A method for optimizing layout of a blowdown port based on Fluent fluid simulation

Abstract

The application provides a sewage outlet layout optimization method based on Fluent fluid simulation, comprising the following steps: S1: setting an optimization target; S2: setting a single sewage outlet at the center of the bottom of a breeding pond as a starting point for layout optimization; S3: evaluating whether the initial layout reaches the set optimization target; S4: taking the initial sewage outlet as the center, adding the same specification of sewage outlets one by one in the circumferential direction, keeping all the sewage outlets in the circumferential direction equally spaced, judging whether the new layout reaches the set optimization target according to the simulation result, and ending the optimization until a sewage outlet layout that can reach the set optimization target is found. Through the optimization of the layout and design of the sewage outlet, the application not only realizes the goal of quickly and efficiently discharging the pollutants in the breeding pond with the least number of sewage outlets, but also guarantees the cost-effectiveness, the stability of the pond structure and the breeding environment, and promotes the green and healthy development of the aquaculture industry.

Description

Technical Field

[0001] This invention relates to the field of aquaculture technology, specifically to a method for optimizing the layout of sewage outlets based on Fluent fluid simulation. Background Technology

[0002] Aquaculture, as a crucial link in the global food supply chain, plays a vital role in ensuring food safety and promoting sustainable agricultural development through its development and technological innovation. This industry involves in-depth research in biology and ecology, and also extensively integrates modern technologies such as engineering and information technology, aiming to improve production efficiency while ensuring the harmonious coexistence of aquatic product quality and the environment. Traditional and modern aquaculture models coexist in contemporary aquaculture practices. On the one hand, we see that earthen pond aquaculture still retains its natural aquaculture characteristics, using ingenious bottom drainage designs to naturally remove sediment through physical principles, reducing human interference with the aquaculture environment. On the other hand, the rise of factory-style recirculating aquaculture systems, with their efficient water treatment capabilities and environmental control advantages, has greatly increased the stocking density and output efficiency per unit area. The integration of Internet of Things (IoT) technology has made real-time water quality monitoring and precise feeding possible, driving the wave of intelligent aquaculture.

[0003] However, despite significant technological advancements, aquaculture still faces numerous challenges, particularly in the maintenance and management of the aquaculture environment. As the core area for aquatic organism growth, the aquaculture pond is crucial; if waste and uneaten feed are not effectively removed, water quality will be directly affected, threatening the health and survival rate of the farmed organisms. Existing sewage systems often rely on a single discharge outlet layout, which, while simple in construction, reveals its low sewage discharge efficiency in practical applications. Adding more discharge outlets, as a straightforward solution, can compensate for the lack of efficiency to some extent, but each outlet requires corresponding pipeline laying, maintenance costs, and potential construction and renovation expenses. Too many outlets directly increase the economic burden, affect the structural stability of the pond, and cause excessively rapid water exchange during sewage discharge, impacting water quality parameters such as water temperature and dissolved oxygen levels, negatively affecting the farmed organisms. Summary of the Invention

[0004] To address the technical challenge of improving sewage discharge efficiency while minimizing the number of discharge outlets through reasonable layout, this invention provides a sewage outlet layout optimization method based on Fluent fluid simulation. By optimizing the layout and design of sewage outlets, the goal of quickly and efficiently discharging pollutants from aquaculture ponds can be achieved with the fewest possible sewage outlets. Furthermore, cost-effectiveness, pond structure, and the stability of the aquaculture environment are ensured, thus promoting the green and healthy development of aquaculture.

[0005] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0006] A method for optimizing the layout of sewage outlets based on Fluent fluid simulation, characterized by the following steps:

[0007] S1: Set optimization goals:

[0008] The optimization goal for the layout of sewage outlets in aquaculture ponds is to ensure that the volume fraction of pollutants in the ponds can be reduced to below 0.01% within the set sewage discharge cycle by using the minimum number of sewage outlets.

[0009] S2: Initial Layout and Simulation Analysis

[0010] A single discharge outlet was set at the center of the bottom of the aquaculture pond as the starting point for layout optimization. Fluent software was used to perform fluid dynamics simulation to simulate and obtain the curve of pollutant volume fraction changing with discharge time. The specific steps are as follows:

[0011] S2.1: Based on the actual size of the aquaculture pond, the actual location and size of the inlet, the actual location and size of the outlet, and the actual aquaculture area, a three-dimensional model of the aquaculture pond is established using three-dimensional modeling software, and the aquaculture area is defined as a fluid domain.

[0012] S2.2: Import the 3D model of the aquaculture pond into Fluent software and perform structured mesh generation on the fluid domain;

[0013] S2.3: Select the solver and solution method;

[0014] S2.4: Select the turbulence model and set the boundary conditions and physical properties of the fluid domain;

[0015] S2.5: Initialize the boundary and set the computation time step and iteration step number of the Fluent solver, then perform the computation;

[0016] S2.6: Import the calculation results into CFD-post for visualization processing to obtain the curve of the volume fraction of pollutants in the aquaculture pond changing with the discharge time;

[0017] S3: Evaluate the initial layout effect:

[0018] Based on the simulation results, determine whether the initial sewage outlet layout has achieved the set optimization target. If it has, then the initial sewage outlet layout is confirmed as the optimal solution and the optimization process ends; if it has not, proceed to the next optimization step.

[0019] S4: Multiple optimizations to the initial layout:

[0020] Using the initial sewage outlet as the center, add sewage outlets of the same specification one by one along its circumference, and keep all sewage outlets in the circumference evenly spaced. After each layout adjustment, repeat steps S2.1 to S2.6 to perform Fluent simulation on the new layout, and judge whether the new layout has achieved the set optimization goal based on the simulation results, until a sewage outlet layout that can achieve the set optimization goal is found and the optimization ends.

[0021] Furthermore, in step S1, the sewage discharge cycle is 40-60 seconds.

[0022] Furthermore, the 3D modeling software used in step S2.1 is 3D CAD software.

[0023] Furthermore, in step S2.2, the structured mesh division method is as follows: using tetrahedral or hexahedral mesh division, the mesh is densified at the water inlet and sewage outlet, and sparsely divided in other areas, and mesh independence is verified.

[0024] Furthermore, in step S2.3, the solver type is a pressure-based solver or a density-based solver.

[0025] Further, in step S2.4, the turbulence model is a k-ε model or a k-ω model; the boundary conditions include the flow velocity, pressure and flow rate at the inlet, the flow velocity, pressure and flow rate at the outlet, and the pollutant concentration and discharge method in the aquaculture pond, wherein the discharge method is continuous discharge or intermittent discharge; the physical properties of the fluid domain include density and viscosity.

[0026] Furthermore, in step S4, the distance between the initial sewage outlet and its circumferential sewage outlet is D, the diameter of the sewage outlet is d, and d≤D≤2d is satisfied.

[0027] Furthermore, the radius r of the sewage outlet satisfies 5cm≤r≤10cm.

[0028] The optimization principle of the sewage outlet layout in this invention is as follows: an iterative design strategy guided by Fluent fluid dynamics simulation technology aims to achieve the goal of efficiently purifying aquaculture pond water. Specifically, the method begins with a basic layout of a central sewage outlet, and then gradually adds sewage outlets in the circumferential direction based on the pollutant volume fraction change curve. After each adjustment, the optimization effect is verified using Fluent simulation software until the optimization target of reducing the pollutant volume fraction in the aquaculture pond to below 0.01% within a specified sewage discharge time is achieved. When the central sewage outlet pumps, a low-pressure zone is formed around it, prompting water to flow towards the center. The circumferential sewage outlets further guide the water flow, creating a circular flow along the circumference while the water flows towards the center. This layout can create more complex fluid dynamic effects. The central sewage outlet, as the main outlet, and the circumferential sewage outlets, as auxiliary outlets, work together to form eddies and circulating flow in the water, thereby enhancing the mixing and flow within the water body, facilitating the mixing and diffusion of pollutants with the water, accelerating the purification process, improving sewage discharge efficiency, and reducing environmental impact. Meanwhile, through precise simulation analysis and gradual optimization, unnecessary sewage outlets were avoided, thereby minimizing construction and maintenance costs while ensuring purification effectiveness. This innovative solution undoubtedly provides an advanced, economical, and practical solution for the sustainable development of aquaculture.

[0029] The beneficial effects of this invention are as follows:

[0030] 1. This invention, through precise fluid dynamics simulation and layout optimization, can significantly improve the discharge speed and efficiency of pollutants, ensuring that the aquaculture pond reaches an extremely low pollution level in a short time. This is beneficial for maintaining a good aquaculture environment, reducing the risk of disease transmission, and improving the growth quality and yield of aquaculture organisms.

[0031] 2. This invention, through meticulous simulation analysis and intelligent iterative design, achieves the set purification target with a minimum number of discharge outlets. This not only directly reduces the resource consumption for construction and maintenance but also fully considers the stability and safety of the pool structure, avoiding structural stress concentration, increased leakage risk, and overall structural instability that may result from adding too many discharge outlets. Furthermore, by optimizing the layout of the discharge outlets, this invention effectively controls the water exchange rate, preventing drastic fluctuations in key water quality parameters such as water temperature and dissolved oxygen levels caused by excessively rapid water circulation. This creates a more stable and suitable growth environment for aquaculture organisms, avoiding the adverse effects of sudden environmental changes on their health and growth potential.

[0032] 3. This invention uses the initial sewage outlet as the center and sets n sewage outlets of the same specification evenly in the circumferential direction to achieve the synergistic effect between water flows, forming an effective eddy mixing mechanism, which accelerates the mixing and diffusion process of pollutants with water, so that pollutants can be diluted and removed more quickly, thereby shortening the time of the entire sewage discharge process.

[0033] 4. This invention can flexibly adjust the number and layout of sewage outlets according to the specific conditions of different aquaculture ponds (such as size, shape, water flow characteristics, etc.), and has high adaptability and scalability, making it suitable for aquaculture facilities of various scales and types.

[0034] 5. This invention provides scientific evidence based on data and simulation, helping managers make more accurate decisions on sewage system design, avoiding the blindness and limitations of traditional experience-based layout, and improving the scientificity and rationality of the design. Attached Figure Description

[0035] Figure 1 This is the optimal layout diagram of the sewage outlet at the bottom of the aquaculture pond according to an embodiment of the present invention.

[0036] Figure 2 This is a curve showing the change in the volume fraction of pollutants in the aquaculture pond over discharge time under the optimal discharge outlet layout described in this embodiment of the invention.

[0037] Figure 3 This is a simulation diagram of the eddy current at the sewage outlet as described in an embodiment of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0039] To verify the practical feasibility of the proposed Fluent simulation-based sewage outlet layout optimization method, this embodiment selects a representative aquaculture pond model as the research object. This pond has a rectangular structure, covering an area of ​​400 square meters, with an average water depth of 1.5 meters, exhibiting a moderate size and providing a typical environment for studying pollutant distribution and flow characteristics. Based on this specific model, guided by the optimization strategy, we first establish a baseline sewage outlet layout and then gradually adjust the location and number of sewage outlets according to feedback from Fluent simulation analysis. The success of the optimization method is evaluated by comparing the changing trends of pollutant volume fraction over time under different layouts and the improvement effect after simulation optimization at each stage.

[0040] Specifically, the sewage outlet layout optimization method based on Fluent fluid simulation described in this embodiment includes the following steps:

[0041] S1: Set optimization goals:

[0042] Within a 50-second sewage discharge cycle, by using the minimum number of sewage outlets, the volume fraction of pollutants in the aquaculture pond can be reduced to below 0.01%.

[0043] S2: Initial Layout and Simulation Analysis

[0044] A single discharge outlet was set at the center of the bottom of the aquaculture pond as the starting point for layout optimization. Fluent software was used to perform fluid dynamics simulation to simulate and obtain the curve of pollutant volume fraction changing with discharge time. The specific steps are as follows:

[0045] S2.1: Based on the actual dimensions of the aquaculture pond, the actual location and dimensions of the inlet, the actual location and dimensions of the outlet, and the actual aquaculture area, a three-dimensional model of the aquaculture pond is established using three-dimensional CAD software, and the aquaculture area is defined as a fluid domain.

[0046] S2.2: Import the 3D model of the aquaculture pond into Fluent software, perform hexahedral structured meshing on the fluid domain, refine the mesh at the inlet and outlet, sparsely mesh other areas, and verify mesh independence.

[0047] S2.3: Select the solver and solution method. In this embodiment, the pressure-based solver is selected and the SIMPLE algorithm is selected as the solution method.

[0048] S2.4: Select a turbulence model and set boundary conditions and physical properties of the fluid domain. In this embodiment, the k-ε model is selected. The boundary conditions include the flow velocity, pressure, and flow rate at the inlet and outlet, as well as the pollutant concentration and discharge method in the aquaculture pond. The discharge method is either continuous or intermittent. The physical properties of the fluid domain include density and viscosity, which are set to 998.2 kg / m³ in this embodiment. 3 And 1.002×10⁻³ Pa·s.

[0049] S2.5: Initialize the boundary and set the computation time step and iteration step number of the Fluent solver, and then perform the computation.

[0050] S2.6: Import the calculation results into CFD-post for visualization processing to obtain the curve of the volume fraction of pollutants in the aquaculture pond changing with the discharge time.

[0051] S3: Evaluate the initial layout effect:

[0052] Based on the simulation results, it was determined whether the initial sewage outlet layout had achieved the set optimization target. In this embodiment, after 50 seconds of sewage discharge under the initial sewage outlet layout, the pollutant volume fraction in the aquaculture pond only dropped to 0.1%, which did not achieve the set optimization target, and the next optimization process was initiated.

[0053] S4: Multiple optimizations to the initial layout:

[0054] Using the initial drain outlet as the center, drain outlets of the same specification are added one by one along its circumference, maintaining equal spacing between all drain outlets along the circumference. The distance between the initial drain outlet and the drain outlets along its circumference is 24cm, and the diameter of the drain outlet is 14cm. After each layout adjustment, steps S2.1 to S2.6 are repeated to perform Fluent simulation on the new layout, and the simulation results are used to determine whether the new layout has achieved the set optimization target. In this embodiment, when the total number of drain outlets is 7, the set optimization target is achieved first. Figure 1 This is a layout diagram of the sewage outlets at the bottom of the aquaculture pond when the total number of sewage outlets is 7. Figure 2 The graph shows the change in the volume fraction of pollutants in the aquaculture pond over discharge time when the total number of discharge outlets is 7. It can be seen from the graph that when the total number of discharge outlets is 7, the volume fraction of pollutants in the aquaculture pond drops to 0.005% after 50 seconds of discharge, which is less than the set optimization target of 0.01%. Therefore, it can be considered that... Figure 1 The displayed sewage outlet layout is the optimal solution.

[0055] In this embodiment, six identical sewage outlets are evenly arranged around the initial sewage outlet as the center, thereby achieving synergistic effects between water flows and forming an effective vortex discharge mechanism. Figure 3 This is a simulation diagram of the eddy current at the sewage outlet. This layout not only accelerates the centralized discharge of pollutants by using a minimum number of sewage outlets and significantly shortens the residence time of pollutants in the aquaculture environment, but also improves sewage discharge efficiency through optimized hydrodynamic design, while ensuring minimal disturbance to aquaculture organisms and the environment during the discharge process.

[0056] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for optimizing the layout of sewage outlets based on Fluent fluid simulation, characterized in that, Includes the following steps: S1: Set optimization goals: The optimization goal for the layout of sewage outlets in aquaculture ponds is to ensure that the volume fraction of pollutants in the ponds can be reduced to below 0.01% within the set sewage discharge cycle by using the minimum number of sewage outlets. S2: Initial Layout and Simulation Analysis A single discharge outlet was set at the center of the bottom of the aquaculture pond as the starting point for layout optimization. Fluent software was used to perform fluid dynamics simulation to simulate and obtain the curve of pollutant volume fraction changing with discharge time. The specific steps are as follows: S2.1: Based on the actual size of the aquaculture pond, the actual location and size of the inlet, the actual location and size of the outlet, and the actual aquaculture area, a three-dimensional model of the aquaculture pond is established using three-dimensional modeling software, and the aquaculture area is defined as a fluid domain. S2.2: Import the 3D model of the aquaculture pond into Fluent software and perform structured mesh generation on the fluid domain; S2.3: Select the solver and solution method; S2.4: Select the turbulence model and set the boundary conditions and physical properties of the fluid domain; S2.5: Initialize the boundary and set the computation time step and iteration step number of the Fluent solver, then perform the computation; S2.6: Import the calculation results into CFD-post for visualization processing to obtain the curve of the volume fraction of pollutants in the aquaculture pond changing with the discharge time; S3: Evaluate the initial layout effect: Based on the simulation results, determine whether the initial sewage outlet layout has achieved the set optimization target. If it has, then the initial sewage outlet layout is confirmed as the optimal solution and the optimization process ends; if it has not, proceed to the next optimization step. S4: Multiple optimizations to the initial layout: Using the initial sewage outlet as the center, add sewage outlets of the same specification one by one along its circumference, and keep all sewage outlets in the circumference evenly spaced. After each layout adjustment, repeat steps S2.1 to S2.6 to perform Fluent simulation on the new layout, and judge whether the new layout has achieved the set optimization goal based on the simulation results, until a sewage outlet layout that can achieve the set optimization goal is found and the optimization ends.

2. The method for optimizing the layout of sewage outlets based on Fluent fluid simulation according to claim 1, characterized in that, In step S1, the sewage discharge cycle is 40-60 seconds.

3. The method for optimizing the layout of sewage outlets based on Fluent fluid simulation according to claim 1, characterized in that, The 3D modeling software used in step S2.1 is 3D CAD software.

4. The method for optimizing the layout of sewage outlets based on Fluent fluid simulation according to claim 1, characterized in that, In step S2.2, the structured mesh division method is as follows: using tetrahedral or hexahedral mesh division, the mesh is densified at the water inlet and sewage outlet, and sparse mesh division is performed in other areas, and mesh independence is verified.

5. The method for optimizing the layout of sewage outlets based on Fluent fluid simulation according to claim 1, characterized in that, In step S2.3, the solver type is a pressure-based solver or a density-based solver.

6. The method for optimizing the layout of sewage outlets based on Fluent fluid simulation according to claim 1, characterized in that, In step S2.4, the turbulence model is a k-ε model or a k-ω model; the boundary conditions include the flow velocity, pressure and flow rate at the inlet, the flow velocity, pressure and flow rate at the outlet, and the pollutant concentration and discharge method in the aquaculture pond, wherein the discharge method is continuous discharge or intermittent discharge; the physical properties of the fluid domain include density and viscosity.

7. The method for optimizing the layout of sewage outlets based on Fluent fluid simulation according to claim 1, characterized in that, In step S4, the distance between the initial sewage outlet and the sewage outlet in the circumferential direction is D, the diameter of the sewage outlet is d, and d≤D≤2d is satisfied.

8. The method for optimizing the layout of sewage outlets based on Fluent fluid simulation according to claim 7, characterized in that, The radius r of the sewage outlet satisfies 5cm≤r≤10cm.

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