Multifunctional discharge hole arrangement structure and regulation and control method

Abstract

The invention provides a multifunctional discharge hole arrangement structure, which is characterized in that an arc gate water discharge pipe is closely arranged at the downstream of a main hole of a diversion discharge hole connected with a lower reservoir, a working arc gate is arranged on a discharge path of the arc gate water discharge pipe, and the arc gate water discharge pipe is connected with an energy dissipater at the downstream side of the working arc gate; a cone valve blow-off pipe and an ecological blow-off pipe are arranged beside the radial gate blow-off pipe, a working cone valve and a working flow adjusting valve are arranged on the discharge path of the cone valve blow-off pipe and the discharge path of the ecological blow-off pipe respectively, and water outlets of the cone valve blow-off pipe and the ecological blow-off pipe are connected with energy dissipation structures. According to the drainage hole arrangement structure, different drainage flow requirements can be met, different drainage structures can be used, it can be guaranteed that the river flow is within a reasonable range, and the service life of each structure is prolonged. And therefore, the situation that the safety of the gate and a power station is affected due to the fact that torrent oscillation generated by long-term discharge work of the radial gate with small opening degree is harmful to the safety of the gate and the power station can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of power station discharge engineering, and in particular to a multifunctional discharge hole arrangement structure and a control method. Background Art

[0002] When the water level reaches the flood discharge elevation, the spillway or a higher-elevation dam discharge structure can be activated. If the water level does not reach the flood discharge elevation, the lower-elevation flood discharge tunnel is used to discharge the floodwater. This flood discharge tunnel has a high operating head and is a pressurized tunnel, typically with high flow velocities, requiring appropriate energy dissipation structures downstream. To ensure ecological flow in the downstream river, the flood discharge tunnel often also functions to discharge ecological flow. When other flood discharge structures are insufficient, the flood discharge tunnel discharges a certain amount of flow, fulfilling the task of ensuring ecological flow. However, opening the gates to release water under high pressure can cause torrent vibrations due to coupled vibrations between the water flow and the structure. This problem is extremely complex and difficult to calculate theoretically. Most research relies on observations of prototype power plants to analyze vibrations, stresses, and displacements. Pre-flood discharges typically require large flow rates, and the design flow rate influences the design of the tunnel and gates. However, the ecological flow requirement is typically low. Long-term use of large gates with small openings to discharge ecological flow inevitably leads to vibration problems, impacting the safety and service life of the power plant. Summary of the Invention

[0003] The first object of the present invention is to provide a discharge hole arrangement structure that can effectively meet various discharge flow requirements. To this end, the present invention adopts the following technical solutions:

[0004] A multifunctional discharge hole arrangement structure, in which an arc gate discharge pipe is arranged immediately downstream of the main tunnel of the diversion discharge hole connected to the lower reservoir, the arc gate discharge pipe is provided with a working arc gate on its discharge path, and the arc gate discharge pipe is connected to an energy dissipator on the downstream side of the working arc gate; a cone valve discharge pipe and an ecological discharge pipe are arranged on the side of the arc gate discharge pipe, the cone valve discharge pipe and the ecological discharge pipe are provided with a working cone valve and a working flow regulating valve respectively on their discharge paths, and the water outlets of the cone valve discharge pipe and the ecological discharge pipe are both connected to an energy dissipation structure; the discharge flow of water flowing through the working arc gate, the working cone valve and the working flow regulating valve is divided into three levels from high to low, so as to form a separate fully open discharge state of the valve or gate corresponding to different discharge flow requirements.

[0005] Furthermore: a drainage channel pipe is provided on the branch of the arc gate drainage pipe, and the water inlets of the cone valve drainage pipe and the ecological drainage pipe are uniformly connected to the drainage channel pipe.

[0006] Furthermore: the cone valve discharge pipe and the ecological discharge pipe are connected to the same stilling pool on the downstream side of the valve.

[0007] Furthermore: an emergency eccentric hemispherical valve is provided on the water discharge channel pipe.

[0008] Furthermore, the inner diameters of the arc gate drain pipe, the cone valve drain pipe and the ecological drain pipe decrease in sequence.

[0009] The second object of the present invention is to provide a method for regulating and controlling the discharge flow rate to ensure reasonable discharge flow under different discharge requirements. To this end, the present invention adopts the following technical solutions:

[0010] A control method for a multifunctional discharge hole arrangement structure includes the following contents:

[0011] When a major flood occurs, the working cone valve and the working flow regulating valve are closed, and the working arc gate is fully opened to discharge flood water. The water body flows into the downstream ditch or river after dissipating energy through the energy dissipator;

[0012] When a small flood occurs or a flood is forecasted, the working arc gate and the working flow regulating valve are closed, and the working cone valve is opened to discharge the flood or pre-discharge, and the water body flows into the downstream ditch or river after dissipating energy in the energy dissipation pool;

[0013] During the dry season or very small floods, the working flow regulating valve can be used for ecological water replenishment or fully opened for small flood pre-discharge. The water body flows into the downstream ditch or river after dissipating energy in the energy dissipation pool.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The discharge hole arrangement structure of the present invention can be adapted to meet different discharge flow requirements, allowing the use of different discharge structures, ensuring that river flow remains within a reasonable range and extending the service life of each structure. This also prevents the use of radial gates with small openings for long periods of time, which can cause turbulent flow oscillations and endanger the safety of the gates and power stations. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] The markings in the attached figure are: 1-main tunnel of diversion and discharge tunnel; 2-arc gate discharge pipe; 3-working arc gate; 4-discharge channel pipe; 5-cone valve discharge pipe; 6-ecological discharge pipe; 7-accident eccentric semi-ball valve; 8-working cone valve; 9-working flow regulating valve; 10-stilling pool; 11-energy dissipation worker. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and examples, but they are not intended to limit the present invention.

[0019] like Figure 1As shown, a multifunctional discharge hole arrangement structure is shown. The upstream of the diversion discharge hole main hole 1 is connected to the lower reservoir. An arc gate discharge pipe 2 is immediately arranged downstream of the diversion discharge hole main hole 1. The arc gate discharge pipe 2 is provided with a working arc gate 3 on its discharge path, and the working arc gate 3 is correspondingly arranged in the arc gate room. The arc gate discharge pipe 2 is connected to the energy dissipator 11 on the downstream side of the working arc gate 3; a cone valve discharge pipe 5 and an ecological discharge pipe 6 are arranged on the side of the arc gate discharge pipe 2. The cone valve discharge pipe 5 and the ecological discharge pipe 6 are arranged on the discharge path of the arc gate discharge pipe 2. A working cone valve 8 and a working flow regulating valve 9 are respectively provided on the path, and the outlets of the cone valve discharge pipe 5 and the ecological discharge pipe 6 are connected with energy dissipation structures; the discharge flow of the water body flowing through the working arc gate 3, the working cone valve 8 and the working flow regulating valve 9 is divided into three levels from high to low, and three independent discharge channels are formed for the discharge water body through the arc gate discharge pipe 2, the cone valve discharge pipe 5 and the ecological discharge pipe 6, so as to form a separate fully open discharge state of the valve or gate corresponding to different discharge flow requirements.

[0020] A drainage channel pipe 4 branches off the arc-gate drain pipe 2. A cone valve drain pipe 5 and an ecological drain pipe 6 branch off this drain pipe 4. The water inlets of both the cone valve drain pipe 5 and the ecological drain pipe 6 are connected to the drain pipe 4. This allows the working cone valve 8 and the working flow regulating valve 9 to be arranged in the same valve chamber. Furthermore, the cone valve drain pipe 5 and the ecological drain pipe 6 connect to the same stilling basin 10 downstream of their valves.

[0021] Correspondingly, the inner diameter of the arc gate drain pipe 2 is larger than the inner diameter of the cone valve drain pipe 5 , and the inner diameter of the cone valve drain pipe 5 is larger than the inner diameter of the ecological drain pipe 6 .

[0022] The drain channel pipe 4 is provided with an emergency eccentric hemispherical valve 7, which is arranged upstream of the cone valve drain pipe 5 and the ecological drain pipe 6. If the cone valve drain pipe 5 and the ecological drain pipe 6 and their valves have an accident or need maintenance, the emergency eccentric hemispherical valve 7 can be closed to block the water flow.

[0023] In this embodiment, the calculation content of the control process is as follows:

[0024] 1. The working arc gate 3 is used for large flow discharge. At the maximum discharge flow Q1, the orifice size is fully opened according to the arc gate opening, and the orifice flow velocity v1 is 8m / s-15m / s.

[0025] The calculation formula for the flood discharge orifice flow velocity v is as follows:

[0026]

[0027] Where, H is the water head at the inlet of the spillway (m); φ is the velocity coefficient; g is the acceleration of gravity (9.81m / s 2); v1 is the flow velocity at the inlet section (m / s); h1 is the water depth at the inlet section (m).

[0028] The orifice size is usually the initial selection of the cross-sectional area of the arc gate discharge pipe. Therefore, 60% of the tunnel area S = arc gate orifice area (height H×width B) = Q1 / v1.

[0029] 2. The diameter D of the cone valve discharge pipe is determined according to the flow rate Q2 of the flood that occurs once a year for 1-5 years and the flow velocity v2 in the pipe is determined according to 5m / s-8m / s. However, the maximum discharge volume is not more than 20m 3 / s is controlled, and the water passing through the working cone valve 8 enters the energy dissipation pool 10 for re-efficiency and then flows out of the energy dissipation pool 10 and flows into the downstream ditch or river.

[0030] 3. The discharge flow of the ecological discharge pipe 6 is determined according to the flow that meets the requirements of ecological water replenishment, which is usually the excess flow Q3 in a normal water year or the discharge flow required to be completed within 24 hours in the rainy season. The maximum value is taken for comprehensive determination, and the flow velocity v3 in the pipe is determined as 3m / s-5m / s. The water body 9 passing through the working flow regulating valve is dissipated through the energy dissipation pool 10 and then flows into the downstream ditch or river.

[0031] Based on the above, the flow rate calculation formula flowing through the working cone valve 8 and the working flow regulating valve 9 is as follows:

[0032]

[0033] Where c q ——Flow coefficient; A0——Valve port flow area (m 2 ); △p——pressure difference before and after the valve port (Pa); ρ——liquid density (kg / m 3 ).

[0034] Accordingly, the calculation formula for the size of the stilling basin 10 is as follows:

[0035] S=h c ”-h t (3)

[0036] L k =L d +0.8L j (4)

[0037] Where, S is the depth of the stilling pool (m); h is c "——Water depth after the jump (m); h t ——downstream water depth (m); L k ——Pool length (m); L d ——water tongue length (m); L j ——Hydraulic jump length (m).

[0038] Based on the above content, this implementation case provides a discharge hole arrangement structure with specific values:

[0039] The main diversion and discharge tunnel 1 is 20.3m long and 6m in diameter, and the arc gate discharge pipe 2 is 8.7m long and has the same diameter as the main diversion and discharge tunnel 1. The arc gate opening area is 18m 2 (4m wide x 4.5m high). Drain channel pipe 4 is 14.8m long and 3m in diameter. The cone valve drain pipe 5 has the same diameter as drain channel pipe 4 and is 4.2m long. The ecological drain pipe 6 is 7.2m long and 1.1m in diameter. The working cone valve 8 has a diameter of 2.6m, the working flow regulating valve 9 has a diameter of 0.8m, and the emergency eccentric hemispherical valve 7 has a diameter of 2.6m. The stilling basin 10 measures 7m x 9.5m.

[0040] Combined with the dimensions of the above-mentioned discharge hole arrangement structure and the calculation method of the control process, when the discharge hole arrangement structure is used for discharge control, the specific discharge control method and whether it can meet the corresponding requirements are as follows:

[0041] (1) When there is no early flood discharge task:

[0042] The working arc gate 3 is closed, the working cone valve 8 is closed, the working flow regulating valve 9 and the emergency eccentric semi-ball valve 7 are working, and the water is discharged through the discharge channel pipe 4 and the ecological discharge pipe 6;

[0043] The ecological flow discharge requirement of the power station is not less than 0.05m 3 , the working flow regulating valve 9 is fully opened, and the flow rate is calculated by combining the above formula (2):

[0044]

[0045] At this time, the water in the working flow regulating valve 9 dissipates energy through the stilling pool 10 and then flows downstream. According to the size of the stilling pool 10 and the above formulas (3) and (4), the water depth of the stilling pool 10 under the maximum discharge flow is calculated as follows:

[0046] S=h c ”-h t =0.109-0.1=0.009m;

[0047] L k =L d +0.8L j =2.195+0.8×0.191=2.348<9.5m, then the size of stilling pool 10 meets the requirements.

[0048] (2) When encountering a minor flood or a flood warning:

[0049] Based on the required storage capacity to be released in advance, the time to open the working cone valve 8 to release the flow is determined. The working cone valve 8 and the emergency eccentric hemispherical valve 7 are opened, and the working arc gate 3 and the working flow regulating valve 9 are closed. The water is then released through the discharge channel 4 and the cone valve discharge pipe 5.

[0050] The water level is required to be lowered by 6m, and the discharge capacity is 1.1806 million m 3 , the working cone valve 8 is fully opened, the accident eccentric semi-ball valve 7 is opened, and the discharge flow is shown in the table:

[0051] Table 1 Working cone valve discharge flow and duration

[0052] Elevation (m) 325 326 327 328 331 <![CDATA[Storage capacity (10,000 m 3 )]]> 696.29 721.03 748.75 792.46 814.35 <![CDATA[Discharge (m 3 / s)]]> 15.96 16.13 16.85 17.66 19.83 Time (hours) 0.30 0.31 0.49 0.45 0.60

[0053] At this time, the water in the working cone valve 8 dissipates energy through the stilling pool 10 and then discharges to the downstream. According to the size of the stilling pool 10 and the above formulas (3) and (4), the water depth of the stilling pool 10 under the maximum discharge flow is calculated as follows:

[0054] S=h c ”-h t =1.937-0.5=1.437m;

[0055] L k =L d +0.8L j =7.207+0.8×2.401=9.128m<9.5m, then the size of stilling pool 10 meets the requirements.

[0056] (3) When a major flood occurs and it is necessary to release water in advance:

[0057] Floods under the design standard rarely occur. Before the onset of continuous heavy rainfall, it is necessary to release the flow. The release requirement of the working cone valve 8 is no longer met, so the working arc gate 3 is opened to release the flow. The release requires the water level to drop by 20m, and the release capacity is 4.0601 million m 3 According to the storage capacity that needs to be released in advance, the time to open the working arc gate 3 to release the flow is obtained. Open the working arc gate 3, close the working cone valve 8 and the working flow regulating valve 9. When the working arc gate 3 is fully opened, the discharge flow and time are as follows:

[0058] Table 2 Working arc gate discharge flow and duration

[0059] Elevation (m) 311 313 318 323 331 <![CDATA[Storage capacity (10,000 m 3 )]]> 408.34 416.95 451.33 615.16 814.35 <![CDATA[Discharge (m 3 / s)]]> 141.59 143.12 149.08 152.77 162.35 Time (hours) 1.09 1.18 1.35 1.36 1.21

[0060] Based on the above, to monitor the safety of various structures, stress sensors for detecting water pressure can be embedded in gates, valves, and pipes. During the operation of this implementation case, only minor stress fluctuations and vibrations were detected, which has a significant effect on maintaining the safe operation of the power station.

[0061] The above embodiment is only a preferred technical solution of the present invention. Those skilled in the art should understand that the technical solutions or parameters in the embodiment can be modified or replaced without departing from the principle and essence of the present invention, and all should be covered by the protection scope of the present invention.

Claims

1. A multifunctional discharge hole arrangement structure, characterized by: An arc gate drain pipe (2) is provided immediately downstream of the main diversion discharge tunnel (1), a working arc gate (3) is provided on the discharge path of the arc gate drain pipe (2), and the arc gate drain pipe (2) is connected to an energy dissipator (11) on the downstream side of the working arc gate (3); A cone valve discharge pipe (5) and an ecological discharge pipe (6) are provided on the side of the arc gate discharge pipe (2); the cone valve discharge pipe (5) and the ecological discharge pipe (6) are provided with a working cone valve (8) and a working flow regulating valve (9) respectively on their discharge paths; the water outlets of the cone valve discharge pipe (5) and the ecological discharge pipe (6) are both connected to an energy dissipation structure; the discharge flow of the water body flowing through the working arc gate (3) and the working cone valve (8) and the working flow regulating valve (9) is divided into three levels from high to low, so as to form a separate fully open discharge state of the valve or gate corresponding to different discharge flow requirements.

2. A multifunctional discharge hole arrangement structure according to claim 1, characterized in that: The upper branch of the arc gate drain pipe (2) is provided with a drain channel pipe (4), and the water inlets of the cone valve drain pipe (5) and the ecological drain pipe (6) are uniformly connected to the drain channel pipe (4).

3. The multifunctional discharge hole arrangement structure according to claim 2, characterized in that: The cone valve discharge pipe (5) and the ecological discharge pipe (6) are connected to the same stilling pool (10) at the downstream side of the valves.

4. The multifunctional discharge hole arrangement structure according to claim 2, characterized in that: The drain channel pipe (4) is provided with an emergency eccentric hemispherical valve (7).

5. The multifunctional discharge hole arrangement structure according to claim 1, characterized in that: The inner diameters of the arc gate drain pipe (2), the cone valve drain pipe (5), and the ecological drain pipe (6) decrease in sequence.

6. A method for controlling a multifunctional discharge hole arrangement structure, characterized in that: The multifunctional discharge hole arrangement structure according to any one of claims 1 to 5 is used for hierarchical regulation, including the following contents: When a major flood occurs, the working cone valve (8) and the working flow regulating valve (9) are closed, and the working arc valve (3) is fully opened to discharge the flood; When a small flood occurs or a flood is forecast to come, the working arc gate (3) and the working flow regulating valve (9) are closed, and the working cone valve (8) is opened to discharge the flood or pre-discharge; During the dry season or very small floods, the working flow regulating valve (9) can be used for ecological water replenishment or fully opened for small flood pre-discharge.

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