formula for the length L of the connecting diffusion section is as follows:

[0021]

[0022] Preferably, the diffusion angle of the connecting diffusion section The range of values ​​is

[0023] The present invention also provides a vertical well inlet / outlet structure obtained by the design method of the vertical well inlet / outlet structure, comprising a pressurized pipe section, a connecting diffuser section, a turning section, a vertical pipe section, a bell mouth section and a trash rack section connected in sequence, wherein the trash rack section is provided with flow channels evenly distributed along the circumference of the trash rack section.

[0024] Preferably, the centerline of the connecting diffusion section is perpendicular to the centerline of the vertical pipe section.

[0025] The present invention achieves the following technical effects compared to the prior art:

[0026] This invention clarifies the design method of the turning section in the vertical shaft inlet / outlet structure by using the turning radius coefficient, turning inner diameter coefficient, and turning outer diameter coefficient; in addition, it introduces the diffusion angle of the connecting diffusion section to adapt to the diversion requirements under different operating flow rates.

[0027] The vertical well inlet / outlet structure obtained by the design method of this invention, compared with the conventional shape where the flow cross-section of the turning section contracts along the flow path, exhibits an expansion followed by contraction along the flow path of the turning section, and the water flow path is shorter (e.g., ...). Figure 2 As shown in the figure, this accelerates the mixing and homogenization of water flow inside the bend section, making the water flow velocity entering the vertical pipe section uniformly distributed in the lateral direction. This effectively solves the adverse effects of the bend flow deviation effect, saves the workload of designers, improves optimization efficiency, and ensures the safe and stable operation of the project. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The vertical well inlet / outlet structure (pressurized pipe section, connecting diffuser section, turning section and vertical pipe section) is obtained by using the design method of the vertical well inlet / outlet structure of the present invention.

[0030] Figure 2 A comparison diagram of the flow cross-sectional diameter variation along the pipe length between the bend section using the present invention and the conventional bend section;

[0031] Figure 3 The image shows the longitudinal profile of the fluid velocity distribution cloud map of the vertical shaft inlet / outlet structure obtained by the design method of the vertical shaft inlet / outlet structure of the present invention.

[0032] Figure 4 The cloud map showing the fluid velocity distribution of each channel of the vertical shaft inlet / outlet structure obtained by the design method of the vertical shaft inlet / outlet structure of the present invention.

[0033] Figure 5 A longitudinal profile of the fluid velocity distribution cloud map for an existing vertical shaft inlet / outlet structure;

[0034] Figure 6 A cloud map showing the fluid velocity distribution in each channel of an existing vertical shaft inlet / outlet structure;

[0035] In the diagram: 1-pressurized pipe section, 2-connecting diffuser section, 3-turning section, 4-vertical pipe section, 5-first flow channel, 6-second flow channel, 7-third flow channel, 8-fourth flow channel, 9-fifth flow channel, 10-sixth flow channel, 11-seventh flow channel, 12-eighth flow channel. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The purpose of this invention is to provide a design method and structure for a vertical shaft inlet / outlet structure, which solves the problem of uneven flow distribution in each channel caused by flow deviation in the turning section, so as to ensure the safe and stable operation of hydraulic and hydropower projects.

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] like Figure 1 As shown in the figure, this embodiment provides a design method for a vertical shaft inlet / outlet structure, including the following steps:

[0041] Step 1: Based on the actual engineering operating conditions, conduct the initial shape design of the vertical shaft inlet and outlet structure. The basic design parameters of the initial shape of the vertical shaft inlet and outlet structure are as follows: the diameter of the pressurized pipe section 1 is d1 = 7.20m, and the diameter of the initial section of the connecting diffuser section 2 is d1 = 7.20m. k1 =7.21m, the diameter of the end section of the connecting diffuser section 2 is d k2 =10.00m, the diameter of vertical pipe section 4 is d2=7.50m;

[0042] Step 2: Determine the diameter d of the starting section of turning segment 3. z1 and the diameter d of the end section of the turning segment 3 z2 d z1 =d k2 =10.00m, d z2 =d2=7.50m;

[0043] Step 3: Calculate the turning radius R of turning segment 3. m The inner diameter R of turning section 3 in The outer diameter R of turning segment 3 exCalculate the length L of the connecting diffusion segment 2;

[0044] In this embodiment, the turning radius R of turning segment 3 m The formula is as follows:

[0045] R m =α·d1

[0046] Where α is the turning radius coefficient, with a value ranging from 2.1 to 2.2. In this embodiment, it is taken as 2.15. The turning radius R of turning segment 3 is calculated. m =15.50m;

[0047] In this embodiment, the inner diameter R of the turning segment 3 in The formula is as follows:

[0048] R in =β·d1

[0049] Where β is the turning inner diameter coefficient, β=0.8871·α, the turning inner diameter R of turning segment 3 is calculated. in =13.75m;

[0050] In this embodiment, the outer diameter R of the turning segment 3 ex The formula is as follows:

[0051] R ex =γ·d1

[0052] Where γ is the turning outer diameter coefficient, γ = 1.1987·α, the turning outer diameter R of turning segment 3 is calculated. ex =18.58m;

[0053] In this embodiment, the turning angle θ of the turning segment 3 (the turning angle is the angle between the starting end section and the ending end section of the turning segment 3) is 90°.

[0054] In this embodiment, the formula for the length L of the connecting diffusion segment 2 is as follows:

[0055]

[0056] In this embodiment, the diffusion angle connecting diffusion segment 2 is... (The diffusion angle of connecting diffusion segment 2 is the angle between the inner wall of connecting diffusion segment 2 and the centerline of connecting diffusion segment 2) has a range of values ​​of [value missing]. The value is set based on the traffic volume;

[0057] In this embodiment, Taking 5.3°, the length of the connecting diffusion section 2 is calculated to be L = 15m;

[0058] Step 4, based on the turning radius R of turning segment 3 m The inner diameter R of turning section 3 in The outer diameter R of turning segment 3 ex The turning angle θ of turning segment 3, the length L of connecting diffuser segment 2, and the diffusion angle of connecting diffuser segment 2. Verification was performed in 3D design software.

[0059] This embodiment clarifies the design method of the turning section 3 in the vertical shaft inlet / outlet structure by defining the turning radius coefficient, turning inner diameter coefficient, and turning outer diameter coefficient; in addition, the diffusion angle connecting the diffusion section 2 is also introduced. To adapt to the diversion requirements under different operating flow rates. The vertical well inlet and outlet structure obtained by the design method of this embodiment can effectively solve the problem of uneven flow distribution in each channel caused by the flow deviation effect in the turning section 3, thereby saving the workload of designers, improving optimization efficiency, and ensuring the safe and stable operation of the project.

[0060] Example 2

[0061] like Figure 1 As shown, this embodiment provides a vertical well inlet / outlet structure obtained by the design method of the vertical well inlet / outlet structure of Embodiment 1. According to the water flow direction, it includes a pressurized pipe section 1, a connecting diffuser section 2, a turning section 3, a vertical pipe section 4, a bell-shaped section, and a trash rack section connected in sequence. The trash rack section is provided with flow channels evenly distributed along its circumference. The diameter of the starting end cross-section of the turning section 3 is equal to the diameter of the ending end cross-section of the connecting diffuser section 2, and the diameter of the ending end cross-section of the turning section 3 is equal to the diameter of the vertical pipe section 4. The centerline of the connecting diffuser section 2 is perpendicular to the centerline of the vertical pipe section 4.

[0062] Comparative Example

[0063] When the unit operates with both units running, according to current design manuals and specifications, the turning radius of turning section 3 is designed to be 2.77 times the diameter of the pressurized tunnel. Analysis of the longitudinal profile velocity distribution and fluid velocity distribution in each channel of the existing vertical shaft inlet / outlet structure of turning section 3 shows that, for example… Figure 5 and Figure 6 As shown, due to the flow deflection effect at the bend, the velocity distribution entering the vertical pipe section 4 is uneven. Consequently, the fluid velocity in the four channels near the outer side of the bend section 3 (channel 7, channel 8, channel 9, and channel 10) is significantly higher than that in the four channels near the inner side of the bend section 3 (channel 5, channel 6, channel 7, and channel 8), ultimately resulting in uneven fluid flow distribution in each channel, as shown in Table 1. The existing bend section 3 causes significant uneven flow distribution at the inlet and outlet orifices, which is detrimental to the safe and stable operation of the project.

[0064] After the design method of the vertical shaft inlet and outlet structure in this embodiment is adjusted, as follows: Figure 3 As shown, the flow velocity of the fluid entering vertical pipe section 4 is uniformly distributed laterally; as Figure 4 As shown, the velocity distribution of the fluid entering each channel becomes more uniform, thereby improving the uniformity of fluid flow distribution in each channel.

[0065] Table 1 Comparison of fluid flow distribution in each channel under the outflow condition of this embodiment and the original scheme.

[0066]

[0067] The flow distribution of fluids in each channel under the outflow conditions in this embodiment and the original scheme is shown in Table 1. It can be seen that after redesigning the turning section 3 and the vertical pipe section 4 according to the method of this embodiment, the problem of uneven flow distribution caused by the bend flow deflection effect in the vertical well inlet and outlet structure is solved.

[0068] Example 3

[0069] When the unit is operating alone, the operating flow rate decreases to 59.2 m³ / h. 3 / s Taking an angle of 3.2°, and calculating the length of the connecting diffuser section 2 as L = 25m, the flow distribution ratios for each channel were obtained as 10.91%, 11.19%, 14.70%, 11.59%, 15.71%, 13.56%, 13.67%, and 8.67%, respectively. Observing the comparison results in Table 2, it can be seen that when a single unit is running, the inlet and outlet flow rates decrease. In the existing technology, the flow distribution ratio for each channel ranges from 7.32% to 19.01%, indicating uneven flow distribution. In contrast, this invention, by adjusting the length of the connecting diffuser section, achieves a flow distribution ratio for each channel ranging from 8.67% to 15.71%, significantly improving the problem of uneven flow distribution during single-unit operation.

[0070] Table 2 Comparison of fluid flow distribution in each channel under the outflow conditions of this embodiment and the original scheme.

[0071]

[0072] To further demonstrate the reliability of this embodiment, the vertical shaft inlet / outlet structure of this embodiment was manufactured using 3D printing technology. Experiments were conducted to monitor the fluid flow distribution in each channel of the vertical shaft inlet / outlet structure under both dual-machine and single-machine operating flow rates. Table 3 compares the experimental and numerical simulation results of the flow split ratio for each channel of the vertical shaft inlet / outlet structure. Observing the comparison results in Table 3, it can be seen that the distribution patterns of the numerical simulation values ​​and experimental values ​​are consistent, proving the reliability of the design method of the vertical shaft inlet / outlet structure of this embodiment.

[0073] Table 3 Comparison of experimental and simulated values ​​of fluid flow distribution in each channel under different operating flow rates for vertical shaft inlet and outlet structures.

[0074]

[0075] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A design method for a vertical shaft-type inlet / outlet structure, characterized by: Includes the following steps: Step 1: Based on the actual engineering operating conditions, conduct the initial shape design of the vertical shaft inlet and outlet structure. The basic design parameters of the initial shape of the vertical shaft inlet and outlet structure are as follows: The diameter of the pressurized pipe section is... The diameter of the starting section of the connecting diffusion segment is The diameter of the end section of the connecting diffusion section is The diameter of the vertical pipe section is ; Step 2: Determine the diameter of the starting section of the turning segment. and the diameter of the end section of the turning segment , , ; Step 3: Calculate the turning radius of the turning segment. The inner diameter of the turning section The outer diameter of the turning section Calculate the length of the connecting diffusion segment. ; Step 4, based on the turning radius of the turning segment The inner diameter of the turning section The outer diameter of the turning section Turning angle of the turning section Length of the connecting diffusion section and the diffusion angle of the connecting diffusion segment Verification was performed in 3D design software; Turning radius of the turning section The formula is as follows: in, This is the turning radius coefficient, with a value ranging from 2.1 to 2.2; inner diameter of the turning section The formula is as follows: in, This is the inner diameter coefficient for turning. ; outer diameter of the turning section The formula is as follows: in, The outer diameter coefficient for turning ; Turning angle of the turning section It is 90°; Length of the connecting diffusion section The formula is as follows: ； Diffusion angle of the connecting diffusion segment The range of values ​​is 0. < ; The vertical well inlet / outlet structure obtained by the design method of the vertical well inlet / outlet structure includes, according to the water flow direction, a pressurized pipe section, a connecting diffuser section, a turning section, a vertical pipe section, a bell mouth section and a trash rack section connected in sequence. The trash rack section is provided with flow channels evenly distributed along the circumference of the trash rack section.

2. The design method for the vertical shaft inlet / outlet structure according to claim 1, characterized in that: The centerline of the connecting diffusion section is perpendicular to the centerline of the vertical pipe section.

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