Disclosure of Invention
The invention provides a sewage deep sea optimized discharge response relation based on tidal current change for solving the technical problems in the known technology, the sewage discharge amount controlled by adopting the response relation can be optimized and adjusted in real time along with the motion of complex tidal waves, so that the sewage is highly diluted in a space-time range as small as possible, the initial dilution effect is improved, and the sewage finally reaches the standard and is discharged.
The technical scheme adopted by the invention for solving the technical problems in the prior art is as follows: a sewage deep sea optimized discharge response relation determination method based on tidal current change comprises the following steps:
1) calculating the engineering sea area load flow change interval (u) by adopting a simulation inverse algorithmmin,u1,…,ui,…,un,umax) Middle n +2 tidal flow velocities and optimal sewage discharge (Q) corresponding to the samemin,Q1,…,Qi,…,Qn,Qmax) The method comprises the following specific steps:
1.1) establishing a simulation back calculation method model
1.1.1) adopting a sewage outlet pollutant diffusion mathematical model;
1.1.2) establishing a Multi-objective function
MAX.DD=C0/C1 (1)
MIN.EC=0.0414×Q+13.828 (2)
MAX.OE=OE (3)
In the formula (1), DD is the dilution of pollutants; c0The concentration value of the pollutants in the jet flow water body is obtained; c1The concentration value of the pollutant at a certain point in the environmental water body is obtained; EC is energy consumption value; q is the sewage discharge amount of the pump, m is m multiplied by v multiplied by S, m is the number of the nozzles, v is the discharge rate, and S is the sectional area of the nozzles; OE is the sewage discharge efficiency;
1.1.3) Using a genetic Algorithm model
1.1.3.1) using evolutionary computation operators
1.1.3.2) using cross-computing operators
1.1.3.3) calculation operator by mutation
1.2) initial setting
1.2.1) taking the sewage discharge as a control variable of an optimization process, and adopting a real number coding form;
1.2.2) setting a value range of the control variable, and taking the value range as a constraint condition of the genetic algorithm population value;
1.3) for the engineering sea area tidal current change interval (u)min,u1,…,ui,…,un,umax) The simulation reverse calculation of the optimal sewage discharge amount is carried out according to the following steps for each tidal current flow velocity, and then n +2 optimal sewage discharge amounts (Q) aiming at n +2 tidal current flow velocities can be obtainedmin,Q1,…,Qi,…,Qn,Qmax)
1.3.1) randomly selecting r numerical values in a control variable value range according to each tidal current flow rate to obtain r chromosomes, and forming a population (r) of possible solutions of the optimal sewage discharge amount under the tidal current flow rate condition;
1.3.2) taking each chromosome as a numerical example, adopting a pollutant diffusion mathematical model of a sewage outlet to calculate r times, and simultaneously outputting and storing r pollutant concentration results of observation points in a water area;
1.3.3) carrying out chromosome evaluation by adopting the multi-target function established in the step 1.1.2) with the target of optimal sewage dilution effect, lowest energy consumption and optimal sewage discharge efficiency;
1.3.4) when the maximum generation number is met, jumping out of the program and outputting the best chromosome, namely the optimal sewage discharge amount; if the maximum generation number target is not met, adopting the genetic algorithm model in the step 1.1.3) to perform genetic calculation;
1.3.5) updating the chromosomes selected in the step 1.3.1) through genetic calculation, obtaining a brand new population, and repeating the calculation according to the steps (1.3.2) to (1.3.4) until the best chromosomes, namely the best sewage discharge amount, is output;
2) establishing a data-driven BP algorithm model of the artificial neural network, wherein a hyperbolic Sigmoid function is adopted as a nonlinear conversion function in the BP algorithm model of the artificial neural network, and the formula (9) is as follows:
f(x)=1/1+e-x+θ (9)
in the formula, theta represents a threshold value;
in the artificial neural network BP algorithm model, Root Mean Square Error (RMSE) is adopted to evaluate the prediction capability of the network, and the formula (10) shows:
in the formula, a is the number of data; y isiIs an actual measurement value; y isi' is a predicted value;
the normalization processing of all data in the artificial neural network BP algorithm model adopts an equation (11):
wherein:
represents a normalized value; y is
iRepresents the value before normalization; y is
maxRepresents the maximum of all data; y is
minRepresents the minimum of all data;
3) initializing network weight and combining with engineering sea area tidal current change interval (u)min,u1,…,ui,…,un,umax) Middle n +2 tidal flow velocities and optimal sewage discharge (Q) corresponding to the samemin,Q1,…,Qi,…,Qn,Qmax) Setting a network architecture and setting basic parameters of an artificial neural network BP algorithm model;
4) taking n +2 tidal current flow rate data as the input of an artificial neural network BP algorithm model, correspondingly taking n +2 optimal sewage discharge amount as the output of the artificial neural network BP algorithm model, substituting the optimal sewage discharge amount into the artificial neural network model for training and learning, and calculating the root mean square error;
5) when the error requirement of Root Mean Square Error (RMSE) is met, a jump-out program establishes a response relation; if the Root Mean Square Error (RMSE) error requirement is not met, performing subsequent calculation;
6) and (4) based on the root mean square error, after the network weight is reversely adjusted, repeating the calculation according to the steps 3) -5) until a response relation is established.
The invention has the advantages and positive effects that: by taking the optimal sewage dilution effect, the lowest energy consumption and the optimal sewage discharge efficiency as targets, the response relation between the flow speed in the tidal current change interval of the engineering sea area and the optimal sewage discharge amount corresponding to the flow speed is established, the response relation is applied, the deep sea sewage discharge amount is optimized and adjusted in real time, the sewage can be highly diluted in a space-time range as small as possible, the initial dilution effect is improved, the sewage can be finally discharged up to the standard, the management level of the deep sea sewage discharge can be improved, and the ecological quality level of the sea area environment is maintained.
Detailed Description
To further understand the contents, features and effects of the present invention, the following examples are illustrated as follows:
a sewage deep sea optimized discharge response relation determination method based on tidal current change comprises the following steps:
1) calculating the engineering sea area load flow change interval (u) by adopting a simulation inverse algorithmmin,u1,…,ui,…,un,umax) Middle n +2 tidal flow velocities and optimal sewage discharge (Q) corresponding to the samemin,Q1,…,Qi,…,Qn,Qmax) The method comprises the following specific steps:
1.1) establishing a simulation back calculation method model
1.1.1) the mathematical model of pollutant diffusion at sewage outlet is adopted, please refer to the following two documents, namely, Zhoufeng, Liangshuxiu, Sunschen, numerical simulation of the influence of Jet spray angle on Jet characteristics in a Flowing water environment [ J ]. university of continental Engineering, 2007,47(4): 583-.
1.1.2) establishing a Multi-objective function
MAX.DD=C0/C1 (1)
MIN.EC=0.0414×Q+13.828 (2)
MAX.OE=OE (3)
In the formula (1), DD is the dilution of pollutants; c0The concentration value of the pollutants in the jet flow water body is obtained; c1The concentration value of the pollutant at a certain point in the environmental water body is obtained; EC is energy consumption value; q is the sewage discharge amount of the pump, m is m multiplied by v multiplied by S, m is the number of the nozzles, v is the discharge rate, and S is the sectional area of the nozzles; OE is sewage discharge efficiency, and for practical engineers, the higher the efficiency, the better; the formula (2) is obtained by adopting least square fitting according to the flow and the energy consumption of the Germany KSB company K400-500 type horizontal sewage pump under different operation modes.
1.1.3) Using a genetic Algorithm model
The genetic algorithm applies the prior art, comprises three calculation parts, namely evolution, intersection and variation, and specifically comprises a genetic algorithm model:
1.1.3.1) using evolutionary computation operators
1.1.3.2) using cross-computing operators
1.1.3.3) calculation operator by mutation
The genetic algorithm comprises the following steps: evolutionary calculations (roulette selection), cross calculations (as shown in equations (4) and (5)), and variant calculations (as shown in equations (6) to (8)).
Os1=ω×Pa1+(1-ω)×Pa2 (4)
Os2=ω×Pa2+(1-ω)×Pa1 (5)
In the formulas (4) and (5), omega is a random parameter between-0.25 and 1.25; os and Pa represent offspring and father, respectively; 1 and 2 are labels of children and parents.
And (3) calculating variation:
X=X'+Δ(t,y) (6)
in the formulas (6) and (7), X is a mutated gene, X' is an initial gene, T is the current generation number, T is the maximum generation number, r is a random number between 0 and 1, and b is a system parameter. The parameter y takes the value according to the formula (8), LD is the minimum value of the gene, UD is the maximum value of the gene, and i is a random number which is 0 or 1 respectively.
1.2) initial setting
1.2.1) taking the sewage discharge amount as a control variable of an optimization process and adopting a real number coding form.
1.2.2) setting the value range of the control variable, and taking the value range as the constraint condition of the genetic algorithm population value.
1.3) for the engineering sea area tidal current change interval (u)min,u1,…,ui,…,un,umax) The simulation reverse calculation of the optimal sewage discharge amount is carried out according to the following steps for each tidal current flow velocity, and then n +2 optimal sewage discharge amounts (Q) aiming at n +2 tidal current flow velocities can be obtainedmin,Q1,…,Qi,…,Qn,Qmax) The method comprises the following specific steps:
1.3.1) randomly selecting r numerical values in the control variable value range according to each tidal current flow velocity to obtain r chromosomes, and forming a population (r) of possible solutions of the optimal sewage discharge amount under the tidal current flow velocity condition.
1.3.2) taking each chromosome as a numerical example, adopting a pollutant diffusion mathematical model to carry out r times of calculation, and simultaneously outputting and storing r pollutant concentration results of observation points in the water area.
1.3.3) carrying out chromosome evaluation by adopting the multi-objective function established in the step 1.1.2) with the goals of optimal sewage dilution effect, lowest energy consumption and optimal sewage discharge efficiency.
1.3.4) when the maximum generation number is met, jumping out of the program and outputting the best chromosome, namely the optimal sewage discharge amount; if the maximum generation number target is not met, the genetic algorithm model in the step 1.1.3) is adopted for genetic calculation.
1.3.5) updating the chromosomes selected in the step 1.3.1) through genetic calculation, obtaining a brand new population, and repeating the calculation according to the steps (1.3.2) to (1.3.4) until the best chromosomes, namely the best sewage discharge amount, is output.
The simulation inverse algorithm embeds a sewage discharge port pollutant diffusion mathematical model (also called a jet flow model) and an operation energy consumption formula into a genetic algorithm model, takes the optimal sewage dilution effect, the lowest energy consumption and the optimal discharge efficiency as targets, carries out a coupling method model of optimal sewage discharge amount simulation inverse calculation, adopts the sewage discharge port pollutant diffusion mathematical model to calculate each chromosome and outputs pollutant concentration data of an observation point in a calculated water area; calculating and analyzing the dilution, sewage conveying energy consumption and discharge efficiency of each chromosome by adopting a multi-objective function; taking the maximum generation number set by the model as a judgment condition, jumping out of a calculation program when the condition is met, and entering genetic calculation when the condition is not met; and (4) adjusting chromosomes by genetic calculation operators of evolution, intersection and variation to form a brand new population, and substituting the brand new population into a pollutant diffusion mathematical model of the sewage outlet to perform calculation of the next generation.
2) Establishing a data-driven BP algorithm model of the artificial neural network, wherein a hyperbolic Sigmoid function is adopted as a nonlinear conversion function in the BP algorithm model of the artificial neural network, and the formula (9) is as follows:
f(x)=1/1+e-x+θ (9)
in the formula, theta represents a threshold value;
in the artificial neural network BP algorithm model, Root Mean Square Error (RMSE) is adopted to evaluate the prediction capability of the network, and the formula (10) shows:
in the formula, a is the number of data; y isiIs an actual measurement value; y isi' is a predicted value.
The normalization processing of all data in the artificial neural network BP algorithm model adopts an equation (11):
wherein:
represents a normalized value; y is
iRepresents the value before normalization; y is
maxRepresents the maximum of all data; y is
minRepresents the minimum of all data.
3) Initializing network weight and combining with engineering sea area tidal current change interval (u)min,u1,…,ui,…,un,umax) Middle n +2 tidal flow velocities and optimal sewage discharge (Q) corresponding to the samemin,Q1,…,Qi,…,Qn,Qmax) Setting a network architecture and setting basic parameters of the BP algorithm model of the artificial neural network. The determination of the basic parameters can be found in the literature: research on sea area combined unit water quality model multi-parameter step-by-step coupling optimization inversion method based on data drive and genetic calculation [ J]Practice and understanding of mathematics 2015,45(12): 167-.
4) And taking n +2 tidal current flow rate data as the input of the BP algorithm model of the artificial neural network, correspondingly taking n +2 optimal sewage discharge amount as the output of the BP algorithm model of the artificial neural network, substituting the optimal sewage discharge amount into the artificial neural network model for training and learning, and calculating the root mean square error.
5) When the error requirement of Root Mean Square Error (RMSE) is met, a jump-out program establishes a response relation; if the Root Mean Square Error (RMSE) error requirement is not met, then the subsequent calculation is entered.
6) And (4) based on the root mean square error, after the network weight is reversely adjusted, repeating the calculation according to the steps 3) -5) until a response relation is established.
The response relation establishing method has the advantages that the data-driven model-artificial neural network BP algorithm is adopted, and the response relation between the system variables can be established only by taking the system state variables and the control variables as model input and output and analyzing the characteristics of the system data on the basis of little knowledge of the system physical knowledge.
While the present invention has been described in connection with the preferred embodiments thereof, it is not intended to limit the present invention to the particular embodiments described above, which are intended to be illustrative rather than limiting, and it will be apparent to those of ordinary skill in the art in light of the teachings of the present invention that many more modifications can be made without departing from the spirit and scope of the invention as defined in the appended claims.