CN118116482A - Site multi-medium model - Google Patents

Abstract

The invention provides a field multi-medium model, which comprises the following steps: the system comprises an operation module, a model framework, an input module, an activity capacity module, a temperature correction module, a transmission coefficient calculation module, a matrix construction module, a steady state solving module, a dynamic solving module and an output module. The invention simulates a relatively complex environment process by adopting the structure of the box model, solves the dependence on the actual site parameters within the acceptable range of precision loss, and combines the ordinary differential equation, thereby realizing steady-state and dynamic simulation of different sites.

Description

Site multi-medium model

Technical Field

The invention relates to the technical field of field multi-medium models, in particular to a field multi-medium model.

Background

The existing partial differential equation solving method applied to the environment under the site mostly based on space and time variability requires high-resolution environment parameters, and has the disadvantages of high data acquisition difficulty, complex operation process and limited application scene. For example, the multi-media risk assessment model 3MRA of the multi-exposure approach developed by the usa environmental protection agency USEPA and its co-office, the multi-media environmental pollutant assessment model MEPAS developed by the northwest pacific national laboratory PNNL, the multi-media pollutant return model MMSOILS developed by the usa environmental protection agency, and the like are all partial differential equations with time and space variables as independent variables as control equations, and have high calculation cost, require more specialized solving tools and specific environmental parameters, and are difficult to flexibly adapt to different sites.

Therefore, the DEFT model is totally called Dynamic Evaluative Field multimedia Transport model, is a field multi-medium model, is suitable for migration and conversion simulation of various organic pollutants in different field types and research scenes, and is compatible with dynamic and steady-state systems.

Disclosure of Invention

In view of the shortcomings in the prior art, it is an object of the present invention to provide a site multimedia model.

The field multimedia model provided by the invention comprises the following components:

And an operation module: the user defines the paths of all input files and output files, and runs the module to drive the operation of the whole model;

model frame: the method comprises the steps of constructing a field multi-medium model class and defining class functions;

an input module: reading chemical parameters and environmental parameters, and calculating environmental parameters and environmental phase volumes;

Activity and capacity calculation module: the method comprises the steps of constructing activity capacity classes and defining class functions;

and a temperature correction module: according to the activity capacity table, carrying out temperature correction on the degradation rate constant;

a transmission coefficient calculation module: calculating a transmission coefficient;

Matrix construction module: constructing a transmission matrix;

a steady state solving module: solving under the steady state condition;

And a dynamic solving module: solving the pollutant concentration in each phase under the dynamic condition by solving a normal differential equation set;

and an output module: and outputting results to obtain the concentration of the organic pollutants in the environmental phases of different areas under the steady-state and dynamic conditions.

Preferably, upon initializing the class function, the environmental parameters are read and calculated;

The model framework contains three initialization parameters: chemical parameters, environmental parameters, and emissions parameters; wherein the environmental parameters are divided into 3 files: seasonalparfile and constantparfile are used for dynamic models, STEADYPARFILE is used for steady state models; in the dynamic model, the environmental parameters that change with time are temperature, precipitation and wind speed, which are specific to each time step; emissions parameters are divided into steady state and dynamic: steady state emission data contains only grid points and phases; the dynamic emission data is specific to when and where He Xiang.

Preferably, after class function initialization, the following procedure is executed: updating chemical information; reading steady-state environment parameters, reading dynamic environment parameters and preliminary computing environment parameters; calculating B-value, correcting temperature, and calculating G-value; calculating a transmission matrix; reading emission data; the ode solver parameters are read.

Preferably, the site multi-medium model is a concentration model, the inter-phase distribution among the sub-phases in the main phase of the environment is characterized by activity capacity, and the concentration C is expressed as the product of activity capacity B and activity a: c=b·a.

Preferably, in the field multimedia model, the directly read environmental parameters are stored in the par dictionary, and the further calculated environmental parameters are stored in the par_cal dictionary.

Preferably, the construction of the activity capacity class needs to read the environmental parameters, the calculated environmental parameters and the chemical information, create a list with the length of the number of phases, simultaneously create an empty dictionary B with equal key values, traverse all the phases, store the return value of the Bi function in the dictionary B, and independently establish the function when calculating the activity capacity in each phase, thereby being convenient for editing and adjusting.

Preferably, the advection and migration flux N in each ambient phase is equal to the product of the transport coefficient G, the medium concentration c:

N＝G×c

Before calculating the G value, firstly, the parameters related to calculation and transmission need to be perfected, the transmission coefficient G _adv,ij of the i-phase to j-phase advection process, and the expression of the diffusion process G _diff,ij from the i-phase to the j-phase is as follows:

G_adv,ij＝U_ij·Area_ij

G_diff,ij＝MTC_diff,ij·Area_ij

Where U _ij is the migration rate, area _ij is the mass transfer Area of the i-th phase and the j-th phase, and MTC _diff,ij is the mass transfer coefficient in the diffusion process from the i-phase to the j-phase.

Preferably, the matrix construction module includes: in the form of a matrix, the mass emission equation becomes:

CNST＝CF·C_ss

Wherein CNST is a mass balance equation constant term matrix; CF is transmission coefficient moment, and the transmission coefficient G in the same direction is added and put into a matrix taking the number of phases as the dimension to complete the construction of the transmission coefficient matrix; c _ss is the ambient concentration vector at steady state.

Preferably, the steady state solving module comprises: after the emission data and the transmission matrix are imported, the concentration of pollutants in each phase is calculated through matrix inversion and matrix multiplication, and the solution of the mass balance equation is obtained by multiplying the left part and the right part by the inverse of the coefficient matrix because the product of the matrix and the inverse matrix is 1:

CF^-1·CF·C_ss＝CF^-1·CNST

C_ss＝CF^-1·CNST。

Preferably, the dynamic solving module includes: when in dynamic solution, the solution equation is written in a matrix form:

c(0)＝c₀

Wherein c, b, c ₀ are N-order vectors, A is an N×N matrix, and N is the number of model environmental phases; c. c0 is the concentration vector and the initial concentration vector; for vector b, in matrix a:

Where E _i is the I-th phase discharge, I _i is the I-th phase input, v _i is the I-th phase volume, and f _i,j is the I-th row, j-th column entry in the transmission coefficient matrix CF.

Compared with the prior art, the invention has the following beneficial effects:

(1) According to the invention, a relatively complex environmental process is simulated by adopting the structure of the box model, the dependence on actual site parameters is solved within an acceptable range of precision loss, and a normal differential equation is combined, so that steady-state and dynamic simulation on different sites is realized;

(2) According to the invention, the mass transfer coefficient formula of the upper and lower soil layer exchange of the box model is deduced by adopting the analytic solution of the calculation convection-dispersion equation and combining with the inter-phase distribution characterization method of the model, so that the problems of migration and conversion of pollutants in the box model in the environment phase are solved.

Drawings

Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:

FIG. 1 is a DEFT framework diagram of a venue multimedia model;

FIG. 2 is a flow chart of the DEFT operation of the venue multimedia model.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.

Examples

As shown in FIG. 1, the invention provides a field multi-medium model DEFT, which is a field multi-medium model suitable for various organic pollutants and different field types, has high-efficiency operation efficiency and rich expansibility based on a Python platform, is suitable for various organic pollutants, is suitable for different field types and research scenes, and is compatible with dynamic and steady-state systems.

The DEFT model contains a total of 10 sub-modules, including:

And the operation module is used for opening the model. The sequence of the internal operation of the model is model construction, steady state solving, steady state output, dynamic solving and dynamic output. In this module, the user needs to define paths of all input files and output files and run this module to drive the operation of the whole model.

Model framework, which is the building and class functions of the "DEFT" class. When initializing class functions, the environment parameters need to be read and calculated. The module contains three initialization parameters: chemical parameters, environmental parameters, and emissions parameters. Wherein the environmental parameters are divided into 3 files: seasonalparfile and constantparfile are used for dynamic models; STEADYPARFILE are used for steady state models. In the dynamic model, the environmental parameters that vary with time are temperature, precipitation and wind speed, which are specific to each time step. Emissions data is also divided into steady state and dynamic: steady state emission data contains only grid points and phases; the dynamic emission data is then specific to where and when He Xiang.

After class initialization, a series of functions are executed, and the specific flow is as follows: 1. updating chemical information; 2. read environment parameters (steady state), read environment parameters (dynamic), preliminary computing environment parameters. 3. Calculating B-value, correcting temperature, and calculating G-value.4. A transmission matrix is calculated. 5. Emission data is read. 6. The ode solver parameters are read.

Compared with the ideal gas partial pressure used by the traditional fugacity model as an equilibrium standard, the invention uses the activity and can simulate substances (such as metal and dissociable organic matters) which are not easy to volatilize.

DEFT is a concentration model, and the interphase distribution among all the sub interphase in the main phase of the environment is characterized by adopting activity capacity. The thermodynamic equation is expressed by using activity, namely ideal solution concentration, instead of partial pressure, so that the problem that the traditional fugacity model is difficult to treat and can be used for dissociating substances such as organic matters, metals and the like which are not easy to volatilize is solved. The concentration (C) can be expressed as the product of the activity capacity (B) and the activity (a):

C＝B·a

The input module comprises a chemical parameter reading module for reading the physicochemical parameters of the chemicals; the environment parameter reading module is used for reading parameters directly acquired in each environment phase; the environment parameter combination module is used for carrying out combination reading on parameters which are unchanged under dynamic conditions and parameters which change with time; the environment parameter calculation module is used for calculating environment parameters which cannot be directly read; the environmental phase volume calculation module is used for calculating the volume of each environmental phase in the simulation process. Although the model directly reads a portion of the environmental parameters, for some parameters it still needs to be obtained by further calculations. In the model, the directly read environmental parameters are stored in a "par" dictionary, and the further calculated environmental parameters are stored in a "par_cal" dictionary.

Activity capacity, the module is the construction of activity capacity (Bvaule) classes and definition of class functions. The Bvalue class needs to read the environment parameters, calculated environment parameters and chemical information and create a list of the number of phases in length, while creating an empty dictionary B of equal key values. And traversing all phases, storing the return value of the Bi function in the dictionary B, and independently establishing the function in each phase Bvalue during calculation, so that the editing and the adjustment are convenient.

And the temperature correction module is used for carrying out temperature correction on the degradation rate constant according to the Bvalue table.

Transmission coefficients, the module is responsible for calculating the transmission coefficients Gvalue. Advection and migration flux N (mol/s) in each ambient phase is equal to the product of the transport coefficient G (m ³/s), the medium concentration c (mol/m ³):

N＝G×c

before calculating the G value, firstly, parameters related to calculation and transmission, such as a migration rate U, a mass transfer coefficient MTC, etc., need to be perfected, and these parameters are stored in a parc dictionary. In general, the transmission coefficient G _adv,ij of the advection process from i phase to j phase, the expression of the diffusion process G _diff,ij from i phase to j phase is:

G_adv,ij＝U_ij·Area_ij

G_diff,ij＝MTC_diff,ij·Area_ij

Where U _ij is the migration rate (m/s), area _ij is the mass transfer Area of the i-th and j-th phases (m ²),MTC_diff,ij is the mass transfer coefficient (m/s) of the diffusion process from i-phase to j-phase.

After the above calculation is completed, the values corresponding to the keys in the dictionary are calculated Gdict on a process-by-process basis. The keys of Gdict dictionary are made up of a three-dimensional tuple. The first value represents the end point of the transmission, the second value represents the start point of the transmission, and the third value represents the transmission process. The phase transfer process of the contamination is determined by this three-dimensional tuple. If there are multiple transmission forms in one direction between the two phases, the first two elements in the tuple remain unchanged, and the name of the transmission process changes.

A matrix construction module, the function of which is to construct a transmission matrix. In the form of a matrix, the mass emission equation becomes:

CNST＝CF·C_ss

Wherein CNST is a mass balance equation constant term matrix, referred to herein as emissions and inputs; CF is transmission coefficient moment, and the transmission coefficient matrix is constructed by adding the transmission coefficients G in the same direction and putting the transmission coefficients G into a matrix with the number of phases as dimensions. C _ss is the ambient concentration vector at steady state.

And a steady state solving module, wherein the function of the module is to solve under a steady state condition. After the emission data and the transmission matrix are imported, the concentration of pollutants in each phase is calculated through matrix inversion and matrix multiplication. Since the product of the matrix and its inverse is 1, the solution of the mass balance equation can be obtained by multiplying the left and right parts by the inverse of the coefficient matrix:

CF^-1·CF·C_ss＝CF^-1·CNST

C_ss＝CF^-1·CNST

And the dynamic solving module is used for solving the pollutant concentration in each phase under the dynamic condition by solving a normal differential equation set. When dynamically solving, the solving equation under the matrix form can be written as:

c(0)＝c₀

Wherein c, b, c ₀ are N-order vectors, A is an N matrix, and N is the number of model environmental phases. c, c ₀ is a concentration vector and an initial concentration vector; for vector b, in matrix a:

E _i is the I-th phase discharge, I _i is the I-th phase input, v _i is the I-th phase volume, and f _i,j is the I-th row and j-th column of the transmission coefficient matrix CF.

And the output module is responsible for outputting the result and obtaining the concentration of the organic pollutants in the environmental phases of different areas under the steady state and dynamic conditions. The output file is xlsx table.

As shown in fig. 2, the model operation flow is:

1. Starting the model;

2. Initializing a model;

3. importing model parameters, including an environment parameter file and a chemical physicochemical parameter file;

4. Calculating activity capacity;

5. correcting the temperature;

6. Calculating a transmission flux;

7. constructing a transmission matrix;

8. steady state/dynamic solution; the steady state solution is: carrying out steady state solving according to a steady state input file and a steady state emission file; the dynamic solution is as follows: dynamically solving according to the time sequence input file and the time sequence emission file, and dynamically solving the initial setting according to the model initial value file, the simulation step length file and the ODE solver setting file;

9. and outputting a result to obtain a model result file.

Those skilled in the art will appreciate that the systems, apparatus, and their respective modules provided herein may be implemented entirely by logic programming of method steps such that the systems, apparatus, and their respective modules are implemented as logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc., in addition to the systems, apparatus, and their respective modules being implemented as pure computer readable program code. Therefore, the system, the apparatus, and the respective modules thereof provided by the present invention may be regarded as one hardware component, and the modules included therein for implementing various programs may also be regarded as structures within the hardware component; modules for implementing various functions may also be regarded as being either software programs for implementing the methods or structures within hardware components.

The foregoing describes specific embodiments of the present application. It is to be understood that the application is not limited to the particular embodiments described above, and that various changes or modifications may be made by those skilled in the art within the scope of the appended claims without affecting the spirit of the application. The embodiments of the application and the features of the embodiments may be combined with each other arbitrarily without conflict.

Claims (10)

1. A venue multimedia model comprising:

And an operation module: the user defines the paths of all input files and output files, and runs the module to drive the operation of the whole model;

model frame: the method comprises the steps of constructing a field multi-medium model class and defining class functions;

an input module: reading chemical parameters and environmental parameters, and calculating environmental parameters and environmental phase volumes;

Activity and capacity calculation module: the method comprises the steps of constructing activity capacity classes and defining class functions;

and a temperature correction module: according to the activity capacity table, carrying out temperature correction on the degradation rate constant;

a transmission coefficient calculation module: calculating a transmission coefficient;

Matrix construction module: constructing a transmission matrix;

a steady state solving module: solving under the steady state condition;

And a dynamic solving module: solving the pollutant concentration in each phase under the dynamic condition by solving a normal differential equation set;

and an output module: and outputting results to obtain the concentration of the organic pollutants in the environmental phases of different areas under the steady-state and dynamic conditions.

2. The site multimedia model of claim 1, wherein upon initializing class functions, the environmental parameters are read and calculated;

The model framework contains three initialization parameters: chemical parameters, environmental parameters, and emissions parameters; wherein the environmental parameters are divided into 3 files: seasonalparfile and constantparfile are used for dynamic models, STEADYPARFILE is used for steady state models; in the dynamic model, the environmental parameters that change with time are temperature, precipitation and wind speed, which are specific to each time step; emissions parameters are divided into steady state and dynamic: steady state emission data contains only grid points and phases; the dynamic emission data is specific to when and where He Xiang.

3. The site multimedia model of claim 2, wherein after class function initialization, the following procedure is performed: updating chemical information; reading steady-state environment parameters, reading dynamic environment parameters and preliminary computing environment parameters; calculating B-value, correcting temperature, and calculating G-value; calculating a transmission matrix; reading emission data; the ode solver parameters are read.

4. The site multimedia model of claim 1, wherein the site multimedia model is a concentration model, the phase-to-phase distribution of each sub-phase in the main phase of the environment is characterized by an activity capacity, and the concentration C is expressed as the product of the activity capacity B and the activity a: c=b·a.

5. The venue multimedia model according to claim 1, wherein in the venue multimedia model, the directly read environmental parameters are stored in a par dictionary and the further calculated environmental parameters are stored in a par cal dictionary.

6. The site multimedia model according to claim 1, wherein the construction of activity capacity class requires reading environmental parameters, calculated environmental parameters and chemical information, and creating a list of the number of phases of length, simultaneously creating an empty dictionary B of equal key values, traversing all phases, storing the return values of Bi functions in dictionary B, and creating functions independently of the calculation of activity capacity in each phase, facilitating editing and adjustment.

7. The field multimedia model according to claim 1, characterized in that the advection and migration flux N in each environmental phase is equal to the product of the transmission coefficient G, the medium concentration c:

N＝G×c

Before calculating the G value, firstly, the parameters related to calculation and transmission need to be perfected, the transmission coefficient G _adv,ij of the i-phase to j-phase advection process, and the expression of the diffusion process G _diff,ij from the i-phase to the j-phase is as follows:

G_adv,ij＝U_ij·Area_ij

G_diff,ij＝MTC_diff,ij·Area_ij

Where U _ij is the migration rate, area _ij is the mass transfer Area of the i-th phase and the j-th phase, and MTC _diff,ij is the mass transfer coefficient in the diffusion process from the i-phase to the j-phase.

8. The venue multimedia model of claim 1, wherein the matrix construction module comprises: in the form of a matrix, the mass emission equation becomes:

CNST＝CF·C_ss

Wherein CNST is a mass balance equation constant term matrix; CF is transmission coefficient moment, and the transmission coefficient G in the same direction is added and put into a matrix taking the number of phases as the dimension to complete the construction of the transmission coefficient matrix; c _ss is the ambient concentration vector at steady state.

9. The site multimedia model of claim 1, wherein the steady state solving module comprises: after the emission data and the transmission matrix are imported, the concentration of pollutants in each phase is calculated through matrix inversion and matrix multiplication, and the solution of the mass balance equation is obtained by multiplying the left part and the right part by the inverse of the coefficient matrix because the product of the matrix and the inverse matrix is 1:

CF^-1·CF·C_ss＝CF^-1·CNST

C_ss＝CF^-1·CNST。

10. the site multimedia model of claim 1, wherein the dynamic solution module comprises: when in dynamic solution, the solution equation is written in a matrix form:

c(0)＝c₀

Wherein c, b, c ₀ are N-order vectors, A is an N×N matrix, and N is the number of model environmental phases; c. c0 is the concentration vector and the initial concentration vector; for vector b, in matrix a:

Where E _i is the I-th phase discharge, I _i is the I-th phase input, v _i is the I-th phase volume, and f _i,j is the I-th row, j-th column entry in the transmission coefficient matrix CF.