Method for predicting movement trajectory of marine pollutants and warning of water intake safety of coastal power plants

Abstract

The present invention discloses a method for predicting the movement trajectory of marine pollutants and warning the safety of water intake in coastal power plants, comprising the following steps: (1) establishing a regional tidal current mathematical model; (2) establishing a particle tracking model; (3) taking the engineering water intake gate as the center and dividing the surrounding sea area into several particle source release points; (4) calculating the movement path of pollutants, and statistically analyzing the flux and distribution of pollutants entering the open channel; (5) making a probability cloud map of pollutants entering the open channel; (6) synchronously marking the pollutants on site; (7) inputting the pollutant information into the particle tracking model to predict the subsequent movement trajectory of the pollutant and calculate the time for it to move to the water intake, so as to give a warning to the operation unit of the coastal power plant. The adoption of the above technical solution can give a warning to the cold source safety department of the coastal power plant, reduce the risk of unit shutdown caused by pollutant accumulation in the coastal power plant, and improve the operation efficiency of the coastal power plant.

Description

Technical Field

[0001] The present invention belongs to the technical field of coastal power plant protection, and particularly relates to a method for predicting the movement trajectory of marine pollutants and warning of the water intake safety of coastal power plants. Background Art

[0002] In recent years, incidents of marine organisms or foreign objects affecting the water intake safety of coastal power plants have occurred many times at home and abroad, and there is an increasing trend. The safety of the cold source has become an important factor affecting the safety of coastal power plants. According to the analysis of the World Association of Nuclear Operators (WANO), about 20% of such incidents have a direct impact on safety-related systems. In extreme cases such as a large aggregation of marine organisms or a sudden influx of pollutants, accidents such as the damage of the trash rack structure and the shutdown of the unit seriously affect the water intake safety of coastal power plants.

[0003] Due to the variety of pollutants and limited by scientific prediction means, the current main way to deal with pollutants is the passive cleaning method, that is, when under the action of tidal current and cold source water intake, pollutants accumulate on each trash rack at the water intake gate, and then are fished by manual labor. For the daily operation period, regular maintenance can ensure the safe operation of the power plant. However, in extreme cases, after a large amount of pollutants suddenly enter the water intake gate, due to the fact that human and material resources cannot meet the requirements of pollutant cleaning in a short time, a large amount of pollutants accumulate, resulting in the damage of the trash rack structure or serious blockage of the trash rack, affecting water intake, and further causing the shutdown of the power plant and affecting the operation efficiency of the power plant.

[0004] The movement of marine pollutants is comprehensively affected by tidal current, wind force and cold source water intake. For a specific area, the tidal current has periodic characteristics. Therefore, under the condition of mastering the tidal current and water intake characteristics of the area, the movement trajectory of pollutants can be analyzed and predicted. Thus, combined with on-site monitoring, the time when pollutants reach the water intake gate can be calculated, providing effective warning information for the operation unit of the coastal power plant, and thus providing effective technical support for the disaster prevention and reduction work of the coastal power plant. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for predicting the movement trajectory of marine pollutants and warning of the water intake safety of coastal power plants.

[0006] The present invention is realized as follows. A method for predicting the movement trajectory of marine pollutants and warning of the water intake safety of coastal power plants is characterized by including the following steps:

[0007] (1)Establish a tidal current mathematical model: First, according to the characteristics of the project area, establish a large-scale tidal current mathematical model. The offshore boundary is 50 - 100 km away from the project location. The mathematical model is based on the incompressibility of fluids and the Navier-Stokes equations, and obeys the Boussinesq assumption and the hydrostatic pressure assumption. Use the tidal prediction software Chinatide to provide tidal level boundary data, and verify it through the measured hydrological data to ensure the effectiveness of various parameters of the mathematical model in the project sea area and ensure the accuracy of the tidal current mathematical model.

[0008] (2)Establish a particle tracking model: Generalize the floating pollutants that enter the open channel in a discrete state, without the ability of self-swimming or with weak self-swimming ability as particles in the mathematical model. The particle tracking model uses the Langevin equation to describe the migration motion of particles.

[0009] (3)Determine the particle source release points: With the project water intake as the center, set several particle source release points in the surrounding sea area according to the distance and azimuth.

[0010] (4)Statistically analyze the flux and distribution of particles: According to the tidal current mathematical model and the particle tracking model, calculate the movement trajectories of particles under the action of tidal current and open channel water intake after releasing pollutants at different points at different times and different tidal types, and statistically analyze the flux and distribution of particles passing through the position of the trash rack at the water intake. At this time, the prediction of the movement trajectory of pollutants is completed.

[0011] (5)Create a probability cloud map: According to the statistical results, create a probability cloud map of pollutants entering the open channel, and evaluate the impact of pollutants on water intake safety. Through the probability cloud map, the risk level of the pollutant source direction can be determined, and key monitoring of this direction can be strengthened. By improving the performance of the observation equipment, the monitoring range and distance are farther, and the time for reserving countermeasures is provided.

[0012] (6)Real-time monitoring and marking: Conduct real-time monitoring of pollutants on-site, and promptly mark the pollutants that have entered the observation range of the project area, and master their positions, azimuths, and times from the water intake.

[0013] (7)Predict the subsequent movement trajectories of the marked particles: Input the information of the marked particles into the particle tracking model, calculate through the particle tracking model, predict the subsequent movement trajectories of the marked particles and calculate the time to the water intake, and give early warnings to the project operation unit to take emergency measures in a timely manner, including deploying personnel and equipment in advance to improve the cleaning ability, or selecting different salvage plans according to the type of pollutants.

[0014] Preferably, the measured hydrological data in step 1 mainly includes tidal level, flow velocity, and flow direction data.

[0015] Preferably, the objects with no or weak self-swimming ability in step 2 include one or more of foam, straw, branches, plastics, and waterweeds.

[0016] Preferably, in step 3, centering on the engineering water intake, a particle release point is set every 1 km within a range of 10 km, and the direction is 22.5°.

[0017] Preferably, in step 4, calculate the movement of pollutants released at different positions at the moments of flood peak, flood stop, ebb peak, and ebb stop.

[0018] Advantages and technical effects of the present invention: By establishing a numerical model of pollutant movement in the sea area of a coastal power plant, and by statistically analyzing the probability of pollutants entering the water intake, the key monitoring range and direction of pollutants are proposed, providing guidance for on-site monitoring. By combining on-site monitoring and numerical simulation methods, the movement trajectories of pollutants already discovered in the sea area around the coastal power plant can be quickly calculated, and the time for pollutants to move to the water intake gate can be predicted, solving the problem of currently passive garbage cleaning and the inability to effectively respond to the sudden influx of pollutants, and providing early warning information for the operation department of the power plant.

[0019] Since the present invention adopts the above technical solution, the operation department of the power plant can strengthen the monitoring of key areas in the engineering sea area. After discovering a large amount of pollutants entering the key area, the emergency plan can be quickly activated in advance, emergency resources can be allocated, effectively solving the problem of the inability to clean up garbage in time when pollutants suddenly pour into the water intake, resulting in the shutdown of the unit, and improving the operation efficiency of the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flowchart of the prediction of the movement trajectory of marine pollutants and the early warning of the water intake safety of a coastal power plant according to the present invention.

[0021] Figure 2 is a topographic and grid map of the engineering scope of the application embodiment of the present invention;

[0022] Figure 3 is a tidal level verification curve graph;

[0023] Figure 4 is a flow velocity and flow direction verification curve graph;

[0024] Figure 5 is a schematic diagram of the pollutant release position;

[0025] Figure 6 is a movement trajectory graph of pollutants released at the moment of flood peak at a position 1 km away from the dike head in the WSW direction;

[0026] Figure 7 is a probability distribution graph of the flux of pollutants entering the open channel at different positions at the moment of flood peak. DETAILED DESCRIPTION OF THE INVENTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] Please refer to Figure 1 , a method for predicting the movement trajectory of marine pollutants and warning the water intake safety of coastal power plants, which is characterized by including the following steps:

[0029] (1) Establish a tidal current mathematical model: First, according to the characteristics of the project area, establish a large-scale tidal current mathematical model, with the outer sea boundary 50 - 100 km away from the project location; the mathematical model is based on the incompressibility of the fluid and the Navier-Stokes equation, and obeys the Boussinesq assumption and the hydrostatic pressure assumption; use the tidal prediction software Chinatide to provide tidal level boundary data, and verify it through hydrological measured data to ensure the effectiveness of various parameters of the mathematical model in this project sea area and ensure the accuracy of the tidal current mathematical model;

[0030] (2) Establish a particle tracking model: Generalize floating pollutants that are in a discrete state, have no self-swimming ability or weak self-swimming ability and enter the open channel as particles in the mathematical model; the particle tracking model uses the Langevin equation to describe the migration movement of the particles;

[0031] (3) Determine the particle source release points: Take the project water intake as the center, and set several particle source release points in the surrounding sea area according to distance and azimuth;

[0032] (4) Statistically analyze the flux and distribution of particles: According to the tidal current mathematical model and the particle tracking model, calculate the movement trajectories of particles under the action of tidal current and open channel water intake after releasing pollutants at different points at different times and different tidal types, and statistically analyze the flux and distribution of particles passing through the position of the trash rack at the water intake; at this time, the prediction of the movement trajectory of pollutants is completed;

[0033] (5) Make a probability cloud map: According to the statistical results, make a probability cloud map of pollutants entering the open channel, and evaluate the impact of pollutants on water intake safety. The degree of danger of the pollutant source direction can be determined through the probability cloud map, and key monitoring of this direction should be strengthened. By improving the performance of the observation equipment, the monitoring range and distance are farther, and the time for reserving countermeasures is longer;

[0034] (6) Real-time monitoring and marking: Conduct real-time monitoring of pollutants on-site, and mark the pollutants that have entered the observation range of the project area in a timely manner to master their position, azimuth and time from the water intake;

[0035] (7) Predict the subsequent movement trajectories of the marked particles: Input the information of the marked particles into the particle tracking model. Through the calculation of the particle tracking model, predict the subsequent movement trajectories of the marked particles and calculate the time to the water intake, so as to give early warnings to the engineering operation units and take emergency measures in a timely manner, including deploying personnel and equipment in advance to improve the cleaning ability, or selecting different salvage plans according to the types of pollutants.

[0036] The further technical solutions adopted by the present invention are as follows:

[0037] Preferably, the measured hydrological data in step 1 mainly includes tidal level, flow velocity, and flow direction data. The reason for selecting the above tidal level, flow velocity, and flow direction hydrological data is that through the verification of the above parameters, it can be ensured that the mathematical model can truly simulate the tidal characteristics of the engineering area, and further provide a reliable mathematical model basis for the movement simulation of particles.

[0038] Preferably, the pollutants in step 2 refer to objects with no or weak self-swimming ability, including one or more of foam, straw, branches, plastics, and waterweeds. According to the water intake safety accidents that have occurred, there are many types of such pollutants, and compared with biological pollutants with autonomous swimming ability, their water flow followability is good. Therefore, this type of pollutant can be simulated through a mathematical model.

[0039] Preferably, in step 3, centered on the water intake of the coastal power plant, a particle release point is set every 1 km within a range of 10 km, and one direction is 22.5°. The advantages of adopting this technical solution are that it discretizes and precisely defines the spatial position of the engineering sea area, providing a basis for making the probability cloud map of pollutants entering the open channel; in addition, according to the tidal characteristics of different sea areas, the probability of pollutants outside the 10 km range entering the open channel within a tidal cycle is very small. Therefore, simulating the movement of particles within 10 km can meet the needs of early warning.

[0040] Preferably, in step 4, calculate the movement conditions of pollutants released at different points at the moments of flood peak, flood stop, ebb peak, and ebb stop. Since the tidal current velocity has periodic change characteristics, the purpose of using the four moments is to discretize time and simulate the movement of particles at different times.

[0041] Specific engineering implementation examples:

[0042] (1). First, establish a tidal current mathematical model for the engineering area and verify the accuracy of the model according to the measured hydrological data;

[0043] (1.1) For a certain power plant project, first establish a tidal current mathematical model. The calculation grid is shown in Figure 2. The calculation area is about 54 km long in the north-south direction and about 76 km wide in the east-west direction, and the outer boundary reaches the -50 m isobath;

[0044] (1.2) Verify the tidal current mathematical model;

[0045] According to the measured hydrological data, mainly including tidal level, flow velocity, and flow direction data, the verification results are shown in Figure 3 and Figure 4 , it can be seen that the calculated results of tidal level, flow velocity, and flow direction are in good agreement with the measured data, meeting the requirements of the specification (Technical Specification for Simulation Test of Water Transport Engineering JTS / T 231-2021). Therefore, the model can be used for tidal current calculation in the project area.

[0046] (2) Establish a particle tracking model: The floating pollutants entering the open channel are mainly plastics, foams, and woods, etc., which are generally discrete and are generalized as particles in the mathematical model. The particle tracking model uses the Langevin equation to describe the migration movement of particles. (3)

[0048] 3.1) First, taking the project water intake as the center, divide the surrounding sea area into 16 directions, namely E, ENE, … i … ENE (each 22.5° is a direction, starting from E and rotating counterclockwise, with ENE as the end point, corresponding to i numbered from 1 to 16), as the directions where pollutants appear;

[0049] 3.2) Set several pollutant source points at different positions from the mouth of the channel in each azimuth, such as 1 km, 2 km, … j … n km;

[0050] Since the source of pollutants can only be in the water body, assuming that the area within n km around the project is all water body, then there are a total of 16n pollutant source positions above.

[0051] 3.3) The above positions can be expressed as;

[0052] Assuming the position of the water intake is (X0, Y0), the positions of each point are:

[0053] X(i, j) =

[0054] Y(i, j) =

[0055] Calculate the movement trajectories of pollutants at each position under the action of tidal current and water intake respectively. And determine the probability of pollutants at this position entering the open channel according to the following method:

[0056] (4) According to the tidal current mathematical model and the particle tracking model, calculate the movement trajectories of particles under the action of tidal current and open channel water intake after releasing pollutants at different points at different times and different tidal types, and count the flux and distribution of particles passing through the position of the trash rack at the water intake; at this time, complete the prediction of pollutant movement trajectories;

[0057] Monitor the pollutant flux of pollutants passing through the trash rack of the water intake; among them, the pollutant release lasts for 1 hour, and the accumulation of pollutants under each working condition is evaluated by the pollutant flux percentage Pp, where:

[0058] Assume that under the kth working condition, the pollutants are located at positions X(i,j) and Y(i,j). The pollution amount released by this pollution point lasts for 1 hour, the amount of pollutants released per second is pt, and the total released amount is Tp. Calculate the movement trajectory of the pollutants under this working condition and the amount of pollutants Ip entering the open channel mouth. Then, under this working condition, the proportion (probability) of pollutants entering the open channel is

[0059] Pp = Ip / Tp

[0060] Pp——Percentage of pollutant flux passing through a certain section

[0061] Ip——Pollutant flux passing through a certain section

[0062] Tp: Total amount of pollutant release

[0063] Among them, the statistical time of the pollutant flux is within 24 hours after the pollutant release moment. The schematic diagram of the pollutant release position is shown in Figure 5. In this embodiment, through model calculation, it can be intuitively seen that after the pollutants appear, their movement trajectories under the action of the tidal current and the open channel water intake. The movement trajectory after releasing particles at the moment of flood peak in the WSW direction, 1 km away from the dike head is described; specifically, see Figure 6. The dotted line in the figure represents the trajectory, the hollow circle represents the initial release position of the pollutants, and the solid circle represents the final position after 24 hours.

[0064] It can be observed from the figure that after the pollutants appear, they mainly move westward with the flood tide current. During the ebb tide period, they move eastward with the ebb tide current. Near the mouth of the channel, due to the effect of water intake, the pollutants move into the open channel and move into the open channel on the west dike side. Therefore, it can be judged that the west dike side is the pollutant accumulation area. Therefore, garbage cleaning devices should be deployed on the west dike side with emphasis and should be considered in the design.

[0065] (5)According to the statistical results under each working condition, make a probability cloud map of pollutants entering the open channel and evaluate the impact of pollutants on water intake safety; in this embodiment, according to the above calculation method, the movement of pollutants under different working conditions is recalculated, and the probability cloud map shown in Figure 7 is statistically obtained.

[0066] It can be seen from the probability cloud map that the pollutants entering the open channel are mainly in the WSW~W direction. There are large differences in the flux sizes entering the open channel at different times. Generally speaking, when the pollutants are more than 6 km away from the dike head, almost no pollutants enter the open channel within one tidal cycle. Therefore, during on-site observation, the monitoring of pollutants within 6 km in the WSW~W direction should be strengthened, and the monitoring range can be appropriately expanded according to the performance of on-site monitoring equipment.

[0067] (6)Real-time monitoring and marking: Conduct real-time monitoring of pollutants on-site, promptly mark the pollutants that have entered the observation range of the project area, and determine their positions, bearings, and times relative to the water intake.

[0068] (7)Based on the real-time monitoring of pollutants on-site, promptly record the pollutants that have entered the observation range of the project area; input the pollutant information into the particle tracking model to predict the subsequent movement trajectory of the pollutant and calculate the time to reach the water intake, and issue a warning to the operation unit of the coastal power plant so that emergency measures can be taken in a timely manner. The specific operation in this embodiment is as follows: By observing the on-site pollution situation and inputting the pollutant position and time into the mathematical model, the movement trajectory and the time to reach the open channel can be obtained, and a warning can be issued to the operation unit of the coastal power plant, which can reserve a certain amount of time for emergency management in advance and take emergency measures in a timely manner, including deploying personnel and equipment in advance to improve the cleaning ability, or selecting different salvage plans according to the type of pollutants.

[0069] Through the above technical solutions, the floating pollutants in the sea area near the water intake of the coastal power plant are marked by on-site observation, the subsequent movement trajectory is predicted, the probability of entering the open channel and the arrival time are calculated, a warning is directly issued to the cold source safety department of the coastal power plant, the risk of unit shutdown caused by pollutant accumulation in the coastal power plant is reduced, and the operation efficiency of the coastal power plant is improved.

[0070] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for predicting the movement trajectory of marine pollutants and warning the water intake safety of coastal power plants, characterized in that: It includes the following steps: (1) Establish a tidal current mathematical model: First, according to the characteristics of the engineering area, establish a large-scale tidal current mathematical model with the offshore boundary 50 - 100 km away from the engineering location; the mathematical model is based on the incompressibility of the fluid and the Navier-Stokes equations, and obeys the Boussinesq assumption and the hydrostatic pressure assumption; use the tidal prediction software Chinatide to provide tidal level boundary data, and verify it through the measured hydrological data to ensure the effectiveness of various parameters of the mathematical model in the engineering sea area and ensure the accuracy of the tidal current mathematical model; (2) Establish a particle tracking model: Generalize the floating pollutants that are in a discrete state, have no self-swimming ability or weak self-swimming ability and enter the open channel into particles in the mathematical model; the particle tracking model uses the Langevin equation to describe the migration movement of particles; (3) Determine the particle source release points: With the engineering water intake as the center, set several particle source release points in the surrounding sea area according to the distance and azimuth; (4) Statistically analyze the flux and distribution of particles: According to the tidal current mathematical model and the particle tracking model, calculate the movement trajectories of particles under the action of tidal current and open channel water intake after releasing pollutants at different points at different times and different tidal types, and statistically analyze the flux and distribution of particles passing through the position of the trash rack at the water intake; at this time, the prediction of the pollutant movement trajectory is completed; (5) Make a probability cloud map: According to the statistical results, make a probability cloud map of pollutants entering the open channel, and evaluate the impact of pollutants on water intake safety. The degree of danger of the pollutant source direction can be judged through the probability cloud map, and key attention should be paid to strengthening the monitoring in this direction, by providing the performance of the observation equipment, the monitoring range and distance, and reserving time for response measures; (6) Real-time monitoring and marking: Conduct real-time monitoring of pollutants on-site, and promptly mark the pollutants that have entered the observation range of the engineering area, and master their positions, azimuths and times from the water intake; (7) Predict the subsequent movement trajectories of the marked particles: Input the information of the marked particles into the particle tracking model, and through the calculation of the particle tracking model, predict the subsequent movement trajectories of the marked particles and calculate the time to the water intake, and give an early warning to the engineering operation unit to take emergency measures in a timely manner, including deploying personnel and equipment in advance to improve the cleaning ability, or selecting different salvage plans according to the type of pollutants.

2. The method for predicting the movement trajectory of marine pollutants and warning the water intake safety of coastal power plants according to claim 1, characterized in that: The measured hydrological data in step 1 mainly includes tidal level, flow velocity and flow direction data.

3. The method for predicting the movement trajectory of marine pollutants and warning the water intake safety of coastal power plants according to claim 1, characterized in that: The objects with no self-swimming ability or weak self-swimming ability in step 2 include one or more of foam, straw, branches, plastics and waterweeds.

4. The method for predicting the movement trajectory of marine pollutants and warning the water intake safety of coastal power plants according to claim 1, characterized in that: In step 3, with the engineering water intake as the center, set a particle release point every 1 km within a range of 10 km, and take 22.5° as one direction.

5. The method for predicting the movement trajectory of marine pollutants and warning the water intake safety of coastal power plants according to claim 1, characterized in that: In step 4, calculate the movement conditions after releasing pollutants at different points at the moment of flood peak, high tide, ebb peak and low tide.

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