Water delivery arrangement system for relieving low-temperature water drainage

Abstract

The invention discloses a water delivery arrangement system, particularly discloses a water delivery arrangement system for relieving low-temperature water drainage, and belongs to the technical field of design and construction of water conservancy and hydropower engineering structures. According to the water delivery arrangement system for relieving low-temperature water drainage, the excavation work amount is remarkably reduced, and it can be effectively ensured that water with the relatively high temperature and the relatively sufficient flow can be taken at any time. The water conveying arrangement system comprises a water storage reservoir which is arranged on a main stream river channel through a river blocking dam, and is characterized by further comprising a branch ditch river channel, a water conveying pipeline and a water inlet tower arranged at the input end of the water conveying pipeline, the branch ditch river channel is communicated with the water storage reservoir, and the water inlet tower is arranged on the branch ditch river channel; the river bottom elevation of the branch ditch river channel is higher than the riverbed elevation at the corresponding position of the main stream river channel and lower than the dead water level elevation of the reservoir; in the water taking process, the water inlet tower obtains stored water in the reservoir area of the water storage reservoir layer by layer from top to bottom through the branch ditch river channel.

Description

Technical Field

[0001] The present invention relates to a water conveyance layout system, and particularly to a water conveyance layout system for alleviating the discharge of low-temperature water, belonging to the technical field of design and construction of hydraulic and hydropower engineering structures. Background Art

[0002] 1. Glossary Explanation

[0003] 1) Normal pool level: The highest water level that a reservoir is allowed to store before the start of the water supply period under normal operating conditions to meet the requirements of water utilization such as power generation.

[0004] 2) Dead storage level: The lowest water level that a reservoir is allowed to drop to under the water utilization operation.

[0005] 3) Extreme dead storage level: The lowest water level that a reservoir is allowed to drop to during extremely dry water periods or under other special requirements.

[0006] 2. Water Temperature Stratification in Reservoirs

[0007] In natural rivers, the water temperature difference is relatively small, the turbulent mixing effect of the water body is strong, the free surface of the unit water body is large, and the temperature changes significantly with the air temperature. After a river is dammed to form a reservoir, the water temperature characteristics will change greatly. The reservoir usually shows a vertical water temperature stratification phenomenon. Generally, the water temperature of the upper layer of the reservoir is higher than that of the lower layer, and the water temperature at the bottom of the reservoir is the lowest.

[0008] 3. Hazards of Discharging Low-Temperature Water

[0009] When the reservoir water is discharged (through the water conveyance system) to the downstream river channel, if the water intake position is relatively low, low-temperature water in the lower layer or bottom layer of the reservoir may be taken, which will have a great impact on the water temperature distribution of the downstream natural river channel, resulting in a delay in the breeding period and a reduction in the yield of fish in the downstream water body (fish during the breeding period are very sensitive to water temperature), and a reduction in the yield of crops irrigated with the water from the downstream river channel.

[0010] 4. Existing Engineering Measures for Alleviating the Discharge of Low-Temperature Water and Main Problems

[0011] For hydraulic projects (such as hydropower stations), to ensure sufficient water intake and ensure that the water conveyance channel is in a pressurized flow state, the water intake of the water conveyance system needs to be set at a lower position (ensuring a certain submerged depth). Without setting other facilities, the water conveyance system usually can only take low-temperature water from the lower layer of the reservoir, thus causing a series of problems of discharging low-temperature water.

[0012] To solve the problem of discharging low-temperature water from a water temperature stratified reservoir, the commonly used scheme in current projects is to set a front retaining wall upstream of the water intake elevation of the intake tower, and to draw the relatively warmer upper layer water in the upstream reservoir through the restraint effect of the front retaining wall. The main problems of this scheme are as follows:

[0013] Problem 1: If the front retaining wall is set according to the general operating conditions (normal storage level ~ dead water level), in order to meet the requirements of the upper water body with a relatively high temperature for drinking water, the top elevation of the front retaining wall usually needs to be set at a relatively high position. When encountering some extreme operating conditions (such as power generation for supply during special dry seasons, water supply to the downstream, etc.), when the reservoir needs to operate between the dead water level and the extreme dead water level, due to the limitation of the front retaining wall, the water conveyance system may not be able to draw enough water. Even when the flow capacity of the front retaining wall meets the requirements, due to the insufficient water head at the top of the front retaining wall, the following may occur: ① The water level difference between the upstream and downstream of the front retaining wall is too large, affecting the stability of the retaining wall; ② The water flow velocity between the top of the front retaining wall and between the front retaining wall and the intake tower is too high, resulting in a disordered water flow pattern between the front retaining wall and the intake tower and even generating harmful vortices, affecting the safe operation of the water conveyance system and the generating units;

[0014] Problem 2: If the front retaining wall is set according to the special operating conditions (dead water level ~ extreme dead water level), in order to meet the requirement of drawing enough water at the extreme dead water level, the top elevation of the front retaining wall needs to be set at a relatively low position. Then, under the general operating conditions (normal storage level ~ dead water level), due to the too low top elevation of the front retaining wall, the water conveyance system will draw the lower layer of water in the reservoir with a relatively low temperature, and the effect of alleviating the discharge of cold water is relatively limited;

[0015] Problem 3: The height of the front retaining wall is relatively high, and it is necessary to first excavate the original terrain and then pour concrete. The amount of earth and rock excavation and the amount of concrete work are both large. Summary of the Invention

[0016] The technical problem to be solved by the present invention is to provide a water conveyance layout system for alleviating the discharge of cold water, which significantly reduces the amount of excavation work and can effectively ensure that relatively warm and relatively sufficient water can be drawn at any time.

[0017] The technical solution adopted to solve the above technical problem is: A water conveyance layout system for alleviating the discharge of cold water, including a storage reservoir, which is arranged on the main stream river channel through a barrage dam. It is characterized in that: the water conveyance layout system further includes a tributary river channel, a water conveyance pipeline, and an intake tower arranged at the input end of the water conveyance pipeline. The tributary river channel is connected to the storage reservoir, and the intake tower is arranged on the tributary river channel; the bottom elevation of the tributary river channel is higher than the riverbed elevation at the corresponding position of the main stream river channel and lower than the dead water level elevation of the storage reservoir; during the water intake process, the intake tower obtains the stored water in the reservoir area of the storage reservoir layer by layer from top to bottom through the tributary river channel.

[0018] Furthermore, the water conveyance layout system further includes a reserved rock sill, which is arranged on the tributary river channel in front of the intake tower. The top elevation of the reserved rock sill is higher than the intake bottom elevation of the intake tower and lower than the dead water level elevation of the storage reservoir.

[0019] The preferred embodiment of the above solution is that the projection of the reserved rock sill in its cross-section is in a zigzag shape including a rock platform section, a slope section, and a lower flat section. The rock platform section and the lower flat section are connected as a whole through the slope section. The elevation of the lower flat section is lower than the intake bottom elevation of the intake tower, and the top elevation of the rock platform section is higher than the intake bottom elevation of the intake tower and lower than the dead water level elevation of the reservoir.

[0020] Furthermore, the transverse width of the water passing surface of the rock platform section is greater than the width of the projection of the slope section in the horizontal plane, and the width of the projection of the slope section in the horizontal plane is greater than the width of the water passing surface of the lower flat section; the slope of the slope section is controlled between 35-55°.

[0021] The preferred embodiment of the above solution is that the reserved rock sill is composed of a rock excavation structure between the intake tower and the tributary channel.

[0022] Furthermore, the water conveyance arrangement system further includes a pre-tower vortex dissipation structure, which is arranged on the water inlet on the upstream side of the intake tower.

[0023] The preferred embodiment of the above solution is that the pre-tower vortex dissipation structure at least includes a water passing grille integrally formed on the upstream side wall surface of the intake tower.

[0024] Furthermore, the pre-tower vortex dissipation structure further includes at least one group of horizontal vortex dissipation frames, and each group of horizontal vortex dissipation frames is arranged in sequence in the vertical direction between the water passing grille and the upstream side wall surface of the intake tower.

[0025] The preferred embodiment of the above solution is that there are four groups of horizontally arranged vortex dissipation frames in sequence in the vertical direction. The upper two groups of horizontal vortex dissipation frames are composed of horizontal water passing holes, and the lower two groups of horizontal vortex dissipation frames are each composed of a group of vortex dissipation beams.

[0026] Furthermore, both the water passing grille and the vortex dissipation beam are structures cast with reinforced concrete.

[0027] The beneficial effects of the present invention are as follows: The technical solution provided in this application is based on the existing reservoir set on the main river channel through a barrage dam. By adding a tributary channel, a water conveyance pipeline, and an intake tower arranged at the input end of the water conveyance pipeline to form the water conveyance arrangement system of this application, the tributary channel is connected to the reservoir, and the intake tower is arranged on the tributary channel; then the bottom elevation of the tributary channel is higher than the riverbed elevation at the corresponding position of the main river channel and lower than the dead water level elevation of the reservoir; and during the water intake process, the intake tower obtains the stored water in the reservoir area of the reservoir layer by layer from top to bottom through the tributary channel. In this way, when taking water, since the upper layer of water is taken through the tributary channel in layers, it can effectively ensure that water with a relatively high temperature and relatively sufficient flow can be obtained at any time. At the same time, since there is no need to first excavate the river channel as in the prior art and then build a front water retaining wall in front of the water intake tower, but directly set the intake tower at the corresponding position of the tributary channel, the purpose of significantly reducing the engineering excavation volume can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 FIG. 1 is a schematic plan view of the water conveyance layout system for relieving the low-temperature water discharge of the present invention;

[0029] Figure 2 FIG. 2 is a schematic view of the structure of the water conveyance layout system for relieving the low-temperature water discharge of the present invention Figure 1 in the working state at the normal water level at the A-A cross-section position;

[0030] Figure 3 FIG. 3 is a schematic view of the structure of the water conveyance layout system for relieving the low-temperature water discharge of the present invention Figure 1 in the working state at the dead water level at the A-A cross-section position;

[0031] Figure 4 FIG. 4 is a schematic view of the structure of the water conveyance layout system for relieving the low-temperature water discharge of the present invention Figure 1 in the working state at the extreme dead water level at the A-A cross-section position.

[0032] In the figures, the markings are: storage reservoir 1, barrage dam 2, main river channel 3, tributary channel 4, water conveyance pipeline 5, intake tower 6, rock bench section 7, slope section 8, lower horizontal section 9, water passing grille 10, horizontal water passing hole 11, vortex elimination beam 12, reserved rock sill 13. DETAILED DESCRIPTION OF THE INVENTION

[0033] As Figure 1 、 Figure 2 、 Figure 3 and Figure 4Shown is a water conveyance layout system provided by the present invention for alleviating the discharge of low-temperature water, which significantly reduces the excavation work volume and can effectively ensure that water with a relatively high temperature and a relatively sufficient flow rate can be obtained at any time. The water conveyance layout system includes a reservoir 1, which is arranged on the main river channel 3 through a dam 2. The water conveyance layout system further includes a tributary channel 4, a water conveyance pipeline 5, and a water intake tower 6 arranged at the input end of the water conveyance pipeline 5. The tributary channel 4 is connected to the reservoir 1, and the water intake tower 6 is arranged on the tributary channel 4. The bottom elevation of the tributary channel 4 is higher than the riverbed elevation at the corresponding position of the main river channel 3 and lower than the dead water level elevation of the reservoir 1. During the water intake process, the water intake tower 6 obtains the stored water in the reservoir area of the reservoir layer by layer from top to bottom through the tributary channel 4. The technical solution provided by this application is based on an existing reservoir arranged on the main river channel through a dam. By adding a tributary channel, a water conveyance pipeline, and a water intake tower arranged at the input end of the water conveyance pipeline to form the water conveyance layout system of this application, the tributary channel is connected to the reservoir, and the water intake tower is arranged on the tributary channel. Then, the bottom elevation of the tributary channel is higher than the riverbed elevation at the corresponding position of the main river channel and lower than the dead water level elevation of the reservoir. And during the water intake process, the water intake tower obtains the stored water in the reservoir area of the reservoir layer by layer from top to bottom through the tributary channel. In this way, when taking water, since the upper layer of water is taken layer by layer through the tributary channel, it can effectively ensure that water with a relatively high temperature and a relatively sufficient flow rate can be obtained at any time. At the same time, since it is no longer necessary to first excavate the river channel as in the prior art and then build a front retaining wall in front of the water intake tower, but directly set the water intake tower at the corresponding position of the tributary channel, the purpose of significantly reducing the engineering excavation volume can be achieved.

[0034] Correspondingly, in combination with the existing technology, in order to obtain the upper-layer high-temperature water body to the greatest extent, the water conveyance layout system described in this application further includes a reserved rock sill 13, which is arranged on the tributary channel 4 in front of the water intake tower 6. The top elevation of the reserved rock sill 13 is higher than the intake bottom elevation of the water intake tower 6 and lower than the dead water level elevation of the reservoir 1. At this time, the projection of the reserved rock sill 13 in its cross-section is set to be a zigzag shape including a rock platform section 7, a slope section 8, and a lower flat section 9. The rock platform section 7 and the lower flat section 9 are connected as a whole through the slope section 8. The elevation of the lower flat section 9 is lower than the intake bottom elevation of the water intake tower 6, and the top elevation of the rock platform section 7 is higher than the intake bottom elevation of the water intake tower 6 and lower than the dead water level elevation of the reservoir 1. Further, in order to improve the flow pattern of the discharged water, the transverse width of the water passing surface of the rock platform section in this application is greater than the projected width of the slope section 8 in the horizontal plane, and the projected width of the slope section 8 in the horizontal plane is greater than the width of the water passing surface of the lower flat section. The slope of the slope section 8 is controlled between 35-55°. In order to reduce the investment cost, the reserved rock sill in this application is composed of the rock excavation structure between the water intake tower 6 and the tributary channel 4.

[0035] Further, in order to obtain a stable flow pattern in front of the water intake tower, in addition to making corresponding settings for the structure of the reserved rock sill, the present application is also provided with a vortex dissipation structure in front of the tower, and this vortex dissipation structure in front of the tower is arranged at the water inlet on the upstream side of the intake tower. At this time, the vortex dissipation structure in front of the tower at least includes a water passing grille 10 integrally formed on the upstream side wall surface of the intake tower. At this time, the preferred method is that the vortex dissipation structure in front of the tower further includes at least one group of horizontal vortex dissipation frames, and each group of horizontal vortex dissipation frames is arranged in sequence in the vertical direction between the water passing grille 10 and the upstream side wall surface of the intake tower. A more specific structure is that there are four groups of horizontally arranged vortex dissipation frames in sequence in the vertical direction. The upper two groups of horizontal vortex dissipation frames are composed of horizontal water passing holes 11, and the lower two groups of horizontal vortex dissipation frames are each composed of a group of vortex dissipation beams 12. Considering the convenience of investment and construction, the water passing grille 10 and the vortex dissipation beam 12 of the present application are both reinforced concrete casting structures.

[0036] In summary, the technical solution provided by the present application also has the following advantages:

[0037] 1. Under normal operating conditions (normal storage level ~ dead storage level) and special operating conditions (dead storage level ~ extreme dead storage level), the relatively warmer surface water in the reservoir can be taken. The specific description is as follows:

[0038] 1) The intake tower is arranged in a tributary on one bank of the river (close to the dam side) upstream of the dam. There is a certain distance between the intake tower and the confluence of the tributary and the river channel, and the bottom elevation of the tributary is higher than the bottom elevation of the river bed. When the reservoir is storing water and the intake tower is taking water, the water flow in the reservoir enters the water conveyance pipeline along the river, tributary, and intake tower. Due to the "narrow at the bottom and wide at the top" shape and the "inverted horn shape" effect of the tributary, the intake tower will be more likely to take the surface water in the reservoir;

[0039] 2) A reserved rock sill is set upstream of the intake tower, so the intake tower can only draw the surface water body in the reservoir that is higher than the top elevation of the rock platform section.

[0040] 2. Under special operating conditions (dead storage level ~ extreme dead storage level), enough water can be taken, and the water flow pattern in front of the intake tower is stable without harmful vortices. The specific description is as follows:

[0041] 1) The top elevation of the reserved rock sill is lower than the extreme dead storage level. Through hydraulic model tests to verify its flow capacity, it can meet the requirement of taking enough water at the extreme dead storage level;

[0042] 2) The reserved rock sill adopts the broad-crested weir type, and the rock platform section has a considerable width, so there is sufficient adjustment space for the water flow before it enters the intake tower, avoiding the problems of large upstream and downstream water level differences and disordered flow patterns in the conventional front retaining wall scheme, and ensuring the stability of the water flow pattern in front of the intake tower;

[0043] 3) The reserved rock sill structure is thick, which can avoid the structural stability problems that may be caused by the large water level difference between the upstream and downstream in the conventional front retaining wall scheme.

[0044] 4) A vortex-eliminating beam is arranged at the upstream end of the intake tower. Even under the condition of the extreme dead water level and a small submerged depth of the intake tower, the harmful vortices in the water body in front of the intake tower can be eliminated, ensuring the safety of the water conveyance system and the generator set.

[0045] 3. The structure is simple, the engineering quantity is saved, and it is environmentally friendly. The specific description is as follows:

[0046] 1) Compared with the conventional front retaining wall scheme, the reserved rock sill scheme of the present invention forms a front retaining wall by excavation using natural rock mass, with a simple structure and convenient operation and maintenance.

[0047] 2) Compared with the conventional front retaining wall scheme, the reserved rock sill scheme of the present invention reduces the excavation volume and no longer requires a concrete structure. While significantly saving the engineering quantity, the adverse environmental impacts caused by excavation waste, aggregate mining and concrete processing will also be reduced.

[0048] The technical solution of the present application will be further described below through specific embodiments:

[0049] Embodiment 1

[0050] The technical problem to be solved by the present application is to provide an engineering measure for alleviating the discharge of low-temperature water, which is set by using natural topographic conditions, can not only always take the upper layer of water with a higher temperature under normal operating conditions (normal storage water level - dead water level), but also take enough water volume under special operating conditions (dead water level - extreme dead water level), with stable water flow pattern in front of the intake tower, no harmful vortices, simple structure and relatively less engineering quantity, and is particularly suitable for high dam projects with large variable ranges of reservoir operating water levels.

[0051] The technical solution adopted for solving the technical problem of the present application is as follows:

[0052] 1. The engineering measure for alleviating the discharge of low-temperature water is composed of an intake tower structure and a reserved rock sill arranged upstream of the intake tower.

[0053] 2. The intake tower is arranged as follows:

[0054] 1) The intake tower is arranged in a tributary of one bank of the river upstream of the dam (close to the dam side), and a certain distance is maintained between the intake tower and the confluence of the river tributary. The bottom elevation of the tributary is higher than the bottom elevation of the river bed.

[0055] 2) The upstream of the intake tower is a reserved rock sill, and a lower horizontal section is arranged between the intake tower and the reserved rock sill. The elevation of the lower horizontal section is lower than the intake bottom elevation.

[0056] 3) A vortex dissipation beam is provided at the upstream end of the intake tower, and the vortex dissipation beam is arranged below the extreme dead water level.

[0057] 3. The reserved rock sill is arranged as follows:

[0058] 1) The reserved rock sill is formed by excavating the rock mass between the intake tower and the branch ditch, and includes two parts: a rock platform section and a slope section;

[0059] 2) The top elevation of the rock platform section is lower than the extreme dead water level, and it is necessary to meet the requirements of water intake and flow pattern stability of the intake tower at the extreme dead water level. The specific elevation can be verified through a hydraulic model test;

[0060] 3) The rock platform section has a sufficient width to form a broad-crested weir flow pattern during operation at the extreme dead water level;

[0061] 4) The slope section is used to connect the rock platform section and the lower horizontal section, and its slope ratio is set to meet the requirements of stable water intake flow pattern of the intake tower, which can be determined through a hydraulic model test.

Claims

1. A water conveyance layout system for alleviating the low-temperature water discharge, comprising a storage reservoir (1), the storage reservoir (1) is arranged on the main stream river channel (3) through a river-blocking dam (2), and is characterized in that: The described water conveyance layout system further includes a branch ditch river course (4), a water conveyance pipeline (5), and an intake tower (6) arranged at the input end of the water conveyance pipeline (5). The branch ditch river course (4) is connected to the storage reservoir (1), and the intake tower (6) is arranged on the branch ditch river course (4); the bottom elevation of the branch ditch river course (4) is higher than the riverbed elevation at the corresponding position of the main stream river course (3) and lower than the dead water level elevation of the storage reservoir (1); during the water intake process, the intake tower (6) obtains the stored water in the storage reservoir area layer by layer from top to bottom through the branch ditch river course (4).

2. The water conveyance arrangement system for alleviating low-temperature water discharge according to claim 1, wherein: The described water conveyance layout system further includes a reserved rock sill (13), and the reserved rock sill (13) is arranged on the branch ditch river course (4) in front of the intake tower (6). The top elevation of the reserved rock sill (13) is higher than the intake bottom elevation of the intake tower (6) and lower than the dead water level elevation of the storage reservoir (1).

3. The water conveyance arrangement system for alleviating low-temperature water discharge according to claim 2, characterized in that: The projection of the reserved rock sill (13) in its cross-section is in a zigzag shape including a rock platform section (7), a slope section (8), and a lower flat section (9). The rock platform section (7) and the lower flat section (9) are connected as a whole through the slope section (8). The elevation of the lower flat section (9) is lower than the intake bottom elevation of the intake tower (6), and the top elevation of the rock platform section (7) is higher than the intake bottom elevation of the intake tower (6) and lower than the dead water level elevation of the storage reservoir (1).

4. The water conveyance arrangement system for alleviating low-temperature water discharge according to claim 3, characterized in that: The transverse width of the water passing surface of the rock platform section is greater than the width of the projection of the slope section (8) in the horizontal plane, and the width of the projection of the slope section (8) in the horizontal plane is greater than the width of the water passing surface of the lower flat section; the slope of the slope section (8) is controlled between 35 - 55°.

5. The water conveyance arrangement system for alleviating low-temperature water discharging according to claim 2, 3 or 4, characterized in that: The reserved rock sill is composed of a rock mass excavation structure between the intake tower (6) and the branch ditch river course (4).

6. The water conveyance arrangement system for alleviating low-temperature water discharge according to claim 5, wherein: The described water conveyance layout system further includes a vortex dissipation structure in front of the tower, and the vortex dissipation structure in front of the tower is arranged at the water inlet on the upstream side of the intake tower.

7. The water conveyance arrangement system for alleviating low-temperature water discharge according to claim 6, characterized in that: The vortex dissipation structure in front of the tower at least includes a water passing grille (10) integrally formed on the upstream side wall surface of the intake tower.

8. The water conveyance arrangement system for alleviating low-temperature water discharge according to claim 7, characterized in that: The vortex dissipation structure in front of the tower further includes at least one group of horizontal vortex dissipation frames, and each group of horizontal vortex dissipation frames is arranged sequentially in the vertical direction between the water passing grille (10) and the upstream side wall surface of the intake tower.

9. The water conveyance arrangement system for alleviating low-temperature water outflow according to claim 8, characterized in that: There are four groups of horizontally arranged vortex dissipation frames in the vertical direction. The upper two groups of horizontal vortex dissipation frames are composed of horizontal water passing holes (11), and the lower two groups of horizontal vortex dissipation frames are each composed of a group of vortex dissipation beams (12).

10. The water conveyance arrangement system for alleviating low-temperature water release according to claim 9, characterized in that: Both the water passing grille (10) and the vortex dissipation beam (12) are reinforced concrete casting structures.

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