A swirl shaft type energy dissipation structure

Abstract

The present invention discloses a vortex shaft type energy dissipation structure, comprising an upper flat section, a vortex shaft, and a lower flat section. The upper end of the vortex shaft is connected to the external environment through an inlet hole, and the lower end of the vortex shaft is connected to the external environment through an outlet hole. The inlet hole port serves as a flow channel inlet, and the outlet hole port serves as a flow channel outlet. By adopting the technical solution of the present invention, after the fluid is fed into the flow channel inlet, when the fluid flow rate or flow velocity is small, the fluid directly enters the vortex shaft and flows in a vortex manner, dissipating most of the energy therein; when the fluid flow rate or flow velocity is large, part of the fluid passes through the vortex shaft and hits the energy dissipation wall at the port of the vortex shaft, dissipating part of the water flow energy through the energy dissipation wall, and the reflected backflow water body continuously collides and mixes with the upstream water flow in the vortex shaft, and flows out after dissipating the energy in the water body again, so that the fluid reduces the hydraulic impact on downstream buildings and facilities, protects the structural safety of the building, and reduces the risk of engineering operation.

Description

Technical Field

[0001] The present invention specifically relates to the technical field of flow channel flood discharge and energy dissipation in water conservancy and hydropower projects, and in particular to a vortex shaft type energy dissipation structure. Background Art

[0002] As a flow channel in a water conservancy and hydropower project, in addition to meeting flood discharge capacity requirements, it must also ensure the safety of flood discharge structures during operation, maintain good connection with the original river flow, and fully utilize its energy dissipation effect to prevent the downstream water flow from scouring and damaging the downstream riverbed and bank slopes. An energy dissipation flow channel is a device that designs a number of energy dissipators of different shapes and structures on the flow channel surface to increase the roughness of the water flow wall. The flow is then heavily aerated to increase the capacity loss along the flow during the discharge process, reducing the downstream energy dissipation pressure. At the same time, the flow channel wall is aerated to reduce cavitation damage and ensure the safe operation of the discharge structure. In the existing technology, the design concept of the energy dissipation channel is generally as follows: the water flows through the slow flow section, is accelerated after passing through the steep trough section, and then dissipates energy through the energy dissipator. This traditional energy dissipation method has a long water flow acceleration process and a long section that may cause cavitation damage, which is not conducive to project safety. At the same time, the bottom plate of the chute is smooth and there are no energy dissipation measures. The energy of the discharged water flow is large, and the energy dissipation depends solely on the energy dissipator. This places high requirements on the design and construction of the energy dissipator-related facilities, and the construction project investment and construction costs are high. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a swirl shaft type energy dissipation structure.

[0004] The present invention is achieved through the following technical solutions.

[0005] The present invention provides a vortex shaft type energy dissipation structure, comprising a vortex shaft, wherein the upper end of the vortex shaft is connected to the external environment through an upper flat section, and the lower end of the vortex shaft is connected to the external environment through a lower flat section. The port of the upper flat section serves as a flow channel inlet, and the port of the lower flat section serves as a flow channel outlet.

[0006] An energy dissipation wall is further provided downstream of the upper end port of the swirl shaft, and the energy dissipation wall and the upper flat section opening are opposite to each other.

[0007] The cross-sections of the upper flat section and the lower flat section are one of an open channel section, a city gate tunnel section, a circle, and a horseshoe shape.

[0008] An inlet weir head is provided at the inlet of the flow channel.

[0009] The swirl shaft is arranged at a position close to the flow channel inlet or the flow channel outlet.

[0010] A water cushion and a lining structure are provided at the bottom of the cyclone shaft.

[0011] The length of the entrance hole is greater than 1 times the hole diameter.

[0012] The swirl shaft is circular, elliptical, or has a smooth and gradually curved cross section.

[0013] There is one flow channel, and one swirl shaft and one water cushion are arranged or multiple are arranged alternately.

[0014] There may be multiple flow channels, with multiple vortex shafts arranged between the multiple parallel flow channels, and the lower water cushions connected into one. Multiple vortex shafts and water cushions may also be arranged alternately.

[0015] The beneficial effects of the present invention are as follows: by adopting the technical solution of the present invention, the fluid fed into the flow channel inlet first enters the vortex shaft when flowing through the flow channel surface in the inlet hole, and flows in the vortex shaft in a vortex manner, thereby dissipating most of the energy in the fluid and reducing the hydraulic impact of the fluid on downstream facilities. The water flow after dissipation in the vortex shaft then flows out of the outlet hole, making the flow direction of the fluid tend to be unified again, thereby improving the hydraulic conditions of the water flow. In addition, when the water flow rate at the inlet hole is large, a part of the water flow will pass through the vortex shaft and hit the energy dissipation wall at the end of the vortex shaft, and the energy dissipation wall can also dissipate part of the water flow energy. In addition, the vortex shaft is connected to the external environment atmosphere through the air supply pipe, so that the vortex shaft maintains good ventilation, which can further accelerate the flow velocity and turbulence of the water flow in the vortex shaft, making the effect of dissipating the fluid energy more significant. The present invention has the advantages of simple structure, convenient construction, low project cost, etc., and is suitable for wide promotion and application in the field of water conservancy and hydropower engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] Figure 2 It is a structural diagram of embodiment 1 of the present invention;

[0018] Figure 3 It is a structural diagram of the second embodiment of the present invention;

[0019] Figure 4 It is a cross-sectional view taken along line AA of a second embodiment of the present invention.

[0020] Middle: 1- inlet hole, 2- swirl shaft, 3- outlet hole, 4- air supply pipe, 5- energy dissipation wall, 11- flow channel inlet, 12- inlet weir head, 21- water cushion, 31- flow channel outlet. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but the scope of protection claimed is not limited to the description.

[0022] A swirl shaft type energy dissipation structure of the present invention, such as Figures 1 to 4 As shown, it includes a vortex shaft 2, the upper end of the vortex shaft 2 is connected to the external environment through the upper flat section 1, and the lower end of the vortex shaft 2 is connected to the external environment through the lower flat section 3. The port of the upper flat section 1 serves as the flow channel inlet 11, and the port of the lower flat section 3 serves as the flow channel outlet 31.

[0023] By adopting the technical solution of the present invention, the fluid fed into the flow channel inlet first enters the vortex shaft when flowing through the flow channel surface in the inlet hole, and flows in the vortex shaft in the form of a vortex, thereby dissipating most of the energy in the fluid and reducing the hydraulic impact of the fluid on downstream facilities. The water flow after dissipation in the vortex shaft flows out from the outlet hole, so that the flow direction of the fluid tends to be unified again, thereby improving the hydraulic conditions of the water flow. In addition, when the water flow rate at the inlet hole is large, a part of the water flow will pass through the vortex shaft and hit the energy dissipation wall at the end of the vortex shaft, and part of the water flow energy can also be dissipated by the energy dissipation wall. In addition, the vortex shaft is connected to the external environment atmosphere through the air supply pipe, so that the vortex shaft maintains good ventilation, which can further accelerate the water flow velocity and turbulence in the vortex shaft, making the effect of dissipating fluid energy more significant. The present invention has the advantages of simple structure, convenient construction, low project cost, etc., and is suitable for wide promotion and application in the field of water conservancy and hydropower engineering.

[0024] Furthermore, an energy dissipation wall 5 is provided at the upper end port of the vortex shaft 2, and the energy dissipation wall 5 is opposite to the entrance hole 1. The energy dissipation wall 5 is made of concrete. When the water flow rate at the entrance hole is large, a part of the water flow will pass over the vortex shaft and hit the energy dissipation wall at the end of the vortex shaft. The energy dissipation wall can also dissipate part of the energy of the water flow, further improving the hydraulic conditions of the water flow. The specific position of the energy dissipation wall 5 can be determined by hydraulic numerical calculation or physical model test, so that the reflected water flow can fall into the shaft after the flow velocity drops slightly, or the reflected water flow can fall into the shaft together after the energy dissipation of the upstream flow through reflection.

[0025] Furthermore, it is preferred that the cross section of the outlet hole 3 is one of an open channel section, a city gate section, a circle, and a horseshoe shape. The outlet hole 3, the cross section of the outlet hole 3 is one of an open channel section, a city gate section, a circle, and a horseshoe shape.

[0026] It is preferred that the vortex shaft 2 is set close to the flow channel inlet 11. This ensures that the outlet water flow velocity is as small as possible. Alternatively, the vortex shaft (2) is set close to the flow channel inlet (11) to ensure that most of the energy in the flow channel is dissipated in the initial stage, ensuring the safe operation of the structure of the flow channel downstream of the vortex shaft. This allows the fluid entering from the flow channel inlet 11 to enter the vortex shaft 2 in a relatively short time to dissipate its energy, thereby accelerating the energy dissipation processing speed, preventing the entrance hole 1 from being scoured due to the large energy in the water flow, and ensuring the safety of the entrance hole 1. The specific position and size of the vortex shaft 2 can be determined by hydraulic numerical calculation or physical model test and comprehensive consideration of construction technology to ensure that the reflected water flow can fall into the shaft after the flow velocity drops slightly, or the reflected water flow can fall into the shaft together after the energy is dissipated by reflection and collision with the upstream flow. The depth of the vortex shaft 2 should be as close as possible to the outlet elevation of the bottom hole section to reduce the water flow velocity at the rear of the shaft and avoid scouring and damage to the buildings downstream of the shaft.

[0027] Furthermore, a water cushion (21) is provided at the bottom of the vortex shaft (2), and the size, lining structure, and depth of the water cushion need to be determined according to the specific project through hydraulic calculations and physical model tests. The layout position, structural size, and lining structure of the vortex shaft type energy dissipation structure need to be determined according to the specific project through hydraulic calculations and physical model tests.

[0028] Furthermore, an inlet weir 12 is preferably provided at the flow channel inlet 11. This weir 12 also dissipates some of the energy in the water flow, further improving the hydraulic conditions of the water flow. A water cushion 21 is provided at the bottom of the vortex shaft 2 to offset the energy of falling water and provide adequate protection for the vortex shaft floor. The specific thickness of the water cushion 21 can be demonstrated through hydraulic numerical calculations or physical model testing.

[0029] In addition, the vortex shaft (2) is circular, elliptical, or has a smooth and gradually changing curved cross section. The cross section of the vortex shaft can be a single cross section or a multi-section structure with a large upper section and a small lower section, or a small upper section and a large lower section with a smooth and gradually changing transition. There are sufficient air supply holes 4 facilities connected to the entrance hole 1 and the vortex shaft 2, respectively, to provide sufficient ventilation and air supply conditions to avoid cavitation and erosion damage in the area where the water flow changes drastically. The inlet of the vortex shaft 2 can form a downward-reducing trumpet-shaped cross section to ensure that the water flow falls within the maximum range. The bottom of the energy dissipation wall 5 should be chamfered to avoid the water flow forming a cavity at this part and cavitation. The water cushion 21 at the bottom of the vortex shaft 2 can also adopt a variety of energy dissipation methods similar to the bottom flow energy dissipation and form two weirs 6 downstream to reduce the excavation of the energy dissipation pool while meeting the thickness of the water cushion 21.

[0030] Furthermore, several air supply pipes 4 are installed on the inner wall of the cyclone shaft 2, connecting to the external atmosphere. This provides adequate ventilation and air supply, preventing cavitation damage in areas with drastic flow fluctuations. Using the technical solution of the present invention, the outflow velocity at the flow channel outlet 13 is approximately 3 to 5 m / s, significantly reducing the fluid velocity and significantly dissipating the energy in the fluid.

Claims

1. A swirl shaft type energy dissipation structure, characterized by: The invention comprises a swirl shaft (2), wherein the upper end of the swirl shaft (2) is connected to the external environment through an upper flat section (1), and the lower end of the swirl shaft (2) is connected to the external environment through a lower flat section (3); the port of the upper flat section (1) serves as a flow channel inlet (11), and the port of the lower flat section (3) serves as a flow channel outlet (31); an energy dissipation wall (5) is further provided downstream of the upper end port of the swirl shaft (2), and the energy dissipation wall (5) is connected to the opening of the upper flat section (1). Opposite to each other, an inlet weir head (12) is provided at the inlet of the flow channel (11), a water cushion (21) is provided at the bottom of the vortex shaft (2), the length of the upper flat section (1) is greater than 1 times the hole diameter, the flow channel is one, the vortex shaft (2) and the water cushion (21) are arranged in one, the water flow from the upper flat section (1) passes over the vortex shaft, hits the energy dissipation wall (5) at the port of the vortex shaft, and dissipates part of the energy of the water flow through the energy dissipation wall (5).

2. The swirl shaft type energy dissipation structure according to claim 1, characterized in that: The cross-sections of the upper flat section (1) and the lower flat section (3) are one of an open channel section, a city gate section, a circle, and a horseshoe section.

3. The swirl shaft type energy dissipation structure according to claim 1, characterized in that: The swirl shaft (2) is arranged at a position close to the flow channel inlet (11).

4. The swirl shaft type energy dissipation structure according to claim 1, characterized in that: The cyclone shaft (2) is circular.

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