Novel stilling basin emptying and desilting system

Abstract

The invention belongs to the technical field of flood discharge and energy dissipation in water conservancy and hydropower engineering, and particularly relates to a novel stilling pool emptying and desilting system. The first groove and the second groove are formed in the bottom plate of the stilling basin and the upstream face of the tail sill in the novel stilling basin emptying and desilting system respectively, the first groove and the second groove are connected to form the reverse arc curved surface, when water flow carrying silt enters the reverse arc curved surface at a certain speed, the water flow can form spiral flow in the reverse arc curved surface, and therefore the silt can be discharged out of the bottom of the stilling basin. When the stilling pool is used, one part of water flow traces towards the upstream and is discharged out of the reverse arc curved surface, the other part of water flow still carries silt to enter the reverse arc curved surface, then moves towards the two ends of the tail sill and flows into the downstream, in the whole process, the silt on the bottom plate of the stilling pool is discharged, abrasion of the silt to the stilling pool is effectively reduced, and therefore the service life of the stilling pool is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of flood discharge and energy dissipation in water conservancy and hydropower engineering, and in particular relates to a novel stilling pool emptying and sand removal system. Background Art

[0002] In many low-head small and medium-sized water conservancy projects in my country, bottom flow energy dissipation is the main energy dissipation method. Bottom flow energy dissipation has the characteristics of strong adaptability, especially in low head conditions. The higher the head, the greater the energy dissipation rate. At the same time, the advantages of connection with tailwater, small turbulence fluctuation, and uniform flow velocity distribution are more obvious.

[0003] The essence of bottom flow energy dissipation is to use energy dissipation pools or energy dissipation sills to force the water flow to form a hydraulic jump at a specific location, thereby achieving the purpose of utilizing hydraulic jump to dissipate energy.

[0004] In order to improve the tailwater raising effect, stilling pools usually use higher tailwater sills. However, sediment, especially bedload sediment, often accumulates in stilling pools. When flood discharge is carried out, the water flow carries large particles of sediment into the stilling pool. Some of the sediment may be deposited in the stilling pool and cannot be discharged naturally, which will affect the performance of the stilling pool and increase the risk of abrasion damage. At the same time, sediment is deposited at the bottom of the stilling pool. If it cannot be discharged in time, it will affect the service life of the stilling pool. Summary of the invention

[0005] The purpose of the present invention is to provide a novel stilling pool emptying and sand removal system to solve the technical problem in the prior art that the stilling pool cannot be naturally discharged due to sediment deposition, thereby affecting the performance and service life of the stilling pool.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A novel stilling pool emptying and sand removal system comprises a stilling pool bottom plate and a tail sill, wherein the tail sill is arranged at the end of the stilling pool bottom plate, and a first groove concave downward is arranged on the stilling pool bottom plate, wherein the length direction of the first groove is parallel to the length direction of the tail sill;

[0008] The water-facing surface of the tail sill is provided with a second groove recessed toward the head end away from the bottom plate of the energy dissipation pool, the length direction of the second groove is parallel to the length direction of the tail sill, and the lower side of the second groove is connected with the side of the head end of the first groove away from the bottom plate of the energy dissipation pool to form an anti-arc curved surface;

[0009] When the water carrying sediment flows from upstream to the anti-arc surface, the water will form a spiral flow in the anti-arc surface. Part of the water will flow upstream and discharge out of the anti-arc surface, and the other part of the water will carry sediment and move toward the two ends of the tail bank in the anti-arc surface and flow into the downstream.

[0010] In order to better realize the present invention, further optimization is made in the above structure, the cross-sectional shape of the first groove is 1 / 2 arc, the cross-sectional shape of the second groove is 1 / 4 arc, the radius of the first groove is equal to the radius of the second groove, and the center of the first groove coincides with the center of the second groove.

[0011] In order to better implement the present invention, further optimization is made in the above structure, and a sand-trapping net ridge is arranged at the opening of the anti-arc curved surface, and the two sides of the sand-trapping net ridge are respectively connected to the two sides of the anti-arc curved surface.

[0012] In order to better implement the present invention, further optimization is made in the above structure, and steel ribs are arranged on the ridges of the sand-trapping net.

[0013] In order to better implement the present invention, further optimization is made in the above structure, the cross-sectional shape of the sand-trapping net ridge is a 1 / 4 arc, and the radius of the sand-trapping net ridge is equal to the radius of the first groove.

[0014] In order to better implement the present invention, further optimization is made in the above structure, and the radius of the first groove is greater than three times the median particle size of the sediment carried in the water flow.

[0015] In order to better implement the present invention, further optimization is made in the above structure, the height of the tail sill is greater than 8m, and the height of the upper side of the second groove is not less than half of the height of the tail sill.

[0016] In order to better implement the present invention, further optimization is made in the above structure, the height of the tail sill is less than 8m, and the height of the upper side of the second groove is not less than 2m.

[0017] In order to better realize the present invention, further optimization is made in the above structure. Sand removal vortex tubes are provided at both ends of the tail sill. The water inlet end of the sand removal vortex tube is connected to the two ends of the reverse arc surface, and the water outlet end of the sand removal vortex tube extends to the downstream.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The first groove and the second groove are respectively arranged on the water-facing surface of the bottom plate of the energy stilling pool and the tail sill in the novel energy stilling pool emptying and sand discharge system provided by the present invention. The first groove and the second groove are connected to form an anti-arc curved surface. When the water flow carrying sediment enters the anti-arc curved surface at a certain speed, the water flow will form a spiral flow in the anti-arc curved surface. Part of the water flow will flow upstream and discharge out of the anti-arc curved surface, and the other part of the water flow still carries the sediment and moves toward the two ends of the tail sill after entering the anti-arc curved surface and flows into the downstream. During the whole process, the sediment on the bottom plate of the energy stilling pool is discharged, the erosion of the sediment on the energy stilling pool is effectively reduced, and the service life of the energy stilling pool is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a structural diagram of a traditional tail sill stilling pool;

[0022] Figure 2 A schematic diagram of the structure of a novel stilling pool emptying and sand removal system provided by the present invention;

[0023] Figure 3 A top view of a novel stilling pool emptying and sand removal system provided by the present invention;

[0024] Figure 4 A schematic diagram of the sand discharge process of a novel stilling pool emptying and sand discharge system provided by the present invention;

[0025] Figure 5 A schematic diagram of various parameters of a novel stilling pool emptying and sand removal system provided by the present invention.

[0026] In the figure:

[0027] 1-tail sill, 2-energy dissipation pool bottom plate, 3-reverse arc surface, 4-guide wall, 5-sand discharge vortex tube, 6-sand retaining net ridge, 7-tank protection. DETAILED DESCRIPTION

[0028] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that, unless otherwise specified, the meaning of "plurality" is two or more; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In an embodiment of the present invention, Figures 1 to 5 As shown, the novel stilling pool emptying and sand removal system comprises a stilling pool bottom plate 2 and a tail sill 1, wherein the tail sill 1 is arranged at the end of the stilling pool bottom plate 2, a guard 7 is arranged on the side of the tail sill 1 away from the stilling pool, guide walls 4 are arranged on both sides of the stilling pool, and a first groove concave downward is arranged on the stilling pool bottom plate 2, and the length direction of the first groove is parallel to the length direction of the tail sill 1;

[0032] The water-facing surface of the tail sill 1 is provided with a second groove recessed toward the head end away from the stilling pool bottom plate 2, the length direction of the second groove is parallel to the length direction of the tail sill 1, and the lower side of the second groove is connected with the side of the first groove away from the head end of the stilling pool bottom plate 2 to form an anti-arc curved surface 3;

[0033] When the water carrying sediment enters the anti-arc surface 3 at a certain speed, the water will form a spiral flow in the anti-arc surface 3, and part of the water will flow upstream and discharge from the anti-arc surface 3, see Figure 5 , the other part of the water flow still carries the sediment and moves to the two ends of the tail bank 1 after entering the anti-arc surface 3, and flows into the downstream, see Figure 4 During the whole process, the sediment on the bottom plate 2 of the energy dissipation pool is discharged, which effectively reduces the abrasion of the sediment on the energy dissipation pool, thereby increasing the service life of the energy dissipation pool.

[0034] In some embodiments, both ends of the tail sill 1 are provided with a sand removal vortex tube 5. Figure 3 and Figure 4 The water inlet end of the sand discharge vortex tube 5 is connected to the two ends of the reverse arc surface 3, and the water outlet end of the sand discharge vortex tube 5 extends to the downstream, making it more convenient to discharge the sediment entering the reverse arc surface 3.

[0035] It is worth noting that the above-mentioned anti-arc surface 3 is a 3 / 4 arc, and the selection of the radius of the anti-arc surface 3 depends on the size of the sediment particle size and the height of the tail sill 1 itself: on the one hand, the radius of the anti-arc surface 3 should be greater than three times the median particle size of the sediment carried in the water flow to ensure that most of the sediment can be discharged in time;

[0036] On the other hand, the upper end of the reverse curved surface 3 (above the second groove) is a vertical section. A certain vertical section should be left above the reverse curved surface 3. The length of the vertical section is h, so that the weight of the tail sill 1 itself will not be reduced too much, ensuring that there will be no safety accidents such as the tail sill 1 turning over due to excessive water flow. The height of the tail sill 1 is specifically divided into the following two situations:

[0037] In the tail sill 1 with a height exceeding 8m, the height of the vertical section (the height at which the upper side of the second groove is located) is not less than half of the height Δ of the tail sill 1, that is,

[0038] h≧1 / 2Δm;

[0039] In the tail sill 1 with a height of less than 8m, the height of the vertical section should not be less than 2m, that is

[0040] h≧2m.

[0041] At the same time, considering economic factors, the radius of the reverse arc surface 3 should be as small as possible.

[0042] For example, if the median particle size of sediment in a river is 30cm and the height of the tail bank 1 is 5m, considering sediment discharge, safety factors and economic factors, the radius of the anti-arc surface 3 should range from 0.9m to 3m. Taking economic factors into consideration, the radius of the anti-arc surface 3 should be set to 0.9m.

[0043] The water flow carrying the sediment uses the power of the water itself as a driving force, enters the interior of the sand discharge vortex tube 5 together, and is discharged downstream along the sand discharge vortex tube 5 .

[0044] Working process: After the water flow carrying sediment enters the anti-arc surface 3, a spiral flow is formed. Part of the water flow goes back to the upstream position, and the other part of the water flow carries the sediment at the bottom into the sand discharge vortex tube 5, and is driven by the power of the water itself and discharged to the downstream.

[0045] The novel stilling pool emptying and sand discharge system of the present invention is adopted to discharge the sediment deposited at the bottom of the stilling pool, and also reduce the kinetic energy of the water flowing into the downstream, thereby reducing the scouring of the downstream by the water flow.

[0046] In some embodiments, the cross-sectional shape of the first groove is a 1 / 2 arc, so that the center of the first groove is flush with the horizontal plane of the stilling pool bottom plate 2, the cross-sectional shape of the second groove is a 1 / 4 arc, and the radius of the first groove is equal to the radius of the second groove, and the center of the first groove coincides with the center of the second groove, that is, the center of the anti-arc curved surface 3 is set to be flush with the horizontal plane of the stilling pool bottom plate 2;

[0047] The center of the reverse arc surface 3 is set to be flush with the horizontal plane of the bottom plate 2 of the energy dissipation pool. This design is conducive to the sediment deposited in the energy dissipation pool to more conveniently enter the sand discharge vortex tube 5 connected to the reverse arc surface 3, thereby facilitating the discharge of the sediment deposited, and at the same time can also reduce a part of the direct impact of the water flow on the tail sill 1, thereby improving the stability of the tail sill 1.

[0048] In some embodiments, a sand-trapping net ridge 6 is provided at the opening of the reverse curved surface 3, and two sides of the sand-trapping net ridge 6 are respectively connected to two sides of the reverse curved surface 3, and the connection here can be a fixed connection or a detachable connection;

[0049] When the two sides of the sand-trapping net ridge 6 are fixedly connected to the two sides of the anti-arc curved surface 3, they can be fixed by pouring concrete;

[0050] When the two sides of the sand-trapping net ridge 6 are detachably connected to the two sides of the anti-arc curved surface 3, screws and bolts can be used; the purpose of providing the sand-trapping net ridge 6 is to prevent sediment with too large particle size from entering the anti-arc curved surface 3, which would cause the sand discharge vortex tube 5 to be blocked.

[0051] In some embodiments, steel ribs are provided on the sand-trapping net ridge 6 to ensure the structural strength of the sand-trapping net ridge 6. Preferably, the sand-trapping net ridge 6 is made of steel bars, and the specifications of the steel bars used should be determined by the particle size and strength of the sand that is not allowed to enter the anti-arc curved surface 3. The strength of the steel bars should not be less than Ф18 to prevent the strength from being too low to be damaged by the sand.

[0052] In some embodiments, the cross-sectional shape of the sand-trapping ridge 6 is a 1 / 4 arc, the radius of the sand-trapping ridge 6 is equal to the radius of the first groove, and the lateral length of the sand-trapping ridge 6 is the same as the width of the energy dissipation pool, and the lateral spacing of the sand-trapping ridge 6 is determined according to the diameter of the sand discharge vortex tube 5.

[0053] In addition, the novel stilling pool emptying and sand removal system provided by the present invention also has the following effects:

[0054] During use, the water energy per unit area can be reduced, the scouring and damage of the water flow to the downstream riverbed and bank slope can be reduced, and the energy dissipation efficiency can be effectively improved. As the water flow goes back and counteracts the upper flow, the water flow velocity is reduced, and it is easier to form a three-dimensional bottom flow water jump energy dissipation flow state, which effectively improves the energy dissipation rate. At the same time, due to the lateral change of the bottom area of ​​the energy dissipation pool inlet water flow, the concentrated impact of the downstream water flow on the head of the energy dissipation pool can be effectively avoided, which is conducive to the stability of the energy dissipation pool bottom plate 2 and high operation safety.

[0055] The effectiveness of the new energy dissipation pool emptying and sand discharge system of the present invention has been verified by experiments. It has a simple and easy structure and is suitable for the topographic and geological conditions of narrow river valleys. It has good sand discharge effect and high energy dissipation efficiency, reduces downstream scouring, effectively improves the energy dissipation rate, uses less concrete at the tail sill 1, reduces the project cost, and has a good application prospect.

[0056] Compared with the tail sill of an ordinary energy dissipation pool, the water flow in the tail sill 1 of the energy dissipation pool of the present invention has a dynamic water pressure greater than the hydrostatic pressure, and the second conjugate water depth required to form a water jump downstream of the tail sill 1 is smaller, and it is easier to form a submerged water jump with high energy dissipation efficiency, which can effectively improve the energy dissipation rate, change the velocity distribution of the water flow out of the pool, greatly reduce the water energy per unit area, and reduce the scouring and damage of the water flow to the downstream riverbed and bank slope. At the same time, it can also be used as a discharge facility for the energy dissipation pool, which can quickly discharge the remaining water accumulated in front of the tail sill 1, which is convenient for the maintenance of the energy dissipation pool. It has outstanding advantages, simple size, low engineering cost, and has a good application prospect.

[0057] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A novel stilling pool emptying and sand removal system, comprising a stilling pool bottom plate and a tail sill, wherein the tail sill is arranged at the end of the stilling pool bottom plate, and is characterized in that: The bottom plate of the stilling pool is provided with a first groove which is concave downwards, and the length direction of the first groove is parallel to the length direction of the tail sill; The water-facing surface of the tail sill is provided with a second groove recessed toward the head end away from the bottom plate of the energy dissipation pool, the length direction of the second groove is parallel to the length direction of the tail sill, and the lower side of the second groove is connected with the side of the head end of the first groove away from the bottom plate of the energy dissipation pool to form an anti-arc curved surface; When the water carrying sediment flows from upstream to the anti-arc surface, the water will form a spiral flow in the anti-arc surface. Part of the water will flow upstream and discharge out of the anti-arc surface, and the other part of the water will carry sediment and move toward the two ends of the tail bank in the anti-arc surface and flow into the downstream.

2. The novel stilling pool emptying and sand removal system according to claim 1 is characterized by: The cross-sectional shape of the first groove is a 1 / 2 arc, the cross-sectional shape of the second groove is a 1 / 4 arc, the radius of the first groove is equal to the radius of the second groove, and the center of the first groove coincides with the center of the second groove.

3. The novel stilling pool emptying and sand removal system according to claim 2 is characterized by: A sand-trapping net ridge is arranged at the opening of the anti-arc curved surface, and two sides of the sand-trapping net ridge are respectively connected to two sides of the anti-arc curved surface.

4. The novel stilling pool emptying and sand removal system according to claim 3 is characterized by: Steel ribs are arranged on the ridges of the sand-trapping net.

5. The novel stilling pool emptying and sand removal system according to claim 4 is characterized by: The cross-sectional shape of the sand-trapping net ridge is a 1 / 4 arc, and the radius of the sand-trapping net ridge is equal to the radius of the first groove.

6. The novel stilling pool emptying and sand removal system according to claim 1 is characterized by: The radius of the first groove is greater than three times the median particle size of the sediment carried in the water flow.

7. The novel stilling pool emptying and sand removal system according to claim 1 is characterized by: The height of the tail sill is greater than 8m, and the length of the vertical section on the upper side of the second groove is not less than half of the height of the tail sill.

8. The novel stilling pool emptying and sand removal system according to claim 1 is characterized by: The height of the tail sill is less than 8m, and the length of the vertical section on the upper side of the second groove is not less than 2m.

9. The novel stilling pool emptying and sand removal system according to any one of claims 1 to 8, characterized in that: Both ends of the tail sill are provided with sand-discharging vortex tubes, the water inlet ends of the sand-discharging vortex tubes are connected to the two ends of the reverse arc surface, and the water outlet ends of the sand-discharging vortex tubes extend to the downstream.

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