An experimental device and experimental method for simulating the transport of pollutants from ships in the hyporheic zone

Abstract

The invention discloses an experimental device and an experimental method for simulating the transport of pollutants from ships in a hyporheic zone, comprising a simulated river flume divided from left to right into an upstream river area, a ship-traveling river simulation area and a downstream river area, a ship model sailing in the ship-traveling river simulation area, a ship travel control system arranged above the simulated river flume and used to drive the ship model to simulate the opposite travel of dual-channel ships, a water level control system respectively connected to the upstream river area and the downstream river area and used to control the upstream and downstream water levels of the simulated river during the experiment, a pollutant simulation system for simulating the discharge of pollutants on the ship model, a pollutant monitoring system for monitoring the temporal and spatial variation of pollutants in the river overlying water and hyporheic zone under different ship pollutant discharge conditions, and a camera system for photographing the tracer process of ship pollutants in the simulated river and hyporheic zone. The invention can conduct experiments on the entry, transport and release of ship pollutants in the hyporheic zone.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy engineering, in particular to an experimental device and an experimental method for simulating the migration of pollutants from ships in an undercurrent zone. Background Art

[0002] The hyporheic zone is a crucial component of river ecosystems. Ship pollutants entering the overlying water migrate and accumulate in the hyporheic zone due to hyporheic exchange, significantly impacting the water quality, pore water flow paths, and benthic organism survival within the hyporheic zone. High pollutant discharge concentrations can even cause the hyporheic zone and river to lose their self-regulating functions. Therefore, studying the entry, migration, and release characteristics of ship pollutants in the hyporheic zone is crucial for accurately understanding the spatial and temporal distribution of pollutants in the overlying water, water-sediment interface, and hyporheic zone under the influence of ship pollution, as well as the mechanisms of their impact, and for proposing practical and feasible remediation strategies.

[0003] Uncovering the transport of ship pollutants in the overlying water and hyporheic zone of rivers is not only a key to scientifically addressing hyporheic zone pollution, but also provides strong theoretical support for controlling surface and subsurface pollutants in rivers under the influence of ship pollutants. Common research methods for studying the transport mechanisms of ship pollutants in the hyporheic zone include field monitoring and numerical simulation. Field observations primarily involve the placement of tracers upstream or at the discharge section of a ship, sampling overlying water and sediment at regular intervals at downstream sections, and conducting hydrochemical analysis to determine the spatiotemporal distribution of pollutants in the overlying water and hyporheic zone after they enter the river. Numerical simulations generalize the hydrogeological conditions of the overlying water and hyporheic zone. Based on the overlying water k-ω equation, Darcy's law, and pollutant transport equations, numerical simulation software such as Fluent and COMSOL are used to construct numerical models and analyze the transport pathways of pollutants in the hyporheic zone. Field observations require significant human and material resources and cannot provide long-term continuous monitoring, making it difficult to characterize the spatiotemporal distribution of ship pollutants in the hyporheic zone. However, numerical simulations generally ignore the impact of ship pollutant concentration gradients in the overlying water on hyporheic exchange. Furthermore, due to the influence of hydrogeological generalization, grid discretization methods, and iterative algorithms, they can only provide approximate numerical solutions to the migration process of ship pollutants in the hyporheic zone.

[0004] Indoor experiments are also an important tool for studying the ingress, migration, and release of ship pollutants in the hyporheic zone. However, current experimental setups primarily focus on the impact of ship waves on the spatiotemporal distribution of sediment pollutants and the spatiotemporal distribution of pollutants in the hyporheic zone under the influence of hydrodynamic forces and gates. The lack of indoor simulation and monitoring equipment for ship pollutant leakage makes it difficult to directly observe the occurrence and concentration of pollutants in the hyporheic zone under different ship pollutant exposure conditions, making it impossible to conduct experiments on the ingress, migration, and release of ship pollutants in the hyporheic zone.

[0005] Therefore, the above problems need to be solved urgently. Summary of the Invention

[0006] Purpose of the invention: The first purpose of the present invention is to provide an experimental device for simulating the migration of ship pollutants in the hyporheic zone, which can not only qualitatively observe the tracing characteristics of the migration of various ship pollutants in the hyporheic zone under the influence of different river water level gradients, ship pollutant emission rates, ship drafts and ship navigation speeds, but also quantitatively evaluate the temporal and spatial variation patterns of pollutant concentrations at characteristic positions in the hyporheic zone, and establish a response relationship between ship operation characteristics, pollutant emission characteristics and the migration process of pollutants in the hyporheic zone.

[0007] The second object of the present invention is to provide an experimental method for an experimental device simulating the migration of ship pollutants in the hyporheic zone.

[0008] Technical solution: To achieve the above objectives, the present invention discloses an experimental device for simulating the migration of ship pollutants in the hyporheic zone, comprising a simulated river flume divided from left to right into an upstream river area, a ship-traveling river simulation area and a downstream river area, a ship model sailing in the ship-traveling river simulation area, a ship control system arranged above the simulated river flume and used to drive the ship model to simulate the opposite travel of dual-channel ships, a water level control system connected to the upstream river area and the downstream river area respectively and used to control the upstream and downstream water levels of the simulated river during the experiment, a pollutant simulation system connected to the ship model and used to simulate the discharge of pollutants on the ship model, a pollutant monitoring system used to monitor the spatiotemporal variation of pollutants in the river overlying water and the hyporheic zone under different ship pollutant discharge conditions, and a camera system used to capture the ship pollutant tracing process in the simulated river and the hyporheic zone.

[0009] Among them, the simulated river water tank is a waterproof box-type structure with an open top, wherein the front of the simulated river water tank is a transparent plate. A partition plate for separating areas and a first water inlet and outlet connected to the water level control system are provided in the simulated river water tank. The partition plate is an acrylic plate with water-permeable holes evenly distributed on the upper part, and the outer periphery of the acrylic plate is covered with gauze.

[0010] Preferably, the upstream area of ​​the river simulates the upstream boundary of the river with a constant water head, the ship-passing river simulation area simulates the overlying water and the undercurrent zone of the ship-passing river, the undercurrent zone of the ship-passing river simulation area is composed of filled white quartz sand, and the downstream area of ​​the river simulates the downstream boundary of the river with a constant water head. The water in the upstream area of ​​the river flows to the ship-passing river simulation area through the water-permeable holes of the dividing plate, and the water in the ship-passing river simulation area flows to the downstream area of ​​the river through the water-permeable holes of the dividing plate.

[0011] Furthermore, the ship control system includes support plates symmetrically fixed on the top of the two side plates of the simulated river flume, two sets of waterways arranged in parallel above the simulated river flume and located between the two support plates, the waterway includes a reduction motor located on the inner side of one support plate, a driving guide wheel connected to the output shaft of the reduction motor, a support located on the inner side of the other support plate, a driven guide wheel located on the support, a chain wound around the driving guide wheel and the driven guide wheel, and an adjustable voltage-stabilized power supply located on the support plate and connected to the reduction motor through wires.

[0012] Furthermore, the ship model includes a hull, a beam fixed on the inner wall of the hull, connecting longitudinal rods symmetrically arranged vertically on the beams, connecting cross rods located at the ends of the two connecting longitudinal rods, a telescopic longitudinal rod connected to the connecting cross rod and capable of being extended and retracted up and down, and a connector connected to the telescopic longitudinal rod and used to be clamped on the ship control system, the telescopic longitudinal rod includes an inner sleeve, two hemispheres located at the top of the inner sleeve and symmetrically arranged, a first spring located in the inner sleeve and connected to the hemispheres on both sides at both ends, an outer sleeve mounted on the upper end of the inner sleeve, and circular holes evenly spaced on the outer sleeve and used to adapt to the hemispheres; the connector includes a hollow cuboid fixed on the top of the outer sleeve, telescopic plates located at the two ends of the hollow cuboid, and a second spring located in the hollow cuboid and connected to the telescopic plates at both ends.

[0013] Preferably, the water level control system includes a first water tank for storing simulated river water required for the experiment, a first submersible pump located in the first water tank, a working platform located on the ground, and a second water tank located on the working platform and used to simulate stable water levels upstream and downstream of the river through an overflow effect, a bottom water inlet located at the bottom of the second water tank and connected to the first submersible pump through a first water pipe, a bottom water outlet located at the bottom of the second water tank and connected to the first water tank through the first water pipe, a second water inlet and outlet located on the side of the second water tank, a control valve arranged on the second water inlet and outlet, a first overflow plate vertically arranged at the middle position of the bottom of the inner wall of the second water tank, a permeable plate vertically arranged at the bottom of the inner wall of the second water tank and spaced a certain distance from the first overflow plate to form a sliding groove, a second overflow plate located in the sliding groove and movable up and down along the sliding groove, a steel wire rope fixed at one end to the top of the second overflow plate, a buckle fixed to the top of the second water tank and used to pass the steel wire rope, and a second water pipe connected to the second water inlet and outlet.

[0014] Furthermore, the pollutant simulation system includes a first standard solution tank filled with a simulated organic pollutant solution, a second standard solution tank filled with a simulated nutrient-rich domestic sewage of a ship, a third standard solution tank filled with a simulated variable-density chemical pollutant of a ship, a first peristaltic pump connected to the first standard solution tank through a transparent hose, a second peristaltic pump connected to the second standard solution tank through a transparent hose, a third peristaltic pump connected to the third standard solution tank through a transparent hose, a four-way joint connected to the first peristaltic pump, the second peristaltic pump and the third peristaltic pump, and a pollutant discharge pipe connected to the four-way joint through a transparent hose and evenly distributed on the ship model.

[0015] Furthermore, the pollutant monitoring system includes sampling holes distributed on the back of the simulated river water tank, an integrated sensor located in the simulated river water tank and used to monitor the change data of ship organic pollutants, domestic pollutants and variable density chemical pollutants in the hyporheic zone, a data processor connected to the integrated sensor, and a display, wherein the integrated sensor includes a COD probe, an ammonia nitrogen probe and a conductivity probe.

[0016] Preferably, the camera system includes a camera located in front of the simulated river flume, a computer connected to the camera, a light-shielding curtain surrounding the camera and the simulated flume, and a lighting panel located just above the simulated flume.

[0017] The present invention discloses an experimental method for an experimental device simulating the migration of pollutants from ships in a hyporheic zone, comprising the following steps:

[0018] (1) Prepare ship pollutant solutions. The simulated organic pollutant solution is prepared by mixing deionized water and methylene blue MB and placing it in the first standard solution tank. The simulated nutrient-rich domestic sewage of the ship is prepared by mixing deionized water, analytical grade ammonium chloride NH4Cl and brilliant blue BB dye and placing it in the second standard solution tank. The simulated variable density chemical pollutants of the ship are prepared by mixing deionized water, industrial salt NaCl and edible allure red AR dye and placing it in the third standard solution tank for standby use. The three types of pollutants in the three standard solution tanks are prepared by methylene blue MB, brilliant blue BB and edible allure red AR dye to distinguish the migration process of the three types of pollutants.

[0019] (2) Arrange a simulated river and riverbed, close all the control valves on the sides of the second water tank on the left and right sides of the simulated river flume, add deionized water to the first water tank, adjust the position of the second overflow plate in the second water tank by pulling the wire rope upward, and when the elevation of the top of the second overflow plate reaches the preset position of the experiment, tie the wire rope and fix it on the buckle to ensure that the second overflow plate is fixed in the sliding groove between the first overflow plate and the permeable plate, turn on the first submersible pump to supply water to the water inlet at the bottom of the second water tank through the first water pipe, and observe whether the excess deionized water flows over the second overflow plate to the second water tank after the water enters the second water tank. The water is discharged from the water outlet at the bottom of the tank and returns to the first water tank through the first water pipe. The water level upstream and downstream of the simulated river can be adjusted by adjusting the position of the second overflow plate. After screening the quartz sand, it is washed multiple times with deionized water. The washed quartz sand is placed in a bucket by saturating it with water. The washed quartz sand is laid layer by layer in the simulated river water tank by saturating it with water. After each layer of quartz sand is laid along the simulated river water tank, the back of the simulated river water tank is tapped to ensure that bubbles in the hyporheic zone are removed. When laying the riverbed and hyporheic zone, the water level in the simulated river water tank is always higher than a certain height of the filled quartz sand.

[0020] (3) Arrange the camera and the integrated sensor, set up the camera at a certain distance in front of the simulated river flume, adjust the camera parameters, connect the camera to the computer, control the camera's shooting time and frequency, and ensure that the migration process of ship pollutants during the experiment is recorded; calibrate the COD probe, ammonia nitrogen probe, and conductivity probe in the integrated sensor with COD, ammonia nitrogen, and salinity standard solutions and connect them to the data processor. During the sand filling process, place the integrated sensor at a preset position on the back of the simulated river flume;

[0021] (4) Adjust the ship navigation parameters, compress the telescopic plate of the connector of the ship model and place it on the chain, loosen the telescopic plate after it is placed stably to ensure that the connector and the corresponding ship model can move at the same speed as the chain, and connect the four-way connector in the pollutant simulation system to the top of the pollutant discharge pipe at the front, middle or rear of the hull through a transparent hose according to the experimental requirements, so as to simulate the impact of pollutants discharged at the front, middle or rear of the hull on the undercurrent zone during the navigation of the ship; by controlling the contraction and relaxation of the hemisphere at the top of the inner sleeve in the telescopic longitudinal rod so that the hemisphere is located on the circular hole at different positions of the outer sleeve, the relative position of the inner sleeve and the outer sleeve can be adjusted to change the total length of the telescopic longitudinal rod. Since the chain height remains unchanged, the draft of the ship can be adjusted by adjusting the length of the telescopic longitudinal rod; by adjusting the voltage of the adjustable voltage stabilizer, the rotation speed of the reduction motor is controlled to adjust the running speed of the ship; by placing the ship model on two parallel channels, the impact of the dual-channel ship traveling in opposite directions on the pollutant emission is simulated; by adjusting the reversal of the adjustable voltage stabilizer, the impact of the ship pollutant emission in different navigation directions is simulated;

[0022] (5) Run the experiment, open the control valves on the side of the second water tank on the left and right sides of the simulated river flume, so that the left and right water heads enter the simulated river and the undercurrent zone. Due to the different water heads on the left and right sides of the simulated river flume, a water head difference between the upstream and downstream of the river and the surface water flow rate are generated; turn on the adjustable voltage-stabilized power supply to make the reduction motors on the support plates on the left and right sides of the simulated river flume drive the active guide wheels to rotate, thereby driving the chains of the two channels to operate stably in a cycle, ensuring that the ship sails at a preset speed on the free surface of the simulated river; turn on and adjust the flow rates of the first peristaltic pump, the second peristaltic pump and the third peristaltic pump respectively, so that the methylene blue During the ship's voyage, bright blue organic pollutants, bright blue domestic pollutants, and bright red variable-density pollutants were discharged into the simulated river and hyporheic zone at different rates. During the experiment, a microsampler was used to extract the simulated river overlying water and hyporheic zone pore water through the sampling hole on the back of the simulated river flume. The integrated sensor recorded the changes in the ship's organic pollutants, domestic pollutants, and variable-density chemical pollutants in real time during the ship's voyage. The camera was used to take timed photos and the migration process of the three ship pollutants in the river overlying water and hyporheic zone was recorded on the computer. In each group of experiments, the three pollutants were not released at the same time.

[0023] (6) Stop the experiment and data analysis. When the ship pollutants have completely entered the hyporheic zone and the corresponding pollutants no longer change shape, the experiment is terminated. Turn off all system power supplies, remove the experimental sand and wash it with deionized water, and then repeat the next set of experiments according to the above steps; organize high-definition photos at different times during the ship's navigation process, and qualitatively observe the tracing characteristics of various ship pollutants migrating in the hyporheic zone under the influence of different river water level gradients, ship pollutant emission rates, ship pollutant emission durations, ship drafts, and ship navigation speeds; by analyzing the in-situ data of the concentration changes of three types of ship pollutants at different locations, quantitatively evaluate the response relationship between ship operation characteristics, pollutant emission characteristics, and the migration process of pollutants in the hyporheic zone;

[0024] The total volume V of the hyporheic zone in the sand slope at the bottom of the river is calculated by hp As the control body, the following formula is fitted to describe the mathematical relationship between the change of pollutant concentration in the hyporheic zone and the characteristics of ship pollutant discharge, ship operation characteristics, and upstream and downstream water levels of the river:

[0025]

[0026] The average concentration of pollutants monitored by sampling holes and integrated sensors in the hyporheic zone is C hp,i In the formula, the subscript i represents the concentration of the i-th pollutant, i=1, 2, 3 represent ship organic pollutants, domestic pollutants and variable density chemical pollutants respectively, and the organic pollutant concentration of the first standard solution tank is C point1 , the concentration of domestic pollutants in the second standard solution tank is C point2, the variable density pollutant concentration in the third standard solution tank is C point3 , the flow rate of the first peristaltic pump is Q point1 , the flow rate of the second peristaltic pump is Q point2 , the flow rate of the third peristaltic pump is Q point3 , the undercurrent flow rate is Q out .

[0027] Beneficial effects: Compared with the existing technology, the present invention has the following significant advantages: (1) The present invention can intuitively simulate and characterize the migration process of ship pollutants in the overlying water and hyporheic zone of the river; (2) The pollutant monitoring system of the present invention can automatically record in real time the spatiotemporal variation data of chemical oxygen demand (COD), ammonia nitrogen and conductivity in the overlying water and hyporheic zone of the river during the discharge of ship pollutants, saving labor costs while increasing the reliability of the data results; (3) The present invention can accurately set the stable water head upstream and downstream of the river through the water level control system, realize the control of the hydraulic gradient and flow rate upstream and downstream of the river, and then simulate the influence of the head difference between upstream and downstream of different rivers on the migration process of ship pollutants in the hyporheic zone; (4) The present invention can simulate the discharge of ship organic pollutants, domestic pollutants and variable-density chemical pollutants into rivers and hyporheic zones with different concentrations, flow rates and discharge durations through the pollutant simulation system, and trace the migration process of these three main types of ship pollutants in the hyporheic zone through different dyes; (5) The ship control system and ship model of the present invention can simulate the entry, migration and release process of ship pollutants in the hyporheic zone under the influence of different ship drafts, ship navigation speeds, ship pollutant discharge locations and ship navigation directions during the navigation process of ships in single-channel and double-channel coupling. It has strong operability and provides scientific guidance for the control and remediation of ship pollutants in rivers and hyporheic zones. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the main view of the ship control system, ship model and water level control system of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the left and right support plates of the ship control system in the present invention;

[0030] Figure 3 Schematic diagram of the structure of the partition plate in the present invention;

[0031] Figure 4 Schematic diagram of the structure of the ship model in the present invention;

[0032] Figure 5 Schematic diagram of the structure of the telescopic longitudinal rod in the present invention;

[0033] Figure 6 This is a schematic diagram of the assembly of the connector and the chain in the present invention;

[0034] Figure 7 Schematic diagram of the structure of the second water tank in the water level control system of the present invention;

[0035] Figure 8 This is a schematic structural diagram of the water-permeable plate in the water level control system of the present invention;

[0036] Figure 9 Schematic diagram of the main view of the pollutant simulation system of the present invention;

[0037] Figure 10 This is a schematic diagram of the main view of the pollutant monitoring system and the high-definition camera system in the present invention. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0039] like Figures 1 to 10 As shown, the present invention provides an experimental device for simulating the migration of pollutants from ships in a hyporheic zone, comprising a simulated river flume 1, a ship model, a ship control system, a water level control system, a pollutant simulation system, a pollutant monitoring system and a camera system.

[0040] like Figure 1 and Figure 2 As shown, the simulated river flume 1 is a five-sided, watertight box structure with a 2cm thick metal bottom, a 1.5cm thick metal plate on the back, and a 2cm thick transparent acrylic plate on the front. It is 400cm long, 10cm wide, and 70cm high. The simulated river flume 1 is placed vertically, and its interior is divided from left to right by a partition 104 into an upstream river area 101, a boat-like river simulation area 102, and a downstream river area 103. Figure 3 As shown, the partition 104 is permeable on the top and impermeable on the bottom. The partition 104 is composed of an acrylic plate with small holes on the top and a solid bottom, and a mesh. The partition 104 is 1.5 cm long, 10 cm wide, and 70 cm high. The partition is an acrylic plate with permeable holes evenly distributed on the top, and the outer periphery of the acrylic plate is covered with mesh. The upstream area 101 simulates the upstream boundary of the river with a constant head. The upstream area 101 is connected to the water level control system on the left through three first water inlets and outlets 105. The ship-passing river simulation area 102 simulates the overlying water and undercurrent zone of the ship-passing river. The undercurrent zone is composed of filled white quartz sand with a particle size of d 50 =0.24mm,d 90 / d 10 =2.86; the saturated hydraulic conductivity of the experimental sand measured by the constant head method is 4.78×10 -3 ms -1The porosity is 0.46. The sand sample was washed several times with deionized water before use. The downstream river area 103 simulates the downstream boundary of a river with a constant water head. The downstream river area 103 is connected to the water level control system on the right side via three first water inlets and outlets. The upstream river area 101 simulates the upstream boundary of a river with a constant water head. The ship-passing river simulation area 102 simulates the overlying water and subsurface flow zone of a ship-passing river. The downstream river area 103 simulates the downstream boundary of a river with a constant water head. Water in the upstream river area 101 flows through the permeable holes in the divider to the ship-passing river simulation area, and water in the ship-passing river simulation area 102 flows through the permeable holes in the divider to the downstream river area 103.

[0041] like Figure 2 As shown, a ship model navigates within a simulated river area 102. A ship control system is located above a simulated river flume 1 and drives the ship model to simulate dual-channel ships traveling in opposite directions. The control system includes a support plate 2, a reduction motor 3, an adjustable voltage-stabilized power supply 4, a driving guide wheel 5, a support 6, a driven guide wheel 7, and a chain 8. The reduction motor 3 is a miniature DC reduction motor, and the adjustable voltage-stabilized power supply 4 is a PS-305DM adjustable voltage-stabilized power supply. Two support plates 2 are respectively fixed on the top of the left and right sides of the simulated river flume 1. The support plates are made of metal plates with a length of 3 cm, a width of 10 cm, and a height of 20 cm. The micro DC reduction motor 3 is fixed on the inner wall of the support plate 2. The micro DC reduction motor 3 is fixed in a horizontal position close to the front of the support plate 2, and the micro DC reduction motor 3 is fixed in a vertical position 5 cm away from the top of the support plate 2. The support 4 is fixed on the inner wall of the support plate 2. The support 6 is fixed in a horizontal position close to the back of the support plate 2, and the support 6 is fixed in a vertical position 5 cm away from the top of the support plate 2. The adjustable voltage-stabilized power supply 4 is fixed on the outer wall of the support plate 2 and is 15 cm away from the top of the support plate 2. The adjustable voltage-stabilized power supply 4 controls the speed and direction of the reduction motor 3 through wires. The active guide wheel 5 is welded to the reduction motor 3, and the driven guide wheel 7 is welded to the support 6 On the upper part, the chain 8 is placed on the driving guide wheel 5 and the driven guide wheel 7 to ensure that the protruding meshing parts of the driving guide wheel 5 and the driven guide wheel 7 are completely placed in the gap of the chain 8. The pitch gap size of the chain 8 is: 3.5 cm. Through the support plates 2, the driving guide wheel 5, the driven guide wheel 7 and the chain 8 on the left and right sides, two parallel ship navigation channels are completed. The rotation speed of the reduction motor 3 is controlled by controlling the voltage value in the adjustable voltage-stabilized power supply 4 to simulate the influence of different navigation speeds on the migration of pollutants in the undercurrent zone. By placing multiple ship models on the chain, the influence of multiple ships emitting pollutants together is simulated. By adjusting the reversal of the adjustable voltage-stabilized power supply 4, the influence of ships emitting pollutants in different sailing directions is simulated. By placing ship models on two parallel channels, the influence of ships traveling in opposite directions in two channels on pollutant emissions is simulated.

[0042] like Figure 1 and Figure 4As shown, the ship model includes a hull 9, a crossbeam 10, a connecting longitudinal rod 12, a connecting crossbeam 13, a telescopic longitudinal rod 14, an inner sleeve 1401, a hemisphere 1402, a first spring 1403, an outer sleeve 1404, a circular hole 1405, a connector 15, a hollow cuboid 1501, a telescopic plate 1502, and a second spring 1503. The hull 9 is a plastic hull with a length of 10 cm, a width of 3 cm, and a height of 5 cm. Three small holes with a diameter of 1 cm are opened on the side of the hull 9. The crossbeam 10 is made of a plastic plate with a length of 10 cm, a width of 1 cm, and a height of 2 cm. The crossbeam 10 is fixed to the inner wall of the hull 9 and has three hollow grooves with a diameter of 1 cm at 2 cm, 5.5 cm, and 9 cm from the left side of the crossbeam 10. The connecting longitudinal rod 12 is made of a solid plastic plate with a length of 1 cm, a width of 1 cm, and a height of 20 cm. The two connecting longitudinal rods 12 are fixed on the crossbeam 10 in the middle of the three pollutant discharge pipes 11. One end of the two connecting longitudinal rods 12 is fixed on the crossbeam 10, and the other end of the two connecting longitudinal rods 12 is fixed on the connecting crossbar 13. The connecting crossbar 13 is made of solid plastic with a length of 5.5 cm, a width of 1 cm, and a height of 1 cm. The connecting crossbar 13 is used to ensure the front and rear force balance of the ship during navigation and to prevent rollover. The telescopic longitudinal rod 14 is fixed in the middle of the connecting crossbar 13. Figure 5 As shown, the telescopic longitudinal rod 14 includes an inner sleeve 1401 and an outer sleeve 1404. The inner sleeve 1401 is a hollow stainless steel cylinder with an inner diameter of 2 cm and a height of 15 cm. Two symmetrical hemispheres 1402 are provided on the top of the inner sleeve 1401. The two hemispheres 1402 have an inner diameter of 1 cm and are connected by a first spring 1403 inside the inner sleeve 1401. The outer sleeve 1404 is a hollow stainless steel cylinder with an inner diameter of 2.3 cm and a height of 15 cm. Circular holes with an aperture of 1 cm are provided on the outer sleeve 1404 every 2.5 cm. The relative position of the inner sleeve 1401 and the outer sleeve 1404 can be adjusted by controlling the contraction and relaxation of the hemispheres 1402, thereby adjusting the total length of the telescopic longitudinal rod 14. The connector 15 is fixed to the top of the outer sleeve 1404. Figure 6 As shown, the connector 15 includes a hollow cuboid 1501, a telescopic plate 1502 and a second spring 1503. The hollow cuboid 1501 is made of a 6-sided stainless steel tube with a length of 3 cm, a width of 2 cm and a height of 1.5 cm. Small holes with a length of 1 cm and a width of 1 cm are opened on both sides of the hollow cuboid 1501. The telescopic plate 1502 is made of solid plastic with a length of 1.2 cm, a width of 1 cm and a height of 1 cm. The telescopic plates 1502 are placed in the small holes on both sides of the hollow cuboid 1501. The two telescopic plates 1502 are connected by the second spring 1503. The length of the connector 15 can be adjusted by compressing and relaxing the telescopic plates 1502. After contracting the telescopic plates 1502, the connector 15 is placed on the chain 8 and then the telescopic plates 1502 are relaxed to ensure that the connector 15 and the entire ship model are fixed on the chain 8 when the experiment is running.

[0043] like Figure 1 and Figure 7 As shown, the water level control system is connected to the upstream area 101 and the downstream area 103 of the river respectively. The water level control system is used to control the upstream and downstream water levels of the simulated river during the experiment. The water level control system includes a first water tank 16, a first submersible pump 17, a first water pipe 18, a working platform 19, a pier 20, a second water tank 21, a bottom water inlet 2101, a bottom water outlet 2102, a second water inlet and outlet 2103, a control valve 2104, a first overflow plate 2105, a permeable plate 2106, a second overflow plate 2107, a wire rope 2108, a buckle 2109 and a second water pipe 2110. The first submersible pump 17 is a 370W10 submersible pump. The first water tank 16 is a stainless steel box structure with five impermeable sides. The dimensions of the first water tank 16 are 100 cm long, 100 cm wide and 35 cm high. It is used to store the simulated river water required for the experiment. The simulated river water is configured with deionized water. The first submersible pump 17 is placed at the bottom of the first water tank 16. The first submersible pump 17 is connected to the bottom water inlet 2101 of the second water tank 21 through the first water pipe 18. The bottom water outlet 2102 of the second water tank 21 is connected to the first water tank 16 through the first water pipe 18. The working platform 19 is fixed to the ground. The piers 20 are made of solid steel with a length of 5 cm, a width of 5 cm and a height of 10 cm. Four piers 20 are fixed on the working platform 19. The second water tank 21 is fixed on four On the pier 20, the second water tank 21 includes a bottom water inlet 2101, a bottom water outlet 2102, three second water inlets and outlets 2103 on the side, three control valves 2104, a first overflow plate 2105, a permeable plate 2106, a second overflow plate 2107 that can move up and down, a wire rope 2108 and a buckle 2109. The second water tank 21 is a stainless steel box structure that is impermeable on five sides. The second water tank 21 has a size of 60 cm long, 60 cm wide and 50 cm high. It is used to simulate the stable water level of the upstream and downstream of the river through the overflow effect. The first overflow plate 2105 is fixed in the middle position of the bottom of the second water tank 21. The first overflow plate 2105 is a stainless steel plate with a length of 3 cm, a width of 60 cm and a height of 20 cm. Figure 8As shown, the permeable plate 2106 is an acrylic plate with a length of 1 cm, a width of 60 cm, and a height of 50 cm, and its surface is covered with small holes. The permeable plate 2106 is fixed to the inner wall of the second water tank 21, and the position of the permeable plate 2106 is fixed 3.1 cm to the left of the first overflow plate 2105. A sliding groove is formed between the first overflow plate 2105 and the permeable plate 2106 to keep the left and right position of the second overflow plate 2107 unchanged and to slide up and down. The second overflow plate 2107 is a stainless steel plate with a length of 3 cm, a width of 60 cm, and a height of 30 cm. The second overflow plate 2107 is placed in the sliding groove, and one end of the wire rope 2108 is fixed to the top of the second overflow plate 2107, and the other end of the wire rope 2108 passes through the buckle 2109. The buckle 2109 is a hollow semi-cylindrical stainless steel. The buckle 2109 is fixed to the top of the second water tank. According to the experimental needs, the wire rope 2108 is pulled upward and loosened downward to control the second overflow plate 2107 to slide up and down in the sliding groove according to the water levels upstream and downstream of the river. After the top elevation of the second overflow plate 2107 reaches the predetermined position, the wire rope 2108 is knotted and fixed in the buckle 2109 to ensure that the position of the second overflow plate 2107 remains fixed. The three second water inlets and outlets 2103 are hollow cylinders. One side of the second water inlet and outlet 2103 is installed on the side of the second water tank 21, and the three control valves 2104 are installed on the other side of the second water inlet and outlet 2103. The control valve 2104 is connected to the simulated river water tank 1 through the second water pipe 2110, which is used to control the upstream and downstream water levels of the simulated river during the experiment, thereby realizing the simulation of the migration process of ship pollutants in the subsurface zone due to the hydraulic gradient of the upstream and downstream of the river.

[0044] like Figure 4 and Figure 9As shown, the pollutant simulation system is connected to the ship model. The pollutant simulation system is used to simulate the pollutant discharge on the ship model. The pollutant simulation system includes a first standard solution tank 22, a second standard solution tank 23, a third standard solution tank 24, a first peristaltic pump 25, a second peristaltic pump 26, a third peristaltic pump 27, a four-way connector 28, a transparent hose 29 and a pollutant discharge pipe 11. The first standard solution tank 22, the second standard solution tank 23 and the third standard solution tank 24 are of the same size, all of which are five-sided waterproof stainless steel box structures with a length of 30 cm, a width of 30 cm and a height of 30 cm. The first peristaltic pump 25, the second peristaltic pump 26 and the third peristaltic pump 27 are all BW100 peristaltic pumps, and the transparent hose 29 is a silicone transparent hose. The interior of the first standard solution tank 22 is a simulated organic pollutant solution dyed with methylene blue MB. The first standard solution tank 22 is connected to the first peristaltic pump 25 through the transparent hose 29. The first standard solution tank 22 can simulate the release of ship organic oil pollutants. The interior of the second standard solution tank 23 is a nutrient salt pollutant ammonia nitrogen solution dyed with brilliant blue BB. The second standard solution tank 23 is connected to the second peristaltic pump 26 through a transparent hose 29. The second standard solution tank 23 simulates the release of nutrient-rich domestic sewage from a ship. The interior of the third standard solution tank 24 contains a NaCl solution dyed with allura red AR. The third standard solution tank 24 is connected to the third peristaltic pump 27 through a transparent hose 29. The third standard solution tank 24 simulates the release of variable-density chemical pollutants from a ship. The first peristaltic pump 25, the second peristaltic pump 26 and the third peristaltic pump 27 are respectively connected to the three hollow cylinders on the upper part of the four-way joint 28 through a transparent hose 29. A hollow cylinder at the lower part of the four-way joint 28 is connected to the top of the pollutant discharge pipe 11 in the ship model through a transparent hose 29. Three hollow grooves with a diameter of 1 cm are set at 2 cm, 5.5 cm and 9 cm away from the left side of the beam 10 respectively. Three pollutant discharge pipes 11 are fixed on the beam 10 through the three hollow grooves respectively to simulate the impact of pollutant release at the front, middle and rear of the ship. The pollutant discharge pipe 11 is an L-shaped water pipe with a diameter of 1 cm. The top of the pollutant discharge pipe 11 is perpendicular to the bottom of the hull 9. The three pollutant discharge pipes 11 are respectively fixed to the three small holes on the side of the hull 9, and the bottom of the pollutant discharge pipe 11 is perpendicular to the side of the hull 9 and extends out of the hull 9. By controlling the switches of the first peristaltic pump 25, the second peristaltic pump 26 and the third peristaltic pump 27, the effects of the discharge of ship organic oil pollutants, domestic sewage and variable-density chemical pollutants are simulated respectively; by connecting with the pollutant discharge pipes 11 at different positions, the effects of the discharge of ship pollutants at the front, middle and rear of the ship are simulated; by controlling the delivery flow rates of the first peristaltic pump 25, the second peristaltic pump 26 and the third peristaltic pump 27, the effects of different ship pollutant emission rates are simulated; by opening and closing the time points of the first peristaltic pump 25, the second peristaltic pump 26 and the third peristaltic pump 27, the effects of different ship pollutant emission durations are simulated.

[0045] like Figure 10 As shown, the pollutant monitoring system is used to monitor the temporal and spatial variation of pollutants in the river overlying water and undercurrent zone under different ship pollutant discharge conditions. The pollutant monitoring system includes a sampling hole 30, an integrated sensor 31, a data processor 32 and a display 33. Six rows of sampling holes 30 are arranged at different depths of 5cm, 15cm, 25cm, 35cm and 45cm on the metal plate at the back of the simulated river water tank 1. The sampling holes 30 are hollow cylinders with an inner diameter of 0.5cm. The sampling holes 30 are filled with white silica gel to prevent the surface and groundwater seepage in the simulated river water tank and facilitate the insertion of the micro-sampler needle for sampling. The integrated sensor 31 includes a COD probe, an ammonia nitrogen probe and a conductivity probe. The COD probe, the ammonia nitrogen probe and the conductivity probe respectively measure the change data of ship organic pollutants, domestic pollutants and variable density chemical pollutants in the hyporheic zone. Three rows of integrated sensors 31 are arranged at different depths of 10cm, 30cm and 40cm at the back of the simulated river water tank 1. The integrated sensors 31 arranged at a depth of 10cm and 30cm mainly monitor the high-precision organic pollutants, ammonia nitrogen and conductivity data in the hyporheic zone. The integrated sensor 31 arranged at a depth of 40cm mainly monitors the actual data of ship pollutants in the overlying water of the river. In order to obtain the real-time data, three rows of integrated sensors 31 are arranged at 200 cm, 250 cm and 300 cm to the left of the downstream area 103 of the river. Taking into account that the upstream water level of the simulated river flume 1 is higher than the downstream water level, which causes the pollutants to migrate downstream, the integrated sensors 31 are arranged near the downstream to more accurately monitor the real-time data of the ship pollutant concentration. One end of the data processor 32 is connected to the integrated sensor 31, and the other end of the data processor 32 is connected to the display 33. The integrated sensor 31 can accurately monitor the changes in pollutant concentrations at different positions of the overlying water and undercurrent zone in the simulated river flume 1 at high frequency, and transmit the information to the data processor 32 via wire. The data processor 32 can save all the original data of the sensors during the experiment to form an experimental record file, which is visualized on the display 33 after post-processing analysis, thereby realizing in-situ monitoring of the temporal and spatial changes of pollutants in the overlying water and undercurrent zone of the river under different ship pollutant emission conditions. The integrated sensors 31 arranged as above can monitor the pollutant concentration data of ship pollutants in the river overlying water and subsurface zone groundwater during the ship's voyage at high frequency. By considering the data processing formulas of generalized convective transport, chemical reactions and ship pollution sources, combined with the initial conditions, emission flow and duration of the organic oil pollutants, domestic sewage and variable density chemical pollutants discharged by the pollutant simulation system, the exchange flux of ship pollutants in the river overlying water and subsurface zone during the ship's voyage, as well as the entry, migration and release process of pollutants in the subsurface zone, are derived.

[0046] The camera system is used to capture the process of ship pollutant tracing in a simulated river and hyporheic zone. The camera system is a high-definition camera system and includes a camera 34, a computer 35, a blackout curtain 36, and a lighting panel 37. Camera 34 is a high-definition camera, and computer 35 is a desktop computer. Computer 35 is connected to camera 34, and the camera's shooting frequency and duration are controlled by Camera Control Pro software. Camera 34 is placed in front of the simulated river flume 1 to obtain the optimal shooting angle. The lighting panel 37 is placed directly above the simulated river flume 1 and consists of a uniformly distributed LED light strip. To eliminate external light interference and ensure optimal imaging quality, a blackout curtain 36 measuring 4 meters long, 2 meters high, and 1.5 meters wide is installed around camera 34, lighting panel 37, and simulated river flume 1, creating a darkroom environment. By precisely controlling shooting parameters and operating the high-definition camera system under blackout conditions, high-quality images of the ship pollutant tracing process in the simulated river and hyporheic zone can be obtained.

[0047] The present invention provides an implementation method of an experimental device for simulating the migration of ship pollutants in the hyporheic zone, comprising the following steps:

[0048] (1) Prepare ship pollutant solution. The simulated solution of ship organic oil pollutants is prepared by mixing deionized water and methylene blue MB and placing it into the first standard solution tank 22. According to the experimental working conditions, 0.5g, 1g and 2g of methylene blue MB are added to 10L of deionized water, representing the concentration of ship organic oil pollutants simulated solution is 50mg / L, 100mg / L and 200mg / L respectively; the simulated solution of ship nutrient-rich domestic pollutants is prepared by mixing deionized water, analytical pure ammonium chloride NH4Cl and brilliant blue BB dye and placing it into the second standard solution tank 23. According to the experimental working conditions, 1.910g of , 3.819g and 7.638g analytical pure ammonium chloride NH4Cl, representing that the ammonia nitrogen concentration of the ship life pollutant simulation solution is 50mg / L, 100mg / L and 200mg / L respectively; the ship variable density chemical pollutant simulation solution is mixed with deionized water, industrial salt NaCl and edible allura red AR dye and placed into the third standard solution tank 24 for standby use. According to the experimental working conditions, 150g, 300g and 450g industrial salt NaCl are added to 10L deionized water, representing that the concentration of the ship chemical pollutant simulation solution is 15g / L, 30g / L and 45g / L respectively, and the corresponding density is 1010kg / m 3 、1021kg / m 3 and 1032kg / m 3 The three types of pollutants in the three standard solution boxes are prepared with methylene blue MB, brilliant blue BB and edible allure red AR dyes to distinguish the migration process of the three types of pollutants;

[0049] (2) Arrange the simulated river and riverbed, close all the control valves 2104 on the sides of the second water tank 21 on the left and right sides of the simulated river flume 1, add 200L of deionized water to the first water tank 16, adjust the position of the second overflow plate 2107 in the second water tank 21 by pulling the 2108 wire rope upward, and when the top elevation of the second overflow plate 2107 reaches the preset experimental position, tie the 2108 wire rope and fix it on the 2109 buckle to ensure that the second overflow plate 2107 is fixed in the sliding groove, turn on the first submersible pump 17 to supply water to the water inlet 2101 at the bottom of the second water tank through the first water pipe 18, observe that after the second water tank 21 is filled with water, the excess deionized water flows over the second overflow plate 2107 to the water outlet 2102 at the bottom of the second water tank, and returns to the first water tank 16 through the first water pipe 18. By adjusting the position of the second overflow plate 2107, the water level of the simulated river upstream and downstream can be adjusted; the sieve particle size is d 50 =0.24mm,d 90 / d 10 = 2.86 quartz sand and then washed with deionized water for multiple times. The washed quartz sand is placed in a bucket by saturating with water. The washed quartz sand is laid layer by layer in the simulated river water tank 1 by saturating with water. After laying a layer of quartz sand along the simulated river water tank 1, the back of the simulated river water tank 1 is tapped lightly to ensure that bubbles in the hyporheic zone are removed. When laying the riverbed and hyporheic zone, the water level in the simulated river water tank is always 10 cm higher than the filled quartz sand.

[0050] (3) Arrange high-definition cameras and integrated sensors, set up camera 34 1 m in front of the simulated river flume 1, adjust the height and focal length parameters of camera 34, connect camera 34 to computer 35, and control the shooting duration and frequency of camera 34 through Camera Control Pro to ensure that the migration process of ship pollutants during the experiment is recorded; calibrate the COD probe, ammonia nitrogen probe and conductivity probe in the integrated sensor 31 with COD, ammonia nitrogen and salinity standard solutions and connect them to the data processor 32. During the sand filling process for the experiment, place the integrated sensor 31 at the preset position on the back of the simulated river flume.

[0051] (4) Adjust the navigation parameters of the ship. Compress the telescopic plate 1502 of the connector 15 of the ship model and place it on the running chain. After it is placed stably, loosen the telescopic plate 1502 to ensure that the connector 15 and the corresponding ship model can move at the same speed as the chain. According to the experimental requirements, connect the four-way connector 28 in the pollutant discharge system to the top of the pollutant discharge pipe 11 at the front, middle or rear of the hull 9 through the transparent hose 29 to simulate the impact of pollutants discharged at the front, middle or rear of the hull on the undercurrent zone during the navigation of the ship. By controlling the contraction and relaxation of the hemisphere 1402 at the top of the inner sleeve 1401 in the telescopic longitudinal rod 14, the hemisphere 1402 is moved downward. 02 On the circular holes 1405 at different positions of the outer sleeve 1403, the relative positions of the inner sleeve 1401 and the outer sleeve 1404 can be adjusted to change the total length of the telescopic longitudinal rod 14. Since the height of the chain 8 remains unchanged, the draft of the ship can be adjusted by adjusting the length of the telescopic longitudinal rod; by adjusting the voltage of the adjustable voltage-stabilized power supply 4, the rotation speed of the reduction motor 3 can be controlled to adjust the running speed of the ship; by placing ship models on two parallel channels, the impact of ships traveling in opposite directions in the two channels on pollutant emissions is simulated; by adjusting the reverse direction of the adjustable voltage-stabilized power supply 4, the impact of ships sailing in different directions on pollutant emissions is simulated;

[0052] (5) Run the experiment, open the side control valves 2104 of the second water tank 21 on the left and right sides of the simulated river flume 1, so that the left and right water heads enter the simulated river and the undercurrent zone. Due to the different water heads on the left and right sides of the simulated river flume 1, a water head difference between the upstream and downstream of the river and the surface water flow rate are generated; turn on the adjustable voltage-stabilized power supply 4 to make the reduction motors 3 on the support plates 2 on the left and right sides of the simulated river flume 1 drive the active guide wheel 5 to rotate, thereby completing the stable circulation operation of the chains 8 of the two channels, ensuring that the ship sails at a preset speed on the free surface of the simulated river; respectively turn on and adjust the flow rates of the first peristaltic pump 25, the second peristaltic pump 26 and the third peristaltic pump 27, so that the methylene blue water flows in the water. Blue organic pollutants, bright blue domestic pollutants, and bright red variable-density pollutants were discharged into the simulated river and hyporheic zone at different rates during the ship's voyage. During the experiment, a microsampler was used to extract the simulated river overlying water and hyporheic zone pore water through the sampling hole 30 on the back of the simulated river flume 1. The integrated sensor 31 recorded the changes in the ship's organic pollutants, domestic pollutants, and variable-density chemical pollutants in real time during the ship's voyage. A camera 34 was used to take pictures every 10 seconds, and the migration process of the three ship pollutants in the river overlying water and hyporheic zone was recorded in a computer 35. In each set of experiments, the three pollutants were not released simultaneously.

[0053] (6) Stop the experiment and data analysis. When the ship pollutants have completely entered the hyporheic zone and the corresponding pollution plume no longer changes shape, the experiment is terminated. Turn off all system power supplies, remove the experimental sand and wash it with deionized water, and then repeat the next set of experiments according to the above steps; organize photos of the ship at different times during the navigation process, and qualitatively observe the tracing characteristics of various ship pollutants migrating in the hyporheic zone under the influence of different river water level gradients, ship pollutant emission rates, ship pollutant emission durations, ship drafts, and ship navigation speeds; by analyzing the in-situ data of the concentration changes of three types of ship pollutants at different locations, quantitatively evaluate the response relationship between ship operation characteristics, pollutant emission characteristics, and the migration process of pollutants in the hyporheic zone;

[0054] The total volume V of the hyporheic zone in the sand slope at the bottom of the river is calculated by hp As the control body, the following formula is fitted to describe the mathematical relationship between the change of pollutant concentration in the hyporheic zone and the characteristics of ship pollutant emissions and ship operation:

[0055]

[0056] The average concentration of pollutants monitored by sampling holes and integrated sensors in the hyporheic zone is C hp,i In the formula, the subscript i represents the concentration of the i-th pollutant, i=1, 2, 3 represent ship organic pollutants, domestic pollutants and variable density chemical pollutants respectively, and the organic pollutant concentration of the first standard solution tank is C point1 , the concentration of domestic pollutants in the second standard solution tank is C point2 , the variable density pollutant concentration in the third standard solution tank is C point3 , the flow rate of the first peristaltic pump is Q point1 , the flow rate of the second peristaltic pump is Q point2 , the flow rate of the third peristaltic pump is Q point3 , the undercurrent flow rate is Q out .

[0057] The present invention directly observes the occurrence forms and concentrations of pollutants in the hyporheic zone under the action of different ship pollutants, and conducts experiments on the entry, migration and release processes of ship pollutants in the hyporheic zone.

Claims

1. An experimental device for simulating the transport of ship pollutants in the hyporheic zone, characterized in that: The invention comprises a simulated river flume (1) which is divided from left to right into an upstream river area (101), a ship-traveling river simulation area (102) and a downstream river area (103); a ship model sailing in the ship-traveling river simulation area (102); a ship control system arranged above the simulated river flume (1) and used to drive the ship model to simulate the opposite travel of a dual-channel ship; a water level control system respectively connected to the upstream river area (101) and the downstream river area (103) and used to control the upstream and downstream water levels of the simulated river during the experiment; a pollutant simulation system connected to the ship model and used to simulate the discharge of pollutants on the ship model; a pollutant monitoring system used to monitor the temporal and spatial variation of pollutants in the river overlying water and the hyporheic zone under different ship pollutant discharge conditions; and a camera system used to photograph the ship pollutant tracing process in the simulated river and the hyporheic zone; the ship model comprises a hull (9); a crossbeam (10) fixed to the inner wall of the hull; connecting longitudinal rods (12) symmetrically arranged vertically on the crossbeam; A connecting crossbar (13) located at the ends of two connecting longitudinal rods, a telescopic longitudinal rod (14) connected to the connecting crossbar and capable of being telescoped up and down, and a connector (15) connected to the telescopic longitudinal rod and used for being clamped on a ship travel control system, wherein the telescopic longitudinal rod (14) comprises an inner sleeve (1401), two hemispherical bodies (1402) located at the top of the inner sleeve and symmetrically arranged, a first spring (1403) located in the inner sleeve and having two ends respectively connected to the hemispherical bodies on both sides, and an outer sleeve (1403) sleeved on the upper end of the inner sleeve. 404) and circular holes (1405) evenly spaced and arranged on the outer sleeve for fitting the hemisphere; the connector (15) comprises a hollow cuboid (1501) fixed to the top of the outer sleeve, telescopic plates (1502) located at both ends of the hollow cuboid, and a second spring (1503) located in the hollow cuboid and connected to the telescopic plates at both ends; the telescopic plates (1502) of the connector (15) of the ship model are compressed and placed on the chain (8) of the ship control system.

2. The experimental device for simulating the transport of pollutants from ships in the hyporheic zone according to claim 1 is characterized in that: The simulated river water tank (1) is a watertight box-type structure with an opening at the top, wherein the front of the simulated river water tank (1) is a transparent plate, and a partition plate (104) for separating areas and a first water inlet and outlet (105) connected to a water level control system are arranged in the simulated river water tank (1), wherein the partition plate is an acrylic plate with water-permeable holes evenly distributed on the upper portion, and the outer periphery of the acrylic plate is covered with a gauze.

3. The experimental device for simulating the transport of ship pollutants in the hyporheic zone according to claim 2 is characterized in that: The upstream area (101) of the river simulates the upstream boundary of the river with a constant water head, the ship-passing river simulation area (102) simulates the overlying water and the undercurrent zone of the ship-passing river, the undercurrent zone of the ship-passing river simulation area (102) is composed of filled white quartz sand, and the downstream area (103) of the river simulates the downstream boundary of the river with a constant water head. The water in the upstream area (101) flows to the ship-passing river simulation area through the water-permeable holes of the dividing plate, and the water in the ship-passing river simulation area (102) flows to the downstream area (103) of the river through the water-permeable holes of the dividing plate.

4. The experimental device for simulating the transport of ship pollutants in the hyporheic zone according to claim 1 is characterized in that: The boat control system comprises support plates (2) symmetrically fixed to the tops of two side plates of a simulated river flume (1), two groups of waterways arranged in parallel above the simulated river flume (1) and located between the two support plates, the waterway comprising a reduction motor (3) located on the inner side of one support plate, a driving guide wheel (5) connected to the output shaft of the reduction motor, a support (6) located on the inner side of the other support plate, a driven guide wheel (7) located on the support, a chain (8) wound around the driving guide wheel (5) and the driven guide wheel (7), and an adjustable voltage-stabilized power supply (4) located on the support plate and connected to the reduction motor via an electric wire.

5. The experimental device for simulating the transport of ship pollutants in the hyporheic zone according to claim 1 is characterized in that: The water level control system comprises a first water tank (16) for storing simulated river water required for the experiment, a first submersible pump (17) located in the first water tank, a working platform (19) located on the ground, and a second water tank (21) located on the working platform and used to simulate the stable water level of the upstream and downstream of the river through the overflow effect, a bottom water inlet (2101) located at the bottom of the second water tank and connected to the first submersible pump through a first water pipe (18), a bottom water outlet (2102) located at the bottom of the second water tank and connected to the first water tank through the first water pipe (18), and a second water inlet and outlet (2103) located on the side of the second water tank. , a control valve (2104) arranged on the second water inlet and outlet, a first overflow plate (2105) vertically arranged at the middle position of the bottom of the inner wall of the second water tank, a water-permeable plate (2106) vertically arranged at the bottom of the inner wall of the second water tank and spaced a certain distance from the first overflow plate to form a sliding groove, a second overflow plate (2107) located in the sliding groove and movable up and down along the sliding groove, a steel wire rope (2108) with one end fixed to the top of the second overflow plate, a buckle (2109) fixed to the top of the second water tank and used to pass the steel wire rope, and a second water pipe (2110) connected to the second water inlet and outlet (2103).

6. The experimental device for simulating the transport of ship pollutants in the hyporheic zone according to claim 1 is characterized in that: The pollutant simulation system comprises a first standard solution tank (22) containing a simulated organic pollutant solution, a second standard solution tank (23) containing simulated nutrient-rich domestic sewage of a ship, a third standard solution tank (24) containing simulated variable-density chemical pollutants of a ship, a first peristaltic pump (25) connected to the first standard solution tank via a transparent hose (29), a second peristaltic pump (26) connected to the second standard solution tank via a transparent hose, a third peristaltic pump (27) connected to the third standard solution tank via a transparent hose, a four-way connector (28) connected to the first peristaltic pump, the second peristaltic pump and the third peristaltic pump, and a pollutant discharge pipe (11) connected to the four-way connector via a transparent hose and uniformly distributed on the ship model.

7. The experimental device for simulating the transport of pollutants from ships in the hyporheic zone according to claim 1 is characterized in that: The pollutant monitoring system comprises sampling holes (30) distributed on the back of the simulated river tank, an integrated sensor (31) located in the simulated river tank and used to monitor the change data of ship organic pollutants, domestic pollutants and variable-density chemical pollutants in the hyporheic zone, a data processor (32) connected to the integrated sensor, and a display (33), wherein the integrated sensor comprises a COD probe, an ammonia nitrogen probe and a conductivity probe.

8. The experimental device for simulating the transport of ship pollutants in the hyporheic zone according to claim 1 is characterized in that: The camera system comprises a camera (34) located in front of the simulated river flume, a computer (35) connected to the camera, a light shielding curtain (36) surrounding the camera and the simulated flume, and a lighting panel (37) located directly above the simulated flume.

9. An experimental method for the experimental device for simulating the transport of pollutants from ships in the hyporheic zone according to any one of claims 1 to 8, characterized in that: The water level control system comprises a first water tank (16) for storing simulated river water required for the experiment, a first submersible pump (17) located in the first water tank, a working platform (19) located on the ground, and a second water tank (21) located on the working platform and used to simulate the stable water level of the upstream and downstream of the river through the overflow effect, a bottom water inlet (2101) located at the bottom of the second water tank and connected to the first submersible pump through a first water delivery pipe (18), a bottom water outlet (2102) located at the bottom of the second water tank and connected to the first water tank through the first water delivery pipe (18), a second water inlet and outlet (2103) located on the side of the second water tank, A control valve (2104) disposed on the second water inlet and outlet, a first overflow plate (2105) vertically disposed at the middle position of the bottom of the inner wall of the second water tank, a water-permeable plate (2106) vertically disposed at the bottom of the inner wall of the second water tank and spaced a certain distance from the first overflow plate to form a sliding groove, a second overflow plate (2107) located in the sliding groove and movable up and down along the sliding groove, a steel wire rope (2108) having one end fixed to the top of the second overflow plate, a buckle (2109) fixed to the top of the second water tank and used to pass the steel wire rope, and a second water pipe (2110) connected to the second water inlet and outlet (2103); The experimental method includes the following steps: (1) Prepare ship pollutant solutions. The simulated organic pollutant solution is prepared by mixing deionized water and methylene blue MB and placing it in the first standard solution tank. The simulated nutrient-rich domestic sewage of the ship is prepared by mixing deionized water, analytical grade ammonium chloride NH4Cl and brilliant blue BB dye and placing it in the second standard solution tank. The simulated variable density chemical pollutants of the ship are prepared by mixing deionized water, industrial salt NaCl and edible allure red AR dye and placing it in the third standard solution tank for standby use. The three types of pollutants in the three standard solution tanks are prepared by methylene blue MB, brilliant blue BB and edible allure red AR dye to distinguish the migration process of the three types of pollutants. (2) Arrange a simulated river and riverbed, close all control valves on the sides of the second water tank on both sides of the simulated river flume, add deionized water to the first water tank, adjust the position of the second overflow plate in the second water tank by pulling the wire rope upward, and when the top elevation of the second overflow plate reaches the preset position of the experiment, tie the wire rope and fix it on the buckle to ensure that the second overflow plate is fixed in the sliding groove between the first overflow plate and the permeable plate. Turn on the first submersible pump to supply water to the water inlet at the bottom of the second water tank through the first water pipe, and observe the excess deionized water flowing over the second overflow plate to the second water tank after the second water tank is filled with water. The water is discharged from the water outlet at the bottom of the tank and returns to the first water tank through the first water pipe. The water level of the upstream and downstream of the simulated river can be adjusted by adjusting the position of the second overflow plate; after screening the quartz sand, it is washed with deionized water for multiple times, and the washed quartz sand is placed in a bucket by saturating water. The washed quartz sand is laid layer by layer in the simulated river water tank by saturating water. After laying a layer of quartz sand along the simulated river water tank, tap the back of the simulated river water tank lightly to ensure that bubbles in the undercurrent zone are removed. When laying the riverbed and undercurrent zone, the water level in the simulated river water tank is always higher than a certain height of the filled quartz sand; (3) Arrange the camera and integrated sensor, set up the camera at a certain distance in front of the simulated river flume, adjust the camera parameters, connect the camera to the computer, control the camera shooting time and frequency, and ensure that the migration process of ship pollutants during the experiment is recorded; calibrate the COD probe, ammonia nitrogen probe and conductivity probe in the integrated sensor with COD, ammonia nitrogen and salinity standard solutions and connect them to the data processor. During the filling process of the experimental sand, place the integrated sensor at the preset position at the back of the simulated river flume; (4) Adjust the ship's navigation parameters. Compress the telescopic plate of the connector of the ship model and place it on the chain. After it is placed stably, loosen the telescopic plate to ensure that the connector and the corresponding ship model can move at the same speed as the chain. Connect the four-way connector in the pollutant simulation system to the top of the pollutant discharge pipe at the front, middle or rear of the hull through a transparent hose according to the experimental requirements to simulate the impact of pollutants discharged at the front, middle or rear of the hull on the undercurrent zone during the ship's navigation. Control the contraction and relaxation of the hemisphere at the top of the inner sleeve in the telescopic longitudinal rod so that the hemisphere is located on the circular holes at different positions of the outer sleeve. Adjust the relative position of the inner sleeve and the outer sleeve to change the total length of the telescopic longitudinal rod. Since the chain height remains unchanged, the draft of the ship can be adjusted by adjusting the length of the telescopic longitudinal rod. Control the rotation speed of the reduction motor by adjusting the voltage of the adjustable voltage regulator to adjust the ship's running speed. Place the ship model on two parallel channels to simulate the impact of ships traveling in opposite directions on pollutant emissions. Adjust the reversal of the adjustable voltage regulator to simulate the impact of ships' pollutant emissions in different sailing directions. (5) Run the experiment. Open the control valves on the sides of the second water tank on the left and right sides of the simulated river flume to allow the left and right water heads to enter the simulated river and the undercurrent zone. Due to the different water heads on the left and right sides of the simulated river flume, a water head difference between the upstream and downstream of the river and the surface water flow rate are generated. Turn on the adjustable voltage stabilizer to drive the reduction motors on the support plates on the left and right sides of the simulated river flume to drive the active guide wheels to rotate, thereby driving the chains of the two channels to operate stably in a cycle, ensuring that the ship sails at a preset speed on the free surface of the simulated river. Turn on and adjust the flow rates of the first peristaltic pump, the second peristaltic pump and the third peristaltic pump respectively to make the methylene blue During the ship's voyage, the bright blue organic pollutants, the bright blue domestic pollutants and the bright red variable density pollutants were discharged into the simulated river and the hyporheic zone at different rates. During the experiment, a micro sampler was used to extract the simulated river overlying water and the hyporheic zone pore water through the sampling hole on the back of the simulated river flume. The integrated sensor recorded the change data of the ship's organic pollutants, domestic pollutants and variable density chemical pollutants in real time during the ship's voyage. The camera was used to take timed photos and record the migration process of the three ship pollutants in the river overlying water and the hyporheic zone in the computer. In each group of experiments, the three pollutants were not released at the same time. (6) Stop the experiment and data analysis. When the ship pollutants have completely entered the hyporheic zone and the corresponding pollutants no longer change shape, the experiment is terminated. All system power supplies are turned off, the experimental sand is removed and washed with deionized water, and the next set of experiments are repeated according to the above steps; organize high-definition photos at different times during the ship's navigation process, and qualitatively observe the tracing characteristics of various ship pollutants migrating in the hyporheic zone under the influence of different river water level gradients, ship pollutant emission rates, ship pollutant emission durations, ship drafts, and ship navigation speeds; by analyzing the in-situ data of the concentration changes of three types of ship pollutants at different locations, quantitatively evaluate the response relationship between river water level gradients, ship operation characteristics, pollutant emission characteristics, and the migration process of pollutants in the hyporheic zone; By calculating the total volume V of the hyporheic zone in a sand slope at the bottom of the river hp As the control body, the following formula is fitted to describe the mathematical relationship between the change of pollutant concentration in the hyporheic zone and the characteristics of ship pollutant emission and ship operation as follows: ， The average concentration of pollutants monitored by sampling holes and integrated sensors in the hyporheic zone is C hp,i , small standard in formula i Indicates i Pollutant concentrations, i=1, 2, 3 represent ship organic pollutants, life pollutants and variable density chemical pollutants respectively. The organic pollutant concentration of the first standard solution tank is C point1 , the concentration of domestic pollutants in the second standard solution tank is C point2 , the variable density pollutant concentration in the third standard solution tank is C point3 , the flow rate of the first peristaltic pump is Q point1 , the flow rate of the second peristaltic pump is Q point2 , the flow rate of the third peristaltic pump is Q point3 , the undercurrent outflow is .

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