Flow measuring method for variable cross-section spillway tunnel

Abstract

The invention discloses a variable cross-section spillway tunnel flow measurement method, and belongs to the technical field of hydraulic engineering, and the method comprises the following steps: S1, constructing an experiment system, the experiment system comprises a reservoir, a stilling pool and a plurality of experiment pipelines arranged in parallel, and the inlet end and the outlet end of each experiment pipeline are respectively communicated with the reservoir and the stilling pool; s2, selecting a target experimental pipeline: determining the shape of a to-be-tested variable cross-section flood discharge tunnel, and selecting the corresponding target experimental pipeline, so that the inlet end and the outlet end of the target experimental pipeline are respectively communicated with the reservoir and the stilling pool; s3, running the experiment and measuring data: supplying water into the reservoir, and measuring the flow velocity, pressure and water level in the target experiment pipeline; and S4, switching and repeating experiments: when another form of variable cross-section spillway tunnel needs to be tested, closing the inlet end of the current target experiment pipeline, and repeating the steps S2 and S3. The device has the effects of conveniently and quickly realizing data determination of experimental pipelines in different forms and improving the experimental efficiency.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering, and in particular to a method for measuring flow in a variable cross-section spillway. Background Technology

[0002] In the field of water conservancy engineering, variable cross-section spillway tunnels are common structures, and accurate flow measurement is crucial for reservoir flood control scheduling, rational water resource utilization, and engineering safety assessment. The variable cross-section flow measurement method based on Bernoulli's principle has become an important flow measurement technique in this scenario due to its mature theory, high reliability, and the fact that it does not require additional measuring equipment.

[0003] To ensure the accuracy and reliability of this flow measurement method, it is generally thoroughly verified through physical model experiments before its practical application in large-scale projects. In existing technologies, a typical setup for such simulation experiments typically includes a reservoir simulating an upstream reservoir, an experimental pipeline simulating a specific variable cross-section spillway, and a stilling basin for energy dissipation and stabilizing the downstream water level. The setup uses a water pump to supply water, and relevant measuring instruments are installed on the experimental pipeline to determine key parameters such as flow velocity, pressure, and water level.

[0004] However, in actual use, the above-mentioned existing technical solutions are often problematic because variable cross-section spillways are usually composed of contraction sections, transition sections, and gradual change sections. In order to simulate the shape of spillways with different section ratios and obtain comprehensive measurement data, researchers must frequently stop the experiment and manually replace the experimental pipes of different shapes. This process is cumbersome, time-consuming, and labor-intensive, which greatly reduces the efficiency of the experiment. Summary of the Invention

[0005] To facilitate rapid data measurement of experimental pipelines of different shapes and improve experimental efficiency, this application provides a flow measurement method for variable cross-section spillway tunnels.

[0006] The flow measurement method for a variable cross-section spillway tunnel provided in this application adopts the following technical solution: A flow measurement method for a variable cross-section spillway includes the following steps: S1, constructing an experimental system, which includes a reservoir, a stilling basin, and multiple experimental pipes connected in parallel. The inlet and outlet of each experimental pipe are connected to the reservoir and the stilling basin, respectively, and each experimental pipe has different morphological parameters; S2, selecting a target experimental pipe: determining the shape of the variable cross-section spillway to be tested, selecting the corresponding target experimental pipe, ensuring that the inlet and outlet of the target experimental pipe are connected to the reservoir and the stilling basin, respectively, while closing the inlet of the remaining non-target experimental pipes; S3, running the experiment and measuring data: supplying water to the reservoir, with the water flowing into the stilling basin through the target experimental pipe; during this period, measuring the flow velocity, pressure, and water level in the target experimental pipe; S4, switching and repeating the experiment: when it is necessary to test a different type of variable cross-section spillway, closing the inlet of the current target experimental pipe and repeating steps S2 and S3; continuously selecting new target experimental pipes for testing, and completing the experiment when all experimental pipes have been tested.

[0007] By adopting the above technical solution, when it is necessary to simulate the morphology of flood discharge tunnels with different segment ratios to obtain comprehensive measurement data, researchers only need to open the inlet end of the target experimental pipe and close the inlet ends of other experimental pipes. There is no need to frequently stop the experiment and manually replace experimental pipes of different morphologies. The operation is simple, time-saving, and labor-saving, which helps to improve experimental efficiency. Moreover, the fact that there is no need to repeatedly replace the experimental pipes during this process also makes the experimental pipes less prone to wear, thus reducing the likelihood of installation errors or leaks, which helps to ensure the accuracy of experimental data.

[0008] Optionally, in step S3, water is supplied to the reservoir via a circulating water pump. The input end of the circulating water pump is connected to the stilling basin via a pipe, and the output end is connected to the reservoir via a pipe. An electromagnetic flow meter is installed on the pipe connecting the circulating water pump to the reservoir.

[0009] By adopting the above technical solution, the setting of the circulating water pump facilitates the recycling of water resources, which is conducive to saving water resources. At the same time, the setting of the electromagnetic flow meter can detect the total water output and determine whether the water supply is normal, thus ensuring the stability of the experiment.

[0010] Optionally, the water storage tank is equipped with a water stabilizing device, which includes a water stabilizing pipe and a water stabilizing filter pad. The water stabilizing pipe is connected to a pipe connected to the output end of the circulating water pump. The outer circumferential surface of the water stabilizing pipe has multiple water passage holes, and the water stabilizing filter pad covers the water stabilizing pipe.

[0011] By adopting the above technical solution, the water stabilizing pipe and water stabilizing filter pad can effectively dissipate the turbulent energy when water flows in, reduce the water flow velocity, and facilitate more stable detection of water flow parameters. At the same time, the water stabilizing filter pad can help reduce impurities in the water and reduce the impact of impurities on the experiment.

[0012] Optionally, the top of the experimental pipe is provided with multiple detection holes distributed along its own length, and the detection holes are equipped with a flow meter for measuring the water flow velocity and a water level gauge for measuring the water level height.

[0013] By adopting the above technical solution, multiple detection holes distributed along the length of the pipeline facilitate the simultaneous detection of flow velocity and water level at multiple points in the experimental pipeline using a flow meter and a water level gauge. This method is convenient to operate and helps to reduce single-point measurement errors, ensuring the accuracy of experimental measurement parameters.

[0014] Optionally, the experimental pipeline includes a contraction section, a transition section, a gradual section, and a stable section arranged sequentially from the direction near the water storage tank to the direction away from the water storage tank. The stable section of each experimental pipeline has the same length, and the detection hole is opened in the stable section.

[0015] By adopting the above technical solution, the test variables are separated by stable segments of the same length, which helps to reduce water flow fluctuations caused by unstable flow conditions and obtain more stable measurement data.

[0016] Optionally, the water storage tank is provided with flow outlets corresponding to each experimental pipe. The inlet end of each target experimental pipe is connected to and installed at each flow outlet. The water storage tank is provided with a blocking assembly, which includes a mounting plate and a blocking plate. The mounting plate is installed in the water storage tank. Multiple blocking plates are provided corresponding to each flow outlet. Each blocking plate slides vertically and engages with the mounting plate. Each blocking plate is used to open and close each flow outlet.

[0017] By adopting the above technical solution, and by setting an independent flow outlet and an independently controllable baffle for each experimental pipeline, it is easy to achieve precise and rapid opening and closing control of each experimental pipeline.

[0018] Optionally, the mounting plate is provided with a return spring corresponding to each of the blocking plates. Under normal conditions, the blocking plates open the outlet under the elastic force of the return springs. The blocking plates are provided with wedge-shaped locking blocks and locking springs. The bottom of the wedge-shaped locking blocks is a wedge-shaped surface. A locking groove is provided on one side of the blocking plate. The wedge-shaped locking blocks slide and engage with the locking groove. The locking springs are provided in the locking grooves and apply an elastic force to the wedge-shaped locking blocks to move away from the blocking plates. The mounting plate is provided with locking holes corresponding to each of the wedge-shaped locking blocks and engaging with them. When the wedge-shaped locking blocks are engaged with the locking holes, the blocking plates close the outlet. An unlocking component is provided in the locking holes to push the wedge-shaped locking blocks out of the locking holes.

[0019] By adopting the above technical solution, pressing down on one of the blocking plates allows the wedge-shaped locking block to engage with the locking hole, thus sealing one of the flow outlets, i.e., the inlet end of the experimental pipe. This makes it convenient and quick for operators to seal one of the flow outlets, i.e., the inlet end of the experimental pipe.

[0020] Optionally, the unlocking component includes an unlocking block and an unlocking spring. One end of the unlocking block is located inside the locking hole, and the other end passes through and slides against the mounting plate. The unlocking spring is located inside the locking hole and applies a spring force to the unlocking block to move away from the blocking plate.

[0021] By adopting the above technical solution, when the unlocking block is pressed and pushes the locking block out of the locking hole, the blocking plate moves upward under the elastic force of the reset spring, thereby realizing the opening of the convection outlet, i.e. the inlet section of the experimental pipe. The researchers can conveniently and quickly close and open the convection outlet, i.e. the inlet section of the experimental pipe.

[0022] Optionally, each of the experimental pipes has multiple pressure measuring holes distributed along its own length at its bottom, and each pressure measuring hole is connected to a pressure measuring pipe; a pressure bar is provided on one side of the water storage tank, and the pressure bar includes pressure measuring cylinders that are arranged one-to-one with the pressure measuring holes, and each pressure measuring cylinder is connected to a connecting pipe.

[0023] By adopting the above technical solution, when testing a certain experimental pipeline, the pressure measuring pipe at the bottom of the experimental pipeline is connected to each connecting pipe, so that the pressure at different positions at the bottom of the experimental pipeline can be intuitively reflected by the water column height of each pressure measuring cylinder, which is convenient and intuitive.

[0024] Optionally, the pressure testing pipe is provided with a male connector, and the connecting pipe is provided with a female connector corresponding to the male connector. When the connecting pipe is connected to the female connector, the pressure testing pipe and the connecting pipe are connected.

[0025] By adopting the above technical solution, the setting of male and female connectors makes the connection between the pressure testing pipeline and the connecting pipeline convenient and quick, and facilitates the rapid disassembly and assembly of the male and female connectors, thereby improving the efficiency of experimental testing.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. When it is necessary to simulate the morphology of spillway with different segment ratios in order to obtain comprehensive measurement data, researchers only need to open the inlet end of the target experimental pipe and close the inlet ends of other experimental pipes. There is no need to frequently stop the experiment and manually replace the experimental pipes of different morphologies. The operation is simple, time-saving and labor-saving, which helps to improve experimental efficiency.

[0027] 2. The installation of water stabilizing pipes and water stabilizing filter pads facilitates the dissipation of turbulent energy during water inflow, reduces water flow velocity, and facilitates more stable detection of water flow parameters. At the same time, the installation of water stabilizing filter pads helps to reduce impurities in the water and reduce the impact of impurities on the experiment.

[0028] 3. Multiple detection holes distributed along the length of the pipeline facilitate simultaneous flow velocity and water level detection at multiple points in the experimental pipeline using a flow meter and a water level gauge. This makes operation convenient and helps reduce single-point measurement errors, ensuring the accuracy of experimental measurement parameters. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0030] Figure 2 This is a schematic diagram of the overall structure from another perspective of an embodiment of this application.

[0031] Figure 3 This is a partial cross-sectional schematic diagram of the barrier plate in an embodiment of this application.

[0032] Figure 4 This is a partial cross-sectional view of the male connector and the female connector in an embodiment of this application.

[0033] Explanation of reference numerals in the attached figures: 1. Water storage tank; 2. Stilling basin; 3. Experimental pipeline; 301. Contraction section; 302. Transition section; 303. Gradual change section; 304. Stabilizing section; 4. Detection hole; 5. Flow meter; 6. Water level gauge; 7. Outlet; 8. Mounting plate; 9. Baffle plate; 10. Return spring; 11. Wedge locking block; 111. Wedge surface; 12. Locking spring; 13. Locking groove; 14. Locking hole; 15. Unlocking block; 151. Unlocking slider; 16. Unlocking spring; 17. Unlocking hole; 18. Circulating water pump; 19. Electromagnetic flow meter; 20. Stabilizing pipe; 21. 21. Stabilizing filter pad; 22. Water passage hole; 23. Pressure testing pipe; 24. Pressure testing cylinder; 25. Connecting pipe; 26. Connecting male connector; 261. First connecting cavity; 262. Connecting spring; 263. Connecting sealing gasket; 264. Connecting rod; 265. Male connector fixing part; 266. Male connector fixing hole; 27. Connecting female connector; 271. Second connecting cavity; 2711. Connecting section; 2712. Insertion section; 272. Connecting fixing rod; 273. Pressing sliding part; 2731. Pressing receiving groove; 274. Pressing spring; 28. Insertion receiving hole; 29. ​​Fixing ball. Detailed Implementation

[0034] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0035] This application discloses a flow measurement method for a variable cross-section spillway tunnel. (Refer to...) Figure 1 The flow measurement method for variable cross-section spillway tunnels includes the following specific steps: S1, constructing an experimental system, which includes a reservoir 1, a stilling basin 2, and multiple experimental pipes 3 connected in parallel. The inlet and outlet ends of each experimental pipe 3 are connected to the reservoir 1 and the stilling basin 2, respectively, and each experimental pipe 3 has different morphological parameters.

[0036] Reference Figure 1 and Figure 2 Specifically, the top of the stilling basin 2 is open, and the outlet end of each experimental pipe 3 is located at the top of the opening of the stilling basin 2. In this embodiment, six experimental pipes 3 are provided, with two adjacent experimental pipes 3 forming a group. Each experimental pipe 3 includes a contraction section 301, a transition section 302, a gradual change section 303, and a stabilizing section 304 arranged sequentially from the direction near the water storage tank 1 to the direction away from the water storage tank 1. The cross-sectional size of the contraction section 301 gradually decreases, the cross-sectional size of the transition section 302 is equal, the cross-sectional size of the gradual change section 303 gradually increases, and the cross-sectional size of the stabilizing section 304 is equal to and larger than the cross-sectional size of the transition section 302.

[0037] Continue to refer to Figure 1 and Figure 2In each experimental pipe 3, the length of the stable section 304 is the same. In each pair of experimental pipes 3, at least one parameter of the contraction section 301, transition section 302, and gradual change section 303 is fixed, while the length ratio of the other two parameters is different. The stable sections 304 of the same length separate the test variables, which helps to reduce the water flow fluctuations caused by the instability of the flow state and obtain more stable measurement data.

[0038] Reference Figure 1 Each experimental pipe 3 has multiple detection holes 4 evenly distributed along its length at the top of the stable section 304. In this embodiment, the number of detection holes 4 is six. Each detection hole 4 is equipped with a flow meter 5 for measuring water flow velocity and a water level gauge 6 for measuring water level height. This allows for simultaneous flow velocity and water level detection at multiple points in the experimental pipe 3 through the flow meter 5 and water level gauge 6, which is convenient to operate and helps reduce single-point measurement errors.

[0039] S2. Select the target test pipe: Determine the shape of the variable cross-section spillway to be tested, select the corresponding target test pipe 3, and keep the inlet and outlet ends of the target test pipe 3 connected to the reservoir 1 and the stilling basin 2 respectively, while closing the inlet ends of the other non-target test pipes 3.

[0040] Reference Figure 1 and Figure 2 Specifically, the water storage tank 1 is provided with six outlets 7, each corresponding to one of the experimental pipes 3. The inlet end of each target experimental pipe is connected to and installed at each outlet 7. The water storage tank 1 is provided with a blocking assembly, which includes a mounting plate 8 and a blocking plate 9. The mounting plate 8 is installed in the water storage tank 1, and multiple blocking plates 9 are provided corresponding to each outlet 7. Each blocking plate 9 slides vertically and engages with the mounting plate 8. When each blocking plate 9 is located near the bottom of the water storage tank 1, each blocking plate 9 closes each outlet 7.

[0041] Reference Figure 2 and Figure 3 Furthermore, the mounting plate 8 is provided with six sets of reset springs 10 that correspond one-to-one with the blocking plate 9. Each set of reset springs 10 has two springs and is located on both sides of the blocking plate 9. One end of each reset spring 10 is connected to the top of the mounting plate 8 and the other end is connected to the blocking plate 9 to apply a vertical upward elastic force to the blocking plate 9. Under normal conditions, the blocking plate 9 opens the outlet 7 under the elastic force of the reset springs 10.

[0042] Reference Figure 3The blocking plate 9 is provided with a wedge-shaped locking block 11 and a locking spring 12. The bottom of the wedge-shaped locking block 11 is a wedge-shaped surface 111. The blocking plate 9 has a locking groove 13 on the side facing the mounting plate 8. The wedge-shaped locking block 11 slides and engages with the locking groove 13. One end of the locking spring 12 is connected to the groove wall of the locking groove 13 away from its own opening, and the other end is connected to the wedge-shaped locking block 11, so as to apply a spring force to the wedge-shaped locking block 11 to move away from the blocking plate 9.

[0043] Reference Figure 2 and Figure 3 The mounting plate 8 has six locking holes 14 on the side facing the baffle plate 9, each corresponding to and engaging with the wedge-shaped locking blocks 11. When the wedge-shaped locking blocks 11 are engaged in the locking holes 14, each baffle plate 9 closes the flow outlet 7. Pressing down on one of the baffle plates 9 causes the wedge-shaped locking blocks 11 to engage in the locking holes 14, thus closing one of the flow outlets 7, i.e., the inlet end of the experimental pipe 3. This operation allows operators to quickly and easily close one of the flow outlets 7, i.e., the inlet end of the experimental pipe 3.

[0044] Continue to refer to Figure 2 and Figure 3 To facilitate the release of the wedge-shaped locking block 11 from the locking hole 14 to unlock the baffle plate 9 and thus open the outlet 7 (i.e., the inlet section of the experimental pipe 3), an unlocking assembly is provided inside the locking hole 14. The unlocking assembly includes an unlocking block 15 and an unlocking spring 16. One end of the unlocking block 15 is located inside the locking hole 14, and the other end passes through and slides against the mounting plate 8 on the side away from the baffle plate 9. The wall of the locking hole 14 has an unlocking hole 17 extending along its own length. The unlocking block 15 is fixedly connected to an unlocking slider 151 that slides within the unlocking hole 17. One end of the unlocking spring 16 is connected to the wall of the unlocking hole 17, and the other end is connected to the unlocking slider 151, so as to apply a spring force to the unlocking block 15 in the direction away from the baffle plate 9, thereby facilitating the reset of the unlocking block 15 by pressing the unlocking block 15 to push the locking block out of the locking hole 14.

[0045] S3. Run the experiment and measure the data: Supply water to the reservoir 1, and the water flows into the stilling basin 2 through the target experimental pipe 3; during this period, measure the flow velocity, pressure and water level in the target experimental pipe 3.

[0046] Reference Figure 1 Specifically, in this step, water is mainly supplied to the water storage tank 1 through the circulating water pump 18. The input end of the circulating water pump 18 is connected to the stilling tank 2 through a pipe, and the output end is connected to the water storage tank 1 through a pipe. An electromagnetic flow meter 19 is installed on the pipe connecting the circulating water pump 18 to the water storage tank 1 to detect the total water output and determine whether the water supply is normal, so as to ensure the stability of the experiment.

[0047] Reference Figure 1 and Figure 2 Furthermore, a water stabilizing device is also installed in the water storage tank 1. The water stabilizing device includes a water stabilizing pipe 20 and a water stabilizing filter pad 21. The water stabilizing pipe 20 is fixedly installed in the water storage tank 1 and connected to the pipe connected to the output end of the circulating water pump 18. Multiple water passage holes 22 are opened on the outer circumferential surface of the water stabilizing pipe 20. The water passage holes 22 are distributed in a rectangular array on the water stabilizing pipe 20. The water stabilizing filter pad 21 covers the water stabilizing pipe 20 to reduce the water flow velocity and more stably realize the detection of water flow parameters. At the same time, the setting of the water stabilizing filter pad 21 helps to reduce the impurities contained in the water and reduce the influence of impurities on the experiment.

[0048] Reference Figure 2 Each experimental pipe 3 has multiple pressure measuring holes (not shown in the figure) distributed along its length at its bottom. In this embodiment, six pressure measuring holes are selected, and each pressure measuring hole is connected to a pressure measuring pipe 23. A pressure bar is provided on one side of the water storage tank 1. The pressure bar includes pressure measuring cylinders 24, each corresponding to one of the pressure measuring holes. Each pressure measuring cylinder 24 is a transparent hollow cylinder, and each pressure measuring cylinder 24 is connected to a connecting pipe 25 at its bottom. When testing one of the experimental pipes 3, the pressure measuring pipe 23 at the bottom of the experimental pipe 3 is connected to each connecting pipe 25, so that the pressure at different positions at the bottom of the experimental pipe 3 can be visually reflected by the height of the water column in each pressure measuring cylinder 24.

[0049] Continue to refer to Figure 2 To facilitate the connection between the pressure testing pipe 23 and the connecting pipe 25, each pressure testing pipe 23 is equipped with a male connector 26, and each connecting pipe 25 is equipped with a female connector 27 corresponding to the male connector 26. Under normal conditions, the male connector 26 and the female connector 27 respectively close the pressure testing pipe 23 and the connecting pipe 25. When the connecting pipe is connected to the female connector 27, the pressure testing pipe 23 and the connecting pipe 25 are connected.

[0050] Reference Figure 2 and Figure 4Specifically, the male connector 26 is threadedly installed at one end of the pressure testing pipe 23. The male connector 26 has a first connecting cavity 261 that communicates with the pressure testing pipe 23. The male connector 26 is equipped with a connecting opening and closing component for opening and closing the first connecting cavity 261. The connecting opening and closing component includes a connecting spring 262, a connecting sealing gasket 263, and a connecting rod 264. The male connector 264 is fixedly connected to a male connector fixing part 265, and the connecting rod 264 is coaxially slidably fitted to the male connector fixing part 265. The connecting sealing gasket 263 is fixedly installed on the connecting rod 264, and the connecting spring 262 is sleeved on the outside of the connecting rod 264. One end of the connecting spring 262 is connected to the connecting sealing gasket 263, and the other end is connected to the male connector fixing part 265, so that under normal conditions, the connecting rod 264 drives the connecting sealing gasket 263 to close the opening of the first connecting cavity 261 under the elastic force of the connecting spring 262.

[0051] The female connector 27 is threadedly installed at one end of the connecting pipe 25. The female connector 27 has a second connecting cavity 271 connected to the connecting pipe 25. The second connecting cavity includes a connecting section 2711 connected to the connecting pipe 25 and a plug-in section 2712 connected to the end of the connecting section 2711 away from the connecting pipe 25. The male connector 26 is plugged into the plug-in section 2712. A connecting fixing rod 272, corresponding to the connecting rod 264, is coaxially fixed inside the female connector 27. When the male connector 26 is plugged into the plug-in section 2712 of the female connector 27, the connecting fixing rod 272 pushes the connecting rod 264, causing the connecting sealing gasket 263 to move away from the female connector 27, thereby achieving communication between the first connecting cavity 261 and the second connecting cavity 271.

[0052] To ensure the stability of the male connector 26 when it is inserted into the connector section 2712, a ring of male connector fixing holes 266 is formed on the outer circumference of the male connector 26, which are closed at both ends and arranged in a ring shape. The inner wall of the connector section 2712 has a plurality of insertion receiving holes 28 arranged around its own axis. Each insertion receiving hole 28 is provided with a fixing ball 29. Each fixing ball 29 corresponds to and is inserted into the male connector fixing hole 266. When the male connector 26 is inserted into the connector section of the female connector 27, each fixing ball 29 limits the position of the female connector 27 by engaging with the male connector fixing hole 266.

[0053] To ensure the stability of the retaining ball 29 when it is located within the male connector retaining hole 266, and to facilitate unlocking between the male connector 26 and the female connector 27, the outer circumferential surface of the female connector 27 is provided with a pressing sliding part 273 and a pressing spring 274. The pressing sliding part 273 slides and engages with the outer circumferential surface of the female connector 27. The inner wall of the pressing sliding part 273 has a pressing receiving groove 2731 extending along its own axis. The pressing spring 274 is located within the pressing receiving groove 2731. One end of the pressing spring 274 is connected to the pressing sliding part 273, and the other end... The end is connected to the male connector 26. In normal operation, the sliding part 273 presses against the fixed ball 29 under the elastic force of the pressing spring 274 to ensure the stability of the fixed ball 29 when it is located in the fixing hole 266 of the male connector. When the sliding part 273 is pressed to release the pressure on the fixed ball 29, the fixed ball 29 can move away from the male connector 26 in the insertion receiving hole 28 under the action of the component force, thereby facilitating the release of the fixation between the male connector 26 and the female connector 27, which is convenient and quick.

[0054] S4. Switching and repeating the experiment: When it is necessary to test another type of variable cross-section spillway, close the inlet end of the current target experimental pipe 3 and repeat steps S2 and S3; continuously select new target experimental pipes 3 for testing, and complete the experiment when all experimental pipes 3 have been tested.

[0055] The implementation principle of the variable cross-section spillway flow measurement method in this application embodiment is as follows: When it is necessary to simulate the shape of a spillway with different section ratios to obtain comprehensive measurement data, researchers only need to open the inlet end of the target experimental pipe 3 and close the inlet ends of other experimental pipes 3 by moving the baffle plate 9. There is no need to frequently stop the experiment and manually replace the experimental pipes 3 with different shapes. The operation is simple, time-saving and labor-saving, which is conducive to improving experimental efficiency. Moreover, the fact that the experimental pipes 3 do not need to be replaced repeatedly in this process also makes the experimental pipes 3 less prone to wear, and thus less prone to installation errors or water leakage, which is conducive to ensuring the accuracy of experimental data.

[0056] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for measuring flow in a variable cross-section spillway, characterized in that: The specific steps include: S1, constructing an experimental system, which includes a water storage tank (1), a stilling basin (2), and multiple experimental pipes (3) connected in parallel. The inlet and outlet of each experimental pipe (3) are connected to the water storage tank (1) and the stilling basin (2), respectively. Each experimental pipe (3) has different morphological parameters. S2. Select the target test pipe: Determine the shape of the variable cross-section flood discharge tunnel to be tested, select the corresponding target test pipe (3), and keep the inlet and outlet ends of the target test pipe (3) connected to the water storage tank (1) and the stilling tank (2) respectively, while closing the inlet ends of the other non-target test pipes (3). S3. Run the experiment and measure the data: Water is supplied to the reservoir (1), and the water flows into the stilling basin (2) through the target experimental pipe (3); during this period, the flow velocity, pressure and water level in the target experimental pipe (3) are measured. S4. Switching and repeating the experiment: When it is necessary to test another type of variable cross-section flood discharge tunnel, close the inlet end of the current target experimental pipe (3) and repeat steps S2 and S3; continuously select new target experimental pipes (3) for testing, and complete the experiment when all experimental pipes (3) have been tested.

2. The method for measuring flow in a variable cross-section spillway tunnel according to claim 1, characterized in that: In step S3, water is supplied to the reservoir (1) by a circulating water pump (18). The input end of the circulating water pump (18) is connected to the stilling basin (2) through a pipe, and the output end is connected to the reservoir (1) through a pipe. An electromagnetic flow meter (19) is installed on the pipe connecting the circulating water pump (18) to the reservoir (1).

3. The method for measuring flow in a variable cross-section spillway tunnel according to claim 2, characterized in that: The water storage tank (1) is equipped with a water stabilizing device, which includes a water stabilizing pipe (20) and a water stabilizing filter pad (21). The water stabilizing pipe (20) is connected to a pipe connected to the output end of the circulating water pump (18). The outer circumferential surface of the water stabilizing pipe (20) is provided with multiple water passage holes (22), and the water stabilizing filter pad (21) covers the water stabilizing pipe (20).

4. The method for measuring flow in a variable cross-section spillway tunnel according to claim 1, characterized in that: The experimental pipe (3) has multiple detection holes (4) distributed along its own length at the top. The detection holes (4) are equipped with a flow meter (5) for measuring the flow velocity of water and a water level gauge (6) for measuring the water level height.

5. The method for measuring flow in a variable cross-section spillway tunnel according to claim 4, characterized in that: The experimental pipe (3) includes a contraction section (301), a transition section (302), a gradual section (303), and a stable section (304) arranged sequentially from the direction close to the water storage tank (1) to the direction away from the water storage tank (1). The stable section (304) of each experimental pipe (3) has the same length, and the detection hole (4) is opened in the stable section (304).

6. The method for measuring flow in a variable cross-section spillway tunnel according to claim 1, characterized in that: The water storage tank (1) is provided with outlets (7) corresponding to each experimental pipe (3). The inlet end of each target experimental pipe (3) is connected to each outlet (7). The water storage tank (1) is provided with a blocking assembly, which includes an mounting plate (8) and a blocking plate (9). The mounting plate (8) is installed on the water storage tank (1). Multiple blocking plates (9) are provided corresponding to each outlet (7). Each blocking plate (9) slides vertically and is fitted to the mounting plate (8). Each blocking plate (9) is used to open and close each outlet (7).

7. The method for measuring flow in a variable cross-section spillway tunnel according to claim 6, characterized in that: The mounting plate (8) is provided with a return spring (10) corresponding to the blocking plate (9). In normal condition, the blocking plate (9) opens the outlet (7) under the elastic force of the return spring (10). The blocking plate (9) is provided with a wedge-shaped locking block (11) and a locking spring (12). The bottom of the wedge-shaped locking block (11) is a wedge-shaped surface (111). A locking groove (13) is provided on one side of the blocking plate (9). The wedge-shaped locking block (11) slides and engages with the locking groove (13). A spring (12) is provided in the locking groove (13) and applies a spring force to the wedge-shaped locking block (11) to move away from the blocking plate (9); the mounting plate (8) has a locking hole (14) that corresponds to the wedge-shaped locking block (11) and is inserted into the wedge-shaped locking block (11); when the wedge-shaped locking block (11) is inserted into the locking hole (14), the blocking plate (9) closes the outlet (7); an unlocking component is provided in the locking hole (14) to push the wedge-shaped locking block (11) out of the locking hole (14).

8. The method for measuring flow in a variable cross-section spillway tunnel according to claim 7, characterized in that: The unlocking assembly includes an unlocking block (15) and an unlocking spring (16). One end of the unlocking block (15) is located inside the locking hole (14), and the other end passes through and slides into the mounting plate (8). The unlocking spring (16) is located inside the locking hole (14) and applies a spring force to the unlocking block to move away from the blocking plate (9).

9. The method for measuring flow in a variable cross-section spillway tunnel according to claim 1, characterized in that: Each of the experimental pipes (3) has multiple pressure measuring holes distributed along its own length at the bottom, and each pressure measuring hole is connected to a pressure measuring pipe (23); a pressure bar is provided on one side of the water storage tank (1), and the pressure bar includes pressure measuring cylinders (24) that are arranged one-to-one with the pressure measuring holes, and each pressure measuring cylinder (24) is connected to a connecting pipe (25).

10. The method for measuring flow in a variable cross-section spillway tunnel according to claim 9, characterized in that: The pressure testing pipe (23) is provided with a male connector (26), and the connecting pipe (25) is provided with a female connector (27) corresponding to the male connector (26). When the connecting pipe is connected to the female connector (27), the pressure testing pipe (23) and the connecting pipe (25) are connected.

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