Ventilation system for deep draft flood relief gate

Abstract

This utility model discloses a ventilation system, particularly a ventilation system for a deep-type spillway emergency gate, belonging to the field of hydraulic engineering structure design and manufacturing technology. It provides a ventilation system for a deep-type spillway emergency gate that can effectively improve the flow regime of downstream water, thereby effectively reducing cavitation damage. The ventilation system includes a high concrete dam, a deep spillway on the high concrete dam, an emergency maintenance gate structure on the high concrete dam upstream of the deep spillway, and a ventilation hole and a flow regime adjustment structure. The flow regime adjustment structure is arranged on the high concrete dam at the outlet end of the ventilation hole. The ventilation hole is vertically positioned within the high concrete dam downstream of the emergency maintenance gate structure, corresponding to the gate slot position of the emergency maintenance gate structure. The flow regime of the high-speed water flowing downstream of the emergency maintenance gate structure, in conjunction with the deep spillway, is adjusted and stabilized by the flow regime adjustment structure.

Description

Technical Field

[0001] This utility model relates to a ventilation system, and more particularly to a ventilation system for a deep spillway emergency gate, belonging to the field of hydraulic engineering structure design and manufacturing technology. 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) 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.

[0005] 4) Emergency gate An emergency gate is a gate that can cut off the flow of water in flowing water in order to handle accidents that occur downstream of the channel. It is usually installed in front of the working gate of the spillway structure. It is generally closed in flowing water and opened in still water.

[0006] 5) Emergency gate vent The vent hole of the emergency gate is generally located on the downstream side of the emergency gate, and its main functions include: When the emergency gate is closed by flowing water, air is supplied into the flow channel to prevent negative pressure from appearing behind the gate, which could lead to cavitation damage to the gate and gate slot structure. When the emergency gate is opened in still water, the gas in the flow channel is discharged while the downstream working gate is closed and the flow channel between the emergency gate and the working gate is filled with water to ensure the water pressure balance between the upstream and downstream of the emergency gate.

[0007] 2. Deep spillway structure of high concrete dam body.

[0008] 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.

[0009] 3. Typical shapes and main problems of vent holes for emergency gates in deep spillways of high concrete dams. 1) Conventional type of deep spillway, emergency gate, and vent inlet in high concrete dam body For high concrete dams, deep spillway outlets operate under high head and velocity conditions. The vent holes for emergency gates are typically located downstream of the emergency gate slot, at the top curve of the inlet section of the outlet. These outlets usually have the following structural characteristics: The vent hole of the emergency gate is a rectangular hole, arranged parallel to the emergency gate slot, and adopts an equal width structure; The width of the vent hole of the emergency gate is smaller than the width of the hole body section, forming side sills on both sides of the vent hole area and the top of the hole body section of the emergency gate. Downstream of the emergency gate vent, there is a downstream sill formed by the downstream edge of the emergency gate vent and the inlet top curve of the vent body section, and the downstream sill is non-streamlined.

[0010] 2) Main problems The width of the vent hole of the emergency gate is smaller than the width of the gate body section, forming side sills on both sides of the vent hole area and the top of the gate body section. When the water flow passes through the vent hole area at the top of the gate body section, the water flow will split into three streams in the vertical direction: the water flow adhering to the walls of the side sills on both sides, and the water flow entering the vent hole in the middle. The continuity of the water flow at the top of the gate body section is disrupted; the water flows in the middle and on both sides mix with each other, making the flow pattern more turbulent, which is not conducive to the stable control of the water flow in the gate body section.

[0011] Downstream of the vent hole of the emergency gate, there is a downstream sill (non-streamlined) formed by the downstream edge of the emergency gate slot and the top curve of the inlet section of the vent. When the water flows through the upstream corner of the vent hole, the boundary changes abruptly, causing the water flow to diffuse and separate from the sidewall. The diffused water flow entering the vent hole will form a stable vortex. When the diffused water flow passes through the downstream sill of the vent hole, it will separate from the wall again, causing a pressure drop on the downstream side of the downstream sill and at the top curve of the vent section. If the pressure drops to a certain level, it can cause cavitation (i.e., separation cavitation) and cavitation damage at the top of the vent section. Utility Model Content

[0012] The technical problem to be solved by this utility model is to provide a ventilation system for a deep-type spillway emergency gate that can effectively improve the flow pattern of the downstream water flow and thus effectively reduce the degree of cavitation damage.

[0013] The technical solution adopted to solve the above-mentioned technical problems is: a ventilation system for a deep spillway emergency gate, comprising a high concrete dam, a deep spillway on the high concrete dam, and an emergency maintenance gate chamber structure on the high concrete dam upstream of the deep spillway. The ventilation system further includes a vent and a flow-regulating composite adjustment structure. The flow-regulating composite adjustment structure is arranged on the high concrete dam at the outlet end of the vent. The vent is vertically positioned within the high concrete dam downstream of the emergency maintenance gate chamber structure, corresponding to the gate slot position of the emergency maintenance gate chamber structure. The flow pattern of the high-speed water flow discharged under the cooperation of the deep spillway downstream of the emergency maintenance gate chamber structure is adjusted and stabilized by the flow-regulating composite adjustment structure.

[0014] Furthermore, an inlet bracket and an inlet gate pier are installed on the high concrete dam upstream of the deep spillway. The emergency maintenance gate chamber structure is arranged on the high concrete dam upstream of the deep spillway via the inlet bracket and the inlet gate pier. The vent is arranged vertically on the high concrete dam between the inlet gate pier and the basic shape line upstream of the high concrete dam.

[0015] The preferred embodiment of the above scheme is that the width of the vent hole is at least smaller than the width of the deep drainage hole.

[0016] Furthermore, the flow pattern adjustment structure includes at least an adjustment mechanism at the outlet end of the vent. The flow pattern of the high-speed water flow discharged in conjunction with the deep drainage hole at the two sides along the width direction of the outlet end of the vent is adjusted and kept stable by the adjustment mechanism at the outlet end of the vent.

[0017] The preferred embodiment of the above scheme is that the vent outlet adjustment mechanism is an enlarged groove set at the vent outlet along the width direction of the deep drain hole. The width of the enlarged groove is adapted to the width of the deep drain hole, and the side sills between the two sides of the vent outlet along the width direction and the top surface of the deep drain hole are arranged in the enlarged groove.

[0018] Furthermore, the flow regime adjustment structure also includes a cross-sectional flow regime adjustment mechanism, which adjusts and stabilizes the flow regime of the high-speed downstream water flow located on the downstream side of the vent along the flow direction.

[0019] The preferred embodiment of the above scheme is that the cross-sectional flow adjustment mechanism is an arc-shaped streamlined transition sill located on the downstream end face of the vent outlet along the water flow direction and on the downstream end face of the enlarged groove along the water flow direction.

[0020] Furthermore, a corrosion-reducing drop was installed on the high concrete dam at the end of the deep spillway outlet.

[0021] The preferred embodiment of the above scheme is that the corrosion-reducing sill is a vertically bent expansion cavity arranged at the end of the outlet of the deep drainage hole.

[0022] The beneficial effects of this utility model are as follows: The technical solution provided in this application is based on existing high concrete dams, and further combines the structural characteristics of a high concrete dam with a deep spillway and an emergency maintenance gate chamber structure located on the upstream side of the deep spillway. A ventilation hole and a flow-regulating composite adjustment structure are added to form the ventilation system of this application. The flow-regulating composite adjustment structure is then arranged on the high concrete dam at the inlet end of the ventilation hole, and the ventilation hole is vertically positioned within the high concrete dam downstream of the emergency maintenance gate chamber structure, corresponding to the gate slot position of the emergency maintenance gate chamber structure. Finally, the flow pattern of the high-speed water flow discharged under the cooperation of the deep spillway, located downstream of the emergency maintenance gate chamber structure, is adjusted and stabilized by the flow-regulating composite adjustment structure. This effectively improves the flow pattern of the discharged water and effectively reduces the degree of cavitation damage. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the ventilation system for the deep-type spillway emergency gate of this utility model; Figure 2 for Figure 1 AA sectional view.

[0024] The markings in the diagram are: 1. High concrete dam; 2. Deep spillway; 3. Ventilation hole; 4. Inlet corbel; 5. Inlet gate pier; 6. Enlarged groove; 7. Side sill; 8. Arc-shaped streamlined transition sill; 9. Corrosion-reducing drop sill. Detailed Implementation

[0025] like Figure 1 , Figure 2 This invention provides a ventilation system for a deep-type spillway emergency gate, which effectively improves the flow pattern of downstream water and thus reduces cavitation damage. The ventilation system includes a high concrete dam 1, a deep-type spillway 2 on the high concrete dam 1, and an emergency maintenance gate chamber structure on the high concrete dam 1 upstream of the deep spillway 2. The ventilation system also includes a vent 3 and a flow pattern adjustment structure. The flow pattern adjustment structure is located on the high concrete dam 1 at the inlet end of the vent 3. The vent 3 is vertically positioned within the high concrete dam 1 downstream of the emergency maintenance gate chamber structure, corresponding to the gate slot position of the emergency maintenance gate chamber structure. The flow pattern of the high-speed water flowing downstream of the emergency maintenance gate chamber structure, in conjunction with the deep spillway 2, is adjusted and stabilized by the flow pattern adjustment structure. The technical solution provided in this application is based on existing high concrete dams. It incorporates the structural characteristics of a high concrete dam with deep spillway holes and an emergency maintenance gate chamber located upstream of the deep spillway holes. Furthermore, it adds venting holes and a flow regulation adjustment structure to form the ventilation system of this application. The flow regulation adjustment structure is then arranged on the high concrete dam at the inlet end of the venting holes, and the venting holes are vertically positioned within the high concrete dam downstream of the emergency maintenance gate chamber structure, corresponding to the gate slot position. Finally, the flow pattern of the high-speed water flow downstream of the emergency maintenance gate chamber structure, facilitated by the deep spillway holes, is adjusted and stabilized by the flow regulation adjustment structure. This effectively improves the flow pattern of the discharged water and reduces the degree of cavitation damage. In accordance with the existing layout characteristics of deep spillway, this application also provides an inlet bracket 4 and an inlet gate pier 5 on the high concrete dam 1 upstream of the deep spillway 2. The emergency maintenance gate chamber structure is arranged on the high concrete dam 1 upstream of the deep spillway 2 via the inlet bracket 4 and the inlet gate pier 5. The vent 3 is arranged vertically on the high concrete dam 1 between the inlet gate pier 5 and the basic shape line of the upstream of the high concrete dam. Accordingly, the vent 3 provided in this application is at least less wide than the width of the deep spillway 2.

[0026] Accordingly, considering the existing technology and the structural characteristics of existing high concrete dams, the flow regime adjustment structure of this application includes at least a vent outlet adjustment mechanism. The flow regime of the high-speed water flow discharged under the cooperation of the deep spillway 2, located at the two sides along the width direction of the vent outlet, is adjusted and stabilized by the vent outlet adjustment mechanism. Preferably, the vent outlet adjustment mechanism is an enlarged groove 6 located at the vent outlet along the width direction of the deep spillway. The width of the enlarged groove 6 is adapted to the width of the deep spillway 2, and the side sills 7 between the two sides along the width direction of the vent outlet and the top surface of the deep spillway are arranged within the enlarged groove 6. Furthermore, to maximize the flow regime of the high-speed discharged water flow, the flow regime adjustment structure of this application also includes a cross-sectional flow regime adjustment mechanism. The flow regime of the high-speed discharged water flow located at the downstream side of the vent 3 along the water flow direction is adjusted and stabilized by the cross-sectional flow regime adjustment mechanism. The preferred embodiment is that the cross-sectional flow adjustment mechanism is an arc-shaped streamlined transition sill 8 located on the downstream end face of the vent outlet along the water flow direction and on the downstream end face of the enlarged groove along the water flow direction.

[0027] Meanwhile, in order to minimize the cavitation and damage to the high concrete dam caused by the downstream water flow, this application also provides a corrosion-reducing drop 9 on the high concrete dam 1 at the outlet end of the deep spillway. Preferably, the corrosion-reducing drop 9 is a vertically bent expansion cavity arranged at the outlet end of the deep spillway.

[0028] In summary, the technical solution provided in this application also has the following advantages: 1) The continuity and stability of the water flow at the top of the orifice section are good. Because the vent of the emergency gate adopts a structure that is narrow at the top and wide at the bottom, the width of the lower section of the vent is the same as the width of the orifice section. When the water flow at the top of the orifice section passes through the lower section of the vent, the water flow will no longer split in the vertical direction of the water flow, thus ensuring the continuity of the water flow. In addition, since there is no longer any mixing of water flow in the middle and on both sides, the flow pattern and stability of the water flow are also improved.

[0029] 2) Cavitation at the top of the downstream section of the emergency gate vent is reduced. Because the downstream edge of the emergency gate vent uses a streamlined curve connected to the top curve of the vent inlet, the downstream section of the vent is a streamlined sill. Therefore, when the diffused water flow entering the emergency gate vent passes through this streamlined sill downstream, the water flow will adhere to the streamlined sill and the top curve of the vent inlet to the greatest extent possible, significantly reducing the possibility of the water flow separating from the sidewall and causing cavitation.

[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 a vent structure for an accident gate of a deep spillway in a high concrete dam that can improve the continuity and stability of water flow at the top of the vent section and effectively reduce the separation and cavitation at the top of the downstream vent section.

[0031] The technical solution adopted by 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) The vent hole of the emergency gate of the deep spillway of the high concrete dam has the following structural features: 1) The vent hole of the emergency gate is a rectangular hole, arranged parallel to the slot of the emergency gate; 2) The vent hole of the emergency gate adopts a structure that is narrow at the top and wide at the bottom. The width of the upper section of the vent hole is less than the width of the hole body section, and the width of the lower section of the vent hole is the same as the width of the hole body section. A side sill is formed at the location of the abrupt change in cross-section, and the side sill is located above the basic shape of the hole body section and outside the influence range of the main flow of the hole body section. 3) The downstream edge of the vent hole of the emergency gate adopts a streamlined curve that connects to the top curve of the inlet of the hole body, that is, the downstream of the vent hole of the emergency gate is a streamlined sill.

Claims

1. A ventilation system for a deep spillway emergency gate, comprising a high concrete dam (1), a deep spillway (2) provided on the high concrete dam (1), and an emergency maintenance gate chamber structure provided on the high concrete dam (1) upstream of the deep spillway, characterized in that: The ventilation system also includes a ventilation hole (3) and a flow state composite adjustment structure. The flow state composite adjustment structure is arranged on the high concrete dam (1) at the outlet end of the ventilation hole (3). The ventilation hole (3) is set in the high concrete dam (1) on the downstream side of the emergency maintenance gate structure in a vertical direction, which is adapted to the gate slot position of the emergency maintenance gate structure. The flow state of the high-speed water flow discharged under the cooperation of the deep discharge hole (2) on the downstream side of the emergency maintenance gate structure is adjusted and kept stable by the flow state composite adjustment structure.

2. The ventilation system for a deep spillway emergency gate according to claim 1, characterized in that: An inlet bracket (4) and an inlet gate pier (5) are also installed on the high concrete dam (1) upstream of the deep spillway (2). The emergency maintenance gate chamber structure is arranged on the high concrete dam (1) upstream of the deep spillway (2) through the inlet bracket (4) and the inlet gate pier (5). The ventilation hole (3) is arranged vertically on the high concrete dam (1) between the inlet gate pier (5) and the basic shape line upstream of the high concrete dam.

3. The ventilation system for a deep spillway emergency gate according to claim 2, characterized in that: At least the width of the vent (3) is smaller than the width of the deep drain hole (2).

4. The ventilation system for a deep spillway emergency gate according to claim 2 or 3, characterized in that: The flow regime adjustment structure includes at least an adjustment mechanism at the outlet end of the vent. The flow regime of the high-speed water flow discharged under the cooperation of the deep drainage hole (2) at the two sides along the width direction at the outlet end of the vent is adjusted and kept stable by the adjustment mechanism at the outlet end of the vent.

5. The ventilation system for a deep spillway emergency gate according to claim 4, characterized in that: The vent outlet adjustment mechanism is an enlarged groove (6) set at the vent outlet along the width direction of the deep drain hole. The width of the enlarged groove (6) is adapted to the width of the deep drain hole (2). The side sills (7) between the two sides of the vent outlet along the width direction and the top surface of the deep drain hole are arranged in the enlarged groove (6).

6. The ventilation system for a deep spillway emergency gate according to claim 5, characterized in that: The flow regime adjustment structure also includes a cross-sectional flow regime adjustment mechanism. The flow regime of the high-speed downstream water flow located at the downstream end face of the vent (3) along the water flow direction is adjusted and kept stable by the cross-sectional flow regime adjustment mechanism.

7. The ventilation system for a deep spillway emergency gate according to claim 6, characterized in that: The cross-sectional flow adjustment mechanism is an arc-shaped streamlined transition sill (8) set at the downstream end face of the vent outlet along the water flow direction and at the downstream end face of the enlarged groove along the water flow direction.

8. The ventilation system for a deep spillway emergency gate according to claim 7, characterized in that: A corrosion-reducing drop (9) is also installed on the high concrete dam (1) at the end of the deep spillway outlet.

9. The ventilation system for a deep spillway emergency gate according to claim 8, characterized in that: The corrosion-reducing drop (9) is a vertically bent expansion cavity arranged at the end of the outlet of the deep drainage hole.

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