Rectification system and seabed sediment and underflow simulation device

Abstract

The invention discloses a rectification system which comprises a plurality of unit modules used for arranging water flow into laminar flow, and the unit modules are arranged in a layered mode in the vertical direction. The invention further discloses a seabed sediment and underflow simulation device which comprises a flow generation system, a rectification system and an experiment pool which are communicated in sequence. The flow generation system pushes water to generate water flow, the water flow is sorted into laminar flow through the rectification system and then input into the experiment pool, and a seabed sediment simulation layer is laid at the pool bottom of the experiment pool. By arranging the unit modules, water flow can be arranged into laminar flow, so that the laminar flow is closer to real seabed underflow, and the simulation degree of the real seabed sediment plume diffusion process is improved. Meanwhile, the unit modules are arranged in a vertical layered arrangement mode and are horizontally arranged, so that water flow discharged by each unit module is located at different heights, and each path of water flow diffuses in the horizontal direction at different heights, mutual interference between different water paths can be effectively reduced, and turbulent flow and vortex are prevented from being generated again.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of seabed bottom flow simulation devices, and in particular to a rectification system and a seabed bottom sediment and bottom flow simulation device. Background Art

[0002] Seabed sediment refers to the sediments on the seabed. According to the differences in its composition and characteristics, it can be divided into sand, mud and rock. Seabed bottom current refers to the ocean current that acts on the seabed in a long-term or permanent stable or semi-stable state driven by mechanisms such as temperature and salt or sea breeze. It is an important natural phenomenon in the marine environment. It has a profound impact on the balance of the seabed ecosystem, the transportation and distribution of seabed sediments, and the development and utilization of deep-sea mineral resources. During deep-sea mining operations, due to the disturbance of the seabed mining vehicle, the seabed sediment is stirred up and pushed by the seabed bottom current, thus generating a seabed sediment plume. The formation of the seabed sediment plume is the result of the combined action of the seabed sediment, the seabed bottom current, and external disturbance. The study of the plume diffusion process is of great significance to the marine environmental impact assessment.

[0003] In order to study the diffusion process of plume flow, domestic and foreign countries have carried out field tests on the seabed. However, due to the particularity and complexity of the deep-sea environment, the test cost is extremely high and the risk is extremely high, making it difficult to make substantial progress. Therefore, a test device that can effectively simulate the seabed environment is needed. Since most deep-sea polymetallic nodule mining areas belong to sea basin terrain, the seabed bottom current in this area is different from general fluids. It is laminar (Reynolds number Re < 2300) and the flow rate is 0.01~0.1m / s. The fluids produced by the simulation devices in the prior art are all turbulent (Reynolds number Re ≥ 2300), and it is difficult to simulate the bottom flow rate. At the same time, due to the significant difference between turbulent and laminar flows in the effect of pushing the stirred seabed sediment, it is difficult to effectively simulate the real seabed sediment plume diffusion process. The reason is mainly because the simulation devices in the prior art are mostly single-layer structures, that is, in the process of rectification, the water bodies in the upper, middle and lower layers will cross vertically, thereby affecting the rectification effect. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a device for simulating seabed sediment and bottom current.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A rectifying system includes a plurality of unit modules for rectifying water flow into laminar flow, wherein the unit modules are arranged in layers in a vertical direction; when water flows through the rectifying system, the water flow in the unit modules at each layer does not flow vertically. The unit modules arranged in layers in a vertical direction can comprehensively rectify water flow from different heights. Compared with an unlayered structure, the state of water flow at different vertical positions can be more accurately controlled, and the vertical flow of each layer of water flow during the rectifying process can be avoided, thereby effectively rectifying water flow into laminar flow, solving the problem that the existing technology is difficult to simulate the laminar flow state of the bottom flow of the seabed, and providing more realistic water flow conditions for the subsequent simulation of the plume diffusion process of the seabed sediment.

[0006] As a further improvement of the above technical solution: The unit module includes a buffer zone, which includes a plurality of buffer plates arranged in layers vertically, and the buffer plates are arranged in an arc or wave shape. The arc or wave-shaped buffer plates can disperse and buffer the water flow, slow down the water flow speed, make the water flow more stable, avoid the rapids and vortices in the water flow, and other conditions that are not conducive to the formation of laminar flow, further optimize the state of the water flow before entering the subsequent area, make the subsequent rectification process smoother, improve the laminar flow sorting effect, and be closer to the stable / semi-stable state of the bottom current.

[0007] The unit module also includes a rectifying area located downstream of the buffer zone, and the rectifying area includes a plurality of rectifying plates arranged at intervals along the direction of the water flow, and the rectifying plates are arranged as porous plates perpendicular to the direction of the water flow. The rectifying plates with a porous plate structure can carefully comb and rectify the water flow. When the water flows through the small holes on the porous plate, it is divided into multiple small streams of water. These small streams of water interact and merge, making the flow velocity of the water flow in the horizontal and vertical directions more uniform, thereby effectively arranging the water flow into laminar flow, overcoming the turbulence problem created by the simulation device in the prior art, and realizing the effective simulation of the bottom flow laminar flow of the seabed.

[0008] The unit module also includes a guide area located downstream of the rectification area, the guide area includes a plurality of front guide plates arranged in layers along the vertical direction, and a rear guide plate located downstream of the front guide plate, the front guide plate is arranged in an arc or wave shape, and the rear guide plate is arranged in a grid plate. The arc or wave-shaped front guide plate can provide preliminary guidance for the rectified water flow, guide the water flow to flow at a specific angle and direction, and make the water flow more orderly; the grid plate structure of the rear guide plate further fine-tunes the water flow, ensures the consistency of the water flow at different vertical positions, avoids deviation and turbulence of the water flow, and allows the water flow to stably enter the subsequent stable area, providing a more stable and more satisfactory water flow for simulating the real bottom current state of the seabed.

[0009] The unit module also includes a stable zone located downstream of the guide zone, and the stable zone is configured as a bell mouth with an inner diameter gradually increasing along the water flow direction. The stable zone of the bell mouth structure can gradually reduce the flow velocity of the water flow in the gradually expanding space and tend to be stable, further eliminating the small fluctuations and unstable factors in the water flow, ensuring that the output laminar flow has a high degree of stability and uniformity, meeting the requirements of simulating the stable / semi-stable state of the bottom flow, and providing a more reliable water flow environment for simulating the plume diffusion process of the bottom sediment.

[0010] Then, the present invention discloses a device for simulating seabed sediment and bottom current, which includes a flow-making system, the above-mentioned rectification system and an experimental pool connected in sequence; the flow-making system drives the water body to generate water flow, and the water flow is input into the experimental pool after being sorted into laminar flow by the rectification system, and the bottom of the experimental pool is paved with a seabed sediment simulation layer. This integrated simulation device structure realizes the complete process from water flow generation and sorting to simulating the seabed environment for experiments. Each system works together to effectively simulate the environment where the seabed sediment, seabed bottom current and external disturbances work together, and can carry out research on the diffusion process of seabed sediment plume flow in the laboratory at low cost and low risk, making up for the defects of high cost and high risk of field experiments.

[0011] As a further improvement of the above technical solution: The flow generation system includes a storage tank, a water pump and a valve connected in sequence; the storage tank is connected to the experimental pool, and the water level in the storage tank is higher than the water inlet of each water pump. By setting the water level in the storage tank higher than the water inlet of the water pump, the water flow can enter the water pump more smoothly with the help of gravity, reducing the energy consumption of the water pump, while ensuring the stability of the water flow supply, providing a stable water flow input for the subsequent rectification system, and ensuring that the entire simulation device can operate continuously and stably.

[0012] Each of the water pumps is connected to each valve. Through the design that each water pump is connected to each valve, the water flow rate and flow rate of each valve can be flexibly controlled, the water flow state can be accurately adjusted according to the experimental requirements, the adaptability and operability of the simulation device can be improved, and the requirements for seabed bottom current simulation under different experimental conditions can be met.

[0013] The valves are arranged in layers vertically, and their outlets are connected to the rectification system. The valves arranged in layers vertically can realize the separate control of water flows at different heights. With the vertical layered structure of the rectification system, the water flows at different vertical positions can be more accurately regulated and sorted, so that the water flows have better controllability when entering the rectification system, and the accuracy of simulating the laminar flow state of the bottom flow of the seabed is further improved.

[0014] The experimental pool is connected to the flow-generating system through a plurality of return pipes on the side away from the rectifying system, and the return pipes are arranged in layers vertically. The return pipes arranged in layers vertically can make the water flows at different heights in the experimental pool flow back to the flow-generating system respectively, realize the recycling of water bodies, reduce the waste of water resources, and at the same time ensure the stability and continuity of the water flow state in the experimental pool, so that the simulation experiment can be carried out for a long time, providing favorable conditions for the in-depth study of the diffusion process of the seabed sediment plume.

[0015] In general, by setting up the unit modules, the inflowing water flow can be organized into laminar flow, which is closer to the real bottom current, and thus can improve the simulation degree of the real seabed sediment plume diffusion process. At the same time, by setting the unit modules in a vertical layered arrangement, and each unit module is arranged horizontally, the water flow discharged by each unit module is at a different height, and each water flow diffuses horizontally at different heights, which can effectively reduce the mutual interference between different waterways and avoid the re-generation of turbulence and eddies. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the rectifier system; Figure 2 It is the flow velocity variation curve before and after the rectification system treatment; Figure 3 It is a schematic diagram of the structure of the device for simulating the bottom sediment and bottom current; Figure 4 Comparison of the effects of layered and non-layered settings.

[0017] The numbers in the figure represent: 1. Rectification system; 11. Unit module; 111. Buffer zone; 1111. Buffer plate; 112. Rectification area; 1121. Rectification plate; 113. Guide area; 1131. Front guide plate; 1132. Rear guide plate; 114. Stable area; 2. Flow-making system; 21. Storage tank; 22. Water pump; 23. Valve; 3. Experimental pool; 4. Seabed simulation layer; 5. Return pipe. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Example like Figure 1As shown, the rectification system of this embodiment includes five horizontally arranged unit modules 11, and the water flows into the unit modules 11 from the water inlet end, and is discharged from the water outlet end after being sorted by the unit modules 11. Each unit module 11 is provided with a top plate and a bottom plate, and the top plate and the bottom plate are both water-impermeable plates. In the process of water flowing through the rectification system, the water flows in each layer of the unit modules cannot penetrate the top plate and the bottom plate, so they can only flow in the corresponding unit modules 11 without generating vertical water flows. In other words, once the water flows into a certain unit module 11, it will inevitably flow out of the unit module 11, and will not enter different unit modules 11. The five unit modules 11 are arranged in layers vertically, and the water flows discharged from each unit module 11 are located at different heights. Because each unit module 11 is arranged horizontally, the water flows of each route are diffused in the horizontal direction at different heights, thereby effectively reducing the mutual interference between different waterways and avoiding the re-generation of turbulence and eddy currents.

[0020] Specifically, the unit module 11 includes a buffer zone 111, which is close to the water inlet end of the unit module 11, and includes four layers of wavy buffer plates 1111 evenly spaced in the vertical direction. A wavy gap is formed between adjacent buffer plates 1111. When the water flows in the gap, its kinetic energy is reduced and its flow direction is restricted, thereby effectively reducing the turbulence and eddy current in the water flow and reducing the Reynolds number Re. The unit module 11 also includes a rectifying area 112 located downstream of the buffer zone 111. The rectifying area 112 includes three rectifying plates 1121 arranged at intervals along the water flow direction and perpendicular to the water flow direction. The rectifying plate 1121 is configured as a porous plate, and the aperture located in the middle of the rectifying plate 1121 is larger than the aperture located at the edge of the rectifying plate 1121. When the water flowing through the buffer zone 111 passes through the holes on the rectifying plate 1121, its kinetic energy is further reduced, thereby further reducing the turbulence and eddy current in the water flow and reducing the Reynolds number Re. The unit module 11 also includes a guide area 113 located downstream of the rectifying area 112. The guide area 113 includes six front guide plates 1131 evenly spaced vertically. A wave-shaped gap is formed between adjacent front guide plates 1131. When the water flows in the gap, its kinetic energy is reduced and its flow direction is restricted, thereby effectively reducing the turbulence and eddy current in the water flow and reducing the Reynolds number Re. The guide area 113 also includes a grid-shaped rear guide plate 1132 located downstream of the front guide plate 1131. When the water flow in the gap of the front guide plate 1131 passes through the holes on the rear guide plate 1132, its kinetic energy is further reduced, thereby further reducing the turbulence and eddy current in the water flow and reducing the Reynolds number Re. The unit module 11 also includes a stable area 114 located downstream of the guide area 113. The stable area 114 is configured as a bell mouth with a gradually increasing inner diameter along the water flow direction. The stable areas 114 of adjacent unit modules 11 fit together. The water flow passing through the guide area 113 further eliminates turbulence and eddy currents in the stable area 114, so that the Reynolds number Re is reduced to below 2300, thereby ensuring that the laminar flow discharged outward after being processed by the rectification system is basically consistent with the bottom current of the seabed.

[0021] Electromagnetic single-point flowmeters are set at valve 23 and stable zone 114, and the two electromagnetic single-point flowmeters are at the same horizontal plane to monitor the flow velocity changes in real time. By comparing the flow velocity data at the two positions, it can be clearly observed that the water flow gradually changes from turbulent to laminar flow. Specifically, at valve 23, the flow velocity distribution shows large fluctuations and irregularities, indicating that the water flow is still in a turbulent state at this time; while at the stable zone 114, the flow velocity distribution tends to be stable and uniform, and the fluctuation amplitude is significantly reduced, indicating that the water flow has been transformed into laminar flow after being processed by the rectification system.

[0022] In order to prove that the turbulent flow can be sorted into laminar flow by setting the buffer zone 111, the rectifying zone 112, the guiding zone 113 and the stabilizing zone 114, the present invention conducts tests in the laboratory and obtains the flow velocity changes at the same level at the valve 23 and the stabilizing zone 114. Figure 2 As shown in the figure, it can be seen that the flow rate at valve 23 changes more drastically, with large fluctuations, and presents irregular fluctuations in the entire time period; while the flow rate at the stable area 114 changes relatively smoothly, with a small fluctuation amplitude, and presents a relatively stable change trend in the entire time period. Therefore, it can be seen that after being processed by the rectification system, the flow rate at the stable area 114 is significantly more stable than the flow rate at valve 23. This shows that the rectification system effectively reduces the fluctuation of the flow rate and improves the stability of the flow rate.

[0023] In addition, by calculating the Reynolds number (Re) formula:

[0024] Where:

[0025]

[0026] Taking the average flow rate values ​​of valve 23 and stable zone 114 during the experiment, the Reynolds number is calculated as shown in the following table: Table 1: Reynolds number results of two monitoring points

[0027] It can be seen from the table that at valve 23, the Reynolds number is relatively high, usually greater than 2300, which is consistent with the characteristics of turbulence; while at the stable zone 114, the Reynolds number drops below 2300, which is consistent with the characteristics of laminar flow. These data fully prove that by setting the buffer zone 111, the rectifying zone 112, the guiding zone 113 and the stable zone 114, the turbulent flow can be effectively sorted into laminar flow, thereby improving the simulation degree of the seabed sediment plume diffusion process.

[0028] Then, if Figure 3As shown, this embodiment also discloses a device for simulating bottom sediment and bottom flow, which includes a flow-making system 2, the above-mentioned rectifying system 1 and an experimental pool 3 which are connected in sequence; the flow-making system 2 drives the water body to generate water flow, and the water flow is input into the experimental pool 3 after being sorted into laminar flow by the rectifying system 1, and a bottom sediment simulation layer 4 is laid on the bottom of the experimental pool 3. The rectifying system 1 includes five horizontally arranged unit modules 11, and the water flow enters from the water inlet end of the unit module 11, becomes laminar flow after being sorted by the unit module 11, and then is discharged from the water outlet end. The five unit modules 11 are arranged in layers vertically, and the water level of the experimental pool 3 is higher than the outlet of each unit module 11. The water flow discharged from each unit module 11 is at a different height. Because each unit module 11 is arranged horizontally, each water flow diffuses in the horizontal direction at different heights in the experimental pool 3, thereby effectively reducing the mutual interference between different waterways and avoiding the re-generation of turbulence and eddy currents. In order to prove that the effect of vertically layered unit modules is better than that of non-layered units, two sets of identical underflow simulation devices were compared. One set of devices had a rectifier system with five unit modules arranged in vertical layers. The other set of devices had a rectifier system that combined the five unit modules into a whole without vertically layered arrangements. When other relevant parameters were completely consistent, flow velocity sensors were used to monitor the flow velocity values ​​at 0.3m, 0.8m, and 1.2m above the ground. The measurement results are as follows Figure 4 As shown. From the flow rate data, it can be seen that the flow rate at different heights is relatively stable with small fluctuations after the layered arrangement; while the flow rate of the non-layered device fluctuates greatly, especially at higher positions, the flow rate increases significantly, indicating that the non-layered device cannot effectively control the water flow velocity, resulting in large fluctuations in the water flow in the experimental pool. This proves that the vertical layered arrangement of the unit modules can effectively improve the stability of the water flow, reduce mutual interference between different waterways, and avoid the re-generation of turbulence and eddies.

[0029] At the same time, by laying a seabed simulation layer 4 on the bottom of the experimental pool 3, the combination scene of the seabed sediment and the seabed bottom current can be directly simulated in the experimental pool 3, thereby simulating the real seabed sediment plume diffusion process.

[0030] Specifically, the flow-making system 2 includes a storage tank 21, a water pump 22 and a valve 23 connected in sequence; the storage tank 21 is connected to the experimental pool 3 and is used to provide a water source for flow-making. The water level in the storage tank 21 is higher than the water inlet of each water pump 22, so that it is difficult for air to mix into the water pump 22, thereby effectively reducing the possibility of turbulence and eddy currents caused by air, thereby improving the stability of the water flow. Each water pump 22 is connected to each valve 23. The valves 23 are arranged in layers vertically, and their outlets are connected to the rectifier system 1. It is difficult to completely unify the mechanical properties of the water pump 22. By connecting each water pump 22 to each valve 23, the water flow conditions entering each valve 23 can be kept basically consistent, thereby avoiding obvious differences in the various water flows created due to performance differences of individual water pumps 22, that is, the overall stability of the water flow created by the flow-making system 2 can be improved.

[0031] More specifically, the side of the experimental pool 3 away from the rectifying system 1 is connected to the flow-generating system 2 through a plurality of return pipes 5, and the return pipes 5 are arranged in layers along the vertical direction. The laminar flow discharged from the rectifying system 1 diffuses in the horizontal direction at different heights in the experimental pool 3. By arranging a plurality of return pipes 5 in layers along the vertical direction on the side of the experimental pool 3 away from the rectifying system 1, water of different depths can be extracted from the experimental pool 3 at the same time, thereby reducing the movement of the pool water in the vertical direction to a certain extent, and further effectively reducing the mutual interference between different water layers and avoiding the re-generation of turbulence and eddies.

[0032] Furthermore, the seabed sediment and bottom current simulation device also includes a data acquisition and control system electrically connected to the water pump 22 and the valve 23 respectively. The system includes a flow sensor built into the water pump 22 for real-time monitoring of water flow. The data acquisition and control system regulates the power of the water pump 22 and the opening of the valve 23 according to the water flow data of each water pump 22 collected by the flow sensor, so that the flow velocity, flow rate and other indicators of the water flow in each waterway discharged through the valve 23 meet the test requirements.

[0033] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A rectifier system, characterized in that: It comprises a plurality of unit modules (11) for arranging water flow into laminar flow, wherein the unit modules (11) are arranged in layers vertically; when the water flow passes through the rectifying system, the water flow in the unit modules (11) at each layer does not flow vertically.

2. The rectifier system according to claim 1, characterized in that: The unit module (11) comprises a buffer zone (111), wherein the buffer zone (111) comprises a plurality of buffer plates (1111) arranged in layers vertically, and wherein the buffer plates (1111) are arranged in an arc shape or a wave shape.

3. The rectifier system according to claim 2, characterized in that: The unit module (11) further comprises a rectifying area (112) located downstream of the buffer zone (111), the rectifying area (112) comprising a plurality of rectifying plates (1121) arranged at intervals along the water flow direction, the rectifying plates (1121) being arranged as porous plates perpendicular to the water flow direction.

4. The rectifier system according to claim 3, characterized in that: The unit module (11) further comprises a guide area (113) located downstream of the rectifying area (112), the guide area (113) comprising a plurality of front guide plates (1131) arranged in layers in a vertical direction, and a rear guide plate (1132) located downstream of the front guide plates (1131), the front guide plates (1131) being arranged in an arc shape or a wave shape, and the rear guide plates (1132) being arranged in a grid plate.

5. The rectifier system according to claim 4, characterized in that: The unit module (11) further comprises a stabilization zone (114) located downstream of the guide zone (113), wherein the stabilization zone (114) is configured as a bell mouth with an inner diameter gradually increasing along the direction of water flow.

6. A device for simulating seabed sediment and bottom current, characterized in that: The method comprises a flow-generating system (2), a rectifying system (1) as claimed in any one of claims 1 to 5, and an experimental pool (3) which are connected in sequence; the flow-generating system (2) drives the water body to generate a water flow, and the water flow is rectified into a laminar flow by the rectifying system (1) and then input into the experimental pool (3); the bottom of the experimental pool (3) is paved with a seabed simulation layer (4).

7. The device for simulating seabed sediment and bottom current according to claim 6, characterized in that: The flow generation system (2) comprises a storage tank (21), a water pump (22) and a valve (23) which are connected in sequence; the storage tank (21) is connected to the experimental pool (3), and the water level in the storage tank (21) is higher than the water inlet of each water pump (22).

8. The device for simulating seabed sediment and bottom current according to claim 7, characterized in that: Each of the water pumps (22) is connected to each valve (23).

9. The device for simulating seabed sediment and bottom current according to claim 7, characterized in that: The valves (23) are arranged in layers vertically, and their water outlets are connected to the rectification system (1).

10. The device for simulating seabed sediment and bottom current according to claim 6, characterized in that: The experimental pool (3) is connected to the flow generation system (2) via a plurality of return pipes (5) on the side facing away from the rectification system (1), and the return pipes (5) are arranged in layers vertically.

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