Water quality migration and transformation simulation method, system and equipment based on multi-medium process and medium

Abstract

The invention discloses a water quality migration and transformation simulation method, system and equipment based on a multi-medium process and a medium, and relates to the technical field of water environment simulation. The method comprises the following steps: constructing a sluice control river reach water quality multiphase conversion model; the sluice-controlled river reach water quality multiphase conversion model comprises a hydrodynamic model considering a sluice scheduling effect and a water quality multiphase conversion model; wherein the hydrodynamic model is used for calculating hydrodynamic parameter values of the gate control river reach; the water quality multiphase conversion model is used for simulating a migration conversion process of water quality on a medium interface; and simulating the water quality migration and transformation process of the sluice-controlled river reach based on the sluice-controlled river reach water quality multiphase transformation model to obtain a water quality concentration temporal and spatial change result, and performing parameter calibration and verification by using the actually measured observation data of the sluice-controlled river reach. According to the invention, complex interaction and phase transformation among multiple media such as water, suspended solids, bottom mud and organisms can be comprehensively considered, and the accuracy of water quality simulation of the sluice-controlled river reach is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water environment simulation, and in particular to a water quality migration and transformation simulation method, system, equipment and medium based on a multi-media process. Background Art

[0002] The water environment in rivers, especially those regulated by sluice gates (i.e., gate-controlled sections), is highly complex. Due to the frequent opening and closing of sluice gates, the hydrological regime of the river, such as water level, flow rate, and velocity, undergoes frequent and drastic changes. This dynamic change significantly impacts the migration and transformation of pollutants in the water. Unlike natural open channels, gate-controlled sections experience more complex flow turbulence, material mixing, and interfacial exchange.

[0003] Existing water quality simulation models, such as some general river water quantity and water quality coupling models, have achieved certain results in simulating water quality changes in general rivers. However, these models often focus mainly on dissolved pollutants in the water body, or at most consider the two-phase interaction between the water body and the bottom sediment. They are usually not enough to accurately describe the complex phase transformation and interfacial transfer process of pollutants between the four main media: water, suspended matter, bottom sediment, and organisms. For example, the adsorption and desorption of dissolved pollutants by suspended matter, the sedimentation of suspended matter downstream and the resuspension of bottom sediment, and the uptake and release of pollutants by aquatic organisms will exhibit extremely complex dynamic behaviors under the drastically changing hydrodynamic conditions of the gate-controlled river section. Ignoring the interactions and transformations between these multiple phases will lead to large deviations between the simulation results and the actual situation. Especially in scenarios where it is necessary to accurately predict the changes in water quality in the gate-controlled river section, the limitations of existing technologies are particularly prominent.

[0004] Therefore, this field needs a new technical solution that can more comprehensively and accurately simulate the water quality migration and transformation process of gate-controlled river sections to overcome the shortcomings of the above-mentioned existing technologies. Summary of the Invention

[0005] The purpose of the present invention is to provide a water quality migration and transformation simulation method, system, equipment and medium based on a multi-media process, aiming to solve or improve at least one of the above-mentioned technical problems.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A water quality migration and transformation simulation method based on a multi-media process, comprising:

[0008] Constructing a multiphase transformation model for water quality in a gate-controlled river section; the multiphase transformation model includes a hydrodynamic model that considers the effects of sluice gate operation and a water quality multiphase transformation model; wherein the hydrodynamic model is used to calculate hydrodynamic parameter values ​​for the gate-controlled river section; and the multiphase transformation model is used to simulate the migration and transformation process of water quality at a medium interface; the medium interface includes water, suspended matter, sediment, and organisms.

[0009] Based on the multiphase transformation model of water quality in the gate-controlled river section, the water quality migration and transformation process of the gate-controlled river section is simulated to obtain the spatiotemporal variation results of water quality concentration, and the measured observation data of the gate-controlled river section are used for parameter calibration and verification.

[0010] Optionally, the hydrodynamic parameter values ​​include water level, flow rate and flow velocity of the gate-controlled river section.

[0011] Optionally, the hydrodynamic model simulates the river flow state of the gate-controlled river section based on the one-dimensional unsteady flow Saint-Venant equations, and uses the energy equation of the hydraulic structure to describe the discharge at the gate.

[0012] Optionally, the water quality multiphase transformation model includes at least seven water quality indicators; the water quality indicators include algae, chemical oxygen demand, dissolved oxygen, ammonia nitrogen, nitrate nitrogen, organic nitrogen and total phosphorus; wherein, the chemical oxygen demand, organic nitrogen and total phosphorus consider the spatial distribution of dissolved phase, suspended phase and sediment phase; the algae, dissolved oxygen, ammonia nitrogen and nitrate nitrogen only consider the spatial distribution of dissolved phase.

[0013] Optionally, the water quality multiphase transformation model specifically includes the following equations:

[0014] Dissolved phase equation:

[0015]

[0016] Where: C d is the concentration of dissolved phase water, mg / L; N' bd is the amount of transformation from the sediment phase to the dissolved phase under desorption, mg / (L·d); N dw is the amount of conversion from dissolved phase to suspended phase under adsorption, mg / (L·d); N db is the amount of conversion of the dissolved phase to the sediment phase under adsorption, mg / (L·d); N de N' is the amount of conversion from dissolved phase to biological phase under biological uptake, mg / (L·d); ed K1C is the amount of conversion of the biological phase to the dissolved phase under the action of biological death, mg / (L·d); N1 is the amount of material loss caused by various chemical reactions, N1=K1C d , K1 is the degradation coefficient of dissolved phase water quality, 1 / d;

[0017] Suspended phase equation:

[0018]

[0019] Where: C w is the suspended phase water concentration, mg / L; N bw N' is the amount of sediment phase converted to suspended phase under resuspension, mg / (L·d); wb is the amount of conversion of the suspended phase to the sediment phase under sedimentation, mg / (L·d); N2 is the amount of material loss caused by various chemical reactions, N2=K2C w , K2 is the degradation coefficient of suspended phase water quality, 1 / d;

[0020] Sediment phase equation:

[0021]

[0022] Where: C b is the water quality concentration of the sediment phase, g / m 2 The unit is different from the unit of dissolved phase water quality concentration mg / L. In order to unify, according to the monitoring method of sediment phase water quality, the weight of sediment per square meter is measured to convert C b Convert; N eb is the amount of transformation of the biological phase into the sediment phase due to biological death and sedimentation, mg / (L·d); N3 is the amount of material loss caused by various chemical reactions, N3 = K3C b , K3 is the degradation coefficient of sediment phase water quality, 1 / d;

[0023] Biophase equation:

[0024]

[0025] Where: C e is the biophase water quality concentration, mg / L;

[0026] Adsorption amount equation:

[0027]

[0028] Where: K xf is the adsorption coefficient, 1 / s;

[0029] Desorption amount equation:

[0030] N′ bd =K jx (C b -C d )

[0031] Where: K jx is the desorption coefficient, 1 / s;

[0032] The sedimentation-resuspension process description equation:

[0033] When sedimentation is dominant, the sedimentation amount of suspended particles G sd It is related to the settling velocity ω, the dynamic characteristics of the water body, and the sediment content S of the water body, and can be expressed as:

[0034]

[0035] Where: α represents the saturation coefficient. The settling velocity ω in still water is mainly related to the shape and particle size of the suspended particles, while in moving water it is also related to the average flow velocity of the section, salinity, and the density increment of the sediment-carrying water flow. Therefore, the settling velocity formula is first used to calculate the settling velocity ω0 of a single particle of sediment. Then, flocculation is further considered, and the influence of water flow conditions such as flow rate on settling is added to obtain the settling velocity formula for suspended particles:

[0036] ω=ru -n ω0

[0037] Where: r and n are constants.

[0038] At this time, the amount of water quality conversion as the suspended particles settle is:

[0039] N′ wb =G sd C′ w =αru -n ω0C w =K w u -n C w

[0040] Where: C′ w is the concentration of suspended phase water converted to solid phase, mg / kg; C' w =C w / S;K w is the comprehensive influence coefficient of water flow on sedimentation, K w =αrω0;

[0041] When resuspension is dominant, the amount of sediment resuspension is related to the sediment carrying capacity of the water flow. The sediment carrying capacity S* is calculated using the formula for calculating the sediment carrying capacity of the water flow, and the sediment content G lifted by the resuspension is further calculated. su ,have:

[0042] N′ wb =G sd C′ w =αru -n ω0C w =K w u -n C w

[0043] Where: k and m are constants obtained from measured data;

[0044] set up v=3m+n(m-1), then the above formula becomes G su =K S u v At this time, the water content of the resuspended sediment is:

[0045] N s =G su C b =K S u v C b

[0046] Where: K S is the resuspension coefficient; v is a constant;

[0047] The growth-death process description equation of aquatic organisms:

[0048] In the basic equation of water quality multiphase transformation, there are two terms related to the action of aquatic organisms, which are the intake of the dissolved phase by organisms, N de And the attenuation of the biological phase to the sediment phase N eb , the calculation formula is as follows:

[0049] N de =G P C e

[0050]

[0051] Where: G P 、D P 、ω P are the growth rate, mortality rate and sedimentation rate of aquatic organisms, 1 / d; D Z is the predation rate of aquatic organisms, 1 / d; Z(t) is the biomass concentration of predators, mg / L;

[0052] Taking phytoplankton as an example, the growth dynamics of phytoplankton in aquatic environment is described as:

[0053] G P =G max ×G T ×G I ×G N

[0054] Where: G max is the maximum growth rate of phytoplankton, 1 / d; G T , G I , G NThey are temperature regulation factor, light attenuation factor, and nutrient limitation factor, which are dimensionless. Among them, for biogenic substances such as nitrogen and phosphorus, G N Affected by the dissolved phase water concentration C d The impact is calculated using the following formula:

[0055]

[0056] Where: C dP 、C dN are the concentrations of dissolved inorganic phosphorus and inorganic nitrogen required for phytoplankton growth, mg / L; K mN , K mP are the half-rate coefficients of nitrogen and phosphorus, mg / L respectively.

[0057] The present invention also provides a water quality migration and transformation simulation system based on a multi-media process, comprising:

[0058] A model construction unit is used to construct a water quality multiphase transformation model for a gate-controlled river section; the water quality multiphase transformation model for the gate-controlled river section includes a hydrodynamic model that takes into account the effect of sluice operation and a water quality multiphase transformation model; wherein the hydrodynamic model is used to calculate the hydrodynamic parameter values ​​of the gate-controlled river section; the water quality multiphase transformation model is used to simulate the migration and transformation process of water quality at a medium interface; the medium interface includes water, suspended matter, sediment, and organisms;

[0059] The process simulation unit is used to simulate the water quality migration and transformation process of the gate-controlled river section based on the water quality multiphase transformation model of the gate-controlled river section, obtain the spatiotemporal change results of water quality concentration, and use the measured observation data of the gate-controlled river section to calibrate and verify parameters.

[0060] The present invention also provides an electronic device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to perform the above-mentioned water quality migration and transformation simulation method based on the multimedia process.

[0061] The present invention also provides a computer-readable storage medium, characterized in that it stores a computer program, which, when executed by a processor, implements the water quality migration and transformation simulation method based on the multimedia process as described above.

[0062] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0063] The present invention discloses a method, system, device, and medium for simulating water quality migration and transformation based on a multi-media process. The method includes constructing a multi-phase transformation model for water quality in a gate-controlled river section; the multi-phase transformation model for water quality in the gate-controlled river section includes a hydrodynamic model and a water quality multi-phase transformation model that considers the effect of sluice operation; wherein the hydrodynamic model is used to calculate the hydrodynamic parameter values ​​of the gate-controlled river section; the water quality multi-phase transformation model is used to simulate the migration and transformation process of water quality at the medium interface; based on the multi-phase transformation model for water quality in the gate-controlled river section, the water quality migration and transformation process in the gate-controlled river section is simulated to obtain the spatiotemporal variation results of water quality concentration, and the measured observation data of the gate-controlled river section is used to calibrate and verify the parameters. The present invention can comprehensively consider the complex interactions and phase transformations between multiple media such as water, suspended matter, sediment, and organisms, thereby improving the accuracy of water quality simulation in the gate-controlled river section. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0065] Figure 1 Schematic diagram of the process of the water quality migration and transformation simulation method based on the multi-media process of the present invention;

[0066] Figure 2 Schematic diagram of the phases and their mutual transformation relationships considered in the model in this embodiment. DETAILED DESCRIPTION

[0067] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0068] The purpose of the present invention is to provide a water quality migration and transformation simulation method, system, equipment and medium based on a multi-media process, aiming to solve or improve at least one of the above-mentioned technical problems.

[0069] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0070] like Figure 1 As shown, the present invention provides a water quality migration and transformation simulation method based on a multi-media process, comprising:

[0071] A multiphase transformation model of water quality in a gate-controlled river section is constructed; the multiphase transformation model of water quality in a gate-controlled river section includes a hydrodynamic model considering the effect of sluice scheduling and a water quality multiphase transformation model.

[0072] Based on the multiphase transformation model of water quality in the gate-controlled river section, the water quality migration and transformation process of the gate-controlled river section is simulated to obtain the spatiotemporal variation results of water quality concentration.

[0073] As a specific implementation, the water quality multiphase transformation model considers the migration and transformation of water quality at interfaces between water, suspended matter, sediment, and organisms. Furthermore, the hydrodynamic model is used to calculate hydrodynamic parameters such as water level, flow rate, and velocity in the gate-controlled river section, taking into account the disruptive effects of gate operation on the river's hydrodynamic processes.

[0074] The hydrodynamic model simulates the flow state of the river channel in the gate-controlled river section based on the one-dimensional unsteady flow Saint-Venant equations, and uses the energy equation of the hydraulic structure to describe the discharge at the gate. The one-dimensional unsteady flow Saint-Venant equations can be composed of differential equations describing conservation of mass and conservation of momentum.

[0075] The specific equation form of the Saint-Venant equations is as follows:

[0076]

[0077] Where: x, t are spatial coordinates and time coordinates respectively; Q, h are cross-sectional flow and water level respectively; A, R are cross-sectional flow area and hydraulic radius respectively; B s is the river width; q is the lateral inflow; C is the Xie Cai coefficient; g is the acceleration of gravity; α is the vertical velocity distribution coefficient, that is, α=A / Q 2 ∫ A u 2 dA, where u is the average flow velocity in the cross section.

[0078] As a specific implementation, the water quality multiphase transformation model comprehensively utilizes theories such as environmental hydraulics, adsorption-desorption dynamics, and aquatic organism growth dynamics to describe the physical, chemical, and biological reactions between different media such as the water body, suspended matter, sediment, and aquatic organisms. The basic equations for each water quality are as follows:

[0079] ① Dissolution phase equation:

[0080]

[0081] Where: C d is the concentration of dissolved phase water, mg / L; N' bd is the amount of transformation from the sediment phase to the dissolved phase under desorption, mg / (L·d); N dwis the amount of conversion from dissolved phase to suspended phase under adsorption, mg / (L·d); N db is the amount of conversion of the dissolved phase to the sediment phase under adsorption, mg / (L·d); N de N' is the amount of conversion from dissolved phase to biological phase under biological uptake, mg / (L·d); ed K1C is the amount of conversion of the biological phase to the dissolved phase under the action of biological death, mg / (L·d); N1 is the amount of material loss caused by various chemical reactions, N1=K1C d , K1 is the degradation coefficient of dissolved phase water quality, 1 / d.

[0082] ②Suspended phase equation:

[0083]

[0084] Where: C w is the suspended phase water concentration, mg / L; N bw N' is the amount of sediment phase converted to suspended phase under resuspension, mg / (L·d); wb It is the amount of conversion of the suspended phase to the sediment phase under sedimentation, mg / (L·d). N2 is the amount of material loss caused by various chemical reactions, N2=K2C w , K2 is the degradation coefficient of suspended phase water quality, 1 / d.

[0085] ③ Sediment phase equation:

[0086]

[0087] Where: C b is the water quality concentration of the sediment phase, g / m 2 The unit is different from the unit of dissolved phase water quality concentration mg / L. In order to unify, according to the monitoring method of sediment phase water quality, the weight of sediment per square meter is measured to convert C b Convert; N eb is the amount of transformation of the biological phase into the sediment phase due to biological death and sedimentation, mg / (L·d); N3 is the amount of material loss caused by various chemical reactions, N3 = K3C b , K3 is the degradation coefficient of sediment phase water quality, 1 / d.

[0088] ④Biological phase equation:

[0089]

[0090] Where: C e is the biophase water quality concentration, mg / L.

[0091] ⑤ Adsorption capacity equation

[0092]

[0093] Where: K xf is the adsorption coefficient, 1 / s.

[0094] ⑥Desorption amount equation

[0095] N′ bd =K jx (C b -C d )

[0096] Where: K jx is the desorption coefficient, 1 / s.

[0097] ⑦Description equation of sedimentation-resuspension process

[0098] When the sedimentation effect is dominant (i.e. the water flow velocity u is less than the stop flow velocity u z ), the sedimentation of suspended particles G sd It is related to the sedimentation velocity ω, the dynamic characteristics of the water body (expressed by the saturation coefficient α) and the sediment content S of the water body, and can be expressed as:

[0099]

[0100] Where: The settling velocity ω in still water is mainly related to the shape and particle size of suspended particles, while in moving water it is also related to the average flow velocity of the section, salinity, and density increment of the sediment-carrying water flow.

[0101] First, the settling velocity formula is used to calculate the settling velocity ω0 of a single particle of sediment. Then, the effects of flocculation and other factors are further considered, and the influence of flow conditions such as flow rate on the settling effect is added to obtain the settling velocity formula for suspended particles:

[0102] ω=ru -n ω0

[0103] Where: r and n are constants.

[0104] At this time, the amount of water quality conversion as the suspended particles settle is:

[0105] N′ wb =G sd C′ w =αru -n ω0C w =K w u -n C w

[0106] Where: C′ w is the concentration of suspended phase water converted to solid phase, mg / kg; C' w =C w / S;K wis the comprehensive influence coefficient of water flow on sedimentation, K w =αrω0.

[0107] When the resuspension effect is dominant (i.e. the water velocity u is greater than the lifting velocity u b ), the amount of sediment re-suspended is related to the sediment carrying capacity of the water flow. The sediment carrying capacity S* is calculated using the existing water flow sediment carrying capacity calculation formula, and then the sediment content G raised by the re-suspension effect is further calculated. su ,have:

[0108] N′ wb =G sd C′ w =αru -n ω0C w =K w u -n C w

[0109] Where: k and m are constants obtained from measured data.

[0110] set up v=3m+n(m-1), then the above formula becomes G su =K S u v At this time, the water content of the resuspended sediment is:

[0111] N s =G su C b =K S u v C b

[0112] Where: K S is the resuspension coefficient; v is a constant.

[0113] ⑧Description equation of the growth-death process of aquatic organisms

[0114] In the basic equation of multiphase transformation of water quality, there are two terms related to the action of aquatic organisms, namely the intake of dissolved phase by organisms N de , the attenuation of the biological phase to the sediment phase N eb , which is calculated as follows:

[0115] N de =G P C e

[0116]

[0117] Where: G P 、D P 、ω Pare the growth rate, mortality rate and sedimentation rate of aquatic organisms, 1 / d; D Z is the predation rate of aquatic organisms, 1 / d; Z(t) is the biomass concentration of predators, mg / L.

[0118] Taking phytoplankton as an example, the growth dynamics of phytoplankton in water environment can be described as:

[0119] G P =G max ×G T ×G I ×G N

[0120] Where: G max is the maximum growth rate of phytoplankton, 1 / d; G T , G I , G N They are temperature regulation factor, light attenuation factor, and nutrient limitation factor, which are dimensionless. Among them, for biogenic substances such as nitrogen and phosphorus, G N Affected by the dissolved phase water concentration C d The impact can be calculated using the following formula:

[0121]

[0122] Where: C dP 、C dN are the concentrations of dissolved inorganic phosphorus and inorganic nitrogen required for phytoplankton growth, mg / L; K mN , K mP are the half-rate coefficients of nitrogen and phosphorus respectively (i.e. the dissolved phase concentration when it is half of the saturated growth rate), mg / L.

[0123] As a specific implementation method, the water quality multiphase transformation model considers at least seven water quality indicators, including algae (PYT), chemical oxygen demand (COD), dissolved oxygen (DO), ammonia nitrogen (NH3-N), nitrate nitrogen (NO3-N), organic nitrogen (ON), and total phosphorus (TP); among which, the COD, ON, and TP consider the spatial distribution of the dissolved phase, suspended phase, and sediment phase; the PYT, DO, NH3-N, and NO3-N only consider the spatial distribution of the dissolved phase.

[0124] In one specific embodiment, the model includes basic equations describing the transport and transformation of water mass between the dissolved, suspended, and sediment phases. These basic equations include transformation terms describing mass transfer between phases. These transformation terms can reflect processes such as adsorption and desorption between the dissolved and suspended phases, sedimentation and resuspension between the suspended and sediment phases, and uptake and decomposition between organisms and the water / sediment phases.

[0125] As a specific embodiment, the model includes mathematical expressions describing the adsorption-desorption process, the sedimentation-resuspension process, and the algal growth-death process. The mathematical expression for the adsorption-desorption process can describe the amount of adsorption of the dissolved phase by suspended particles and sediment, as well as the amount of sediment desorbed into the dissolved phase; the mathematical expression for the sedimentation-resuspension process can describe the amount of sedimentation of the suspended phase into the sediment, as well as the amount of sediment resuspension into the suspended phase, taking into account the influence of the critical flow velocity of the water flow; the mathematical expression for the algal growth-death process can describe the amount of algae ingested or attenuated by the dissolved or sediment phase, taking into account factors such as temperature, light, nutrient limitation, and predation.

[0126] In this embodiment, the method further includes calibrating and validating the parameters of the water quality multiphase conversion model using measured observation data of the gate-controlled river section, wherein the measured observation data includes water quality concentration, water level, flow rate, flow velocity, etc. under different gate operation modes.

[0127] Based on the above technical solution, the following embodiments are provided.

[0128] First, a multiphase transformation model of water quality in a gate-controlled river section is constructed. The model consists of a hydrodynamic model that takes into account the effect of sluice scheduling and a water quality multiphase transformation model. The hydrodynamic model is mainly used to calculate the hydrodynamic parameter values ​​such as water level, flow rate, flow velocity, etc. in the gate-controlled river section, which is the basis for simulating the migration and diffusion of water quality. Since the gate-controlled river section is blocked and constrained by the gate, its water flow process is more complicated than that of the open channel river, and frequent and severe hydrodynamic disturbances will occur. Therefore, the hydrodynamic model needs to be able to effectively reflect these water flow characteristics, especially considering the impact of gate scheduling on the hydrodynamic process of the river. In this embodiment, the hydrodynamic model can simulate the water flow state of the river channel of the gate-controlled river section based on the one-dimensional non-steady flow Saint-Venant equations. For example, a numerical solution format that is suitable for open channel rivers and can better handle non-steady flows (such as the Abbott-Ionescu six-point implicit difference format) is used to discretely solve the Saint-Venant equations. For the discharge at the gate, the hydrodynamic model is described using the energy equation of the hydraulic structure. For example, the gate is set at the flow point of the calculation grid point (Q-point), and the energy equation of the hydraulic structure determined by the upstream and downstream water levels and the parameters of the structure itself replaces the momentum equation in the discretized Saint-Venant equations to reflect the control effect of the gate on the water flow.

[0129] The water quality multiphase transformation model is intended to describe the complex migration and transformation process of water quality components in water bodies between different media. The water quality multiphase transformation model takes into account the migration and transformation process of water quality at the interface of media such as water body (dissolved phase), suspended matter (suspended phase), sediment (sediment phase), organisms (mainly aquatic organisms, such as algae, etc.), which is a core feature that distinguishes it from traditional single or two-phase models. The water quality multiphase transformation model comprehensively utilizes theories such as environmental hydraulics, adsorption-desorption dynamics, and aquatic organism growth dynamics to describe the physical processes (such as migration, diffusion, sedimentation, and resuspension), chemical processes (such as adsorption, desorption, and degradation), and biological processes (such as growth, death, ingestion, and decomposition) of water quality between the different media.

[0130] like Figure 2 As shown, Figure 2 Schematic diagram of the phases and their mutual transformation relationships considered in the water quality multiphase transformation model in the embodiment of the present invention. Figure 2 In the water quality multiphase transformation model, at least seven water quality indicators are considered, including algae (PYT), chemical oxygen demand (COD), dissolved oxygen (DO), ammonia nitrogen (NH3-N), nitrate nitrogen (NO3-N), organic nitrogen (ON), and total phosphorus (TP). Due to their nature, the three indicators COD, ON, and TP are distributed in the dissolved phase, suspended phase, and even the sediment phase (after sedimentation) in the water body. Therefore, the model considers their transformation between these three phases and their migration within each phase. Indicators such as PYT, DO, NH3-N, and NO3-N mainly or only exist and react significantly in the dissolved phase. Therefore, the model mainly considers their spatial distribution and transformation in the dissolved phase. Figure 2 It exemplifies the material exchange and phase transformation among the water phase, suspended phase, sediment phase, biological phase, and the processes of adsorption and desorption, sedimentation and resuspension, ingestion and decomposition.

[0131] The model includes basic equations that describe the migration and transformation of water quality in the dissolved phase, suspended phase, and sediment phase. These basic equations are usually composed of basic terms that reflect the migration and diffusion of water quality within each phase with the water flow, as well as transformation terms that describe the mass transfer process between different phases. For example, the basic equation of the dissolved phase will include its advection term and diffusion term with the water flow, as well as the increase terms of desorption from the suspended phase / sediment phase, decomposition from organisms, and self-degradation, and also include loss terms of adsorption to the suspended phase / sediment phase and ingestion by organisms. The basic equations of the suspended phase and sediment phase also similarly include migration and transformation within their respective phases and transformation terms from / to other phases.

[0132] The model also includes mathematical expressions describing the adsorption-desorption process, the sedimentation-resuspension process, and the algal growth-death process. For example, the mathematical expression for the adsorption-desorption process describes the adsorption rate of dissolved pollutants by suspended particles or sediment, typically expressed as a function of the adsorption coefficient and the dissolved phase concentration; it also describes the desorption rate of sediment into the dissolved phase, expressed as a function of the desorption coefficient and the sediment phase concentration. The mathematical expression for the sedimentation-resuspension process describes the rate at which suspended pollutants settle to the water bottom with particles and the rate at which sediment-phase pollutants resuspend back into the water column with the sediment. The rates of these processes are typically related to water flow conditions (particularly the relationship between water velocity and critical flow velocity), water depth, and the sedimentation / resuspension rate coefficient. The mathematical expression for the algal growth-death process describes algal growth, death, sedimentation, and predation. For example, algal growth rate is limited by water temperature, light intensity, and the concentration of nutrients such as nitrogen and phosphorus, and affects the concentrations of dissolved oxygen, nitrogen, and phosphorus. Algal death and sedimentation also transfer pollutants to the sediment or water column. Through these mathematical expressions, the model can quantify the conversion flux of substances between different phases.

[0133] Secondly, based on the constructed multiphase transformation model for water quality in the gated river section, the water quality migration and transformation process in the gated river section is simulated to obtain the spatiotemporal variation of water quality concentration. The simulation process uses the dynamic hydrodynamic field (water level, flow rate, and flow velocity) calculated by the constructed hydrodynamic model as the input or driver of the multiphase transformation model. Then, based on the consideration of various physical, chemical, and biological processes and their interactions among multiple media, the model equations are solved numerically to calculate the temporal and spatial variation of the concentration of various water quality indicators in the dissolved, suspended, and sediment phases within the gated river section.

[0134] In one embodiment, to improve the accuracy and applicability of the model, the technology also includes calibrating and validating the parameters of the water quality multiphase transformation model using field observation data from gated river sections. This field observation data can include water concentration data monitored in different media (dissolved phase, suspended phase, and sediment phase) at different sections within the gated river section under different gate operation modes, as well as contemporaneous hydrodynamic data such as water level, flow rate, and flow velocity. Parameter calibration involves adjusting model parameters to ensure that the model simulation results match a set of field observation data as closely as possible. Parameter validation involves using the calibrated parameters to simulate another set of independent field observation data to assess the model's predictive ability and reliability. For example, the model's sensitivity can be classified based on certain parameters. Sensitive parameters can then be repeatedly adjusted and simulated within a reasonable range until the simulation results achieve a good fit with the field observation data. Insensitive parameters can be determined by reference to literature or empirical values. Ultimately, the calibrated and validated model can more accurately reflect the water quality migration and transformation patterns of a specific gated river section.

[0135] Through the above technical solution, the present invention can more comprehensively consider the unique hydrodynamic conditions of the gate-controlled river section and the complex behavior of water quality at the multi-media interface, thereby providing more accurate and reliable water quality simulation results, and providing an important scientific basis for water environment management and decision-making.

[0136] Therefore, it can be seen that this technical solution has the following beneficial effects:

[0137] By constructing a coupled model consisting of a hydrodynamic model that considers the effects of sluice gate operation and a water quality multiphase transformation model, the model comprehensively considers the complex interactions and phase transformation processes at the interfaces of multiple media, including water, suspended matter, sediment, and organisms, and includes mathematical expressions describing key processes. This model can more accurately simulate the complex conditions in sluice-controlled river sections, especially the impact of drastic hydrodynamic changes caused by frequent sluice gate operation on water quality migration and transformation. By calibrating and validating the model parameters with measured data, the model's applicability and prediction accuracy can be improved, providing scientific and effective technical support for water pollution prevention and control, water quality management, and optimization of water quality scheduling schemes in sluice-controlled river sections.

[0138] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0139] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A water quality migration and transformation simulation method based on a multi-media process, characterized in that: include: Constructing a multiphase transformation model for water quality in a gate-controlled river section; the multiphase transformation model includes a hydrodynamic model that considers the effects of sluice gate operation and a water quality multiphase transformation model; wherein the hydrodynamic model is used to calculate hydrodynamic parameter values ​​for the gate-controlled river section; and the multiphase transformation model is used to simulate the migration and transformation process of water quality at a medium interface; the medium interface includes water, suspended matter, sediment, and organisms. Based on the multiphase transformation model of water quality in the gate-controlled river section, the water quality migration and transformation process of the gate-controlled river section is simulated to obtain the spatiotemporal variation results of water quality concentration, and the measured observation data of the gate-controlled river section are used for parameter calibration and verification.

2. The water quality migration and transformation simulation method based on a multi-media process according to claim 1 is characterized in that: The hydrodynamic parameter values ​​include the water level, flow rate and flow velocity of the gate-controlled river section.

3. The water quality migration and transformation simulation method based on a multi-media process according to claim 1, characterized in that: The hydrodynamic model simulates the flow state of the river channel in the gate-controlled river section based on the one-dimensional unsteady flow Saint-Venant equations, and uses the energy equation of the hydraulic structure to describe the discharge at the gate.

4. The water quality migration and transformation simulation method based on a multi-media process according to claim 1, characterized in that: The water quality multiphase transformation model includes at least seven water quality indicators; the water quality indicators include algae, chemical oxygen demand, dissolved oxygen, ammonia nitrogen, nitrate nitrogen, organic nitrogen and total phosphorus; among them, the chemical oxygen demand, organic nitrogen and total phosphorus take into account the spatial distribution of dissolved phase, suspended phase and sediment phase; the algae, dissolved oxygen, ammonia nitrogen and nitrate nitrogen only consider the spatial distribution of dissolved phase.

5. The water quality migration and transformation simulation method based on a multi-media process according to claim 1 is characterized in that: The water quality multiphase transformation model specifically includes the following equations: Dissolved phase equation: Where: C d is the concentration of dissolved phase water, mg / L; N' bd is the amount of transformation from the sediment phase to the dissolved phase under desorption, mg / (L·d); N dw is the amount of conversion from dissolved phase to suspended phase under adsorption, mg / (L·d); N db is the amount of conversion of the dissolved phase to the sediment phase under adsorption, mg / (L·d); N de N' is the amount of conversion from dissolved phase to biological phase under biological uptake, mg / (L·d); ed K1C is the amount of conversion of the biological phase to the dissolved phase under the action of biological death, mg / (L·d); N1 is the amount of material loss caused by various chemical reactions, N1=K1C d , K1 is the degradation coefficient of dissolved phase water quality, 1 / d; Suspended phase equation: Where: C w is the suspended phase water concentration, mg / L; N bw is the amount of sediment phase converted to suspended phase under resuspension, mg / (L·d); N' wb is the amount of conversion of the suspended phase to the sediment phase under sedimentation, mg / (L·d); N2 is the amount of material loss caused by various chemical reactions, N2=K2C w , K2 is the degradation coefficient of suspended phase water quality, 1 / d; Sediment phase equation: Where: C b is the water quality concentration of the sediment phase, g / m 2 The unit is different from the unit of dissolved phase water quality concentration mg / L. In order to unify, according to the monitoring method of sediment phase water quality, the weight of sediment per square meter is measured to convert C b Convert; N eb is the amount of transformation of the biological phase into the sediment phase due to biological death and sedimentation, mg / (L·d); N3 is the amount of material loss caused by various chemical reactions, N3 = K3C b , K3 is the degradation coefficient of sediment phase water quality, 1 / d; Biophase equation: Where: C e is the biophase water quality concentration, mg / L; Adsorption amount equation: Where: K xf is the adsorption coefficient, 1 / s; Desorption amount equation: N′ bd =K jx (C b -C d ) Where: K jx is the desorption coefficient, 1 / s; The sedimentation-resuspension process description equation: When sedimentation is dominant, the sedimentation amount of suspended particles G sd It is related to the settling velocity ω, the dynamic characteristics of the water body, and the sediment content S of the water body, and can be expressed as: Where: α represents the saturation coefficient. The settling velocity ω in still water is mainly related to the shape and particle size of the suspended particles, while in moving water it is also related to the average flow velocity of the section, salinity, and the density increment of the sediment-carrying water flow. Therefore, the settling velocity formula is first used to calculate the settling velocity ω0 of a single particle of sediment. Then, flocculation is further considered, and the influence of water flow conditions such as flow rate on settling is added to obtain the settling velocity formula for suspended particles: ω=ru -n oh0 Where: r and n are constants. At this time, the amount of water quality conversion as the suspended particles settle is: N′ wb =G sd C′ w =αru -n ω0C w =K w u -n C w Where: C′ w is the concentration of suspended phase water converted to solid phase, mg / kg; C' w =C w / S;K w is the comprehensive influence coefficient of water flow on sedimentation, K w =αrω0; When resuspension is dominant, the amount of sediment resuspended is related to the sediment carrying capacity of the water flow. The sediment carrying capacity S* is calculated using the formula for calculating the sediment carrying capacity of the water flow, and the sediment content G lifted by the resuspension is further calculated. su ,have: N′ wb =G sd C′ w =αru -n ω0C w =K w u -n C w Where: k and m are constants obtained from measured data; set up v=3m+n(m-1), then the above formula becomes G su =K S u v At this time, the water content of the resuspended sediment is: N s =G su C b =K S u v C b Where: K S is the resuspension coefficient; v is a constant; The growth-death process description equation of aquatic organisms: In the basic equation of water quality multiphase transformation, there are two terms related to the action of aquatic organisms, which are the intake of the dissolved phase by organisms, N de and the attenuation of the biomass phase to the sediment phase, N eb , the calculation formula is as follows: N de =G P C e Where: G P 、D P 、ω P are the growth rate, mortality rate and sedimentation rate of aquatic organisms, 1 / d; D Z is the predation rate of aquatic organisms, 1 / d; Z(t) is the biomass concentration of predators, mg / L; Taking phytoplankton as an example, the growth dynamics of phytoplankton in aquatic environment is described as: G P =G max ×G T ×G I ×G N Where: G max is the maximum growth rate of phytoplankton, 1 / d; G T , G I , G N They are temperature regulation factor, light attenuation factor, and nutrient limitation factor, which are dimensionless. Among them, for biogenic substances such as nitrogen and phosphorus, G N Affected by the dissolved phase water concentration C d The impact is calculated using the following formula: Where: C dP 、C dN are the concentrations of dissolved inorganic phosphorus and inorganic nitrogen required for phytoplankton growth, mg / L; K mN , K mP are the half-rate coefficients of nitrogen and phosphorus, mg / L respectively.

6. A water quality migration and transformation simulation system based on a multi-media process, characterized in that: include: A model construction unit is used to construct a water quality multiphase transformation model for a gate-controlled river section; the water quality multiphase transformation model for the gate-controlled river section includes a hydrodynamic model that takes into account the effect of sluice operation and a water quality multiphase transformation model; wherein the hydrodynamic model is used to calculate the hydrodynamic parameter values ​​of the gate-controlled river section; the water quality multiphase transformation model is used to simulate the migration and transformation process of water quality at a medium interface; the medium interface includes water, suspended matter, sediment, and organisms; The process simulation unit is used to simulate the water quality migration and transformation process of the gate-controlled river section based on the water quality multiphase transformation model of the gate-controlled river section, obtain the spatiotemporal change results of water quality concentration, and use the measured observation data of the gate-controlled river section to calibrate and verify parameters.

7. An electronic device, characterized in that: It includes a memory and a processor, the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to perform the water quality migration and transformation simulation method based on a multimedia process according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that It stores a computer program, which, when executed by a processor, implements the water quality migration and transformation simulation method based on a multimedia process as described in any one of claims 1 to 5.

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