A rectification system and a device for simulating seabed sediments and bottom currents

Abstract

The present invention discloses a rectification system, which includes several unit modules for arranging water flow into laminar flow, and the unit modules are arranged in layers along the vertical direction. Also disclosed is a seabed sediment and bottom flow simulation device, which includes a flow-generating system, a rectification system and an experimental pool connected in sequence; the flow-generating system drives the water body to generate water flow, and the water flow is input into the experimental pool after being rectified into laminar flow by the rectification system, and the bottom of the experimental pool is paved with a seabed sediment simulation layer. By setting the unit modules, the water flow can be arranged into laminar flow, which is closer to the real seabed bottom flow, thereby improving the degree of simulation of the real seabed sediment plume diffusion process. At the same time, by arranging 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 the water flow of each channel diffuses horizontally at different heights, thereby effectively reducing the mutual interference between different waterways and avoiding the re-generation of turbulence and eddy currents.

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] Seafloor sediment refers to the sediments on the seafloor, which can be categorized as sandy, muddy, or rocky, depending on its composition and properties. Seafloor currents are ocean currents that act on the seafloor in a long-term or permanent, stable or semi-stable state, driven by mechanisms such as temperature and salinity or sea breezes. They are a critical natural phenomenon in the marine environment, profoundly impacting the balance of seafloor ecosystems, the transport and distribution of seafloor sediments, and the development and utilization of deep-sea mineral resources. During deep-sea mining operations, the disturbance of seafloor mining vehicles stirs up the seafloor sediment and propels it forward, generating a sediment plume. The formation of a sediment plume is the result of the combined effects of the seafloor sediment, the current, and external disturbances. Research on the diffusion process of this plume is of great significance for marine environmental impact assessments.

[0003] To study the diffusion process of plumes, field experiments have been conducted on the seabed both domestically and internationally. However, due to the unique and complex nature of the deep-sea environment, these experiments are extremely costly and risky, making substantial progress difficult. Therefore, a test device that can effectively simulate the seabed environment is needed. Because most deep-sea polymetallic nodule mining areas are located in ocean basins, the bottom currents in these areas differ from typical fluids in that they are laminar (Reynolds number Re < 2300) with velocities ranging from 0.01 to 0.1 m / s. Existing simulation devices produce turbulent flows (Reynolds number Re ≥ 2300) and struggle to replicate bottom-level flow velocities. Furthermore, due to the significant differences in the effects of turbulent and laminar flows on the stirred-up seafloor sediment, these devices struggle to effectively simulate the diffusion process of a real seafloor sediment plume. This is primarily due to the fact that existing simulation devices are mostly single-layer structures. This means that during the flow rectification process, water in the upper, middle, and lower layers vertically crosses, 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 sediments and bottom currents.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A flow straightening system includes several unit modules for straightening water flow into laminar flow. The unit modules are arranged in vertical layers. As water flows through the straightening system, the water within each layer of the unit modules does not flow vertically. The vertically layered unit modules enable comprehensive straightening of water flow from different heights. Compared to unlayered structures, this allows for more precise control of the flow at different vertical positions and prevents vertical flow between layers of water during the straightening process. This effectively straightens the water flow into laminar flow, resolving the difficulty of existing technologies in simulating laminar bottom flow. This provides more realistic flow conditions for subsequent simulations of the diffusion of sediment plumes on the seafloor.

[0007] As a further improvement of the above technical solution:

[0008] The unit module includes a buffer zone, which comprises a plurality of vertically layered buffer plates arranged in an arc or wavy shape. The arc or wavy buffer plates disperse and buffer the water flow, slowing it down and making it smoother. They also prevent rapids and eddies, which are detrimental to laminar flow, and further optimize the flow before it enters the subsequent zone, making the subsequent flow smoother, improving the laminar flow effect, and more closely resembling the stable or semi-stable state of the bottom current.

[0009] The unit module also includes a flow straightening zone located downstream of the buffer zone. The straightening zone includes a plurality of straightening plates spaced along the direction of the water flow. The straightening plates are configured as porous plates perpendicular to the direction of the water flow. The porous plate structure can meticulously organize and straighten the water flow. When the water flows through the small holes in the porous plate, it is divided into multiple small streams. These small streams interact and merge, making the flow velocity in the horizontal and vertical directions more uniform, thereby effectively arranging the water flow into laminar flow, overcoming the turbulence problem caused by simulation devices in the prior art and achieving effective simulation of seabed bottom flow laminar flow.

[0010] The unit module also includes a guide zone located downstream of the straightening zone. This zone comprises a number of vertically layered front guide plates, and a rear guide plate located downstream of the front guide plates. The front guide plates are configured in an arc or wavy shape, while the rear guide plates are configured as grid plates. The arc or wavy front guide plates provide initial guidance for the straightened water flow, directing it at a specific angle and direction for a more orderly flow. The grid plate structure of the rear guide plate further fine-tunes the water flow, ensuring consistency at different vertical positions, preventing deviations and turbulence, and ensuring stable flow into the subsequent stable zone. This provides a more stable and satisfactory flow for simulating real-world bottom currents.

[0011] The unit module also includes a stabilization zone downstream of the guide zone. This zone is configured as a bell-shaped opening with a gradually increasing inner diameter along the flow direction. This bell-shaped opening gradually reduces and stabilizes the flow velocity within the expanding space, further eliminating minor fluctuations and instabilities in the flow. This ensures a highly stable and uniform laminar flow output, meeting the requirements for simulating stable and semi-stable bottom currents and providing a more reliable flow environment for simulating the diffusion of sediment plumes.

[0012] The present invention then discloses a device for simulating seabed sediments and bottom currents, comprising a flow-generating system, the aforementioned flow-rectifying system, and an experimental pool, all interconnected in sequence. The flow-generating system propels water to generate flow, which is then rectified into laminar flow by the flow-rectifying system and then fed into the experimental pool, the bottom of which is paved with a seabed sediment simulation layer. This integrated simulation device structure enables a complete process from flow generation and rectification to simulating the seabed environment for experiments. The various systems work in tandem to effectively simulate an environment where seabed sediments, bottom currents, and external disturbances interact, enabling low-cost, low-risk laboratory research on the diffusion process of seabed sediment plumes, compensating for the high costs and risks of field experiments.

[0013] As a further improvement of the above technical solution:

[0014] The flow generation system includes a sequentially connected storage tank, a water pump, and a valve. The storage tank is connected to the experimental pool, and the water level within the tank is higher than the water inlet of each pump. This arrangement allows the water level within the tank to be higher than the water inlet of the pumps, allowing gravity to facilitate smoother water flow into the pumps, reducing pump energy consumption while ensuring a stable water supply. This provides a stable water flow input to the subsequent rectification system, ensuring the continued stable operation of the entire simulation device.

[0015] Each of the water pumps is connected to each valve. By designing each pump to be connected to each valve, the flow rate and flow rate of each valve can be flexibly controlled, and the water flow state can be precisely adjusted according to experimental requirements, thereby improving the adaptability and operability of the simulation device and meeting the requirements for submarine bottom current simulation under different experimental conditions.

[0016] The valves are arranged in vertical layers, with their outlets connected to the rectifier system. These valves can individually control water flows at different heights. Combined with the rectifier system's vertically layered structure, they can more precisely regulate and organize water flows at different vertical locations, making the water flow more controllable upon entering the rectifier system and further improving the accuracy of the simulation of the laminar flow state of the submarine bottom current.

[0017] The experimental pool, facing away from the flow rectification system, is connected to the flow generation system via a number of return pipes arranged in vertical layers. These return pipes enable water flows at different heights within the experimental pool to flow back to the flow generation system, achieving water recycling and reducing water waste. This ensures the stability and continuity of the water flow within the experimental pool, allowing for extended simulation experiments and providing favorable conditions for in-depth research into the diffusion process of submarine sediment plumes.

[0018] Overall, the arrangement of unit modules allows the incoming water flow to be organized into laminar flow, which is closer to real submarine bottom currents and thus improves the simulation of the actual submarine sediment plume diffusion process. Furthermore, by arranging the unit modules in a vertical layered arrangement, with each unit module arranged horizontally, the water discharged from each unit module is located at a different height, and the water flows spread horizontally at different heights, effectively reducing mutual interference between different waterways and preventing the re-generation of turbulence and eddies. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural diagram of the rectifier system;

[0020] Figure 2 This is the flow velocity change curve before and after the rectification system treatment;

[0021] Figure 3 It is a schematic diagram of the structure of the seabed sediment and bottom current simulation device;

[0022] Figure 4 Comparison of the effects of layered and non-layered settings.

[0023] 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. Stability zone; 2. Flow-generating system; 21. Storage tank; 22. Water pump; 23. Valve; 3. Experimental pool; 4. Seabed simulation layer; 5. Return pipe. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example

[0026] like Figure 1As shown, the rectification system of this embodiment includes five horizontally arranged unit modules 11. 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. The top plate and the bottom plate are both water-impermeable plates. In the process of water flowing through the rectification system, the water in each layer of the unit modules cannot penetrate the top plate and the bottom plate, so it can only flow in the corresponding unit module 11 without generating vertical water flow. 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 a different unit module 11. The five unit modules 11 are arranged in layers vertically. The water discharged from each unit module 11 is at a different height. Because each unit module 11 is arranged horizontally, the water flows of each channel diffuse horizontally at different heights, thereby effectively reducing the mutual interference between different waterways and avoiding the re-generation of turbulence and eddies.

[0027] Specifically, the unit module 11 includes a buffer zone 111, which is located near the water inlet end of the unit module 11. The buffer zone 111 includes four layers of wavy buffer plates 1111 evenly spaced vertically. A wavy gap is formed between adjacent buffer plates 1111. As the water flows through the gap, its kinetic energy is reduced and its flow direction is restricted, thereby effectively reducing turbulence and eddies in the water flow and lowering 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 spaced apart and perpendicular to the direction of the water flow. The rectifying plates 1121 are configured as porous plates, and the aperture in the middle of the rectifying plates 1121 is larger than the aperture at the edge of the rectifying plates 1121. When the water flowing through the buffer zone 111 passes through the holes on the rectifying plates 1121, its kinetic energy is further reduced, thereby further reducing turbulence and eddies in the water flow and lowering the Reynolds number Re. The unit module 11 also includes a guide zone 113 located downstream of the rectifying zone 112. The guide zone 113 includes six front guide plates 1131 evenly spaced vertically. Adjacent front guide plates 1131 form a wavy gap. As the water flows through this gap, its kinetic energy is dissipated and its flow direction is restricted, thereby effectively reducing turbulence and eddies in the water flow and lowering the Reynolds number Re. The guide zone 113 also includes a grid-like rear guide plate 1132 located downstream of the front guide plates 1131. As the water flows through the gaps between the front guide plates 1131 through the holes in the rear guide plates 1132, its kinetic energy is further dissipated, thereby further reducing turbulence and eddies in the water flow and lowering the Reynolds number Re. The unit module 11 also includes a stabilization zone 114 located downstream of the guide zone 113. The stabilization zone 114 is configured as a bell-shaped mouth with an inner diameter that gradually increases along the direction of water flow. The stabilization zones 114 of adjacent unit modules 11 are aligned. The water flowing through the guide area 113 further eliminates turbulence and eddies 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.

[0028] Electromagnetic single-point flowmeters were installed at valve 23 and in the stabilization zone 114, respectively. Both electromagnetic single-point flowmeters were placed on the same horizontal plane to monitor flow velocity changes in real time. By comparing the flow velocity data at the two locations, the gradual transition from turbulent to laminar flow can be clearly observed. Specifically, at valve 23, the flow velocity distribution exhibited significant fluctuations and irregularities, indicating that the flow was still turbulent. In contrast, at the stabilization zone 114, the flow velocity distribution became stable and uniform, with significantly reduced fluctuations, indicating that the flow had transitioned to laminar flow after being processed by the rectification system.

[0029] In order to prove that the buffer zone 111, the rectifying zone 112, the guiding zone 113 and the stabilizing zone 114 can be used to transform the turbulent flow into laminar flow, the present invention has carried out a test in the laboratory and obtained the flow velocity change at the same horizontal plane at the valve 23 and the stabilizing zone 114. Figure 2 As shown in the figure, the flow rate at valve 23 changes dramatically, with large fluctuations, exhibiting irregular fluctuations throughout the entire time period. In contrast, the flow rate at stable region 114 changes relatively smoothly, with smaller fluctuations, exhibiting a relatively stable trend throughout the entire time period. Therefore, it can be seen that after processing by the rectification system, the flow rate at stable region 114 is significantly more stable than the flow rate at valve 23. This demonstrates that the rectification system effectively reduces flow rate fluctuations and improves flow rate stability.

[0030] In addition, the Reynolds number (Re) is calculated by the formula:

[0031]

[0032] Where:

[0033]

[0034] Taking the average flow rate values of valve 23 and stable area 114 during the experiment, the Reynolds number is calculated as shown in the following table:

[0035] Table 1: Reynolds number results of two monitoring points

[0036]

[0037] The table shows that at valve 23, the Reynolds number is high, typically greater than 2300, consistent with turbulent flow. In stable zone 114, the Reynolds number drops below 2300, consistent with laminar flow. These data demonstrate that the provision of buffer zone 111, rectifying zone 112, guiding zone 113, and stable zone 114 effectively transforms turbulent flow into laminar flow, thereby enhancing the simulation of the submarine sediment plume diffusion process.

[0038] Then, if Figure 3As shown, this embodiment also discloses a device for simulating seabed sediments and bottom currents, which includes a flow-generating system 2, the aforementioned flow-rectifying system 1, and an experimental pool 3, which are sequentially connected. The flow-generating system 2 propels water to generate a flow, which is then rectified into a laminar flow by the flow-rectifying system 1 and then fed into the experimental pool 3. The bottom of the experimental pool 3 is paved with a seabed sediment simulation layer 4. The flow-rectifying system 1 includes five horizontally arranged unit modules 11. Water enters from the water inlet of the unit modules 11, is rectified by the unit modules 11 into a laminar flow, and then discharged from the water outlet. The five unit modules 11 are arranged in layers vertically. The water level of the experimental pool 3 is higher than the outlet of each unit module 11. The water discharged from each unit module 11 is located at a different height. Because each unit module 11 is arranged horizontally, the water flows diffuse horizontally at different heights within the experimental pool 3, thereby effectively reducing mutual interference between different waterways and avoiding the re-generation of turbulence and eddies. In order to prove that the effect of vertically layered unit modules is better than that of non-layered ones, 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 vertical layering. When other relevant parameters were completely consistent, the flow velocity values at 0.3m, 0.8m, and 1.2m above the ground were monitored using flow velocity sensors. The measurement results are as follows: Figure 4 As shown in the flow velocity data, the layered arrangement shows relatively stable flow at different heights, with minimal fluctuations. The unlayered arrangement exhibits significant fluctuations, particularly at higher locations. This indicates that the unlayered arrangement is unable to effectively control the flow velocity, resulting in significant fluctuations within the experimental tank. This demonstrates that the vertically layered arrangement of unit modules effectively improves flow stability, reduces interference between different waterways, and prevents the re-generation of turbulence and eddies.

[0039] 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.

[0040] Specifically, the flow generation 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 generation. The water level in the storage tank 21 is higher than the water inlet of each water pump 22, making it difficult for air to mix into the water pump 22, thereby effectively reducing the possibility of turbulence and vortexes 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 along the vertical direction, and their outlets are connected to the rectification system 1. It is difficult to achieve complete uniformity in the mechanical properties of the water pumps 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 significant differences in the various water flows generated due to performance differences of individual water pumps 22, that is, the overall stability of the water flow generated by the flow generation system 2 can be improved.

[0041] More specifically, the side of the experimental pool 3 facing away from the rectifying system 1 is connected to the flow-generating system 2 via a plurality of return pipes 5, which are arranged in vertical layers. The laminar flow discharged from the rectifying system 1 diffuses horizontally at different heights within the experimental pool 3. By arranging a plurality of return pipes 5 in vertical layers on the side of the experimental pool 3 facing away from the rectifying system 1, water from different depths within the experimental pool 3 can be simultaneously extracted, thereby reducing the vertical movement of the water to a certain extent. This effectively reduces mutual interference between different water layers and prevents the re-generation of turbulence and eddies.

[0042] 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 rate, flow rate and other indicators of the water flow in each waterway discharged through the valve 23 meet the test requirements.

[0043] Although the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, utilize the technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A device for simulating seabed sediments and bottom currents, characterized by: The invention comprises a flow-generating system (2), a flow-rectifying system (1) 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 flow-rectifying system (1) and then input into the experimental pool (3); the bottom of the experimental pool (3) is paved with a seabed sediment simulation layer (4); The rectification system (1) includes a plurality of unit modules (11) for arranging water flow into laminar flow, wherein the unit modules (11) are arranged in layers vertically, and the water level of the experimental pool (3) is higher than the water outlet of each unit module (11); when the water flows through the rectification system, the water in the unit modules (11) at each layer does not flow vertically; 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.

2. The device for simulating seabed sediments and bottom currents according to claim 1, wherein: The unit module (11) comprises a buffer zone (111), and the buffer zone (111) comprises a plurality of buffer plates (1111) arranged in layers vertically, and the buffer plates (1111) are arranged in an arc shape or a wave shape.

3. The device for simulating seabed sediment and bottom current 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 device for simulating seabed sediment and bottom current according to claim 3, characterized in that: The unit module (11) further comprises a guide zone (113) located downstream of the rectifying zone (112), the guide zone (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 or wave shape, and the rear guide plates (1132) being arranged in a grid plate.

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

6. The device for simulating seabed sediments and bottom currents according to claim 1, characterized in that: The flow generation 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 the water level in the storage tank (21) is higher than the water inlet of each water pump (22).

7. The device for simulating seabed sediments and bottom currents according to claim 6, characterized in that: Each of the water pumps (22) is connected to each valve (23).

8. The device for simulating seabed sediments and bottom currents according to claim 6, characterized in that: The valves (23) are arranged in layers vertically, and their water outlets are connected to the rectification system (1).

Images