CN111877277A - A kind of arc-shaped gate air-entraining structure with sudden expansion and sudden drop in the low-pressure area of side wall impact rebound - Google Patents

Abstract

The invention discloses an arc-shaped gate air-entraining structure with sudden expansion and sudden drop in the low-pressure area of side wall impact rebound. Sudden drop aeration structure; the arc gate is placed horizontally on the side wall, the bottom plate is located at the bottom end of the side wall, the ventilation hole is located downstream of the arc gate and connected to the cavity area at the top of the water flow after the downstream flood discharge, a sudden expansion and sudden drop water stop structure Located upstream of the arc gate, the secondary sudden expansion and sudden drop aeration structure is located at the junction of the water flow impact area downstream of the vent hole and the low pressure area. In the air-entrained structure of the arc-shaped gate provided by the invention, the side wall is suddenly expanded twice in the low-pressure area to form a longer side-aerated cavity, so that the water flow in the original low-pressure area no longer sticks to the side wall, and the cavitation is destroyed by cavitation. The starting point is located in the low pressure area. When the water flow no longer sticks to the side wall, even if the water flow is cavitated, the side wall will not be damaged by cavitation; the gate can operate safely under various opening degrees, and the operation of the gate is no longer affected. limit.

Description

A kind of arc-shaped gate air-entraining structure with sudden expansion and sudden drop in the low-pressure area of side wall impact rebound

technical field

The invention relates to the field of water conservancy and hydropower, in particular to an arc-shaped gate aeration structure with a side wall impacting and rebounding a low-pressure area with sudden expansion and sudden drop.

Background technique

For the traditional high head arc gate, due to the need for water stop, a sudden expansion and sudden drop structure must be set along the edge of the arc gate. part, so as to achieve better water stop.

Due to the high speed of water flow during flood discharge with high head, it is easy to cause cavitation erosion damage, and good aeration can well avoid cavitation erosion damage and protect the safety of the overflow wall. The existing technology is to use the sudden expansion and sudden drop structure of the arc gate to increase the width of the sudden expansion and the height of the sudden drop, and combine the water-stop sudden expansion and sudden drop structure with the aerated sudden expansion and sudden drop structure. To meet the requirements of water stop and aeration, the aeration structure of the now widely used sudden expansion and sudden drop arc gate is shown in Figures 3 and 4.

However, in the actual project operation process, after using the structures shown in Figures 3 and 4, there are still a lot of cavitation damage. Taking a project as an example, since it was put into operation, several erosion damages have occurred in the flood discharge cavity. As shown in Figures 5 and 6, the position where cavitation damage began to occur on the inner side wall of the flood discharge cavity is far from the bottom plate of the arc gate exit. The horizontal distance of the position is about 4m, and then the damage gradually develops to the bottom plate, and the damage is more serious. When the flood discharge cavity gate is partially opened, the length of the side cavity is very small, the aeration effect is poor, and a large area of clear water appears in the water flow; when the gate is fully opened, the length of the side cavity increases slightly, but the aeration effect is The effect is still unsatisfactory, and the clear water area in the water flow is still very large, as shown in Figure 7-10. The large unaerated clear water area makes the sidewall prone to cavitation damage.

The Chinese patent with the application number of CN201911243333.6 discloses a short platform for preventing the water flow obliquely from the outlet of the arc gate with pressure flood discharge. The oblique water flow falls on the platform to avoid the long-term impact of the water flow on the bottom plate due to the oblique shot at a large angle, resulting in the scour damage of the bottom plate; and because the oblique water flow only travels a short distance when the arc gate is opened, it falls on the platform, which will cause damage to the platform. The impact force is far less than the direct impact on the bottom plate. However, it cannot solve the problem of cavitation damage in the clear water area of the side wall. After the water flow hits the side wall, the water flow in the rebound low pressure area cannot be effectively aerated, and it is still clear water, so the side wall will still be damaged by cavitation erosion.

SUMMARY OF THE INVENTION

In order to solve the above problems, the purpose of the present invention is to provide a kind of arc-shaped gate aeration structure with sudden expansion and sudden drop in the low-pressure area of side wall impact rebound, so as to solve the poor aeration effect of the existing sudden expansion and sudden drop of the arc gate, and the side wall The clean water area is prone to cavitation damage.

In order to achieve the above purpose, the technical scheme adopted in the present invention:

An arc-shaped gate aeration structure with sudden expansion and sudden drop in the low-pressure area of side wall impact rebound, comprising an arc-shaped gate, a side wall, a bottom plate, a ventilation hole, a water-stop structure with a sudden expansion and a sudden drop, and aeration aeration with a second sudden expansion and sudden drop structure; the arc-shaped gate is placed horizontally on the side wall, the bottom plate is located at the bottom end of the side wall, the ventilation hole is located downstream of the arc-shaped gate and communicates with the cavity area at the top of the water flow after the downstream flood discharge, the primary protruding The water-stop structure is located upstream of the arc-shaped gate, and the secondary aeration structure is located at the junction of the water flow impact area downstream of the vent hole and the low-pressure area.

According to the experimental research results, the disadvantage of the traditional arc gate structure with sudden expansion and sudden fall is the insufficient air aeration in the side cavity. When the water flow through the sudden expansion and sudden fall of the arc gate spreads laterally and impacts the side wall, an impact zone is formed. The side wall in the impact zone is under high pressure, so cavitation damage is not easy to occur. However, the laterally diffused water flow impacts the side wall. There is a tendency to bounce behind the wall, and while this bounce does not dislodge the flow from the side walls, it does create an area of low pressure downstream of the impact area, as shown in Figure 11. Due to the short side cavity and insufficient air entrainment, the water flow in the impact area of the side wall and the subsequent low pressure area is often clear water, which makes the side wall prone to cavitation damage. In the present application, a secondary sudden expansion and sudden drop aeration structure is provided at the junction of the water flow impact area downstream of the vent hole and the low pressure area, which solves this defect.

Further, the secondary sudden expansion and sudden drop aeration structure includes aerated sudden expansion and aerated aerated drop; the side wall includes left and right side walls, and the downstream sides of the left and right side walls widen inwardly to form the described side wall. The aeration suddenly expands, which solves the problem of insufficient air aeration in the side cavity and easy cavitation damage to the side wall; the water flow creates a drop at the bottom plate and aerates the air, forming the aeration abrupt drop, so as to improve the bottom cavity aeration. Effect.

Further, the aeration sudden expansion is located at 2-3m downstream of the bottom of the arc gate, and the sides of the left and right side walls are each widened inward by 0.5-1m. This position is the first sudden expansion of the water flow impact area and The junction of the low pressure area.

Further, the primary sudden expansion and sudden drop water stop structure includes a water stop sudden expansion at the upstream of the arc gate and a water stop drop sill at the bottom end.

Further, the aerated drop includes a platform, a support structure and a ventilation channel; the platform is connected to the water-stop sill, and is erected on the support structure to form a drop with the bottom plate; the support structure is located on the bottom plate The ventilation channel is located below the platform, the front end of which is connected to the ventilation hole, and the rear end is connected to the bottom cavity of the downstream water flow after flood discharge.

The platform is used to change the direction of the downward oblique water flow, and the oblique water flow is shot horizontally from the platform, so as to prevent the water flow from hitting the bottom plate at a large angle due to the oblique shot for a long time, causing the bottom plate to be scoured and damaged. The support structure is used to support the platform and form ventilation channels. The ventilation channel is used to connect the ventilation hole and the bottom cavity, aerate the bottom cavity, and the water flow is injected horizontally from the platform, which greatly increases the length of the bottom cavity and improves the bottom aeration effect; Cavitation damage caused by insufficient air aeration in the water flow; at the same time, the length of the bottom cavity is increased, which can also reduce the backwater of the bottom cavity.

Further, the support structure is a plurality of evenly distributed support columns, and the cavity area between the plurality of support columns forms the ventilation channel. On the one hand, the function of the support column is to support the platform, and on the other hand, the function of the support column is to form a ventilation channel between the support columns.

Further, the support structure is a concrete structure with a plurality of pipes arranged vertically and horizontally inside, and supports the platform, and the ventilation channels are formed inside the pipes to communicate with the ventilation holes and the bottom cavity.

Further, the length of the platform is 2-3m, and the material is concrete. The function of the platform is to adjust the direction of the downwardly sloping water flow to be horizontal when the gate is opened, so it cannot be too short, and the adjustment is not sufficient. After research, 2m can achieve the effect of adjusting the level. The optimal choice for the secondary sudden expansion and sudden collapse of aerated structure is to suddenly expand and collapse at the same time, so the platform should not be too long; if it is too long, the side wall has entered the rebound low pressure area, and cavitation erosion damage has already occurred in this area. , so the longest is not more than 3m. Since the oblique jet of water falls on the platform after only a short distance when the arc gate is opened, the impact force on the platform is far less than the direct impact on the bottom plate, so the platform will not be scoured and damaged.

Further, the water-stop sudden expansion is located on the left and right side walls upstream of the arc-shaped gate. The shape is extended inward of the side wall and is connected with the side wall to form the water-stop protruding expansion. The sudden expansion of the water stop is that when the water blocking head of the gate is large, the eccentric twisted arc gate can be used to increase the water stop capacity of the gate, and after the water flows out of the gate, an air-filled cavity can be formed on the side, and the water flow can be laterally controlled. Aerated.

Further, the water-stop sill is placed horizontally at the bottom end of the two side walls and is connected with the bottom end of the arc-shaped gate. Preferably, the side of the water-stop sill is adapted to the bottom of the arc-shaped gate. Curved surface for better water stop when the curved gate is closed.

Beneficial effects of the present invention:

1. The side wall suddenly expands in the low pressure area to form a longer side aerated cavity, so that the water flow in the original low pressure area no longer sticks to the side wall, and the starting point of cavitation damage is located in the low pressure area. When it is attached to the side wall, even if the water flow is cavitated, the side wall in this area will not be damaged by cavitation because it does not touch the side wall.

2. The low pressure area can suck the surrounding air, so it can be better aerated, so that the air aeration on the side of the water flow is more sufficient. After the fully aerated water flow, it passes through a long cavity section, crosses the low pressure area, and contacts again. After the downstream side wall, the side wall will no longer be damaged by cavitation due to a large amount of aeration on the side of the water flow.

3. The starting point of the sudden expansion of the original technology is an arc, and the starting points are all upstream of the starting point of the bottom cavity. In the prior art, the length of the side cavity is generally not more than 5-6m, and the water flow at the end of the side cavity can easily enter the bottom cavity. In the present invention, the starting position of the aerated side cavity and the aerated bottom cavity is the same, and there is a platform with a length of about 2-3m after the water stop at the bottom of the arc gate. , after hitting the side wall, the water that is slanted downward falls on this platform, and then flows out after being adjusted to the level, and will not fall into the bottom cavity and affect the aeration effect of the bottom cavity.

4. The original technology has strict restrictions on the operation of the gate. When the gate opening is between 0.2 and 0.8, there is an obvious clear water area on the side wall, which is prone to cavitation damage, resulting in more serious erosion damage. . The gate of the present invention can operate safely under various opening degrees, and there is only a clear water area on the side wall between the sudden expansion of the water stop and the sudden expansion of aeration, but this area is impacted by the water flow, and the side wall The pressure of the water flow is large, the cavitation number of the water flow is large, and the cavitation erosion damage will not occur. After the sudden expansion of the aeration point, the clear water area is separated from the wall surface to form an aerated cavity, and a large amount of air is already aerated when it contacts the side wall again. Therefore, the side walls are protected by aeration, and cavitation erosion damage will not occur, so after the present invention is adopted, the operation of the gate is no longer restricted.

Description of drawings

Fig. 1 is the side view of the present invention;

Fig. 2 is the top view of the present invention;

Fig. 3 is the side view of the aeration structure of the sudden expansion and sudden drop arc gate adopted in the prior art;

Fig. 4 is the top view of the aeration structure of the sudden expansion and sudden drop arc gate adopted in the prior art;

Figure 5-6 is a photo of the cavitation damage of the rear side wall of the arc gate in the venting hole of a project;

Figure 7-10 is a photo of the side cavity shape of the traditional sudden expansion and sudden drop arc gate structure and model test of a project;

Figure 11 is a schematic diagram of the water flow state of the traditional sudden expansion and sudden fall arc gate structure;

Fig. 12 is that a certain model adopts the test result photo of the present invention;

Figure 13 is a photo of a model using the original technology;

Fig. 14 is the schematic diagram of the water flow when the gate is opened after adopting the present invention;

In the figure: 1. Arc-shaped gate; 2. Side wall; 3. Bottom plate; 4. Ventilation hole; 5. Sudden expansion of air aeration; 6. Sudden expansion of water stop; Supporting structure; 10. Ventilation channel; 11. Bottom cavity.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention is further described below with reference to the accompanying drawings. In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inside", " The orientation or positional relationship indicated by "outside" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, so as to The specific orientation configuration and operation are therefore not to be construed as limitations of the present invention.

In the description of the present invention, it should be noted that, unless otherwise expressly specified and limited, the terms "installation", "provided with", "sleeve/connection", "connection", etc., should be understood in a broad sense, such as " Connection", which can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be an internal connection between two components. of connectivity. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

Example 1

An arc-shaped gate aeration structure with sudden expansion and sudden drop in the low-pressure area of side wall impact rebound, as shown in Figures 1 and 2, includes arc-shaped gate 1, side wall 2, bottom plate 3, ventilation hole 4, a sudden expansion and sudden drop Water-stop structure and secondary sudden expansion and sudden drop aerated structure. The arc-shaped gate 1 is placed horizontally on the side wall 2, the bottom plate 3 is located at the bottom end of the side wall 2, and the ventilation hole 4 is located downstream of the arc-shaped gate 1 and communicates with the cavity area at the top of the water flow after the downstream flood discharge. Located upstream of the arc gate 1, the secondary sudden expansion and sudden drop aeration structure is located at the junction of the water flow impact area downstream of the vent hole 4 and the low pressure area.

The primary sudden expansion and sudden drop water stop structure includes a water stop sudden expansion 6 upstream of the arc gate 1 and a water stop sill 7 at the bottom end. Specifically, the water-stop sudden expansion 6 is located on the left and right side walls 2 upstream of the arc-shaped gate 1 , and the downstream end surface of the water-stop sudden expansion 6 is an arc-shaped surface adapted to the arc-shaped gate 1 , and the arc-shaped face extends into the side wall 2 And it is connected with the side wall 2 to form a water stop and sudden expansion 6 . The water stop sill 7 is placed horizontally at the bottom end of the two side walls 2 and connected with the bottom end of the arc gate 1 , and the side surface of the water stop sill 7 is an arc surface adapted to the bottom of the arc gate 1 . After the water flows out of the gate, an air-filled cavity is formed on the side, and the water flow is aerated on the side, and the water-stop requirements are met at the same time.

The secondary sudden expansion and sudden drop aeration structure includes aerated sudden expansion 5 and aerated sudden drop; side wall 2 includes left and right side walls, and the downstream sides of left and right side walls 2 widen inward to form aerated sudden expansion 5; water flows on the bottom plate 3 places produce a drop and aeration, resulting in a sudden drop in aeration. Specifically, the aeration sudden expansion 5 is located 2-3m downstream of the bottom of the arc-shaped gate 1, and the sides of the left and right side walls 2 are each expanded by 0.5-1m inward. In this example, according to the actual damage situation of a certain project, the position where cavitation damage occurs on the side wall is about 4m away from the gate bottom plate, so the aerated expansion 5 is set at 3m away from the gate bottom plate, and the sides of the left and right side walls 2 are widened inwards. 0.7m.

Air-entrained sudden expansion 5 is a secondary sudden-expansion structure. The side wall is suddenly expanded in the low-pressure area to form a longer side-aerated cavity, so that the water flow in the original low-pressure area no longer sticks to the side wall, and the low-pressure area can be further expanded. Good aeration makes the air aeration more sufficient. After the fully aerated water flow contacts the side wall again, the side wall will also be aerated due to the large amount of water flow, and there will be no cavitation damage. At the same time, the gate can be operated safely under various opening degrees, and the side walls are protected by aeration, and cavitation erosion will not occur. Therefore, the operation of the gate is no longer restricted after the invention is adopted.

Air-entrained sudden drop includes platform 8, support structure 9 and ventilation channel 10; platform 8 is connected to water-stop sill 7, and is erected on support structure 9 to form a drop with bottom plate 3; support structure 9 is located on bottom plate 3; ventilation channel 10 is located at Below the platform 8, its front end communicates with the ventilation hole 4, and its rear end communicates with the bottom cavity of the downstream water flow after flood discharge.

In this embodiment, the support structure 9 is a plurality of evenly distributed support columns, and a ventilation channel 10 is formed in the cavity area between the plurality of support columns. Meanwhile, the support structure 9 may also be other structures, for example, the support structure 9 is a concrete structure with a plurality of pipes arranged vertically and horizontally inside, and a ventilation channel 10 is formed inside the pipes.

When the arc gate 1 is opened, the water flow that shoots downward obliquely falls on the platform 8 after a short distance. The scouring damage caused by the water flow directly hitting the bottom plate 3 is avoided, and the impact force on the platform 8 is far less than the direct impact on the bottom plate 3 .

The air enters the bottom of the platform 8 from the ventilation hole 4. After the bottom of the platform 8 is fully adjusted through the ventilation channel 10, it enters the bottom cavity formed after the jetting water flow is separated from the platform from the bottom of the water jet, which is consistent with the direction of the water flow. The air flow in the bottom cavity is smoother and the ventilation strength is enhanced. At the same time, due to the addition of the platform 8, the water flow is horizontally ejected from the platform 8, thereby increasing the length of the bottom cavity, and enhancing the ventilation volume and aeration effect of the bottom cavity. It also avoids the cavitation damage caused by the short bottom cavity and insufficient water aeration. In addition, the backwater of the bottom cavity is also reduced, and the backwater is prevented from blocking the ventilation hole 4 .

According to the model test results, the newly added side wall aeration and sudden expansion structure makes the water flow through the water-stop sudden expansion and impact the side wall, and before entering the side wall low pressure area, the side wall suddenly expands and aerates again, so that the water flow in the original side wall low pressure area Separated from the wall, this area forms a side wall aerated cavity area, and the water flow is aerated. The newly expanded side aeration effect is very good, the original low-pressure clear water area quickly disappears, and the water flow has been heavily aerated when the wall is attached again. Figures 12 and 13 show the comparison between the original technology and the flow state after adopting the present invention.

In this embodiment, the parameters of the aerated structure are as follows:

The water stop 6 is suddenly expanded by 0.5m, the water stop sill 7 is a curve consistent with the arc opening gate 1, the vertical height is 0.3m, and the water stop sill 7 is followed by a short platform 8 with a length of 3m. At the end of the short platform 8, there is a sudden expansion and sudden drop of aerated air, that is, the bottom plate 3 suddenly drops by 2m, and the side wall 2 suddenly expands by 0.7m at the same position where the bottom plate 3 suddenly drops.

Comparative ratio

The comparison example is to set the sudden expansion and sudden drop only at the arc gate, and the parameters are as follows:

A sudden expansion of 1m at the arc gate, this sudden expansion has two functions of water stop and aeration. For a high vertical drop, because the height of the sudden drop is much larger than the height of the arc-shaped water stop drop, it is customary to call this form a sudden drop. The total drop height here is 2.3m.

The data of embodiment and comparative example are as follows:

The data of the bottom cavity in the embodiment of table 1

Gate opening (m) Reservoir water level (m) Bottom cavity length (m) 2.5 2092.42 15.52 3 2092.04 15.26 fully open 2092.66 12.54

Table 2 compares the data of the bottom cavity

Gate opening (m) Reservoir water level (m) Bottom cavity length (m) 2.5 2092.42 13.74 3 2092.04 11.7 fully open 2092.66 10.86

Table 3 Various data of the side cavity of the embodiment

gate status Gate opening (m) Bottom cavity length (m) open 0.5～3 5.1～9.39 fully open 4.1 7.11～9.18

Table 4 The data of the cavity on the comparative side

gate status Gate opening (m) Bottom cavity length (m) open 0.5～3 1.53～2.2 fully open 4.1 3.72～4.65

It can be seen from Tables 3 and 4 that in the embodiment, when the gate is partially opened, when the gate opening changes from 0.5m to 3m, the length of the side cavity varies from 5.1m to 9.39m; m), the length of the side cavity increases continuously with the increase of the flow rate, and the variation range of the length of the side cavity is between 7.11m and 9.18m. In the comparative example, when the gate is partially open, when the gate opening changes from 0.5m to 3m, the length of the side cavity varies from 1.53m to 2.2m. When the gate is fully opened (4.1m), the length of the side cavity varies with As the flow rate increases, the length of the side cavity varies from 3.72m to 4.65m.

It can be seen from this that in the embodiment, the water flow state is better when the gate is partially opened and when the gate is fully opened, and there are better bottom cavities and side cavities. At each gate opening, the minimum bottom cavity length is greater than 12.5m. The length of the side cavity varies from 5.1m to 9.39m. In contrast, the minimum bottom cavity length is 10.86m, and the side cavity length varies from 1.53m to 4.65m. The minimum bottom cavity length increased by 15.1%, and the maximum bottom cavity length increased by 30.4%; the minimum side cavity length increased by 233.3%, and the maximum side cavity length increased by 101.9%.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. A kind of arc-shaped gate air-entraining structure with sudden expansion and sudden drop in sidewall impact rebound low-pressure zone, is characterized in that, comprises arc-shaped gate (1), side wall (2), bottom plate (3), vent hole (4) , a sudden expansion and sudden drop water-stop structure and a secondary sudden expansion and sudden drop aeration structure; The curved gate (1) is placed horizontally on the side wall (2), the bottom plate (3) is located at the bottom end of the side wall (2), and the ventilation hole (4) is located downstream of the curved gate (1) And communicate with the cavity area at the top of the water flow after the downstream flood discharge, the first sudden expansion and sudden drop water stop structure is located upstream of the arc gate (1), and the secondary sudden expansion and sudden drop aeration structure is located at the vent hole (1). 4) The junction of the downstream water impact area and the low pressure area. 2. The air-entrained structure according to claim 1, characterized in that, the secondary sudden expansion and sudden drop aerated structure comprises aerated sudden expansion (5) and aerated abrupt drop; the side wall (2) includes The left and right side walls, the downstream sides of the left and right side walls (2) are widened inwardly to form the aerated sudden expansion (5); the water flow produces a drop at the bottom plate (3) and aeration to form the aerated aeration slump. 3. The aerated structure according to claim 2, characterized in that, the aerated sudden expansion (5) is located at 2-3m downstream of the bottom of the arc gate (1), and the left and right side walls (2) The sides are widened inward by 0.5-1m. 4. The air-entraining structure according to claim 2, characterized in that, the one-time sudden expansion and sudden drop water stop structure comprises the water stop sudden expansion (6) upstream of the arc gate (1) and the water stop drop sill at the bottom end (7). 5. The air-entrained structure according to claim 4, characterized in that, the aerated slump comprises a platform (8), a support structure (9) and a ventilation channel (10); the platform (8) is connected to the The water stop sill (7) is erected on the support structure (9) to form a drop with the bottom plate (3); the support structure (9) is located on the bottom plate (3); the ventilation channel (10) is located on the platform Below (8), the front end is connected to the vent hole (4), and the rear end is connected to the bottom cavity of the downstream water flow after flood discharge. 6. The aeration structure according to claim 5, wherein the support structure (9) is a plurality of evenly distributed support columns, and the cavity area between the plurality of support columns forms the ventilation channel (10) . 7. The air-entrained structure according to claim 5, characterized in that, the support structure (9) is a concrete structure with a plurality of pipes arranged vertically and horizontally inside, and the ventilation channels (10) are formed inside the pipes. 8. The air-entrained structure according to claim 5, characterized in that, the length of the platform (8) is 2-3m, and the material is concrete. 9. The air-entrained structure according to claim 4, characterized in that the water-stopping sudden expansion (6) is located on the left and right side walls (2) upstream of the arc gate (1), preferably, the water-stopping The downstream end surface of the protruding expansion (6) is an arc-shaped surface adapted to the arc-shaped gate (1), and the arc-shaped facing side wall (2) extends inward and is connected with the side wall (2) to form the Describe the sudden expansion of water stop (6). 10. The air-entrained structure according to claim 4, wherein the water-stop sill (7) is placed horizontally at the bottom end of the two side walls (2) and is connected with the bottom end of the arc gate (1), Preferably, the side surface of the water-stop sill (7) is an arc-shaped surface adapted to the bottom of the arc-shaped gate (1).

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