Method and system for calculating effective boundary layer thickness of inclusion removal at steel slag interface

Abstract

The present invention belongs to the technical field of high-quality steel smelting, and relates to a method and system for calculating the effective boundary layer thickness of inclusion removal at the steel-slag interface. The method specifically includes the following steps: determining the physical property parameters of the molten steel to be measured and the inclusions in the molten steel, and the flow state at the steel-slag interface; obtaining the calculation domain range and calculation time according to the obtained flow state; first initializing the flow field within the obtained calculation domain range, and then initializing the inclusion distribution; counting the number of inclusions captured by the steel-slag interface after initialization; calculating the effective boundary layer thickness of inclusion removal at the steel-slag interface according to the number of captured inclusions. This method can provide theoretical guidance for quantitatively evaluating the influence of the flow state at the steel-slag interface on the inclusion removal process. More importantly, it can provide a solution for coupling the multiphase flow model and the inclusion removal model in the metallurgical reactor, and further predict the evolution law of the inclusion quantity during the steelmaking and continuous casting processes.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-quality steel smelting, and more specifically, relates to a method and system for calculating the effective boundary layer thickness of inclusion removal at the steel-slag interface. Background Art

[0002] The iron and steel industry is an important basic industry of China's national economy and a pillar industry for realizing industrialization. China is transforming from a large iron and steel country to a powerful iron and steel country. In this process, stricter requirements are put forward for iron and steel products, and the existence of inclusions seriously affects the quality of iron and steel products, such as the fatigue life of bearings, the pitting corrosion performance of stainless steel, the cold drawing fracture of cutting wires, and the bending failure of springs. Therefore, one of the main tasks of metallurgists is to remove as many inclusions in steel as possible to obtain high-purity iron and steel materials.

[0003] In the process of steelmaking production, removing inclusions in steel is one of the main purposes of refining, and adsorption and removal by refining slag is the main way to remove inclusions. It is generally considered that the adsorption and removal of inclusions by refining slag includes three steps: 1) the inclusion moves from the interior of the molten steel to the steel-slag interface, 2) the inclusion separates at the steel-slag interface, and 3) the inclusion dissolves in the slag. In the above steps, how the inclusion changes from moving in the molten steel to being captured by the steel-slag interface is one of the key steps in its removal, and it is also the key to numerical simulation research on the modeling of inclusion removal in the refining process. At present, the research on the capture of inclusions by the steel-slag interface, especially numerical simulation research, mainly considers from the perspective of the self-floating of inclusions, and it is generally considered to be closely related to its floating speed. However, the floating speed of inclusions, that is, the Stokes floating speed, mainly depends on the diameter of the inclusions. It should be noted that whether the inclusion can be captured by the steel-slag interface when moving at the steel-slag interface is not only related to the characteristics of the inclusion itself, but more importantly, it will be affected by the flow state at the steel-slag interface, and this is exactly what needs to be improved. Summary of the Invention

[0004] The present invention discloses a method and system for calculating the effective boundary layer thickness of inclusion removal at the steel-slag interface to solve the above and any potential problems in the prior art.

[0005] To achieve the above object, the technical solution provided by the present invention is: a method for calculating the effective boundary layer thickness of inclusion removal at the steel-slag interface, specifically including the following steps:

[0006] S1): Determine the physical properties of the molten steel to be measured and the inclusions in the molten steel, and the flow state at the steel-slag interface;

[0007] S2): Obtain the calculation domain range and calculation time according to the flow state obtained in S1);

[0008] S3): First, initialize the flow field within the calculation domain obtained in S2), and then initialize the inclusion distribution.

[0009] S4): Count the number of inclusions captured by the steel slag interface after initialization in S3).

[0010] S5): Calculate the effective boundary layer thickness of inclusions removed at the steel slag interface based on the number of captured inclusions.

[0011] Furthermore, the physical property parameters in S1) include: the density ρ of the molten steel l , the viscosity μ of the molten steel l , the density ρ of the inclusions p and the diameter d of the inclusions p ;

[0012] The flow state at the steel slag interface includes: the characteristic flow velocity u of the fluid, the turbulent kinetic energy k, and the characteristic length.

[0013] Furthermore, the specific steps of S2) are as follows:

[0014] S2.1) Assume that the calculation domain is a two-dimensional plane;

[0015] S2.2) Substitute the characteristic length l into the following formula to confirm the calculation domain range, and the formula is as follows:

[0016] {(x,y)|x∈[-l,2l]∩y∈[-5l,l]},

[0017] where: x is the horizontal axis and y is the vertical axis;

[0018] S2.3) Then substitute the characteristic flow velocity u of the fluid into the following formula to calculate the characteristic time, and the formula is as follows:

[0019] t = l / u,

[0020] S2.4) Substitute the obtained characteristic time t into the following formula to find the calculation time step, and the formula is as follows:

[0021] Δt = t / 1000.

[0022] Furthermore, the initialization of the flow field and inclusion distribution in S3) is specifically as follows:

[0023] S3.1) First, initialize the velocity of the flow field within the calculation domain obtained in S2.2) to and then initialize the turbulent kinetic energy to k 0 = k;

[0024] S3.2) Then randomly and uniformly distribute the inclusions within the calculation domain obtained in S2.2), and the total number is N0 , the velocity of the inclusion is initialized to

[0025] where u Stocks is the upward floating velocity of the inclusion:

[0026]

[0027] where g is the acceleration due to gravity, and g is taken as 9.8 m / s 2 .

[0028] Furthermore, the specific steps of the S4) are as follows:

[0029] 4.1) Solve the motion equation of the inclusion by using the physical property parameters collected in S1) as the input of the discrete phase model in fluid mechanics, and finally obtain the motion trajectory of the inclusion at the steel slag interface;

[0030] S4.2) Judge according to the motion trajectory obtained in S4.1) by using the condition that the inclusion is captured by the steel slag interface. If the condition is met, it is considered that the inclusion is captured by the steel slag interface and counted until the calculation time reaches the characteristic time t, and the total number of inclusions captured by the steel slag interface during the whole process is counted, denoted as N.

[0031] Furthermore, the motion trajectory of the inclusion at the steel slag interface in the S4.1) is obtained by solving the motion equation of the inclusion at the steel slag interface by using the discrete phase model (Discrete Phase Model, DPM) in computational fluid dynamics. The inclusion is subjected to the action of buoyancy, drag force, virtual mass force and pressure gradient force at the steel slag interface, and its motion equation can be described by Newton's second law:

[0032]

[0033] where and are the velocity of the inclusion and the instantaneous velocity of the fluid respectively, C D is the drag coefficient, and Re is the Reynolds number corresponding to the inclusion.

[0034] Even further, the Reynolds number Re corresponding to the inclusion is:

[0035]

[0036] Even further, the drag coefficient C D is:

[0037]

[0038] Furthermore, the influence of turbulence at the steel slag interface on the movement of inclusions is considered using the Random Walk Model. The instantaneous velocity of the fluid is the sum of the time-averaged velocity and the pulsating velocity:

[0039]

[0040] where ξ is a random number obeying the standard normal distribution; is the coordinate unit vector.

[0041] Further, the condition for the inclusions in the S4.2) to be captured by the steel slag interface is that the inclusions reach the steel slag interface and the capture position is within the characteristic length range, that is, the inclusion coordinates satisfy (0 ≤ x p ≤ l) ∩ (y p ≥ 0).

[0042] Further, the specific steps of the S5) are as follows: Substitute the total number of inclusions captured by the steel slag interface statistically in the S4.2) into the following formula, and the effective boundary layer thickness of the inclusions removed at the steel slag interface can be obtained. The formula is as follows:

[0043]

[0044] Another object of the present invention is to provide a system for implementing a method for calculating the effective boundary layer thickness of inclusions removed at the steel slag interface. The system includes:

[0045] An acquisition module for acquiring the physical property parameters of the molten steel to be measured and the inclusions in the molten steel, as well as the flow state at the steel slag interface;

[0046] A processing module for analyzing and processing the data collected by the acquisition module;

[0047] An initialization module for initializing the inclusion distribution according to the collected data and the processed data;

[0048] An analysis and judgment module: for judging according to the condition that the inclusions are captured by the steel slag interface. If the condition is met, it is considered that the inclusions are captured by the steel slag interface and counted.

[0049] A data output module: for outputting the effective boundary layer thickness of the inclusions removed at the steel slag interface according to the counting result.

[0050] A computer storage medium, on which a computer program is stored, and the computer program is executed by a processor to implement the above method for calculating the effective boundary layer thickness of inclusions removed at the steel slag interface.

[0051] The beneficial effects of the present invention are as follows: By adopting the above technical solution, the present invention solves the movement trajectory of inclusions at the steel slag interface, then counts the number of inclusions captured at the steel slag interface, and further calculates the effective boundary layer thickness of inclusion removal at the steel slag interface. In the present invention, the effective boundary layer thickness is not only related to the diameter of the inclusions themselves, but also depends on the fluid velocity and turbulent kinetic energy at the steel slag interface, providing theoretical guidance for quantitatively evaluating the influence of the flow state at the steel slag interface on the inclusion removal process. More importantly, it can provide a solution for coupling the multiphase flow model and inclusion removal model in the metallurgical reactor, and then predict the evolution law of the number of inclusions during the steelmaking and continuous casting processes. Description of the Drawings

[0052] Figure 1 It is a flow chart of a calculation method for calculating the effective boundary layer thickness of inclusion removal at the steel slag interface according to the present invention.

[0053] Figure 2 It is a schematic diagram of the effective boundary layer thickness of inclusion removal at the steel slag interface in the present invention.

[0054] Figure 3 It is a schematic diagram of the random and uniform distribution of inclusions in the calculation domain using the calculation method of the present invention.

[0055] Figure 4 It is a logic block diagram of a system for calculating the effective boundary layer thickness of inclusion removal at the steel slag interface according to the present invention. Detailed Embodiments

[0056] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the relevant art without creative efforts belong to the scope of protection of the present invention.

[0057] As Figure 1 shown, a method for calculating the effective boundary layer thickness of inclusion removal at the steel slag interface according to the present invention specifically includes the following steps:

[0058] S1): Determine the physical property parameters of the molten steel to be measured and the inclusions in the molten steel, and the flow state at the steel slag interface;

[0059] S2): Obtain the calculation domain range and calculation time according to the flow state obtained in S1);

[0060] S3): First, initialize the flow field within the calculation domain range obtained in S2), and then initialize the inclusion distribution;

[0061] S4): Count the number of inclusions captured by the steel slag interface after initialization in S3).

[0062] S5): Calculate the effective boundary layer thickness of inclusion removal at the steel slag interface based on the number of captured inclusions.

[0063] The physical property parameters in S1) include: the density ρ of the molten steel l , the viscosity μ of the molten steel l , the density ρ of the inclusions p and the diameter d of the inclusions p ;

[0064] The flow state at the steel slag interface includes: the characteristic flow velocity u of the fluid, the turbulent kinetic energy k, and the characteristic length l.

[0065] The specific steps of S2) are as follows:

[0066] S2.1) Assume the computational domain is a two-dimensional plane;

[0067] S2.2) Substitute the characteristic length l into the following formula to confirm the computational domain range, and the formula is as follows:

[0068] {(x,y)|x∈[-l,2l]∩y∈[-5l,l]},

[0069] where: x is the horizontal axis and y is the vertical axis;

[0070] S2.3) Then substitute the characteristic flow velocity u of the fluid into the following formula to calculate the characteristic time, and the formula is as follows:

[0071] t = l / u,

[0072] S2.4) Substitute the obtained characteristic time t into the following formula to find the computational time step, and the formula is as follows:

[0073] Δt = t / 1000.

[0074] The initialization of the flow field and inclusion distribution in S3) is specifically as follows:

[0075] S3.1) First, initialize the velocity of the flow field within the computational domain obtained in S2.2) to Then initialize the turbulent kinetic energy to k 0 = k;

[0076] S3.2) Then randomly and uniformly distribute the inclusions within the computational domain obtained in S2.2), and the total number is N 0 , and initialize the velocity of the inclusions to the velocity of the inclusions to be

[0077] where, uStocks is the upward floating velocity of inclusions:

[0078]

[0079] In the formula, g is the gravitational acceleration, and g is taken as 9.8 m / s 2 .

[0080] The specific steps of the said S4) are as follows:

[0081] 4.1) Solve the motion equation of inclusions by using the physical property parameters collected in S1) as the input of the discrete phase model in fluid mechanics, and finally obtain the motion trajectory of inclusions at the steel slag interface;

[0082] S4.2) Judge according to the motion trajectory obtained in S4.1) by using the condition that inclusions are captured by the steel slag interface. If the condition is met, it is considered that the inclusions are captured by the steel slag interface and counted until the calculation time reaches the characteristic time t, and the total number of inclusions captured by the steel slag interface during the whole process is counted, denoted as N.

[0083] In the said S4.1), the motion trajectory of inclusions at the steel slag interface is obtained by solving the motion equation of inclusions at the steel slag interface by using the discrete phase model (Discrete Phase Model, DPM) in computational fluid dynamics. The inclusions are subjected to the action of buoyancy, drag force, virtual mass force and pressure gradient force at the steel slag interface, and its motion equation can be described by Newton's second law:

[0084]

[0085] Among them, and are the velocity of inclusions and the instantaneous velocity of the fluid respectively, C D is the drag coefficient, and Re is the Reynolds number corresponding to the inclusions.

[0086] Furthermore, the Reynolds number Re corresponding to the inclusions is:

[0087]

[0088] Furthermore, the drag coefficient C D is:

[0089]

[0090] Furthermore, the influence of turbulence at the steel slag interface on the motion of inclusions is considered by using the random walk model (Random Walk Model), then the instantaneous velocity of the fluid is the sum of the time-averaged velocity and the pulsating velocity:

[0091]

[0092] Among them, ξ is a random number subject to the standard normal distribution; is the coordinate unit vector.

[0093] The condition for the inclusion in the S4.2) to be captured by the steel slag interface is that the inclusion reaches the steel slag interface and the capture position is within the characteristic length range, that is, the inclusion coordinates satisfy (0 ≤ x p ≤ l) ∩ (y p ≥ 0).

[0094] The specific steps of the S5) are as follows: Substitute the total number of inclusions captured by the steel slag interface counted in the S4.2) into the following formula, and the effective boundary layer thickness of the inclusion removal at the steel slag interface can be obtained. The formula is as follows:

[0095]

[0096] As Figure 4 shown, a system for implementing a method for calculating the effective boundary layer thickness of inclusion removal at the steel slag interface according to the present invention, the system includes:

[0097] A collection module, used for the physical property parameters of the molten steel to be measured and the inclusions in the molten steel, as well as the flow state at the steel slag interface;

[0098] A processing module, used for analyzing and processing the data collected by the collection module;

[0099] An initialization module, used for initializing the inclusion distribution according to the collected data and the processed data;

[0100] An analysis and judgment module: used for judging according to the condition that the inclusion is captured by the steel slag interface, and if the condition is met, it is considered that the inclusion is captured by the steel slag interface and counted;

[0101] A data output module: used for outputting the effective boundary layer thickness of inclusion removal at the steel slag interface according to the counting result.

[0102] A computer storage medium, on which a computer program is stored, and the computer program is executed by a processor to implement the above method for calculating the effective boundary layer thickness of inclusion removal at the steel slag interface.

[0103] Example 1

[0104] This example mainly aims at large-sized (d p = 100 μm) alumina inclusions during the steelmaking process under weak turbulence (u = 0.001 m / s, k = 0.001 m 2 / s 2)Calculation method for removing the effective boundary layer thickness at the steel slag interface under Figure 1 the conditions, where the characteristic length is l = 0.1 m, and the specific steps are as follows (as

[0105] Determine the physical properties of the molten steel and inclusions. The density of the molten steel is ρ l = 7080 kg / m 3 , the viscosity of the molten steel is μ l = 0.0067 kg / (m·s), the density of the inclusions is ρ p = 3500 kg / m 3 , and the diameter of the inclusions is d p = 100 μm; Determine the flow state at the steel slag interface. The characteristic flow velocity of the fluid is u = 0.001 m / s, and the turbulent kinetic energy is k = 0.001 m 2 / s 2 .

[0106] Determine the calculation domain range and calculation time. Assume the calculation domain is a two-dimensional plane, the characteristic length is l = 0.1 m, and the characteristic time is t = l / u = 100 s. Therefore, the calculation domain range is {(x, y)|x ∈ [-0.1 m, 0.2 m] ∩ y ∈ [-0.5 m, 0.1 m]}; The calculation time is t ∈ [0, 100 s]; The calculation time step is Δt = t / 1000 = 0.1 s.

[0107] Initialization of the flow field and inclusion distribution. The initialization of the flow field velocity is The initialization of the turbulent kinetic energy is k 0 = 0.001 m 2 / s 2 , and it remains unchanged in the calculation of the inclusion movement trajectory; The inclusions are randomly and uniformly distributed in the region of {(x, y)|x ∈ [0, 0.1 m] ∩ y ∈ [-0.5 m, 0]} (as Figure 3 shown), and the total number is N 0 = 100000. The initial velocity of the inclusions is where u Stocks is the upward floating velocity of the inclusions:

[0108]

[0109] Determine the condition for the inclusions to be captured by the steel slag interface. The condition for the inclusions to be captured by the steel slag interface is that the inclusions reach the steel slag interface and the capture position is within the characteristic length range, that is, the inclusion coordinates satisfy (0 ≤ x p ≤ 0.1 m) ∩ (y p ≥ 0).

[0110] Calculate the movement trajectory of inclusions at the steel slag interface. The movement trajectory of inclusions at the steel slag interface is obtained by solving the movement equation of inclusions at the steel slag interface. Inclusions at the steel slag interface are subjected to the actions of buoyancy, drag force, virtual mass force, and pressure gradient force, and its movement equation can be described by Newton's second law:

[0111]

[0112] Among them, and are the velocity of the inclusion and the instantaneous velocity of the fluid respectively, C D is the drag coefficient, and Re is the Reynolds number corresponding to the inclusion.

[0113] Furthermore, the Reynolds number Re corresponding to the inclusion is:

[0114]

[0115] Furthermore, the drag coefficient C D is:

[0116]

[0117] Furthermore, the influence of turbulence at the steel slag interface on the movement of inclusions is considered by using the Random Walk Model. Then the instantaneous velocity of the fluid is the sum of the time-averaged velocity and the pulsating velocity:

[0118]

[0119] Among them, ξ is a random number obeying the standard normal distribution; is the coordinate unit vector.

[0120] Use the computational fluid dynamics software FLUENT to solve the equation to obtain the movement trajectory of inclusions at the steel slag interface.

[0121] Statistical the number of inclusions captured by the steel slag interface. During the process of solving the movement trajectory of inclusions at the steel slag interface, it is judged with the condition for determining that the inclusions are captured by the steel slag interface. If the determined condition for the inclusions to be captured by the steel slag interface is satisfied, it is considered that the inclusions are captured by the steel slag interface and counted until the calculation time reaches the characteristic time of 100 s. Finally, the total number of inclusions captured by the steel slag interface during the whole process is counted, denoted as N = 26480.

[0122] Calculate the effective boundary layer thickness for the removal of inclusions at the steel slag interface. The effective boundary layer thickness for the removal of inclusions at the steel slag interface can be calculated by the following formula:

[0123]

[0124] Therefore, for alumina inclusions with a diameter of 100 μm during the steelmaking process under turbulent conditions of u = 0.001 m / s and k = 0.001 m 2 / s 2 when the characteristic length is 0.1 m, the effective boundary layer thickness for the removal of inclusions at the steel - slag interface is 0.1320 m, as Figure 2 shown.

[0125] Example 2

[0126] This example mainly focuses on the calculation method of the effective boundary layer thickness for the removal of small - size (d p = 1 μm) alumina inclusions at the steel - slag interface under strong turbulent conditions (u = 0.1 m / s, k = 0.1 m 2 / s 2 ), where the characteristic length is l = 0.1 m. The specific steps are as follows (as Figure 2 shown):

[0127] Determine the physical properties of the molten steel and inclusions. The density of the molten steel is ρ l = 7080 kg / m 3 , the viscosity of the molten steel is The density of the inclusions is ρ p = 3500 kg / m 3 , the diameter of the inclusions is d p = 1 μm; Determine the flow state at the steel - slag interface. The characteristic flow velocity of the fluid is u = 0.1 m / s, and the turbulent kinetic energy is k = 0.1 m 2 / s 2 .

[0128] Determine the calculation domain range and calculation time. Assume the calculation domain is a two - dimensional plane, the characteristic length is l = 0.1 m, the characteristic time is t = l / u = 1 s. Therefore, the calculation domain range is {(x,y)|x∈[-0.1m,0.2m]∩y∈[-0.5m,0.1m]}; The calculation time is t∈[0,1s]; The calculation time step is Δt = t / 1000 = 0.001 s.

[0129] Initialization of the flow field and inclusion distribution. The initialization of the flow field velocity is The initialization of the turbulent kinetic energy is k 0 = k = 0.1 m 2 / s 2 , and it remains unchanged in the calculation of the inclusion movement trajectory; The inclusions are randomly and uniformly distributed in the region of {(x,y)|x∈[0,0.1m]∩y∈[-0.5m,0]} (as Figure 3 shown), and the total number is N 0= 100000. The initial velocity of the inclusion is where u Stocks is the upward floating velocity of the inclusion:

[0130]

[0131] Determine the condition for the inclusion to be captured by the steel slag interface. The condition for the inclusion to be captured by the steel slag interface is that the inclusion reaches the steel slag interface and the capture position is within the characteristic length range, that is, the inclusion coordinates satisfy (0 ≤ x p ≤ 0.1 m) ∩ (y p ≥ 0).

[0132] Calculate the movement trajectory of the inclusion at the steel slag interface. The movement trajectory of the inclusion at the steel slag interface is obtained by solving the movement equation of the inclusion at the steel slag interface. The inclusion is subjected to the action of buoyancy, drag force, virtual mass force and pressure gradient force at the steel slag interface, and its movement equation can be described by Newton's second law:

[0133]

[0134] where and are the velocity of the inclusion and the instantaneous velocity of the fluid respectively, C D is the drag coefficient, and Re is the Reynolds number corresponding to the inclusion.

[0135] Furthermore, the Reynolds number Re corresponding to the inclusion is:

[0136]

[0137] Furthermore, the drag coefficient C D is:

[0138]

[0139] Furthermore, the instantaneous velocity of the fluid is the sum of the time-averaged velocity and the pulsating velocity:

[0140]

[0141] where ξ is a random number obeying the standard normal distribution; is the coordinate unit vector.

[0142] Use the computational fluid dynamics software FLUENT to solve the equation to obtain the movement trajectory of the inclusion at the steel slag interface.

[0143] The number of inclusions captured by the steel slag interface is counted by judging with the condition for determining the capture of inclusions by the steel slag interface during the process of solving the movement trajectory of inclusions at the steel slag interface. If the condition for determining the capture of inclusions by the steel slag interface is met, it is considered that the inclusions are captured by the steel slag interface and counted until the calculation time reaches the characteristic time of 1 s. Finally, the total number of inclusions captured by the steel slag interface during the whole process is counted, N = 6882.

[0144] The effective boundary layer thickness for the removal of inclusions at the steel slag interface is calculated. The effective boundary layer thickness for the removal of inclusions at the steel slag interface can be calculated by the following formula:

[0145]

[0146] Therefore, for alumina inclusions with a diameter of 1 μm during the steelmaking process under the turbulent flow conditions of u = 0.1 m / s and k = 0.1 m 2 / s 2 when the characteristic length is 0.1 m, the effective boundary layer thickness for the removal of inclusions at the steel slag interface is 0.0334 m.

[0147] A method and system for calculating the effective boundary layer thickness for the removal of inclusions at the steel slag interface according to the present invention can overcome the deficiency in the existing research that it is difficult to couple the removal of inclusions at the steel slag interface with the multiphase flow in the metallurgical reactor. The effective boundary layer theory is the basic theory for studying the interfacial chemical reaction between steel and slag. It assumes that there are two thin films on both sides of the steel slag interface respectively, and the mass transfer resistance of the interfacial chemical reaction completely exists in the thin film close to the interface. This thin film is called the effective boundary layer. By using the method of the present invention, the effective boundary layer thickness for the capture and removal of inclusions by the steel slag interface under different turbulent flow conditions can be calculated (as Figure 2 shown), which provides theoretical guidance for quantitatively evaluating the influence of the flow state at the steel slag interface on the inclusion removal process. More importantly, it can provide a solution for coupling the multiphase flow model and the inclusion removal model in the metallurgical reactor, and then predict the evolution law of the number of inclusions during the steelmaking and continuous casting processes. This theory provides an idea for studying the removal of inclusions at the steel slag interface.

[0148] The above has introduced in detail a method and system for calculating the effective boundary layer thickness for the removal of inclusions at the steel slag interface provided by the embodiment. The description of the above embodiment is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

[0149] As used in the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not distinguish components by the difference in names, but by the difference in functions. As used throughout the specification and claims, the terms "comprising" and "including" are open-ended terms and should be interpreted as "comprising / including but not limited to". "Substantially" means within an acceptable error range. Those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The following description in the specification is the preferred embodiment for implementing the present application, but the description is for the purpose of explaining the general principles of the present application and not for limiting the scope of the present application. The protection scope of the present application shall be determined by the scope defined in the appended claims.

[0150] It should also be noted that the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a commodity or system including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such commodity or system. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the commodity or system including the said element.

[0151] It should be understood that the term "and / or" used herein is only a relationship describing the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally indicates that the associated objects before and after are in an "or" relationship.

[0152] The above description shows and describes several preferred embodiments of the present application. However, as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the application concept described herein through the above teachings or the technology or knowledge in the relevant field. And any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present application shall fall within the protection scope of the appended claims of the present application.

Claims

1. A method for calculating the effective boundary layer thickness of inclusion removal at the steel slag interface, characterized in that, it specifically includes the following steps: S1): Determine the physical properties of the molten steel to be measured and the inclusions in the molten steel, and the flow state at the steel slag interface; The physical properties parameters include: the density ρ of the molten steel l , the viscosity μ of the molten steel, the density ρ p of the inclusions, and the diameter d p ; The flow state at the steel slag interface includes: the characteristic flow velocity u of the fluid, the turbulent kinetic energy k, and the characteristic length l; S2): Calculate the calculation domain range and calculation time according to the flow state obtained in S1); S3): First, initialize the flow field within the calculation domain range obtained in S2), and then initialize the inclusion distribution; S4): Count the number of inclusions captured by the steel slag interface after initialization in S3); S5): Calculate the effective boundary layer thickness of inclusion removal at the steel slag interface based on the number of captured inclusions.

2. The method according to claim 1, characterized in that, the specific steps of S2) are: S2.1) Assume that the calculation domain is a two-dimensional plane; S2.2) Substitute the characteristic length l into the following formula to confirm the calculation domain range, and the formula is as follows: {(x,y)|x∈[-l,2l]∩y∈[-5l,l]}, where: x is the horizontal axis and y is the vertical axis; S2.3) Then substitute the characteristic flow velocity u of the fluid into the following formula to calculate the characteristic time, and the formula is as follows: t = l / u, S2.4) Substitute the obtained characteristic time t into the following formula to calculate the calculation time step, and the formula is as follows: Δt = t / 1000.

3. The method according to claim 2, characterized in that, the initialization of the flow field and inclusion distribution in S3) is specifically: S3.1) First, initialize the velocity of the flow field within the computational domain obtained in S2.2) as Then, initialize the turbulent kinetic energy as k 0 = k; S3.2) Then randomly and evenly distribute the inclusions within the computational domain obtained in S2.2), with the total initial number being N 0 , and initialize the velocity of the inclusions to where u Stocks is the upward floating velocity of the inclusions: where g is the acceleration due to gravity, and g is taken as 9.8 m / s 2 .

4. The method according to claim 3, characterized in that, the specific steps of S4) are: S4.1) Use the physical property parameters collected in S1) as the input of the discrete phase model in fluid mechanics to solve the motion equation of inclusions, and finally obtain the motion trajectory of inclusions at the steel slag interface; S4.2) Judge according to the motion trajectory obtained in S4.1) using the condition that inclusions are captured by the steel slag interface. If the condition is met, it is considered that the inclusions are captured by the steel slag interface and counted until the calculation time reaches the characteristic time t, and the total number of inclusions captured by the steel slag interface during the whole process is counted and recorded as N.

5. The method according to claim 4, characterized in that, The condition for the inclusions in the S4.2) to be captured by the steel slag interface is that the inclusions reach the steel slag interface and the capture position is within the characteristic length range, that is, the coordinates of the inclusions satisfy (0 ≤ x p ≤ l) ∩ (y p ≥ 0).

6. The method according to claim 4, characterized in that, the specific steps of S5) are: Substitute the total number of inclusions captured by the steel slag interface counted in S4.2) into the following formula to calculate the effective boundary layer thickness of inclusion removal at the steel slag interface, and the formula is as follows:

7. A system for implementing the method for calculating the effective boundary layer thickness of inclusion removal at the steel slag interface according to any one of claims 1-6, characterized in that, the system includes: a collection module for the physical property parameters of the molten steel to be measured and the inclusions in the molten steel, and the flow state at the steel slag interface; a processing module for analyzing and processing the data collected by the collection module; an initialization module for initializing the inclusion distribution according to the collected data and the processed data; Analysis and judgment module: used to judge according to the conditions for inclusions to be captured by the steel slag interface. If the conditions are met, it is considered that the inclusions are captured by the steel slag interface and counted; Data output module: used to output the effective boundary layer thickness of inclusion removal at the steel slag interface according to the counting result.

8. A computer storage medium, characterized in that, a computer program is stored on the medium, and the computer program is executed by a processor to implement the method for calculating the effective boundary layer thickness of inclusion removal at the steel slag interface according to any one of claims 1-6.

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