Micro-lifting differential type drop sill stilling pool

Abstract

A micro-lifting differential type drop sill stilling pool is arranged at the tail end of a spillway and comprises a reverse arc caulking groove, a differential type drop sill, a stilling pool bottom plate, a stilling pool side wall and a tail sill, the upper end of the reverse arc caulking groove is connected with the spillway bottom plate in a tangent mode, and the tail end of the reverse arc caulking groove is connected with the stilling pool bottom plate through an upward lifting corner; a plurality of differential falling sills arranged in parallel are arranged above the reverse arc caulking groove, the upper surface of each differential falling sill is a horizontal plane, the starting position of each differential falling sill is smoothly connected with the spillway bottom plate through an arc, and the tail end of each differential falling sill is located on the section where the reverse arc lowest point of the reverse arc caulking groove is located; a tail sill parallel to the reverse arc caulking groove is arranged at the tail end of the stilling pool bottom plate, and the tail sill is in a reverse slope type; the stilling pool side walls are connected with the spillway side walls, and the stilling pool side walls are symmetrically arranged; and the stilling pool side wall is connected with the side edge of the tail sill. According to the utility model, the problem that the drop sill stilling basin is easy to generate surface flow under the condition of high tail water level is solved, the service life of the drop sill stilling basin is prolonged, the excavation and pouring work amount of the stilling basin is reduced, and the project investment is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of water conservancy projects, and in particular relates to a micro-lift differential drop sill energy dissipation pool. Background Art

[0002] The continuous drop-slope energy dissipation pool is the most widely used drop-slope energy dissipation pool at present. It can effectively solve the problem of large bottom flow velocity and pulsating pressure in the head of the energy dissipation pool. However, it still has the following shortcomings: First, the flow pattern in the energy dissipation pool is greatly affected by the downstream water level. When the drop-slope height is constant, as the tail water level rises, surface flow pattern is likely to appear in the energy dissipation pool, resulting in poor energy dissipation effect; second, it is difficult to determine a reasonable drop-slope height. When the drop-slope height is too low, the inflowing water is likely to directly impact the bottom plate, resulting in a large bottom flow velocity and pulsating pressure, which is likely to cause scouring damage to the bottom plate of the energy dissipation pool; third, the continuous drop-slope energy dissipation pool has a binary vortex energy dissipation, and the energy dissipation is not sufficient. A longer energy dissipation pool is required to ensure a stable water surface out of the pool, so it is not economical. Utility Model Content

[0003] In order to solve the above problems, the utility model proposes a micro-lift differential drop-slope energy dissipation pool.

[0004] A micro-cantilever differential drop sill energy dissipation pool is arranged at the end of a spillway. The spillway includes a spillway bottom plate and a spillway side wall. The feature is that it includes an anti-arc embedded groove, a differential drop sill, an energy dissipation pool bottom plate, an energy dissipation pool side wall and a tail sill. The upper end of the anti-arc embedded groove is tangentially connected to the spillway bottom plate, and the tail end of the anti-arc embedded groove is connected to the energy dissipation pool bottom plate through an upward cantilever angle; a plurality of differential drop sills arranged in parallel are arranged above the anti-arc embedded groove, the upper surface of the differential drop sills is a horizontal plane, the starting point is smoothly connected to the spillway bottom plate by a circular arc, and the end is at the section where the anti-arc lowest point of the anti-arc embedded groove is located; a tail sill parallel to the anti-arc embedded groove is arranged at the end of the energy dissipation pool bottom plate, and the tail sill is a reverse slope type; the side wall of the energy dissipation pool is connected to the side wall of the spillway, and the side wall of the energy dissipation pool is symmetrically arranged; the side wall of the energy dissipation pool is connected to the side of the tail sill.

[0005] Furthermore, the cross section of the differential drop wall perpendicular to the water flow direction is a rectangle.

[0006] The beneficial effect of the utility model is that it solves the problem that the falling sill energy stilling pool is prone to surface flow under high tailwater level conditions. Part of the water flow entering the falling sill energy stilling pool is lifted up by the reverse arc embedded groove, which greatly reduces the bottom flow velocity and pulsating pressure index of the head bottom plate of the falling sill energy stilling pool, and improves the service life of the falling sill energy stilling pool. By setting two rapidly changing shapes of differential falling sill and reverse arc embedded groove, a controllable strong turbulent three-dimensional vortex is generated, which can further improve the energy dissipation rate of the falling sill energy stilling pool, shorten the length of the energy stilling pool, reduce the excavation and pouring engineering of the energy stilling pool, and reduce the investment in the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of the three-dimensional structure of a micro-lift differential drop-slope energy dissipation pool.

[0008] Figure 2 It is a side view of a slightly elevated differential drop-slope energy dissipation pool.

[0009] Figure 3 This is a top view of a slightly elevated differential drop-slope energy dissipation pool.

[0010] Among them: 1-reverse arc groove, 2-differential drop sill, 3-energy dissipation pool bottom plate, 4-energy dissipation pool side wall, 5-tail sill, 6-spillway bottom plate, 7-spillway side wall DETAILED DESCRIPTION

[0011] Embodiment 1: A water conservancy project is a typical flood discharge project with high head and large single width flow, and conventional bottom flow stilling pool cannot meet the requirements of engineering design. Under the condition of energy dissipation and anti-scouring design flood (P=1%), the single width flow of the overflow dam surface hole is q=127.4m2 / s, the upstream water level is 1328m, the downstream water level is 1221.05m, the elevation of the top surface of the downstream protection tank is 1188m, and the width of the spillway is 87m. A micro-cantilever differential drop sill stilling pool is built at the end of the spillway, which includes an anti-arc embedded groove 1, a differential drop sill 2, a stilling pool bottom plate 3, a stilling pool side wall 4 and a tail sill 5. The spillway includes a spillway bottom plate 6 and a spillway side wall 7, the upper end of the anti-arc embedded groove 1 is tangently connected to the spillway bottom plate 6, and the tail end of the anti-arc embedded groove 1 is connected to the stilling pool bottom plate 3 through an upward cantilever angle, and the cantilever angle is between 5° and 25°. The length of the stilling pool bottom plate 3 is L, L = (0.6 ~ 0.7) L j , where L j The water jump length is the free water jump length, L j =10.8h1(F r1 -1) 0.93 , F r1 is the Froude number at the end of the drop. The length L of the stilling pool bottom plate 3 in this embodiment is 140m.

[0012] A plurality of differential drop sills 2 are arranged in parallel above the anti-arc embedded groove 1. The upper surface of the differential drop sill 2 is a horizontal plane. The starting point is smoothly connected to the spillway bottom plate 6 by an arc, and the end is at the section where the anti-arc lowest point of the anti-arc embedded groove 1 is located. The drop height of the differential drop sill 2 is s, and the drop height s is estimated according to the following formula:

[0013]

[0014] Where s is the height of the drop (m), H is the elevation difference from the upstream water surface to the top of the drop (m), q is the flow rate per unit width of the stilling pool (m2 / s), and U is bmax is the maximum allowable bottom flow velocity (m / s). bmax=15m / s, the height of the drop s is calculated to be 8m. The arc radius at the connection between the spillway bottom plate 6 and the differential drop 2 is r, r=s / 2, which is 4m in this embodiment; the cross section of the differential drop 2 perpendicular to the water flow direction is a rectangle.

[0015] The arc radius of the reverse arc groove 1 is R, which is between 4h1 and 20h1. h1 is the average water depth of the end section of the drop bank during the design flood. A larger R value should be used when the flow rate is large. h1 can be calculated as follows:

[0016]

[0017] Where ΔH is the elevation difference from the upstream water surface to the bottom plate of the stilling pool (m); is the flow rate coefficient, In this embodiment, h1 = 2.80 m. The width of the differential step 1 is b1 = s, and the step spacing is b2, b2 = b1 ~ 1.5 b1, in this embodiment, b1 = 8 m, b2 = 1.47 b1 = 11.75 m.

[0018] The end of the stilling pool bottom plate 3 is provided with a tail sill 5 parallel to the reverse arc embedded groove 1, the tail sill 5 is a reverse slope type, the stilling pool side wall 4 is connected to the spillway side wall 7, the stilling pool side wall 4 is symmetrically arranged; the stilling pool side wall 4 is connected to the side of the tail sill 5. The reverse slope gradient is set to 1:n, n is between 0 and 3, the tail sill height is c, c=(2.0~3.0)s, in this embodiment c=12, and the reverse slope gradient is set to 1:2.

Claims

1. A micro-lift differential drop-slope energy dissipation pool is arranged at the end of a spillway, wherein the spillway includes a spillway bottom plate and a spillway side wall, and is characterized in that: It includes an anti-arc embedded groove, a differential drop sill, an energy dissipation pool bottom plate, an energy dissipation pool side wall and a tail sill. The upper end of the anti-arc embedded groove is tangentially connected to the spillway bottom plate, and the tail end of the anti-arc embedded groove is connected to the energy dissipation pool bottom plate through an upward angle. A plurality of differential drop sills arranged in parallel are arranged above the anti-arc embedded groove. The upper surface of the differential drop sills is a horizontal plane. The starting point is smoothly connected to the spillway bottom plate with an arc, and the end is at the section where the anti-arc of the anti-arc embedded groove is located. A tail sill parallel to the anti-arc embedded groove is arranged at the end of the energy dissipation pool bottom plate, and the tail sill is a reverse slope type. The side wall of the energy dissipation pool is connected to the side wall of the spillway, and the side walls of the energy dissipation pool are symmetrically arranged. The side wall of the energy dissipation pool is connected to the side of the tail sill.

2. A micro-lift differential drop-slope energy dissipation pool as claimed in claim 1, characterized in that The cross section of the differential drop sill perpendicular to the water flow direction is a rectangle.

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