Water-sand separation device, water diversion power generation system and water-sand separation method

Abstract

The application provides a water-sand separation device, a water diversion power generation system and a water-sand separation method, and relates to the technical field of hydraulic engineering. The water-sand separation device comprises a main tunnel, a connecting structure, a sand discharge branch tunnel, an outlet gate and a power generation branch tunnel. The main tunnel is used for connecting a muddy water river. The connecting structure has a first interface, a second interface and a vertical shaft which are connected to each other. The first interface is connected to the main tunnel. One end of the sand discharge branch tunnel is connected to the second interface. The other end of the sand discharge branch tunnel is used for connecting a downstream river channel. The extension direction of the sand discharge branch tunnel is parallel to the extension direction of the main tunnel. The outlet gate is arranged on the sand discharge branch tunnel and is used for controlling the conduction or closing of the sand discharge branch tunnel between the second interface and the downstream river channel. One end of the power generation branch tunnel is connected to the vertical shaft. The other end of the power generation branch tunnel is used for connecting a water turbine generator set. The application can ensure the power generation efficiency and service life of the water turbine generator set.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, and more specifically, to a water-sediment separation device, a water diversion and power generation system, and a water-sediment separation method. Background Technology

[0002] A hydroelectric power generation system is an engineering system that converts the energy of river water into electrical energy, with hydroelectric power generation as its core objective.

[0003] The water diversion and power generation system built on the muddy river includes a main tunnel and a turbine generator set. The main tunnel is mainly used to transport the muddy river water containing silt to the turbine generator set for power generation.

[0004] However, due to the high silt content in the muddy river, the silt entering the turbine generator set can cause wear and tear, thus affecting the power generation efficiency and service life of the turbine generator set. Summary of the Invention

[0005] The problem addressed by this invention is how to ensure the power generation efficiency and service life of a hydro-generator unit.

[0006] To address the above problems, this invention provides a water-sediment separation device, a water diversion and power generation system, and a water-sediment separation method.

[0007] In a first aspect, the present invention provides a water-sand separation device, comprising: The main tunnel is used to connect to the muddy river. A connecting structure having a first interface, a second interface, and a shaft that are interconnected, wherein the first interface is connected to the main tunnel; A sand-drainage branch tunnel, one end of which is connected to the second interface, and the other end of which is used to connect to the downstream river channel, and the extension direction of the sand-drainage branch tunnel is parallel to the extension direction of the main tunnel. An outlet gate is provided in the sand discharge branch tunnel and is used to control the opening or closing of the sand discharge branch tunnel between the second interface and the downstream river channel. A power generation branch tunnel, one end of which is connected to the vertical shaft, and the other end of which is used to connect to a hydro-generator unit.

[0008] Optionally, the connecting structure further includes a settling cavity, wherein the connection between the first interface, the second interface, and the shaft is the settling cavity; the radial cross-sections of the first interface, the settling cavity, and the shaft first expand and then contract.

[0009] Optionally, the maximum radial cross-sectional area of ​​the settlement cavity is three times the radial cross-sectional area of ​​the main tunnel.

[0010] Optionally, the connection between the shaft and the first interface has a first arc structure.

[0011] Optionally, the axis of the vertical shaft is set at an angle to the axis of the power generation branch tunnel.

[0012] Optionally, the connection between the vertical shaft and the power generation branch tunnel has a second arc structure.

[0013] Optionally, the minimum height difference between the end axis of the power generation branch tunnel near the shaft and the axis of the main tunnel is greater than or equal to three times the diameter of the main tunnel.

[0014] Optionally, the diameters of the sand-drainage branch tunnel and the power generation branch tunnel are less than or equal to the diameter of the main tunnel.

[0015] Secondly, the present invention provides a water diversion power generation system, including a hydro-turbine generator set and a water-sediment separation device as described above.

[0016] Thirdly, the present invention provides a water-sediment separation method based on the water-sediment separation device described above, comprising the following steps: The water carrying silt in the muddy river is transported through the main tunnel to the connecting structure. The inertia of the silt causes the coarse particles of silt in the water to be flushed into the sand discharge branch tunnel connected to the connecting structure, thus achieving the first separation of the coarse particles of silt from the water. After the first separation, the sand-laden water flow turns at the second interface of the connecting structure and flows upward along the vertical shaft. Under the action of gravity, the medium-sized particles in the sand-laden water flow settle and are washed into the sand discharge branch tunnel, thus realizing the second separation of medium-sized particles in the sediment from the water. After being separated twice, the low-sediment-laden water flows through the vertical shaft and is then transported to the turbine generator unit via the power generation branch tunnel.

[0017] The beneficial effects of the water-sediment separation device, water diversion and power generation system, and water-sediment separation method of the present invention are as follows: The main tunnel diverts and guides the high-sediment-laden water flow from the muddy river to the first interface of the connecting structure. Since the first and second interfaces of the connecting structure are connected to the main tunnel and the sediment-discharging branch tunnel respectively, and the extension direction of the sediment-discharging branch tunnel is parallel to the extension direction of the main tunnel, the denser, high-sediment-laden water flow in the main tunnel, due to inertia, tends to maintain its original direction and more easily enters the sediment-discharging branch tunnel, which is aligned with the extension direction of the main tunnel. Consequently, large particles in the high-sediment-laden water flow remain in the sediment-discharging branch tunnel due to their own gravity, achieving the first separation of large particles from the water. After this first separation, the sediment-laden water flow flows from the connecting... The second interface of the structure turns and flows upward along the shaft. Utilizing gravity, medium-sized particles in the sediment-laden water settle and silt down. They are then flushed into the desilting branch tunnel by the water flow from the main tunnel, achieving a second separation of medium-sized particles from the water. Finally, the low-sediment-laden water, after two separations, passes through the shaft and is transported to the hydro-turbine generator unit for power generation via the power generation branch tunnel. This effectively reduces the amount of sediment entering the hydro-turbine generator unit, thereby reducing wear and tear on the generator unit, ensuring its power generation efficiency and service life, and also reducing operation and maintenance workload and operating costs. Attached Figure Description

[0018] Figure 1 This is one of the structural schematic diagrams of the water-sand separation device in the embodiments of the present invention; Figure 2 This is a second schematic diagram of the water-sand separation device in an embodiment of the present invention; Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure along section line AA; Figure 4 for Figure 2 A schematic diagram of the cross-sectional structure along section line BB; Figure 5 for Figure 1 A schematic diagram of the cross-sectional structure along the central section line CC; Figure 6 for Figure 3 A schematic diagram of the cross-sectional structure along the central section line DD; Figure 7 This is the third schematic diagram of the water-sand separation device in the embodiments of the present invention.

[0019] Explanation of reference numerals in the attached figures: 1-Main tunnel; 2-Connecting structure; 21-First interface; 22-Second interface; 23-Vertical shaft; 24-First circular arc structure; 25-Second circular arc structure; 26-Settling chamber; 3-Sand discharge branch tunnel; 4-Outlet gate; 5-Power generation branch tunnel; 6-Hydropower generator set; 7-Downstream river channel. Detailed Implementation

[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0021] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0022] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0023] like Figure 1 , Figure 2 and Figure 7 As shown, an embodiment of the present invention provides a water-sand separation device, comprising: Main tunnel 1, which is used to connect to the muddy river; The connecting structure 2 has a first interface 21, a second interface 22 and a vertical shaft 23 that are interconnected, and the first interface 21 is connected to the main tunnel 1. The sand-drainage branch tunnel 3 has one end connected to the second interface 22 and the other end connected to the downstream river channel 7. The extension direction of the sand-drainage branch tunnel 3 is parallel to the extension direction of the main tunnel 1. An outlet gate 4 is provided in the sand discharge branch tunnel 3 and is used to control the opening or closing of the sand discharge branch tunnel 3 between the second interface 22 and the downstream river channel 7. The power generation branch tunnel 5 has one end connected to the vertical shaft 23 and the other end connected to the water turbine generator set 6.

[0024] Specifically, the shape of the connecting structure 2 can be similar to that of a conventional tee connector; the connecting structure 2 has three interfaces, namely the first interface 21, the second interface 22 and the shaft 23. The first interface 21, the second interface 22 and the shaft 23 can be basically T-shaped. The first interface 21 can face the main tunnel 1, the second interface 22 can face the sand discharge branch tunnel 3, the bottom end of the shaft 23 can face the connection of the first interface 21 and the second interface 22, and the top end of the shaft 23 can extend upward relative to the main tunnel 1 and connect with the power generation branch tunnel 5.

[0025] The outlet gate 4 is located near the downstream channel 7 of the desilting tunnel 3. This not only increases the amount of sediment temporarily stored in the desilting tunnel 3, but also prevents the water flow in the downstream channel 7 from flowing back into the end of the desilting tunnel 3 away from the second interface 22. The outlet gate 4 can be controlled by a hoist to open and close the desilting tunnel 3 by raising, lowering or rotating the outlet gate 4.

[0026] Figure 1 The dotted circle resembling a cloud can refer to connection structure 2.

[0027] The parallel extension direction of the sand-drainage branch tunnel 3 to the extension direction of the main tunnel 1 means that the extension direction of the sand-drainage branch tunnel 3 is consistent with the extension direction of the main tunnel 1, or that there is a small gap between them.

[0028] In this embodiment, the main tunnel 1 can divert and guide the high-sediment-laden water flow from the muddy river to the first interface 21 of the connecting structure. Since the first interface 21 and the second interface 22 of the connecting structure are respectively connected to the main tunnel 1 and the sediment discharge branch tunnel 3, and the extension direction of the sediment discharge branch tunnel 3 is consistent with or parallel to the extension direction of the main tunnel 1, the high-sediment-laden water flow with a higher density in the main tunnel 1 tends to maintain its original direction due to inertia and is more likely to enter the sediment discharge branch tunnel 3, which is consistent with the extension direction of the main tunnel 1. Therefore, the coarse particles in the high-sediment-laden water flow remain in the sediment discharge branch tunnel 3 due to their own gravity, achieving the first separation of coarse particles from water in the sediment. Under the action of water pressure, the sediment-laden water flow after the first separation enters from the first interface 21 of the connecting structure 2 and... The second interface 22 turns upward and reaches the vertical shaft 23. During the flow towards the vertical shaft, the water velocity decreases sharply, and the sand-carrying capacity is greatly reduced. At the same time, under the action of gravity, the medium-sized particles in the sand-laden water settle and silt down, and are flushed into the sand-discharging branch tunnel 3 by the water flow from the main tunnel 1, realizing the second separation of medium-sized particles in the sediment from the water. If the outlet gate 4 is open at this time, the coarse and medium-sized sediment particles separated by the above two separations are discharged into the downstream river channel 7 with the water flow. If the outlet gate 4 is closed at this time, the coarse and medium-sized sediment particles separated by the above two separations are temporarily stored in the sand-discharging branch tunnel 3 on the upstream side of the outlet gate 4, and are discharged into the downstream river channel 7 with the water flow after the outlet gate 4 is reopened.

[0029] Finally, the low-sediment-laden water flow after two separations passes through the vertical shaft 23 and is transported to the turbine generator unit 6 through the power generation branch tunnel 5 for power generation. This effectively reduces the amount of sediment entering the turbine generator unit 6, thereby reducing wear on the turbine generator unit 6, ensuring the power generation efficiency and service life of the turbine generator unit 6, or reducing the workload and operating costs of operation and maintenance.

[0030] Optionally, combined Figures 2 to 6 As shown, the connecting structure 2 also has a settling cavity 26, and the connection part of the first interface 21, the second interface 22 and the vertical shaft 23 is the settling cavity 26; the radial cross sections of the first interface 21, the settling cavity 26 and the vertical shaft 23 first expand and then shrink.

[0031] Specifically, the radial cross-section from the first interface 21 to the vertical shaft 23 first expands and then shrinks. This can be understood as the intersection of the first interface 21, the second interface 22, and the vertical shaft 23 being defined as the settling cavity 26. In this case, the radial cross-section from the first interface 21 to the settling cavity 26 first expands (in other words, the radial cross-section of the settling cavity 26 is larger than the radial cross-section of the first interface 21), and then the radial cross-section from the settling cavity 26 to the vertical shaft 23 shrinks (in other words, the radial cross-section of the vertical shaft 23 is smaller than the radial cross-section of the settling cavity 26). Therefore, the radial cross-section at the settling cavity 26 is the largest part in the entire connected structure 2.

[0032] Figure 4 The dotted circle resembling a cloud can refer to connection structure 2.

[0033] In this optional embodiment, since the radial cross-sections of the first interface 21, the settling chamber 26, and the vertical shaft 23 first expand and then contract, in other words, the entire path from the first interface 21 to the vertical shaft 23 can be divided into an expanding section and a contracting section in sequence, the expanding section utilizes a sharp drop in flow velocity, causing the drag force of the water flow on particles of medium or larger diameter (diameter greater than 8mm) to be lower than their own weight. These particles settle and silt under the action of gravity, causing a large amount of silt to separate from the main water flow before entering the vertical shaft 23, and then be flushed into the sand discharge branch tunnel 3 for temporary storage, achieving a second separation; the shape of the expanding section can also guide the water flow to transition smoothly, reduce eddies and secondary flows caused by sudden changes, stabilize the water flow to the vertical shaft 23, and make it difficult for the settled silt to be re-entrained, thus consolidating the separation effect; the contracting section ensures that the separated clean water can enter the vertical shaft 23 and the subsequent power generation branch tunnel 5 with sufficient flow velocity and kinetic energy, avoiding a decrease in water conveyance capacity or silt accumulation in the power generation branch tunnel 5 due to excessively low flow velocity.

[0034] Optionally, combined Figure 3 , Figure 5 and Figure 6As shown, the maximum radial cross-sectional area of ​​the settling cavity 26 is three times the radial cross-sectional area of ​​the main tunnel 1.

[0035] Specifically, if the radius of the main tunnel 1 is R, then the diameter of the main tunnel 1 is 2R, and the diameter of the first interface 21 is 2R (see...). Figure 6 The radial cross-section of the settling cavity 26 can be elliptical, with a major semi-axis dimension of 3R and a minor semi-axis dimension of R. Therefore, the maximum radial cross-sectional area of ​​the settling cavity 26 is 3πR. 2 .

[0036] The radial cross-section of the main tunnel 1 can be circular, and the radial cross-sectional area of ​​the main tunnel 1 is πR. 2 Therefore, the maximum radial cross-section of the settling cavity 26 is three times the radial cross-section of the main tunnel 1.

[0037] In this optional embodiment, the maximum radial cross-section of the settling chamber 26 is three times the radial cross-section of the main tunnel 1. As a result, the water flowing from the first interface 21 or the second interface 22 to the connection between the first interface 21 and the shaft 23 (settling chamber 26) suddenly increases in cross-sectional area. The average flow velocity of the water in the settling chamber 26 will drop to 1 / 3 or even lower than the flow velocity from the main tunnel 1. This results in a significant reduction in the drag force of the water flow on particles of medium or larger diameter (diameter greater than 8 mm) and it is lower than their own weight. Under the action of gravity, these particles obtain sufficient time and space to settle and silt in the expanded chamber, and the separation efficiency is improved by orders of magnitude.

[0038] In related technologies, there may be sharp corners at the connection between the main tunnel 1 and the power generation branch tunnel 5. When the high-speed water flow of the main tunnel 1 passes through a sharp corner, due to fluid inertia, its streamlines cannot closely adhere to the side wall of the power generation branch tunnel 5, resulting in flow separation and the formation of a vortex zone with large energy dissipation and chaotic flow behind the corner.

[0039] Optionally, combined Figure 4 As shown, the connection between the vertical shaft 23 and the first interface 21 has a first arc structure 24.

[0040] Specifically, the first arc structure 24 may be located outside the connection between the vertical shaft 23 and the first interface 21.

[0041] In this optional embodiment, with the turbine generator set running, under the action of water pressure, the water flow in the main tunnel 1 flows upward after passing through the first interface 21 and the second interface 22, first entering the settling chamber 26, and then continuing to flow upward along the shaft 23. The first arc structure 24 effectively increases the volume of the settling chamber 26, providing a smooth radius of curvature to guide the water flow streamline to change direction smoothly and continuously. Furthermore, the maximum radial cross-section of the settling chamber 26 is three times the radial cross-section of the main tunnel 1. Therefore, the settling chamber 26, with its larger radial cross-section, can achieve more stable and effective gravity settling of sediment in this area while reducing the water flow velocity between the main tunnel 1 and the settling chamber 26, promoting sediment settling rather than being filled with ineffective eddies.

[0042] Furthermore, the first arc structure 24 has a smooth turning characteristic, which not only eliminates strong vortices and protects the separated silt from being carried away again, thus consolidating the separation results, but also allows the relatively clear water in the upper layer after settling to be guided into the vertical shaft 23 in a more concentrated and orderly manner, reducing the mixing of clear water with the sand-containing water flow at the bottom and improving the "clean water extraction" efficiency.

[0043] The smooth transition of the first circular arc structure 24 reduces energy loss caused by flow separation and vortices. Although its primary purpose is not energy saving, it objectively improves the hydraulic efficiency of the system. Strong vortices and flow separation in related technologies can cause local pressure pulsations, which, over the long term, may lead to structural cavitation or induce vibration. The circular arc design of the first circular arc structure 24 improves the stress state and is beneficial for the long-term safe operation of the connected structure.

[0044] Optionally, combined Figure 1 As shown, the axis of the vertical shaft 23 is set at an angle to the axis of the power generation branch tunnel 5.

[0045] Specifically, since both the vertical shaft 23 and the power generation branch tunnel 5 can be cylindrical structures, both the vertical shaft 23 and the power generation branch tunnel 5 have their own axes. The axis of the vertical shaft 23 and the axis of the power generation branch tunnel 5 can be set at an obtuse angle.

[0046] In this optional embodiment, the axis of the vertical shaft 23 is set at an angle (e.g., an obtuse angle) to the axis of the power generation branch tunnel 5. The change in flow direction is used to perform secondary screening of the residual fine particles of silt in the low-sediment-content water flow, further purifying the water for power generation. In addition, the angle between the top of the vertical shaft 23 and the end of the power generation branch tunnel 5 changes the direction of the low-sediment-content water flow, so that only the clearer water flow at the top is easily "guided" in, further effectively isolating the bottom silt, which is equivalent to achieving a third separation of silt.

[0047] Optionally, combined Figure 4 and Figure 7As shown, the connection between the vertical shaft 23 and the power generation branch tunnel 5 has a second circular arc structure 25.

[0048] Specifically, the outer and inner peripheral walls of the connection between the vertical shaft 23 and the power generation branch tunnel 5 both have a second circular arc structure 25.

[0049] In this optional embodiment, the connection between the vertical shaft 23 and the power generation branch tunnel 5 has a second arc structure 25, which allows the low-sediment-laden water flow that has already been separated in the vertical shaft 23 to be introduced into the power generation branch tunnel 5 without loss and with excellent flow characteristics. This avoids secondary mixing of the low-sediment-laden water flow with the residual sediment that may float to the surface in the settling chamber 26 due to poor flow characteristics in the final step. The second arc structure 25 can be equivalent to the inlet of the power generation branch tunnel 5, so that the smooth inlet of the power generation branch tunnel 5 means that the water flow velocity distribution in the power generation branch tunnel 5 is more uniform and the pressure pulsation is smaller. This provides extremely superior water intake conditions for the downstream hydro-turbine generator unit 6, which is an important prerequisite for the hydro-turbine generator unit 6 to achieve efficient, stable and low-vibration operation. Furthermore, the arc transition between the vertical shaft 23 and the power generation branch tunnel 5 (second arc structure 25) significantly reduces the local resistance coefficient and head loss, so that the mechanical energy (head) contained in the water flow can be delivered to the hydro-turbine generator unit 6 with the highest efficiency after all separation processes are completed, directly contributing to the power generation benefits.

[0050] The second circular arc structure 25 ensures that the water flow ultimately reaching the turbine generator unit 6 is not only extremely low in sediment but also exhibits excellent flow characteristics. This dual protection minimizes the risk of equipment wear and optimizes operating conditions.

[0051] Optionally, combined Figure 4 As shown, the minimum height difference between the end axis of the power generation branch tunnel 5 near the shaft 23 and the axis of the main tunnel 1 is greater than or equal to three times the diameter of the main tunnel 1.

[0052] Specifically, the height difference between the end axis of the power generation branch tunnel 5 near the vertical shaft 23 and the axis of the main tunnel 1 can be used... Figure 4 The letter L in the text represents...

[0053] For example, if the elevation difference L between the location of the power generation branch tunnel 5 near the axis of the vertical shaft 23 and the axis of the main tunnel 1 is 6R or more, and the diameter of the main tunnel 1 is 2R, then the elevation difference L is three times or more the diameter of the main tunnel 1. Here, R can be the radius of the main tunnel 1.

[0054] In this optional embodiment, the minimum height difference between the end axis of the power generation branch tunnel 5 near the shaft 23 and the axis of the main tunnel 1 is greater than or equal to three times the diameter of the main tunnel 1. In other words, the water inlet of the power generation branch tunnel 5 is located at a position much higher than the main tunnel 1 (the source of turbid water), ensuring that the water intake of the main tunnel 1 is located in the upper clear water zone after sedimentation and separation by the shaft 23. The axial height difference greater than or equal to three times the diameter of the main tunnel 1 provides sufficient and reliable vertical space for water and sand to stratify according to density within the shaft 23 and the connecting structure 2, allowing the water intake to always "draw" the cleanest surface water, physically isolating the bottom of the power generation branch tunnel 5 from any sediment-laden water flow that may accumulate or flow. In addition, and more importantly, it ensures that there is sufficient thickness of the surrounding rock mass between the two tunnels, ensuring the stability of the rock mass structure of the surrounding rock cavern group at this intersection.

[0055] When the outlet gate 4 of the sand-discharging branch tunnel 3 is opened for active sand discharge, the flow path from the main tunnel 1 to the sand-discharging branch tunnel 3 is formed, and the local hydrodynamic conditions change. The sufficiently large elevation difference (≥3 times the diameter of the main tunnel 1) provides a huge safety margin for the intake of the power generation branch tunnel 5, which can effectively prevent the local low pressure or water flow disturbance that may be generated during sand discharge from affecting the water intake, avoid the intake of sediment or air, and ensure that the water quality for power generation remains stable and clean under sand discharge conditions.

[0056] Optionally, combined Figure 1 As shown, the diameters of the sand-drainage branch tunnel 3 and the power generation branch tunnel 5 are less than or equal to the diameter of the main tunnel 1.

[0057] Specifically, the diameters of the power generation branch tunnel 5 and the sand discharge branch tunnel 3 are generally slightly smaller than or equal to the diameter of the main tunnel 1, and are determined based on factors such as the flow rate of the hydro-generator unit 6, the economic flow velocity of the power generation branch tunnel, the erosion and wear resistance design requirements of the sand discharge branch tunnel 3, and its outlet layout.

[0058] In this optional embodiment, the desilting branch tunnel 3 has a small diameter (at a given desilting flow rate), ensuring that the desilting water flow has sufficient velocity and kinetic energy to continuously and smoothly flush and transport the separated sediment to the downstream river channel 7. This avoids siltation in the desilting branch tunnel 3 itself and ensures the unimpeded "desilting function" of the water-separation device. Simultaneously, it avoids excessive abrasive damage to the lining structure of the desilting branch tunnel 3 caused by the high-speed water flow, meeting the erosion and wear-resistant design requirements of the desilting branch tunnel 3 and ensuring the safety of the lining structure.

[0059] Based on the specific flow rate required by the hydro-generator unit 6 and the economical flow velocity of the power generation branch tunnel 5, the diameter of the power generation branch tunnel 5 is selected to be slightly smaller than that of the main tunnel 1. This can control the engineering construction costs (excavation, reinforced concrete lining, steel, etc.) while keeping the water flow energy loss within a reasonable range and preventing the deposition of fine sand in the power generation branch tunnel 5 due to excessively low flow velocity.

[0060] The present invention provides a water diversion power generation system, including a hydro-turbine generator set 6 and a water-sediment separation device as described in the above embodiment.

[0061] Specifically, the end of the power generation branch tunnel 5 in the water-sand separation device that is far from the vertical shaft 23 is connected to the water turbine generator set 6.

[0062] The beneficial effects of the water diversion power generation system in this embodiment compared to the prior art are the same as those of the water and sediment separation device described above, and will not be repeated here.

[0063] The present invention provides a water-sediment separation method based on the water-sediment separation device described in the above embodiments, comprising the following steps: S1. The water carrying silt in the muddy river is transported through the main tunnel 1 to the connecting structure 2. Utilizing the inertia of the silt, the coarse particles of silt in the water are flushed into the sand discharge branch tunnel 3 connected to the connecting structure 2, thus achieving the first separation of the coarse particles of silt from the water.

[0064] When the bedload sediment in the main tunnel 1 reaches the connecting structure 2 at a medium to high speed (flow velocity 5.0 to 7.0 m / s), the coarse particles (usually larger than 50 mm in diameter) have large mass and inertia, and their trajectory is difficult to change. Under the action of inertial force, they are pressed against the bottom of the main tunnel 1 and the connecting structure 2 and directly rush into the sand discharge branch tunnel 3, achieving the first separation.

[0065] S2. Under the action of water pressure, the sand-laden water flow after the first separation turns from the second interface 22 of the connecting structure 2 and flows upward along the vertical shaft 23. Upon reaching the vertical shaft 23, the water flow passes through the settling chamber 26, the cross-sectional area of ​​the flow increases, the water flow velocity decreases sharply, and the sand-carrying capacity is greatly reduced. At the same time, gravity is used to cause the medium-sized particles in the sand-laden water flow to settle and silt down, and be flushed into the sand discharge branch tunnel 3 by the water flow, thus realizing the second separation of medium-sized particles in the sediment from the water.

[0066] The sediment-laden water, after inertial screening, enters the settling chamber 26 through the first interface 21 under the pressure of the main tunnel 1, then turns upwards to the vertical shaft 23. Calculations using the General Drag Force Formula show that the flow cross-section (maximum radial section) of the water in the settling chamber 26 expands dramatically to approximately three times the radial section of the main tunnel 1, causing a sudden drop in flow velocity. This results in the drag force exerted on medium-sized and larger particles (diameter greater than 8 mm) being lower than their own weight. These particles settle and deposit under gravity, and are subsequently carried by the water flow into the sand-discharging branch tunnel 3 for temporary storage, achieving secondary separation.

[0067] S3. The low-sediment water, after being separated twice, flows upward through the vertical shaft 23, turns again, and is transported to the turbine generator set 6 via the power generation branch tunnel 5.

[0068] In or after S3, if the outlet gate 4 is open, the coarse and medium-sized sediment particles separated by the above two separations will be discharged into the downstream river channel 7 with the water flow; if the outlet gate 4 is closed, the coarse and medium-sized sediment particles separated by the above two separations will be temporarily stored in the sand discharge branch tunnel 3 on the upstream side of the outlet gate 4, and will be discharged into the downstream river channel 7 with the water flow after the outlet gate 4 is opened.

[0069] The water-sand separation method of this embodiment has the same beneficial effects as the water-sand separation device described above compared to the prior art, and will not be repeated here.

[0070] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A water-sand separation device, characterized in that, include: Main tunnel (1), which is used to connect the muddy river; The connecting structure (2) has a first interface (21), a second interface (22) and a shaft (23) that are interconnected, and the first interface (21) is connected to the main tunnel (1); The sand-drainage branch tunnel (3) is connected at one end to the second interface (22), and at the other end to the downstream river channel (7). The extension direction of the sand-drainage branch tunnel (3) is parallel to the extension direction of the main tunnel (1). An outlet gate (4) is provided in the sand discharge branch tunnel (3) to control the opening or closing of the sand discharge branch tunnel (3) between the second interface (22) and the downstream river channel (7); A power generation branch tunnel (5) is provided, one end of which is connected to the vertical shaft (23), and the other end of which is used to connect to the water turbine generator set (6). The axis of the vertical shaft (23) is set at an angle to the axis of the power generation branch tunnel (5); The connection between the vertical shaft (23) and the power generation branch tunnel (5) has a second arc structure (25). The minimum height difference between the end axis of the power generation branch tunnel (5) near the shaft (23) and the axis of the main tunnel (1) is greater than or equal to three times the diameter of the main tunnel (1).

2. The water-sand separation device according to claim 1, characterized in that, The connecting structure (2) also has a settling cavity (26), and the connection part of the first interface (21), the second interface (22) and the shaft (23) is the settling cavity (26); the radial cross section from the first interface (21) to the settling cavity (26) gradually expands, and the radial cross section from the settling cavity (26) to the shaft (23) gradually shrinks.

3. The water-sand separation device according to claim 2, characterized in that, The maximum radial cross-sectional area of ​​the settling cavity (26) is three times the radial cross-sectional area of ​​the main tunnel (1).

4. The water-sand separation device according to claim 2, characterized in that, The connection between the vertical shaft (23) and the first interface (21) has a first arc structure (24).

5. The water-sand separation device according to claim 1, characterized in that, The diameters of the sand-drainage branch tunnel (3) and the power generation branch tunnel (5) are less than or equal to the diameter of the main tunnel (1).

6. A water diversion power generation system, characterized in that, It includes a hydro-generator set (6) and a water-sand separation device as described in any one of claims 1 to 5.

7. A method for separating water and sediment, based on the water and sediment separation device according to any one of claims 1 to 5, characterized in that, Includes the following steps: The muddy river carrying sediment is transported through the main tunnel (1) to the connecting structure (2). The inertia of the sediment causes the coarse sediment particles in the water to be flushed into the sand discharge branch tunnel (3) connected to the connecting structure (2), thus achieving the first separation of the coarse sediment particles from the water. After the first separation, the sand-laden water flow turns from the second interface (22) of the connecting structure (2) and flows upward along the vertical shaft (23). Using gravity, the medium particles in the sand-laden water flow settle and are flushed into the sand discharge tunnel (3), thus achieving the second separation of medium particles in the sediment from the water. After two separations, the low-sediment-laden water flows through the vertical shaft (23) and is then transported to the turbine generator unit (6) via the power generation branch tunnel (5).

Images