A water conservancy and hydropower sand flushing system

Abstract

The present invention discloses a water conservancy and hydropower sand flushing system, which relates to the field of water conservancy and hydropower engineering. It includes a main dam body, a sand retaining dam, a stone retaining dam, a water inlet culvert for the generator set, a sand discharge gate, an arc-shaped base, a water level monitoring module and a control module; the stone retaining dam intercepts large-diameter stones in front, the arc-shaped base realizes water-sand separation, the sand discharge gate is provided with upper and lower layers of water outlets, and the energy is dissipated by the collision of jet flows; the control module combines an adaptive PID closed-loop control model, adjusts the opening of the sand retaining dam gate according to the water level monitoring data, maintains the stability of the water level in the middle reservoir area, and realizes the linkage switching between the power generation and sand discharge working conditions. The present invention solves the pain points of the existing system such as poor water-sand separation, unstable energy dissipation, and lagging water level control, can intercept stones in front, efficiently separate sand, stably dissipate energy, improve the stability and practicability of the system, reduce the maintenance cost, and is suitable for water conservancy and hydropower projects in multi-sand rivers.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower technology, specifically to a water conservancy and hydropower sand flushing system. Background Technology

[0002] In water conservancy and hydropower projects, the sediment flushing system is a core supporting facility for ensuring the long-term stable operation of reservoirs and hydropower stations. Its main function is to remove silt accumulated in the reservoir area, preventing silt from clogging the power generation channels and eroding the generator blades, while reducing the scouring of the downstream riverbed by the silt discharge flow, thus balancing power generation efficiency and project safety. The problem of siltation is particularly prominent in water conservancy and hydropower projects on sediment-rich rivers. The severe interannual fluctuations in runoff and the high concentration of water and sediment during the flood season further exacerbate the operational pressure on the sediment flushing system. Existing sediment flushing systems are no longer sufficient to meet the actual needs of the projects and have several technical challenges, as detailed below:

[0003] First, existing sand flushing systems suffer from poor water-separation performance, leading to interference between power generation and sand discharge. Traditional sand flushing systems often employ direct sand discharge upstream of the dam without dedicated water-separation structures, resulting in mixing of power generation and sand discharge flows. High-sand-laden water easily enters the generator intake culvert, causing turbine blade erosion, reduced efficiency, and shortened lifespan. Some systems with sand-trapping structures lack reasonable sediment collection designs, leading to uniform sediment accumulation at the bottom of the reservoir, failing to meet the core requirement of "clear water power generation and sediment removal." Furthermore, frequent shutdowns for maintenance during sand discharge severely impact power generation efficiency. Simultaneously, existing projects often employ a "clear water storage and turbid water discharge" approach, storing water for water use during non-flood seasons and lowering water levels for sand discharge during flood seasons. While this maintains effective reservoir capacity to some extent, the insufficient sediment control capacity during flood season results in forced water release for sand discharge in wet years and difficulty in ensuring downstream ecological base flow during dry years.

[0004] Secondly, the energy dissipation effect of sediment flushing is unstable, easily causing scouring and damage to the downstream riverbed. Existing sediment flushing systems mostly use a single outlet design for their gates. The high-speed, sediment-laden water flow has a large impact force, directly scouring the downstream riverbed, leading to riverbed erosion, bank instability, and affecting the river's ecological balance. While some systems employ layered energy dissipation structures, they fail to address the problem of "water level drop during sediment flushing causing deviation of the energy dissipation jet and attenuation of the energy dissipation effect," resulting in poor energy dissipation reliability and an inability to effectively counteract the impact force of high-speed water flow. Furthermore, some projects use ultra-deep and ultra-large sediment flushing bottom holes to improve sediment flushing capacity, but these designs are complex, costly to construct, and unsuitable for small and medium-sized water conservancy and hydropower projects, making widespread adoption difficult.

[0005] Secondly, the coordination between water level control and energy dissipation / sediment removal is poor, resulting in insufficient system stability. Fluctuations in the upstream water level directly alter the flow velocity and water level in the intermediate reservoir, thereby affecting sediment deposition, sediment removal capacity, and energy dissipation. However, in existing technologies, the gates of sediment-trapping dams are mostly manually controlled or use simple on / off control modes, which cannot adaptively adjust the gate opening based on real-time changes in the upstream natural water level and the water level in the intermediate reservoir. This leads to excessive fluctuations in the water level in the intermediate reservoir, preventing the jets from the double-layer outlets from converging precisely, significantly reducing the energy dissipation effect, and even causing problems such as blockage of the sediment removal channel and turbulent water flow.

[0006] Finally, existing sand flushing systems largely fail to address the interception of large-diameter stones, further exacerbating the risks of equipment damage and channel blockage. Sandy rivers often contain large pebbles and rocks, and existing sand flushing systems lack dedicated rock-catching structures. Large-diameter stones, once carried into the reservoir by the water flow, easily collide with structures such as sand-catching dams and arched bases, causing component damage. They also easily clog discharge gates and channels, leading to system malfunctions, increased maintenance costs, and safety hazards. While some dredging technologies can address riverbed siltation, they require large dredgers and high-pressure deep-water pumps, resulting in high power consumption, complex construction, and unsuitability for routine sand flushing operations in reservoir areas.

[0007] In summary, current hydropower sediment flushing systems suffer from several technical challenges, including poor water-sediment separation, unstable sediment discharge and energy dissipation, insufficient coordination between water level control and operating conditions, and susceptibility to interference from large-diameter stones. These issues lead to low system efficiency, high maintenance costs, and short equipment lifespans, making it difficult to simultaneously meet the dual demands of power generation and sediment flushing, and failing to satisfy the long-term stable operation requirements of hydropower projects on sediment-laden rivers. Therefore, developing a hydropower sediment flushing system that achieves efficient water-sediment separation, stable energy dissipation, adaptive water level control, and coordinated power generation and sediment discharge operations has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0008] In order to solve the technical problems existing in the prior art, this application provides a water conservancy and hydropower sand flushing system.

[0009] To achieve the above objectives, the technical solution adopted in this application is: a water conservancy and hydropower sand flushing system, comprising:

[0010] The main dam body has a generator set water intake culvert in the middle of the main dam body, and sand discharge channels on both sides of the main dam body, with sand discharge gates installed on the sand discharge channels;

[0011] A sediment trap is located upstream of the main dam body, forming an intermediate reservoir between the main dam body and the sediment trap. An arc-shaped base is provided at the bottom of the intermediate reservoir, and the arc-shaped base has a curved surface structure that is high in the middle and low on both sides. Sedimentation troughs are formed on both sides of the arc-shaped base, and the bottom of the sedimentation troughs slopes towards the sediment discharge gate. The positions of the sedimentation troughs correspond one-to-one with the positions of the sediment discharge gates. An adjustable bottom gate is provided on the sediment trap, and an overflow outlet is provided at the top of the sediment trap.

[0012] The sand discharge gate is equipped with an upper outlet and a lower outlet. The curvature of the upper outlet and the lower outlet are different. The lower outlet is arranged horizontally to accommodate the characteristics of high sediment content water flow with large gravity and strong inertia. The upper outlet is arranged at an angle upward so that the water flow falls in a parabolic direction. The jet direction of the lower outlet is aligned with the jet core area of ​​the upper outlet so as to achieve energy dissipation through collision with the upper jet.

[0013] The water level monitoring module is used to monitor the upstream natural water level in real time. Water level in the intermediate reservoir area Downstream riverbed water level The detection data is then transmitted to the control module.

[0014] The control module is electrically connected to the bottom gate of the silt trap, the sand discharge gate, and the generator set in the inlet culvert of the generator set. It is used to adjust the opening of the bottom gate of the silt trap according to the monitoring data through an adaptive control model, maintain the water level in the intermediate reservoir area within the preset counter-flushing and energy dissipation range, ensure that the jets from the upper and lower outlets always converge precisely, and realize the linkage switching between power generation and sand discharge modes.

[0015] Furthermore, a guide sill is provided at the overflow outlet, and an inclined sand guiding surface is provided at the bottom gate, with the inclined sand guiding surface facing the sand settling troughs on both sides of the arc-shaped base.

[0016] Furthermore, the arc-shaped base adopts a variable curvature composite surface, the inclination slope of the sedimentation trough is 2% to 7%, and the surface of the arc-shaped base is provided with an anti-abrasion concrete layer.

[0017] Furthermore, the upward angle of the upper outlet is 5° to 15°, and the cross-sections of both the upper and lower outlets are flat and wide. The inner walls of the upper and lower outlets are provided with wear-resistant linings, which are made of wear-resistant steel plates or tungsten carbide weld overlays. The sand discharge gate is equipped with high-pressure water jet nozzles to assist in clearing blockages of mud and sand.

[0018] Furthermore, the jet convergence distance between the upper and lower water outlets satisfies = ,in = , = , The jet velocity at the upper outlet is [missing information]. The jet velocity at the lower outlet is [missing information]. The angle of the jet at the upper outlet. The angle of the jet at the lower outlet. This is the acceleration due to gravity.

[0019] Furthermore, a rockfall barrier is installed upstream of the silt-trapping dam. The rockfall barrier includes a dam body and a rockfall barrier grid. The dam body is set perpendicular to the water flow direction, and the angle between the dam body and the water flow direction is acute. The dam body is used to divert large-diameter rocks to the bank. The rockfall barrier grid is embedded inside the dam body, and the grid spacing of the rockfall barrier grid is 10-50cm, used to intercept large-diameter rocks with a diameter ≥10cm.

[0020] Furthermore, the adaptive control model employs PID closed-loop control and satisfies flow balance constraints, specifically:

[0021] Formula for calculating water level deviation: ,in The optimal water level for offsetting and energy dissipation is preset for the intermediate reservoir area;

[0022] Flow balance calculation formula: ,in The discharge flow from the gate of the silt trap dam, V is the total discharge flow of the main dam's sediment discharge gates, V is the effective volume of the intermediate reservoir, and t is time.

[0023] Formula for discharge flow rate from the gate of a silt-trapping dam: . Where μ is the gate flow coefficient and b is the gate width. This refers to the opening degree of the gate at the bottom of the silt trap dam;

[0024] Formula for total discharge flow rate of sand discharge gate: Where n is the number of sand-discharging gates. Here, A represents the flow coefficient of the sand discharge gate, and A is the total cross-sectional area of ​​the two outlets of a single sand discharge gate.

[0025] PID control formula for gate opening: .

[0026] Furthermore, the segmented adjustment logic of the control module is as follows: when the upstream natural water level... High time, , To maintain the maximum opening of the gates at the bottom of the silt trap dam, and to keep the water level in the intermediate reservoir area at the maximum level. ;

[0027] when At that time, PID closed-loop control is used to fine-tune the gate opening, so that... ;

[0028] according to Reduce the opening of the sand discharge gate. This represents the actual opening degree of the sand discharge gate. This represents the maximum opening of the sand discharge gate;

[0029] in, , Design-0.8, The design water level is for the upstream area.

[0030] Furthermore, the submersion depths of the upper and lower water outlets satisfy the following constraints:

[0031] , ;

[0032] in, The submersion depth at the center of the upper outlet. This refers to the submersion depth at the center of the lower outlet.

[0033] Beneficial effects:

[0034] 1. This invention utilizes an arc-shaped base with a high center and low sides at the bottom of the intermediate reservoir area. This base forms sedimentation troughs on both sides that slope towards the sand discharge gate. By leveraging gravity and the streamline characteristics of water flow, passive water-sand separation is achieved. Clean water, guided by the arc-shaped base, converges towards the center and enters the generator unit through the inlet culvert, ensuring the cleanliness of the water entering the generator. Sediment, under gravity, converges towards the sedimentation troughs on both sides. The inclined design of these troughs guides the sediment to flow naturally towards the sand discharge gate, achieving centralized discharge of sediment. This design prevents high-sand-content water from entering the generator unit at the source, effectively solving the problems of sediment erosion of turbine blades, leading to decreased unit efficiency and shortened service life in existing technologies. Furthermore, it eliminates the need for additional power to drive the water-sand separation, resulting in a simple structure, low energy consumption, significantly reducing equipment maintenance costs and downtime frequency, and improving the operational stability and continuity of the power generation system.

[0035] 2. This invention features an upper and lower outlet at the sediment discharge gate, employing a differentiated arc and arrangement angle design. The lower outlet is horizontally positioned to accommodate the high gravity and inertia of high-sediment-laden water flow, ensuring smooth sediment discharge. The upper outlet is angled upwards, causing the water flow to fall in a parabolic trajectory. The jet direction of the lower outlet is precisely aligned with the core jet area of ​​the upper outlet. Through the convergence and collision of the two water flows, momentum exchange, shear turbulence, and aeration are achieved, forcibly dissipating the kinetic energy of the water flow and achieving efficient energy dissipation. This energy dissipation method eliminates the need for complex energy dissipation structures such as stilling basins, solving the problems of large impact force, unstable energy dissipation effect, and easy erosion of the downstream riverbed caused by single outlets in existing technologies. Simultaneously, the control module maintains the water level in the intermediate reservoir within the preset counter-current energy dissipation range, ensuring that the two jets always converge precisely, avoiding the attenuation of energy dissipation effect caused by water level fluctuations. This improves the reliability of energy dissipation and protects the stability of the downstream riverbank and ecological balance. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a top view of an embodiment of the present application.

[0038] Figure 2 This is a partial cross-sectional view of the sand discharge channel according to an embodiment of this application;

[0039] Figure 3 This is a partial cross-sectional view of the generator set according to an embodiment of this application;

[0040] Figure 4 This is a partial cross-sectional view of the silt-trapping dam according to an embodiment of this application;

[0041] Figure 5 This is a partial cross-sectional view of a rock-blocking dam according to an embodiment of this application.

[0042] In the diagram: 1-Main dam body; 2-Generate intake culvert; 3-Sand discharge channel; 4-Sand discharge gate; 5-Sand barrier dam; 6-Arched base; 7-Bottom gate; 8-Upper outlet; 9-Lower outlet; 10-Guide sill; 11-Sand guide surface; 12-High-pressure water jetting nozzle; 13-Dam body; 14-Rock barrier grid. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] In the description of this application, it should be noted that the use of terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the product is in use. These terms are used solely for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the use of terms such as "first" and "second" in the description of this application is only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0047] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of this application does not imply that the component is required to be absolutely horizontal or suspended, but rather that it may be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but rather that it may be slightly tilted.

[0048] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0049] Example 1

[0050] Please refer to Figures 1-5 This embodiment provides a water conservancy and hydropower sand flushing system, including:

[0051] The main dam body 1 has a generator set water intake culvert 2 in the middle of the main dam body 1, and sand discharge channels 3 on both sides of the main dam body 1. Sand discharge gates 4 are installed on the sand discharge channels 3.

[0052] It should be noted that the main dam body 1 is used as the load-bearing and functional distribution component of the entire sand flushing system, realizing the spatial separation of power generation and sand discharge to avoid mutual interference. Specifically, the generator set water intake culvert 2 is set in the middle of the main dam body 1. Relying on the water and sand separation function of the arc-shaped base 6 in the middle reservoir area, it receives the separated clean water to provide a clean water source for the generator set and ensure the normal operation of the generator set. At the same time, the culvert is electrically connected to the control module and can be opened or closed according to the working conditions to prevent high sand content water from flowing in during sand discharge and protect the generator set from erosion by mud and sand.

[0053] Secondly, the aforementioned sand discharge channels 3 are symmetrically arranged on both sides of the main dam body 1, corresponding one-to-one with the sedimentation troughs of the arc-shaped base 6 in the intermediate reservoir area. They serve as channels for sand discharge and receive the high-sediment-laden water flow collected by the sedimentation troughs. The sand discharge gate 4 is installed on the sand discharge channel 3 and is controlled by the control module. By adjusting the gate opening, the sand discharge flow rate is controlled. In conjunction with the water level adjustment in the intermediate reservoir area, the sand discharge efficiency and energy dissipation effect are coordinated. At the same time, it is closed during power generation to prevent the loss of clean water from the sand discharge channel 3 and ensure sufficient water source for power generation.

[0054] A sediment trap 5 is located upstream of the main dam 1, forming an intermediate reservoir between the main dam 1 and the sediment trap 5. An arc-shaped base 6 is provided at the bottom of the intermediate reservoir. The arc-shaped base 6 has a curved surface structure that is high in the middle and low on both sides. Sedimentation troughs are formed on both sides of the arc-shaped base 6. The bottom of the sedimentation troughs is inclined towards the discharge gate. The position of the sedimentation troughs corresponds one-to-one with the position of the discharge gate. An adjustable bottom gate 7 is provided on the sediment trap 5. An overflow outlet is provided at the top of the sediment trap 5.

[0055] It should be noted that the aforementioned silt-trapping dam 5 is located upstream of the main dam body 1 and is used for pre-emptive silt trapping and water flow regulation, providing stable conditions for water-sediment separation and energy dissipation in the intermediate reservoir area. Specifically, the main body of the aforementioned silt-trapping dam 5 is used to intercept some of the sediment in the upstream water, reducing the total amount of sediment entering the intermediate reservoir area and alleviating the siltation pressure in the intermediate reservoir area. At the same time, the silt-trapping dam 5 and the main dam body 1 form an intermediate reservoir area, providing necessary space for water flow buffering, water-sediment separation, and jet counter-current energy dissipation, and preventing the upstream water flow from directly impacting the main dam body 1 and the silt discharge gate 4. The aforementioned adjustable bottom gate 7 is a regulating component for the water level and flow rate in the intermediate reservoir area. The opening is dynamically adjusted by the control module based on water level monitoring data. By adjusting the gate height, the flow velocity and flow rate of the water entering the intermediate reservoir area are controlled, thereby maintaining the water level in the intermediate reservoir area within the preset counter-current energy dissipation range and ensuring the precise convergence of the jets from the double-layer outlet. At the same time, during the sand discharge operation, the gate is fully opened, allowing the sediment accumulated in the sand-blocking dam 5 to quickly flow into the intermediate reservoir area, improving the sand discharge efficiency.

[0056] The aforementioned top overflow outlet is adapted to the water flow guidance requirements of power generation operation. When the bottom gate 7 of the silt trap 5 is closed, the upstream water cannot enter the intermediate reservoir from the bottom. At this time, the water flows smoothly through the overflow outlet to the intermediate reservoir, avoiding the impact of the upstream water level on the silt trap 5, while ensuring that the water flows smoothly into the intermediate reservoir, and ensuring the stable water and sand separation effect of the arc-shaped base 6.

[0057] The aforementioned intermediate reservoir serves as a buffer for water flow and a carrier for water-sediment separation. It receives water from the overflow of the silt barrier 5 or the discharge from the bottom gate 7, providing sufficient time for sediment to settle and for clear water to converge. At the same time, the water level changes in the intermediate reservoir directly affect the jet effect of the double-layer outlet. Therefore, its water level needs to be regulated by the bottom gate 7 of the silt barrier 5 to maintain it within the preset range, ensuring a stable energy dissipation effect.

[0058] Furthermore, the aforementioned arc-shaped base 6 utilizes the gravity and streamline characteristics of water flow to achieve passive water-sand separation without the need for additional power. After the water flows into the intermediate reservoir area, it exhibits a flow state of converging in the middle and splitting on both sides under the guidance of the curved surface of the arc-shaped base 6. The clear water has low density and low inertia, and converges towards the center along the high convex area of ​​the arc-shaped base 6, eventually entering the generator unit's inlet culvert 2. The sediment has high density and high inertia, and under the action of gravity and water flow turbulence, it settles towards the low concave areas on both sides of the arc-shaped base 6, forming sedimentation troughs.

[0059] The aforementioned sedimentation trough receives the sediment separated from the arc-shaped base 6. The bottom of the sedimentation trough is inclined towards the sand discharge gate 4, allowing the deposited sediment to slide naturally towards the sand discharge gate 4, achieving concentrated sediment accumulation and preventing sediment from accumulating evenly at the bottom of the intermediate reservoir area. At the same time, the sedimentation trough and the sand discharge gate 4 correspond one-to-one, ensuring that the collected sediment can accurately enter the sand discharge channel 3, improving sand discharge efficiency and reducing the probability of blockage in the sand discharge channel.

[0060] The sand discharge gate is equipped with an upper outlet 8 and a lower outlet 9. The curvature of the upper outlet 8 and the lower outlet 9 are different. The lower outlet 9 is arranged horizontally to adapt to the characteristics of high sediment content water flow with large gravity and strong inertia. The upper outlet 8 is arranged inclined upwards so that the water flow falls in a parabolic direction. The jet direction of the lower outlet 9 is aligned with the jet core area of ​​the upper outlet 8 to achieve energy dissipation through collision with the upper jet.

[0061] In this embodiment, the lower outlet 9 is adapted to the physical characteristics of high sediment-laden water flow. High sediment-laden water flow has high gravity and strong inertia. Horizontal arrangement can ensure that the water flow is ejected in a straight line, avoiding sediment deposition at the outlet due to changes in the water flow direction, and ensuring smooth discharge of sediment. At the same time, the kinetic energy of the horizontal jet is concentrated, which can accurately target the jet core area of ​​the upper outlet 8, providing a basis for the convergence and collision of the two water flows.

[0062] The aforementioned upper outlet 8 is designed to make the water flow fall in a parabolic trajectory after it is ejected. The upward tilt angle is used to increase the projection height and distance of the water flow, so that the upper water flow and the lower horizontal jet can accurately converge in the downstream airspace. At the same time, the design of different curvatures can further optimize the convergence angle of the two water flows, ensuring that the core areas of the jets completely overlap and maximizing the energy dissipation effect.

[0063] When the lower horizontal jet and the upper parabolic jet meet, the two water flows collide violently, shear, and break up with air. The upward kinetic energy of the upper water flow is offset by the horizontal kinetic energy of the lower water flow, and the momentum of the water flows is exchanged. The concentrated kinetic energy of the water flow is converted into turbulent energy, which is then dissipated through water flow eddies, friction, and other forms. Ultimately, the kinetic energy of the water flow is greatly reduced, which reduces the impact of the sediment discharge flow on the downstream riverbed and avoids riverbed erosion and bank instability.

[0064] The water level monitoring module is used to monitor the upstream natural water level in real time. Water level in the intermediate reservoir area Downstream riverbed water level The detection data is then transmitted to the control module.

[0065] It should be noted that the water level monitoring module mentioned above is the foundation for realizing adaptive control. It is used to collect three types of key water level data in real time during the system operation, providing accurate basis for the adjustment commands of the control module.

[0066] Specifically, upstream natural water level It is used to monitor the changes in the water level of upstream water in real time, capture the high, medium and low fluctuations of the upstream water level, and provide a reference for the control module to adjust the opening of the bottom gate of the silt trap dam.

[0067] The water level of the aforementioned intermediate reservoir area Real-time monitoring of the actual water level in the intermediate reservoir area and its comparison with the preset counter-offset energy dissipation water level. Compare and calculate the water level deviation. This deviation is a parameter used by the control module to adjust the opening of the gate at the bottom of the silt trap dam, ensuring that the water level in the intermediate reservoir area is maintained within the preset range.

[0068] Downstream riverbed water level Real-time monitoring of downstream riverbed water level changes helps determine the discharge status of sediment discharge water, preventing excessively high downstream water levels from causing sediment discharge water to backflow, affecting sediment discharge efficiency and energy dissipation effect. It also provides a reference for the control module to fine-tune the opening of the sediment discharge gate 4.

[0069] The control module is electrically connected to the bottom gate 7 of the silt trap 5, the sand discharge gate, and the generator set in the generator set inlet culvert 2. It is used to adjust the opening of the bottom gate 7 of the silt trap 5 according to the monitoring data through an adaptive control model, maintain the water level in the intermediate reservoir area within the preset counter-current energy dissipation range, ensure that the jets of the upper outlet 8 and the lower outlet 9 always converge precisely, and realize the linkage switching between power generation and sand discharge modes.

[0070] Based on a PID closed-loop control algorithm and combined with the principle of flow balance, the goal is to maintain the water level in the intermediate reservoir within a preset offsetting and energy dissipation range, by controlling the water level deviation. The opening of the bottom gate of the silt trap is dynamically adjusted to form a closed-loop control of monitoring, comparison, adjustment and feedback, so as to ensure the stability of the water level in the intermediate reservoir area and thus ensure the precise convergence of the jets from the two outlets.

[0071] The gate opening adjustment is achieved by the control module calculating the optimal gate opening based on water level monitoring data and the formula of the adaptive control model, and then driving the bottom gate of the silt trap to complete the adjustment.

[0072] For example: At that time, increase the gate opening to increase the water flow into the intermediate reservoir and raise the water level; when At the same time, reduce the gate opening, decrease the water flow, and lower the water level; simultaneously, consider the upstream water level. The fluctuations are addressed using segmented adjustment logic to ensure precise and rapid adjustment.

[0073] During the switching of operating conditions, the control module controls the bottom gate 7 of the sand-removing dam 5, the sand-discharging gate 4, and the generator set to achieve seamless switching between power generation and sand discharge conditions.

[0074] During power generation, the control module issues a command to close the bottom gate 7 and the sand discharge gate 4 of the sand-blocking dam 5. The upstream water flows into the intermediate reservoir area through the overflow port at the top of the sand-blocking dam 5. After water and sand are separated by the arc-shaped base 6, the clean water enters the water intake culvert 2 of the generator set and drives the generator set to generate electricity.

[0075] During the sand discharge operation, the control module issues a command to shut down the generator set and open the bottom gate 7 and the sand discharge gate 4 of the sand-blocking dam 5. The sediment in the sand-blocking dam 5 enters the intermediate reservoir area together with the water flow. After being collected in the sedimentation tank, it is discharged through the double-layer outlet. At the same time, the control module adjusts the opening of the bottom gate 7 of the sand-blocking dam 5 to maintain the water level in the intermediate reservoir area and ensure the stability of the flushing and energy dissipation effect.

[0076] The control module automatically switches operating conditions based on siltation and power generation needs. During the switching process, the switching sequence of each component is strictly controlled to prevent silt from entering the generator set, ensuring safe and convenient switching.

[0077] Further, please refer to Figures 1-5 The overflow outlet is provided with a guide sill 10, and the bottom gate 7 is provided with an inclined sand guide surface 11, which faces the sand settling troughs on both sides of the arc-shaped base 6.

[0078] In this embodiment, the aforementioned guide sill 10 is installed at the top overflow outlet of the silt trap 5 to guide the overflow water flow during power generation into the intermediate reservoir smoothly and orderly, preventing turbulent water flow from affecting the water-sand separation effect of the arc-shaped base 6, and protecting the structural safety of the silt trap 5 and the intermediate reservoir. During power generation, the bottom gate 7 of the silt trap 5 is closed, and the upstream water needs to overflow into the intermediate reservoir through the top overflow outlet. Since the water flow velocity at the overflow outlet is relatively fast, and the water flow is prone to lateral diffusion and severe turbulence, the guide sill 10, through its own blocking and guiding effect, gathers the dispersed overflow water flow and guides it to the preset flow direction.

[0079] In this embodiment, the inclined sand guiding surface 11 is set at the bottom gate 7 of the sand-blocking dam 5 and faces the sedimentation troughs on both sides of the arc-shaped base 6. It uses gravity to guide the high-sediment-content water flow and the silt accumulated in the sand-blocking dam 5 under the sand discharge condition, and accurately and quickly flow into the sedimentation trough of the intermediate reservoir area, thereby improving the sand discharge efficiency and avoiding the accumulation and blockage of silt at the bottom gate 7.

[0080] Further, please refer to Figure 1 The arc-shaped base 6 adopts a variable curvature composite surface, the inclination slope of the sedimentation trough is 2% to 7%, and the surface of the arc-shaped base 6 is provided with an anti-abrasion concrete layer.

[0081] In this embodiment, the aforementioned variable curvature composite surface is designed with different curvatures in different areas of the arc-shaped base 6 according to the water flow direction and velocity distribution in the intermediate reservoir area. The central high-convex area adopts a larger curvature, while the two sides transitioning to the sedimentation trough adopt a smaller curvature. When the water flows from the dam 5 into the intermediate reservoir area, the surface with a larger curvature in the center can quickly guide the clean water to converge in the center, providing a stable clean water source for the generator unit's intake culvert 2; the surfaces with smaller curvatures on both sides gently guide the sand-laden water to flow into the sedimentation trough in the low-lying areas on both sides, avoiding excessive water flow turbulence that could cause sediment to be resuspended, and ensuring stable water-sand separation.

[0082] The variable curvature design can effectively slow down the flow velocity of water on the surface of the arc-shaped base 6, especially in the inlet area of ​​the sedimentation tank. By adjusting the curvature, the intensity of water flow turbulence is reduced, providing sufficient time for sediment to settle. This allows the sediment in the water flow to settle smoothly into the sedimentation tank under the action of gravity, preventing sediment from entering the generator set's inlet culvert 2 with the clean water, thus protecting the generator set from the source.

[0083] Specifically, the slope of the sedimentation trough is set at 2% to 7%. This slope range has been optimized through engineering. It can provide sufficient power for the flow of sediment by utilizing the component of gravity, so that the sediment deposited at the bottom of the sedimentation trough can slide smoothly towards the discharge gate under the action of its own gravity and the thrust of the water flow. It can also avoid the situation where the slope is too large, resulting in excessive water flow velocity and excessive scouring of sediment, or the slope is too small, resulting in sediment retention and accumulation.

[0084] Further, please refer to Figures 1-3 The upward angle of the upper outlet 8 is 5° to 15°. The cross-sections of the upper outlet 8 and the lower outlet 9 are both flat and wide. The inner walls of the upper outlet 8 and the lower outlet 9 are provided with wear-resistant linings, which are made of wear-resistant steel plates or tungsten carbide weld overlays. A high-pressure water jet nozzle 12 is provided at the entrance of the sand discharge gate to assist in clearing blocked mud and sand.

[0085] In this embodiment, an upward angle of 5° to 15° is adopted through engineering optimization. This ensures that the upper water flow forms a stable parabolic trajectory after being ejected, while also controlling the projection distance and height of the jet. This ensures that the core area of ​​the upper jet can accurately intersect with the lower horizontal jet. If the angle is too small, the trajectory of the upper jet will be too flat, and it will not be able to form an effective collision with the lower jet. If the angle is too large, the upper jet will be projected too high and too far, causing the jet to deviate and the energy dissipation effect to decrease.

[0086] Using a flat and wide cross-section allows the water flow to form a flat jet after it is ejected, increasing the lateral coverage of the jet and maximizing the intersection area between the upper and lower flat and wide jets. This improves the uniformity and effectiveness of counter-current energy dissipation and avoids the problems of concentrated intersection points and uneven energy dissipation caused by single circular cross-section jets.

[0087] Wear-resistant steel plates or tungsten carbide weld overlays are used in the wear-resistant lining of the outlet to improve the outlet's resistance to abrasion, extend its service life, and ensure long-term stability of the jet pattern and sand removal function.

[0088] Furthermore, the jet convergence distance between the upper outlet 8 and the lower outlet 9 satisfies = ,in = , = , The jet velocity at the upper outlet is [missing information]. The jet velocity at the lower outlet is [missing information]. The angle of the jet at the upper outlet. The angle of the jet at the lower outlet. This is the acceleration due to gravity.

[0089] It should be noted that the above The confluence distance of the upper water outlet 8 jets is the horizontal distance from which the upper water flow moves along the designed trajectory to the point of confluence with the lower jet after it is ejected from the outlet. This refers to the confluence distance of the jets from the lower outlet 9, that is, the horizontal distance the lower horizontal jet travels from the outlet to the confluence point. Requirements: This ensures that the two jets meet precisely at the same horizontal position, forming an effective collision, and avoids jet deviation that would lead to a decrease in energy dissipation effect.

[0090] Furthermore, a rockfall barrier is provided upstream of the silt barrier 5. The rockfall barrier includes a dam body 13 and a rockfall barrier grid 14. The dam body 13 is set perpendicular to the water flow direction, and the angle between the dam body 13 and the water flow direction is acute. The dam body 13 is used to divert large-diameter rocks to the bank. The rockfall barrier grid 14 is embedded inside the dam body 13. The grid spacing of the rockfall barrier grid 14 is 10-50cm, and it is used to intercept large-diameter rocks with a diameter ≥10cm.

[0091] In this embodiment, the dam body 13 is arranged perpendicular to the water flow direction, which can maximize the interception of large-diameter stones in the water flow, prevent the stones from moving downstream with the water flow, and prevent them from entering the area of ​​the silt barrier 5. At the same time, the dam body 13 can slow down the flow rate of the upstream water, providing a stable water flow environment for the subsequent precise interception of the rock barrier 14, and preventing stones from passing through the grating due to excessive water flow speed.

[0092] Furthermore, the dam body 13 forms an acute angle with the direction of water flow. When the water flow carries large-diameter stones and impacts the dam body 13, the water flow and stones will be subjected to the lateral thrust of the dam body 13. Under the combined action of this thrust and the inertia of the water flow, the stones will slide towards the bank along the acute angle tilt direction of the dam body 13, thereby achieving the directional diversion of large-diameter stones, preventing stones from accumulating in front of the dam body 13, and ensuring that the interception channel of the rock-blocking dam is unobstructed.

[0093] In this embodiment, the aforementioned rock-blocking grid 14 is embedded inside the dam body 13, with a grid spacing of 10-50cm. The core working principle is to precisely intercept large-diameter stones with a diameter ≥10cm in the water flow through physical interception, while allowing clear water and fine silt to pass through, thus achieving the goal of blocking rocks without blocking water and blocking large stones without blocking small ones.

[0094] Furthermore, the adaptive control model employs PID closed-loop control and satisfies flow balance constraints, specifically:

[0095] Formula for calculating water level deviation: ,in The optimal water level for offsetting and energy dissipation is preset for the intermediate reservoir area;

[0096] Flow balance calculation formula: ,in The discharge flow from the gate of the silt trap dam, V is the total discharge flow of the main dam's sediment discharge gates, V is the effective volume of the intermediate reservoir, and t is time.

[0097] Formula for discharge flow rate from the gate of a silt-trapping dam: . Where μ is the gate flow coefficient and b is the gate width. This refers to the opening degree of the gate at the bottom of the silt trap dam;

[0098] Formula for total discharge flow rate of sand discharge gate: Where n is the number of sand-discharging gates. Here, A represents the flow coefficient of the sand discharge gate, and A is the total cross-sectional area of ​​the two outlets of a single sand discharge gate.

[0099] PID control formula for gate opening: .

[0100] The PID control parameters are set as follows: =1.0, =0.1, =0.2, The initial opening of the gate; the gate flow coefficient. =0.75, flow coefficient of the sand discharge gate =0.8; upstream design water level =100m, then =100.8m, =99.2m, the intermediate reservoir area is preset with the optimal water level for counter-current energy dissipation. =98m; the submersion depth of the upper and lower outlets meets the following requirements: , .

[0101] Furthermore, the segmented adjustment logic of the control module is as follows: when the upstream natural water level... High time, , To maintain the maximum opening of the gates at the bottom of the silt trap dam, and to keep the water level in the intermediate reservoir area at the maximum level. ;

[0102] when At that time, PID closed-loop control is used to fine-tune the gate opening, so that... ;

[0103] according to Reduce the opening of the sand discharge gate. This represents the actual opening degree of the sand discharge gate. This represents the maximum opening of the sand discharge gate;

[0104] in, , Design-0.8, The design water level is for the upstream area.

[0105] in, , Design-0.8, The design water level is for the upstream area.

[0106] , ;

[0107] in, The submersion depth at the center of the upper outlet. This refers to the submersion depth at the center of the lower outlet.

[0108] For example:

[0109] The water level monitoring module collects three types of water level data in real time, and the control module calculates the water level deviation. The opening of the bottom gate of the silt trap dam is adjusted by combining the flow balance formula, PID control formula, and segmented regulation logic: when hour, =0.6 ,maintain When 99.2m At that time, PID closed-loop control is used to fine-tune the gate opening, so that... ;when hour, ,like Then according to Reduce the opening of the sand discharge gate to ensure that the jets always converge precisely and the energy dissipation effect is stable.

[0110] Example 2

[0111] Based on the aforementioned water conservancy and hydropower sand flushing system, this embodiment provides a control method for the water conservancy and hydropower sand flushing system, the steps of which are as follows:

[0112] S101: The water flow first passes through the rock-blocking dam, where the rock-blocking grid 14 intercepts the large-diameter stones. The intercepted stones are discharged to the waste rock area on the bank through the waste rock channel. The pre-treated water flows to the sand-blocking dam 5, and the bottom gate 7 of the sand-blocking dam 5 is closed. The water overflows from the top overflow outlet of the sand-blocking dam 5 to the arc-shaped base 6. Under the action of the arc-shaped base 6 and the guide protrusion, the clear water converges to the middle and enters the generator unit through the generator unit inlet culvert 2. The sediment is deposited on both sides of the sedimentation tank under the action of gravity and water flow turbulence. The sand-blocking sill and the static sedimentation zone further intercept fine sand and reduce the sediment content of the inlet water.

[0113] S102: Close the generator set inlet culvert 2, open the bottom gate 7 of the silt trap 5 and the sand discharge gates on both sides of the main dam body 1. The sediment in the silt trap 5 flows into the sedimentation troughs on both sides of the arc-shaped base 6 through the inclined sand guiding surface 11, and is then discharged through the upper and lower outlets of the sand discharge gate 4. The lower layer of horizontal jet and the upper layer of obliquely upward parabolic jet collide to achieve energy dissipation. During the sand discharge process, the rock trap dam continuously intercepts large-diameter stones from upstream to prevent them from entering the area between the silt trap dam 5 and the main dam body 1.

[0114] S103: Water level monitoring module collects upstream natural water level data in real time. Water level in the intermediate reservoir area and downstream riverbed water level The control module adjusts according to the water level deviation. By combining the flow balance formula, PID control formula and segmented adjustment logic of the adaptive control model, the opening of the bottom gate 7 of the silt trap 5 is adjusted to maintain the water level in the intermediate reservoir area within the preset counter-current energy dissipation range, ensuring that the jets from the upper and lower outlets always converge precisely and guaranteeing a stable energy dissipation effect.

[0115] S104: Based on the siltation situation and power generation needs, repeat steps S1-S3 to achieve seamless switching between power generation and silt discharge conditions. During the switching process, avoid high-silt-content water flow from entering the generator unit. Regularly open the silt discharge gate of the silt discharge channel to discharge large-diameter stones intercepted by the rock barrier dam and prevent the rock barrier grid 14 from becoming blocked.

[0116] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A water conservancy and hydropower sand washing system, characterized in that, include: The main dam body (1) has a generator set water intake culvert (2) in the middle of the main dam body (1), and sand discharge channels (3) on both sides of the main dam body (1). Sand discharge gates (4) are installed on the sand discharge channels (3). A sediment trap (5) is set upstream of the main dam body (1). An intermediate reservoir area is formed between the main dam body (1) and the sediment trap (5). An arc-shaped base (6) is set at the bottom of the intermediate reservoir area. The arc-shaped base (6) has a curved surface structure that is high in the middle and low on both sides. Sedimentation troughs are formed on both sides of the arc-shaped base (6). The bottom of the sedimentation troughs is inclined towards the direction of the sand discharge gate. The position of the sedimentation troughs corresponds one-to-one with the position of the sand discharge gate. An adjustable bottom gate (7) is set on the sediment trap (5). An overflow outlet is set on the top of the sediment trap (5). The sand discharge gate is equipped with an upper outlet (8) and a lower outlet (9). The curvature of the upper outlet (8) and the curvature of the lower outlet (9) are different. The lower outlet (9) is arranged horizontally to adapt to the characteristics of high sediment content water flow with large gravity and strong inertia. The upper outlet (8) is arranged inclined upward so that the water flow falls in a parabolic direction. The jet direction of the lower outlet (9) is aligned with the jet core area of ​​the upper outlet (8) to achieve energy dissipation by colliding with the upper jet. a water level monitoring module for monitoring the upstream natural water level in real time , the intermediate reservoir area water level , the downstream riverbed water level and transmitting the detection data to the control module; The control module is electrically connected to the bottom gate (7) of the silt trap (5), the sand discharge gate, and the generator set in the generator set inlet culvert (2). It is used to adjust the opening of the bottom gate (7) of the silt trap (5) according to the monitoring data through the adaptive control model, maintain the water level in the intermediate reservoir area within the preset counter-current energy dissipation range, ensure that the jets of the upper outlet (8) and the lower outlet (9) always converge precisely, and realize the linkage switching of power generation and sand discharge operation.

2. The hydraulic sand flushing system according to claim 1, characterized in that, The overflow outlet is provided with a guide sill (10), and the bottom gate (7) is provided with an inclined sand guide surface (11), which faces the sand settling troughs on both sides of the arc-shaped base (6).

3. The hydraulic sand flushing system according to claim 1, wherein, The arc-shaped base (6) adopts a variable curvature composite surface, the slope of the sedimentation trough is 2% to 7%, and the surface of the arc-shaped base (6) is provided with an anti-abrasion concrete layer.

4. The hydraulic sand flushing system of claim 1, wherein, The upward angle of the upper outlet (8) is 5° to 15°. The cross-sections of the upper outlet (8) and the lower outlet (9) are both flat and wide. The inner walls of the upper outlet (8) and the lower outlet (9) are provided with wear-resistant linings. The wear-resistant linings are made of wear-resistant steel plates or tungsten carbide weld overlays. A high-pressure water jet nozzle (12) is provided at the entrance of the sand discharge gate to assist in clearing the blocked mud and sand.

5. A water conservancy and hydropower sand flushing system according to claim 1, characterized in that, The jet intersection distance of the upper water outlet (8) and the lower water outlet (9) satisfies = , = , = , is the jet flow velocity of the upper water outlet, is the jet flow velocity of the lower water outlet, is the jet angle of the upper water outlet, is the jet angle of the lower water outlet, is the acceleration of gravity.

6. The hydraulic sand flushing system of claim 1, wherein, An upstream rock-blocking dam is provided for the silt-blocking dam (5). The rock-blocking dam includes a dam body (13) and a rock-blocking grid (14). The dam body (13) is set perpendicular to the direction of water flow, and the angle between the dam body (13) and the direction of water flow is acute. The dam body (13) is used to guide large-diameter stones to the bank. The rock-blocking grid (14) is embedded inside the dam body (13). The grid spacing of the rock-blocking grid (14) is 10-50cm, and it is used to intercept large-diameter stones with a diameter ≥10cm.

7. The hydraulic sand flushing system of claim 5, wherein, The adaptive control model employs PID closed-loop control and satisfies flow balance constraints, specifically: Formula for calculating water level deviation: ,in The optimal water level for offsetting and energy dissipation is preset for the intermediate reservoir area; Flow balance calculation formula: ,in The discharge flow from the gate of the silt trap dam, V is the total discharge flow of the main dam's sediment discharge gates, V is the effective volume of the intermediate reservoir, and t is time. Formula for discharge flow rate from the gate of a silt-trapping dam: . Where μ is the gate flow coefficient and b is the gate width. This refers to the opening degree of the gate at the bottom of the silt trap dam; Formula for total discharge flow rate of sand discharge gate: Where n is the number of sand-discharging gates. Here, A represents the flow coefficient of the sand discharge gate, and A is the total cross-sectional area of ​​the two outlets of a single sand discharge gate. PID control formula for gate opening: ,in This is the proportionality coefficient. Integral coefficient, The differential coefficients are... This represents the initial opening of the gate.

8. A water conservancy and hydropower sand flushing system according to claim 1, characterized in that, The segmented adjustment logic of the control module is as follows: When the upstream natural water level High time, , To maintain the maximum opening of the gates at the bottom of the silt trap dam, and to keep the water level in the intermediate reservoir area at the maximum level. ; when At that time, PID closed-loop control is used to fine-tune the gate opening, so that... ; according to Reduce the opening of the sand discharge gate. This represents the actual opening degree of the sand discharge gate. This represents the maximum opening of the sand discharge gate; in, , Design-0.8, The design water level is for the upstream area.

9. A water conservancy and hydropower sand flushing system according to claim 1, characterized in that, The submergence depths of the upper outlet (8) and the lower outlet (9) satisfy the following constraints: , ; in, The submersion depth at the center of the upper outlet (8) The submersion depth of the center of the lower outlet (9).

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