Aeration system for deep draft hole working gate

Abstract

This utility model discloses an aeration system, particularly an aeration system for a deep-type spillway gate, belonging to the field of hydraulic engineering structure design and manufacturing technology. It provides an aeration system for a deep-type spillway gate that effectively improves the flow pattern of downstream water, thereby effectively reducing cavitation damage. The aeration system includes a high concrete dam and deep-type spillways and an arc-shaped working gate structure arranged on it. An outlet maintenance platform is provided at the outlet end of the arc-shaped working gate structure. It also includes a erosion-reducing drop and an outlet air supply structure, arranged on the high concrete dam in accordance with the location of the outlet maintenance platform. During flood discharge, the main cavitation cavity formed by the gate pier, the outlet maintenance platform, the lower edge of the outlet water jet, and the working sill of the arc-shaped working gate structure expands with the cooperation of the erosion-reducing drop. The cavitation damage within the main cavitation cavity is reduced or partially eliminated by the air supplied by the outlet air supply structure.

Description

Technical Field

[0001] This utility model relates to an aeration system, and more particularly to an aeration system for working gates of deep spillways, belonging to the field of design and manufacturing technology of water conservancy and hydropower engineering structures. Background Technology

[0002] 1. Explanation of technical terms 1) Cavitation Cavitation refers to the phenomenon where, when the pressure in a water body decreases to a certain critical value, the tiny air bubbles or gas nuclei that were originally present in the water rapidly expand, forming bubbles containing water vapor and other gases in the water. In some cases, massive vaporization may occur, creating a phenomenon similar to boiling. Cavitation is a result of hydrodynamic processes; that is, it is a localized flow phenomenon caused by increased flow velocity and decreased pressure. It includes the initial formation, development, and disappearance of cavitation bubbles, and is a dynamic flow phenomenon.

[0003] 2) Cavitation Cavitation is random and can occur in water or at the edges of solid surfaces. When cavitation occurs near a solid surface, the large instantaneous pressure generated when the cavitation bubbles collapse repeatedly acts on the solid surface, causing damage. This phenomenon is called cavitation erosion. Cavitation erosion is the result of the combined effect of the destructive power of cavitation and the cavitation resistance of the edge material, and it is generally a type of fatigue failure.

[0004] 3) Gas-infused corrosion reduction When cavitation damage to hydraulic structures is unavoidable due to factors such as water flow conditions and flow patterns, the most effective method is to install an aeration trough in front of the cavitation-prone area to form an aeration cavity. The negative pressure in the aeration cavity forces a large amount of gas into the water flow, forming a highly compressible water-air mixture, thereby delaying or preventing cavitation and protecting the downstream flow surface from cavitation damage.

[0005] 4) Deep drainage hole The spillways located in the middle and bottom of a concrete dam are called deep spillways, also known as deep holes. Deep spillways are the main drainage channels of a concrete dam, characterized by large opening sizes, high operating head and outflow velocity, and significant risks of cavitation and erosion. Their operational status is crucial to the safe operation of the dam. Deep spillways in concrete dams are mostly of the long pressurized type, consisting of an inlet section, a shaft section, and an outlet section. A planar emergency maintenance gate is installed at the inlet, and an arc-shaped working gate is installed at the outlet.

[0006] 5) Sudden expansion and sudden drop in the gate slot The arc-shaped working gate at the outlet of the deep spillway of high concrete dams mostly adopts the pressurized water seal or the eccentric hinge compression water seal type. Both of these water seal types require the use of a gate slot structure with sudden expansion on both sides and sudden drop at the bottom, i.e., sudden expansion and sudden drop gate slot. The side cavity is formed by the sudden expansion on both sides and the bottom cavity is formed by the sudden drop at the bottom, which is connected to the atmosphere to achieve the function of aeration and erosion reduction on the side and bottom of the gate slot.

[0007] 2. Deep spillway structure of high concrete dam body Deep spillway openings in high concrete dams typically employ a long pressurized spillway design, consisting of an inlet section, a spillway body section, and an outlet section. 1) The inlet section of the deep spillway of the high concrete dam body consists of the inlet gate pier, the inlet corbel, the emergency gate slot, the emergency gate vent, and the bottom sill of the emergency gate slot; 2) The outlet section of the deep spillway of the high concrete dam body consists of the outlet gate pier, the working arc gate support beam, the outlet corbel, the working arc gate slot, the working arc gate bottom sill, and the working arc gate opening and closing machine room; 3) An exit maintenance platform is arranged downstream of the working arc gate sill for the maintenance of the arc gate during operation. The upper surface of the downstream exit bracket is of the inclined type and is connected to the exit maintenance platform upstream.

[0008] 3. Problems with the working arc gate slot at the outlet of the deep spillway in the high concrete dam body High concrete dams with deep spillways have high operating heads and outflow velocities, making them prone to cavitation erosion, which affects the operational safety of the outlet gate structure. Therefore, aeration erosion reduction measures are necessary. However: 1) The working gate sill adopts a sudden drop type, mainly relying on air mixing through the space between the outlet maintenance platform, the downstream upper surface of the outlet bracket, and the lower edge of the outlet water tongue. When the deep-type drain outlet is at a downward angle, the space between the outlet maintenance platform, the downstream upper surface of the outlet bracket, and the lower edge of the outlet water tongue is small, which cannot provide sufficient erosion reduction ventilation for the working gate sill, and may cause cavitation erosion damage to the working gate sill. 2) The working arc gate sidewall adopts a sudden expansion type, mainly through the cavity formed between the working arc gate slot, the inner wall of the outlet gate pier, and the outlet water tongue, to reduce erosion by top air entrainment. When there are many unstable water fins formed by the outlet water tongue, the water fins often splash to the top of the cavity formed between the working arc gate slot, the inner wall of the outlet gate pier, and the outlet water tongue, blocking the cavity and causing insufficient air entrainment, which leads to cavitation damage to the working arc gate slot. Utility Model Content

[0009] The technical problem to be solved by this utility model is to provide an aeration system for working gates of deep drainage holes that can effectively improve the flow pattern of downstream water and thus effectively reduce the degree of cavitation damage.

[0010] The technical solution adopted to solve the above-mentioned technical problems is: an aeration system for a deep spillway gate, comprising a high concrete dam, a deep spillway on the high concrete dam, an arc-shaped working gate chamber structure on the high concrete dam downstream of the deep spillway, and an outlet maintenance platform at the outlet end of the arc-shaped working gate chamber structure. The aeration system also includes a corrosion-reducing drop and an outlet air supply structure, which are arranged on the high concrete dam in a manner appropriate to the location of the outlet maintenance platform. During flood discharge, the main cavitation cavity formed by the gate pier, the outlet maintenance platform, the lower edge of the outlet water tongue, and the working sill of the arc-shaped working gate chamber structure expands with the cooperation of the corrosion-reducing drop, and the cavitation damage in the main cavitation cavity is reduced or partially eliminated by the air supplied by the outlet air supply structure.

[0011] Furthermore, the corrosion-reducing drop is a vertically bent expansion cavity arranged at the end of the outlet maintenance platform. The spatial distance between the vertical surface at the end of the outlet maintenance platform and the lower edge of the outlet water tongue is increased by at least 10 times through the vertically bent expansion cavity. The downstream upper surface of the outlet bracket is formed by the bent surface of the vertically bent expansion cavity obliquely to the downstream side.

[0012] The preferred embodiment of the above scheme is that the outlet air supply structure includes at least a gate pier air supply pipe. The outlet of the gate pier air supply pipe is connected to the main cavitation cavity from the gate pier above the outlet maintenance platform, and the inlet of the gate pier air supply pipe is connected to the air outside the downstream water body from the gate pier above the outlet water tongue.

[0013] Furthermore, the arc-shaped working gate structure also includes an arc-shaped gate slot and an arc-shaped gate leaf. The mutually adapted arc-shaped gate slot and working sill are arranged on the high concrete dam downstream of the deep spillway, in accordance with the location of the outlet maintenance platform. The arc-shaped gate leaf cuts off the deep spillway in cooperation with the arc-shaped gate slot and the working sill.

[0014] The preferred embodiment of the above scheme is that the outlet air supply structure also includes a bottom sill air supply mechanism. The outlet maintenance platform is arranged on a high concrete dam below the working bottom sill. The outlet end of the bottom sill air supply mechanism is connected to the main cavitation cavity from the wall surface where the outlet maintenance platform is connected to the working bottom sill. The inlet end of the bottom sill air supply mechanism is connected to the air outside the downstream water body from the gate pier above the outlet water tongue.

[0015] Furthermore, the bottom sill air supply mechanism includes a bottom sill air supply main pipe and bottom sill air supply branch pipes. The bottom sill air supply main pipe is arranged in the working bottom sill along the width direction of the deep drainage hole. The air inlet end of each bottom sill air supply branch pipe arranged sequentially in the working bottom sill along the width direction of the deep drainage hole is connected to the bottom sill air supply main pipe at the corresponding position. The air outlet end of each bottom sill air supply branch pipe is independently connected to the main cavitation cavity from the wall surface connected to the working bottom sill by the outlet maintenance platform. The air inlet of the bottom sill air supply main pipe is connected to the air outside the downstream water body from the gate pier above the outlet water tongue.

[0016] The preferred embodiment of the above scheme is that the outlet air supply structure also includes a side wall air supply mechanism. The arc-shaped gate slot end face, the outlet water tongue side face, and the corresponding side face of the gate pier form a side cavitation cavity. The cavitation damage in the side cavitation cavity is reduced or partially eliminated by the air supplied by the side wall air supply mechanism.

[0017] Furthermore, the sidewall air supply mechanism includes a main sidewall air supply pipe and sidewall air supply branch pipes. The main sidewall air supply pipe is arranged in the arc-shaped gate slot along the arc direction. The air outlet of each sidewall air supply branch pipe arranged sequentially in the arc-shaped gate slot along the arc direction is connected to the side cavitation cavity from the end face of the arc-shaped gate slot. The air inlet of each sidewall air supply branch pipe is connected to the corresponding sidewall air supply main pipe. The air inlet of the main sidewall air supply pipe is connected to the air outside the downstream water body from the gate pier above the outlet water tongue.

[0018] The preferred embodiment of the above scheme is that the air inlet of the bottom sill air supply pipe is connected to the side wall air supply pipe from the gate pier position.

[0019] Furthermore, the arc-shaped gate leaf includes the gate leaf body and the support legs. A supporting beam is also provided between two adjacent gate piers. The gate leaf body is arranged on the outlet end of the deep-type drainage hole with the support legs and the support beam.

[0020] The beneficial effects of this utility model are as follows: The technical solution provided in this application is based on the existing high concrete dam, and combines it with the structural features of a deep spillway on the high concrete dam, an arc-shaped working gate chamber structure on the high concrete dam downstream of the deep spillway, and an outlet maintenance platform at the outlet end of the arc-shaped working gate chamber structure. By adding a erosion-reducing drop and an outlet air supply structure, the aeration system of this application is formed, and the erosion-reducing drop and the outlet air supply structure are arranged on the high concrete dam in a manner appropriate to the position of the outlet maintenance platform. Then, during the flood discharge process, the main cavitation cavity formed by the gate pier, the outlet maintenance platform, the lower edge of the outlet water tongue, and the working sill of the arc-shaped working gate chamber structure expands with the cooperation of the erosion-reducing drop. The cavitation damage in the main cavitation cavity is reduced or partially eliminated by the air supplied by the outlet air supply structure. In this way, because the cavity of the main cavitation cavity is expanded to a limited extent, and the corresponding gas is supplied to it through the outlet air supply structure, the flow pattern of the downstream water flow is effectively improved, thereby effectively reducing cavitation damage. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the aeration system of the present invention for a deep-type drainage hole working gate; Figure 2 for Figure 1 AA sectional view.

[0022] The following are marked in the diagram: 1. High concrete dam; 2. Deep spillway; 3. Outlet maintenance platform; 4. Gate pier; 5. Lower edge of outlet water tongue; 6. Working sill; 7. Vertical bending expansion cavity; 8. Vertical surface; 9. Downstream upper surface of outlet corbel; 10. Gate pier air supply pipe; 11. Arc-shaped gate slot; 12. Main air supply pipe for sill; 13. Main air supply pipe for sill; 14. Main air supply pipe for side wall; 15. Support beam; 16. Detailed Implementation

[0023] like Figure 1 , Figure 2This invention provides an aeration system for working gates of deep spillways that effectively improves the flow pattern of downstream water and thus reduces cavitation damage. The aeration system includes a high concrete dam 1, a deep spillway 2 on the high concrete dam 1, an arc-shaped working gate chamber structure on the high concrete dam 1 downstream of the deep spillway, and an outlet maintenance platform 3 at the outlet end of the arc-shaped working gate chamber structure. The aeration system also includes a erosion-reducing sill and an outlet air supply structure, which are arranged on the high concrete dam 1 in a manner appropriate to the position of the outlet maintenance platform 3. During flood discharge, the main cavitation cavity formed by the gate pier 4, the outlet maintenance platform 3, the lower edge of the outlet water tongue 5, and the working sill 6 of the arc-shaped working gate chamber structure expands with the assistance of the erosion-reducing sill. The cavitation damage within the main cavitation cavity is reduced or partially eliminated by the air supplied by the outlet air supply structure. The technical solution provided in this application is based on existing high concrete dams, and combines this with the structural features of deep spillways on the high concrete dam, an arc-shaped working gate chamber structure on the high concrete dam downstream of the deep spillways, and an outlet maintenance platform at the outlet end of the arc-shaped working gate chamber structure. By adding erosion-reducing sills and an outlet air supply structure, the aeration system of this application is constructed, and the erosion-reducing sills and the outlet air supply structure are arranged on the high concrete dam in a manner appropriate to the location of the outlet maintenance platform. Then, during flood discharge, the main cavitation cavity formed by the gate piers, the outlet maintenance platform, the lower edge of the outlet water jet, and the working sill of the arc-shaped working gate chamber structure expands with the cooperation of the erosion-reducing sills. The cavitation damage within the main cavitation cavity is reduced or partially eliminated by the air supplied by the outlet air supply structure. Thus, because the cavity of the main cavitation cavity is expanded to a limited extent, and corresponding gas is introduced into it through the outlet air supply structure, the flow pattern of the downstream water is effectively improved, achieving a significant reduction in cavitation damage. Furthermore, considering the structural characteristics of existing high concrete dams, this application sets the erosion-reducing drop as a vertically bent expansion cavity 7 located at the end of the outlet maintenance platform. This increases the spatial distance between the vertical surface 8 at the end of the outlet maintenance platform and the lower edge 5 of the outlet water jet by at least 10 times through the vertically bent expansion cavity 7. The downstream upper surface 9 of the outlet corbel is formed by the bent surface of the vertically bent expansion cavity angled downstream. This solves the problem in the prior art where the distance between the lower edge 5 of the outlet water jet and the downstream upper surface 9 of the outlet corbel is too small, resulting in severe cavitation damage to the concrete surface caused by the high-speed discharge of water carrying away a large amount of air.

[0024] Accordingly, in order to maximize the air volume within the cavitation cavity while minimizing cavitation damage, the outlet air supply structure of this application includes at least a gate pier air supply pipe 10. The outlet of the gate pier air supply pipe 10 connects to the main cavitation cavity from the gate pier 4 above the outlet maintenance platform 3, and the inlet of the gate pier air supply pipe 10 connects to the air outside the downstream water body from the gate pier 4 above the outlet water tongue. Furthermore, considering the characteristics of the arc-shaped working gate chamber structure, which also includes an arc-shaped gate slot 11 and an arc-shaped gate leaf, this application arranges the mutually adaptable arc-shaped gate slot 11 and working sill 6 in a manner appropriate to the position of the outlet maintenance platform 3 on the high concrete dam 1 downstream of the deep spillway. The arc-shaped gate leaf, in conjunction with the arc-shaped gate slot 11 and working sill 6, cuts off the deep spillway. Meanwhile, considering the layout characteristics of deep spillway holes on high concrete dams, the outlet air supply structure of this application also includes a bottom sill air supply mechanism and a side wall air supply mechanism. The outlet maintenance platform 3 is arranged on the high concrete dam 1 below the working bottom sill. The air outlet end of the bottom sill air supply mechanism is connected to the main cavitation cavity from the wall surface where the outlet maintenance platform 3 is connected to the working bottom sill 6. The air inlet end of the bottom sill air supply mechanism is connected to the air outside the downstream water body from the gate pier above the outlet water tongue. The arc-shaped gate slot end face, the side of the outlet water tongue, and the corresponding side of the gate pier 4 form a side cavitation cavity. The cavitation damage in the side cavitation cavity is reduced or partially eliminated by the air supplied by the side wall air supply mechanism. More specifically, the bottom sill air supply mechanism of this application includes a bottom sill air supply main pipe 12 and bottom sill air supply branch pipes 13. The bottom sill air supply main pipe 12 is arranged in the working bottom sill 6 along the width direction of the deep drainage hole. The air inlet end of each bottom sill air supply branch pipe 13 arranged sequentially in the working bottom sill 6 along the width direction of the deep drainage hole is connected to the bottom sill air supply main pipe 12 at the corresponding position. The air outlet end of each bottom sill air supply branch pipe 13 is independently connected to the main cavitation cavity from the wall surface of the outlet maintenance platform 3 connected to the working bottom sill 6. The air inlet of the bottom sill air supply main pipe 12 is connected to the air outside the downstream water body from the gate pier above the outlet water tongue. The sidewall air supply mechanism of this application includes a sidewall air supply main pipe 14 and sidewall air supply branch pipes 15. The sidewall air supply main pipe 14 is arranged in the arc-shaped gate slot 11 along the arc direction. The air outlet of each sidewall air supply branch pipe 15 arranged sequentially in the arc-shaped gate slot 11 along the arc direction is connected to the side cavitation cavity from the end face of the arc-shaped gate slot. The air inlet of each sidewall air supply branch pipe 15 is connected to the sidewall air supply main pipe 14 at the corresponding position. The air inlet of the sidewall air supply main pipe 14 is connected to the air outside the downstream water body from the gate pier 4 above the outlet water tongue.

[0025] In light of the actual conditions at the construction site, the air inlet of the bottom sill air supply main pipe 12 of this application is connected to the side wall air supply main pipe 14 from the gate pier position. The arc-shaped gate leaf includes the gate leaf body and the support legs. A support beam 16 is also provided between two adjacent gate piers 4. The gate leaf body is arranged on the outlet end of the deep drainage hole 2 with the support legs and the support beam 16.

[0026] In summary, the technical solution provided in this application also has the following advantages: 1. Multiple air intake sources. Compared with conventional working arc gate slots which only have two air intake sources connected to the free atmosphere—the sudden drop in the bottom sill of the working arc gate and the sudden expansion of the working arc gate slot—the working arc gate slot of this application includes the following air intake sources: 1) The bottom sill of the working arc gate is connected to the free atmosphere; 2) The bottom sill of the working arc gate is connected to the free atmosphere outside the outlet gate pier through the air supply pipe of the gate pier; 3) The working arc gate slot is connected to the free atmosphere at the top through the side wall air supply main pipe; 4) The working arc gate slot is connected to the free atmosphere above the upper edge of the outlet water tongue through the side wall air supply branch pipe.

[0027] 2. High ventilation volume. Compared with conventional working arc gate slots, the ventilation volume of the working arc gate slot in this application will be significantly increased: 1) The downstream maintenance platform of the working arc gate is connected to the downstream upper surface of the outlet bracket through a drop sill. The distance between the outlet maintenance platform and the lower edge of the outlet water tongue is significantly increased, which is beneficial to the aeration and corrosion reduction in this part. 2) A gate pier air supply pipe is installed downstream of the working gate sill, which is connected to the free atmosphere outside the outlet gate pier, providing more ventilation for the working gate sill to reduce corrosion by adding air. 3) The side wall of the working arc gate slot is equipped with a side wall ventilation main pipe that is connected to the free atmosphere at the top, and a side wall ventilation branch pipe that is connected to the free atmosphere at the upper edge of the outlet water tongue, which can provide more ventilation for the air-entraining and erosion reduction of the side wall of the working arc gate slot.

[0028] 3. Excellent air entrainment effect. Compared with conventional working arc gate slots, the air entrainment effect of the working arc gate slot in this application will be significantly improved: 1) For the bottom sill of the working arc gate, the air supply sources include the space between the outlet maintenance platform and the lower edge of the outlet water tongue, the gate pier air supply pipe, and the bottom sill air supply branch pipe (connected to the free atmosphere through the bottom sill air supply main pipe and the side wall air supply main pipe). Even under conditions of poor outlet water tongue flow and insufficient space between the lower edge of the outlet water tongue and the outlet maintenance platform, sufficient air supply can be achieved. 2) For the sidewall of the working arc gate slot, the air supply sources include the working arc gate slot, the inner wall of the outlet gate pier, and the top cavity between the outlet water jet, as well as the sidewall air supply branch pipes (including lower air introduced by the main sidewall air supply pipe, the main bottom sill air supply pipe, and the bottom sill air supply branch pipe, and upper air introduced by the main sidewall air supply pipe and the sidewall air supply branch pipe). Even when there are many unstable water jets formed by the outlet water jet, and the water jets block the cavity formed between the working arc gate slot, the inner wall of the outlet gate pier, and the outlet water jet, sufficient air supply to the sidewall of the working arc gate slot can still be achieved.

[0029] The aforementioned aeration structure for the working arc gate slot of the deep spillway in the high concrete dam body enables efficient aeration of the bottom sill and sidewalls of the working arc gate, ensuring that the working arc gate slot structure is protected from cavitation damage.

[0030] The technical solution of this application will be further described below through specific embodiments: The technical problem to be solved by this application is to provide an air-entraining structure for the working arc gate slot of a deep spillway in a high concrete dam that can achieve efficient air entrainment in the bottom sill and sidewall of the working arc gate slot, and ensure that the working arc gate structure is protected from cavitation damage.

[0031] The technical solution adopted in this application to solve the technical problem is as follows: 1. The deep spillway of a high concrete dam consists of an inlet section, a spillway body section, and an outlet section: 2. The inlet section of the deep spillway of the high concrete dam body consists of the inlet gate pier, the inlet corbel, the emergency gate slot, the emergency gate vent, and the bottom sill of the emergency gate slot; 3. The outlet section of the deep spillway of the high concrete dam body consists of the outlet gate pier, the working arc gate support beam, the outlet corbel, the working arc gate slot, the working arc gate bottom sill, and the working arc gate opening and closing machine room; 4. An exit maintenance platform is arranged downstream of the working arc gate sill for the maintenance of the arc gate during operation. A drop sill is set downstream of the exit maintenance platform to connect with the upper surface of the downstream of the exit bracket. 5. The working arc gate slot aeration facility consists of a gate pier aeration pipe, a bottom sill aeration structure, and a side wall aeration structure. Among them: 1) The air supply pipes of the gate piers are arranged on both sides of the outlet gate piers of the deep drainage hole, with the inner side connected to the downstream side of the bottom sill of the working arc gate and the outer side connected to the outside of the outlet gate pier to the free atmosphere; 2) The bottom sill air supply structure consists of a bottom sill air supply main pipe and bottom sill air supply branch pipes. The bottom sill air supply main pipe is located in the concrete under the bottom sill of the working arc gate, and its downstream side is connected to the free atmosphere through the bottom sill air supply branch pipes. Both ends are connected to the side wall air supply main pipe. 3) The sidewall air supply structure consists of a main sidewall air supply pipe and a sidewall air supply branch pipe. The main sidewall air supply pipe is arranged in the working arc gate slot on both sides of the deep drainage hole outlet. The lower part is connected to the bottom sill air supply pipe, and the upper part is connected to the free atmosphere at the top of the working arc gate slot. The downstream side is connected to the working arc gate slot, the inner wall of the outlet gate pier and the cavity formed between the outlet water tongue through the sidewall air supply branch pipe.

Claims

1. An aeration system for a deep spillway working gate, comprising a high concrete dam (1), a deep spillway (2) provided on the high concrete dam (1), an arc-shaped working gate structure provided on the high concrete dam (1) downstream of the deep spillway, and an outlet maintenance platform (3) provided at the outlet end of the arc-shaped working gate structure, characterized in that: The aeration system also includes a erosion reduction sill and an outlet air supply structure. The erosion reduction sill and the outlet air supply structure are arranged on the high concrete dam (1) in accordance with the location of the outlet maintenance platform (3). During the flood discharge, the main cavitation cavity formed by the gate pier (4), the outlet maintenance platform (3), the lower edge of the outlet water tongue (5), and the working sill (6) of the arc-shaped working gate chamber structure expands with the cooperation of the erosion reduction sill. The cavitation damage in the main cavitation cavity is reduced or partially eliminated by the air supplied by the outlet air supply structure.

2. An aeration system for a deep drop shaft working gate according to claim 1, characterized in that: The corrosion reduction drop is a vertical bending expansion cavity (7) arranged at the end of the outlet maintenance platform. The spatial distance between the vertical surface (8) at the end of the outlet maintenance platform and the lower edge (5) of the outlet water tongue is increased by at least 10 times through the vertical bending expansion cavity (7). The downstream upper surface (9) of the outlet bracket is formed by the bending surface of the vertical bending expansion cavity inclined to the downstream side.

3. An aeration system for a deep draft hole working gate according to claim 1 or 2, characterized in that: The outlet air supply structure includes at least a gate pier air supply pipe (10). The outlet of the gate pier air supply pipe (10) is connected to the main cavitation cavity from the gate pier (4) above the outlet maintenance platform (3). The inlet of the gate pier air supply pipe (10) is connected to the air outside the downstream water body from the gate pier (4) above the outlet water tongue.

4. An aeration system for a deep drop shaft working gate according to claim 3, characterized in that: The arc-shaped working gate structure also includes an arc-shaped gate slot (11) and an arc-shaped gate leaf. The mutually adapted arc-shaped gate slot (11) and working sill (6) are arranged on the high concrete dam (1) on the downstream side of the deep spillway in accordance with the position of the outlet maintenance platform (3). The arc-shaped gate leaf cuts off the deep spillway in cooperation with the arc-shaped gate slot (11) and working sill (6).

5. An aeration system for a deep drop shaft working gate according to claim 4, characterized in that: The outlet air supply structure also includes a bottom sill air supply mechanism. The outlet maintenance platform (3) is arranged on the high concrete dam (1) below the working bottom sill. The outlet end of the bottom sill air supply mechanism is connected to the main cavitation cavity from the wall surface where the outlet maintenance platform (3) is connected to the working bottom sill (6). The inlet end of the bottom sill air supply mechanism is connected to the air outside the downstream water body from the gate pier (4) above the outlet water tongue.

6. An aeration system for a deep drop shaft working gate according to claim 5, characterized in that: The bottom sill air supply mechanism includes a bottom sill air supply main pipe (12) and bottom sill air supply branch pipes (13). The bottom sill air supply main pipe (12) is arranged in the working bottom sill (6) along the width direction of the deep drainage hole. The air inlet of each bottom sill air supply branch pipe (13) arranged sequentially in the working bottom sill (6) along the width direction of the deep drainage hole is connected to the bottom sill air supply main pipe (12) at the corresponding position. The air outlet of each bottom sill air supply branch pipe (13) is independently connected to the main cavitation cavity from the wall surface connected to the working bottom sill (6) of the outlet maintenance platform (3). The air inlet of the bottom sill air supply main pipe (12) is connected to the air outside the downstream water body from the gate pier (4) above the outlet water tongue.

7. An aeration system for a deep drop shaft working gate according to claim 6, characterized in that: The outlet air supply structure also includes a side wall air supply mechanism. The arc-shaped gate slot end face, the outlet water tongue side face and the corresponding side of the gate pier (4) form a side cavitation cavity. The cavitation damage in the side cavitation cavity is reduced or partially eliminated by the air supplied by the side wall air supply mechanism.

8. An aeration system for a deep drop shaft working gate according to claim 7, characterized in that: The sidewall air supply mechanism includes a sidewall air supply main pipe (14) and a sidewall air supply branch pipe (15). The sidewall air supply main pipe (14) is arranged in the arc direction of the arc gate slot (11). The air outlet of each sidewall air supply branch pipe (15) arranged in the arc direction is connected to the side cavitation cavity from the end face of the arc gate slot. The air inlet of each sidewall air supply branch pipe (15) is connected to the sidewall air supply main pipe (14) at the corresponding position. The air inlet of the sidewall air supply main pipe (14) is connected to the air outside the downstream water body from the gate pier (4) above the outlet water tongue.

9. An aeration system for a deep drop shaft working gate according to claim 8, characterized in that: The air inlet of the bottom sill air supply pipe (12) is connected to the side wall air supply pipe (14) from the position of the gate pier (4).

10. The aeration system for a deep drop shaft working gate according to claim 4, characterized in that: The arc-shaped gate leaf includes the gate leaf body and the support legs. A support beam (16) is also provided between two adjacent gate piers (4). The gate leaf body is arranged on the outlet end of the deep drainage hole (2) with the support legs and the support beam (16).

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