Convex flip bucket

Abstract

The invention provides a convex flip bucket which comprises a first-stage flip bucket and a second-stage flip bucket, and the first-stage flip bucket is a transverse diffusion type flip bucket and comprises a discharge chute bottom plate expanding in the water flow direction and side walls on the two sides; the secondary flip bucket is a convex tooth flip bucket without a side wall; the convex tooth flip bucket without a side wall is directly connected to the outlet end of the transverse diffusion type flip bucket, and the width of the convex tooth flip bucket is gradually reduced in the water flow direction, so that high-speed water flow passing through the convex flip bucket is flown out from different positions and different elevations, the water tongue going out of the bucket is fully diffused in the longitudinal direction and the transverse direction, and the water flow is uniform. The actual water inlet width of discharged water flow is larger than that of a conventional flip bucket, the actual water inlet single-width flow of the nappe is reduced, and the flushing and washing effect of the incident water flow on a riverbed bottom plate and the bank side is relieved.

Description

Technical Field

[0001] The invention belongs to the technical field of water conservancy projects, and in particular relates to a convex flow nose sill. Background Art

[0002] Energy dissipation by diverting flow refers to setting up different forms of diverting nose sills at the end of the spillway of the water discharge structure, using the huge kinetic energy of the downstream water flow, that is, the flow velocity, to divert the high-speed water flow into the air, and then drop it into the river channel far away from the building. As the water flow loses the restraint of the solid boundary, it first loses a small part of the kinetic energy under the action of turbulence and air resistance, and most of the energy is consumed by the water tongue after entering the downstream water body, colliding and mixing with the downstream water body, and the viscosity of the water, under the action of strong shear and strong turbulence, the kinetic energy is converted into heat energy. When the river valley is narrow, the bottom slope is steep, the discharge volume is large, and the downstream water cushion is shallow, the water flow transported by the diverting nose sill in the existing technology will seriously scour the downstream riverbed and bank slope. Therefore, it is urgent to design a diverting nose sill so that the downstream water flow can be spread as much as possible, reduce the single-width flow of the downstream discharge, and improve the energy dissipation rate to reduce the depth of the downstream scouring pit and the amount of protective engineering. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a convex flow nose sill which can diffuse the downstream water flow from the upstream as much as possible and has the advantages of simple structure and sufficient vertical and horizontal diffusion of the water tongue at the sill.

[0004] The present invention discloses a convex sill connected to the spillway, comprising a primary sill and a secondary sill;

[0005] The first-level sill includes a chute bottom plate that expands along the water flow direction and side walls on both sides;

[0006] The secondary sill has no side wall, the width of the secondary sill is smaller than the outlet width of the primary sill, and the width of the secondary sill gradually shrinks along the direction of water flow;

[0007] The first-level embankment is connected to the second-level embankment to form three-dimensional dispersed outlets with different elevations and different plane positions, so as to realize the lateral and longitudinal diffusion of the water tongue behind the embankment.

[0008] The convex flow nose sill provided by the present invention directly connects a convex tooth sill without side wall to the outlet end of the sill that diffuses laterally on the bottom plate of the chute. The width of the convex tooth sill gradually shrinks along the direction of the water flow, so that the high-speed water flow passing through the convex flow nose sill cantilevers out from different positions and different elevations, and the water tongue at the outlet of the sill diffuses fully longitudinally and laterally. The actual water inlet width of the downstream water flow is wider than that of the conventional sill, which reduces the actual water inlet single-width flow of the water tongue and reduces the scouring effect of the incident water flow on the riverbed bottom plate and the bank.

[0009] Furthermore, the secondary sill is tangentially connected to the chute bottom plate to achieve a curved surface transition to ensure smooth water flow along the way, thereby reducing the risk of cavitation and erosion of the convex sill.

[0010] Furthermore, the distance B between the secondary sill and the left wall of the primary sill exit is 1 and the distance B between the secondary sill and the right wall of the primary sill exit 3 The size is: B 1 B 3 The left contraction angle β of the secondary pick 1 The value range is [5°, 10°], and / or, the right side contraction angle β of the secondary ridge 2 The value range is [5°, 10°]. According to the terrain and geological conditions of the downstream river channel, the connection position between the secondary sill and the primary sill and the direction of the water tongue can be flexibly adjusted in the center or left; the left and center settings of the secondary sill correspond to different shapes of the diverted water tongue, and the offset water tongue and the symmetrical water tongue have different energy dissipation effects; the connection position between the secondary sill and the primary sill combined with the side contraction angle β of the secondary sill is used to control the water tongue landing point to adapt to the different geological conditions of the downstream river channel.

[0011] Furthermore, the distance B between the secondary sill and the left wall of the primary sill exit is 1 and the distance B between the secondary sill and the right wall of the primary sill exit 3 The size is: B 1 >B 3 The left contraction angle β of the secondary pick 1 The value range is [5°, 10°], and / or, the right side contraction angle β of the secondary ridge 2 The value range of is [5°, 10°]. According to the terrain and geological conditions of the downstream river channel, the connection position between the secondary sill and the primary sill and the direction of the water tongue can be flexibly adjusted to the right; the secondary sill is set to the right to correspond to different shapes of diverted water tongues, and the diverted water tongue and the symmetrical water tongue have different energy dissipation effects; the connection position between the secondary sill and the primary sill combined with the lateral contraction angle β of the secondary sill is used to control the water tongue landing point to adapt to the different geological conditions of the downstream river channel.

[0012] Furthermore, the value range of the first-level cantilever angle θ is [-30°, 30°]; different types of first-level cantilever can be selected according to different engineering conditions, such as: reverse arc cantilever type, flat cantilever type and depression angle cantilever type. At the same time, in order to cooperate with the second-level cantilever to make the water tongue effectively cantilever and fully diffuse, the absolute value of the maximum cantilever angle shall not exceed 30°.

[0013] Furthermore, the outlet width of the first level ridge is , where b is the width of the spillway before the cantilever, L1 is the length of the first-level ridge, α 1 is the diffusion angle of the left wall of the first-level cantilever, α 2 It is the diffusion angle of the right wall of the first-level cantilever.

[0014] Furthermore, the diffusion angle α of the left wall of the first-level ridge is 1 The value range is [0°, 7°]; and / or, the diffusion angle α of the right wall of the first-level sill 2 The value range of is [0°, 7°]. The diffusion angle is set to ensure that the water does not impact the downstream slope after flowing out of the bank.

[0015] Furthermore, the angle difference between the secondary ridge and the primary ridge is ,in, is the maximum downstream flow rate, and B is the outlet width of the first-level embankment.

[0016] Furthermore, the horizontal length of the secondary ridge is .

[0017] Furthermore, the starting width of the secondary ridge is .

[0018] Furthermore, the width of the second level ridge end is .

[0019] The present invention has the following beneficial effects:

[0020] The convex flow nose sill provided by the present invention has a simple structure and a low risk of cavitation erosion. The water tongue at the sill can fully diffuse in the longitudinal and transverse directions, thereby increasing the braking ability of the downstream water body to the high-speed downstream water flow, reducing the downstream scouring depth and hydraulic parameters, alleviating the difficulty of downstream energy dissipation and anti-scouring, ensuring project safety, reducing the amount of downstream protection projects, and saving project construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a cross-sectional structure of a convex flow nose provided in some embodiments of the present invention,

[0022] Figure 2 It is a schematic diagram of the planar structural arrangement of a convex flow nose provided in some embodiments of the present invention;

[0023] Description of reference numerals:

[0024] 1 spillway, 2 spillway side wall, 3 first-level sill, 3-1 chute bottom plate, 3-2 side wall, 4 second-level sill, 5 downstream river channel, 6 downstream river channel scouring pit, 7 water tongue, 8 water tongue drop area,

[0025] The width of the spillway before the cantilever is b; the angle difference between the secondary cantilever and the primary cantilever is △θ;

[0026] First-level cantilever body parameters: First-level cantilever side wall height h 导 ; Diffusion angle α of the left wall of the first-level cantilever 1 ; Diffusion angle α of the right wall of the first-level cantilever 2 ; Length of first level sill L 1 ; The radius of the first-level arc R 1 ; The first-level cantilever angle θ; The vertical water depth of the first-level cantilever top h 1 ; Width of first-level sill exit B;

[0027] Secondary sill size parameters: The distance B between the secondary sill and the left wall of the primary sill exit 1 ; Secondary pick width B 2 ; The distance B between the second level sill and the right wall of the first level sill exit 3 ; Secondary ridge end width B 4 ; Secondary ridge length L; Secondary ridge left contraction angle β 1 ; Secondary right side contraction angle β 2 ; Secondary pick-up arc radius R 2 ;

[0028] First level sill top water head H 0 ; Upstream and downstream water level difference H; height difference between the top of the first-stage cantilever sill and the downstream water surface h 2 ; Downstream water depth h t ; Downstream scour depth T. DETAILED DESCRIPTION

[0029] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention. Terms such as "inside", "outside", "upper", "lower", "top", "bottom", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0030] The present invention provides a convex ridge nose, connected to the spillway 1, including a primary ridge 3 and a secondary ridge 4, the primary ridge 3 includes a chute bottom plate 3-1 and a side wall 3-2, the chute bottom plate 3-1 is connected to the spillway bottom plate, and the side wall 3-2 is connected to the spillway side wall 2. The primary ridge 3 is a transverse diffusion type ridge, the chute bottom plate expands along the water flow direction so that the water flow is diffused laterally along the chute. The main body parameters of the primary ridge 3 are the diffusion angle α of the left wall 1 and the diffusion angle α of the right wall 2 , first level ridge length L 1 , outlet width B, cantilever angle θ and side wall height h 导 The process of determining the body parameters of the first level challenge 3 is as follows:

[0031] Diffusion angle α of the left wall of the first-level sill 1 The value range is [0°, 7°], and / or, the diffusion angle α of the right wall of the first-level sill 2 The value range is [0°, 7°]. The diffusion angle is set to ensure that the water does not impact the downstream slope after flowing out of the bank. When the bank flow velocity is greater than 30m / s, the diffusion angle should be less than 5°.

[0032] The width B of the first-stage cantilever exit is determined by the engineering conditions and the diffusion angle α of the left and right walls of the first-stage cantilever. 1 and α 2 Sure:

[0033] (1)

[0034] The value range of the first-level cantilever angle θ is [-30°, 30°]. For example, the first-level cantilever 3 can adopt one of the three forms of reverse arc cantilever type, flat cantilever type and depression angle cantilever type to adapt to different engineering conditions; at the same time, in order to cooperate with the second-level cantilever 4 to make the water tongue effectively cantilever and fully diffuse, the absolute value of the maximum cantilever angle shall not exceed 30°.

[0035] First level cantilever side wall 3-2 height h 导 Determined according to the requirements of the current spillway design specifications (see Spillway Design Specifications (SL253-2018) or Spillway Design Specifications (NB / T 10867-2021) for details).

[0036] According to the engineering conditions and downstream geological conditions, and on the premise of ensuring the safety of the project, the downstream scour depth T is initially planned. 设 , and according to the calculation formula of the pit depth recommended by the current specification, the depth that satisfies T 设 The water inlet flow rate q 入设 : (2)

[0037] Where: h tis the downstream water depth, m; H is the upstream and downstream difference, m; K is the bedrock scour coefficient.

[0038] The secondary sill 4 is located immediately after the primary sill 3. It is a convex tooth sill without side walls. It forms a single convex tooth shape outside the primary sill 3. The width of the convex tooth sill gradually shrinks along the direction of water flow. The main body parameters of the secondary sill 4 are the distance B between the secondary sill 4 and the left and right walls of the primary sill 3 outlet. 1 and B3, the width of the starting end of the secondary pick 2 , Width B of the end of the secondary ridge 4 、Secondary ridge left side contraction angle β 1 、Secondary right side contraction angle β 2 , the length of the secondary ridge L, the angle difference between the secondary ridge and the primary ridge △θ, the radius of the secondary ridge arc R 2 , the horizontal surface area A of the secondary ridge, the body parameter determination process of the secondary ridge 4 is as follows:

[0039] The distance between the left wall of the secondary sill 4 and the primary sill 3 exit is B1, and the distance between the right wall of the secondary sill 4 and the primary sill 3 exit is B 3 The size is: B 1 <B 3 , or B 1 =B 3 , or B 1 >B 3 According to the terrain and geological conditions of the downstream river channel, the connection position of the secondary sill 4 and the primary sill 3 can be flexibly adjusted to the center, left or right; is the maximum discharge flow, B is the outlet width of the first-level embankment 3;

[0040] Secondary pick 4 starting end width B 2 : (3)

[0041] Horizontal length L of secondary ridge 4: (4)

[0042] Secondary ridge 4 left and right contraction angle β 1 and β 2 The value range is between 5°-10°. When the flow rate of the picket is larger, the contraction angle β on the left and right sides of the secondary picket 4 will be larger. 1 and β 2 The larger the value of ;

[0043] Secondary ridge 4 end width B 4 : (5)

[0044] The angle difference △θ between the secondary pick 4 and the primary pick 3: (6)

[0045] Based on the shape of the first-level ridge 3, according to the shape parameters L and △θ of the second-level ridge 4, the radius R of the second-level ridge anti-arc is calculated. 2 .

[0046] Verify the rationality of the preliminary design of the secondary ramp 4:

[0047] Calculate the water entry width C of the convex nose water tongue in the preliminary design 入 : (7) (8) (9) (10) (11)

[0048] Where: γ is the diffusion coefficient of the convex flow nose water tongue; L 距 is the horizontal distance between the outer edge of the first-stage overhang water tongue and the intersection of the downstream water surface, m; v is the flow velocity at the top of the first-stage overhang, m / s; h is the horizontal distance between the outer edge of the first-stage overhang water tongue and ... 1 is the vertical water depth of the first-stage cantilever top, m; the height difference between the first-stage cantilever top and the downstream water surface, h 2 , m.

[0049] Calculate the water inlet flow rate per width q of the preliminary designed convex sill 入 : (12)

[0050] when , then the body design is reasonable; otherwise, by appropriately increasing B 2 , L, △θ to meet the design requirements.

[0051] The convex flow nose sill provided by the present invention will be specifically described below by taking a hydropower project as an example.

[0052] Example 1

[0053] The water depth of the downstream river channel 5 of a hydropower project is shallow and the geological conditions are poor. In order to reduce the scope and depth of downstream scouring and reduce the amount of protective engineering, a convex nose sill is used at the end of the discharge structure, such as Figure 1 , Figure 2 As shown, the convex flow nose sill of this example is composed of a first-level sill 3 with a diffusion side wall 3-2 at the outlet section of the spillway 1 and a second-level sill 4 without a side wall. In the figure, there is a downstream river channel 5, a downstream river channel scouring pit 6, a flow-propelling water tongue 7 and a water tongue drop area 8.

[0054] The maximum discharge flow of the spillway of this project The flow rate is 478m³ / s, the width b of the spillway upstream of the nose sill is 5.00m, the height of the spillway side wall 2 is 5.50m, and the upstream and downstream water level difference H is 87.10m. According to the present invention, the plane design of the first-stage sill section is a diffusion type, and the left and right walls 3-2 diffuse symmetrically to both sides, and the diffusion angle α 1 , α 2 The angles of the discharge chute at the end of the first-stage cantilever section are both 2.985°. The width of the discharge chute at the end of the first-stage cantilever section is 9.00m. The radius of the reverse arc of the first-stage cantilever section is R 1 is 70.00m, the cantilever angle θ is 20.786°, the cantilever top elevation is 162.00m, and the cantilever top water head H 0 is 72.60m, and the height difference between the top of the embankment and the downstream water surface is h 2 14.50m; downstream water depth h t The downstream scour depth T is set to 8.00 m based on the engineering boundary and geological conditions. The inlet flow rate q that satisfies T is obtained according to formula (2): 入设 9.24m³ / (s·m); the two sides of the secondary ridge 4 are designed to shrink symmetrically, with a shrinkage angle of β 1 and β 2 Take 5° for both angles, and according to formula (3) to formula (6), the starting width B of the secondary pick is obtained. 2 is 4.74m, the length of the secondary embankment L is 5m, and the width of the end of the secondary embankment B 4 is 3.87m, and the angle difference △θ is 5.421°; according to R 1 , L, θ and △θ, calculate the radius R of the secondary pick-up arc 2 58.99m; the secondary sill 4 is arranged in the center, and the distance from the left and right side walls of the primary sill 3 exit is B 1 and B 3 The water entry width C of the convex nose sill water tongue of the preliminary design is obtained by using formulas (7) to (11) according to the body parameters of the first-level sill 3 and the second-level sill 4. 入 is 55.11m, and the single-width inlet flow rate q of the initial design is obtained by formula (12): 入 =8.67m³ / (s·m), less than q 入设 The value is 9.24m³ / (s·m), and the convex cantilever shape meets the design requirements.

[0055] The results of the 1:50 hydraulic model test show that the convex flow nose water tongue provided in this embodiment has sufficient longitudinal and lateral diffusion, and the water inlet width C is 478 m³ / s when the maximum discharge flow is 478 m³ / s. 入The maximum depth of the downstream scour is 51.80m, and the measured maximum depth of the downstream scour is 7.47m, which is 6.38m shallower than the 13.85m when there is only one level of embankment. This reduces the impact of downstream scour on project safety and river slope stability, reduces the amount of downstream protection projects, and reduces project investment.

[0056] Example 2 The distance B between the left wall of the secondary sill and the primary sill exit 1 The distance B between the second level sill and the right wall of the first level sill exit 3 The size is: B 1 >B 3 , the left contraction angle of the secondary ridge β 1 The value range is [5°, 10°], and the right contraction angle β of the secondary ridge 2 The value range of is [5°, 10°]. According to the terrain and geological conditions of the downstream river channel, the connection position between the secondary sill and the primary sill and the direction of the water tongue can be set to the right; the secondary sill is set to the right to correspond to different shapes of diverted water tongues, and the diverted water tongue and the symmetrical water tongue have different energy dissipation effects; the connection position between the secondary sill and the primary sill combined with the lateral contraction angle β of the secondary sill is used to control the water tongue landing point to adapt to the different geological conditions of the downstream river channel.

[0057] Example 3 The distance B between the left wall of the secondary sill and the primary sill exit 1 The distance B between the second level sill and the right wall of the first level sill exit 3 The size is: B 1 <B 3 , the left contraction angle of the secondary ridge β 1 The value range is [5°, 10°], and the right contraction angle β of the secondary ridge 2 The value range is [5°, 10°]. According to the terrain and geological conditions of the downstream river channel, the connection position between the secondary sill and the primary sill and the direction of the water tongue can be set to the left; the secondary sill is set to the left to correspond to different shapes of diverted water tongues, and the diverted water tongue and the symmetrical water tongue have different energy dissipation effects; the connection position between the secondary sill and the primary sill combined with the lateral contraction angle β of the secondary sill is used to control the water tongue landing point to adapt to the different geological conditions of the downstream river channel.

[0058] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A convex nose sill connected to a spillway (1), characterized in that: It includes a first-level pick-up sill (3) and a second-level pick-up sill (4); The first-level embankment (3) comprises a chute bottom plate (3-1) that expands along the water flow direction and side walls (3-2) on both sides; The secondary sill (4) has no side wall, the width of the secondary sill (4) is smaller than the outlet width of the primary sill, and the width of the secondary sill (4) gradually shrinks along the direction of water flow; The outlet end of the first-stage sill (3) is connected to the second-stage sill (4) to form three-dimensional dispersed outlets at different elevations and different plane positions, thereby achieving lateral and longitudinal diffusion of the water tongue behind the sill.

2. The convex nose ridge according to claim 1, characterized in that: The secondary ledge (4) is tangentially connected to the chute bottom plate (3-1) to achieve smooth connection.

3. The convex nose ridge according to claim 1, characterized in that: The distance B1 between the secondary sill (4) and the left wall of the primary sill (3) and the distance B3 between the secondary sill and the right wall of the primary sill are: B1 B3; the value range of the left contraction angle β1 of the secondary ridge (4) is [5°, 10°], and / or the value range of the right contraction angle β2 of the secondary ridge (4) is [5°, 10°].

4. The convex nose ridge according to claim 1, characterized in that: The distance B1 between the secondary ridge (4) and the left wall of the primary ridge (3) outlet and the distance B3 between the secondary ridge and the right wall of the primary ridge outlet are: B1>B3; the left contraction angle β1 of the secondary ridge (4) has a value range of [5°, 10°], and / or the right contraction angle β2 of the secondary ridge (4) has a value range of [5°, 10°].

5. The convex nose ridge according to claim 1, characterized in that: The value range of the angle θ of the first-level step (3) is [-30°, 30°].

6. The convex nose ridge according to claim 1, characterized in that: The outlet width of the first level ridge (3) , where b is the width of the spillway before the cantilever, L1 is the length of the first-stage cantilever (3), α1 is the diffusion angle of the left wall of the first-stage cantilever (3), and α2 is the diffusion angle of the right wall of the first-stage cantilever (3).

7. The convex nose ridge according to claim 1, characterized in that: The diffusion angle α1 of the left wall of the first-level ridge (3) has a value range of [0°, 7°]; and / or the diffusion angle α2 of the right wall of the first-level ridge (3) has a value range of [0°, 7°].

8. The convex nose ridge according to claim 1, characterized in that: The difference in angle between the secondary ridge (4) and the primary ridge (3) ,in, is the maximum discharge flow, and B is the outlet width of the first-stage embankment (3).

9. The convex flow-rising nose ridge according to any one of claims 1 to 8, characterized in that: The horizontal length of the secondary ridge (4) .

10. The convex nose ridge according to claim 9, characterized in that: The starting width of the secondary pick (4) .

11. The convex nose ridge according to claim 9, characterized in that: The width of the end of the secondary ridge (4) .

Images