Groove head test device for testing ratio of jet flow to wall flow

Abstract

The invention discloses a ditch head test device for testing the ratio of jet flow to wall flow, which comprises a fixed base, the top end of the fixed base is fixedly connected with a fixed plate for monitoring, the fixed plate is provided with a plurality of first water tanks, the top end of the fixed base is fixedly connected with a connecting plate, the connecting plate is in sliding connection with the fixed plate, and the connecting plate is provided with a plurality of second water tanks. The top end of the connecting plate is rotationally connected with a second water tank through a rotating shaft; and the adjusting structure comprises a threaded sleeve rotationally connected to the top end of the fixed base, and the threaded sleeve is in threaded connection with a threaded rod. According to the invention, through simulating different ditch head vertical wall conditions and upstream incoming water conditions, the accurate measurement of the ratio of the wall flow to the jet flow is realized, and the test result provides a corresponding data basis for accurately simulating the accumulated high-precision data of the ditch head hydrodynamic process and for the mechanism research of ditch head traceability erosion and the construction of a prediction model.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural water conservancy, and in particular to a ditch head test device for testing the ratio of a jet flow to a wall flow. Background Art

[0002] Gully head upstream erosion is one of the main processes of gully erosion development, and it contributes significantly to regional erosion and sand production. The streams converging at the upstream of the gully head form waterfalls at the turning point of the gully head and erode the gully bed, forming a drop hole and expanding upstream, constantly eroding the lower soil of the gully head drop, causing the upper soil to become unstable and collapse. It is one of the main modes of gully head upstream erosion. The waterfall at the gully head can be divided into two parts: jet flow and wall flow. Current research generally believes that the jet flow directly scours the gully head and gully bed, promoting the development of drop holes; while the wall flow causes soil erosion and morphological changes at the gully head drop, and the impact of the wall flow on the development of drop holes in the gully bed is not considered.

[0003] The project team simulated the development process of ditch bed pits under the condition of jet flow alone through the existing flume simulation test. However, it was found in the test that even for the soil with the worst erosion resistance, under the condition of jet flow alone, the backtracking distance of the pits to the ditch wall was always less than the distance between the waterfall and the ditch head pit, and the pits and the ditch head pit did not contact each other, which is inconsistent with the phenomenon of pit development and erosion of the soil under the pit found in a large number of actual observations in the field. According to analysis, this is because the existing test equipment ignores the effect of wall flow on pit development. After the wall flow scours along the ditch head pit and enters the ditch bed area, it will continue to flow to the pit development area and further promote the backtracking development of the pit; and the changes in the wall flow flow and hydrodynamic characteristics will significantly affect its impact on the backtracking development of the pit.

[0004] In the prior art, the ratio of jet flow to wall flow is affected by the upstream water dynamics and the ditch head morphology; current jet flow / wall flow research mainly uses field in-situ / simulated ditch head areas for observation, but during the experiment, this method will erode the catchment area topography before reaching the ditch head turning point, causing changes in hydrodynamic parameters, and part of the runoff will infiltrate, resulting in errors between the actual waterfall flow and hydrodynamic characteristics and the design parameters; at the same time, the in-situ / simulated ditch head morphology is difficult to adjust, and it is difficult to conveniently simulate the impact of ditch heads of different morphologies on the jet flow and wall flow ratio; therefore, the development of an experimental device that can quickly and accurately simulate the distribution ratio of jet flow to wall flow under different upstream water and ditch head morphologies will help promote the accurate simulation of the waterfall development process, which is of great significance to the promotion of ditch head source erosion process and mechanism research. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings in the prior art and to provide a groove head test device for testing the ratio of jet flow to wall flow.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A trench head test device for testing the ratio of jet flow to wall flow, comprising:

[0008] A fixed base, the top of which is fixedly connected to a fixed plate, a plurality of first water tanks are provided on the fixed plate, a connecting plate is fixedly connected to the top of the fixed base, the connecting plate is slidably connected to the fixed plate, the top of the connecting plate is rotatably connected to a second water tank via a rotating shaft, a cover plate is fixedly clamped inside each of the first water tanks, and a through groove is provided on the cover plate, a stabilizing pool is fixedly installed on the top of the fixed base, and the stabilizing pool is connected to the second water tank via a pipeline;

[0009] The adjustment structure includes a threaded sleeve rotatably connected to the top of the fixed base, the upper thread of the threaded sleeve is connected to a threaded rod, the bottom end of the second water tank is fixedly connected to an adjustment plate, a connecting groove is provided on the adjustment plate, and the connecting groove passes through the adjustment plate, the top of the threaded rod extends to the inner side of the connecting groove, a connecting shaft is fixedly connected between the inner walls of the adjustment plate, the connecting shaft passes through the threaded rod and is rotatably connected to the threaded rod, and a transmission structure is installed on the threaded sleeve.

[0010] Preferably, the transmission structure includes a motor fixedly connected to the top of the fixed base, the output end of the motor is fixedly connected to a rotating rod, a fixed shaft is arranged between the threaded sleeve and the motor, the fixed shaft is rotatably connected to the top of the fixed base, a fixed gear is fixedly sleeved on the fixed shaft, a connecting gear corresponding to the fixed gear is fixedly sleeved on the threaded sleeve, and the fixed gear is meshed with the connecting gear, rotating wheels are fixedly sleeved on the fixed shaft and the rotating rod, the rotating wheels are connected to each other by a transmission belt, and a moving structure is installed on the rotating rod.

[0011] Preferably, the movable structure includes an adjusting gear fixedly sleeved on the rotating rod, a fixing rod is fixedly connected to the side wall of the fixing plate, an adjusting rack is fixedly connected to one end of the fixing rod away from the fixing plate, and the adjusting rack is meshed with the adjusting gear.

[0012] Preferably, a gradient plate is fixedly connected to the inner wall of each of the first water troughs, the gradient plate is arranged on one side of the first water trough close to the second water trough, and soil is laid inside each of the first water troughs.

[0013] Preferably, a sliding plate is fixedly connected to the side wall of the fixed plate, and a sliding groove matching the sliding plate is formed on the connecting plate.

[0014] Preferably, a water pump is provided on the second water tank.

[0015] Compared with the prior art, the beneficial effects of the present invention are: it can achieve effective and precise control of the groove head morphological conditions, and ultimately accurately measure the proportion and changing law of wall flow-jet flow under different flow conditions under different groove head morphological conditions, accumulate high-precision data for accurate simulation of the groove head hydrodynamic process, and provide a corresponding data basis for the mechanism research and prediction model construction of groove head source erosion. By incorporating the wall flow into the experimental process, it can not only effectively observe the proportion of wall flow-jet flow under different groove head vertical wall conditions, but also enable the wall flow to participate in the process of caving development, making the experiment more perfect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the three-dimensional structure of a trench head test device for testing the ratio of a jet flow to a wall flow proposed by the present invention;

[0017] Figure 2 A schematic diagram of the three-dimensional structure of a trench head test device for testing the ratio of a jet flow to a wall flow proposed by the present invention with the cover plate removed;

[0018] Figure 3 A schematic diagram of a partial left-view stereoscopic structure of a trench head test device for testing the ratio of a jet flow to a wall flow proposed by the present invention;

[0019] Figure 4 A schematic diagram of a right-side stereoscopic structure of a trench head test device for testing the ratio of a jet flow to a wall flow proposed by the present invention;

[0020] Figure 5 for Figure 2 Enlarged view of point A in the middle.

[0021] In the figure: 1 a fixed base, 2 a fixed plate, 3 a first water tank, 4 a connecting plate, 5 a second water tank, 6 a sliding plate, 7 a sliding slot, 8 an adjusting rack, 9 a fixed rod, 10 a fixed shaft, 11 a rotating wheel, 12 a transmission belt, 13 a fixed gear, 14 a threaded sleeve, 15 a threaded rod, 16 a connecting gear, 17 an adjusting plate, 18 a motor, 19 a rotating rod, 20 an adjusting gear, 21 a connecting slot, 22 a connecting shaft, 23 a slope plate, 24 a stabilizing pool, and 25 a rotating shaft. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0023] Reference Figures 1 to 4 , a trench head test device for testing the ratio of jet flow to wall flow, comprising:

[0024] A fixed base 1 is provided, and a fixed plate 2 is fixedly connected to the top of the fixed base 1 for monitoring. A plurality of first water tanks 3 are provided on the fixed plate 2. A connecting plate 4 is fixedly connected to the top of the fixed base 1. The connecting plate 4 serves as a groove head. The connecting plate 4 is slidably connected to the fixed plate 2. The top of the connecting plate 4 is rotatably connected to a second water tank 5 through a rotating shaft 25. The second water tank 5 is a closed water tank, and a small opening is provided at one end thereof close to the connecting plate 4. Figure 3 As shown, the second water tank 5 is connected with a stabilizing pool through a hose, and water flows from the second water tank 5 to the first water tank 3. A cover plate is fixedly clamped inside each first water tank 3, and a through groove is opened on the cover plate. Part of the water flows into the first water tank 3 from the through groove, and the other part flows away from the cover plate. The water entering the first water tank 3 is used to detect the wall flow rate, and the water flowing away from the cover plate is used to detect the waterfall flow rate, so that different tests can be carried out at the same time, and the cover plate can be disassembled to meet different experimental requirements. A stabilizing pool 24 is fixedly installed on the top of the fixed base 1. The stabilizing pool 24 is connected to 5 through a pipe. The pipe adopts a hose and can be retracted to ensure the connection between the stabilizing pool 24 and the second water tank 5.

[0025] The adjustment structure includes a threaded sleeve 14 rotatably connected to the top of the fixed base 1, the upper thread of the threaded sleeve 14 is connected to a threaded rod 15, the bottom end of the second water tank 5 is fixedly connected to an adjustment plate 17, a connection groove 21 is provided on the adjustment plate 17, and the connection groove 21 penetrates the adjustment plate 17, the top of the threaded rod 15 extends to the inner side of the connection groove 21, a connection shaft 22 is fixedly connected between the inner walls of the adjustment plate 17, the connection shaft 22 penetrates the threaded rod 15 and is rotatably connected to the threaded rod 15, and a transmission structure is installed on the threaded sleeve 14;

[0026] Under the action of the transmission structure, the threaded sleeve 14 rotates, while the threaded rod 15 is fixed, so the thread causes the threaded rod 15 to move. When the threaded rod 15 moves upward, it pushes the connecting shaft 22 and the adjustment plate 17 to move upward together, so that the second water tank 5 is tilted to change the angle of the second water tank 5, so that the simulation experiment can be more comprehensive.

[0027] The transmission structure includes a motor 18 fixedly connected to the top of the fixed base 1, a rotating rod 19 fixedly connected to the output end of the motor 18, a fixed shaft 10 is provided between the threaded sleeve 14 and the motor 18, the fixed shaft 10 is rotatably connected to the top of the fixed base 1, a fixed gear 13 is fixedly sleeved on the fixed shaft 10, a connecting gear 16 corresponding to the fixed gear 13 is fixedly sleeved on the threaded sleeve 14, and the fixed gear 13 is meshed with the connecting gear 16, a rotating wheel 11 is fixedly sleeved on both the fixed shaft 10 and the rotating rod 19, the rotating wheels 11 are connected to each other through a transmission belt 12, and a moving structure is installed on the rotating rod 19;

[0028] After the motor 18 is started, its output end drives the rotating rod 19 to rotate. Under the action of the rotating wheel 11 and the transmission belt 12, the fixed shaft 10 rotates accordingly. The rotation of the fixed shaft 10 causes the fixed gear 13 fixed thereon to rotate, thereby driving the connecting gear 16 to rotate together, so that the threaded sleeve 14 rotates;

[0029] The moving structure includes an adjusting gear 20 fixedly sleeved on the rotating rod 19, a fixing rod 9 is fixedly connected to the side wall of the fixing plate 2, an adjusting rack 8 is fixedly connected to one end of the fixing rod 9 away from the fixing plate 2, and the adjusting rack 8 is meshed with the adjusting gear 20;

[0030] When the rotating rod 19 rotates, the adjusting gear 20 fixedly sleeved thereon rotates, so that the adjusting rack 8 meshing with the adjusting gear 20 moves, driving the fixing rod 9 to move accordingly, so that the fixing plate 2 moves, and the other first water tank 3 moves to the second water tank 5, thereby reducing the trouble of changing the soil during the experiment;

[0031] A slope plate 23 is fixedly connected to the inner wall of each first water trough 3, and the slope is set to 30-90°. The slope plate 23 is arranged on one side of the first water trough 3 close to the second water trough 5, and soil is laid inside each first water trough 3;

[0032] Soil type selection can be based on a 1:1 million soil type map to systematically screen typical soil types in gully erosion development areas; the soil collected in the field is sieved through a 2 mm sieve and filled into the simulated gully bed in layers.

[0033] A sliding plate 6 is fixedly connected to the side wall of the fixed plate 2, and a sliding groove 7 matching the sliding plate 6 is opened on the connecting plate 4 to facilitate the movement of the fixed plate 2; a water pump is provided on the second water tank 5 to pump water into the second water tank 5 for a simulation experiment.

[0034] In the present invention, when the device is in use, water flows from the second water tank 5 to the first water tank 3 for mechanical energy experiment. During the experiment, the motor 18 is started. After the motor 18 is started, its output end drives the rotating rod 19 to rotate. Under the action of the rotating wheel 11 and the transmission belt 12, the fixed shaft 10 rotates accordingly. The rotation of the fixed shaft 10 will cause the fixed gear 13 fixed thereon to rotate, thereby driving the connecting gear 16 to rotate together, so that the threaded sleeve 14 rotates. After the motor 18 is started, its output end drives the rotating rod 19 to rotate. Under the action of the rotating wheel 11 and the transmission belt 12, the fixed shaft 10 rotates accordingly. The rotation of the fixed shaft 10 will cause the fixed gear 13 fixed thereon to rotate, thereby driving the connecting gear 16 to rotate together, so that the threaded sleeve 14 rotates. At the same time, when the rotating rod 19 rotates, the adjusting gear 20 fixedly sleeved thereon rotates, so that the adjusting rack 8 meshing with the adjusting gear 20 moves, driving the fixed rod 9 to move accordingly, so that the fixed plate 2 moves, and the other first water tank 3 moves to the second water tank 5, reducing the trouble of changing the soil during the experiment.

[0035] After clarifying the distribution ratio of jet flow and wall flow of a certain shaped ditch head under a determined flow rate, the improved device was placed above the simulated ditch bed to carry out a simulation test of cavitation development; each group of tests was planned to be flushed for 30 minutes, and the flow rate and ditch head shape remained unchanged during the test; the test monitored the flow of the jet flow and wall flow every 3 minutes, and the flow velocity, runoff width and runoff depth of the wall flow were monitored.

[0036] The total number of tests was: 5 (flow rate) × 10 (fall shape) × 4 (surface treatment of flumes 4 and 5: smooth surface and 3 soils with different particle gradations) = 200 groups.

[0037] The details are as follows:

[0038] 1. Simulate the groove head shape

[0039] By adjusting the water tanks 4 and 5, different ditch head drop shapes can be simulated.

[0040] 1. Keep the water tank 4 vertical and adjust the slope of the water tank 5: 2 degrees, 5 degrees, 8 degrees, 15 degrees, 25 degrees.

[0041] 2. The slope of the water trough 5 is 5 degrees, and the angles between the water trough 4 and the ground are: 90 degrees, 75 degrees, 60 degrees, 45 degrees, and 30 degrees.

[0042] 2. Sink surface roughness:

[0043] The following 4 different treatments are performed on the sink surface.

[0044] 1. Smooth surface: the original surface of the sink material.

[0045] 2. Simulate soil surface: fix soil particles of different soil types on the surface of water tanks 4 and 5 with glue, so that the surface roughness of the water tank is close to the natural soil surface. The soil types selected are: dry red soil, brown soil and black felt soil, which are the main soil types for gully erosion development in the Hengduan Mountain area.

[0046] 3. Flow setting:

[0047] According to the previous ditch head runoff flow, five test flow rates were designed: 30, 60, 100, 150, 200 and 250 l.min -1 .

[0048] 4. Hydraulic parameters monitoring:

[0049] Under the conditions of the determined ditch head shape, flume surface roughness and flow rate, a water discharge test is conducted. The water level in the runoff pool (2) is monitored every 3 minutes, the flow increase is calculated, and the flow velocity (staining method), runoff width and runoff depth (ruler measurement) of the wall flow in the flume 4 are monitored. The monitoring is repeated 3 times to obtain the average value. At the same time, the water temperature and the angle of incidence of the waterfall are measured. Other hydraulic parameters used for calculation include the Reynolds number, the Froude number, the runoff shear force, the runoff power, the unit runoff power, etc., which can be calculated and obtained based on the flow velocity, the runoff depth, the water temperature and the flume slope.

[0050] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A groove head test device for testing the ratio of jet flow to wall flow, characterized in that: include: A fixed base (1), the top of the fixed base (1) is fixedly connected to a fixed plate (2) for monitoring, the fixed plate (2) is provided with a plurality of first water tanks (3), the top of the fixed base (1) is fixedly connected to a connecting plate (4), the connecting plate (4) is slidably connected to the fixed plate (2), the top of the connecting plate (4) is rotatably connected to a second water tank (5) via a rotating shaft (25), each of the first water tanks (3) is fixedly clamped with a cover plate inside, and a through groove is provided on the cover plate, a stabilizing pool (24) is fixedly installed at the top of the fixed base (1), and the stabilizing pool (24) is connected to the second water tank (5) via a pipeline; The adjusting structure comprises a threaded sleeve (14) rotatably connected to the top of a fixed base (1); the upper thread of the threaded sleeve (14) is connected to a threaded rod (15); the bottom end of the second water tank (5) is fixedly connected to an adjusting plate (17); a connecting groove (21) is provided on the adjusting plate (17); the connecting groove (21) penetrates the adjusting plate (17); the top end of the threaded rod (15) extends to the inner side of the connecting groove (21); a connecting shaft (22) is fixedly connected between the inner walls of the adjusting plate (17); the connecting shaft (22) penetrates the threaded rod (15) and is rotatably connected to the threaded rod (15); and a transmission structure is installed on the threaded sleeve (14).

2. A groove head test device for testing the ratio of jet flow to wall flow according to claim 1, characterized in that: The transmission structure comprises a motor (18) fixedly connected to the top of a fixed base (1); the output end of the motor (18) is fixedly connected to a rotating rod (19); a fixed shaft (10) is arranged between the threaded sleeve (14) and the motor (18); the fixed shaft (10) is rotatably connected to the top of the fixed base (1); a fixed gear (13) is fixedly sleeved on the fixed shaft (10); a connecting gear (16) corresponding to the fixed gear (13) is fixedly sleeved on the threaded sleeve (14); the fixed gear (13) is meshed with the connecting gear (16); rotating wheels (11) are fixedly sleeved on both the fixed shaft (10) and the rotating rod (19); the rotating wheels (11) are connected to each other via a transmission belt (12); and a moving structure is installed on the rotating rod (19).

3. A groove head test device for testing the ratio of jet flow to wall flow according to claim 2, characterized in that: The movable structure comprises an adjusting gear (20) fixedly sleeved on a rotating rod (19); a fixing rod (9) is fixedly connected to a side wall of the fixing plate (2); an adjusting rack (8) is fixedly connected to one end of the fixing rod (9) away from the fixing plate (2); and the adjusting rack (8) is meshed with the adjusting gear (20).

4. A groove head test device for testing the ratio of jet flow to wall flow according to claim 1, characterized in that: A gradient plate (23) is fixedly connected to the inner wall of each of the first water troughs (3), the gradient plate (23) being arranged on one side of the first water trough (3) close to the second water trough (5), and soil is laid inside each of the first water troughs (3).

5. A groove head test device for testing the ratio of jet flow to wall flow according to claim 1, characterized in that: A sliding plate (6) is fixedly connected to the side wall of the fixed plate (2), and a sliding groove (7) matching the sliding plate (6) is formed on the connecting plate (4).

6. A groove head test device for testing the ratio of jet flow to wall flow according to claim 1, characterized in that: The second water tank (5) is provided with a water pump.

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