Water level self-control type regulating reservoir for water conveyance project

Abstract

The utility model provides a water level self-control type regulating reservoir for a water conveyance project, and relates to the technical field of water conservancy projects. A regulating tank is arranged at the highest position of a downstream water delivery pipe of a pump station, front and rear pipelines of the regulating tank are separated into a water inlet pipe and a water outlet pipe, and an overflow weir is arranged in the regulating tank to divide the water tank into an upstream tank and a downstream tank, so that the water level of the upstream tank is more than one meter higher than the top elevation of the water inlet pipe, and gas-liquid separation at the highest position of the water delivery pipe is effectively avoided; when the pump station is powered off due to accidents, dangerous water hammer pressure of the pump station can be effectively prevented, and normal and safe operation of the pump station cannot be affected even if gas-liquid two-phase flow is generated by the water outlet pipe at the downstream of the adjusting tank.

Description

Technical Field

[0001] The utility model relates to the technical field of water conservancy projects, and particularly relates to a water level self-controlled regulating pond for a water conveyance project. Background Technique

[0002] With the development needs of social economy, the demand for water resources is increasing day by day, and the reasonable planning and allocation of regional water resources is becoming increasingly important. The development of urban and rural water supply basically needs to be realized through long-distance water diversion projects.

[0003] When using pressure pipelines for long-distance water conveyance, the undulating elevation difference of the pipeline route has a decisive impact on the installed capacity scale of the pressurized pumping stations set up, and the reasonable and scientific setting of pipeline auxiliary facilities has a decisive impact on the operation safety and reliability of the water conveyance system.

[0004] According to the overall layout trend of the water conveyance route, it is relatively common that the longitudinal elevation of the pipeline rises monotonously, and the pressurized pumping stations and pipeline auxiliary facilities are designed with the starting and terminal points as the control elevation differences; however, considering factors such as the engineering terrain and geological changes, the impact of land acquisition and demolition, construction, and environmental conditions, there is a situation where the longitudinal elevation of the pipeline drops to the pipeline end point after reaching a high point. From the perspective of energy conservation, the descending section can use gravity flow for water conveyance according to its length and the elevation difference between the high point of the pipeline and the outlet; the pressurized pumping stations and pipeline auxiliary facilities are designed with the high point as the control elevation difference, and the length of the pressurized section pipeline can be determined according to the conditions for subsequent gravity water conveyance. According to the calculation results of the transient process of the long-distance pipeline, air valves are generally set at the high point of the pipeline to achieve air intake and exhaust.

[0005] However, in this type of pipeline layout, when the pumping station has an accident power outage, water hammer or water shock phenomena will occur, endangering the safety of the pumping station; even when the water pump is operating normally, gas-liquid two-phase flow is likely to occur at the high point position of the water conveyance pipe and the subsequent descending section, which will also endanger the safety of the pumping station and affect the operation safety of the project. Content of the Utility Model

[0006] Aiming at the deficiencies of the prior art, the utility model provides a water level self-controlled regulating pond for a water conveyance project, which solves the problem that the elevation fluctuation of the water conveyance pipe in the water conveyance project is likely to endanger the safety of the pumping station.

[0007] To achieve the above purposes, the utility model is realized through the following technical solutions:

[0008] A water level self-controlled regulating pond for a water conveyance project. The utility model provides a water level self-controlled regulating pond for a water conveyance project. The regulating pond is arranged at the highest point of the water conveyance pipe downstream of the pumping station. The regulating pond includes: a water pond;

[0009] An inlet is opened on the upstream pool wall of the water pond, and the water inlet pipe is connected to the water pond through the inlet; an outlet is opened on the downstream pool wall of the water pond, and the water outlet pipe is connected to the water pond through the outlet;

[0010] An overflow weir perpendicular to the water flow direction is provided in the middle of the pool, and the overflow weir divides the pool into an upstream pool and a downstream pool.

[0011] Preferably, the flow rate Q of the inlet pipe is known, and the elevation of the top of the inlet pipe and the elevation of the top of the outlet pipe satisfy:

[0012] Z in = Z o ;

[0013] where Z in is the elevation of the top of the inlet pipe;

[0014] Z o is the elevation of the top of the outlet pipe.

[0015] Preferably, the elevation of the top of the overflow weir satisfies:

[0016] Z y ≥ Z in + 1;

[0017] where Z y is the elevation of the top of the overflow weir.

[0018] Preferably, in order to avoid the occurrence of vortices or suction funnels at the water outlet, the minimum submergence depth of the top of the outlet pipe satisfies:

[0019] S = CVD 1 / ;

[0020] where S is the minimum submergence depth of the top of the outlet pipe;

[0021] C is a coefficient related to the geometric shape of the water outlet. When the water outlet is designed with good flow symmetry, C takes 0.55; when the boundary is complex and the lateral flow exists, C takes 0.73.

[0022] V is the flow velocity of the water in the outlet pipe;

[0023] D is the diameter of the outlet pipe;

[0024] In order to ensure that no air enters the outlet pipe, the water level in the downstream pool needs to satisfy:

[0025] H i ≥ Z o + S;

[0026] where H o is the water level height of the downstream pool.

[0027] Preferably, a flow regulating valve is provided at the end of the outlet pipe, and by controlling the opening of the flow regulating valve in real time, H o ≥ Z o + S.

[0028] Preferably, when the overflow weir is a free outfall, the relationship between the flow rate of the inlet pipe and the water level height of the upstream pool satisfies:

[0029]

[0030] where B is the width of the overflow weir, i.e., the net width of the pool;

[0031] μ is the overflow discharge coefficient, generally between 0.36 and 0.5;

[0032] g is the acceleration due to gravity;

[0033] H s is the water level height of the upstream pool.

[0034] Preferably, μ is taken as 0.36 and 0.5 respectively for calculation and comparison to obtain the possible maximum water level H of the upstream pool smax ;

[0035] The elevation Z of the top of the side wall of the pool w > H smax .

[0036] The present utility model provides a water level self-controlled regulating pool for a water conveyance project. Compared with the prior art, it has the following beneficial effects:

[0037] In the present utility model, a regulating pool is arranged at the highest point of the downstream water conveyance pipe of the pump station. The pipes before and after the regulating pool are isolated into an inlet pipe and an outlet pipe. An overflow weir is arranged in the regulating pool to divide the pool into an upstream pool and a downstream pool, so that the water level of the upstream pool is more than one meter higher than the top elevation of the inlet pipe, effectively avoiding the phenomenon of gas-liquid separation at the highest point of the water conveyance pipe; when the pump station has an accident and power failure occurs, it can effectively prevent the dangerous water hammer pressure of the pump station, and even if a gas-liquid two-phase flow occurs in the outlet pipe downstream of the regulating pool, it will not affect the normal and safe operation of the pump station. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 is the longitudinal sectional view of the regulating pool in Embodiment 1 of the present utility model;

[0040] Figure 2 is Figure 1 the sectional view taken along A-A in

[0041] Figure 3This is the longitudinal elevation undulation characteristic diagram of the water conveyance pipeline in Embodiment 2 of the present utility model.

[0042] In the figure, the attached drawing reference numerals are set as follows: water tank 1, water inlet 2, water outlet 3, overflow weir 4. Detailed implementation manners

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be described clearly and completely. Apparently, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0044] The embodiment of the present application provides a water level self-controlled regulating pond for a water conveyance project, which solves the problem that the elevation fluctuation of the water conveyance pipe in the water conveyance project easily endangers the safety of the pumping station.

[0045] To better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the accompanying drawings of the specification and specific implementation manners.

[0046] Embodiment 1:

[0047] As Figure 1 、 Figure 2 shown, the present utility model provides a water level self-controlled regulating pond for a water conveyance project. The regulating pond is arranged at the highest point of the water conveyance pipe downstream of the pumping station. The regulating pond includes: a water tank 1;

[0048] An inlet 2 is provided on the upstream pool wall of the water tank 1, and the water inlet pipe with an increasing upstream elevation is communicated with the water tank 1 through the inlet 2; an outlet 3 is provided on the downstream pool wall of the water tank 1, and the water outlet pipe with a decreasing downstream elevation is communicated with the water tank 1 through the outlet 3;

[0049] An overflow weir 4 perpendicular to the water flow direction is arranged in the middle of the water tank 1, and the overflow weir 4 divides the water tank into an upstream pool and a downstream pool.

[0050] The flow rate Q of the water inlet pipe is known, and the top elevation of the water inlet pipe and the top elevation of the water outlet pipe satisfy:

[0051] Z in = Z o ;

[0052] Among them, Z in is the top elevation of the water inlet pipe;

[0053] Z o is the top elevation of the water outlet pipe.

[0054] To meet the design requirements of the water diversion project, the water pressure at the top of the inlet pipe of the regulating pond should not be less than one meter. Therefore, the elevation of the overflow weir top satisfies:

[0055] Z y ≥Z in +1;

[0056] Among them, Z y is the elevation of the overflow weir top.

[0057] To avoid the occurrence of vortices or suction funnels at the outlet 3, the minimum submergence depth of the top of the outlet pipe satisfies:

[0058] S = CVD 1 / ;

[0059] Among them, S is the minimum submergence depth of the top of the outlet pipe;

[0060] C is a coefficient related to the geometric shape of the outlet. When the outlet is designed with good water flow symmetry, C takes 0.55; when the boundary is complex with lateral water flow, C takes 0.73.

[0061] V is the water flow velocity in the outlet pipe;

[0062] D is the diameter of the outlet pipe;

[0063] To ensure that no air enters the outlet pipe, the water level in the downstream pond needs to satisfy:

[0064] H o ≥Z o +S;

[0065] Among them, H o is the water level height of the downstream pond.

[0066] A flow regulating valve is provided at the end of the outlet pipe. By controlling the opening of the flow regulating valve in real time to maintain H o ≥Z o +S, it can effectively avoid the occurrence of gas-liquid two-phase flow in the outlet pipe. At this time, the overflow weir may form submerged outflow.

[0067] If no flow regulating valve is installed in the outlet pipe, the water level in the downstream pond often drops below the threshold, resulting in gas-liquid two-phase flow in the outlet pipe. At this time, the flow rate of the inlet pipe is less than that of the outlet pipe, and the water level in the downstream pond drops significantly, making the overflow weir a free outflow; due to the layout of the regulating pond, under normal operating conditions, the water level in the upstream pond is always higher than the elevation of the overflow weir top, and the gas-liquid two-phase flow in the outlet pipe has little impact on the pumping station.

[0068] When the overflow weir is in free outflow, the relationship between the flow rate of the inlet pipe and the water level height of the upstream pond satisfies:

[0069]

[0070] Among them, B is the width of the overflow weir, that is, the net width of the pool;

[0071] μ is the overflow discharge coefficient, generally between 0.36 and 0.5;

[0072] g is the acceleration of gravity;

[0073] H s is the water level height of the upstream pool.

[0074] Considering the width of the overflow weir, the pipe diameter of the inlet pipe, the pipe diameter of the outlet pipe and certain installation and maintenance requirements on both sides, μ is taken as 0.36 and 0.5 respectively for calculation and comparison, and the possible highest water level H of the upstream pool water level is obtained smax ;

[0075] The elevation Z of the top of the pool side wall w >H smax .

[0076] Example 2:

[0077] As Figure 3 shown, a certain project is a cross-regional water diversion project. The water intake source and the water diversion terminal both utilize existing reservoirs. The total length of the water conveyance line is 52.66 km, and the starting and ending stake numbers are K0+000~K52+660; the lowest water level of the starting water intake is 53.0 m, the water level of the terminal reservoir is 47.3 m, the terrain along the line first descends and then rises, and the water conveyance method adopts gravity flow combined with pumping station pressurized flow. The maximum water intake flow of the pumping station is 6.944 m 3 / s. Gravity flow is adopted between the stake numbers K0+000~K34+750. A flow regulating valve is set at the end of the gravity flow pipeline, and a water diversion port and a branch regulating valve are provided at K18+520; pressurized flow is adopted between K34+750~K52+660. The end of the gravity flow is connected to the forebay of the pumping station, and a hydraulic control butterfly valve is set at the outlet of the pump of the pumping station. After the pumping station pressurizes, the water conveyance pipeline is at the same elevation and the highest between the stake numbers K50+460~K51+170, about 1.5~2.2 km away from the water conveyance terminal, and the center elevation of the pipe is 53.0 m. Then the elevation of the line gradually decreases and is connected to the terminal reservoir, and the center elevation of the end drops to 43.0 m. The operation water level range of the pumping station needs to be controlled by the high point between K50+460~K51+170.

[0078] After the water conveyance pipeline of the pumping station in this project is at the same elevation and the highest between the stake numbers K50+460~K51+170, the center elevation of the pipe is 53.0 m, and the top elevation of the pipe is 54.2 m. Then the elevation of the line gradually decreases and is connected to the terminal reservoir, and the center elevation of the end drops to 43.0 m, and the top elevation of the pipe is 44.2 m.

[0079] The Design Standard for Outdoor Water Supply stipulates that under various design operating conditions, negative pressure should not occur in the pipeline. The Design Guide for Water Diversion Projects stipulates that when using a pressure pipe culvert for water conveyance, the minimum pressure head of the pipe culvert should not be less than 2m. At the outlet of the pipeline, it can be appropriately reduced according to specific circumstances, but should not be less than 1m.

[0080] To meet the code requirements, under the normal operating conditions of the water pump, in order to prevent the occurrence of high - altitude vacuum liquid column separation in the water conveyance pipeline at high positions, the minimum pressure head of the pipeline should not be less than 2m between the pipeline mileage K50 + 460 and K51 + 170. Therefore, it is considered to add a regulating pond between the pipeline mileage K50 + 460 and K51 + 170 to separate the front and rear pipelines and disconnect from the water level at the end of the descending pipeline when entering the reservoir. Using hydraulics theory, the water level in the regulating pond is automatically set to stabilize the inlet and outlet pressure heads at the high position of the pipeline, which is not affected by the water conveyance length of the subsequent descending section of the pipeline and the water level at the end when entering the reservoir. Considering the influence of the water pump characteristics and the water - level automatic - control regulating pond, the normal - condition water conveyance capacity of the pumping station pressurized water conveyance system can ensure both the safe operation of the pipeline and improve the operation efficiency of the pumping station.

[0081] When setting up a regulating pond, the following issues need to be considered:

[0082] The selection of the location of the regulating pond;

[0083] The determination of the type and size of the regulating pond;

[0084] Whether to configure a flow regulating valve in the gravity - flow pipeline downstream of the regulating pond to regulate the flow rate in real - time.

[0085] The hydraulic design of the water - level automatic - control regulating pond is as follows:

[0086] The selection of the location of the regulating pond

[0087] The elevation of the water conveyance pipeline is the same and the highest between the pipeline mileage K50 + 460 and K51 + 170. Starting from the perspective of facilitating water hammer control, the regulating pond should be set at the front end of the high position, at the pipeline mileage K50 + 460. If it is set at other positions, such as the rear end, at the pipeline mileage K51 + 170, once the pumping station has an accident and loses power, a high - altitude vacuum may occur at the pipeline mileage K50 + 460, leading to a serious liquid column closing water hammer. Even if an air valve is set at the pipeline mileage K50 + 460, due to the end of air exhaust by the air valve, a serious liquid column closing water hammer may still occur. Therefore, it is more reasonable to set the regulating pond at the front end of the high position, at the pipeline mileage K50 + 460.

[0088] The determination of the type and size of the regulating pond

[0089] When a regulating pond is set at the highest point of the water conveyance pipeline after the pumping station discharges water, it should be ensured that the water level in the regulating pond is above 1m of the elevation of the top of the outlet pipe of the pipeline, that is, at the inlet end of the pipeline under normal operating conditions. To achieve this goal, two engineering measures can be taken:

[0090] An automatic water level regulating tank is adopted, and the structure of the regulating tank is shown in Figure 1 ;

[0091] A flow regulating valve is set at the end of the water conveyance pipeline behind the regulating tank.

[0092] For this project, the flow rate of the inlet pipe Q = 6.944 m 3 / s, the diameters of both the inlet and outlet pipes are 2.4 m, and the top elevations of the inlet and outlet pipes Z in = Z o = 54.2 m. The dimensional parameters Z y , S, B, Z w are determined by the following method.

[0093] Z y ≥ Z in +1 = 55.2 m;

[0094] The maximum water flow velocity V max in the outlet pipe = 1.54 m / s. Take V = 1.54 m / s and C = 0.55;

[0095] The minimum submergence depth S of the top of the outlet pipe = CVD 1 / = 1.32 m;

[0096] When the downstream pool water level H i ≥ Z o + S = 55.52 m, the inlet of the outlet pipe meets the requirement of not admitting air.

[0097] Considering the overflow weir width, the diameters of the inlet and outlet pipes, and certain installation and maintenance requirements on both sides, take B = 4.5 m and Z u = Z in +1 = 55.2 m;

[0098] When μ takes 0.36, the water level height of the upstream pool

[0099] When μ takes 0.5, the water level height of the upstream pool

[0100] H smax = 56.2 m;

[0101] The elevation of the top of the side wall of the pool Z w > H smax , considering a certain safety margin, take Z w = H smax +1 = 57.2 m.

[0102] A regulating valve is set at the end of the outlet pipe. By controlling the opening of the regulating valve in real time, the requirement of the minimum submergence depth of the top of the outlet pipe of the regulating tank is met, and the downstream pool water level H o≥Z o +S = 55.52 m.

[0103] This project was put into operation in 2023. The water level in the regulating pond is stable, the pressure of the water conveyance pipeline is normal, and the operation is good.

[0104] In summary, compared with the prior art, the present utility model has the following beneficial effects:

[0105] 1. In the embodiment of the present utility model, a regulating pond is arranged at the highest point of the water conveyance pipeline downstream of the pumping station. The pipelines before and after the regulating pond are isolated into an inlet pipe and an outlet pipe. An overflow weir is arranged in the regulating pond to divide the pond into an upstream pond and a downstream pond, so that the water level in the upstream pond is more than one meter higher than the top elevation of the inlet pipe, effectively avoiding the phenomenon of gas-liquid separation at the highest point of the water conveyance pipeline; when the pumping station has an accident and power failure, it can effectively prevent the dangerous water hammer pressure of the pumping station, and even if a gas-liquid two-phase flow occurs in the outlet pipe downstream of the regulating pond, it will not affect the normal and safe operation of the pumping station.

[0106] 2. In the embodiment of the present utility model, a flow regulating valve is arranged at the end of the outlet pipe. By controlling the opening of the flow regulating valve in real time, the occurrence of gas-liquid two-phase flow in the outlet pipe can be effectively avoided.

[0107] 3. In the embodiment of the present utility model, various parameters of the regulating pond are obtained through scientific calculation methods to ensure the safe and effective operation of the regulating pond.

[0108] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0109] The above embodiments are only used to illustrate the technical solutions of the present utility model, rather than to limit it; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present utility model.

Claims

1. A water level automatic control regulating tank for a water delivery project, characterized in that: The regulating pool is arranged at the highest point of the water delivery pipe downstream of the pump station, and the regulating pool comprises: a water pool (1); The upstream wall of the water pool (1) is provided with a water inlet (2), and the water inlet pipe is connected to the water pool (1) through the water inlet (2); the downstream wall of the water pool (1) is provided with a water outlet (3), and the water outlet pipe is connected to the water pool (1) through the water outlet (3); An overflow weir (4) perpendicular to the water flow direction is arranged in the middle of the water pool (1), and the overflow weir (4) divides the water pool into an upstream pool and a downstream pool.

2. The water level automatic regulating pond for water delivery project according to claim 1, characterized in that: The inlet pipe flow rate Q is known, and the inlet pipe top elevation and outlet pipe top elevation satisfy: WITH in =Z o ; Among them, Z in is the elevation of the water inlet pipe top; Z o is the top elevation of the outlet pipe.

3. The water level automatic regulating pond for water delivery project as claimed in claim 2, characterized in that: The overflow weir top elevation meets the following requirements: WITH y ≥Z in +1; Among them, Z y is the elevation of the overflow weir crest.

4. The water level automatic control regulating pond for water delivery project as claimed in claim 2, characterized in that: In order to avoid the appearance of vortex or suction funnel at the outlet (3), the minimum submergence depth of the outlet pipe top meets the following requirements: S=CVD 1 / 2 ; Where S is the minimum submergence depth of the outlet pipe top; C is a coefficient related to the geometric shape of the outlet. If the outlet flow is symmetrical, C is 0.55; if the boundary is complex and the lateral flow is 0.73; V is the water flow rate in the outlet pipe; D is the diameter of the outlet pipe; In order to ensure that the outlet pipe does not enter the air, the water level of the downstream pool must meet the following requirements: H o ≥Z o +S; Among them, H o is the water level of the downstream pool.

5. The water level automatic control regulating pond for water delivery project as claimed in claim 4, characterized in that: A flow regulating valve is provided at the end of the water outlet pipe, and the opening of the flow regulating valve is controlled in real time to maintain H o ≥Z o +S.

6. The water level automatic control regulating pond for water delivery project according to claim 1, characterized in that: When the overflow weir is in free outflow, the relationship between the inlet pipe flow and the water level of the upstream pool satisfies: Among them, B is the width of the overflow weir, that is, the net width of the pool; μ is the overflow flow coefficient, which is generally between 0.36 and 0.5; g is the acceleration due to gravity; H s is the water level of the upstream pool.

7. The water level automatic control regulating pond for water delivery project according to claim 6, characterized in that: μ is taken as 0.36 and 0.5 respectively, and the possible maximum water level H of the upstream pool is obtained. smax ; Pool side wall top elevation Z w >H smax .

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