Sluice weir crest and design method thereof

Abstract

The invention relates to a flood discharge gate weir crest and a design method thereof.The design method comprises the steps that S1, a flood discharge gate single-hole mathematical model is established, the boundary condition and the initial water flow condition of the mathematical model are determined, and numerical simulation calculation is conducted; s2, changing the length of the weir crest of the flood discharge gate, and respectively carrying out numerical simulation calculation; s3, according to the calculation result of the S2, the optimal range of the lengthening length of the weir crest is determined by taking the first risk value k1 of the impact trunnion as a judgment condition; and S4, establishing a flood discharge gate single-hole physical model, performing a physical model test on the schemes in the optimal range of the weir crest lengthening length determined in the S3, and determining the optimal scheme of the weir crest lengthening length by taking the second risk value k2 of the impact trunnion as a judgment condition. According to the method, firstly, a flood discharge gate single-hole mathematical model is established, an optimal scheme is preliminarily determined, the model modification frequency, consumables and cost of a physical model are reduced, then the optimal scheme of the length of the weir crest of the flood discharge gate is finally determined through a physical model test, and the risk that water spray on the surface layer of a nappe impacts a gate trunnion is reduced.

Description

Technical Field

[0001] The invention relates to the field of flood discharge, and in particular to a flood discharge gate weir crest and a design method thereof. Background Art

[0002] Flood discharge gates are working gates used to discharge flood water and regulate and control the water level of reservoirs. They can release excess water when the water level is too high to ensure the safety of reservoirs or rivers, effectively prevent floods, and avoid disasters causing significant losses to people's lives and property. At the same time, flood discharge gates can also regulate water levels, maintain the stability of water sources and the cleanliness of water quality, and improve production efficiency and agricultural production capacity.

[0003] The flood discharge of low-head riverbed hub is large, and the flooding degree below the gate is large. Water jump may occur in the steep slope section of the gate chamber, and the jump head is close to the gate hinge. The water splash on the surface of the water tongue has the risk of impacting the gate hinge, which may be detrimental to the stability of the hinge structure.

[0004] The weir crest length of a flood gate refers to the length of the top of the flood gate (i.e. the weir crest) along the direction of water flow. The weir crest length has an important impact on the discharge capacity, water flow stability and structural safety of the flood gate. The weir crest length of a flood gate directly affects the state of water flow when it passes through. A longer weir crest helps the water flow transition more smoothly, reduces the jumping and splashing of the water tongue, and thus reduces the risk of the surface water splash of the water tongue impacting the gate hinge. A shorter weir crest may cause a sharp change in the water flow, increase the kinetic energy and impact force of the water tongue, and make it easier for the surface water splash of the water tongue to impact the gate hinge.

[0005] In summary, there is a correlation between the crest length of the flood gate and the risk of the water splash on the surface of the water tongue impacting the gate hinge. When designing a flood gate, it is necessary to consider multiple factors to determine the appropriate crest length and take effective measures to reduce the risk of the water splash on the surface of the water tongue impacting the gate hinge. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a flood discharge gate crest and a design method thereof.

[0007] In a first aspect, the present invention provides a method for designing a flood discharge gate crest, comprising the following steps:

[0008] S1: Establish a mathematical model of a single hole of the flood discharge gate, determine the boundary conditions of the mathematical model and the initial water flow conditions, and perform numerical simulation calculations;

[0009] S2: Change the length of the flood discharge gate crest and perform numerical simulation calculations respectively;

[0010] S3: According to the calculation result of S2, the first risk value k1 of impacting the support hinge is used as a judgment condition to determine the optimal range of the weir crest extension length;

[0011] S4: Establish a physical model of a single hole of the flood discharge gate, conduct physical model tests on the schemes within the optimal range of the weir crest extension length determined in S3, and determine the optimal scheme for extending the weir crest length using the second risk value k2 of the impact support hinge as the judgment condition.

[0012] The present invention provides a flood discharge gate weir crest and a design method thereof. Firstly, a single-hole mathematical model of the flood discharge gate is established to study the law of water jump change, so as to quickly grasp the improvement effect of optimization measures, preliminarily determine a better solution, reduce the number of model modifications of the physical model, and reduce the consumables and cost of the physical model. Then, the better solution determined by the mathematical model is further confirmed through a physical model test, and finally the optimal solution for the flood discharge gate weir crest length is determined, thereby reducing the risk of water splashes on the surface of the water tongue impacting the gate support hinge.

[0013] Preferably, in S1, the upstream boundary adopts the water level boundary, and the downstream boundary adopts the water level boundary.

[0014] Preferably, in S2, the length of the flood discharge gate crest varies within a range of 0.5m-10m.

[0015] Preferably, in S2, the length of the flood discharge gate crest changes linearly, and the increment of change is 0.1m-0.5m.

[0016] Preferably, in S3, the expression of the first risk value k1 of impacting the support hinge is as follows:

[0017] k1 = f (water jump head position, jump head water depth, maximum bottom flow velocity of the lock chamber, discharge flow, lock chamber water surface line);

[0018] Where f is a function.

[0019] Preferably, in S3, the expression of the first risk value k1 of impacting the support hinge is as follows:

[0020] k1 = n1f1 (water jump head position) + n2f2 (jump head water depth) + n3f3 (maximum bottom flow velocity of the lock chamber)

[0021] +n4f4(discharge flow)+n5f5(water surface line of lock chamber);

[0022] In the formula, f1, f2, f3, f4, and f5 are functions respectively, n1, n2, n3, n4, and n5 are coefficients respectively, and n1+n2+n3+n4+n5=1.

[0023] Preferably, in S3, n1≥n2>n3≥n4≥n5.

[0024] Preferably, in said S4, when establishing the physical model of a single hole of the flood discharge gate, the flow structure and the downstream seafloor section are made of organic glass.

[0025] Preferably, in S4, the expression of the second risk value k2 of impacting the support hinge is as follows:

[0026] k2 = g (water jump head position, lock chamber water surface line, weir surface pressure);

[0027] Where g is a function.

[0028] Preferably, in S4, the expression of the second risk value k2 of impacting the support hinge is as follows:

[0029] k2=m1g1(water jump head position)+m2g2(lock chamber water surface line)+m3g3(weir surface pressure)

[0030] Wherein, g1, g2, g3 are functions, m1, m2, m3 are coefficients, and m1+m2+m3=1.

[0031] Preferably, in S4, m1≥m2≥m3.

[0032] In a second aspect, the present invention provides a flood discharge gate designed using any of the above-mentioned methods for designing a flood discharge gate weir crest.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention provides a flood discharge gate weir crest and a design method thereof. Firstly, a single-hole mathematical model of the flood discharge gate is established to study the law of water jump change, so as to quickly grasp the improvement effect of optimization measures, preliminarily determine a better solution, reduce the number of model modifications of the physical model, and reduce the consumables and cost of the physical model. Then, the better solution determined by the mathematical model is further confirmed through a physical model test, and finally the optimal solution for the flood discharge gate weir crest length is determined, thereby reducing the risk of water splashes on the surface of the water tongue impacting the gate support hinge.

[0035] The present invention can preliminarily determine a better solution based on the mathematical model by combining mathematical simulation calculations and physical model tests, and then further confirm the better solution determined by the mathematical model through physical model tests, and finally determine the optimal solution for the length of the flood discharge gate crest, which can greatly reduce the number of model modifications of the physical model, reduce the consumables and costs of the physical model, and improve the efficiency of the physical model test. Moreover, through the dual verification of mathematical simulation calculations and physical model tests, the feasibility and accuracy of the optimization plan can be further guaranteed. The optimized flood discharge gate crest can effectively reduce the risk of water splashes on the surface of the water tongue impacting the gate support hinge, and ensure the safe operation of the hub flood discharge gate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the floor plan of the discharge structure.

[0037] Figure 2This is the longitudinal section of the flood discharge gate.

[0038] Figure 3 This is a schematic diagram showing the risk of water splashing on the surface of the water tongue impacting the gate hinges.

[0039] Figure 4 Schematic diagram of the mathematical model of a single hole of a flood discharge gate.

[0040] Figure 5 This is the boundary condition diagram of the mathematical model of the flood discharge gate.

[0041] Figure 6 This is the cross-sectional layout of the wide crest weir of the flood discharge gate.

[0042] Figure 7 Schematic diagram of the flow field in the flood discharge gate chamber.

[0043] Figure 8 This is the water surface line along the weir crest extension plan.

[0044] Fig. 9 The body parameter diagram of the weir crest extension scheme recommended for numerical simulation.

[0045] Fig.10 This is a schematic diagram of the scope of the hydraulic physical model.

[0046] Fig.11 This is the overall layout diagram of the hydraulic physical model.

[0047] Fig.12 This is the layout diagram of the floodgate in the hydraulic physics model.

[0048] Fig.13 This is a comparison chart of the hydraulic jump positions in the lock chamber.

[0049] Fig.14 This is a comparison chart of the water surface line in the lock chamber.

[0050] Fig.15 This is a comparison chart of the pressure on the lock chamber weir surface. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0052] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0053] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0054] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely descriptions used to distinguish the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0055] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0056] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0057] Example 1

[0058] The main layout of the water discharge structure of a hub is 7 flood discharge gates and 1 bottom discharge hole. The dam is 122m long and the dam top elevation is 17.50m. The plan layout and longitudinal section of the water discharge structure are shown in Figure 1-2 shown.

[0059] The 7-hole flood discharge gate is arranged in the main river channel, with a single hole net width of 13.0m and a total front width of 116.0m. The gate pier is split, with the left pier thickness of 2.0m, the middle pier thickness of 3.5m, and the right pier thickness of 2.0m. The width of a single hole is 16.50m. The flood discharge gate top elevation is 17.50m, the weir top elevation is 1.00m, and the gate chamber length along the water flow direction is 35.0m. From upstream to downstream, a flat inspection door and an arc-shaped working door are set in sequence. The inspection door is opened and closed by a mobile gantry crane on the dam top, and the working door is opened and closed by a hydraulic hoist. A 4.8m wide traffic bridge is set on the upstream side of the gate top, and the traffic bridge top elevation is 17.50m. Two gate top gantry track beams are arranged next to the traffic bridge, and oil pipe cable box beams are arranged on the downstream side. The flood discharge gate weir type adopts a wide top weir, and the weir top elevation is 1.00m. Behind the flood discharge gate, it is connected to the seafloor through a 1:4 slope. The seafloor is 100m long and a riprap anti-scour trough is set at the end.

[0060] The hub is a low-head riverbed hub with a large flood discharge and a large flood depth below the gate. Under the verification condition, the water jump occurs in the steep slope section of the gate chamber, and the jump head is close to the gate hinge. The water splash on the surface of the water tongue has the risk of impacting the gate hinge, which may be detrimental to the stability of the hinge structure. Figure 3 shown.

[0061] Consider optimizing the lock chamber structure and push the hydraulic jump location downstream, thereby reducing the water depth at the hinge location.

[0062] A method for designing a flood discharge gate crest comprises the following steps:

[0063] S1: Establish a mathematical model of a single hole of the flood discharge gate, determine the boundary conditions of the mathematical model and the initial water flow conditions, and perform numerical simulation calculations.

[0064] The mathematical model of a single hole of a flood discharge gate is as follows Figure 4 The model study range is from 10m above the dam to 120m below the dam. The upstream boundary uses the water level boundary and the water level is set to 15.17m. The downstream boundary uses the water level boundary and the water level is set to 11.74m. The mathematical model boundary conditions and initial water flow conditions are set in Figure 5 .

[0065] S2: Change the length of the flood discharge gate crest and perform numerical simulation calculations to study the law of hydraulic jump changes and quickly grasp the improvement effect of optimization measures.

[0066] When changing the length of the flood discharge gate weir crest, the variation range of the flood discharge gate weir crest length can be 0.5m-10m, that is, the flood discharge gate weir crest length can be increased by 0.5m to about 10m, and mathematical simulation calculations are performed in sequence.

[0067] Furthermore, when changing the length of the flood gate crest, the flood gate crest length can be linearly changed or nonlinearly changed, and usually the change increment of the flood gate crest length is 0.1m-0.5m. For example, taking 0.5m as a change increment, the increase values ​​of the flood gate crest length are: 0.5m, 1m, 1.5m, 2m... It can also be a nonlinear change, for example, the increase values ​​of the flood gate crest length are: 1m, 2m and 5m, etc.

[0068] Considering the lengthening of the straight section of the weir crest (elevation 1.00m), the cross-section of the wide crest weir of the flood discharge gate is arranged as follows: Figure 6 The calculation conditions and statistical results are shown in Table 1. The longitudinal flow field results under each scheme are shown in Figure 7 As shown, the water surface line along the way is as follows Figure 8 According to the calculation results, the flow rate will be slightly reduced if the length of the straight section of the weir top is lengthened, and the flow rate will be reduced by about 0.5% if the length is increased by 5m.

[0069] When lengthened by 1m and 2m, the head of the water jump moves down by about 1.5m and 3.0m respectively, and the water depth of the contraction section does not change much; when lengthened by 5m, although the head of the water jump moves down, the water depth of the contraction section increases significantly. According to the flow field distribution diagram, the risk of impacting the support hinge is further increased.

[0070] Table 1 Calculation conditions and statistical results of the weir crest extension scheme

[0071]

[0072] S3: According to the calculation results of S2, it can be seen that the longer the length of the weir crest is, the better it is. The first risk value k1 of the impact support hinge is used as the judgment condition to determine the optimal range of the weir crest lengthening length.

[0073] In S3, the expression of the first risk value k1 of impacting the support hinge can be as follows:

[0074] k1 = f (water jump head position, jump head water depth, maximum bottom flow velocity of the lock chamber, discharge flow, lock chamber water surface line);

[0075] Where f is a function.

[0076] When calculating the first risk value k1 of impacting the support hinge, it is necessary to first identify the influencing factors that affect the risk of impacting the support hinge. Through research and analysis, it is determined that the first risk value k1 of impacting the support hinge is highly correlated with the water jump head position, jump head water depth, maximum bottom flow velocity of the lock chamber, discharge flow, and lock chamber water surface line, that is, the water jump head position, jump head water depth, maximum bottom flow velocity of the lock chamber, discharge flow, and lock chamber water surface line are influencing factors.

[0077] Furthermore, in S3, the expression of the first risk value k1 of impacting the support hinge can be as follows:

[0078] k1 = n1f1 (water jump head position) + n2f2 (jump head water depth) + n3f3 (maximum bottom flow velocity of the lock chamber)

[0079] +n4f4(discharge flow)+n5f5(water surface line of lock chamber);

[0080] In the formula, f1, f2, f3, f4, and f5 are functions, n1, n2, n3, n4, and n5 are coefficients, and n1+n2+n3+n4+n5=1. n1, n2, n3, n4, and n5 represent the importance of different influencing factors. The values ​​of n1, n2, n3, n4, and n5 can be different, and the larger the value, the more important it is.

[0081] In the calculation of the risk of impacting the support hinge, the most important influencing factor is identified and assigned the largest coefficient. By setting different importance levels, the first risk value k1 of the impacting the support hinge can be obtained more accurately.

[0082] Furthermore, n1≥n2>n3≥n4≥n5. That is, the influence and importance of the water jump head position and the water depth of the jump head are usually greater than the influence and importance of the maximum bottom flow velocity, discharge flow and water surface line of the lock chamber.

[0083] According to the numerical simulation results of lengthening by 1m, 2m and 5m, it is recommended that the schemes of lengthening by 1m and 2m are the better options, that is, lengthening by 1-2m is the better range of the length of the weir crest.

[0084] S4: Establish a physical model of a single hole of the flood discharge gate, conduct physical model tests on the schemes within the optimal range of the weir crest extension length determined in S3, and determine the optimal scheme for extending the weir crest length using the second risk value k2 of the impact support hinge as the judgment condition.

[0085] According to the preliminary optimization results of the numerical model, the physical model was tested for the recommended solution (1m and 2m extension of the weir crest). Fig. 9 shown.

[0086] When establishing a single-hole physical model of a flood discharge gate, follow these steps:

[0087] Model scale:

[0088] The normal model is used for hydraulic simulation of the water discharge structure. According to the experimental research content, the model scale is set to 40, and the geometric similarity, velocity similarity, resistance similarity and flow similarity are required.

[0089] In addition, the model should also satisfy (1) the model water flow must be turbulent, that is, the model Reynolds number ≥ 1000.

[0090] Where, V is the flow velocity (m / s); R is the hydraulic radius (m); v is the viscosity coefficient of water flow.

[0091] (2) Minimum water depth restriction: To avoid the influence of surface tension, the minimum water depth of the model test section should not be less than 0.03 m.

[0092] Model range:

[0093] According to the topographic data of the hub river section, and considering the similarity of the flow conditions of the model inlet and outlet, the flow pattern in the test section is guaranteed not to be affected. The research scope of the physical model is 510m upstream of the dam site to 650m downstream of the dam site, and the length of the simulated river section is about 1.16km. Fig.10 .

[0094] Model making:

[0095] The model is supplied with water by the water supply system. A flat water section and a water stabilizing fence are set up upstream to ensure the smooth flow of water in the reservoir area. The reservoir area and the downstream river channel are simulated according to the actual terrain. The terrain modeling adopts the cross-section method. The model section is scaled down according to the plane scale and vertical scale based on the measured riverbed terrain. The model section is made of five layers of plates and is set up by the arranged main control. The cross-section elevation control error is less than ±1.0mm, the plane control error is less than ±1.0cm, and the terrain surface is plastered with cement mortar. The flood discharge gate, bottom hole, power station and other flow structures and the downstream sea section are made of plexiglass to facilitate flow field observation and parameter measurement. The simulated river section is all lined with concrete. The prototype roughness is 0.012~0.014, and the model roughness is required to be 0.006~0.008. The cement mortar plastering and plexiglass can meet the roughness requirements. The model site layout is shown in Figure 11-12.

[0096] Measurement and control equipment:

[0097] The main measurement and control instruments and equipment for model tests include:

[0098] Flow rate: Siemens electromagnetic flowmeter is used for control and measurement.

[0099] Tailgate water level: controlled and adjusted by a flap-type tailgate with fine-tuning function.

[0100] Water level along the route: measured using a water level probe.

[0101] Time-averaged pressure: measured using a pressure gauge.

[0102] Pulsating pressure: measured by a resistive pulsating pressure sensor.

[0103] Flow velocity: measured using a new Norwegian-made acoustic Doppler three-dimensional point flow meter and a propeller flow meter.

[0104] After the physical model of the single hole of the spillway was established, the three typical characteristic water levels of verification (P = 0.1%), design (P = 1%), and energy dissipation and anti-scouring (P = 2%) were selected for testing, taking into account the flood control conditions of the hub and the energy dissipation and anti-scouring conditions of the downstream sea floodplain and riverbed, as shown in Table 2. The flow pattern, water surface line along the way, bottom flow velocity along the way, time-averaged pressure of the bottom plate of the spillway, and pulsating pressure of the bottom plate of the downstream sea floodplain section were tested at each level of flow. The water level boundary control positions above and below the dam of the model are 400m above the dam and 600m below the dam, respectively, and the water level is controlled according to Table 2.

[0105] Table 2 Flood discharge gate test conditions

[0106]

[0107] The water jump head position after the weir crest was lengthened, the water surface line of the lock chamber and the pressure distribution on the weir surface were tested under the specified working conditions. The specific results are as follows.

[0108] (1) Water jump first position

[0109] The hydraulic jump of the lock chamber under the original design and the weir crest extension (1m, 2m) scheme is shown in Figure 2. Fig.13 It can be seen that the position of the water jump is significantly lowered after the weir crest is lengthened. When the weir crest is lengthened by 1m, the water jump is at 0+035.56m below the dam, which is 1m lower than the original design. When the weir crest is lengthened by 2m, the water jump is at 0+037.46m below the dam, which is 2.9m lower than the original design. Under the weir crest lengthening scheme, the risk of water tongue impacting the gate hinge is eliminated.

[0110] (2) Water surface line and pressure

[0111] The water surface line of the lock chamber and the pressure distribution of the weir surface (along the center line of No. 4 flood discharge gate) under the original design scheme and the weir top extension (1m, 2m) scheme are shown in Fig.14 , Fig.15 Corresponding to the flow pattern diagram, under the weir crest extension scheme, the water surface line at the weir crest is slightly raised, and the water jump position moves down. At 100m below the dam, the water surface lines of the original design scheme and the weir crest extension scheme are basically consistent. The weir surface pressure is positive pressure.

[0112] Specifically, in S4, the expression of the second risk value k2 of impacting the support hinge is as follows:

[0113] k2 = g (water jump head position, lock chamber water surface line, weir surface pressure);

[0114] Where g is a function.

[0115] When calculating the second risk value k2 of impacting the hinge, the influencing factors that affect the risk of impacting the hinge must be identified first. The numerical simulation results show that the water jump position and the water surface line of the lock chamber have a greater impact on the risk of impacting the hinge. Therefore, the water jump position and the water surface line of the lock chamber are selected as the influencing factors of the second risk value k2 of impacting the hinge, and the weir surface pressure is added as an influencing factor. It can be seen that the selection of influencing factors that affect the risk of impacting the hinge can be further optimized through the numerical simulation results. For example, the water jump position and the water surface line of the lock chamber are selected as the influencing factors of the second risk value k2 of impacting the hinge, while the water depth of the lock head, the maximum bottom flow velocity of the lock chamber, and the discharge flow are no longer used as influencing factors, thereby further optimizing the calculation expression of the second risk value k2, so as to obtain more accurate risk assessment results.

[0116] In S4, the expression of the second risk value k2 of impacting the support hinge can be as follows:

[0117] k2=m1g1(water jump head position)+m2g2(lock chamber water surface line)+m3g3(weir surface pressure)

[0118] In the formula, g1, g2, g3 are functions, m1, m2, m3 are coefficients, and m1+m2+m3=1. The values ​​of m1, m2, m3 can be different, and the larger the value, the more important it is.

[0119] In the calculation of the risk of impacting the support hinge, the most important influencing factor is identified and assigned the largest coefficient. By setting different importance levels, the second risk value k2 of the impacting the support hinge can be obtained more accurately.

[0120] Furthermore, m1≥m2≥m3. That is, usually the influence and importance of the water jump head position is greater than the influence and importance of the lock chamber water surface line, and the influence and importance of the lock chamber water surface line is greater than the influence and importance of the weir surface pressure.

[0121] For example, in this embodiment, in the recommended schemes determined by numerical simulation (schemes with the weir top extended by 1m and 2m), since the position of the water jump head in the scheme with the weir top extended by 2m is farther away from the support, and the water surface line is basically consistent with the original design scheme, the weir surface pressure is positive pressure, which further determines that extending the weir top by 2m is the optimal scheme.

[0122] The present invention provides a design method for the crest of a flood discharge gate. First, a mathematical model of a single hole of the flood discharge gate is established to study the law of hydraulic jump changes, so that the improvement effect of optimization measures can be quickly grasped, and a more optimal solution can be preliminarily determined, thereby reducing the number of model modifications of the physical model. For example, in this embodiment, the physical model is only modified twice (the crest of the weir is lengthened by 1m and 2m), reducing the consumables and costs of the physical model and improving the efficiency of the physical model test. Then, the more optimal solution determined by the mathematical model is further confirmed through the physical model test, and finally the optimal solution for the crest length of the flood discharge gate is determined.

[0123] The present invention can preliminarily determine a better solution based on the mathematical model by combining mathematical simulation calculations and physical model tests, and then further confirm the better solution determined by the mathematical model through physical model tests, and finally determine the optimal solution for the length of the flood discharge gate crest, which can greatly reduce the number of model modifications of the physical model, reduce the consumables and costs of the physical model, and improve the efficiency of the physical model test. Moreover, through the dual verification of mathematical simulation calculations and physical model tests, the feasibility and accuracy of the optimization plan can be further guaranteed. The optimized flood discharge gate crest can effectively reduce the risk of water splashes on the surface of the water tongue impacting the gate support hinge, and ensure the safe operation of the hub flood discharge gate.

[0124] Example 2

[0125] A flood discharge gate is designed using the design method for a flood discharge gate weir crest as described in Example 1.

[0126] The flood discharge gate described in the present invention is designed using the design method of Example 1. By optimizing the length of the flood discharge gate weir top, the risk of water splashes on the surface of the water tongue impacting the gate hinge can be effectively reduced, thereby ensuring the safe operation of the hub flood discharge gate.

[0127] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A design method for a flood discharge gate crest, characterized in that: The following steps are involved: S1: Establish a mathematical model of a single hole of the flood discharge gate, determine the boundary conditions of the mathematical model and the initial water flow conditions, and perform numerical simulation calculations; S2: Change the length of the flood discharge gate crest and perform numerical simulation calculations respectively; S3: According to the calculation result of S2, the first risk value k1 of impacting the support hinge is used as a judgment condition to determine the optimal range of the weir crest extension length; S4: Establish a physical model of a single hole of the flood discharge gate, conduct physical model tests on the schemes within the optimal range of the weir crest extension length determined in S3, and determine the optimal scheme for extending the weir crest length using the second risk value k2 of the impact support hinge as the judgment condition.

2. A method for designing a flood discharge gate crest according to claim 1, characterized in that: In S1, the upstream boundary adopts the water level boundary, and the downstream boundary adopts the water level boundary.

3. The design method of a flood discharge gate crest according to claim 1, characterized in that: In S2, the length of the flood discharge gate crest varies between 0.5m and 10m.

4. The design method of a flood discharge gate crest according to claim 1, characterized in that: In S2, the length of the flood discharge gate crest changes linearly, and the increment of change is 0.1m-0.5m.

5. The design method of a flood discharge gate crest according to claim 1, characterized in that: In S3, the expression of the first risk value k1 of impacting the support hinge is as follows: k1 = f (water jump head position, jump head water depth, maximum bottom flow velocity of the lock chamber, discharge flow, lock chamber water surface line); Where f is a function.

6. A method for designing a flood discharge gate crest according to claim 1, characterized in that: In S3, the expression of the first risk value k1 of impacting the support hinge is as follows: k1 = n1f1 (water jump head position) + n2f2 (jump head water depth) + n3f3 (maximum bottom flow velocity of the lock chamber) +n4f4(discharge flow)+n5f5(water surface line of lock chamber); In the formula, f1, f2, f3, f4, and f5 are functions respectively, n1, n2, n3, n4, and n5 are coefficients respectively, and n1+n2+n3+n4+n5=1.

7. A method for designing a flood discharge gate crest according to claim 6, characterized in that: In S3, n1≥n2>n3≥n4≥n5.

8. The design method of a flood discharge gate crest according to claim 1, characterized in that: In said S4, when establishing the physical model of a single hole of the flood discharge gate, the flow structure and the downstream seafloor section are made of organic glass.

9. The method for designing a flood discharge gate crest according to claim 1, characterized in that: In S4, the expression of the second risk value k2 of impacting the support hinge is as follows: k2 = g (water jump head position, lock chamber water surface line, weir surface pressure); Where g is a function.

10. A method for designing a flood discharge gate crest according to claim 1, characterized in that: In S4, the expression of the second risk value k2 of impacting the support hinge is as follows: k2=m1g1(water jump head position)+m2g2(lock chamber water surface line)+m3g3(weir surface pressure) Wherein, g1, g2, g3 are functions, m1, m2, m3 are coefficients, and m1+m2+m3=1.

11. A method for designing a flood discharge gate crest according to claim 10, characterized in that: In S4, m1≥m2≥m3.

12. A flood discharge gate, characterized in that: The invention is designed by adopting the design method of a flood discharge gate crest as described in any one of claims 1 to 11.

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