Hydraulic model for researching coarse particle conveying characteristics of sand-containing water flow of bifurcated pipeline

Abstract

The invention relates to a hydraulic model, in particular to a hydraulic model for studying the coarse particle conveying characteristic of sand-containing water flow of a bifurcated pipeline, and belongs to the field of hydraulic engineering, and the IPC (International Patent Classification) number of the hydraulic model is E02B 1 / 02. According to the hydraulic model, through the water inlet and outlet pool system, the water transfer pipeline system, the coarse particle feeding port, the movable and telescopic supports and the like, rapid, convenient and stable conversion of test working conditions of different branch pipeline angles, different overall inclination angles and different pipeline inflow and outflow forms can be achieved. By adopting the closed rectangular glass water tank, the distortion of shot pictures caused by refractive indexes of different materials such as organic glass and water flow is reduced, and the observation precision of the high-speed camera can be improved. Water can be transferred back and forth among the three groups of water inlet and outlet pools through the transfer pipelines and the transfer valves, so that the cyclic utilization of water flow is realized, and the effect of saving water resources is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to a hydraulic model, in particular to a hydraulic model for studying the coarse particle transport characteristics of the sediment-laden flow in a branched pipeline, and belongs to the field of hydraulic engineering, and the IPC international patent classification number is E02B 1 / 02. BACKGROUND

[0002] According to the Sediment Manual (Sediment Professional Committee of China Water Conservancy Society, Beijing: China Environmental Science and Technology Publishing House, 1992.04), the particles with a particle size of 2mm-20mm are called coarse particles. The engineering application of coarse particle transport in a pipeline sediment-laden flow is widely used, such as pipeline desilting and sediment discharge of rivers, lakes and reservoirs, deep-sea mining pipeline lifting, and coal pipeline transportation, etc. Compared with highway, railway, waterway and air transportation, pipeline transportation has the advantages of large transportation capacity and low cost, and has become the fifth transportation mode. Among them, the pipeline network engineering composed of branched pipelines has the functions of flow splitting and flow converging, and has a large transportation capacity and a wide coverage, and is widely used in dredging, mining, municipal and industrial fields.

[0003] The most basic form of branched pipeline is T-shaped or Y-shaped three-way pipeline, which is widely used to change the motion direction of the transported medium to play the role of flow splitting or flow converging. Existing scholars mainly carry out related research on the transport characteristics of branched pipelines through numerical simulation and physical model test. Numerical simulation is to build a numerical calculation model of branched pipeline transport through computer related language program. Physical model test is to build a physical branched pipeline model test device to carry out research. The existing model test device is mainly for the research on the transport process of water flow, gas and liquid two-phase flow in the branched pipeline.

[0004] The reservoir, river and seabed deposits are complex and contain sediment particles of different particle sizes, especially the tail of the mountainous reservoir and the silt body in the variable backwater area contain many large-diameter pebble coarse particles; the coarse particles are transported into the pipeline with high sediment-laden flow during the reservoir desilting, the Yellow River diversion project and deep-sea mining. In the coal pipeline engineering, part of the coal is supplied to the thermal power plant, and the particles are relatively coarse due to the difficulty in dehydration; another part is supplied to the coal chemical plant, and the particles are very fine, and the two kinds of graded materials are mixed with water in the pipeline for transportation. Fine particles and water form high sediment-laden flow, and coarse particles form a three-phase mixture with a broken grading.

[0005] The following gives the search results of the related literature on the test device for studying the transport characteristics of T-shaped or Y-shaped branched pipeline, the selection of calculation parameters and the post-processing method of test data:

[0006] [1] Chen W Y, Lv H X, Shi X, et al. Experimental study on local head loss coefficient of equal-diameter PVC tee pipe[J]. Irrigation and Drainage, 2013, 32(01): 128-130.

[0007] [2] Shi happy, Lü Hongxing, Zhu Delan, et al. Analysis of water flow resistance and flow characteristics of PVC tee pipes [J]. Transactions of the Chinese Society for Agricultural Machinery, 2013, 44(01):73-79+89.

[0008] [3] Chen Jianglin, Lü Hongxing, Shi happy, et al. Numerical simulation and experimental study on hydraulic characteristics of T-type tee pipe [J]. Transactions of the Chinese Society of Agricultural Engineering, 2012, 28(05):73-77.

[0009] [4] Shi happy, Lü Hongxing, Zhu Delan, et al. Experimental and numerical simulation of hydraulic transient conditions in branched pipe networks [J]. Journal of Irrigation and Drainage Machinery Engineering, 2013, 31(05):406-412.

[0010] [5] L, L, I,et al.Experimental and numerical investigation of mixing phenomena in double-tee junctions[J].Water,2019,11(6):1198.

[0011] [6]Ma L, He L, Luo X, et al. Experimental investigation of gas-liquidtwo-phase splitting in parallel pipelines with risers[J]. Chemical Engineering Research and Design, 2020, 161: 75-89.

[0012] [7] Su Heng, Qu Yegao, Zhou Shaochong, et al. Experimental study on flow-induced vibration of two-phase flow in horizontal T-tube [J]. Acta Aerodynamica Sinica, 2021, 39(03):130-137.

[0013] [8] Liu Shengchun, Song Ming, Dai Baomin, et al. Simulation and experimental study on pressure drop characteristics of ice slurry flow in pipeline [J]. Journal of Refrigeration, 2018, 39(02):61-67.

[0014] [9]Kumano H,Kobayashi T,Morimoto T,et al.Experimental study on flowcharacteristics of ice slurry through a T-junction Part I:Laminar flow[J].International Journal of Refrigeration,2020,116:89-95.

[0015]

[10] Duan G, Liu Z, Chen G, et al. Experimental investigation of gas-solidtwo-phase flow in Y-shaped pipeline[J]. Advanced Powder Technology, 2010, 21: 468-476.

[0016] Currently, there is no relevant model test device for three-phase mixtures consisting of water, fine particles, and coarse particles, i.e., coarse particles in sand-laden water flow. Furthermore, existing research mainly focuses on bifurcation pipes arranged vertically or horizontally, with little attention paid to bifurcation pipes with an overall inclined slope, while in engineering practice, inclined sections are unavoidable in pipe system layouts. However, there is currently no simple, practical, and convenient test device for studying the transport characteristics of coarse particles in sand-laden water flow through bifurcation pipes. Summary of the Invention:

[0017] This invention addresses the aforementioned problems and aims to provide a hydraulic model for studying the coarse-particle transport characteristics of sand-laden water in bifurcated pipelines. This model can study the transport process in bifurcated pipelines with different inclination angles, allows for rapid setup of different research conditions, and is simple, practical, and convenient to operate. The technical solution of this invention is as follows:

[0018] A hydraulic model for studying the coarse particle transport characteristics of sand-laden water flow in a bifurcated pipeline includes an inlet and outlet water tank system, a test pipeline system, and a water diversion pipeline system. The inlet and outlet water tank system includes a No. 1 water tank, a No. 2 water tank, and a No. 3 water tank. The test pipeline system includes a No. 1 test pipeline, a No. 2 test pipeline, and a No. 3 test pipeline. The water diversion pipeline system includes three inlet and outlet water tank call pipelines. The No. 1 water tank, the No. 2 water tank, and the No. 3 water tank are connected in pairs through the three inlet and outlet water tank call pipelines to form a triangular arrangement. One end of the No. 1 test pipeline, the No. 2 test pipeline, and the No. 3 test pipeline are respectively connected to the No. 1 water tank, the No. 2 water tank, and the No. 3 test pipeline. The other ends of the No. 1 test pipeline, the No. 2 test pipeline, and the No. 3 test pipeline converge at a point to form a T-junction.

[0019] Pool 1 is the inlet pool, and Pools 2 and 3 are outlet pools. Pool 1 is equipped with a sand pump and a steel support for the sand pump. The sand pump is fixed to the steel support and connected to the No. 1 test pipeline, used to pump sand-laden water into the No. 1 test pipeline. The inner walls of Pools 2 and 3 are fixed with steel supports for coarse-particle underwater filters and coarse-particle underwater weighing sensors. The coarse-particle underwater weighing sensors are fixed to their steel supports and connected to a coarse-particle underwater weighing sensor data acquisition instrument. Each of Pools 1, 2, and 3 is equipped with a sand-laden water flow agitator.

[0020] All three test pipes (No. 1, No. 2, and No. 3) are made of transparent plexiglass. Each test pipe includes a control section and an observation section. The control section is the end of each test pipe closest to water tanks 1, 2, and 3, while the observation section is the end of each test pipe furthest from water tanks 1, 2, and 3. The observation section is connected to the control section via flanges with different inclination angles, allowing for different tilt angles between the observation and control sections as needed for the test.

[0021] The control sections of the No. 1, No. 2, and No. 3 test pipelines are each equipped with a test pipeline control valve, an electromagnetic flowmeter, and a coarse particle feeding pipeline. The upper end of the coarse particle feeding pipeline is equipped with a coarse particle feeding port, and the lower end is equipped with a coarse particle control valve for controlling the opening and closing of the coarse particle feeding pipeline.

[0022] The minimum height H of the coarse particle feeding port (10) is determined by formula (1):

[0023]

[0024] In the formula, h t Z1 is the head of the sand pump, Z1 is the height of the water surface in the inlet pool from the bottom of the control section of the No. 1 test pipeline, α is the velocity head correction coefficient, and v max λ is the maximum flow velocity that occurs during the test, g is the acceleration due to gravity, λ is the head loss coefficient along the pipe, L is the distance the water flows from the sand pump along the pipe to the first coarse particle feeding pipe, d is the inner diameter of the test pipe, ζ1 is the local head loss coefficient at the sand pump, ζ2 is the local head loss coefficient at the bend section, ζ3 is the local head loss coefficient at the electromagnetic flowmeter location, ζ4 is the local head loss coefficient at the control valve location of the test pipe, and ζ5 is the local head loss coefficient at the coarse particle feeding pipe location.

[0025] The observation sections of the No. 1, No. 2 and No. 3 test pipelines are set in a closed rectangular glass water tank filled with clean water. Multiple pressure detection holes are evenly distributed on the observation section. A pressure sensor is installed in the pressure detection hole. The side of the pressure sensor is wrapped with a filter screen to prevent mud and sand. The pressure sensor is connected to a pressure sensor signal acquisition instrument.

[0026] The inlet and outlet water tank calling pipeline is equipped with an inlet and outlet water tank calling pipeline control valve; the lower part of the No. 1 test pipeline, No. 2 test pipeline and No. 3 test pipeline is equipped with a movable and telescopic support.

[0027] Preferably, the inclination angle of the flange is between 0° and 90°.

[0028] Preferably, the movable and telescopic bracket includes a telescopic rod, pipe clamps, fixing pins, casters, and caster brakes.

[0029] Preferably, the values ​​are: λ = 0.03, ζ1 = 0.25, ζ2 = 0.30, ζ3 = 0.50, ζ4 = 0.20, ζ5 = 0.20, α = 1.0, L = 4.0m, d = 0.1m, v max =2.5m / s, Z1=1.5m, g=9.81m / s 2 h t =5.0m.

[0030] The hydraulic engineering model of this invention, compared with the prior art, has the following inventive aspects:

[0031] This invention presents, for the first time, a hydraulic model for studying the coarse-particle transport characteristics of sand-laden water flow in a bifurcated pipeline. A sand-laden water flow agitator within the inlet and outlet pools can rapidly mix water and sand of varying proportions to create sand-laden water flows with different sand concentrations. By disassembling the flange and utilizing movable and retractable supports, one end of the device can be easily raised and fixed, forming a pipeline with an overall inclined angle. The detachable sand pumps and coarse-particle underwater weighing sensors within the inlet and outlet pools allow for easy switching between them to accommodate varying experimental conditions with different inlet and outlet flow patterns. A silt filter screen accurately measures the fluid pressure within the pipeline while preventing damage to the pressure sensor from frequent impacts by silt particles. A sealed rectangular glass water tank reduces image distortion caused by the different refractive indices of materials such as plexiglass and water flow, improving the observation accuracy of the high-speed camera. The three sets of inlet and outlet pools can be interconnected via pipes and valves, enabling water circulation and conserving water resources. The experimental device proposed in this invention patent is easy to operate, provides complete and accurate experimental data, can study a wide range of experimental conditions, and saves a lot of manpower and resources. Attached image description:

[0032] Figure 1 This is a side view of the hydraulic model of the present invention;

[0033] Figure 2 This is a top view of the hydraulic engineering model of the present invention;

[0034] Figure 3 This is a top view of the water inlet tank of the present invention;

[0035] Figure 4 This is a cross-sectional view of the water inlet tank AA of the present invention;

[0036] Figure 5 This is a top view of the drainage pool of the present invention;

[0037] Figure 6 This is a cross-sectional view of the drainage tank BB of the present invention;

[0038] Figure 7 This is a front view of the movable and retractable support frame of the present invention;

[0039] Figure 8 This is a side view of the movable and retractable bracket of the present invention;

[0040] Figure 9 This is a side view of the CC section test pipe of the present invention;

[0041] Figure 10 This is a top view of the CC section test pipeline of the present invention;

[0042] Figure 11 This is a side view of the test pipeline of the hydraulic model of the present invention when the bifurcation angle changes;

[0043] Figure 12 This is a top view of the test pipeline of the hydraulic model of the present invention when the bifurcation angle changes;

[0044] Figure 13 This is a side view of the hydraulic model of the present invention when the overall tilt angle is 30°;

[0045] Figure 14 This is a top view of the hydraulic model of the present invention when the overall tilt angle is 30°;

[0046] Figure 15 This is a side view of the hydraulic model of the present invention when the overall tilt angle is 60°;

[0047] Figure 16 This is a top view of the hydraulic model of the present invention when the overall tilt angle is 60°.

[0048] Figure 17 This is a schematic diagram of the experimental data after processing according to the present invention.

[0049] Among them, 1 is water tank No. 1, 2 is water tank No. 2, 3 is water tank No. 3, 4 is the test pipeline control valve, 5 is the electromagnetic flowmeter, 6 is the coarse particle feeding port, 7 is the coarse particle feeding pipeline, 8 is the coarse particle control valve, 9 is the movable and telescopic support, 10 is the flange, 11 is the water flow direction in the pipeline, 12 is the pressure sensor, 13 is the sealed rectangular glass water tank, 14 is test pipeline No. 1, 15 is test pipeline No. 2, 16 is test pipeline No. 3, 17 is the high-speed camera, and 18 is the underwater coarse particle weighing device. Sensor data acquisition instrument, 19 is the inlet and outlet water pool call pipe, 20 is the inlet and outlet water pool call pipe control valve, 21 is the pressure sensor signal acquisition instrument, 22 is the sand pump, 23 is the sand pump steel support, 24 is the pool body, 25 is the sand-containing water flow agitator, 26 is the coarse particle underwater filter screen, 27 is the coarse particle underwater weighing sensor, 28 is the coarse particle underwater weighing sensor steel support, 29 is the telescopic rod, 30 is the pipe clamp, 31 is the fixing pin, 32 is the universal wheel, 33 is the universal wheel brake, and 34 is the anti-mud and sand filter screen. Detailed implementation method:

[0050] The present invention will be described in detail with reference to the accompanying drawings.

[0051] This invention discloses a hydraulic model for studying the coarse particle transport characteristics of sand-laden water flow in a bifurcated pipeline. The model includes an inlet / outlet pool system, a test pipeline system, and a water diversion pipeline system. The inlet / outlet pool system comprises a first pool (1), a second pool (2), and a third pool (3). The test pipeline system comprises a first test pipeline (14), a first test pipeline (15), and a third test pipeline (16). The water diversion pipeline system comprises three inlet / outlet pool access pipelines (19). The first pool (1), the second pool (2), and the third pool (3) are connected in pairs via the three access pipelines (19) to form a triangular arrangement. One end of each of the first test pipelines (14), the first test pipeline (15), and the third test pipeline (16) is connected to the first pool (1), the second pool (2), and the third pool (3), respectively. The other ends of the first test pipelines (14), the first test pipeline (15), and the third test pipeline (16) converge at a single point to form a three-way junction.

[0052] In this embodiment, pool 1 is the inlet pool, and pools 2 and 3 are the outlet pools. Pool 1 is equipped with a sand pump 22 and a sand pump support 23. The sand pump support 23 is fixed to the inner wall of the pool body 24, and the sand pump 22 is fixed to the sand pump support 23 and connected to the No. 1 test pipe 14 to draw sand-laden water into the No. 1 test pipe 14. The inner walls of pools 2 and 3 are equipped with coarse-particle underwater filters 26 and coarse-particle underwater weighing sensor support 28. The coarse-particle underwater weighing sensor 27 is fixed to the coarse-particle underwater weighing sensor support 28 and connected to the coarse-particle underwater weighing sensor data acquisition instrument 18. The pool bodies 24 of pools 1, 2, and 3 are equipped with sand-laden water flow agitators 25 to agitate the mixture of mud and water in the pool bodies 24. When coarse particles flow out with the sand-laden water, they fall onto the coarse particle underwater weighing sensor 27, and the coarse particle underwater weighing sensor data acquisition instrument 18 records the weight information of the coarse particles. The coarse particle underwater filter screen 26 is used to filter coarse particles in the sand-laden water flow, making it easy to recycle and reuse.

[0053] The sand pump 22 and sand pump steel support 23 in pool 1, and the coarse particle underwater weighing sensor data acquisition instrument 18, coarse particle underwater filter 26, coarse particle underwater weighing sensor 27, and coarse particle underwater weighing sensor steel support 28 in pool 2 and pool 3 are all detachable devices, which allows pool 1, pool 2 and pool 3 to be quickly and easily converted into inlet pools or outlet pools.

[0054] The No. 1 test pipe 14, No. 1 test pipe 15 and No. 3 test pipe 16 are made of transparent plexiglass to facilitate observation of the movement of coarse particles inside the pipes.

[0055] The No. 1 test pipe 14, No. 1 test pipe 15, and No. 3 test pipe 16 each include a control section and an observation section. The control section is the end of each of the test pipes 14, 15, and 16 closest to the No. 1 water tank 1, No. 2 water tank 2, and No. 3 water tank 3. The observation section is the end of each of the test pipes 14, 15, and 16 furthest from the No. 1 water tank 1, No. 2 water tank 2, and No. 3 water tank 3. The observation section is connected to the control section via flanges 10 with different inclination angles. Depending on the experimental requirements, different inclination angles can be formed between the observation section and the control section; flanges 10 with various inclination angles ranging from 0° to 90° can be used.

[0056] The control sections of the No. 1 test pipeline 14, No. 1 test pipeline 15 and No. 3 test pipeline 16 are each equipped with a test pipeline control valve 4, an electromagnetic flowmeter 5 and a coarse particle feeding pipeline 7. The upper end of the coarse particle feeding pipeline 7 is equipped with a coarse particle feeding port 6 and the lower end is equipped with a coarse particle control valve 8 for controlling the opening and closing of the coarse particle feeding pipeline 7.

[0057] The coarse particle feeding pipe 7 serves as the channel for coarse particles to enter the test pipe, and is therefore connected to the test pipe. During the test, the coarse particle control valve 8 is fully open. When water is drawn out by the sand pump 22 and flows through the coarse particle feeding pipe 7, a water column of a certain height will appear in the coarse particle feeding pipe 7 because the water in the test pipe is pressurized. Therefore, it is necessary to determine the minimum height of the coarse particle feeding port 6 to prevent water in the test pipe from overflowing from the coarse particle feeding port 6 of the coarse particle feeding pipe 7. The height of the coarse particle feeding port 6 mentioned in this invention refers to the relative height between the top of the coarse particle feeding port 6 and the flow section of the test pipe.

[0058] The present invention determines the minimum height H of the coarse particle feeding port 6 to meet the experimental requirements using the following formula:

[0059]

[0060] In the formula, h t Z1 is the head of the sand pump 22, Z1 is the height of the water surface in the inlet pool from the bottom of the control section of the No. 1 test pipe 14, α is the velocity head correction coefficient, and v max λ represents the maximum flow velocity observed during the experiment, g represents the acceleration due to gravity, λ represents the head loss coefficient along the pipe, L represents the distance the water flows from the sand pump 22 along the pipe to the first coarse particle feeding pipe, d represents the inner diameter of the test pipe, ζ1 represents the local head loss coefficient at the sand pump 22, ζ2 represents the local head loss coefficient at the bend section, ζ3 represents the local head loss coefficient at the location of the electromagnetic flowmeter 5, ζ4 represents the local head loss coefficient at the location of the control valve 4 in the test pipe, and ζ5 represents the local head loss coefficient at the location of the coarse particle feeding pipe 7. Where h... t Z1, v max L and d are obtained based on design and actual measurements, while other parameters are obtained through experiments.

[0061] In this embodiment, based on the preliminary design of the device dimensions, experimental equipment parameters, and experimental flow rate, we know that λ = 0.03, ζ1 = 0.25, ζ2 = 0.30, ζ3 = 0.50, ζ4 = 0.20, ζ5 = 0.20, α = 1.0, L = 4.0m, d = 0.1m, v max =2.5m / s, Z1=1.5m, g=9.81m / s 2 h t=5.0m, which gives H = 2.34m. Therefore, the minimum height H of the coarse particle feeding port 6 is 2.34m; otherwise, water will overflow from the port during the experiment, causing failure. However, if the height of the coarse particle feeding port 6 is designed too high, it will occupy too much space and make feeding difficult. Therefore, in actual operation, after determining the precise value of the height of the coarse particle feeding port 6 using the above formula, the actual height of the coarse particle feeding port 6 is determined to be 2.50m.

[0062] The observation sections of test pipes 14, 15, and 16 are housed in a sealed rectangular glass water tank 13 filled with clean water. This is to reduce image distortion caused by the different refractive indices of materials such as plexiglass and water flow, thereby improving the observation accuracy of the high-speed camera. The high-speed camera 17 is used to capture the movement of coarse particles in the water flow.

[0063] Multiple pressure detection holes are evenly distributed on the observation sections of the No. 1 test pipe 14, No. 15, and No. 3 test pipe 16. Pressure sensors 12 are installed inside each pressure detection hole. The sides of the pressure sensors 12 are wrapped with anti-sediment filter screens 34 to prevent sediment from the water flow from entering the pressure sensors 12, thereby improving measurement accuracy and reducing the probability of damage to the pressure sensors 12. During the test, all pressure sensors 12 are connected to a pressure sensor signal acquisition instrument 21.

[0064] The inlet and outlet water tank calling pipe 19 is equipped with inlet and outlet water tank calling pipe control valves 20. By opening and closing the three sets of inlet and outlet water tank calling pipe control valves 20, water in the No. 1 water tank 1, No. 2 water tank 2 and No. 3 water tank 3 can be called back and forth.

[0065] The lower part of the No. 1 test pipe 14, No. 1 test pipe 15, and No. 3 test pipe 16 is equipped with a movable and telescopic support 9. The movable and telescopic support 9 includes a telescopic rod 29, pipe clamps 30, fixing pins 31, casters 32, and caster brakes 33. The telescopic rod 29 is used to raise and lower the height of the pipe clamps 30. Each section of the rod has multiple holes; the fixing pins 31 are passed through these holes to fix the height. The pipe clamps 30 have an opening and closing design; opening the pipe clamps 30 allows for easy installation and locking of the three sets of test pipes. The casters 32 allow the entire support to move flexibly. The caster brakes 33 brake the casters, ensuring the entire support will not shift after being placed in a fixed position.

[0066] The coarse particle sizes used in the experiments of this invention were 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, and 20mm, and the test flow velocities were 1.0m / s, 1.5m / s, 2.0m / s, and 2.5m / s. The following detailed embodiments further illustrate the implementation method of this invention for a hydraulic model to study the coarse particle transport characteristics of sand-laden water flow in a bifurcated pipeline.

[0067] Example 1:

[0068] The test conditions were set as follows: the sediment content of the water flow was 0, i.e., clear water; the angle between test pipes 14, 15, and 16 was 120°; the inclination angle of test pipe 14 was 0°; and the flow pattern was one inlet and two outlets, i.e., test pipe 14 was the inlet pipe, and test pipes 15 and 16 were the outlet pipes. The specific test steps are as follows:

[0069] Step A1: Install and debug the hydraulic model of the present invention for studying the coarse particle transport characteristics of sand-laden water flow in bifurcated pipelines;

[0070] Step A2: Check if there is enough water in pool 1. If not, open the inlet / outlet water tank to call the pipeline control valve 20 to transfer the excess water from pool 2 and / or pool 3 into pool 1.

[0071] Step A3: Connect the pressure sensor 12 and the coarse particle underwater weighing sensor 27 to the pressure sensor signal acquisition instrument 21 and the coarse particle underwater weighing sensor data acquisition instrument 18 respectively, set the parameters of the pressure sensor 12 and the coarse particle underwater weighing sensor 27, and zero the pressure.

[0072] Step A4: Set up the high-speed camera 17 in front of the sealed rectangular glass water tank 13 to film the movement of coarse particles in the clear water.

[0073] Step A5: Turn on the sand pump 22 and fully open the test pipe control valves 4 on test pipe 15 and test pipe 3 16. Adjust the opening of the test pipe control valve 4 on test pipe 14: First, make a coarse adjustment. When the flow rate displayed on the electromagnetic flowmeter 5 reaches near the target flow rate, make a fine adjustment until the target flow rate is reached and the flow rate no longer fluctuates. The adjustment is then complete.

[0074] Step A6: Turn on the underwater coarse particle weighing sensor data acquisition instrument 18 and the pressure sensor signal acquisition instrument 21. Open the coarse particle control valve 8 on the first test pipe 14, and close the coarse particle control valves 8 on the first test pipe 15 and the third test pipe 16. Pour a fixed amount of coarse particles evenly into the coarse particle feeding port 6 on the first test pipe 14. Turn on the high-speed camera 17 and use a stopwatch to time the process. Record the time when the coarse particles just enter the first test pipe 14 and record the time when they completely leave the first test pipe 15 and the third test pipe 16.

[0075] Step A7: When the coarse particles have completely flowed out of test pipe 15 and test pipe 3, turn off the high-speed camera 17, the coarse particle underwater weighing sensor data acquisition instrument 18, the pressure sensor signal acquisition instrument 21, and the sand pump 22. After the clean water in the three test pipes has completely flowed out, close the control valves 4 of the three test pipes.

[0076] Step A8: Export the test data and retrieve the coarse particles filtered out of the coarse particle underwater filter 26 for recycling.

[0077] Step A9: Process the exported experimental data:

[0078] During the experiment, the measured instantaneous pressure p collected by the pressure sensor was converted into the time-averaged pressure. It consists of two parts: the measured instantaneous pressure p' and the pulsating pressure p'. The average of the measured instantaneous pressure p is the time-averaged pressure. Subtract the time-averaged pressure from the measured instantaneous pressure p The pulsating pressure p' can be obtained. Its expression is:

[0079]

[0080] The measured pulsating pressure p′ is divided into several sub-intervals. The frequency of pulsating pressure occurrences in each sub-interval and its proportion in the whole are calculated. A Gaussian distribution function is used for fitting, resulting in the following fitting formula:

[0081]

[0082] In the formula: f(p) is the probability density function; μ is the expected value of the fluctuating pressure; σ is the variance of the fluctuating pressure. μ is the location parameter of the probability density fitting function, which determines the location of the distribution function. σ is the shape parameter of the probability density fitting function, which determines the degree of dispersion of the distribution function. The larger σ is, the more dispersed the data distribution; the smaller σ is, the more concentrated the data distribution.

[0083] To process the pulsating pressure signal caused by the motion of coarse particles in a pipeline, a Fast Fourier Transform (FFT) method is employed. By converting the time-domain signal of the pulsating pressure into the frequency-domain signal, the amplitude spectral density function, phase spectral density function, and power spectral density function of the pulsating pressure are obtained. These functions together constitute the spectral density distribution of the pulsating pressure in the coarse-particle pipeline. The expression for the Fourier transform of the non-periodic continuous-time signal f(t) is:

[0084]

[0085]

[0086] Figure 17 A is a diagram showing the pulsating pressure distribution generated when coarse particles with a diameter of 12 mm enter a test pipeline with a test flow rate of 1 m / s at a sand transport rate of 0.208 kg / s. Figure 17 B is the time-averaged pressure distribution at different test points when coarse particles with a diameter of 12 mm enter the test pipeline with a test flow rate of 1 m / s under the condition of a sand transport rate of 0.208 kg / s. Figure 17 C is the frequency histogram generated when coarse particles with a diameter of 12 mm enter a test pipeline with a test flow rate of 1 m / s at a sand transport rate of 0.208 kg / s. Figure 17 D is the power spectrum of a coarse particle with a diameter of 12 mm entering a test pipeline with a test flow rate of 1 m / s at a sand transport rate of 0.208 kg / s.

[0087] Example 2:

[0088] The test conditions were set as follows: the sediment concentration of the sediment-laden water flow was 50 kg / m³. 3 The included angle between test pipes 14, 15, and 16 is 120°, and the inclination angle of test pipe 14 is 0°. The flow pattern is one inlet and two outlets, meaning test pipe 14 is the inlet pipe, and test pipes 15 and 16 are the outlet pipes. The specific test steps are as follows:

[0089] Step B1 is the same as step A1.

[0090] Step B2 is the same as step A2.

[0091] Step B3, the formula for calculating sediment content is:

[0092]

[0093] In the formula, S refers to the sediment content of the sediment-laden water flow, m refers to the total mass of sediment added, and ρ s V refers to the density of the sediment used in the experiment, and V refers to the volume of water.

[0094] The density of the sediment used in the experiment was 2650 kg / m³. 3 The pre-filled water volume in pool 1 is 2m³. 3 According to the above formula, adding 101.92 kg of sand to pool 1 and turning on the sand-containing water agitator 25 will produce a sand content of 50 kg / m³. 3 The sediment-laden water flow.

[0095] Step B4 is the same as step A3.

[0096] Step B5: Because the sandy water flow is turbid, the high-speed camera 17 cannot capture the movement of coarse particles, so it is removed.

[0097] Step B6 is the same as step A5.

[0098] Step B7: Turn on the underwater coarse particle weighing sensor data acquisition instrument 18 and the pressure sensor signal acquisition instrument 21. Open the coarse particle control valve 8 on the first test pipe 14, and close the coarse particle control valves 8 on the first test pipe 15 and the third test pipe 16. Pour a fixed amount of coarse particles evenly into the coarse particle feeding port 6 on the first test pipe 14. At the same time, use a stopwatch to record the time when the coarse particles just enter the first test pipe 14 and when they completely leave the first test pipe 15 and the third test pipe 16.

[0099] Step B8: When the coarse particles have completely flowed out of test pipe 15 and test pipe 16, shut down the underwater coarse particle weighing sensor data acquisition instrument 18, the pressure sensor signal acquisition instrument 21, and the sand pump 22. After the sand-containing water in the test pipes has completely flowed out, close the control valves of the three test pipes.

[0100] Step B9 is the same as step A8.

[0101] Step B10 is the same as step A9.

[0102] Example 3:

[0103] The test conditions were set as follows: the sediment concentration of the sediment-laden water flow was 50 kg / m³. 3 The included angle between test pipes 14, 15, and 16 is 180°, and the inclination angle of test pipe 14 is 0°. The flow pattern is one inlet and two outlets, meaning test pipe 14 is the inlet pipe, and test pipes 15 and 16 are the outlet pipes. The specific test steps are as follows:

[0104] Step C1: Remove the original test pipes 15 (first test pipe) and 16 (third test pipe) with an angle not exceeding 180°. Then, move the movable and telescopic support 9 to a suitable position, adjust the direction of the pipe clamps 30, open the pipe clamps 30, and fix the test pipes 15 (first test pipe) and 16 (third test pipe) with an angle of 180° using the pipe clamps 30. Install and fix the connection position using the flange 10. The assembly of the test pipes with a branching angle of 180° is now complete.

[0105] Step C2 is the same as step A1.

[0106] Step C3 is the same as step A2.

[0107] Step C4 is the same as step B3.

[0108] Step C5 is the same as step A3.

[0109] Step C6 is the same as step B5.

[0110] Step C7 is the same as step A5.

[0111] Step C8 is the same as step B7.

[0112] Step C9 is the same as step B8.

[0113] Step C10 is the same as step A8.

[0114] Step C11 is the same as step A9.

[0115] Example 4:

[0116] The test conditions were set as follows: the sediment concentration of the sediment-laden water flow was 50 kg / m³. 3 The included angle between test pipes 14, 15, and 16 is 180°. Test pipe 14 has an inclination angle of 30°. The flow pattern is one inlet and two outlets, meaning test pipe 14 is the inlet pipe, and test pipes 15 and 16 are the outlet pipes. The specific test steps are as follows:

[0117] Step D1: Disassemble the pipe fittings. Use the telescopic rod 29 to raise the height of the pipe clamp 30. Once the target height is reached, pass the fixing pin 31 through the hole to secure it. Adjust the direction of the pipe clamp 30, open the pipe clamp 30, and fix the target test pipe with the pipe clamp 30. Install and fix the connection position with the flange 10. The test device with an overall tilt angle of 30° is now assembled.

[0118] Step D2 is the same as step A1.

[0119] Step D3 is the same as step A2.

[0120] Step D4 is the same as step B3.

[0121] Step D5 is the same as step A3.

[0122] Step D6 is the same as step B5.

[0123] Step D7 is the same as step A5.

[0124] Step D8 is the same as step B7.

[0125] Step D9 is the same as step B8.

[0126] Step D10 is the same as step A8.

[0127] Step D11 is the same as step A9.

[0128] Example 5:

[0129] The test conditions were set as follows: the sediment concentration of the sediment-laden water flow was 50 kg / m³. 3 The included angle between test pipes 14, 15, and 16 is 180°. Test pipe 14 has an inclination angle of 60°. The flow pattern is two inlets and one outlet, meaning test pipes 14 and 15 are inlet pipes, and test pipe 16 is the outlet pipe. The specific test steps are as follows:

[0130] Step E1: Disassemble the pipe fittings. Use the telescopic rod 29 to raise the height of the pipe clamp 30. Once the target height is reached, pass the fixing pin 31 through the hole to secure it. Adjust the direction of the pipe clamp 30, open the pipe clamp 30, and fix the target test pipe with the pipe clamp 30. Install and fix the connection position with the flange 10. The test device with an overall tilt angle of 60° is now assembled.

[0131] Step E2: Set pool 1 and pool 2 as inlet pools.

[0132] Step E3: Check whether there is sufficient water in pool 1 and pool 2. If the water is insufficient or excessive, the water in the three pool systems will be transferred to each other through the three sets of inlet and outlet water pipes 19 until the water volume in pool 1 and pool 2 meets the test requirements.

[0133] Step E4: Add a certain amount of sand to pool 1 and pool 2, turn on the sand-containing water flow agitator 25, and stir to form a sand-containing water flow with a sand content of 50 kg / m3.

[0134] Step E5 is the same as step A3.

[0135] Step E6 is the same as step B5.

[0136] Step E7: Turn on the sand pump 22, fully open the test pipeline control valve 4 on test pipeline 3 16, and adjust the opening of the test pipeline control valves 4 on test pipeline 14 and 15. First, perform a coarse adjustment. When the flow values ​​displayed by electromagnetic flowmeter 5 and electromagnetic flowmeter 8 reach near the target flow rate, then perform a fine adjustment until the target flow rate is reached and the flow value no longer fluctuates. The adjustment is then complete.

[0137] Step E8: Turn on the underwater coarse particle weighing sensor data acquisition instrument 18 and the pressure sensor signal acquisition instrument 21. Open the coarse particle control valve 8 on test pipe 14 and test pipe 15, and close the coarse particle control valve 16 on test pipe 3. Pour a fixed amount of coarse particles evenly into the coarse particle feeding port 6 on test pipe 14 and test pipe 15. Simultaneously, use a stopwatch to record the time when the coarse particles just enter test pipe 14 and test pipe 15, and record the time when they completely leave test pipe 3.

[0138] Step E9: When the coarse particles have completely flowed out of the No. 3 test pipe 16, turn off the coarse particle underwater weighing sensor data acquisition instrument 18, the pressure sensor signal acquisition instrument 21, and the sand pump 22. After the sand-containing water in the test pipe has completely flowed out, close the control valves of the three test pipes.

[0139] Step E10 is the same as step A8.

[0140] Step E11 is the same as step A9.

Claims

1. A hydraulic model for studying the coarse-particle transport characteristics of sand-laden water flow in a bifurcated pipeline, characterized in that, The system includes an inlet and outlet water tank system, a test pipeline system, and a water diversion pipeline system. The inlet and outlet water tank system includes a No. 1 water tank (1), a No. 2 water tank (2), and a No. 3 water tank (3). The test pipeline system includes a No. 1 test pipeline (14), a No. 2 test pipeline (15), and a No. 3 test pipeline (16). The water diversion pipeline system includes three inlet and outlet water tank calling pipelines (19). The No. 1 water tank (1), the No. 2 water tank (2), and the No. 3 water tank (3) are connected in pairs through the three inlet and outlet water tank calling pipelines (19) to form a triangular arrangement. One end of the No. 1 test pipeline (14), the No. 2 test pipeline (15), and the No. 3 test pipeline (16) is connected to the No. 1 water tank (1), the No. 2 water tank (2), and the No. 3 water tank (3) respectively. The other ends of the No. 1 test pipeline (14), the No. 2 test pipeline (15), and the No. 3 test pipeline (16) converge at one point to form a three-way pipeline. The No. 1 water tank (1) is the inlet tank, and the No. 2 water tank (2) and the No. 3 water tank (3) are the outlet tanks; the No. 1 water tank (1) is equipped with a sand pump (22) and a sand pump steel support (23). The sand pump (22) is fixed on the sand pump steel support (23) and connected to the No. 1 test pipeline (14) to pump sand-laden water into the No. 1 test pipeline (14); the No. 2 water tank (2) and the No. 3 water tank (3) are... The inner wall of the body (24) is fixedly provided with a coarse particle underwater filter screen (26) and a coarse particle underwater weighing sensor steel bracket (28). The coarse particle underwater weighing sensor (27) is fixed on the coarse particle underwater weighing sensor steel bracket (28) and connected to the coarse particle underwater weighing sensor data acquisition instrument (18). The pool bodies (24) of the No. 1 pool (1), No. 2 pool (2) and No. 3 pool (3) are all provided with sand-containing water flow agitators (25). The No. 1 test pipe (14), No. 2 test pipe (15), and No. 3 test pipe (16) are all made of transparent plexiglass. Each of the No. 1 test pipe (14), No. 2 test pipe (15), and No. 3 test pipe (16) includes a control section and an observation section. The control section is the end of the No. 1 test pipe (14), No. 2 test pipe (15), and No. 3 test pipe (16) that is close to the No. 1 water tank (1), No. 2 water tank (2), and No. 3 water tank (3). The observation section is the end of the No. 1 test pipe (14), No. 2 test pipe (15), and No. 3 test pipe (16) that is away from the No. 1 water tank (1), No. 2 water tank (2), and No. 3 water tank (3). The observation section is connected to the control section through flanges (10) with different inclination angles. According to the test requirements, different inclination angles are formed between the observation section and the control section. The control sections of the No. 1 test pipeline (14), the No. 2 test pipeline (15), and the No. 3 test pipeline (16) are all equipped with test pipeline control valves (4), electromagnetic flowmeters (5), and coarse particle feeding pipelines (7). The upper end of the coarse particle feeding pipeline (7) is equipped with a coarse particle feeding port (6), and the lower end is equipped with a coarse particle control valve (8) for controlling the opening and closing of the coarse particle feeding pipeline (7). The minimum height H of the coarse particle feeding port (6) is determined by formula (1): In the formula, h t Z1 is the head of the sand pump (22), Z1 is the height of the water surface in the inlet pool from the bottom of the control section of the No. 1 test pipe (14), α is the velocity head correction coefficient, and v max λ is the maximum flow velocity that occurs during the test, g is the gravitational acceleration, λ is the friction head loss coefficient, L is the distance of water flow from the sand pump (22) along the pipeline to the first coarse particle feeding pipeline, d is the inner diameter of the test pipeline, ζ1 is the local head loss coefficient at the sand pump (22), ζ2 is the local head loss coefficient at the bend section, ζ3 is the local head loss coefficient at the electromagnetic flowmeter (5), ζ4 is the local head loss coefficient at the control valve (4) of the test pipeline, and ζ5 is the local head loss coefficient at the coarse particle feeding pipeline (7). The observation sections of the No. 1 test pipe (14), No. 2 test pipe (15) and No. 3 test pipe (16) are set in a closed rectangular glass water tank (13) filled with clean water. Multiple pressure detection holes are evenly distributed on the observation section. Pressure sensors (12) are installed in the pressure detection holes. The side of the pressure sensor (12) is wrapped with a mud and sand filter screen (34). The pressure sensors (12) are all connected to the pressure sensor signal acquisition instrument (21). The inlet and outlet water tank calling pipe (19) is equipped with an inlet and outlet water tank calling pipe control valve (20); the lower part of the No. 1 test pipe (14), No. 2 test pipe (15) and No. 3 test pipe (16) is equipped with a movable and telescopic support (9).

2. A hydraulic model for studying the coarse-particle transport characteristics of sand-laden water flow in a bifurcated pipeline, as described in claim 1, is characterized in that... The inclination angle of the flange (10) is preferably between 0° and 90°.

3. A hydraulic model for studying the coarse-particle transport characteristics of sand-laden water flow in a bifurcated pipeline, as described in claim 1, is characterized in that... The movable and telescopic bracket (9) includes a telescopic rod (29), a pipe clamp (30), a fixing pin (31), a caster wheel (32), and a caster wheel brake (33).

4. A hydraulic model for studying the coarse-particle transport characteristics of sand-laden water flow in a bifurcated pipeline, as described in claim 1, is characterized in that... Preferably, the values ​​are: λ = 0.03, ζ1 = 0.25, ζ2 = 0.30, ζ3 = 0.50, ζ4 = 0.20, ζ5 = 0.20, α = 1.0, L = 4.0m, d = 0.1m, v max =2.5m / s, Z1=1.5m, g=9.81m / s 2 h t =5.0m.

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