A device for measuring the lateral distribution of water flow per unit width in a water tank with vegetation

Abstract

This invention discloses a device for measuring the transverse distribution of unit width flow rate in a vegetated water flow system. The device is longitudinally arranged with a uniform flow control zone, a vegetated water flow simulation zone, and a thin-walled weir zone. Multiple thin-walled weirs are evenly distributed at the tail end of the thin-walled weir zone, and weir plates extend forward from the thin-walled weirs into the vegetated water flow simulation zone. A water level regulating device is installed at the connection point between adjacent weir plates and the vegetated water flow simulation zone. A first water level gauge group is located in the first 1 / 3 of the vegetated water flow simulation zone, a second water level gauge group is located in the second 2 / 3, a third water level gauge group is located in the inlet area at the front of the thin-walled weir zone, and a movable fourth water level gauge group is located in the thin-walled weir zone. The device is simple and easy to implement, and the water level regulating device has a simple structure, making it suitable for reducing the influence and errors of experimental devices in various complex water flow structures. The device offers rigorous scientific technology, simple operation, wide applicability, and strong applicability, facilitating physical model experiments.

Description

Technical Field

[0001] This invention relates to a device for measuring the lateral distribution of water flow per unit width in a trough with vegetation, belonging to the fields of hydraulics and river dynamics. Background Technology

[0002] Ideally, the unit width flow distribution of a cross section can be determined by dividing the cross section laterally and based on the product of flow velocity and water-passing area, where the flow velocity can be obtained using a flow velocity measuring device. For example, CN109612685A discloses an integrated measuring device and method for flow velocity and depth in a flume test. This integrated measuring device for flow velocity and depth in a flume test includes a measuring device, which includes a measuring instrument and a monitoring probe, and a switching component for switching between velocity and depth measurement; it also includes an adjusting device for adjusting the position of the measuring device, including a left-right position adjustment component, a front-back position adjustment component, and a height adjustment component; the switching component is connected to the height adjustment component. The measuring instrument and monitoring probe used in this device are disclosed in CN206515206U, which discloses a weir seepage flow measuring device, including: a mounting frame, a processor, a probe, a probe motion control module, a liquid level detection module, a grating ruler, a start button, and a display module. This device uses a probe and a grating ruler, both of which determine the flow rate by the product of flow velocity and water-passing area. When conducting vegetation flow experiments in a flume, vegetation alters the flow structure, and the flow velocity measured in the vegetated area cannot be used to estimate the unit width flow rate. Therefore, a new measurement method must be adopted for the unit width flow rate of vegetation flow in the flume. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a device for measuring the lateral distribution of water flow per unit width in a water tank with vegetation.

[0004] Technical Solution: The present invention provides a device for measuring the transverse distribution of single-width flow rate of vegetation water flow in a water tank, comprising a water tank, wherein a uniform flow control zone, a vegetation water flow simulation zone, and a thin-walled weir zone are sequentially arranged within the water tank. The bottoms of the uniform flow control zone and the vegetation water flow simulation zone are raised by 1-1.5m. Multiple thin-walled weirs are uniformly arranged at the tail end of the thin-walled weir zone. The thin-walled weirs are connected forward by weir plates extending to the vegetation water flow simulation zone. A water level regulating device is provided at the connection between two adjacent weir plates and the vegetation water flow simulation zone. A first water level gauge group is provided at the front 1 / 3 of the vegetation water flow simulation zone, a second water level gauge group is provided at the 2 / 3 of the vegetation water flow simulation zone, a third water level gauge group is provided at the inlet area at the front end of the thin-walled weir zone, and a movable fourth water level gauge group is also provided in the thin-walled weir zone.

[0005] Furthermore, the water level regulating device includes a lifting plate and a control rod, the lifting plate being connected to the control rod, which ensures that the lifting plate can rise or fall slightly under the action of the control rod.

[0006] Furthermore, the distance of the rise or fall is within 1 cm, and the lifting plate must ensure that the water flows freely after passing through the lifting plate.

[0007] Furthermore, the height of the thin-walled weir must ensure that the water outflow is free flow.

[0008] Furthermore, when the water flow rate is small, a thin-walled triangular weir is used, and when the water flow rate is large, a thin-walled rectangular weir is used.

[0009] Furthermore, the number of water level gauges in the first, second, third, and fourth water level gauge groups is one less than the number of weir plates.

[0010] Furthermore, the uniform water flow control zone includes a water stabilizing grid and a water stabilizing baffle, which are perpendicularly connected and the water stabilizing baffle evenly separates the water stabilizing grid.

[0011] Furthermore, the water-stabilizing grid has evenly distributed small circular holes.

[0012] Furthermore, the vegetation-water flow simulation zone is divided into three parts in the longitudinal direction: an inlet adjustment section, an experimental measurement section, and a connecting section, all of which are equipped with simulated vegetation.

[0013] Furthermore, the fourth water level gauge group was used to measure the water level at a location more than three times the maximum experimental head of the thin-walled weir upstream.

[0014] This invention proposes a method for measuring the unit width flow rate at different locations on a cross-section using multiple parallel triangular or rectangular thin-walled weirs. When using this method, a well-designed measuring device is necessary, paying particular attention to the errors and influences caused by water level differences. Therefore, it is crucial to minimize the interference of the measuring device on the experimental water flow and ensure the accuracy of the weir measurements. A water level adjustment device is added to regulate the water level at different locations on the cross-section, ensuring that the lateral water level distribution in the adjustment section is consistent with that in the experimental section. Parallel thin-walled triangular or rectangular weirs are used, and the lateral distribution of the unit width flow rate in the flume vegetation experiment is measured through the water head above the weirs.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0016] (1) The device of the present invention is simple and easy to design, and can reduce the influence of the experimental device on the water flow, thereby obtaining more accurate experimental data.

[0017] (2) The water level adjustment device used in the present invention has a simple structure and can be used to reduce the influence and error of the experimental device in various complex water flow structures.

[0018] (3) The flow rate measured by the thin-walled weir method of the present invention is accurate, and the measurement method is simple and has a wide range of applications.

[0019] (4) The device of the present invention provides a rigorous scientific approach, a simple operation method, a wide range of applications, and strong applicability, making it convenient to carry out physical model experiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the plan view of the transverse distribution measurement device for water flow unit width of vegetation in the water tank according to the present invention.

[0021] Figure 2 This is a side view of the device for measuring the lateral distribution of water flow unit width in vegetation in the water tank according to the present invention.

[0022] Figure 3 This is a side view of the water level regulating device;

[0023] Figure 4 A schematic diagram of the water flow uniform inlet controller;

[0024] Figure 5 This is a schematic diagram of the front elevation of the thin-walled weir channel area;

[0025] Figure 6 This is a physical image of the device for measuring the lateral distribution of water flow per unit width in vegetation under the present invention. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0027] like Figure 1 , 6 As shown, the inventor discloses a device for measuring the lateral distribution of unit width flow rate of vegetation water flow in a water tank. The device includes a water tank, within which are sequentially arranged a uniform flow control zone 1, a vegetation water flow simulation zone 2, and a thin-walled weir zone 3. The bottoms of the uniform flow control zone 1 and the vegetation water flow simulation zone 2 are raised to a height of 1-1.5m. The longitudinal length of the uniform flow control zone 1 is at least 0.5m, the longitudinal length of the vegetation water flow simulation zone 2 is at least 5m, and the longitudinal length of the thin-walled weir zone 3 is at least 3m.

[0028] like Figure 1-4 As shown, the uniform water flow control zone 1 includes a water-stabilizing grid 101 and a water-stabilizing baffle 102. The water-stabilizing grid (1) and the water-stabilizing baffle 102 together form a uniform water flow inlet controller to ensure that the water flow can enter the vegetation simulation section uniformly and eliminate the influence of uneven water inflow on the water flow conditions of the experimental measurement section. The water-stabilizing baffle 102 evenly separates the water-stabilizing grid 101. The water-stabilizing grid 101 and the water-stabilizing baffle 102 are perpendicularly connected. The water-stabilizing grid 101 has uniformly distributed small circular holes. When the water-stabilizing baffle 102 is perpendicularly connected to the water-stabilizing grid 101, it is necessary to ensure that the number of small holes between any two adjacent water-stabilizing baffles 102 is the same (e.g., Figure 4 (As shown).

[0029] like Figure 1-2 As shown, the vegetation-flow simulation zone 2 is longitudinally divided into three equal parts: an inlet adjustment section, an experimental measurement section, and a connecting section. A first water level gauge group 202 is installed at the first 1 / 3 of the vegetation-flow simulation zone 2, and a second water level gauge group 203 is installed at the 2 / 3 of the vegetation-flow simulation zone 2. The inlet adjustment section effectively avoids interference from inlet flow conditions on the vegetation-flow, the experimental measurement section is the main experimental measurement area, and the connecting section is used to reduce the influence of the water level adjustment device on the experimental measurement section. Simulated vegetation 201 is installed in all three parts of the vegetation-flow simulation zone 2.

[0030] like Figure 1-3 As shown in Figures 5-6, multiple thin-walled weirs 301 are evenly distributed at the tail end of the outlet area of ​​the thin-walled weir channel area 3. Each thin-walled weir 301 is connected forward to a weir plate 302 extending to the vegetation water flow simulation area 2. A small weir channel area is formed between two adjacent weir plates 302. A water level regulating device is provided at the connection between two adjacent weir plates 302 and the vegetation water flow simulation area 2. The water level regulating device includes a lifting plate 303 and a control rod 304. The lifting plate 303 is connected to the control rod 304 (e.g., ...). Figure 3 (As shown). The lifting plate 303 is connected to the tail end of the vegetation water flow simulation zone 2 by a hinge or other similar parts, ensuring that the lifting plate 303 can rise or fall slightly (within 1cm) under the action of the control rod 304. The lifting plate 303 has a certain height, generally 2-5cm, to ensure that the water flows freely after passing through the lifting plate. A third water level gauge group 305 is provided in the water inlet area at the front end of the thin-walled weir channel zone 3, and a movable fourth water level gauge group 306 is also provided in the thin-walled weir channel zone 3. The height of the thin-walled weir 301 must ensure that the water outflow is free. A triangular thin-walled weir is used when the water flow rate is small, and a rectangular thin-walled weir is used when the water flow rate is large. The thin-walled weir channel 3 has a certain length, generally 5-7 times the head of the water above the weir, ensuring that the measuring position of the fourth water level gauge group 306 is more than three times the maximum experimental head of the weir upstream of the thin-walled weir 301, and that the water flow at the fourth water level gauge group 306 is minimally affected by the drop from the lifting plate 303. The number of water level gauges in the first water level gauge group 202, the second water level gauge group 203, the third water level gauge group 305, and the fourth water level gauge group 306 is consistent with the number of small weir channels, and they are evenly distributed.

[0031] The device operates by the following steps:

[0032] The influent water uniformly flows into the vegetation water flow simulation area 2 through the water flow uniform inlet controller in the water flow uniform control area 1, forming a stable vegetation water flow structure. Multiple groups of water level heights are measured by the first water level gauge group 202, and then multiple groups of water level heights are measured by the second water level gauge group 203. Furthermore, the lifting plate 303 is adjusted to rise or fall slightly through the control rod 304, so that the water level measured by the third water level gauge group 305 forms a straight line longitudinally with the water level heights measured by the first water level gauge group 202 and the second water level gauge group 203, that is, to ensure that the water flow gradients in the experimental measurement sections and the connection sections of different partitions are consistent; the water flow freely drops to the thin-walled weir tank area 3 after passing through the lifting plate 303 and freely discharges at the thin-walled weir 301 at the end of the thin-walled weir tank area 3 (a triangular thin-walled weir is used when the flow rate is small, and a rectangular thin-walled weir is used when the flow rate is large); multiple weir water heads of the small weir tank area are measured by the fourth water level gauge group 306 at a position more than three times the maximum measured weir head of the experiment upstream of the thin-walled weir 301, and the single-width flow rate of multiple areas can be calculated by using the calibrated empirical formula, that is, the formula shown below.

[0033]

[0034] Among them, Q is the single-width flow rate of the water flow, H0 is the water level height at a position more than three times the maximum measured weir head of the experiment where the simulation curve has an obvious turning point, H is the water level height at a position more than three times (preferably 3 - 4 times) the maximum measured weir head of the experiment, C1 is the coefficient of the simulation function when H ≥ H0 of the simulation curve, C2 is the coefficient of the simulation function when H < H0 of the simulation curve, n is the exponent of the simulation function when H ≥ H0 of the simulation curve, m is the exponent of the simulation function when H < H0 of the simulation curve, and C1, C2, m, n, and H0 are all constants.

[0035] Due to the relatively stable head - flow rate relationship, the thin-walled weir flow is usually used as an effective water measurement tool in hydraulic model tests or field measurements. Generally, the cross-sectional shape of the water passing section at the top of the weir crest of the thin-walled weir 301 is often rectangular or triangular, which are respectively called rectangular thin-walled weir and triangular thin-walled weir. When the required measured flow rate is small (e.g., Q < 0.05 m 3 / s), a triangular thin-walled weir is used, and a rectangular thin-walled weir is used when the flow rate is large. The purpose of calibration is to calibrate the head - flow rate relationship curve of the thin-walled weir 301. The water flow at the inlet of the water tank ranges from a large flow rate of 120 m 3 / h to a small flow rate of 30 m 3 / h, with an interval of every 10 m 3 / h, a total of 10 groups of flow rates. The water level measurement point is at a position more than three times the average value of the maximum head height measured at the weir mouth (more than three times the maximum measured weir head of the experiment) upstream of the thin-walled weir 301. The calibration experiment should finally obtain two flow rate - water level height curves, and the fitted empirical formula should be in good agreement with the scattered data of the experiment. Finally, the empirical formula shown above should be obtained.

Claims

1. A device for measuring the lateral distribution of water flow unit width in a water tank, comprising a water tank, characterized in that, The water tank is provided with a uniform water flow control zone (1), a vegetation water flow simulation zone (2), and a thin-walled weir zone (3) in sequence. The bottom of the uniform water flow control zone (1) and the vegetation water flow simulation zone (2) is raised by 1-1.5m. Multiple thin-walled weirs (301) are uniformly provided at the tail end of the thin-walled weir zone (3). The thin-walled weirs (301) are connected to weir plates (302) extending forward to the vegetation water flow simulation zone (2). A water level regulating device is provided at the connection between two adjacent weir plates (302) and the vegetation water flow simulation zone (2). A first water level gauge group (202) is provided at the front 1 / 3 of the vegetation water flow simulation zone (2), a second water level gauge group (203) is provided at the 2 / 3 of the vegetation water flow simulation zone (2), a third water level gauge group (305) is provided at the front water inlet area of ​​the thin-walled weir zone (3), and a movable fourth water level gauge group is also provided in the thin-walled weir zone (3). The water level regulating device includes a lifting plate (303) and a control rod (304). The lifting plate (303) is connected to the control rod (304) to ensure that the lifting plate (303) can rise or fall slightly under the action of the control rod (304). The distance of the rise or fall is within 1 cm. The lifting plate (303) must ensure that the water flow falls freely after passing through the lifting plate (303). The height of the thin-walled weir (301) must ensure that the water flow out is free. When the water flow rate is small, the thin-walled weir (301) adopts a thin-walled triangular weir. When the water flow rate is large, the thin-walled weir (301) adopts a thin-walled rectangular weir. The vegetation water flow simulation area (2) is divided into three parts in the longitudinal direction: the inlet adjustment section, the experimental measurement section and the connecting section. The inlet adjustment section, the experimental measurement section and the connecting section are all equipped with simulated vegetation (201).

2. The device for measuring the lateral distribution of water flow unit width in vegetation under water tanks according to claim 1, characterized in that, The number of water level gauges in the first water level gauge group (202), the second water level gauge group (203), the third water level gauge group (305) and the fourth water level gauge group (306) is one less than the number of weir plates (302).

3. The device for measuring the lateral distribution of water flow unit width in vegetation under water tanks according to claim 1, characterized in that, The uniform water flow control zone (1) includes a water stabilizing grid (101) and a water stabilizing baffle (102), which are perpendicularly connected and the water stabilizing baffle (102) evenly separates the water stabilizing grid (101).

4. The device for measuring the transverse distribution of water flow unit width in vegetation under water tanks according to claim 3, characterized in that, The water stabilizing grid (101) has evenly distributed circular holes.

5. The device for measuring the lateral distribution of water flow unit width in vegetation under a water tank according to claim 1, characterized in that, The fourth water level gauge group (306) was used to measure the water level at a location more than three times the maximum experimental head of the thin-walled weir (301) upstream.

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