Imported adaptive adjustable flow-guiding sand discharge tunnel gate structure

Abstract

This invention discloses an inlet adaptive adjustment guide-type sediment discharge tunnel gate structure, relating to the field of water conservancy engineering technology. It includes a sediment discharge tunnel body, characterized in that: the sediment discharge tunnel body comprises a second impeller, a second gate, a top water-blocking plate, and a guide weir; a second regulating gate is provided on the front side of the sediment discharge tunnel body; a second impeller is provided on the top of the second regulating gate; the top of the second impeller is welded to a second valve stem; the second valve stem is connected to the top of the second regulating gate; and a bottom guiding method is used to guide the bottom water with a high sediment content into the tunnel, improving sediment discharge efficiency; on the other hand, the elevation of the bottom guide opening is automatically controlled by the gate, allowing it to automatically adapt to the stratified characteristics of the incoming sediment content, achieving the purpose of automatically adapting to changes in incoming sediment and achieving precise and efficient sediment discharge. This solves the problem that traditional sediment discharge tunnel gate openings do not adequately consider the vertical position of the water flow with a high sediment content, lacking refined and adaptive scheduling measures.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, specifically to an inlet adaptive adjustment diversion-type sand discharge tunnel gate structure. Background Technology

[0002] Desilting tunnels are common hydraulic structures, often used in water conservancy projects on rivers with high sediment loads or those with low reservoir-to-sediment ratios. Desilting tunnels can be located at the lower part of the dam for direct sediment discharge, or they can be located on the side of the dam or even in the middle of the reservoir to divert sediment in advance. Improving sediment discharge efficiency and meeting maximum sediment discharge requirements through desilting tunnels has been a long-standing research focus, with the size and type of the inlet gate being crucial: an inlet that is too large results in less sediment and more water during flow, potentially leading to larger engineering workloads, water waste, and reduced sediment discharge efficiency; an inlet that is too small may result in insufficient sediment discharge, causing blockages during periods of high water and sediment. Research on inlet gate types focuses on flow safety under high head pressure.

[0003] When sediment inflow varies significantly, multiple sediment discharge tunnels are often installed in the dam body for sediment discharge. The number or location of these tunnels is adjusted according to the amount of sediment and the elevation of the water flow with higher sediment content to achieve rational sediment discharge. For advance sediment discharge on the lateral side of the dam and in the middle of the reservoir, due to space constraints and engineering control, only a single sediment discharge tunnel is often installed. Its operation is also relatively simple: it is activated when sediment discharge is needed and not activated when it is not needed. However, little consideration is given to whether the activation will result in high water consumption and low sediment discharge efficiency, or whether the gate opening corresponds to the vertical position of the water flow with higher sediment content. This lacks refined and adaptive operation measures. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an inlet adaptive adjustment guide-type desilting tunnel gate structure, which solves the problem mentioned in the background technology that the opening degree of traditional desilting tunnel gates does not adequately consider the vertical position of water flow with high sediment content, and lacks refined and adaptive scheduling measures.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an inlet adaptive adjustment guide-type sand discharge tunnel gate structure, comprising a sand discharge tunnel body, characterized in that: the sand discharge tunnel body includes a second rotating wheel, a second gate plate, a top water-blocking plate, and a guide weir; a second regulating gate is provided on the front side of the sand discharge tunnel body; a second rotating wheel is provided on the top of the second regulating gate; the top of the second rotating wheel is welded to a second valve stem; the second valve stem is connected to the top of the second regulating gate; the bottom of the second valve stem is rotatably connected to the top of the second gate plate; a guide weir is provided on one side of the second regulating gate; lateral water-blocking plates are provided on both sides of the guide weir; the top side of the lateral water-blocking plate is welded to both ends of the top water-blocking plate; the top water-blocking plate is located above the guide weir; a first regulating gate is provided at the bottom of the guide weir; the first regulating gate is connected to a first valve stem; a controller is connected to the top of the first valve stem; the bottom of the first valve stem is rotatably connected to the first gate plate; and the controller contains a drive device and a monitoring system.

[0006] Preferably, the bottom of the diversion weir is lower than the bottom of the main body of the sand discharge tunnel, and one side of the diversion weir has a sloping surface.

[0007] Preferably, the sand-drainage tunnel experimental method includes the following:

[0008] Step 1: The general open-type sand discharge tunnel is set up as a bottom-guided sand discharge tunnel main body to guide the bottom water with a large sand content into the sand discharge tunnel main body. In the sand discharge in the middle section of the reservoir, a bottom-guided sand discharge tunnel structure is set up. The sand discharge tunnel inlet is composed of a guide structure and a weir.

[0009] Step 2: The vertical distribution characteristics of sediment content under different sediment inflow conditions in the weak dynamic water flow of the reservoir area and the calculation formula of the stratification inflection point height were obtained. Considering the characteristics of weak water flow dynamics and fine sediment particles in the reservoir area, a flume test was carried out to investigate the vertical distribution characteristics of sediment content of fine sediment particles under weak dynamic conditions. The flume was 20cm wide, 25cm high, and 3.5m long. The flume bottom slope was variable, and the maximum flow rate was about 8m3 / h. The variation range of the flume bottom slope was 0% to 1%.

[0010] Step 3: Considering the typical suspended sediment particle size range (0.001mm to 0.1mm) in reservoir areas, the sand used in the experiment has a median particle size D of 0.065mm. The test conditions consider different combinations of inlet flow rate, sediment concentration, and water depth. The sediment concentration is measured along the vertical distribution using the ten-point method at a fixed cross-section. The sediment concentration shows obvious upper and lower stratification.

[0011] Step 4: Set the flow guiding structure of the flow-guiding sand discharge tunnel as an adjustable gate. Its opening can be adaptively adjusted according to the incoming water and sand conditions, so that the bottom height of the gate is just located at the inflection point of the sand content stratification in the incoming flow, so as to achieve a fine and efficient sand discharge effect.

[0012] Preferably, in step three, based on the fundamental theory of river dynamics, the vertical distribution characteristics of sediment concentration, i.e., the depth H0 of the vertical stratification inflection point of fine-grained sediment concentration, is related to factors such as the incoming flow velocity v, water depth h, incoming sediment concentration s, median particle size D, as well as conventional parameters such as sediment bulk density γs, water bulk density γ, and gravitational acceleration g.

[0013] H0=f(h,v,D,s,γ s ,γ,g) (1).

[0014] Preferably, in order to facilitate data regression, the above factors need to be dimensionless, so the sediment initiation formula (2) and sediment carrying force formula (3) are introduced.

[0015] Preferably, the formula for the sediment initiation velocity is:

[0016]

[0017] In the formula: vc is the initial flow velocity of sediment.

[0018] Preferably, the sand-carrying force formula is:

[0019]

[0020] In the formula: s m For sediment carrying capacity, k and m are constants, typically taken as 0.25 and 0.92 for reservoirs, and ω is the sediment settling velocity, which is related to D.

[0021] Preferably, substituting formula (3) into formula (1) for dimensionless transformation yields:

[0022] H0 / h=f(v / v c ,s / s m (4).

[0023] Preferably, the flow velocity, water depth, sediment concentration, and inflection point depth data obtained from the experimental statistics can be used to obtain the sediment concentration inflection point depth formula (5) through dimensionless transformation and least squares regression:

[0024]

[0025] The correlation was 0.89.

[0026] This invention provides an inlet adaptive adjustment guide-type sand discharge tunnel gate structure. It has the following beneficial effects:

[0027] This imported adaptive flow-adjusting desilting tunnel gate structure, through the combination of various components, addresses the differences in the vertical distribution characteristics of suspended matter under different sand inflow conditions. On the one hand, it uses bottom flow guidance to guide the bottom water with higher sand content into the tunnel, improving desilting efficiency. On the other hand, it automatically controls the elevation of the bottom flow-adjusting gate to adapt to the stratification characteristics of the incoming sand content, achieving the goal of automatically adapting to changes in incoming sand and achieving precise and efficient desilting. This solves the problem that traditional desilting tunnel gate openings do not adequately consider whether they correspond to the vertical position of water with higher sand content, lacking precise and adaptive scheduling measures. Attached Figure Description

[0028] Figure 1 This is a schematic cross-sectional view of the present invention;

[0029] Figure 2 This is a schematic diagram of the vertical distribution of suspended matter in a natural river.

[0030] Figure 3 This is a schematic diagram showing the vertical distribution of sand content;

[0031] Figure 4 This is a schematic diagram of sediment gradation.

[0032] Figure 5 A schematic diagram of sediment removal in the middle section of the reservoir area;

[0033] Figure 6 This is a plan view of the reservoir.

[0034] In the diagram, 1. Main body of the sand discharge tunnel; 2. Second regulating gate; 3. Second impeller; 4. Second valve stem; 5. Second gate plate; 6. Lateral water-blocking plate; 7. Top water-blocking plate; 8. Guide weir; 9. First regulating gate; 10. First gate plate; 11. First valve stem; 12. Controller. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1:

[0037] An imported adaptive adjustable guide-type sand discharge tunnel gate structure includes a sand discharge tunnel body 1, characterized in that: the sand discharge tunnel body 1 includes a second rotating wheel 3, a second gate plate 5, a top water-blocking plate 7, and a guide weir 8; a second regulating gate 2 is provided on the front side of the sand discharge tunnel body 1; a second rotating wheel 3 is provided on the top of the second regulating gate 2; the top of the second rotating wheel 3 is welded to a second valve stem 4; the second valve stem 4 is connected to the top of the second regulating gate 2; the bottom of the second valve stem 4 is rotatably connected to the top of the second gate plate 5; a guide weir 8 is provided on one side of the second regulating gate 2; lateral water-blocking plates 6 are provided on both sides of the guide weir 8; the top side of the lateral water-blocking plate 6 is welded to both ends of the top water-blocking plate 7; the top water-blocking plate 7 is located above the guide weir 8; a first regulating gate 9 is provided at the bottom of the guide weir 8; the first regulating gate 9 is connected to a first valve stem 11; a controller 12 is connected to the top of the first valve stem 11; the bottom of the first valve stem 11 is rotatably connected to the first gate plate 10; and the controller 12 is equipped with a drive device and a monitoring system.

[0038] The bottom of the diversion weir 8 is lower than the bottom of the main body 1 of the sand discharge tunnel, and one side of the diversion weir 8 is a sloping surface.

[0039] The water depth H0 corresponding to the inflection point of the sediment concentration distribution along the vertical line needs to be calibrated through a specialized flume test. The experimental method for the sediment discharge tunnel includes the following:

[0040] Step 1: The general open-type sand discharge tunnel is set up as the main body 1 of the bottom guide sand discharge tunnel, which guides the bottom water with a large sand content into the main body 1 of the sand discharge tunnel. In the sand discharge in the middle section of the reservoir, the bottom guide sand discharge tunnel structure is set up. The sand discharge tunnel inlet is composed of a guide structure and a weir.

[0041] Step 2: The vertical distribution characteristics of sediment content under different sediment inflow conditions in the weak dynamic water flow of the reservoir area and the calculation formula of the stratification inflection point height were obtained. Considering the characteristics of weak water flow dynamics and fine sediment particles in the reservoir area, a flume test was carried out to investigate the vertical distribution characteristics of sediment content of fine sediment particles under weak dynamic conditions. The flume was 20cm wide, 25cm high, and 3.5m long. The flume bottom slope was variable, and the maximum flow rate was about 8m3 / h. The variation range of the flume bottom slope was 0% to 1%.

[0042] Step 3: Considering the typical suspended sediment particle size range (0.001mm to 0.1mm) in a reservoir area, the sand used in the experiment had a median particle size D of 0.065mm. The experimental conditions considered different combinations of inlet flow rate, sediment concentration, and water depth. The sediment concentration was measured vertically at a fixed cross-section using a ten-point method. A clear stratification of sediment concentration was observed. (This is repeated in the original text.) Figure 3The arrow in the figure indicates the inflection point. The water depth H0 of the "inflection point" of sediment concentration stratification can be read from the figure.

[0043] Step 4: Set the flow guiding structure of the flow-guiding sand discharge tunnel as an adjustable gate. Its opening can be adaptively adjusted according to the incoming water and sand conditions, so that the bottom height of the gate is just located at the inflection point of the sand content stratification in the incoming flow, so as to achieve a fine and efficient sand discharge effect.

[0044] Step three, based on fundamental theories of river dynamics, relates the vertical distribution characteristics of sediment load, specifically the depth H0 of the vertical stratification inflection point for fine-grained sediment load, to factors such as inflow velocity v, water depth h, inflow sediment load s, median particle size D, as well as conventional parameters such as sediment bulk density γs, water bulk density γ, and gravitational acceleration g.

[0045] H0=f(h,v,D,s,γ s ,γ,g) (1).

[0046] To facilitate data regression, the above factors need to be dimensionless, so the sediment initiation formula (2) and sediment carrying force formula (3) are introduced.

[0047] The formula for the initial flow velocity of sediment is:

[0048]

[0049] In the formula: vc is the initial flow velocity of sediment.

[0050] The formula for sand-carrying force is:

[0051]

[0052] In the formula: s m For sediment carrying capacity, k and m are constants, typically taken as 0.25 and 0.92 for reservoirs, and ω is the sediment settling velocity, which is related to D.

[0053] Substituting formula (3) into formula (1) for dimensionless transformation, we get:

[0054] H0 / h=f(v / v c ,s / s m (4).

[0055] The flow velocity, water depth, sediment concentration, and inflection point depth data obtained from the experiments can be used to derive the sediment concentration inflection point depth formula (5) through dimensionless transformation and least squares regression:

[0056]

[0057] The correlation was 0.89.

[0058] Example 2:

[0059] The Upper Arun (UA) hydroelectric power station is located on the upper reaches of the Arun River, a tributary of the Koshi River in eastern Nepal, approximately 220 km from Kathmandu.

[0060] The Arun River has an average annual flow of 217 m³ / h. 3 / s, average annual runoff 6.86 billion m³ 3 The average annual sediment inflow into the reservoir above the dam site is 16.24 million tons, of which 13.81 million tons are suspended sediment and 2.43 million tons are bedload. The average annual suspended sediment concentration is 2.01 kg / m³. 3 The median suspended particle size is 0.057 mm. The UA hydropower station has a head of over 500 m for water diversion and power generation, and a reservoir capacity of approximately 5.07 million m³. 3 The reservoir has a sediment ratio of approximately 0.4 and is characterized by "high hydropower head, small reservoir capacity, high sediment content, and high sediment hardness".

[0061] To prevent siltation, a sediment discharge tunnel (SBT) was constructed, with its inlet located 1 km upstream of the dam on the left bank. It is a pressurized tunnel with an inlet bottom elevation of 1610 m. At a reservoir water level of 1625 m, the maximum discharge capacity of the sediment discharge tunnel is 822 m³ / s.

[0062] A 1:50 normal distribution model was used to simulate the sediment discharge effect of the reservoir. Moving bed tests were conducted using inflow rates of 1050 m³ / s, 750 m³ / s, 500 m³ / s, and 350 m³ / s. Sediment concentration samples were taken at the model inlet A (1.67 km from the dam), SBT outlet B (1.2 km from the dam), power station intake outlet C (0 km from the dam), upstream SBT D (1.38 km from the dam), downstream SBT E (0.96 km from the dam), upstream of the dam F (0.1 km from the dam), and bottom outlet G (0 km from the dam). The sediment concentration was tested using the drying method, and the sediment discharge effect was compared between the inlet of the sediment discharge tunnel with and without a guiding structure.

[0063] Compared to the case without a guide structure, the sand content of SBTs with guide structures increases to varying degrees with increasing inflow (SBT sand content increases by 9%, 4%, and 2%, respectively), while the sand content passing through the power plant decreases to varying degrees (power plant machine sand content decreases by 4%, 6%, and 1%, respectively). With increasing inflow, the increase or decrease in sand content of both SBTs and power plant machines also decreases.

[0064] In terms of sediment removal efficiency, the SBT with a flow guiding structure improves the overall sediment removal efficiency of the reservoir area compared to the SBT without a flow guiding structure, especially under high water and high sediment conditions (1050 m³ / s). The sediment removal efficiency for fine-particle sediment is significantly improved, increasing from approximately 62% to 78% for sediments smaller than 0.062 mm. For medium and low water conditions, the improvement is between 3% and 8%, as stratified flow is more likely to occur under high water and high sediment conditions. It is evident that the flow guiding structure can increase the sediment content in the sediment removal tunnel and improve the sediment separation effect, making it particularly suitable for high water and high sediment conditions where sediment removal is urgently needed.

[0065] Comparison table of sand removal efficiency under different working conditions

[0066]

[0067]

[0068]

[0069] Working principle: The side baffle plate 6 and the top baffle plate 7 mainly prevent water from entering the main body of the sand discharge tunnel 1 from the top and side of the first regulating gate 9. The water level and sediment content of the water flow are monitored by the monitoring system inside the controller 12. The controller 12 then transmits the signal to the internal drive device, which controls the first valve stem 11 to rotate. This allows the first regulating gate 9 to automatically adjust its opening according to the water flow and sediment content. The bottom water with a higher sediment content is guided from the reservoir area into the first regulating gate 9 and then into the diversion weir 8. The diversion weir 8 guides the water flow to flow backward from the bottom of the second regulating gate 2 into the main body of the sand discharge tunnel 1. The second gate plate 5 is moved up and down, thereby controlling the main switch of the diversion weir 8.

[0070] The present invention comprises: 1. a sand discharge tunnel main body; 2. a second regulating gate; 3. a second impeller; 4. a second valve stem; 5. a second gate plate; 6. a lateral water-blocking plate; 7. a top water-blocking plate; 8. a guide weir; 9. a first regulating gate; 10. a first gate plate; 11. a first valve stem; and 12. a controller. All components are general standard parts or parts known to those skilled in the art, and their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0071] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0072] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An inlet adaptive regulating diversion type sand discharge tunnel gate structure comprising a sand discharge tunnel main body (1), characterized in that: The sand discharge tunnel body (1) comprises a second rotating wheel (3), a second gate plate (5), a top water blocking plate (7) and a flow guide weir (8), the front side of the sand discharge tunnel body (1) is provided with a second adjusting gate (2), the top of the second adjusting gate (2) is provided with the second rotating wheel (3), the top of the second rotating wheel (3) is welded with a second valve rod (4), the second valve rod (4) is connected with the top of the second adjusting gate (2), the bottom of the second valve rod (4) is rotationally connected with the top of the second gate plate (5), one side of the second adjusting gate (2) is provided with the flow guide weir (8), the flow guide weir (8) is provided with a lateral water blocking plate (6) on both sides, one side of the top of the lateral water blocking plate (6) is welded with both ends of the top water blocking plate (7), the top water blocking plate (7) is arranged above the flow guide weir (8), the bottom end of the flow guide weir (8) is provided with a first adjusting gate (9), the first adjusting gate (9) is connected with a first valve rod (11), the top of the first valve rod (11) is connected with a controller (12), the bottom of the first valve rod (11) is rotationally connected with a first gate plate (10), the inside of the controller (12) is provided with a driving device and a monitoring system. The bottom of the flow guide weir (8) is lower than the bottom of the sand discharge tunnel body (1), one side of the flow guide weir (8) is a slope surface.

2. The self-adjusting inlet guide vanes structure of claim 1, wherein: The flow guide type sand discharge tunnel opening door structure is self-adaptive to adjust the elevation of the flow guide opening according to the stratification characteristics of the incoming flow, and the elevation is determined by a flume test, and the method comprises the following steps: Step one: the general open type sand discharge tunnel is arranged as a bottom flow guide type sand discharge tunnel body (1), the bottom flow guide type sand discharge tunnel body (1) is arranged to guide the water flow with high sediment concentration into the sand discharge tunnel body (1), and the bottom flow guide type sand discharge tunnel structure is arranged in the middle of the reservoir for sand discharge, and the inlet of the sand discharge tunnel is composed of a guide structure and a weir body; Step two: the vertical distribution characteristics of the sediment concentration under different incoming sediment conditions in the weak dynamic flow in the reservoir area and the calculation formula of the stratification inflection point height are obtained, the vertical distribution characteristics of the sediment concentration of the weak dynamic fine particle sediment is tested according to the characteristics of the weak dynamic flow and the fine particle sediment in the reservoir area, the flume is 20cm wide, 25cm high and 3.5m long, the flume bottom slope is variable, the maximum available flow is 8m³ / h, and the flume bottom slope changes in the range of 0-1%; Step three: considering that the particle size range of the suspended sediment in the general reservoir area is 0.001mm to 0.1mm, the sand gradation for the test is that the median particle size D is 0.065mm, different combinations of the inlet flow, sediment concentration and water depth are considered in the test, the ten-point method is used to measure the vertical distribution of the sediment concentration at a fixed section, and the sediment concentration appears obvious upper and lower stratification phenomena; Step four: the flow guide structure of the flow guide type sand discharge tunnel is arranged as an adjustable gate, the opening of the gate can be adaptively adjusted according to the incoming water and sediment, so that the height of the gate bottom is just located at the stratification inflection point of the incoming flow, and the effect of fine and efficient sand discharge is achieved.

3. The self-adjusting inlet guide vanes structure of claim 2, wherein: The step three is based on the basic theory of river dynamics, the vertical distribution characteristics of sediment concentration, that is, the vertical stratification inflection point depth H0 of fine particle sediment concentration is related to the conventional parameters of incoming flow velocity v, water depth h, incoming sediment concentration s, median particle size D, sediment bulk density γs, water bulk density γ and gravitational acceleration g, that is H0=f(h,v,D,s,γs,γ,g) (1).

4. The self-adjusting inlet guide vanes structure of claim 3, wherein: For the convenience of data regression, the above parameters: v, h, s, D, γ s are dimensionless, so the sediment incipient velocity formula (2) and the sediment carrying capacity formula (3) are introduced. The sediment incipient velocity formula is where: v c V is the threshold velocity of sediment The sediment carrying capacity formula is （3） where S m is the sediment carrying capacity, K and m are constants, usually taken as 0.25 and 0.92 for reservoirs, and ω is the sediment settling velocity, which is related to D.

5. The self-adjusting inlet guide vanes structure of claim 4, wherein: The formula (3) is substituted into the formula (1) for dimensionless, and the sediment concentration inflection point depth formula (5) can be obtained through dimensionless and least square method regression of the flow velocity, water depth, sediment concentration and inflection point depth data obtained through the flume test: H0 / h = f(v / v c ,s / S m ) (4).

6. The self-adjusting inlet adaptive flow-guiding sediment sluice gate structure according to claim 5, characterized in that: The correlation is 0.

89. ​

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