A method and system for optimizing calculation models of blast furnace particle structure and stress

Abstract

The present invention proposes a method and system for optimizing a calculation model for the structure and stress of blast furnace particles. The method comprises the following steps: calculating the current diameter of the particles based on the initial diameter of the particles in the blast furnace and the current physical properties of the blast furnace particles; determining the piecewise function relationship between the Young's modulus and the current temperature of the particles; and using a discrete element method particle contact model to simulate and calculate the structure and stress of the particles in the blast furnace at the current temperature based on the current diameter of the particles and the piecewise function relationship. Based on this method, a system for optimizing a calculation model for the structure and stress of blast furnace particles is also proposed. The present invention calculates the current diameter of the particles based on the temperature of the particles in the blast furnace, obtains the key parameters of the material layer structure at the particle scale, and proposes control conditions for the discrete element method particle calculation process. The influence of the softening and melting phenomena of the particles during the temperature increase on the interaction force between the particles in the material layer is fully considered, the contact model of the existing discrete element method is optimized, and the accuracy of the numerical simulation calculation of the soft melting zone area of ​​the blast furnace is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of blast furnace smelting, and in particular relates to a method and system for optimizing a calculation model of blast furnace particle structure and stress. Background Art

[0002] The blast furnace ironmaking process involves numerous particle movements, heat transfer, and reaction processes, such as the distribution of blast furnace roof charges and the softening and melting of iron-containing charge and coke in the soft melting zone. Friction and damping between particles within the blast furnace cause deformation of the charge bed structure, affecting the permeability of the porous media structure of the granular bed and directly altering the movement and distribution of reducing gases within the furnace. Therefore, the structure and forces of the charge bed at the particle scale, and their impact on macroscopic gas movement, have become a key topic in current blast furnace process research.

[0003] Blast furnace equipment is a typical black-box reactor. Due to its airtightness and complex and harsh reaction conditions during production, direct information about the production reactions within the furnace cannot be obtained. The discrete element method combined with computational fluid dynamics has become an efficient and reliable computational model for revealing inter-particle interactions, permeability, and calculating gas flow within the blast furnace. Within the blast furnace's soft melting zone, the charge softens and melts. The flowing liquid iron penetrates the porous coke bed and the soft melting zone, hence the name "blast furnace gas distributor." Reasonable explanations for particle softening and melting, and refinement and optimization of existing contact models, are crucial approaches for improving the accuracy of numerical simulations of blast furnaces. Existing contact models fail to consider the effects of particle softening and melting during temperature increases on the inter-particle interactions within the charge layer, resulting in reduced accuracy in numerical simulations of the blast furnace's soft melting zone. Summary of the Invention

[0004] To address these technical issues, the present invention proposes a method and system for optimizing the computational model of blast furnace particle structure and forces. This method fully considers the impact of particle softening and melting during temperature increase on the inter-particle interaction forces in the material layer, optimizes the existing discrete element method contact model, and improves the accuracy of numerical simulations of the blast furnace's soft melting zone.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for optimizing a calculation model of blast furnace particle structure and stress, comprising the following steps:

[0007] Calculate the current diameter of the particles based on the initial diameter of the particles in the blast furnace and the current physical properties of the particles in the blast furnace;

[0008] Determine the piecewise functional relationship between Young's modulus and the current temperature of the particle;

[0009] Based on the current particle diameter and piecewise function relationship, the particle contact model of the discrete element method is used to simulate and calculate the particle structure and force in the blast furnace at the current temperature.

[0010] Furthermore, the current physical properties of the blast furnace particles include the current temperature, softening temperature and melting temperature of the particles.

[0011] Furthermore, the process of calculating the current diameter of the particles according to the initial diameter of the particles in the blast furnace and the current physical properties of the particles in the blast furnace includes:

[0012]

[0013] Where d is the current diameter of the particle; d0 is the initial diameter of the particle in the blast furnace; K is the calculation coefficient; T is the current temperature of the particle; T s is the softening temperature; T m is the melting temperature.

[0014] Furthermore, the piecewise functional relationship between the Young's modulus and the current temperature of the particle is determined;

[0015]

[0016] The F1(T) is the first calculation function of Young's modulus E; F2(T) is the second calculation function of Young's modulus E; k1, k2 and k3 are all constants; T k is greater than T s Less than T k Any value of .

[0017] Furthermore, the particle contact model adopts a CFD-DEM coupling model.

[0018] Furthermore, the process of calculating the particle structure and force in the blast furnace at the current temperature using the particle contact model of the discrete element method includes:

[0019] Using CFD to simulate heat transfer, mass transfer, and momentum transfer in a continuous phase; the continuous phase includes a gas phase and a liquid phase;

[0020] DEM is used to simulate the movement and force of the particle phase and calculate the porosity of the material bed.

[0021] Furthermore, the method further includes: as the temperature increases, when the current diameter of the particle drops to a particle diameter threshold or the particle temperature reaches a melting temperature, no longer performing simulation calculations using the discrete element method.

[0022] The present invention also proposes a calculation model optimization system for blast furnace particle structure and stress, comprising a calculation module, a determination module and a simulation module;

[0023] The calculation module is used to calculate the current diameter of the particles according to the initial diameter of the particles in the blast furnace and the current physical properties of the particles in the blast furnace;

[0024] The determination module is used to determine the piecewise functional relationship between Young's modulus and the current temperature of the particle;

[0025] The simulation module is used to simulate and calculate the particle structure and force in the blast furnace at the current temperature using a particle contact model of a discrete element method based on the current particle diameter and the piecewise function relationship.

[0026] Furthermore, the process implemented by the calculation module includes:

[0027] The current physical properties of the blast furnace particles include the current temperature, softening temperature and melting temperature of the particles.

[0028] The process of calculating the current diameter of the particles according to the initial diameter of the particles in the blast furnace and the current physical properties of the particles in the blast furnace includes:

[0029]

[0030] Where d is the current diameter of the particle; d0 is the initial diameter of the particle in the blast furnace; K is the calculation coefficient; T is the current temperature of the particle; T s is the softening temperature; T m is the melting temperature.

[0031] Furthermore, the process of implementing the simulation module includes:

[0032] Using CFD to simulate heat transfer, mass transfer, and momentum transfer in a continuous phase; the continuous phase includes a gas phase and a liquid phase;

[0033] DEM is used to simulate the movement and force of the particle phase and calculate the porosity of the material bed.

[0034] The effects provided in the summary of the invention are only the effects of the embodiments, not all the effects of the invention. One of the above technical solutions has the following advantages or beneficial effects:

[0035] The present invention proposes a method and system for optimizing a calculation model for the structure and stress of blast furnace particles. The method includes calculating the current diameter of the particles based on the initial diameter of the particles in the blast furnace and the current physical properties of the blast furnace particles; determining the piecewise function relationship between Young's modulus and the current temperature of the particles; and based on the current diameter of the particles and the piecewise function relationship, using a discrete element method particle contact model to simulate and calculate the structure and stress of the particles in the blast furnace at the current temperature. Based on a method for optimizing a calculation model for the structure and stress of blast furnace particles, a system for optimizing a calculation model for the structure and stress of blast furnace particles is also proposed. The present invention can directly calculate the current diameter of the particles based on the temperature of the particles in the blast furnace, obtain the key parameters of the material layer structure at the particle scale, and propose control conditions for the discrete element method particle calculation process. The present invention fully considers the influence of the softening and melting phenomena of the particles during the temperature increase on the interaction force between the particles in the material layer, optimizes the existing discrete element method contact model, and improves the accuracy of numerical simulation calculations in the soft melting zone area of ​​the blast furnace.

[0036] The present invention introduces Young's modulus to describe the relationship between the force between particles and temperature in the soft melting zone of a blast furnace, thereby further improving the calculation accuracy of the existing DEM contact model. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a flow chart of a method for optimizing a calculation model of blast furnace particle structure and stress according to Example 1 of the present invention;

[0038] Figure 2 : is a graph showing the relationship between Young's modulus E and temperature T in Example 1 of the present invention;

[0039] Figure 3 This is a schematic diagram of a calculation model optimization system for blast furnace particle structure and force according to Example 2 of the present invention. DETAILED DESCRIPTION

[0040] In order to clearly illustrate the technical features of this solution, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings. The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. In addition, the present invention may repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplicity and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. It should be noted that the components illustrated in the accompanying drawings are not necessarily drawn to scale. The present invention omits descriptions of well-known components and processing technologies and processes to avoid unnecessary limitations on the present invention.

[0041] Example 1

[0042] Example 1 of the present invention proposes a method for optimizing the calculation model of blast furnace particle structure and force, which solves the problem of modeling and quantitative simulation analysis of factors such as the structure and force of the soft melting zone material layer under high temperature conditions inside the blast furnace, and links the temperature changes of the softening and melting processes of the material layer in the soft melting zone area with the diameter of the furnace charge particles and the force between the particles, thereby improving the coupled calculation model of the blast furnace computational fluid dynamics method (CFD) and discrete element method (DEM).

[0043] like Figure 1 This is a flow chart of a method for optimizing a calculation model of blast furnace particle structure and stress according to Example 1 of the present invention;

[0044] In step S100, the current diameter of the particles is calculated based on the initial diameter of the particles in the blast furnace and the current physical properties of the particles in the blast furnace;

[0045] The current physical properties of blast furnace pellets include the current temperature, softening temperature and melting temperature of the pellets.

[0046] The process of calculating the current diameter of particles based on the initial diameter of particles in the blast furnace and the current physical properties of the particles in the blast furnace includes:

[0047]

[0048] Where d is the current diameter of the particle; d0 is the initial diameter of the particle in the blast furnace; K is the calculation coefficient; T is the current temperature of the particle; T s is the softening temperature; T m is the melting temperature.

[0049] In step S200, the piecewise functional relationship between Young's modulus and the current temperature of the particle is determined. Figure 2 Graph showing the relationship between Young's modulus E and temperature T in Example 1 of the present invention.

[0050]

[0051] The F1(T) is the first calculation function of Young's modulus E; F2(T) is the second calculation function of Young's modulus E; k1, k2 and k3 are constants; T k is greater than T s Less than T k Any value of T in Example 1 of the present invention k Indicates approaching melting temperature.

[0052] When the particle temperature T is lower than the softening temperature T s When the Young's modulus E is a constant or a linear function of the temperature T, when the temperature is greater than or equal to T s Less than the melting temperature T k When the temperature is greater than or equal to the melting temperature T, the Young's modulus E is an exponential function or a quadratic function of the temperature T. kWhen , Young's modulus E is a constant or a linear function of temperature T.

[0053] In step S300, based on the current diameter of the particles and the piecewise function relationship, the particle contact model of the discrete element method is used to simulate and calculate the particle structure and force in the blast furnace at the current temperature.

[0054] The current diameter d of the particle decreases continuously as the temperature increases. When the current diameter of the particle decreases to 0.2d0 or the particle temperature reaches the melting temperature of 1350℃, the particle will no longer be simulated and calculated by the discrete element method.

[0055] Establish the relationship between the particle diameter of blast furnace charge and the temperature of the blast furnace soft melting zone, and form a CFD-DEM coupling model for blast furnace particle simulation;

[0056] The basic solution calculation parameters and boundary conditions are set, and the calculation parameters and boundary conditions include at least: blast furnace tuyere gas velocity, gas temperature, gas density, charge particle density, particle Poisson's ratio, Young's modulus, static friction coefficient and sliding friction coefficient between particles, particle shape and size distribution, particle motion parameters, and time step.

[0057] The particle phase motion control equation is established according to the discrete element method;

[0058] The continuity equation, momentum equation, energy equation and component transport equation of the continuous phase are established based on computational fluid dynamics methods;

[0059] The temperature field distribution of the continuous phase in the blast furnace is calculated according to the computational fluid dynamics method, and the softening and melting state of the particle phase is judged according to the blast furnace particle phase melting judgment standard (i.e., the relationship between diameter and temperature judgment standard). When the particle is judged to be melted, the particle phase melts to form a continuous liquid phase, and the charge begins to move downward. The movement and force between the particles are calculated by the discrete element method. However, when the charge is heated to the point of gradual softening and melting (entering the soft melting zone area), the original shape of the particles can no longer be maintained due to the force, and overlapping deformation occurs between the particles. The structure such as the porosity of the soft melting zone will change significantly. The present invention will describe the overlapping deformation through force and Young's modulus, thereby improving the calculation accuracy of the particle structure inside the blast furnace (especially in the soft melting zone).

[0060] The motion control equations of the discrete element method are mainly derived based on Newton's second law. However, due to the deformation of actual particles (plastic particles) during collision, that is, inelastic collision, many contact models have been developed in the discrete element method to describe the above phenomenon in order to improve the application accuracy and applicability of DEM.

[0061] The blast furnace numerical simulation model is complex. As the furnace is loaded with charge material (granular phase), a porous bed of granular media forms within the furnace. Gas flows through this bed, and complex processes such as momentum transfer, reduction, and heat transfer occur within the furnace. Therefore, a coupled CFD and DEM approach can be used for simulation. CFD simulates the heat, mass, and momentum transfer of the continuous phase (gas and liquid), while DEM simulates the motion and forces of the granular phase and calculates the porosity of the bed.

[0062] In Example 1 of the present invention, the softening and melting temperature ranges of the particles are set according to the physical properties of the blast furnace particles, and the initial diameter d0 of the particles, the current temperature T of the particles, the softening temperature T S The value is 1200℃ and the melting temperature T m Taking the value of 1350℃, the method for calculating the current diameter d of the particle is:

[0063]

[0064] According to the physical properties of blast furnace particles, the relationship between the particle Young's modulus E and the particle temperature T is established as follows:

[0065]

[0066] The particle contact models are Hertz-Mindlin and Deresiewicz models.

[0067] The current diameter d of the particle decreases continuously as the temperature increases. When the current diameter of the particle decreases to 0.2d0 or the particle temperature reaches the melting temperature of 1350℃, the particle will no longer be simulated and calculated by the discrete element method.

[0068] Example 1 of the present invention proposes a method for optimizing a computational model of blast furnace particle structure and forces. This method directly calculates the current particle diameter based on the particle temperature within the blast furnace, deriving key parameters of the material layer structure at the particle scale, and proposes control conditions for the discrete element method particle calculation process. This method fully considers the impact of particle softening and melting during temperature increase on the interaction forces between material layer particles, optimizes the existing discrete element method contact model, and improves the accuracy of numerical simulation calculations in the blast furnace soft melting zone.

[0069] The method for optimizing the calculation model of blast furnace particle structure and force proposed in Example 1 of the present invention further improves the calculation accuracy of the existing DEM contact model by introducing Young's modulus to describe the relationship between the force between particles and temperature in the soft melting zone area of ​​the blast furnace.

[0070] Example 2

[0071] Based on the method for optimizing the calculation model of blast furnace particle structure and stress proposed in Example 1 of the present invention, the system for optimizing the calculation model of blast furnace particle structure and stress proposed in Example 2 of the present invention is as follows: Figure 3 This is a schematic diagram of a calculation model optimization system for blast furnace particle structure and force according to embodiment 2 of the present invention, including a calculation module, a determination module, and a simulation module;

[0072] The calculation module is used to calculate the current diameter of the particles according to the initial diameter of the particles in the blast furnace and the current physical properties of the particles in the blast furnace;

[0073] The determination module is used to determine the piecewise functional relationship between Young's modulus and the current temperature of the particle;

[0074] The simulation module is used to simulate and calculate the particle structure and force in the blast furnace at the current temperature using a particle contact model of a discrete element method based on the current particle diameter and the piecewise function relationship.

[0075] The process implemented by the calculation module includes: the current physical properties of the blast furnace particles include the current temperature, softening temperature and melting temperature of the particles.

[0076] The process of calculating the current diameter of particles based on the initial diameter of particles in the blast furnace and the current physical properties of the particles in the blast furnace includes:

[0077]

[0078] Where d is the current diameter of the particle; d0 is the initial diameter of the particle in the blast furnace; K is the calculation coefficient; T is the current temperature of the particle; T s is the softening temperature; T m is the melting temperature.

[0079] The process of determining module implementation includes:

[0080]

[0081] F1(T) is the first calculation function of Young's modulus E; F2(T) is the second calculation function of Young's modulus E; k1, k2 and k3 are all constants; T k is greater than T s Less than T k Any value of T in Example 1 of the present invention k Indicates approaching melting temperature.

[0082] When the particle temperature T is lower than the softening temperature T s When the Young's modulus E is a constant or a linear function of the temperature T, when the temperature is greater than or equal to T s Less than the melting temperature T k When the temperature is greater than or equal to the melting temperature T, the Young's modulus E is an exponential function or a quadratic function of the temperature T.k When , Young's modulus E is a constant or a linear function of temperature T.

[0083] The process of simulation module implementation includes:

[0084] Using CFD to simulate heat transfer, mass transfer, and momentum transfer in a continuous phase; the continuous phase includes a gas phase and a liquid phase;

[0085] DEM is used to simulate the movement and force of the particle phase and calculate the porosity of the material bed.

[0086] As the temperature increases, when the current particle diameter drops to the particle diameter threshold or the particle temperature reaches the melting temperature, the discrete element method is no longer used for simulation calculation.

[0087] Example 2 of the present invention proposes a computational model optimization system for blast furnace particle structure and forces. This system directly calculates the current particle diameter based on the particle temperature within the blast furnace, deriving key parameters of the material layer structure at the particle scale, and proposes control conditions for the discrete element method particle calculation process. This system fully considers the impact of particle softening and melting during temperature increase on the interaction forces between material layer particles, optimizes the existing discrete element method contact model, and improves the accuracy of numerical simulation calculations in the blast furnace soft melting zone.

[0088] A calculation model optimization system for blast furnace particle structure and force proposed in Example 2 of the present invention further improves the calculation accuracy of the existing DEM contact model by introducing Young's modulus to describe the relationship between the force between particles and temperature in the soft melting zone area of ​​the blast furnace.

[0089] The description of the relevant parts of the calculation model optimization system for blast furnace particle structure and force provided in the embodiment of the present application can be found in the detailed description of the corresponding parts in the calculation model optimization method for blast furnace particle structure and force provided in Example 1 of the present application, and will not be repeated here.

[0090] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device comprising a series of elements are inherent to the elements. In the absence of further restrictions, the elements limited by the statement "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device comprising the elements. In addition, the above-mentioned technical solutions provided in the embodiments of the present application are not described in detail in accordance with the corresponding technical solutions in the prior art to achieve the same principle, so as to avoid excessive elaboration.

[0091] Although the above description is of specific embodiments of the present invention in conjunction with the accompanying drawings, it does not limit the scope of protection of the present invention. For those skilled in the art, other different forms of modifications or variations can be made based on the above description. It is not necessary and impossible to list all embodiments here. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without expending creative effort are still within the scope of protection of the present invention.

Claims

1. A method for optimizing the calculation model of blast furnace particle structure and stress, characterized in that: The following steps are involved: The current diameter of the particles is calculated based on the initial diameter of the particles in the blast furnace and the current physical properties of the particles in the blast furnace; the current physical properties of the particles in the blast furnace include the current temperature, softening temperature and melting temperature of the particles; the process of calculating the current diameter of the particles based on the initial diameter of the particles in the blast furnace and the current physical properties of the particles in the blast furnace includes: ； in, is the current diameter of the particle; is the initial diameter of particles in the blast furnace; is the calculation coefficient; is the current temperature of the particle; is the softening temperature; is the melting temperature; Determine the piecewise functional relationship between Young's modulus and the current temperature of the particle; specifically: ； described is Young's modulus The first calculation function of is Young's modulus The second calculation function of 、 and are all constants; is greater than Less than Any value of Based on the current particle diameter and piecewise function relationship, the particle contact model of the discrete element method is used to simulate and calculate the particle structure and force in the blast furnace at the current temperature.

2. The method for optimizing the calculation model of blast furnace particle structure and stress according to claim 1, characterized in that: The particle contact model adopts a CFD-DEM coupling model.

3. The method for optimizing the calculation model of blast furnace particle structure and stress according to claim 1, characterized in that: The process of calculating the particle structure and force in the blast furnace at the current temperature using the particle contact model of the discrete element method includes: Using CFD to simulate heat transfer, mass transfer, and momentum transfer in a continuous phase; the continuous phase includes a gas phase and a liquid phase; DEM is used to simulate the movement and force of the particle phase and calculate the porosity of the material bed.

4. A method for optimizing the calculation model of blast furnace particle structure and stress according to claim 3, characterized in that: The method further includes: as the temperature increases, when the current diameter of the particle drops to a particle diameter threshold or the particle temperature reaches a melting temperature, no longer performing simulation calculations using the discrete element method.

5. A blast furnace particle structure and force calculation model optimization system, used to execute a blast furnace particle structure and force calculation model optimization method according to any one of claims 1 to 4, characterized in that: It includes calculation module, determination module and simulation module; The calculation module is used to calculate the current diameter of the particles according to the initial diameter of the particles in the blast furnace and the current physical properties of the particles in the blast furnace; The determination module is used to determine the piecewise functional relationship between Young's modulus and the current temperature of the particle; The simulation module is used to simulate and calculate the particle structure and force in the blast furnace at the current temperature using a particle contact model of a discrete element method based on the current particle diameter and the piecewise function relationship.

6. A calculation model optimization system for blast furnace particle structure and stress according to claim 5, characterized in that: The process of implementing the simulation module includes: Using CFD to simulate heat transfer, mass transfer, and momentum transfer in a continuous phase; the continuous phase includes a gas phase and a liquid phase; DEM is used to simulate the movement and force of the particle phase and calculate the porosity of the material bed.

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