Radiation simulation calculation method and device based on multi-physics field coupling and storage medium

Abstract

The invention discloses a radiation simulation calculation method based on multi-physics field coupling, computer equipment and a storage medium. The radiation simulation calculation method based on multi-physics field coupling is applied to the field of water treatment, the application scene is that to-be-treated water containing microorganisms flows through an ultraviolet reactor, and a light source emitting ultraviolet rays is arranged in the ultraviolet reactor. The radiation simulation calculation method based on multi-physics field coupling comprises the following steps: calculating ultraviolet light intensity distribution in a reactor; calculating fluid velocity distribution in the reactor; calculating the movement speed of the microbial particles along with the fluid based on the fluid speed distribution in the reactor to obtain the movement state of the microbial particles in the reactor; and based on the ultraviolet light intensity distribution and the motion state of the microbial particles in the reactor, calculating the total ultraviolet radiation dose of the microbial particles when the to-be-treated water flows through the ultraviolet reactor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultraviolet sterilization, and in particular to a radiation simulation calculation method based on multi-physical field coupling, a computer device and a storage medium. BACKGROUND

[0002] Ultraviolet sterilization is a commonly used water treatment technology. Accurate prediction of the flow field distribution and ultraviolet light intensity distribution of the reactor can determine the radiation dose of microorganisms in the flow field, so as to save energy input and reduce operating costs under the premise of ensuring the microorganism killing effect; and it also plays a positive guiding role in the design optimization of the reactor.

[0003] By optimizing the flow field distribution and ultraviolet energy supply, the accurate calculation of the ultraviolet radiation dose of microorganisms can be realized, thereby providing a basis for theoretically predicting the microorganism killing effect, which is of great significance for cost reduction and efficiency improvement.

[0004] After searching, the following prior art is found: The patent specification with publication number CN114323267A discloses a method for measuring the ultraviolet dose of microorganisms of an ultraviolet sterilization water purifier. The method obtains the flow trajectory of microorganisms in the ultraviolet sterilization water purifier by simulation; samples the trajectory to obtain a series of coordinate points and the time interval between two sampling points; obtains the ultraviolet irradiation intensity of each point in space by irradiation analysis, and multiplies the interval time to obtain the ultraviolet irradiation dose obtained by microorganisms during the movement between the two sampling points; according to the spatial distribution, the number of sampling points on the trajectory line and the interval of the sampling points are selected to obtain the quantitative overall effective dose. The patent technology uses simulation means to simulate the movement trajectory of microorganisms with water flow, residence time and dynamic numerical value of the ultraviolet radiation intensity.

[0005] The patent specification with publication number CN116392614A discloses a method for determining the ultraviolet sterilization effect, comprising: constructing a spatial coordinate system of a target space where an ultraviolet light source is located; determining the relative position of a target point and the ultraviolet light source based on the spatial coordinate system; the target point is any point in the target space; calculating the ultraviolet radiation intensity of the target point based on the relative position and the ultraviolet radiation intensity at the ultraviolet light source; calculating the ultraviolet radiation dose of the target point based on the ultraviolet radiation intensity of the target point; determining the ultraviolet sterilization effect of the target point according to the ultraviolet radiation dose of the target point and the relationship table of the ultraviolet radiation dose and the sterilization rate. SUMMARY

[0006] The present application provides a radiation simulation calculation method based on multi-physical field coupling, a computer device and a storage medium.

[0007] The specific technical solutions are as follows: In a first aspect, the present application provides a radiation simulation calculation method based on multi-physical field coupling, which is used in the field of water treatment and applied to the process that the water containing microorganisms to be treated flows through an ultraviolet reactor with light sources emitting ultraviolet rays in the reactor. The radiation simulation calculation method based on multi-physical field coupling comprises: calculating the ultraviolet light intensity distribution in the reactor; calculating the fluid velocity distribution in the reactor; calculating the movement speed of the microorganism particles with the fluid based on the fluid velocity distribution in the reactor to obtain the movement state of the microorganism particles in the reactor; calculating the total ultraviolet radiation dose received by the microorganism particles when the water to be treated flows through the ultraviolet reactor based on the ultraviolet light intensity distribution and the movement state of the microorganism particles in the reactor.

[0008] Further, the radiation simulation calculation method based on multi-physical field coupling calculates the ultraviolet light intensity distribution in the reactor according to the ray optics fluence rate theory, and the formula is as follows:

[0009] wherein: E0: fluence rate; t: time; V: differential volume; n: ray label; M: total number of rays; Q n : power of ray n; C n : speed of ray n.

[0010] Further, the radiation simulation calculation method based on multi-physical field coupling calculates the fluid velocity distribution in the reactor by using the RANS k-ε turbulent flow model, and the equation is as follows: continuity equation:

[0011] time-averaged equation:

[0012] transport equation of turbulent kinetic energy k:

[0013] transport equation of turbulent dissipation rate ε:

[0014] wherein: x i , x j: These represent vectors in the directions i and j, respectively; u i u j : Represents the velocity components in the i and j directions, respectively; f i : Represents the component of the mass force per unit mass in the i-direction; ρ: fluid density; t: time; p: fluid pressure; v: dynamic viscosity; k: Turbulent kinetic energy; : The average velocity in the j-direction; v t : Turbulent viscosity; σ k : The Prandtl number of turbulent kinetic energy k; σ ε The Prandtl number of the turbulent dissipation rate ε; P k The rate at which energy is transferred from the mean flow to turbulent kinetic energy; ε: Turbulent dissipation rate, the rate at which turbulent kinetic energy is converted into heat energy through viscosity; , : Empirical constant.

[0015] Furthermore, the radiation simulation calculation method based on multiphysics coupling uses the following particle tracking equation to calculate the velocity of microbial particles moving with the fluid, thereby obtaining the motion state of microbial particles in the reactor at different times:

[0016] in: q: Displacement vector of microbial particles along streamlines; t: time; u: fluid velocity; m p Microbial particle mass; F ext : The net external force vector acting on the particle; : Represents the time corresponding to the change in velocity of a particle in a fluid.

[0017] Furthermore, the radiation simulation calculation method based on multiphysics coupling provides the following formula for calculating the total radiation dose received by a microbial particle at any point on its trajectory:

[0018] E0: Injection rate; t: time; D: cumulative radiation dose of particles at any point in the reactor.

[0019] Further, the radiation simulation calculation method based on multi-physics coupling further comprises: introducing a microbial inactivation exponential decay model for predicting the proportion of inactivated and / or killed microorganisms.

[0020] Further, the microbial inactivation exponential decay model is as follows:

[0021] Wherein: N(t): represents the number or concentration of active microorganisms in the reactor at a certain time t; t: time; N0: represents the initial number or concentration of active microorganisms; k0: inactivation constant; D: cumulative dose of particles in the ultraviolet reactor.

[0022] In a second aspect, the present application provides a computer device comprising a memory and a processor, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, and the computer program runs to make the processor execute the radiation simulation calculation method based on multi-physics coupling of the first aspect.

[0023] In a third aspect, the present application provides a computer readable storage medium, the computer readable storage medium stores programs or instructions, and the programs or instructions are executed by the computer device to make the computer device execute the radiation simulation calculation method based on multi-physics coupling of the first aspect.

[0024] Compared with the prior art, the present application has the following beneficial effects: The present application adopts ray optics fluence rate theory, RANS k-ε turbulence model and Lagrangian particle tracking multi-physics coupling to calculate the light intensity distribution, fluid flow state and particle motion in the ultraviolet sterilization reactor, and the total radiation dose of microorganisms passing through the ultraviolet sterilization reactor is calculated through the above combination. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The flowchart of the radiation simulation calculation method based on multi-physics coupling of the present application.

[0026] Figure 2 The structure diagram of the ultraviolet disinfection device.

[0027] Figure 3 The cross-sectional view of the fluence rate distribution of the ultraviolet reactor, unit mW / cm 2Color represents fluence rate magnitude.

[0028] Figure 4 Fluence rate distribution histogram on the cross section of the UV reactor.

[0029] Figure 5 Fluid velocity cut plane of the UV reactor. Color represents fluid velocity, and small arrows represent fluid direction.

[0030] Figure 6 Cumulative dose distribution of microorganisms passing through the UV reactor.

[0031] Figure 7 Particle trajectory in the UV reactor. Color represents the survival fraction of microorganisms. DETAILED DESCRIPTION

[0032] The application will be further described below in conjunction with the drawings and specific examples. It should be understood that these examples are only used to illustrate the application and not to limit the scope of the application. The operation methods in the following examples without specific conditions are usually carried out according to the conventional conditions or the conditions suggested by the manufacturers.

[0033] Reference Figure 1 A radiation simulation calculation method based on multi-physical field coupling is used for ultraviolet disinfection equipment. The structure of the ultraviolet disinfection equipment is shown in Figure 2 and includes a reactor. The reactor shell is a steel pipe, and a long tubular quartz guide pipe is arranged inside. The outer side of the quartz guide pipe has a coating that can totally reflect light inward. Water enters at one end and exits at the other end. An ultraviolet lamp is arranged at the middle position in the reactor. The ultraviolet lamp is cylindrical, and its length is consistent with the diameter of the reactor. The specific parameters of the ultraviolet disinfection equipment are shown in Table 1.

[0034] Table 1 Basic parameters of the UV reactor

[0035] Note: The parameters listed in Table 1 can be adjusted.

[0036] Light intensity distribution: The light intensity distribution around the ultraviolet lamp is calculated according to the fluence rate theory of ray optics. The fluence rate is the total radiation power incident on an infinitesimal sphere from all directions, representing the intensity of the spatial cross section receiving ultraviolet radiation power, with a unit of W / m 2 Compared with the irradiance, which calculates the total radiation power incident on a unit plane from all upward directions: in the special case of perfect collimation and vertical incidence, the irradiance and the fluence rate have the same value; but when the radiation inside the reactor comes from all directions, the fluence rate can calculate the total illumination intensity of particles at a certain position in the ultraviolet reactor from all directions, and the formula is as follows:

[0037] wherein: E0: fluence rate (W / m 2 ); t: time (s); V: differential volume (m 3 ); n: ray index; M: total number of rays; Q n : power of ray n (W); C n : velocity of ray n (m / s).

[0038] To visually represent the light intensity distribution in the reactor, the fluence rate distribution cross-sectional plots (as shown in Figure 3 ) and histograms (as shown in Figure 4 ) can be plotted according to the calculation results.

[0039] Fluid calculation: The RANS k-ε turbulence model is used to calculate the velocity distribution of the fluid in the reactor, which is used to represent the fluid velocity u, and the equation is as follows: Continuity equation:

[0040] Time-averaged equation:

[0041] Transport equation of turbulent kinetic energy k:

[0042] Transport equation of turbulent dissipation rate ε:

[0043] wherein: x i , x j : vectors in i and j directions (m), respectively; u i , u j : velocity components in i and j directions (m / s), respectively; f i : unit mass force component in i direction (N / kg); ρ: fluid density (kg / m 3 ); t: time (s); p: fluid pressure (N / m 2 ); v: dynamic viscosity (Pa s); k: turbulent kinetic energy (m2 / s 2 ); : The average velocity in the j-direction (m / s); v t Turbulent viscosity (kg / (m·s)); σ k The Prandtl number of the turbulent kinetic energy k is an empirical constant ≈ 1.0. σ ε The Prandtl number of the turbulent dissipation rate ε is an empirical constant ≈ 1.3-1.5; P k The rate at which energy is transferred from the mean flow to turbulent kinetic energy (kg / (m·s)) 3 )); ε: Turbulent dissipation rate, the rate at which turbulent kinetic energy is converted into heat energy through viscosity (m). 2 / s 3 ); , : Empirical constant, ≈1.44, ≈1.92.

[0044] Given a fixed distribution of ultraviolet light intensity, the disinfection efficiency of the ultraviolet disinfection reactor also depends on the particle motion state with the fluid. A RANS k-ε turbulence model was introduced to simulate the fluid flow pattern within the reactor. Figure 5 This is a cross-sectional view of the fluid velocity in a reactor, used as an example.

[0045] Particle tracking: The following particle tracking equation is used to characterize the velocity of particles moving with the fluid, and to obtain the particle motion state in the reactor at different times:

[0046] in: q: Displacement vector of the particle along the streamline (m); t: time (s); u: fluid velocity (m / s); m p Particle mass (kg); F ext : The net external force vector (N) acting on the particle; : Represents the time (s) corresponding to the change in velocity of a particle in a fluid.

[0047] By coupling the above light intensity distribution, fluid calculation and particle tracking, first, the fluid velocity u in the ultraviolet reactor is solved according to the continuity equation, time-averaged equation, transport equation of turbulent kinetic energy k and transport equation of turbulent dissipation rate ε, and then the differential displacement vector dq of each particle on its streamline and the differential residence time dt of each particle in the fluid are calculated by substituting the particle tracking equation; the total dose of the particle at any point on its trajectory is calculated by substituting the fluence rate E0 solved in the light intensity distribution into the following dose formula.

[0048]

[0049] D: cumulative radiation dose of particles at any point in the reactor (J / m 2 ).

[0050] Microorganisms such as bacteria are regarded as particles, and a microbial inactivation exponential decay model is introduced to predict the proportion of inactivated and / or killed microorganisms, and the calculation formula is as follows:

[0051] Wherein: N(t): represents the number or concentration of active microorganisms in the reactor at a certain time t (CFU / mL); t: time (s); N0: represents the number or concentration of initial particles (active microorganisms) (CFU / mL); k0: inactivation constant (cm 2 / mJ); D: cumulative radiation dose of particles at any point in the reactor (J / m 2 ).

[0052] When the ultraviolet light intensity distribution is determined at the same flow rate, the disinfection efficiency of the reactor mainly depends on the coupling of the particle trajectory and the light intensity distribution. Regarding the simulation results of the survival rate, the present application calculates the cumulative dose distribution of the microorganisms passing through the ultraviolet reactor by particle tracking (for example, as shown in Figure 6 ), and simulates the microbial killing in the reactor according to the decay model (for example, as shown in Figure 7 ).

[0053] A computer device comprises a memory and a processor, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, and the computer program runs to make the processor execute the above-mentioned radiation simulation calculation method based on the coupling of multiple physical fields.

[0054] A computer readable storage medium, a program or instructions are stored on the computer readable storage medium, in the case of program or instructions are executed by the computer equipment, make the computer equipment execute the above-mentioned radiation simulation calculation method based on multi-physical field coupling.

[0055] Furthermore, it is to be understood that even though numerous characteristics and embodiments of the application have been set forth in the foregoing description, many modifications and / or changes of the embodiments of the application in accordance with the application described herein will occur market to those skilled in the art to which the application pertains, without departing from the spirit and scope of this application set forth in the appended claims.

Claims

1. A radiation simulation calculation method based on multiphysics coupling, characterized in that, The radiation simulation calculation method based on multi-physics coupling is used in the field of water treatment. The application scenario is that the water to be treated containing microorganisms flows through an ultraviolet reactor, and the ultraviolet reactor contains a light source that emits ultraviolet light. The radiation simulation calculation method based on multiphysics coupling includes: Calculate the ultraviolet light intensity distribution inside the reactor; Calculate the fluid velocity distribution within the reactor; The velocity of microbial particles moving with the fluid is calculated based on the fluid velocity distribution inside the reactor, thus obtaining the motion state of microbial particles in the reactor; Based on the ultraviolet light intensity distribution and the movement state of microbial particles in the reactor, the total ultraviolet radiation dose received by microbial particles as they flow through the ultraviolet reactor with the water to be treated is calculated.

2. The radiation simulation calculation method based on multiphysics coupling according to claim 1, characterized in that, The ultraviolet light intensity distribution inside the reactor was calculated based on the X-ray optical fluence theory, using the following formula: in: E0: Injection rate; t: time; V: Differential volume; n: X-ray tag; M: Total number of rays; Q n : X-ray power n; C n : Velocity of ray n.

3. The radiation simulation calculation method based on multiphysics coupling according to claim 1, characterized in that, The RANS k-ε turbulence model was used to calculate the fluid velocity distribution within the reactor, and the equations are as follows: Continuity equation: Time-averaging equation: Transport equation for turbulent kinetic energy k: Transport equation for turbulent dissipation rate ε: in: x i x j : These represent vectors in the directions i and j, respectively; u i u j : Represents the velocity components in the i and j directions, respectively; f i : Represents the component of the mass force per unit mass in the i-direction; ρ: fluid density; t: time; p: fluid pressure; v: dynamic viscosity; k: Turbulent kinetic energy; : The average velocity in the j-direction; v t : Turbulent viscosity; σ k : The Prandtl number of turbulent kinetic energy k; σ ε The Prandtl number of the turbulent dissipation rate ε; P k The rate at which energy is transferred from the mean flow to turbulent kinetic energy; ε: Turbulent dissipation rate, the rate at which turbulent kinetic energy is converted into heat energy through viscosity; , : Empirical constant.

4. The radiation simulation calculation method based on multiphysics coupling according to claim 1, characterized in that, Using the following particle tracking equation, the velocity of microbial particles moving with the fluid is calculated, and the motion state of microbial particles in the reactor at different times is obtained: in: q: Displacement vector of microbial particles along streamlines; t: time; u: fluid velocity; m p Microbial particle mass; F ext : The net external force vector acting on the particle; : Represents the time corresponding to the change in velocity of a particle in a fluid.

5. The radiation simulation calculation method based on multiphysics coupling according to claim 1, characterized in that, The formula for calculating the total radiation dose received by a microbial particle at any point on its trajectory is as follows: E0: Injection rate; t: time; D: Cumulative radiation dose of particles at any point within the reactor.

6. The radiation simulation calculation method based on multiphysics coupling according to claim 1, characterized in that, The radiation simulation calculation method based on multi-physics coupling also includes: introducing a microbial inactivation exponential decay model to predict the proportion of inactivated and / or killed microorganisms.

7. The radiation simulation calculation method based on multiphysics coupling according to claim 6, characterized in that, The microbial inactivation index decay model is as follows: in: N(t): represents the number or concentration of active microorganisms in the reactor at a certain time t; t: time; N0: Indicates the initial number or concentration of viable microbial particles; k0: Deactivation constant; D: Cumulative radiation dose of particles at any point within the reactor.

8. A computer device comprising a memory and a processor, the memory for storing a computer program, and the processor for executing the computer program stored in the memory, characterized in that, When the computer program is executed, the processor performs the radiation simulation calculation method based on multiphysics coupling as described in any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a program or instructions, which, when executed by a computer device, cause the computer device to perform the radiation simulation calculation method based on multiphysics coupling as described in any one of claims 1-7.

Images